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This paper addresses the limitations of camera-based random bin picking (RBP) strategies by proposing an innovative strategy that relies solely on a 6-axis load cell instead of cameras and image processing algorithms. Specific applications of RBP include loading and unloading industrial assembly machines, transferring objects between industrial workstations, and picking objects to be assembled directly. Camera-based RBP systems are limited in industrial settings due to challenges related to image processing robustness, high costs of hardware and software, the need for 3D models and extensive training datasets. These limitations are inherently tied to the reliance on camera-based technology and image processing AI. This paper presents a novel camera-less RBP strategy, eliminating the need for visual information processing altogether and circumventing these limitations. The strategy is largely agnostic to factors such as bin size, object material and gripper size, and as such can be modularly configured to the user's needs. This strategy is demonstrated using a collaborative robot, highlighting the advantages in a collaborative environment. The proposed strategy is evaluated through feasibility case studies on several objects of different geometries, namely navel oranges, cardboard boxes and resin bottles, and performance metrics are benchmarked. The strategy has an average success rate of 99%, average cycle time of 26.08 seconds per object and an average grip success rate of 47%. [ABSTRACT FROM AUTHOR]

In the context of teleoperated surgical robots, much research has been conducted into haptic feedback systems. Ultrasonic motors (USMs) are expected to be used as actuators for generating feedback torque because of their fast response and high torque–weight ratio. However, their nonlinear characteristics make control of the output torque difficult, leading to large spike-like torque errors during rotation reversal. One approach to counteracting this effect is to use series elastic actuators (SEAs). In this study, a force feedback system using an SEA with a USM was proposed. The spike-shaped errors in the output torque of the USM were reduced by up to 60 % by attaching an SEA to its output shaft. The dependence of the torque accuracy and the response time of the SEA on its spring constant were also examined. By introducing the SEA with a spring constant of 42.4 mN·m/°, it was indicated that the torque error of 14.8 mN·m and the response time of 9 ms could be simultaneously achieved. Finally, the force feedback system was applied to a teleoperated surgical robot, and the stiffness of the objects grasped by the robot was successfully fed back with the error of 0.65 % when grasping a sponge. [Display omitted] • A series elastic actuator with an ultrasonic motor was applied to a force feedback system of a teleoperated surgical robot. • Introduction of the elastic mechanism reduced the spike-like error of the output torque of the ultrasonic motor. • Calculated and experimental results matched for the response time of the torque control of the series elastic actuator. • Force feedback system using the series elastic mechanism with the ultrasonic motor realized accurate stiffness feedback. [ABSTRACT FROM AUTHOR]

Teleoperation technology has become a feasible solution for the mobile manipulator to carry out complex tasks in remote environments, with its advantages of mobility and manipulability. However, due to the high redundancy of the mobile manipulator, its application in the field of teleoperation inevitably suffers from the problem of heterogeneity. This paper proposed an automatic-switching-based teleoperation framework with asymmetrical mapping and force feedback. Namely, special coefficients are designed to automatically switch the motion states of the remote robot, so that the traditional manual-based switching strategy can be replaced. Based on these coefficients, the hybrid asymmetrical mapping including the position–velocity and position–position modes can be achieved, as well as the force feedback considering the switching between the remote mobile platform and the manipulator, and thereby accomplishing the automatic switching during the teleoperation of the mobile manipulator. The comparative experiments and user study were carried out on the teleoperation platform. The experimental results show that this proposed teleoperation framework can reduce the time needed to complete the tasks and decrease the decision-making pressure of the operator, thus demonstrating the feasibility of the proposed framework. [ABSTRACT FROM AUTHOR]

Surgical robots stand out from medical surgery with the advantages of precise surgery and small incision, but it is difficult for doctors to perform precise control operations on the surgical site only through vision and hearing. Therefore, the application of force feedback in medical operation has become the focus of research in recent years. At present, the problem of force feedback is that the force in the changing collection is not accurate enough. The output of the force feedback structure is unstable and the volume is too large. This paper discusses the feasibility of using magnetorheological fluid (MRF) to realize force feedback, and designs the device structure of force feedback. A solution is proposed for the precise collection of mechanical arm force, and the mean algorithm is used to realize the de-jittered process and improve the collection precision. The performance is improved by more than four times, and the simulation is performed to verify the feasibility. [ABSTRACT FROM AUTHOR]

