684 results on '"Gravity compensation"'
Search Results
2. Evaluation of a passive wearable arm ExoNET.
- Author
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Ryali, Partha, Wilson, Valentino, Celian, Courtney, Srivatsa, Adith V., Ghani, Yaseen, Lentz, Jeremy, Patton, James, Sawicki, Gregory S., and Badesa, Francisco Javier
- Subjects
WRIST ,TRICEPS ,ACTIVITIES of daily living ,FORELIMB - Abstract
Wearable ExoNETs offer a novel, wearable solution to support and facilitate upper extremity gravity compensation in healthy, unimpaired individuals. In this study, we investigated the safety and feasibility of gravity compensating ExoNETs on 10 healthy, unimpaired individuals across a series of tasks, including activities of daily living and resistance exercises. The direct muscle activity and kinematic effects of gravity compensation were compared to a sham control and no device control. Mixed effects analysis revealed significant reductions in muscle activity at the biceps, triceps and medial deltoids with effect sizes of -3.6%, -4.5%, and -7.2% rmsMVC, respectively, during gravity support. There were no significant changes in movement kinematics as evidenced by minimal change in coverage metrics at the wrist. These findings reveal the potential for the ExoNET to serve as an alternative to existing bulky and encumbering devices in post-stroke rehabilitation settings and pave the way for future clinical trials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Development of a gravity compensation device for rotary joint using magnetic energy.
- Author
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Zhu, Weizheng, Shan, Leimeng, and Lee, Kyung-min
- Subjects
- *
MAGNETIC energy storage , *GRAVITY , *GRAVITATIONAL energy , *PERMANENT magnets , *ENERGY storage - Abstract
A gravity compensation (GC) device compensates for the torque originating from a constant mass or payload, which occupies a large part of the capacity and energy consumption of an actuator on the joint. Adapting a GC device can reduce energy consumption and capacity of the actuator. A GC device comprises an energy-storage component and a motion-converting mechanism. The energy storage component stores and releases energy according to the change in gravitational energy as the mass of the joint rotates. The motion-converting mechanism matches the energy from the energy storage component to the gravitational energy of the rotating mass. The majority of GC devices use springs as the energy storage component, and they are connected to the body by motion-converting mechanisms, such as gears and slide cranks. A GC device that uses magnetic energy as an energy storage component was proposed in this study. It uses noncontact permanent magnets (PMs) as energy storage components. It is designed to have a simple structure and compact size, and can be easily connected to the actuator module, similar to commercial gear reducers. It comprises two identical structures, consisting of one yoke and two PMs. The two structures are assembled as the PMs face each other and generate attractive and repulsive forces depending on the relative angle between the two facing PMs. The shapes of the PMs were determined to generate a sinusoidal torque profile to compensate for the gravitational torque by a mass. The designed mechanism is verified through simulations and experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. A Micro-vibration Test Method for Satellite Based on Dual-Stage Gravity Compensation System
- Author
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Zhu, Jianbin, Zhang, Wenbing, Liu, Chuang, Qiu, Hanping, Lu, Dongdong, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Haddar, Mohamed, Series Editor, Cavas-Martínez, Francisco, Editorial Board Member, di Mare, Francesca, Editorial Board Member, Kwon, Young W., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Xu, Jinyang, Editorial Board Member, Rui, Xiaoting, editor, and Liu, Caishan, editor
- Published
- 2024
- Full Text
- View/download PDF
5. An Adaptive Controller for Payload Swing Suppression of Ship-Mounted Boom Cranes
- Author
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Li, Bincheng, Liao, Peng, Zhang, Menghua, Ning, Donghong, Liu, Guijie, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Tan, Kay Chen, Series Editor, Jing, Xingjian, editor, Ding, Hu, editor, Ji, Jinchen, editor, and Yurchenko, Daniil, editor
- Published
- 2024
- Full Text
- View/download PDF
6. A Design Concept of Linear-Type Gravity Compensation Using Permanent-Magnet Arrays
- Author
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Zeng, Xiangxian, Kuo, Chin-Hsing, Sariyildiz, Emre, Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, and Okada, Masafumi, editor
- Published
- 2024
- Full Text
- View/download PDF
7. Anti-Swaying Control Strategy of Ship-Mounted 3-RCU Parallel Platform Based on Dynamic Gravity Compensation.
- Author
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Lv, Zhiyuan, Liu, Pengfei, Ning, Donghong, and Wang, Shuqing
- Subjects
GRAVITY ,CENTER of mass ,MARITIME shipping ,OCEAN waves ,DEGREES of freedom ,GRAVIMETRY - Abstract
It is essential to ensure stability during marine transportation or the installation of high center of gravity loads. The heavy loads increase gravity disturbance, affecting the steady-state-error control of the multiple degrees of freedom (DOFs) motion compensation platform. In this paper, we propose a proportional derivative (PD) controller with dynamic gravity compensation (PDGC) for a 3-RCU (revolute–cylindrical–universal) parallel platform to improve the control effect of marine motion compensation for high center of gravity loads. We introduce an evaluation parameter of load stability and a weighting coefficient of anti-swaying control to tune the controller performance. The controller can set its control target between the two, keeping the load contact surface level and allowing the load center of gravity with the least movement. By deriving the Jacobian matrix, the gravity disturbance in the joint space is calculated and is compensated in the controller. First, we verify the control superiority of this controller over the PD controller under sinusoidal excitation in simulation and validate the effectiveness of the proposed anti-swing strategy. Then, the experiments are conducted with random excitation. The root mean square (RMS) value of the load's residual angle with the proposed controller is reduced to 32.2% and 17.6% in two directions, respectively, compared with the PD controller under class 4 sea state excitation. The proposed method is effective for the anti-swaying control of ship-mounted 3-RCU parallel platforms. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. 基于势能守恒的被动式微低重力模拟系统平衡因素.
- Author
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兰超, 韩大鹏, 王兆魁, and 陈力
- Abstract
Copyright of Journal of Fuzhou University is the property of Journal of Fuzhou University, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
9. 空间串联机构重力平衡设计方法与仿真分析.
- Author
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胡松华, 杨竣皓, 孙利雄, and 李树东
- Abstract
Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
10. Trajectory Tracking and Disturbance Rejection Performance Analysis of Classical and Advanced Controllers for a SCORBOT Robot.
