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The specific energy of lithium-ion batteries (LIBs) can be enhanced through various approaches, one of which is increasing the proportion of active materials by thickening the electrodes. However, this typically leads to the battery having lower performance at a high cycling rate, a phenomenon commonly known as rate capacity retention. One solution to this is perforating the electrode, by creating channels or corrugations in the active electrode material, either as holes or as channels. This is known to reduce the rate capacity retention effect, but in order to engineer this better, a simplified transport process analysis needs to be established. In this paper, we propose a classic electrochemical analysis based on voltage–charge cycling measurements in order to obtain a classical mass transport coefficient, h m , that is further used as a main indicator for electrode design quality assessment. We also demonstrate theoretically and experimentally how the mass transfer coefficient, h m , can be determined and how it changes as the electrode layer thickness increases, with and without electrode corrugations. [ABSTRACT FROM AUTHOR]

Currently wearable assistive robot has been widely researched and applied in many fields. Aiming at the problems of difficult and time-consuming handling of goods, a wearable assistive robot using automatic dynamic analysis of mechanical systems is designed. The robot is assisted by robot operating system. The robot uses robot operating system to assist the automatic dynamic analysis of mechanical systems system, and the mechanical structure of the robot is analyzed and designed. Then the robot structure is simulated and analyzed by the software to explore the practical application of the robot. The results of the study indicated that the height of the robot’s air drive affected the effectiveness of the robot’s application. The angle of the robot could reach 36.2° at 0mm height, 53.6° at 50mm and 66.7° at 100mm. At the same time, the maximum force of the robot’s stand could reach 191.5N. The amount of robot’s assisting force varied in different handling goods. The actual force applied by the robot varied in different arm positions. However, the actual structural design of the robot is in line with the actual application effect. It can be concluded that the robot designed by the system conforms to the actual application structure and can realize the actual booster assistance effect. This is a good guide for the assistive control and structure analysis of the assistive robot.

The specific energy of lithium-ion batteries (LIBs) can be enhanced through various approaches, one of which is increasing the proportion of active materials by thickening the electrodes. However, this typically leads to the battery having lower performance at a high cycling rate, a phenomenon commonly known as rate capacity retention. One solution to this is perforating the electrode, by creating channels or corrugations in the active electrode material, either as holes or as channels. This is known to reduce the rate capacity retention effect, but in order to engineer this better, a simplified transport process analysis needs to be established. In this paper, we propose a classic electrochemical analysis based on voltage–charge cycling measurements in order to obtain a classical mass transport coefficient, hm, that is further used as a main indicator for electrode design quality assessment. We also demonstrate theoretically and experimentally how the mass transfer coefficient, hm, can be determined and how it changes as the electrode layer thickness increases, with and without electrode corrugations.

Mobile robotics has been used in recent years to provide various types of services in fields such as agriculture, surveillance, rehabilitation, space exploration, and logistics, among others. In many cases, mobile robots need to overcome complex obstacles where traditional wheels are not the best solution, and many researchers have proposed legged wheel hybrid designs. This paper presents a comprehensive study on the effect of the geometry of legged wheels on the performance of mobile robots in climbing stairs. The method used to develop this research is dynamic simulation, in which the parameters that affect the kinematics and dynamics of the robot are included. Subsequently, the results of how the robot manages to perform the test, the torque of the motors, and the contact force of the wheels are analyzed. The main hypothesis of this research is that the opening of the legs of the wheels is a geometric parameter that determines whether the structure will be able to climb the stairs. After 63 simulations, the proportional relationship between the diagonal of the stands and the opening of the wheel legs ranges between 1.11 and 1.53. This parameter showed a strong correlation with the torque of the motors and significant differences in terms of the simulations that succeeded in climbing the stairs and those that did not. These results were used to state a design method for flat, robotic structures using legged wheels. This method was validated by an additional simulation that was performed for a four-legged wheel. It can be concluded that the contribution of this work is a series of steps with which to design these mechanical structures to climb the stairs based on the proposed indicator. [ABSTRACT FROM AUTHOR]

In recent times, the soft robotics field has been attracting significant research focus owing to its high level of manipulation capabilities unlike traditional rigid robots, which gives room for increasing use in other areas. However, compared to traditional rigid gripper robots, being capable of controlling/obtaining overall body stiffness when required is yet to be further explored since soft gripper robots have inherently less-rigid properties. Unlike previous designs with very complex variable-stiffness systems, this paper demonstrates a soft gripper design with minimum system complexity while being capable of varying the stiffness of a continuum soft robotic actuator and proves to have potential applications in gripping objects of various shapes, weights, and sizes. The soft gripper actuator comprises two separate mechanisms: the pneumatic mechanism for bending control and the mechanical structure for stiffness variation by pulling tendons using stepper motors which compresses the actuator, thereby changing the overall stiffness. The pneumatic mechanism was first fabricated and then embedded into another silicon layer during which it was also merged with the mechanical structure for stiffness control. By first pneumatically actuating the actuator which causes bending and then pulling the tendons, we found out that the actuator stiffness value can be increased up to 145% its initial value, and the gripper can grasp and lift a weight of up to 2.075 kg. [ABSTRACT FROM AUTHOR]