Virtual Reality (VR) simulators for medical training helps students develop the sensorimotor skills required to perform specific procedures. However, as a training resource, a VR simulator usually lacks the capacity to assess the user's performance automatically and provide feedback. The main objective of this study is to develop a model to automatically assess performance in VR medical simulators, based on the medical instrument trajectories and machine learning. We designed a model to use the data collected in medical VR simulators and defined two different labeling systems: by level of expertise or by a dental instructor assessment. We calculated 98 features related to the participant's performance and combined three different feature selection/fusion algorithms with five classifiers. The SVM algorithm accomplished the best results overall, with an accuracy of 0.77, specificity of 0.60 and sensitivity of 0.94 using the labeling by the dental instructor's assessment. Overall, the results for the performance assessment were promising and the model can be trained for similar VR medical simulators that collects trajectory data through a haptic device. • Two labeling methods: Participant's level of experience and instructor's assessment. • Better results were obtained using datasets with the instructor's assessment label. • Out of five classifiers, the Support Vector Machine achieved the best results. • Four classifiers achieved the best results with the ReliefF feature selection. [ABSTRACT FROM AUTHOR]

Haptic information of biological tissues is important in applications and research in medical fields, including force and tactile feedback. Due to resource limitation, various biological tissues may not be easily accessible, so as to hinder their haptic research and development. Therefore, in this paper, force and tactile feedback of five pig tissue samples are respectively reproduced by using a combination of haptic device and interface. Specifically, the haptic device is used to reproduce the force-displacement relationship, while the haptic interface is used to provide various and controllable touch sensations to human fingers. First, the force-displacement relationships of five pig tissue samples are derived via compression tests. Second, the haptic device with two springs and a customized raceway is designed, modeled, and fabricated. Third, compression tests are performed on the haptic device to verify its reproduction accuracy. Later, the pneumatic haptic interface is designed and fabricated. Last, the haptic device and interface are combined and tested. The proposed haptic device and interface can provide accurate force feedback as well as various and controllable tactile feedback to human fingers. [Display omitted] • The haptic device accurately reproduces the force feedback of biological tissues. • The pneumatic haptic interface provides various and controllable tactile feedback. • Biomechanical properties can be reproduced by springs and customized raceway. [ABSTRACT FROM AUTHOR]

This work studied muscle neuro-mechanics during symmetrical up-going ramp (UGR) and down-going ramp (DGR). Aim: to evaluate during the modulation of muscular action the outcome of force feedback (FF) or neural feedback (NF) on the behavior of the trailing signals - i.e. the EMG envelope (eEMG) for FF or force signal for NF. Subjects: 20. Investigated muscles: dorsal interosseous (FDI) and tibialis anterior (TA). Detected signals: force and EMG. Visual feedback: force (FF), eEMG (NF). Effort triangles: ramps duration 7.5 s, vertex at 50 and 100 % of the maximal voluntary action. Eventually, each subject performed FF50%, FF100%, NF50% and NF100% per each muscle. In each condition the areas beneath the force and eEMG signals were computed to calculate the ratios between the DGR and UGR values during the different tasks (force area DGR / force area UGR; eEMG area DGR / eEMG area UGR). Electro-mechanical coupling efficiency (EMCE) was estimated through the eEMG area / force area ratio for both UGR and DGR in each condition. a) FF. FDI: eEMG area ratio was 0.84 ± 0.15 and 0.73 ± 0.17 for FF50% and FF100%, respectively. TA: eEMG area ratio was 0.88 ± 0.11 and 0.91 ± 0.17 for FF50% and FF100%, respectively. b) NF: FDI: force area ratio was 1.18 ± 0.13 and 1.17 ± 0.13 for NF50% and NF100%, respectively. TA: force area ratio was 1.17 ± 0.21 and 1.07 ± 0.19 for NF50% and NF100%, respectively. c) DGR EMCE was greater than UGR EMCE in all four tasks. The influence of UGR on deployed EMCE in the following force decrement phase underpins the changes of trailing signals area during DGR. This underlines the necessity of a careful evaluation of the features of FF or NF for experimental studies or rehabilitation purposes involving the motor control system. [ABSTRACT FROM AUTHOR]