- Author
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Kern, John, Urrea, Claudio, Verdejo, Humberto, Agramonte, Rayko, and Becker, Cristhian
- Subjects
ROBOTS ,MOBILE robots ,RANGE of motion of joints ,DYNAMIC models ,STANDARD deviations ,TORQUE control ,TORQUE - Abstract
This work presents the design and assessment of four control schemes for the monitoring and regulation of joint trajectories applied in the dynamic model of a SCORBOT-ER V plus robot, which includes the dynamics of the actuators, and the estimation of the friction forces present within the joints. The two classical control strategies calculated torque and PID, and the two advanced control strategies, fuzzy and predictive, are considered. In the latter case, a gravitational compensation stage is incorporated, as well as the inverse models of the motors and the transmissions of belt movement for each joint. Computational tests are performed by applying an external step-type disturbance to the third joint of the robot. Finally, an evaluation of the results obtained is presented through trajectory curves, joint errors, and the three performance indexes residual mean square, residual standard deviation, and index of agreement. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. Dynamic and Static Assistive Strategies for a Tailored Occupational Back-Support Exoskeleton: Assessment on Real Tasks Carried Out by Railway Workers.
- Author
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Di Natali, Christian, Poliero, Tommaso, Fanti, Vasco, Sposito, Matteo, and Caldwell, Darwin G.
- Subjects
- *
ROBOTIC exoskeletons , *BACK muscles , *LIFTING & carrying (Human mechanics) , *MATERIALS handling , *TASK analysis , *RAILROADS - Abstract
This study on occupational back-support exoskeletons performs a laboratory evaluation of realistic tasks with expert workers from the railway sector. Workers performed both a static task and a dynamic task, each involving manual material handling (MMH) and manipulating loads of 20 kg, in three conditions: without an exoskeleton, with a commercially available passive exoskeleton (Laevo v2.56), and with the StreamEXO, an active back-support exoskeleton developed by our institute. Two control strategies were defined, one for dynamic tasks and one for static tasks, with the latter determining the upper body's gravity compensation through the Model-based Gravity Compensation (MB-Grav) approach. This work presents a comparative assessment of the performance of active back support exoskeletons versus passive exoskeletons when trialled in relevant and realistic tasks. After a lab characterization of the MB-Grav strategy, the experimental assessment compared two back-support exoskeletons, one active and one passive. The results showed that while both devices were able to reduce back muscle activation, the benefits of the active device were triple those of the passive system regarding back muscle activation ( 26 % and 33 % against 9 % and 11 % , respectively), while the passive exoskeleton hindered trunk mobility more than the active mechanism. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. Force Tracking Control Method for Robotic Ultrasound Scanning System under Soft Uncertain Environment.
- Author
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Jiang, Jinlei, Luo, Jingjing, Wang, Hongbo, Tang, Xiuhong, Nian, Fan, and Qi, Lizhe
- Subjects
SCANNING systems ,STEADY-state responses ,ROBOTICS ,ADAPTIVE control systems ,ROBOT control systems ,ULTRASONIC imaging ,KELVIN probe force microscopy - Abstract
Robotic ultrasound scanning has excellent potential to reduce physician workload, obtain higher-quality imaging, and reduce costs. However, the traditional admittance control strategy for robotics cannot meet the high-precision force control requirements for robots, which are critical for improving image quality and ensuring patient safety. In this study, an integral adaptive admittance control strategy is proposed for contact force control between an ultrasound probe and human skin to enhance the accuracy of force tracking. First, a robotic ultrasound scanning system is proposed, and the system's overall workflow is introduced. Second, an adaptive admittance control strategy is designed to estimate the uncertain environmental information online, and the estimated parameters are used to modify the reference trajectory. On the basis of ensuring the stability of the system, an integral controller is then introduced to improve the steady-state response. Subsequently, the stability of the proposed strategy is analysed. In addition, a gravity compensation process is proposed to obtain the actual contact force. Finally, through a simulation analysis, the effectiveness of the strategy is discussed. Simultaneously, a series of experiments are carried out on the robotic ultrasound scanning system, and the results show that the strategy can successfully maintain a constant contact force under soft uncertain environments, which effectively improves the efficiency of scanning. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
13. Evaluation of a passive wearable arm ExoNET
- Author
-
Partha Ryali, Valentino Wilson, Courtney Celian, Adith V. Srivatsa, Yaseen Ghani, Jeremy Lentz, and James Patton
- Subjects
medical Robot ,wearable Design ,Exoskeletons ,pilot Study ,gravity compensation ,Mechanical engineering and machinery ,TJ1-1570 ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
Wearable ExoNETs offer a novel, wearable solution to support and facilitate upper extremity gravity compensation in healthy, unimpaired individuals. In this study, we investigated the safety and feasibility of gravity compensating ExoNETs on 10 healthy, unimpaired individuals across a series of tasks, including activities of daily living and resistance exercises. The direct muscle activity and kinematic effects of gravity compensation were compared to a sham control and no device control. Mixed effects analysis revealed significant reductions in muscle activity at the biceps, triceps and medial deltoids with effect sizes of −3.6%, −4.5%, and −7.2% rmsMVC, respectively, during gravity support. There were no significant changes in movement kinematics as evidenced by minimal change in coverage metrics at the wrist. These findings reveal the potential for the ExoNET to serve as an alternative to existing bulky and encumbering devices in post-stroke rehabilitation settings and pave the way for future clinical trials.
- Published
- 2024
- Full Text
- View/download PDF
14. A Novel Passive Shoulder Exoskeleton Using Link Chains and Magnetic Spring Joints
- Author
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Hyun-Ho Lee, Kyung-Taek Yoon, Hyun-Ho Lim, Won-Kyu Lee, Jae-Hwan Jung, Seung-Beom Kim, and Young-Man Choi
- Subjects
Exoskeleton ,magnetic spring ,link chains ,scapulohumeral rhythm ,electromyography ,gravity compensation ,Medical technology ,R855-855.5 ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Work-related musculoskeletal disorders represent a major occupational disability issue, and 53.4% of these disorders occur in the back or shoulders. Various types of passive shoulder exoskeletons have been introduced to support the weight of the upper arm and work tools during overhead work, thereby preventing injuries and improving the work environment. The general passive shoulder exoskeleton is constructed with rigid links and joints to implement shoulder rotation, but there exists a challenge to align with the flexible joint movements of the human shoulder. Also, a force-generating part using mechanical springs require additional mechanical components to generate torque similar to the shoulder joint, resulting in increased overall volume and inertia to the upper arm. In this study, we propose a new type of passive shoulder exoskeleton that uses magnetic spring joint and link chain. The redundant degrees of freedom in the link chains enables to follow the shoulder joint movement in the horizontal direction, and the magnetic spring joint generates torque without additional parts in a compact form. Conventional exoskeletons experience a loss in the assisting torque when the center of shoulder rotation changed during arm elevation. Our exoskeleton minimizes the torque loss by customizing the installation height and initial angle of the magnetic spring joint. The performances of the proposed exoskeleton were verified by an electromyographic evaluation of shoulder-related muscles in overhead work and box lifting task.