Compared with finite element method (FEA) and statistical energy method (SEA), the energy finite element method (EFEA) is a promising and more suitable method to predict the highfrequency vibration response and radiated noise of mechanical structures, due to its advantages of both computational efficiency and ability to get detail information. In recent years, researchers have made great progress in EFEA, due to the urgency of engineering application. This paper aims to comprehensively summarize historical and latest development of energy finite element analysis from two aspects of theory and engineering, to furtherly promote its application in the engineering field. Firstly, the development history of EFEA in basic structures is summarized, and the theoretical development direction of energy finite element in recent years is further analyzed. After that, the application of EFEA in aerospace, ship and vehicle engineering are summarized. Finally, the problems that need to be furtherly studied in EFEA are presented, and it is pointed out that it is an urgent research work to continue to improve the energy finite element analysis theory and software and apply it to engineering. [ABSTRACT FROM AUTHOR]

Recently, as humans have become increasingly interested in ocean resources, underwater vehicle-manipulator systems (UVMSs) have played an increasingly important role in ocean exploitation. To realize precise operation in underwater narrow spaces, the fly arm underwater vehicle manipulator system (FAUVMS) is proposed with manipulators as its core. However, this system suffers severe dynamic coupling effects due to the combination of small vehicle and big manipulators. To resolve this issue, we propose a robust adaptive controller that contains two parts. In the first part, the extended Kalman filter (EKF) is designed to estimate the system states and predicts external disturbances to achieve adaptive control. In the second part, a chattering-free sliding mode control (SMC) is designed to converge the tracking errors to zero, thus guaranteeing the robustness of the controller. We constructed the simulation platform based on the geometric model of FAUVMS, and various simulations are carried out under different situations. Compared to the traditional methods, the proposed method has a faster convergent speed, a better robustness and adaptiveness to external disturbances, and the tracking errors of positions of the vehicle and each end-effector are much smaller. [ABSTRACT FROM AUTHOR]

The accurate measurement of mass and centroid is indispensable for accurate control of aircraft. In order to eliminate the influence of assembly error and product pose error on the measurement results, a multi-station measurement idea that can self-compensate for the geometric parameter error is proposed in this paper based on. At the same time, the kinematic model of the mechanical structure of the measurement equipment is established to prove the effectiveness of the structure in error compensation theoretically, and the experimental verification of the standard part and aircraft is carried out. The test results show that the measurement results using the idea of the multi-station compensation measurement are significantly better than those of the more common methods, with the mass measurement accuracy of 0.03% and the centroid error within ±0.15 mm, meeting the requirement of high precision measurement for the mass properties. [ABSTRACT FROM AUTHOR]

In this paper, we present a numerical design of a pressure sensor using surface plasmon resonance (SPR) based on Fabry–Perot interferometer mechanism with focus on MoS2 and graphene monolayer nanomaterials. These two-dimensional nanomaterials increase the sensitivity of the device. The proposed sensor consists of two parts: mechanical structure and SPR detection part, both of which have been examined. Sensing range of the proposed sensor is 0–160 MPa with a sensitivity of 300 nm/GPa. By making a theoretical link between mechanical structure and optical detection parts, we have completely simulated the sensor and evaluated the results. The pressure sensitivity of the MoS2 monolayers can provide an opportunity for nanoscale pressure sensors as well as applications in electronic, flexible, and nano-electronic devices. We used of FDTD method for the optical section and FEM method for the mechanical structure to evaluate the performance of the proposed sensor. [ABSTRACT FROM AUTHOR]

Mobile robotics has been used in recent years to provide various types of services in fields such as agriculture, surveillance, rehabilitation, space exploration, and logistics, among others. In many cases, mobile robots need to overcome complex obstacles where traditional wheels are not the best solution, and many researchers have proposed legged wheel hybrid designs. This paper presents a comprehensive study on the effect of the geometry of legged wheels on the performance of mobile robots in climbing stairs. The method used to develop this research is dynamic simulation, in which the parameters that affect the kinematics and dynamics of the robot are included. Subsequently, the results of how the robot manages to perform the test, the torque of the motors, and the contact force of the wheels are analyzed. The main hypothesis of this research is that the opening of the legs of the wheels is a geometric parameter that determines whether the structure will be able to climb the stairs. After 63 simulations, the proportional relationship between the diagonal of the stands and the opening of the wheel legs ranges between 1.11 and 1.53. This parameter showed a strong correlation with the torque of the motors and significant differences in terms of the simulations that succeeded in climbing the stairs and those that did not. These results were used to state a design method for flat, robotic structures using legged wheels. This method was validated by an additional simulation that was performed for a four-legged wheel. It can be concluded that the contribution of this work is a series of steps with which to design these mechanical structures to climb the stairs based on the proposed indicator.