Abstract A novel control method is proposed for master–slave telerobotic beating-heart surgery to solve the challenges of rapid heart motion and oscillatory haptic feedback. In this paper, the ultrasound imaging-based control algorithms are used to make the slave robot compensate for the heart motion automatically. Issues including slow sampling rate and time delay caused by ultrasound imaging are addressed by a cubic interpolation and an extended Kalman filter (EKF), respectively. Meanwhile, to provide the human operator (surgeon) a feeling of operating on an idle heart, an impedance model is designed for the master robot. The proposed method is validated through experiments. [ABSTRACT FROM AUTHOR]

Abstract This work presents a human-robot closely collaborative solution to cooperatively perform surface treatment tasks such as polishing, grinding, deburring, etc. The method considers two force sensors attached to the manipulator end-effector and tool: one sensor is used to properly accomplish the surface treatment task, while the second one is used by the operator to guide the robot tool. The proposed scheme is based on task priority and adaptive non-conventional sliding mode control. The applicability of the proposed approach is substantiated by experimental results using a redundant 7R manipulator: the Sawyer cobot. Highlights • We develop a human-robot collaboration for cooperative surface treatment tasks. • We use a force sensor to properly accomplish the surface treatment task. • Another force sensor is used to guide the tool tracking the operator's forces. • The controller is based on an adaptive non-conventional sliding mode control. • The effectiveness of the method is shown through simulation and real experimentation. [ABSTRACT FROM AUTHOR]

In this paper, a hand exoskeleton system for virtual reality is proposed. As a virtual reality interface for the hand, a wearable system should be able to measure the finger joint angles and apply force feedback to the fingers at the same time with a simple and light structure. In the proposed system, two different cable mechanisms are applied to achieve such requirements; three finger joint angles in the direction of the flexion/extension (F/E) motion are measured by a tendon-inspired cable mechanism and another cable is used for force feedback to the finger for one degree of freedom (DOF) actuation per finger. As two different types of cables are used, the system is termed a dual-cable hand exoskeleton system. Using the measured finger joint angles and motor current, the cable-driven actuation system applies the desired force to the fingers. That is, when the desired force is zero, the motor position is controlled to follow the finger posture while maintaining the appropriate cable slack; when the desired force needs to be applied, the motor current is controlled to generate the desired force. To achieve a smooth transition between the two control strategies, the control inputs were linearly integrated; and the desired motor position was generated to prevent a sudden motor rotation. A prototype of the proposed system was manufactured with a weight of 320g, a volume of 13 × 23 × 8 cm 3 , maximum force up to 5  N . The proposed control algorithms were verified by experiments with virtual reality applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The state-of-the-art of shape memory alloy haptic wearable devices is reviewed. • Working performances and features of shape memory alloy are introduced. • Diverse shape memory alloy mechanisms and haptic feedback types are correlated. • A design process for shape memory alloy haptic wearables is proposed based on material-centred approach. Devices delivering sophisticated and natural haptic feedback often encompass numerous mechanical elements, leading to increased sizes and wearability challenges. Shape memory alloys (SMAs) are lightweight, compact, and have high power-to-weight ratios, and thus can easily be embedded without affecting the overall device shapes. Here, a review of SMA-based haptic wearables is provided. The article starts with an introduction of SMAs, while incorporating analyses of relevant devices documented in the literature. Haptic and SMA materials fields are correlated, with haptic perception insights aiding SMA actuator design, and distinct SMA mechanisms offering diverse haptic feedback types. A design process for SMA haptic wearables is proposed based on material-centered approach. We show SMAs hold potential for haptic devices aiding visually impaired people and promise in immersive technology and remote interpersonal haptic communication. [ABSTRACT FROM AUTHOR]

In the teleoperation, the force feedback is indispensable, which can enhance the sense of presence of the operator and help the operator accomplish tasks comfortably. The time delay is one of the main challenges that influence the stability of the teleoperation systems, which leads to the discontinuous operation. Thus building a local virtual model in the master side is an effective way to solve this problem. In this paper, a new method is presented to reconstruct the virtual model of the remote object. The virtual model can estimate the real-time force feedback to the operator and eliminate the effects of the time delay. Then the tele-robotic system based on augmented reality technology is set up in our laboratory. In the tele-robotic system, the dynamic parameters including damping and stiffness of the virtual model are constantly updated by utilizing the positions and forces information from sensors of the remote robot site. Finally, the effectiveness of the proposed method and the correctness of the visual model parameters are verified by two experiments. [ABSTRACT FROM AUTHOR]