- Published
- 2024
- Full Text
- View/download PDF
15. A Novel Spatial 3-DoF Constant-Force Generator for the Static Balancing of Parallel Robots
- Author
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Mottola, G., Martini, A., Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, and Okada, Masafumi, editor
- Published
- 2023
- Full Text
- View/download PDF
16. Irregular-Shaped Torsion Spring Design for Gravity Compensation in Linkage Systems: A Modified CPRBM Based Methodology
- Author
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Shan, Zexin, Endo, Mitsuru, Nakamura, Hiroshi, Tanaka, Shimpei, Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, and Okada, Masafumi, editor
- Published
- 2023
- Full Text
- View/download PDF
17. The Motion Suspension System – MSS: A Cable-Driven System for On-Ground Tests of Space Robots
- Author
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Elhardt, Ferdinand, Boumann, Roland, De Stefano, Marco, Heidel, Robin, Lemmen, Patrik, Heumos, Martin, Jeziorek, Christoph, Roa, Maximo A., Schedl, Manfred, Bruckmann, Tobias, Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, and Okada, Masafumi, editor
- Published
- 2023
- Full Text
- View/download PDF
18. Hardness Tester for Analog Planetary Rocks: A Preliminary Assessment in Microgravity Flight
- Author
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Pires, Ana, Costa, Catarina, Moura, Rui, Persad, Aaron H., Reimuller, Jason, Gowanlock, Derek, Alavi, Shahrukh, Beatty, Heather Wright, Almeida, José, Almeida, Fernando, Silva, Eduardo, Pérez-Alberti, Augusto, Chaminé, Helder I., Pisello, Anna Laura, Editorial Board Member, Hawkes, Dean, Editorial Board Member, Bougdah, Hocine, Editorial Board Member, Rosso, Federica, Editorial Board Member, Abdalla, Hassan, Editorial Board Member, Boemi, Sofia-Natalia, Editorial Board Member, Mohareb, Nabil, Editorial Board Member, Mesbah Elkaffas, Saleh, Editorial Board Member, Bozonnet, Emmanuel, Editorial Board Member, Pignatta, Gloria, Editorial Board Member, Mahgoub, Yasser, Editorial Board Member, De Bonis, Luciano, Editorial Board Member, Kostopoulou, Stella, Editorial Board Member, Pradhan, Biswajeet, Editorial Board Member, Abdul Mannan, Md., Editorial Board Member, Alalouch, Chaham, Editorial Board Member, O. Gawad, Iman, Editorial Board Member, Nayyar, Anand, Editorial Board Member, Amer, Mourad, Series Editor, Chaminé, Helder I., editor, and Fernandes, José Augusto, editor
- Published
- 2023
- Full Text
- View/download PDF
19. Design of a Passive Assistive Exoskeleton for Improving Overall Worker Productivity in Industries
- Author
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Amal, Parth, Mayekar, Nimish, Patil, Atharva, Sooryavanshi, Shreevardhan, Ramesh, Rajguru, Vasudevan, Hari, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Cavas-Martínez, Francisco, Editorial Board Member, di Mare, Francesca, Editorial Board Member, Haddar, Mohamed, Editorial Board Member, Kwon, Young W., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Vasudevan, Hari, editor, Kottur, Vijaya Kumar N., editor, and Raina, Amool A., editor
- Published
- 2023
- Full Text
- View/download PDF
20. Design Optimization of a Four-Bar Leg Linkage for a Legged-Wheeled Balancing Robot
- Author
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Klemm, Victor, Mannhart, Dominik, Siegwart, Roland, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Cascalho, José M., editor, Tokhi, Mohammad Osman, editor, Silva, Manuel F., editor, Mendes, Armando, editor, Goher, Khaled, editor, and Funk, Matthias, editor
- Published
- 2023
- Full Text
- View/download PDF
21. The effects of facioscapulohumeral dystrophy and dynamic arm support on upper extremity muscle coordination in functional tasks.
- Author
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Essers, J.M.N., Meijer, K., Peters, A.A., and Murgia, A.
- Subjects
- *
DYSTROPHY , *FORELIMB , *ARM muscles , *MUSCLE weakness , *ASSISTIVE technology , *ACTIVITIES of daily living - Abstract
• First study on muscle coordination in people with FSHD during ADL arm tasks. • People with FSHD have very diverse muscle coordination patterns compared to controls. • Assistive device does not reduce muscle coordination diversity in people with FSHD. This study's objective is to understand the effect of muscular weakness in persons with facioscapulohumeral dystrophy as well as the effect of a dynamic arm support on muscle coordination and activity performance, during activities of daily living. People with facioscapulohumeral dystrophy (n=12, 56.0±14.5 years) and healthy controls (n=12, 55.5±13.4 years) performed five simulated daily activity tasks, while unsupported and supported by the Gowing dynamic arm support. Surface electromyography, kinematics, and maximum force output were recorded. Outcomes were calculated for muscle coordination (muscle synergies), maximum muscle activity, movement performance indicators, and upper limb muscular weakness (maximum force output). Muscle coordination was altered and less consistent in persons with facioscapulohumeral dystrophy compared with healthy controls. The dynamic arm support alleviated muscle efforts and affected muscle coordination in both populations. While populations became more similar, the internal consistency of persons with facioscapulohumeral dystrophy remained unaffected and lower than that of healthy controls. Furthermore, the support affected movements' performance in both groups. The maximum force outputs were lower in persons with facioscapulohumeral dystrophy than controls. Muscle coordination differences were presumably the result of individual-specific in muscle weakness and compensatory strategies for dealing with gravity compensation and movement constraints. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