In recent times, the soft robotics field has been attracting significant research focus owing to its high level of manipulation capabilities unlike traditional rigid robots, which gives room for increasing use in other areas. However, compared to traditional rigid gripper robots, being capable of controlling/obtaining overall body stiffness when required is yet to be further explored since soft gripper robots have inherently less-rigid properties. Unlike previous designs with very complex variable-stiffness systems, this paper demonstrates a soft gripper design with minimum system complexity while being capable of varying the stiffness of a continuum soft robotic actuator and proves to have potential applications in gripping objects of various shapes, weights, and sizes. The soft gripper actuator comprises two separate mechanisms: the pneumatic mechanism for bending control and the mechanical structure for stiffness variation by pulling tendons using stepper motors which compresses the actuator, thereby changing the overall stiffness. The pneumatic mechanism was first fabricated and then embedded into another silicon layer during which it was also merged with the mechanical structure for stiffness control. By first pneumatically actuating the actuator which causes bending and then pulling the tendons, we found out that the actuator stiffness value can be increased up to 145% its initial value, and the gripper can grasp and lift a weight of up to 2.075 kg.

The field mobile platform is an important tool for high-throughput phenotype monitoring. To overcome problems in existing field-based crop phenotyping platforms, including limited application scope and low stability, a rolling adjustment method for the wheel tread was proposed. A self-propelled three-wheeled field-based crop phenotyping platform with variable wheel tread and height above ground was developed, which enabled phenotypic information of different dry crops in different development stages. A three-dimensional model of the platform was established using Pro/E; ANSYS and ADAMS were used for static and dynamic performance. Results show that when running on flat ground, the platform has a vibration acceleration lower than 0.5 m/s2. When climbing over an obstacle with a height of 100 mm, the vibration amplitude of the platform is 88.7 mm. The climbing angle is not less than 15°. Field tests imply that the normalized difference vegetation index (NDVI) and the ratio vegetation index (RVI) of a canopy measured using crop growth sensors mounted on the above platform show favorable linear correlations with those measured using a handheld analytical spectral device (ASD). Their R2 values are 0.6052 and 0.6093 and root-mean-square errors (RMSEs) are 0.0487 and 0.1521, respectively. The field-based crop phenotyping platform provides a carrier for high-throughput acquisition of crop phenotypic information. [ABSTRACT FROM AUTHOR]

Recently, as humans have become increasingly interested in ocean resources, underwater vehicle-manipulator systems (UVMSs) have played an increasingly important role in ocean exploitation. To realize precise operation in underwater narrow spaces, the fly arm underwater vehicle manipulator system (FAUVMS) is proposed with manipulators as its core. However, this system suffers severe dynamic coupling effects due to the combination of small vehicle and big manipulators. To resolve this issue, we propose a robust adaptive controller that contains two parts. In the first part, the extended Kalman filter (EKF) is designed to estimate the system states and predicts external disturbances to achieve adaptive control. In the second part, a chattering-free sliding mode control (SMC) is designed to converge the tracking errors to zero, thus guaranteeing the robustness of the controller. We constructed the simulation platform based on the geometric model of FAUVMS, and various simulations are carried out under different situations. Compared to the traditional methods, the proposed method has a faster convergent speed, a better robustness and adaptiveness to external disturbances, and the tracking errors of positions of the vehicle and each end-effector are much smaller.

The accurate measurement of aircraft mass properties, such as the mass, centroid, and moment of inertia (MOI), plays a key role in the precise control of aircraft. In order to obtain high-precision information on the parameters of the mass, centroid, and MOI of an aircraft using a single instrument, an integrated mass property measurement system was developed in this study by analyzing and comparing the latest technologies, especially the function-switching device, which switches the measurement states between the center of mass and the MOI. The purpose of mass property measurement was achieved through single clamping. In addition, the system has strong versatility and expansion and can be used with different tooling or adapter rings to measure the mass properties of aircraft with different shapes. In this paper, the main mechanical structure of the measurement system, the measurement method of relevant mass parameters, and the solution method of the transformation matrix are introduced, and the standard parts and the aircraft were verified experimentally. The test results showed that the mass measurement accuracy was 0.03%, the centroid measurement error was within ±0.2 mm, and the measurement accuracy of the MOI was within 0.2%, all of which meet the high-precision measurement requirements for the mass properties. [ABSTRACT FROM AUTHOR]

Studying the motion and load-bearing characteristics of the planetary roller screw mechanism is the basis for the structural design and performance optimisation of the mechanism. The mechanical structures and working principles of different kinds of planetary roller screw mechanisms are summarised. Published papers on kinematic, load-bearing and dynamic models of the planetary roller screw mechanism are reviewed. Based on the slip state in point contacts at the screw–roller and the nut–roller interfaces, the kinematic models are divided into three types. The finite element method and numerical theory are the two main methods used to develop the load-bearing models. Current dynamic models differ mainly concerning whether they take the rotation of the screw into consideration. In this work, each kind of model is presented in detail along with relevant literature. The main conclusions for each type of model are discussed, and an overview of the future evolution of motion and load-bearing characteristics of the planetary roller screw mechanism are given. [ABSTRACT FROM AUTHOR]