Remote robots in bilateral teleoperation systems are utilized to accomplish various missions in different locations, which are generally far away from local robots collocated with a human operator. In order to enhance flexibility of teleoperators with extensive applicability, this paper proposed a novel control framework, where the remote controller is non-collocated with the robot in the environment. In contrast to traditional teleoperation systems, the remote robot only needs to send out sensory information and receive control commands from the local side. Stability and transparency of the proposed teleoperators are studied for PD-like controller with fixed time delays, and P-like controller with time-varying delays. If the control gains are contingent to upper bounds of time delays, then the system is stable with guaranteed position tracking and force reflection. Numerical simulations and experiments were conducted to demonstrate the effectiveness of the proposed control algorithms in bilateral teleoperation. [ABSTRACT FROM AUTHOR]

Surgical manipulators are widely used for laparoscopic surgery. They have mainly been chosen for use in supporting human operations and in robot systems like the da Vinci surgical system. These manipulator systems are suitable for careful work, but they have a few problems. One is that the manipulators are not equipped with haptic sensing functions. Therefore, the operator must know advanced techniques for visually detecting the physical contact state during surgical operation. Such haptic sensing functions thus need to be incorporated into surgical manipulators. We have developed hydraulic-driven forceps with a micro bearing and a bellows tube that can convey haptic sense to the operator. For accurate surgical operation, the operator of the surgical manipulator must be able to feel the characteristics of the blood vessel and the organ. For example, it is necessary to feel the pulsation of the blood. In addition, the operator must be able to notice any potential rupture of a blood vessel to prevent a medical accident. We tested our system to determine if it could detect characteristic differences and changes of the blood vessel. This report describes the results and discusses the effectiveness of our system. [ABSTRACT FROM AUTHOR]

An “office-based surgical device” is a kind of device which aims to shift the conventional surgical procedures from the operating room to the confines of the doctor’s/surgeon’s office as well as to assist the surgeons to carry out the surgeries on the patients automatically or semi-automatically. In this paper, an office-based surgical device suitable for patients with Otitis Media with Effusion (OME) is introduced. Due to the office-based design, it is not possible to subject the patient to general anesthesia, i.e., the patient is awake during the surgical treatment with the device. To ensure a high success rate and safety, it is very important that the relative motion and the contact force between the tool set of the device and the tympanic membrane (TM) can be stabilized. To this end, a control scheme using force and vision feedback is proposed. The force feedback controller is a PID-based (proportional-integral-derivative) controller, which is designed for force tracking. The vision feedback controller is a vision-based motion compensator, which is designed to measure and compensate the head motion since it is equivalent to TM motion. Furthermore, the control scheme is implemented and tested in a mock-up system. The experimental results show that the proposed composite controller can achieve much better performance in force tracking than a pure force feedback controller. The performance can at least improve by 20% after augmenting the motion compensator, which helps the system to stabilize the relative motion indirectly and maintain the contact force precisely. [ABSTRACT FROM AUTHOR]

Recently, surgical manipulators have been widely used to support human operations, such as surgical operations. These manipulator systems are suitable for careful work, but they have a few problems. One problem is that the manipulators are not equipped with haptic sensing functions. When a manipulator does not employ haptic sensing functions, an operator can only conduct an operation using visual feedback. Therefore, to substitute for visual detection, it is necessary for the operator to use advanced techniques to determine physical contact during an operation. We have developed a new mechanism to solve this problem. A hydraulically driven joint is constructed in a spherical bearing and bellows tubes that enables a haptic sense display for the operator. This system can measure the small forces acting on the tips of the manipulator using Pascal’s principle. A model of the system is derived from the relationship between the internal pressure of the bellows tube and the refraction angles of the joint. In this study, we quantitatively investigated the relationship between the internal pressure of the bellows tubes and the refraction angles of the joint. To estimate the refraction angle, we measured the quantity of water that was provided from syringes. It was confirmed that the developed system allowed for an estimation of both the strength and direction of the external force applied to the manipulator by measuring the bellows tubes’ internal pressure. This report describes the prototype joint. [ABSTRACT FROM AUTHOR]