22. Position‐based force tracking adaptive impedance control strategy for robot grinding complex surfaces system.
- Author
-
Li, Lun, Wang, Zhengjia, Zhu, Guang, and Zhao, Jibin
- Subjects
IMPEDANCE control ,ADAPTIVE control systems ,ROBOT control systems ,KALMAN filtering - Abstract
As a key technology of robot grinding, force control has great influence on grinding effects. Based on the traditional impedance control, a position‐based force tracking adaptive impedance control strategy is proposed to improve the grinding quality of aeroengine complex curved parts, which considers the stiffness damping environmental interaction model, modifies the reference trajectory by a Lyapunov‐based approach to realize the adaptive grinding process. In addition, forgotten Kalman filter based on six‐dimensional force sensor is used to denoise the force information and a three‐step gravity compensation process including static base value calculation, dynamic zero update and contact force real‐time calculation is proposed to obtain the accurate contact force between tool and workpiece in this method. Then, to verify the effectiveness of the proposed method, a simulation experiment which including five different working conditions is conducted in MATLAB, and the experiment studying the deviation between the reference trajectory and the actual position is carried out on the robot grinding system. The results indicate that the position‐based force tracking adaptive impedance control strategy can quickly respond to the changes of environmental position, reduce the fluctuation range of contact force in time by modifying the reference trajectory, compensate for the defect of the steady‐state error of the traditional impedance control strategy and improve the surface consistency of machined parts. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
23. Anti-Swaying Control Strategy of Ship-Mounted 3-RCU Parallel Platform Based on Dynamic Gravity Compensation
- Author
-
Zhiyuan Lv, Pengfei Liu, Donghong Ning, and Shuqing Wang
- Subjects
multiple DOFs ,motion compensation ,parallel platform ,gravity compensation ,anti-swaying ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
It is essential to ensure stability during marine transportation or the installation of high center of gravity loads. The heavy loads increase gravity disturbance, affecting the steady-state-error control of the multiple degrees of freedom (DOFs) motion compensation platform. In this paper, we propose a proportional derivative (PD) controller with dynamic gravity compensation (PDGC) for a 3-RCU (revolute–cylindrical–universal) parallel platform to improve the control effect of marine motion compensation for high center of gravity loads. We introduce an evaluation parameter of load stability and a weighting coefficient of anti-swaying control to tune the controller performance. The controller can set its control target between the two, keeping the load contact surface level and allowing the load center of gravity with the least movement. By deriving the Jacobian matrix, the gravity disturbance in the joint space is calculated and is compensated in the controller. First, we verify the control superiority of this controller over the PD controller under sinusoidal excitation in simulation and validate the effectiveness of the proposed anti-swing strategy. Then, the experiments are conducted with random excitation. The root mean square (RMS) value of the load’s residual angle with the proposed controller is reduced to 32.2% and 17.6% in two directions, respectively, compared with the PD controller under class 4 sea state excitation. The proposed method is effective for the anti-swaying control of ship-mounted 3-RCU parallel platforms.
- Published
- 2024
- Full Text
- View/download PDF
24. Force Tracking Control Method for Robotic Ultrasound Scanning System under Soft Uncertain Environment
- Author
-
Jinlei Jiang, Jingjing Luo, Hongbo Wang, Xiuhong Tang, Fan Nian, and Lizhe Qi
- Subjects
robotic ultrasound scanning ,gravity compensation ,integral adaptive control ,admittance control ,force tracking ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Production of electric energy or power. Powerplants. Central stations ,TK1001-1841 - Abstract
Robotic ultrasound scanning has excellent potential to reduce physician workload, obtain higher-quality imaging, and reduce costs. However, the traditional admittance control strategy for robotics cannot meet the high-precision force control requirements for robots, which are critical for improving image quality and ensuring patient safety. In this study, an integral adaptive admittance control strategy is proposed for contact force control between an ultrasound probe and human skin to enhance the accuracy of force tracking. First, a robotic ultrasound scanning system is proposed, and the system’s overall workflow is introduced. Second, an adaptive admittance control strategy is designed to estimate the uncertain environmental information online, and the estimated parameters are used to modify the reference trajectory. On the basis of ensuring the stability of the system, an integral controller is then introduced to improve the steady-state response. Subsequently, the stability of the proposed strategy is analysed. In addition, a gravity compensation process is proposed to obtain the actual contact force. Finally, through a simulation analysis, the effectiveness of the strategy is discussed. Simultaneously, a series of experiments are carried out on the robotic ultrasound scanning system, and the results show that the strategy can successfully maintain a constant contact force under soft uncertain environments, which effectively improves the efficiency of scanning.
- Published
- 2024
- Full Text
- View/download PDF
25. Dynamic and Static Assistive Strategies for a Tailored Occupational Back-Support Exoskeleton: Assessment on Real Tasks Carried Out by Railway Workers
- Author
-
Christian Di Natali, Tommaso Poliero, Vasco Fanti, Matteo Sposito, and Darwin G. Caldwell
- Subjects
industrial exoskeleton ,back-support exoskeleton ,assistive control ,gravity compensation ,real working task ,Technology ,Biology (General) ,QH301-705.5 - Abstract
This study on occupational back-support exoskeletons performs a laboratory evaluation of realistic tasks with expert workers from the railway sector. Workers performed both a static task and a dynamic task, each involving manual material handling (MMH) and manipulating loads of 20 kg, in three conditions: without an exoskeleton, with a commercially available passive exoskeleton (Laevo v2.56), and with the StreamEXO, an active back-support exoskeleton developed by our institute. Two control strategies were defined, one for dynamic tasks and one for static tasks, with the latter determining the upper body’s gravity compensation through the Model-based Gravity Compensation (MB-Grav) approach. This work presents a comparative assessment of the performance of active back support exoskeletons versus passive exoskeletons when trialled in relevant and realistic tasks. After a lab characterization of the MB-Grav strategy, the experimental assessment compared two back-support exoskeletons, one active and one passive. The results showed that while both devices were able to reduce back muscle activation, the benefits of the active device were triple those of the passive system regarding back muscle activation (26% and 33% against 9% and 11%, respectively), while the passive exoskeleton hindered trunk mobility more than the active mechanism.