The accurate measurement of mass and centroid is indispensable for accurate control of aircraft. In order to eliminate the influence of assembly error and product pose error on the measurement results, a multi-station measurement idea that can self-compensate for the geometric parameter error is proposed in this paper based on. At the same time, the kinematic model of the mechanical structure of the measurement equipment is established to prove the effectiveness of the structure in error compensation theoretically, and the experimental verification of the standard part and aircraft is carried out. The test results show that the measurement results using the idea of the multi-station compensation measurement are significantly better than those of the more common methods, with the mass measurement accuracy of 0.03% and the centroid error within ±0.15 mm, meeting the requirement of high precision measurement for the mass properties.

The field mobile platform is an important tool for high-throughput phenotype monitoring. To overcome problems in existing field-based crop phenotyping platforms, including limited application scope and low stability, a rolling adjustment method for the wheel tread was proposed. A self-propelled three-wheeled field-based crop phenotyping platform with variable wheel tread and height above ground was developed, which enabled phenotypic information of different dry crops in different development stages. A three-dimensional model of the platform was established using Pro/E; ANSYS and ADAMS were used for static and dynamic performance. Results show that when running on flat ground, the platform has a vibration acceleration lower than 0.5 m/s2. When climbing over an obstacle with a height of 100 mm, the vibration amplitude of the platform is 88.7 mm. The climbing angle is not less than 15°. Field tests imply that the normalized difference vegetation index (NDVI) and the ratio vegetation index (RVI) of a canopy measured using crop growth sensors mounted on the above platform show favorable linear correlations with those measured using a handheld analytical spectral device (ASD). Their R2 values are 0.6052 and 0.6093 and root-mean-square errors (RMSEs) are 0.0487 and 0.1521, respectively. The field-based crop phenotyping platform provides a carrier for high-throughput acquisition of crop phenotypic information.

Global warming had been a serious issue these recent years, the use of alternative energy sources such as solar energy are being more important. To make it more feasible, the efficiency of solar modules must increase. Sun tracking system is one of the methods to increase efficiency. In this paper, design and fabrication of a low cost Dual Axis Solar Tracker (DAST) is proposed. The DAST and control system that control the movement of solar panel to ensure it is always perpendicular to the sun are discussed. The DAST system is a hardware and software system that automatically tracks the sun's location during the day. For optimum performance, make sure it's in the best possible position with the sun. When compared to a static solar panel, DAST has been found to provide 16 percent more power output. The low cost mechanical structure has been fabricated and stress analysis had been performed. Rotation axis is control by stepper motor with pulley and belt, while the elevation is control by a linear actuator. It is proved that the low cost mechanical structure design can be used for automatic tracking system along with electronic design. [ABSTRACT FROM AUTHOR]

In the framework of the U.S. Magnet Development Program (MDP), Fermilab has developed and tested a high-field Nb3Sn dipole demonstrator MDPCT1 for a post-LHC Hadron Collider. The magnet was first assembled with a lower coil pre-load to minimize the risk of coil damage during assembly and test. In the first test the magnet reached its test goal producing a world record field of 14.1 T at 4.5 K. Next the magnet was reassembled with nominal pre-load to achieve its design field limit of 15 T. This paper describes the details of MDPCT1 inspection, design modifications and reassembly. The magnet quench performance, including training, ramp rate and temperature dependences in the temperature range of 1.9-4.5 K, is presented and discussed. [ABSTRACT FROM AUTHOR]

In this study, unmanned aerial vehicles (UAVs) were classified based on the principle of generation of lifting force. In addition, the structural characteristics, flight mechanisms, and research examples of each UAV category were introduced. Lifting force is the force that enables an aircraft to hover by countering gravity. It is one of the four forces (i.e., gravity, lifting force, thrust force, and drag force) that act on an aircraft while it flies. In this study, UAVs were classified into the following four categories based on the method of generation of lifting force: (1) fixed wing-based UAVs, which fly based on the lifting force generated indirectly from the forward thrust by using the geometry of aerodynamically designed fixed-wing cross-sections; (2) rotating and flapping wing-based UAVs, which generate lifting force directly using rotating or reciprocating wings, to counter gravity; (3) hybrid wing-based UAVs, which fly using both fixed and rotating wings; and (4) gas envelope-based UAVs, which generate lifting force using the difference in density between the gas and external air, rather than wings. These four types were classified further based specifically on the structural characteristics, and described using particular cases. Considering that UAVs have various flight purposes such as material transport, reconnaissance, surveillance, and special operations, it is anticipated that UAVs with the optimal flight mechanism for each purpose can be selected based on the flight characteristics of UAVs introduced in this paper. [ABSTRACT FROM AUTHOR]