In this paper, a novel control scheme is presented to achieve simultaneous position and force coordination in nonlinear teleoperation systems. Providing force feedback would facilitate the task for the operator and increase the performance. The four channel architecture is employed for this target as a high transparent structure. However, the stability issue has been a challenging problem, even in the sense of linear teleoperators. By employing a novel nonlinear damping, the stability of the closed loop system has been preserved even when the communication channel is subjected to time varying delay. In addition, no passivity condition is required for both the operator and the environment, a restrictive condition which is not always held in practice. We also proved through Lyapunov–Krasovskii functions that position and force tracking error will asymptotically converge to zero. The controllers do not require any knowledge of the robot dynamics except the gravity terms. In order to verify the effectiveness of the proposed controller, a simulation result is presented, illustrating both position and force coordination in such nonlinear systems. [ABSTRACT FROM AUTHOR]

This paper presents a spherical joint actuator using an electrorheological (ER) fluid to make a new haptic master which can be applicable to a robot-assisted cutting surgery. The proposed haptic master consists of two actuators for different motions; ER spherical joint device for 3-DOF rotational motion and ER linear device for 1-DOF translational motion. An appropriate size of the haptic master is designed based on the governing equations of the dynamic model and manufactured. The haptic master is then connected to a slave robot for the cutting surgery of a tissue. In the surgical process, the forces required to cut the tissue (a pork in this work) are obtained using a force sensor via experimets and used as the desired forces to be tracked by a slave robot controlled by a proportional-integrative-derivative (PID) controller. The desired repulsive forces are then embodied through the haptic master so that the operator can feel the forces occurred in cutting process (actual forces). In order to validate the effectiveness of the proposed haptic master, the tracking control performances between the desired force and actual force are evaluated in time domain. [ABSTRACT FROM AUTHOR]

The steering system for working machines attachment is a mediator between operator and the environment, thus it is one of the main factors which influence the efficiency and safety of the operator's work. The subject of this article is the test stand which enables one to test various steering systems for the hydraulic driven working attachment. The test stand is designed and already build by authors. The close representation of the real working attachment manipulation conditions as well as the ability to connect various steering systems to it were the main design criterions. The first one was obtained by imitation of the maximal angular range and the maximal angular speed of the boom and the stick from the real working machine. The micro-controller ATmega 32 was used as a supervisory system of the mechanical arm. This solution grants the test stand the ability to attend various steering systems without major changes of its construction. [ABSTRACT FROM AUTHOR]

Molecular docking systems model and simulate in silico the interactions of intermolecular binding. Haptics-assisted docking enables the user to interact with the simulation via their sense of touch but a stringent time constraint on the computation of forces is imposed due to the sensitivity of the human haptic system. To simulate high fidelity smooth and stable feedback the haptic feedback loop should run at rates of 500 Hz to 1 kHz. We present an adaptive force calculation approach that can be executed in parallel on a wide range of Graphics Processing Units (GPUs) for interactive haptics-assisted docking with wider applicability to molecular simulations. Prior to the interactive session either a regular grid or an octree is selected according to the available GPU memory to determine the set of interatomic interactions within a cutoff distance. The total force is then calculated from this set. The approach can achieve force updates in less than 2 ms for molecular structures comprising hundreds of thousands of atoms each, with performance improvements of up to 90 times the speed of current CPU-based force calculation approaches used in interactive docking. Furthermore, it overcomes several computational limitations of previous approaches such as pre-computed force grids, and could potentially be used to model receptor flexibility at haptic refresh rates. [ABSTRACT FROM AUTHOR]

This paper deals with robust force control at the microscale for safe manipulation of deformable soft materials. Since mechanical properties of micrometer sized objects are highly uncertain, instability often occurs during a gripping task. This leads to object damage or destruction due to excessive gripping force. In this paper we propose the design of a robust dynamic output feedback controller that is able to insure desired performances for a set of 65 soft and resilient microspheres whose diameter ranges from 40 μm to 80 μm and stiffness varies from 2.8 N/m to 15.7 N/m. The degrees of freedom of the controller are managed by the use of a set of elementary observers. Robustness with respect to parametric uncertainties is satisfied thanks to an iterative procedure alternating between multimodel closed loop eigenstructure assignment and worst case analysis. The developed controller is of low order and can be implemented in real time. Robust gripping force control is for the first time demonstrated experimentally when dealing with the manipulation of a large number of variable deformable soft materials at the microscale. Both simulations and experimental results validate the interest of such control design approach. [ABSTRACT FROM AUTHOR]