- Published
- 2024
- Full Text
- View/download PDF
26. A Novel Method for Stride Length Estimation Using Wireless Foot Sensor Module.
- Author
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Das, Ratan and Kumar, Neelesh
- Subjects
- *
ANATOMICAL planes , *DETECTORS , *GRAVITY , *FREE convection - Abstract
This work presents a novel method for the estimation of stride length (SL) from inertial sensor-based wireless foot sensor module (WFSM). SL variability is a widely used and clinically relevant spatial gait parameter. This work proposes and validates a novel method for computing SL by measuring the foot inclination angle and single-axis acceleration measured from WFSM. The foot inclination angle is used for detecting gait events as well as for gravity compensation to estimate the real acceleration of the foot. This approach thus requires minimum input information, i.e. foot angle trajectory and acceleration in only sagittal plane. The results are validated on a cohort of healthy subjects against a standard gait analysis platform. A set of trial data on 10 healthy volunteers were also analysed for outdoor walking to evaluate the performance against previously reported works. The proposed approach has the potential for applications involving real-time gait measurements. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
27. Design and Evaluation of AX-Deminer Forearm Assistance for Demining Soldier
- Author
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Myunghyun Lee, Yongcheol Kim, Gwang Tae Kim, Sang Hun Joo, and Man Bok Hong
- Subjects
Forearm assistance ,gravity compensation ,mine detection ,wearable device ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Mine clearance operation using a mine detector often strains arm muscles because of the extended form of the detection pole. Implementing a gravity compensation device may be beneficial for alleviating this issue. Therefore, this paper presents a novel concept of passive-type forearm assistance for mine-detection soldiers. The proposed forearm assistance features a decoupled structure between a sweeping module and a gravity compensation unit. The sweeping module is implemented using a planar serial chain, allowing the required range of arm-sweeping motion for mine detection. The gravity compensation module, featuring a six-bar linkage with a linear spring, is located at the wearer’s back and compensates the detector’s weight transmitted through the sweeping module. The decoupled structure enables minimal exposure of the mechanism to the wearer. Design requirements are determined from motion analysis of mine-detection soldiers; kinematic relationships are derived for sweeping and gravity compensation modules. Based on the kinematic relationships, optimal synthesis methods are presented to determine design parameters. The proposed gravity compensation device has been experimentally validated for four mine-detection soldiers. Electromyography measurements of the upper limb demonstrate a significant reduction of up to 66% in % maximum voluntary contraction (MVC) when using forearm assistance. Thus, the proposed forearm assistance may reduce arm fatigue, enabling more extended operation duration during mine clearance tasks.
- Published
- 2023
- Full Text
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28. A Modularization Approach for Gravity Compensation of Planar Articulated Robotic Manipulators
- Author
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Nguyen, Vu Linh, Kuo, Chin-Hsing, Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, and Arakelian, Vigen, editor
- Published
- 2022
- Full Text
- View/download PDF
29. A New Class of Spring Four-Bar Mechanisms for Gravity Compensation
- Author
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Nguyen, Vu Linh, Kuo, Chin-Hsing, Lin, Po Ting, Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, Khang, Nguyen Van, editor, and Hoang, Nguyen Quang, editor
- Published
- 2022
- Full Text
- View/download PDF
30. Gravity Compensation of Articulated Robots Using Spring Four-Bar Mechanisms
- Author
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Nguyen, Vu Linh, Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, Pucheta, Martín, editor, Cardona, Alberto, editor, Preidikman, Sergio, editor, and Hecker, Rogelio, editor
- Published
- 2022
- Full Text
- View/download PDF
31. Development of Pneumatic Force-Controlled Actuator for Automatic Robot Polishing Complex Curved Plexiglass Parts.
- Author
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Zhang, Xinyu and Sun, Yuwen
- Subjects
PNEUMATIC actuators ,AIR cylinders ,ROBOTS ,ACTUATORS ,SURFACE forces ,MATHEMATICAL models - Abstract
Due to the temperature-sensitive characteristic of plexiglass materials, it is necessary to maintain a constant small contact force to avoid surface burn damage when polishing complex curved plexiglass parts. To handle the issue, in this paper a pneumatic force-controlled actuator was developed to keep the normal contact force between the polishing tool and the workpiece constant during the robotic polishing process. The force-controlled actuator is configured with a double-acting cylinder as the driving element, and two electrical proportional valves are used to control the output force by adjusting the pressure difference between the two air chambers of the cylinder. In this case, a small contact force can be exactly achieved, and the cylinder can always work within the optimal pressure range. In order to judge the stability of the system and reduce the commissioning time of the force-controlled actuator, a mathematical model of the force-controlled actuator is established. Meanwhile, for eliminating the influence of the gravity of the polishing tool on the contact force control, a gravity compensation algorithm is also given according to the roll-pitch-yaw (RPY) angle calculation method. Since there are some nonlinear factors in the operation of the force-controlled actuator, a fuzzy proportion-integral-derivative (PID) control strategy is adopted without steady-state errors. Finally, the polishing experiment of a complex curved plexiglass part was carried out by using the robot automatic polishing system. The experimental results show that the contact force control effect of the force-controlled actuator meets the processing requirements, and the curved plexiglass part has good surface quality and optical performance after polishing. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. Design of a Novel Haptic Joystick for the Teleoperation of Continuum-Mechanism-Based Medical Robots.
- Author
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Xie, Yiping, Hou, Xilong, and Wang, Shuangyi
- Subjects
REMOTE control ,JOYSTICKS ,IMPEDANCE control ,MOMENTS of inertia ,SPEED limits ,ROBOTS - Abstract
Continuum robots are increasingly used in medical applications and the master–slave-based architectures are still the most important mode of operation in human–machine interaction. However, the existing master control devices are not fully suitable for either the mechanical mechanism or the control method. This study proposes a brand-new, four-degree-of-freedom haptic joystick whose main control stick could rotate around a fixed point. The rotational inertia is reduced by mounting all powertrain components on the base plane. Based on the design, kinematic and static models are proposed for position perception and force output analysis, while at the same time gravity compensation is also performed to calibrate the system. Using a continuum-mechanism-based trans-esophageal ultrasound robot as the test platform, a master–slave teleoperation scheme with position–velocity mapping and variable impedance control is proposed to integrate the speed regulation on the master side and the force perception on the slave side. The experimental results show that the main accuracy of the design is within 1.6°. The workspace of the control sticks is −60° to 110° in pitch angle, −40° to 40° in yaw angle, −180° to 180° in roll angle, and −90° to 90° in translation angle. The standard deviation of force output is within 8% of the full range, and the mean absolute error is 1.36°/s for speed control and 0.055 N for force feedback. Based on this evidence, it is believed that the proposed haptic joystick is a good addition to the existing work in the field with well-developed and effective features to enable the teleoperation of continuum robots for medical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
33. Gravity compensation of a 2R1T mechanism with remote center of motion for minimally invasive transnasal surgery applications.