The accurate measurement of aircraft mass properties, such as the mass, centroid, and moment of inertia (MOI), plays a key role in the precise control of aircraft. In order to obtain high-precision information on the parameters of the mass, centroid, and MOI of an aircraft using a single instrument, an integrated mass property measurement system was developed in this study by analyzing and comparing the latest technologies, especially the function-switching device, which switches the measurement states between the center of mass and the MOI. The purpose of mass property measurement was achieved through single clamping. In addition, the system has strong versatility and expansion and can be used with different tooling or adapter rings to measure the mass properties of aircraft with different shapes. In this paper, the main mechanical structure of the measurement system, the measurement method of relevant mass parameters, and the solution method of the transformation matrix are introduced, and the standard parts and the aircraft were verified experimentally. The test results showed that the mass measurement accuracy was 0.03%, the centroid measurement error was within ±0.2 mm, and the measurement accuracy of the MOI was within 0.2%, all of which meet the high-precision measurement requirements for the mass properties.

Studying the motion and load-bearing characteristics of the planetary roller screw mechanism is the basis for the structural design and performance optimisation of the mechanism. The mechanical structures and working principles of different kinds of planetary roller screw mechanisms are summarised. Published papers on kinematic, load-bearing and dynamic models of the planetary roller screw mechanism are reviewed. Based on the slip state in point contacts at the screw–roller and the nut–roller interfaces, the kinematic models are divided into three types. The finite element method and numerical theory are the two main methods used to develop the load-bearing models. Current dynamic models differ mainly concerning whether they take the rotation of the screw into consideration. In this work, each kind of model is presented in detail along with relevant literature. The main conclusions for each type of model are discussed, and an overview of the future evolution of motion and load-bearing characteristics of the planetary roller screw mechanism are given.

Fiber optic gyroscope (FOG) is a new type of optical sensor used to measure the rotating angular velocity. As the core component, fiber optic coil (FOC) plays a decisive role in the FOG output precision. The manufacturing level and efficiency of FOC have been main factors restricting the application and development of high precision FOG. Precision mechanical positioning method based on the photoelectric devices was researched, and high-performance fully automatic micro mechanical error compensation technique was developed. On these basis. automatic fiber distribution and winding control technology were realized. Eventually a multifunctional system was developed with fiber splitting module, fiber winding module, and calibration module. This system could accomplish automatic preparation of FOC with quadrupolar symmetric pattern according to the parameters set by user. The principle and working flow of each functional module are discussed in details. Experiments show that the system can achieve automatic speed changing, automatic reversing, constant small tension control and precise fiber arrangement. The new designed system greatly improve FOC production efficiency and is conductive to promoting high level FOG development. [ABSTRACT FROM AUTHOR]

The traditional bionic upper limb structure design is limited by the motion pair and cannot guarantee the flexibility of the mechanical structure. The tensegrity structure has the characteristics of high deformability, strong self-adaptability, and resistance to multi-directional impact. According to the biological characteristics of the upper limbs of the human body, an anatomical study is performed on the upper limb wrist joints that achieve adduction/abduction, flexion/extension, to obtain the relationship between the movements of the related bones and muscles, and to simplify the shape and structure of the wrist. Equivalent mapping of a mechanical model based on two-bar tensile properties. Through the contraction and stretching of the spring, the movement characteristics of the human muscles are realised, and the optimised bionic upper limb wrist tensioning robot without motion pair is further obtained. Adams simulation is used to verify that the bionic tensile wrist can simulate the change movement of the human wrist. The experimental platform was built and a physical prototype was made and the prototype was tested. The results show that the bionic tensile wrist can realise the adaptive motion characteristics of the human wrist well and stably, which proves the validity and feasibility of this design method.

The end-effector is a key device for direct contact and operation between the operator and the workpiece, and its mechanical structure will directly affect the quality of the machine and expand its application. The theoretical research and technical implementation of the end-effector for compliance control are facing a lot of urgent challenges to be solved, therefore, the research results of active compliance control of robot end-effectors have a very broad application prospect. This paper describes the design and research results of different end-effectors under impedance-based control, hybrid force/position control, and intelligent flexible control methods, respectively. Under each control method, the structural characteristics and the optimized control scheme under different drives are introduced. Finally, key techniques for achieving compliance control are derived by summarizing, which broadens the engineering applications and provides methods and ideas for future research.

The first part of the paper presents the topological structure of the horse skeleton, highlighting the tubular architecture of long bones that is mechanically conditioned by the stresses to which the bone is subjected during walking. The mechanical structure of the bone acts as reinforced concrete, consisting of the fibrillated fundamental matter, molecularly embedded by lime salts. The muscle structure of the same-side horse limbs (anterior and posterior) is pointed out. The muscles are the actuators that allow the movement and coordination of the movement of each horse leg. In the second part of the paper two models of constructive schemes of the anterior and posterior limbs have been considered. The kinematic schemes of the two articulated planar models have been achieved. The topological structure of each kinematic scheme has been analyzed by highlighting the consisting kinematic elements, the specific kinematic joints, and by confirming the degree of mobility using an original formula.