For surgeons performing open procedures, the sense of touch is a valuable tool to directly access buried structures and organs, to identify their margins, detect tumors, and prevent undesired cuts. Minimally invasive surgical procedures provide great benefits for patients; however, they hinder the surgeon's ability to directly manipulate the tissue. In our previous work, we developed a Wireless Palpation Probe (WPP) to restore tissue palpation in Minimally Invasive Surgery (MIS) by creating a real-time stiffness distribution map of the target tissue. The WPP takes advantage of a field-based magnetic localization algorithm to measure its position, orientation, and tissue indentation depth, in addition to a barometric sensor measuring indentation tissue pressure. However, deformations of both the tissue and the silicone material used to cover the pressure sensors introduce detrimental nonlinearities in sensor measurements. In this work, we calibrated and characterized different diameter WPP heads with a new design allowing exchangeability and disposability of the probe head. Benchtop trials showed that this method can effectively reduce error in sensor pressure measurements up to 5% with respect to the reference sensor. Furthermore, we studied the effect of the head diameter on the device's spatial resolution in detecting tumor simulators embedded into silicone phantoms. Overall, the results showed a tumor detection rate over 90%, independent of the head diameter, when an indentation depth of 5 mm is applied on the tissue simulator. [ABSTRACT FROM AUTHOR]

Sensorimotor performance is known to deteriorate during spaceflight. Prior research for instance documented that targeted arm motions are performed slower and less precise in microgravity conditions. This article describes an experiment on aiming performance during different stages of a space mission. Moreover, the influence of different haptic settings of the human-machine interface (HMI) was explored. Two separate studies are presented in which the same aiming tasks were performed with a force feedback joystick: 1) A terrestrial study (N = 20) to explore time and haptic setting effects and 2) a space experiment (N = 3) with a pre-mission session, three mission sessions on board the ISS (2, 4, and 6 weeks in space), and a post-mission session. Results showed that sensorimotor performance was mainly affected in the initial phase of exposure to microgravity and this effect was moderated by astronauts' sensorimotor skills. Providing low stiffness at the HMI, however, proved to be an effective measure to maintain aiming precision in microgravity. [ABSTRACT FROM AUTHOR]

Restoring tissue palpation in Minimally Invasive Surgery (MIS) procedures has been a relevant research topic in the last decade. Among the developed devices the Wireless Palpation Probe (WPP) embeds a barometric pressure sensor to create a stiffness distribution map of underlying tissues. In this work we characterized nine different interchangeable WPP heads fabricated with the combination of three different thickness/materials. Step responses and stress strain were evaluated to assess the best material and thickness combination for the next WPP heads fabrication. [ABSTRACT FROM AUTHOR]

The conceptual design of several gripping tools and their mechanical interfaces is being carried out for the ITER ECH UPP within the WP10-GOTRH programme. EFDA finances the GOT RH (Goal Oriented Training Programme for Remote Handling). The purpose of this paper is to introduce new concepts of gripping tools for the plug extraction/insertion in the upper port of ITER. All these gripping tools are designed according to IO input data and geometrical constraints. The gripping tools have to be able to extract/insert the plug in the scenario of maximum misalignment between the plug and the tractor. The paper also defines the functional requirements the gripping tools need to comply with. The requirements and input data are verified and validated through 3D simulation with Catia mock-ups of the gripping tools. The strengths and weaknesses of each gripping tool model are compared. [ABSTRACT FROM AUTHOR]

A simple device based on friction coefficient control was designed as a solution to the lack of compactness and simplicity encountered in the number of force feedback interfaces. The structure comprises a 64 x 38 x 3 mm copper-beryllium plate on which well-adjusted polarized piezoceramics are glued. The plate stands on four legs, each of which has a spherical end. By controlling the drive voltage, friction force may be varied as required by a user who moves the device on a flat surface, as he or she would do with a normal mouse. This adds the possibility of rendering simulated forces from objects manipulated on a PC screen. Friction forces obtained using Hertz contact theory compare well with the ones measured on an experimental setup, which demonstrate the validity of the approach with regard to force feedback application. [ABSTRACT FROM AUTHOR]