- Author
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Aldanmaz, Ataol Behram, Ayit, Orhan, Kiper, Gökhan, and Dede, Mehmet İsmet Can
- Subjects
- *
MINIMALLY invasive procedures , *PARALLEL kinematic machines , *PARALLEL robots , *GRAVITY , *PENDULUMS , *CENTER of mass , *GRAVIMETERS (Geophysical instruments) - Abstract
This work addresses the gravity balancing of a 2R1T (2 rotations – 1 translation) mechanism with remote center of motion. A previously developed balancing solution is modified and applied to a prototype, and test results are presented. The mechanism is an endoscope holder for minimally invasive transnasal pituitary gland surgery. In this surgery, the endoscope is inserted through a nostril of the patient through a natural path to the pituitary gland. During the surgery, it is vital for the manipulator to be statically balanced so that in case of a motor failure, the patient is protected against any harmful motion of the endoscope. Additionally, static balancing takes the gravitational load from the actuators and hence facilitates the control of the mechanism. The mechanism is a 2URRR-URR type parallel manipulator with three legs. The payload mass is distributed to the legs on the sides. By using counter-masses for two links of each leg, the center of mass of each leg is lumped on the proximal link which simplifies the problem of balancing of a two degree-of-freedom inverted pendulum. The two proximal links with the lumped mass are statically balanced via springs. Dynamic simulations indicate that when the mechanism is statically balanced, generated actuator torques are reduced by 93.5%. Finally, the balancing solution is implemented on the prototype of the manipulator. The tests indicate that the manipulator is statically balanced within its task space when the actuators are disconnected. When the actuators are connected, the torque requirements decrease by about 37.8% with balancing. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Development of Shoulder Muscle-Assistive Wearable Device for Work in Unstructured Postures.
- Author
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Jeon, Kwang-Woo, Chung, Hyun-Joon, Jung, Eui-Jung, Kang, Jeon-Seong, Son, So-Eun, and Yi, Hak
- Subjects
SHOULDER ,SHOULDER joint ,POSTURE ,MOTION capture (Human mechanics) ,MUSCLE fatigue ,FIBROUS composites - Abstract
The present study describes the development of a wearable device designed to assist those who work in an unstructured posture. In the manufacturing sector, industrial accidents have been steadily on the rise due to poor work environments and excessive workloads imposed on workers. Against this backdrop, the present study aimed to analyze various types of work, especially those performed in unstructured postures by heavy industry workers, who are frequently exposed to high workloads and poor work environments. Based on the analysis results, an attempt was made to develop a shoulder muscle-assistive wearable device capable of assisting a wearer who is working using their shoulder muscles. Various types of unstructured posture work are performed in heavy industries, including activities such as the welding and grinding of ship components and plant structures. They are typically conducted in narrow spaces with limited postures, causing many workers to suffer muscle fatigue. In the present study, as the first step of developing a shoulder muscle-assistive wearable device, different working scenarios were simulated, and the corresponding motion data and required torque values were estimated using motion capture devices. The obtained motion data and required torque values were reflected in the design of the wearable device. The main structural body of the shoulder muscle-assistive wearable device was made of a carbon fiber-reinforced composite to be lightweight. This shoulder muscle-assistive wearable device was designed to fully cover the range of motion for workers working in unstructured postures while generating the torque required for a given job, thereby enhancing the muscular endurance of the workers. The gravity compensation module of the designed shoulder muscle-assistive wearable device generates a support force of 4.47 Nm per shoulder. The shoulder muscle assistive wearable device was developed to provide support for approximately 30% of the shoulder joint's maximum torque generated in overhead tasks. This shoulder muscle-assistive wearable device is expected to contribute to improving the productivity of field workers, while reducing the occurrence of musculoskeletal injuries arising from the aging of the working-age population. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. Experimental Study of Robotic Polishing Process for Complex Violin Surface.
- Author
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Wahballa, Hosham, Duan, Jinjun, Wang, Wenlong, and Dai, Zhendong
- Subjects
GRINDING & polishing ,VIOLIN ,ROBOTICS ,WOODEN beams ,SINGLE-degree-of-freedom systems ,SURFACE area ,GRAVITY - Abstract
This paper presents a robotic polishing process for complex violin surfaces to increase efficiency and minimize the cost and consumed time caused by using labor and traditional polishing machines. The polishing process is implemented based on modeling a smooth path, controlled contact force embedded with gravity compensation and material removal depth. A cubic Non-Uniform Rational Bases-Spline (NURBS) interpolation curve combined with an S-curve trajectory model is used to generate a smooth polishing path on a complex violin surface to achieve stable motion during the polishing process. An online admittance controller added to the fast gravity compensation algorithm maintains an accurate polishing force for equal removal depth on all polished surface areas. Then, based on Pythagorean theory, the removal depth model is calculated for the violin's complex surface before and after polishing to estimate the accuracy of the polishing process. Experimental studies were conducted by polishing a wooden surface using the 6DOF robot manipulator to validate this methodology. The experimental results demonstrated that the robot had accurate polishing force based on the online admittance controller with gravity compensation. It also showed a precise proportional uniformity of removal depths at the different normal forces of 10, 15, and 20 N. The final results indicated that the proposed experimental polishing approach is accurate and polishes complex surfaces effectively. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
36. Static Modeling of a Class of Stiffness-Adjustable Snake-like Robots with Gravity Compensation.
- Author
-
Hu, Jian, Liu, Tangyou, Zeng, Haijun, Chua, Ming Xuan, Katupitiya, Jayantha, and Wu, Liao
- Subjects
GRAVITY ,ROBOT kinematics ,MINIMALLY invasive procedures ,BIPEDALISM - Abstract
Stiffness-adjustable snake-like robots have been proposed for various applications, including minimally invasive surgery. Based on a variable neutral-line mechanism, previous works proposed a class of snake-like robots that can adjust their stiffness by changing the driving cables' tensions. A constant curvature hypothesis was used to formulate such robots' kinematics and was further verified by our previous work via rigorous force analysis and ADAMS simulations. However, all these models and analyses have ignored the effect of the robot links' gravity, resulting in significant errors in real systems. In this paper, a static model considering gravity compensation is proposed for the stiffness-adjustable snake-like robots. The proposed model adopts a nonlinear Gauss–Seidel iteration scheme and consists of two parts: gravity update and pose estimation. In each iteration, the former updates the payload of each link caused by gravity, and the latter estimates the pose of the robot by refreshing the angle and position values. This iteration stops when the change in the tip position is less than a pre-set error ϵ. During the above process, the only dependent information is each cable's tension. Simulations and experiments are carried out to verify the effectiveness of the proposed model. The impact of gravity is found to increase with growing material densities in the simulations. The experimental results further indicate that compared with a model without gravity compensation, our model reduces the tip estimation error by 91.5% on average. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
37. Position and Attitude Control Based on Single Neuron PID With Gravity Compensation for Quad Rotor UAV
- Author
-
Haitao Zhang and Lulu Yang
- Subjects
Quad rotor UAV system ,Double closed loop ,Single neuron ,Gravity compensation ,Technology ,Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
Aimed at the deficiency of existing PID controller for quad rotor UAV, a single neuron PID controller with gravity compensation is presented. After using feed forward control to compensate gravity, the position loop adopts PID control to ensure control accuracy, while the attitude loop adopts single neuron control to increase adaptive ability. Then, by using Matlab/simulink simulation software, the position control of quad rotor UAV is carried out, and the simulation result shows, compared with the traditional double closed loop PID controller, the control algorithm based on the Single Neuron adaptive PID with gravity compensation can effectively improve the robustness and adaptability of the quad rotor UAV system.