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Legged robots suffer from the impact due to the consistent collisions with the ground. At the moment of collision, the sudden impact force not only causes the legs to lose contact off the ground, but can also reduce controllability and durability. This phenomenon becomes worse for the robots in running. In order to mitigate such an impact effectively, this study focuses on the mechanical structure of the legs, unlike the previous studies, which focused on the component level. The mechanical structures include actuator configuration, segment ratio, total length, and flexion direction. Contact inertia (CI), closely related to the impact, is derived and utilized to analyze the mechanical structure in terms of impact mitigation. A series of impact experiments with a fabricated leg verify that the mechanical structure affects mitigating the impact. [ABSTRACT FROM AUTHOR]

Featured Application: This novel robot could be applied in hospital, family and nursing home to help the elderly complete the basic daily activities and move patient autonomously. Life care for disabled or semi-disabled elderly has become an increasingly common problem in society. In this paper, a novel wheelchair-stretcher assistive robot, which can meet the physiological needs of patients, is investigated and designed. The following tasks are conducted: (1) the mecanum wheel is adopted as the executive device of the walking mechanism, and its kinematics is analyzed in detail. (2) A five-link mechanism with single degree of freedom is proposed to realize the folding motion of the robot. Through the minimum conclusive area method, the optimal sizes of the armrests link and the side link are 507.9, and 332.5 mm, respectively. Based on the force analysis of the linkage mechanism, six torsion springs and RV (rotate vector) reduction motor are used as the driving device, which reduces the driving torque of the motor. (3) Based on the STM32 (STMicroelectronics 32-bits Microcontroller) chip, and combined with the theoretical analysis, the mechanical structure and the control system of the whole prototype are designed, and the feasibility of each module is verified by experimental research. The results confirm that the proposed robot has good performance, and that the control algorithm for the walking mechanism and the lifting mechanism are suitable. [ABSTRACT FROM AUTHOR]

Symmetry widely exists in natural objects and man-made objects. Mechanical structures, as man-made objects, have the property of symmetry without exception. The existence of symmetry affects the function and performance of mechanical products. Therefore, on the basis of analyzing a large number of examples and referring to the Schoenflies symbol of crystal, the symmetry of mechanical structures is divided into point group symmetry and space group symmetry, and these two types are further subdivided according to the types and spatial positions of the symmetry elements. Then, the general effects of symmetry are summarized according to symmetry types and functions, and several symmetry rules for design are further refined. Finally, after defining the requirements of speed change and technology background, a multispeed device for bicycle shaft drive is proposed by applying symmetry knowledge comprehensively.

Measuring the mass and Center of Gravity (CG) of rigid bodies with a multi-point weighing method is widely used nowadays. Traditional methods usually include two parts with a certain location, i.e., a fixed platform and a mobile platform. In this paper, a novel structure is proposed to adjust the mobile platform for eliminating side forces which may load on the load cells. In addition, closed-form equations are formulated to evaluate the performance of the structure, and transformation matrices are used to estimate the characteristics of the structure. Simulation results demonstrate that repeatability of the proposed structure is higher than the traditional one and there are no side forces. Moreover, the measurement results show that the relative error of mass was within 0.05%, and the error of CG was within ±0.3 mm. The structure presented in this paper provides a foundation for practical applications. [ABSTRACT FROM AUTHOR]

One research direction for future synchrotron light sources is the development of elliptically polarized undulators (EPUs) with a short period and high magnetic field. The Shanghai Synchrotron Radiation Facility (SSRF) has developed a compact EPU prototype with a 16 mm period. The prototype incorporates a novel magnetic structure consisting of 8 magnet arrays, generating a peak magnetic field reaching approximately 0.8 T. Additionally, the magnetic structure is compact and lightweight, featuring a 5 mm aperture (ϕ 5 mm). To assess its performance, the magnetic field was measured using the pulsed wire and Hall sensor methods. This paper presents a detailed analysis of the physical design, mechanical structure, and measurement results of the compact EPU prototype. [ABSTRACT FROM AUTHOR]

There are numerous thrust fault-related landforms widely distributed on the surface of Mercury. Geomorphic interpretations suggest that these landforms are either thin or thick-rooted, reflecting the mechanical structure of Mercury's lithosphere. In this work, we propose a mechanical model incorporating brittle, semi-brittle, and viscous deformation mechanisms to depict the mechanical and strength profile of Mercury's lithosphere, where the effective elastic thickness is about 30 km. To investigate which and how parameters control the lithospheric mechanical structure, we apply the random forest algorithm to select features by predicting the deformation mechanism with given sets of randomly generated input parameters, suggesting that the lithospheric viscosity, depth, and rheological model are the most important parameters. On this basis, we discuss how the viscosity and rheological model react to the changes in temperature, strain rates, and creep laws. Our results indicate that lowering the temperature or increasing the strain rate result in an increased strength profile and expanded regions where brittle and semi-brittle deformation occurs in the lithosphere. Qualitative analyses of the importance of Peierls, dislocation, and diffusion creeps in forming the rheological structure are conducted by applying multivariate regression analysis. It shows that Peierls creep dominates and stabilizes the rheological structure in the shallow depth due to its strong stress dependence for low temperatures. Moreover, the rheological model involving Peierls creep results in a reduced strength profile and simpler mechanical structure. Therefore, we emphasize that the Peierls creep is shown to be also critical in determining the strength and mechanical structure of Mercury in addition to temperature and strain rate. • A mechanical model incorporating semi-brittle mechanism to study the deformation of Mercury's lithosphere is proposed. • The key parameters determining the mechanical structure of the lithosphere are investigated by Machine-learning algorithms. • The Peierls creep is shown to be critical in determining the shallow lithospheric structure of Mercury. [ABSTRACT FROM AUTHOR]

The U.S. Magnet Development Program (US-MDP) is aimed at developing high-field accelerator magnets with magnetic fields beyond the limits of Nb3Sn technology. Recent progress with composite wires and Rutherford cables based on the first generation high-temperature superconductor Bi2Sr2CaCu2O8−x (Bi2212) allows considering them for this purpose. However, Bi2212 wires and cables are sensitive to transverse stresses and strains, which are large in high-field accelerator magnets. This requires magnet designs with stress management concepts to control azimuthal and radial strains in the coil windings and prevent the degradation of the current carrying capability of Bi2212 conductor or even its permanent damage. This paper describes a novel stress management approach, which was developed at Fermilab for high-field large-aperture Nb3Sn accelerator magnets, and is now being applied to high-field dipole inserts based on Bi2212 Rutherford cables. The insert conceptual design and main parameters, including the superconducting wire and cable, as well as the coil stress management structure, key technological steps and approaches, test configurations and their target parameters, are presented and discussed.

Legged robots suffer from the impact due to the consistent collisions with the ground. At the moment of collision, the sudden impact force not only causes the legs to lose contact off the ground, but can also reduce controllability and durability. This phenomenon becomes worse for the robots in running. In order to mitigate such an impact effectively, this study focuses on the mechanical structure of the legs, unlike the previous studies, which focused on the component level. The mechanical structures include actuator configuration, segment ratio, total length, and flexion direction. Contact inertia (CI), closely related to the impact, is derived and utilized to analyze the mechanical structure in terms of impact mitigation. A series of impact experiments with a fabricated leg verify that the mechanical structure affects mitigating the impact.

Life care for disabled or semi-disabled elderly has become an increasingly common problem in society. In this paper, a novel wheelchair-stretcher assistive robot, which can meet the physiological needs of patients, is investigated and designed. The following tasks are conducted: (1) the mecanum wheel is adopted as the executive device of the walking mechanism, and its kinematics is analyzed in detail. (2) A five-link mechanism with single degree of freedom is proposed to realize the folding motion of the robot. Through the minimum conclusive area method, the optimal sizes of the armrests link and the side link are 507.9, and 332.5 mm, respectively. Based on the force analysis of the linkage mechanism, six torsion springs and RV (rotate vector) reduction motor are used as the driving device, which reduces the driving torque of the motor. (3) Based on the STM32 (STMicroelectronics 32-bits Microcontroller) chip, and combined with the theoretical analysis, the mechanical structure and the control system of the whole prototype are designed, and the feasibility of each module is verified by experimental research. The results confirm that the proposed robot has good performance, and that the control algorithm for the walking mechanism and the lifting mechanism are suitable.

Herein, the authors review the self-regulation system secured by well-designed hybrid materials, composites, and complex system. As a broad concept, the self-regulated material/system has been defined in a wide research field and proven to be of great interest for use in a biomedical system, mechanical system, physical system, as the fact of something such as an organisation regulating itself without intervention from external perturbation. Here, they focus on the most recent discoveries of self-regulation phenomenon and progress in utilising the self-regulation design. This paper concludes by examining various practical applications of the remarkable materials and systems including manipulation of the oil/water interface, cell out-layer structure, radical activity, electron energy level, and mechanical structure of nanomaterials. From material science to bioengineering, self-regulation proves to be not only viable, but increasingly useful in many applications. As part of intelligent engineering, self-regulatory materials are expected to be more used as integrated intelligent components.

This paper discusses a simplified design of Humanoid Robot with 3 DOF. The main objective is to analyze the theoretical and practical challenges involved in making it. The paper emphasis bringing down the control complexity by reducing the number of actuators used, three, one for each degree of freedom. . This in turn simplifies the entire design processes and reduces the production cost. It also describes the stability issues and different walking phases in detail. The proposed robot can be placed between simple, miniaturized humanoids and the most advanced, sophisticated humanoids. The humanoid robot is programmed to go forward, backward, to rotate, to stop when it encounters obstacles. He uses two sensors: one touch, which works as a command button and one ultrasonic which determines the distance to objects.