- Published
- 2023
38. 基于模糊PID的悬吊式机械臂重力补偿控制系统设计.
- Author
-
李崇智
- Abstract
Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
- Full Text
- View/download PDF
39. Design of a novel cable-driven parallel robot for 3D printing building construction.
- Author
-
Lee, Chang-Hwan and Gwak, Kwan-Woong
- Subjects
- *
PARALLEL robots , *BUILDING design & construction , *THREE-dimensional printing , *CONSTRAINED optimization , *ENERGY consumption - Abstract
A novel cable-driven parallel robot (CDPR), featured with a simple structure and energy-efficient driving mechanism, for 3D printing building construction is proposed, and details of the design methodology are presented. To overcome the limitation of the previous approaches, the CDPR is designed to operate with only five cables; hence, its structure is simplified. To avoid the interference with the building being printed, lower cables are placed on a plane parallel to the ground and they are controlled to move synchronously up and down according to the height of the building being printed. Tension distribution of the cables required for the operation is analyzed using the constrained optimization problem. Workspace determination is presented in consideration of the cable strength as well using the tension distribution analysis. A gravity compensation mechanism is proposed and applied to reduce the energy consumption. The validity of the proposed CDPR and design methodology is verified through the simulation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
40. Design of a Compact Gear-Spring Mechanism for Static Balancing of Variable Payloads.
- Author
-
Vu Linh Nguyen
- Subjects
- *
GEARING machinery , *ENERGY consumption , *ROBOT design & construction , *CONCEPTUAL design - Abstract
The design of mechanisms for the static balancing of a rotating and weight-varying link has tremendous implications for mechanical structures and robotic systems. This article presents a compact gear-spring mechanism (CGSM) for the static balancing of variable payloads. The CGSM is constructed with a three-gear train and a tension spring mounted on a rotating link with a mass to be statically balanced. The static balancing design of the CGSM is realized by imposing geometrical constraints on the links and then deriving the spring parameters from analytical equations. The payload variability of the CGSM is obtained through an energy-free adjustment of the settling position of the spring when the rotating link is vertical. A theoretical model and experimental tests are provided to demonstrate the performance of the CGSM. Experimental studies showed that the CGSM could be maintained over a prescribed workspace without input forces. The actuator torque and accumulated energy consumption of the CGSM were practically decreased by up to 89.4% and 95.7%, respectively, within a range of payloads from 0.2 kg to 0.8 kg. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
41. Research on Gravity Compensation System of Planetary Rover Based on Electrodynamic Suspension.
- Author
-
Qiu, Xue-song, Li, Dong-sheng, Li, Meng-xu, Sun, Qian-yuan, and Shang, Kuo
- Abstract
In this paper, an electrodynamic levitation gravity compensation system based on a new type of annular Halbach array permanent magnet is proposed. The magnetic levitation force model is established using the equivalent expansion method, and the reliability of the model is verified by comparing the results of numerical calculation and simulation analysis. Through magnetic field simulation experiments, the effects of rotating speed and air gap on magnetic levitation force and eddy current loss are analyzed. The control model of the electric magnetic levitation system considering the vertical speed is investigated, and the hybrid control method of force and position is used to realize the stable magnetic levitation control. Finally, an experimental platform is built to verify the feasibility of the electric magnetic levitation system. The results show that the magnetic levitation force can be improved and the eddy current loss can be reduced by setting the rotating speed and air gap reasonably. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
42. Zero-Free-Length Elastic System for Gravity Compensation of Parallel Mechanisms With Delta and Delta-Like Architectures.
- Author
-
Lixing Jin, Quanbin Lai, Rui Ma, Weijun Zhang, Xingguang Duan, and Changsheng Li
- Subjects
- *
GRAVITY , *ERROR rates , *PARALLEL robots , *ACTUATORS - Abstract
Passive gravity compensation can effectively reduce the load of actuators, but existing methods are commonly complex in terms of mechanisms and elastic systems with zero-free-length (ZFL) property. A compensation strategy using all joint information is further developed in this paper, as well as the involved elastic system. This approach with considerable compensation effect is simple in principle, and the ZFL property is precisely and completely realized by commercial springs. Compared with the previous method, the process of spring selection is also greatly simplified. Possible arrangements with approximate compensation are also calculated and discussed to achieve a compromise between the compensation effect and the mechanism complexity. The elastic system for Delta-like is implemented and calibrated as an illustration. The results show that the stiffness error rate is reduced from 23.53% to 3.92% and the compensation effect is improved by 63.36% for full compensation and 24.01% for approximate compensation, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