Wang, L. and Qin, J., 2018. Flow curve optimization design for offshore backfilling plough fenders. In: Ashraf, M.A. and Chowdhury, A.J.K. (eds.), Coastal Ecosystem Responses to Human and Climatic Changes throughout Asia. Offshore backfilling ploughs are used to backfill when laying pipelines in seabed trenches, and fenders primarily consist of an offshore backfilling plough. Research on the flow curve of the fenders is essential to decrease the working resistance of the plough during backfilling. In this work, uniflow fluid–structure interaction is developed to investigate the joint forces of the fenders under different flow curves with different working condition. An onshore field study was carried out to validate the reliability of the curve. In terms of the force of the fender, the simulation results for the fender agree with the onshore field results within a certain range of trend. To analysis of the resulting data, a better flow curve for offshore backfilling plough fenders was found. [ABSTRACT FROM AUTHOR]

The paper presents a procedure to precisely estimate the natural frequencies of structures. It implies the acoustic excitation of the structure and the evaluation of the frequencies from the response signals, involving an advanced method developed by the authors. The study is performed on a cantilever beam. To demonstrate the efficiency of the contrived procedure, the values of the frequencies by applying this procedure are compared whit those obtained by standard frequency estimation made for the response to an impulsive excitation. [ABSTRACT FROM AUTHOR]

The first part of the paper presents the topological structure of the horse skeleton, highlighting the tubular architecture of long bones that is mechanically conditioned by the stresses to which the bone is subjected during walking. The mechanical structure of the bone acts as reinforced concrete, consisting of the fibrillated fundamental matter, molecularly embedded by lime salts. The muscle structure of the same-side horse limbs (anterior and posterior) is pointed out. The muscles are the actuators that allow the movement and coordination of the movement of each horse leg. In the second part of the paper two models of constructive schemes of the anterior and posterior limbs have been considered. The kinematic schemes of the two articulated planar models have been achieved. The topological structure of each kinematic scheme has been analyzed by highlighting the consisting kinematic elements, the specific kinematic joints, and by confirming the degree of mobility using an original formula. [ABSTRACT FROM AUTHOR]

It was declared [E. Yu. Klimenko, "Large superconducting magnets for transportation," in Proc. 19 Int. Conf. Electron. Commerce, Grenoble, 2002, pp. 275-278] that large superconducting windings would be saved from current degradation resulting from mechanical perturbations, if the winding had a strong and rigid supporting structure, and each turn is rigidly fixed for transmitting its force directly to the structure. The superconductor itself should not be used as a structural material. Many years ago an option was proposed that implements this principle. That is so-called laminar winding. The supporting structure consists of a set of flat sheets. A flexible conductor is bonded to the sheets with a layer of strong adhesive. This type of windings was successfully used for a long time. Additional functions of the sheets were cooling and protecting of the windings. Application of a film adhesive VK-36 provides dry manufacturing process. The article describes an assessment of very large laminar winding similar in parameters to ITER central solenoid, as one of possible application of the principle. [ABSTRACT FROM AUTHOR]

Optimisation work has been increasingly directed at commercial vehicles to reduce their weight and thus enhance their performance. This optimisation, which responds to the requirements of various European standards with regard to the reduction of fuel consumption, also involves the elements mounted on these vehicles. This work discusses the development and design of a firefighting vehicle tank made from plastic material instead of the usual structure or stainless steel, essentially to reduce the weight of the structure. The design and construction feasibility of the components have been developed based on the specifications required. These specifications concern the tank capacity to resist at different load conditions and avoid any external vibrations. To ensure this, the tank consists of a number of internal welded plates in order to reduce the sloshing effect and secondly makes it modular and thus highly adaptable to the customer's needs. Specific method on the production of the component is also provided. Therefore, numerical tests were conducted with linear elastic stress analysis with square brick elements. The boundary conditions applied to the numerical model provide a complete support to the panels and are determined by the load condition of fluid used. This preliminary analysis was conducted to define the thickness of the tank panels and revealed that the use of a plastic tank leads to a weight reduction of about 35% and generates cost savings of about 25-30% compared to the steel equivalent. Therefore, the use of plastic materials compared to the classic materials seems to be very positive and this is critical information to support the final decision in a regulated sector, where the firefighting vehicles are. [ABSTRACT FROM AUTHOR]

Measuring the mass and Center of Gravity (CG) of rigid bodies with a multi-point weighing method is widely used nowadays. Traditional methods usually include two parts with a certain location, i.e., a fixed platform and a mobile platform. In this paper, a novel structure is proposed to adjust the mobile platform for eliminating side forces which may load on the load cells. In addition, closed-form equations are formulated to evaluate the performance of the structure, and transformation matrices are used to estimate the characteristics of the structure. Simulation results demonstrate that repeatability of the proposed structure is higher than the traditional one and there are no side forces. Moreover, the measurement results show that the relative error of mass was within 0.05%, and the error of CG was within ±0.3 mm. The structure presented in this paper provides a foundation for practical applications.