43. Design and evaluation of a four-DoF upper limb exoskeleton with gravity compensation.
- Author
-
Shi, Ke, Yang, Jun, Hou, Zhimin, and Yu, Haoyong
- Subjects
- *
ROBOTIC exoskeletons , *HUMAN-robot interaction , *NUMERICAL calculations , *POTENTIAL energy , *ANIMAL exoskeletons - Abstract
• A four-DoF exoskeleton with a compact three-DoF gravity compensation system. • Theoretical analysis and design of the system based on potential energy equations. • Theoretical effectiveness validation by numerical calculations in the quasi-static state. • Practical performance evaluation of the developed exoskeleton prototype. Gravity compensation (GC) mechanisms are commonly employed to either support limb gravity in passive exoskeletons or decrease motor power for safe human-robot interaction in active exoskeletons. This paper proposes a four-degree-of-freedom (DoF) upper limb exoskeleton with a theoretically perfect GC system, incorporating three DoFs in the shoulder and one DoF in the elbow. Paired with the anthropomorphic structure, the compact and adjustable GC system housed within the exoskeleton's linkages, reduces limitations on the limb's motion range and facilitates the integration of actuators for an active system. First, the GC system is designed through the analysis of potential energy equations, employing five cable-pulley-spring based units interconnected by parallel and differential mechanisms. Subsequently, the mechanical structure of the exoskeleton is developed, and the theoretically perfect GC in the quasi-static state is verified through numerical calculations. Then, the prototype is fabricated, and its actual performance is evaluated through experiments. The experimental results demonstrate the effectiveness of the exoskeleton with GC. Finally, a potential solution for the integration of actuators is demonstrated, and the limitation of the proposed system is also well discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Flexible Robots
- Author
-
De Luca, Alessandro, Baillieul, John, editor, and Samad, Tariq, editor
- Published
- 2021
- Full Text
- View/download PDF
45. Exoskeleton Based on Elastic Hinges with a Given Characteristic for Passive Gravitational Compensation of Heavy Objects
- Author
-
Zotov, A., Valeev, A., Sviridov, A., Cavas-Martínez, Francisco, Series Editor, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Haddar, Mohamed, Series Editor, Ivanov, Vitalii, Series Editor, Kwon, Young W., Series Editor, Trojanowska, Justyna, Series Editor, di Mare, Francesca, Series Editor, Radionov, Andrey A., editor, and Gasiyarov, Vadim R., editor
- Published
- 2021
- Full Text
- View/download PDF
46. Gravity Compensation of Delta Parallel Robot Using a Gear-Spring Mechanism
- Author
-
Nguyen, Vu Linh, Kuo, Chin-Hsing, Lin, Chyi-Yeu, Serafini, Paolo, Managing Editor, Guazzelli, Elisabeth, Series Editor, Rammerstorfer, Franz G., Series Editor, Wall, Wolfgang A., Series Editor, Schrefler, Bernhard, Series Editor, Venture, Gentiane, editor, Solis, Jorge, editor, Takeda, Yukio, editor, and Konno, Atsushi, editor
- Published
- 2021
- Full Text
- View/download PDF
47. Improving the Force Display of Haptic Device Based on Gravity Compensation for Surgical Robotics.
- Author
-
Jin, Lixing, Duan, Xingguang, He, Rui, Meng, Fansheng, and Li, Changsheng
- Subjects
HAPTIC devices ,GRAVITY ,SURGICAL robots ,ROBOTICS ,ELECTRIC torque motors ,GENETIC algorithms - Abstract
Haptic devices are applied as masters to provide force displays for telemedicinal robots. Gravity compensation has been proven to be crucial for the accuracy and capability of force displays, which are critical for haptic devices to assist operators. Therefore, the existing method suffers from an unsatisfactory effect, a complex implementation, and low efficiency. In this paper, an approach combining active and passive gravity compensation is proposed to improve the performance of a force display. The passive compensation is conducted by counterweights fixed with the moving platform and pantographs to offset most of the gravity and reduce the loads of the motors, while the peak capability of the force display is enhanced. The required weight is optimized by a multi-objective genetic algorithm in terms of the maximum torque of the motors in the global workspace. As a supplement, the residual gravity is eliminated by active compensation to extend the accuracy of the force display. The balancing forces in the discretized workspace are entirely calibrated, and the required force for the arbitrary configuration is calculated by interpolations. The decisions regarding the algorithm parameters are also discussed to achieve a compromise between the effect and elapsed time. Finally, the prototype with a compensation mechanism is implemented and experiments are carried out to verify the performance of the proposed method. The results show that the peak capability of the force display is enhanced by 45.43% and the maximum deviation is lowered to 0.6 N. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
48. Gravity compensation method via magnetic quasi-zero stiffness combined with a quasi-zero deformation control strategy.
- Author
-
Zhou, Rui, Zhou, YiFan, Chen, XueDong, Hou, WeiJie, Wang, Chang, Wang, Hao, and Jiang, Wei
- Abstract
Gravity compensation refers to the creation of a constant supporting force to fully or partly counteract the gravitational force for ground verification to simulate the spacecraft dynamics in outer space with zero- or micro-gravity. Gravity compensation is usually implemented via a very low stiffness suspension/supporting unit, and a servo system in series is adopted to extend the simulation range to hundreds of millimeters. The error of suspension force can be up to tens of Newton due to the contact/friction in the suspension/supporting unit and the error of the force/pressure sensor. It has become a bottleneck for the ground verification of spacecraft guidance, navigation, and control systems with extreme requirements, such as tons of payload and fine thrust in sub-Newtons. In this article, a novel gravity compensation method characterized by quasi-zero stiffness plus quasi-zero deformation (QZS-QZD) is proposed. A magnetic negative stiffness spring in parallel with positive springs and aerostatic bearing is adopted to form a QZS supporting unit, and disturbance forces, such as contact or friction, can be eliminated. The deformation of the QZS supporting unit is measured via a displacement sensor, and the QZD control strategy is applied to guarantee the force error of gravity compensation to be less than sub-newtons and irrelevant to the payload. The principle of gravity compensation with QZS-QZD is analyzed, and performance tests on a prototype are carried out. The results show that when the spacecraft moves smoothly, the absolute force error is less than 0.5 N, the relative error of gravity compensation is less than 0.1%, and when collisions with other objects occur, the relative errors are 0.32% and 0.65%. The proposed method can significantly improve the gravity compensation accuracy in comparison with conventional approaches. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
49. Design Concepts for Human Walking and Sitting Wearable Exoskeletons
- Author
-
Ghazaryan, S. D., Harutyunyan, M. G., Zakaryan, N. B., Arakelian, V., Ceccarelli, Marco, Series Editor, Hernandez, Alfonso, Editorial Board Member, Huang, Tian, Editorial Board Member, Takeda, Yukio, Editorial Board Member, Corves, Burkhard, Editorial Board Member, Agrawal, Sunil, Editorial Board Member, Misyurin, Sergey Yu., editor, Arakelian, Vigen, editor, and Avetisyan, Arutyun I., editor
- Published
- 2020
- Full Text
- View/download PDF
50. Performance Evaluation of a Class of Gravity-Compensated Gear-Spring Planar Articulated Manipulators
- Author
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Linh, Nguyen Vu, Kuo, Chin-Hsing, Ceccarelli, Marco, Series Editor, Hernandez, Alfonso, Editorial Board Member, Huang, Tian, Editorial Board Member, Takeda, Yukio, Editorial Board Member, Corves, Burkhard, Editorial Board Member, Agrawal, Sunil, Editorial Board Member, Kuo, Chin-Hsing, editor, Lin, Pei-Chun, editor, Essomba, Terence, editor, and Chen, Guan-Chen, editor
- Published
- 2020
- Full Text
- View/download PDF
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