Abstract: It is believed that force feedback can modulate lower extremity extensor activity during gait. The purpose of this research was to determine the role of limb loading on knee extensor excitability during the late stance/early swing phase of gait in persons post-stroke. Ten subjects with chronic hemiparesis post-stroke participated in (1) seated isolated quadriceps reflex testing with ankle loads of 0–0.4Nm/kg and (2) gait analysis on a treadmill with 0%, 20% or 40% body weight support. Muscle reflex responses were recorded from vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) during seated testing. Knee kinematics and quadriceps activity during late stance/early swing phase of gait were compared across loading conditions. Although isolated loading of the ankle plantarflexors at 0.2Nm/kg reduced VM prolonged response (p =0.04), loading did not alter any other measure of quadriceps excitability (all p >0.08). During gait, the use of BWS did not influence knee kinematics (p =0.18) or muscle activity (all p >0.17) during late stance/early swing phase. This information suggests that load sensed at the ankle has minimal effect on the ipsilateral quadriceps of individuals post-stroke during late stance. It appears that adjusting limb loading during rehabilitation may not be an effective tool to address stiff-knee gait following stroke. [Copyright &y& Elsevier]

Abstract: In this paper the force feedback computation is investigated for improving the quality of the haptic feedback in virtual reality applications. The chosen structure for the force feedback device is string based and characterized by 3 degrees of freedom (force-feedback only) or 6 degrees of freedom (force and torque feedback). This haptic device is used together with a three-sided stereoscopic immersive visualization system to convincingly create sensations associated with forces and also with the shape and texture of the displayed objects. Feelings in general are not easy to simulate by computer technology and haptic information (force and torque feedback) can be distorted by incorrect distribution of the tension forces in the strings or delays in the computation process, because it must be updated at very high rate (approximately 1000Hz). In this paper a new method is suggested, in which the number of computation step is fixed and the amount of calculation is low and always limited. [Copyright &y& Elsevier]

Abstract: To train competitive sailing in a virtual setting, motion of the boat as well as haptic feedback of the sail lines is essential. When discussing virtual environments (VEs) the concept of presence is often used. In this study we develop a sailing simulator motion system to research what factors contribute to the participants’ sensation of presence when sailing in a VE. The developed simulator includes the development of a mainsheet force feedback system and a novel motion platform, connected to a high-quality graphics sailing simulation. In future research, the developed system will be used to study which sail training type can be performed in simulated environments, and if the system can be used as a valid testbed for perception-action experiments. [Copyright &y& Elsevier]

Abstract: For the application to the resection of brain tumor, force detecting micro gripper and force feedback system has been developed. Grasping force and pulling force at the gripper are transmitted to the master operating system where the surgeon feel the gr ipping force as force resistance and pulling force as friction on the finger surface. The feeling at the master operator has been investigated through the gripping test on soft materials in various hardness applying force reflection bilateral control program. Topics: OS2: Medical devices and medical tools. [Copyright &y& Elsevier]

Abstract: In many haptics applications, fast and stable force response with high strength is highly desired. While the existing active and passive actuators cannot fully satisfy these requirements alone, their cooperation could provide better results. This study aimed at the development of a hybrid actuator by combining a DC servomotor and a magnetorheological (MR) brake. Serpentine flux path architecture was used to design a compact MR-brake. By embedding a Hall-effect sensor in the brake, the hysteresis challenges and residual off-state torque were eliminated. In this approach, the sensor measures the flux across the MR-fluid while a PI controller directly manipulates the magnetic induction level. To the best of our knowledge, this is the first such design incorporated into an MR-brake. The control scheme determines the motor and brake inputs separately based on their capabilities. During operation, the brake is activated to provide an average force profile while the motor superimposes the finer details on this profile. The hybrid actuator can provide a stiff wall collision effect when the needle touches a bone. It can also enable fast tracking during sudden force variations as they happen during virtual needle insertion and removal into virtual tissue layers. [Copyright &y& Elsevier]

Abstract: In this paper, an innovative sensor for the control of a tendon-driven mechatronic system is presented. The proposed sensor measures the tendon tension using optoelectronic components properly selected and mounted on a suitably designed compliant frame. This solution presents several advantages mainly in terms of simplicity and compactness with respect to force sensors based on strain-gauge or Bragg-grating. By exploiting the properties of optoelectronic components with a narrow angle of view and by means of a very simple conditioning electronics, the very small deformation of the compliant frame caused by the tendon force can be measured. Moreover, the compliant frame has been designed to allow the sensor to be mounted in any position along the tendon. The sensor working principle, an optimal design procedure and the results of an experimental testbench where two of the proposed sensors are used for the feedback control of a tendon-driven mechatronic system are reported in the paper. The experimental verification of a contact force estimation algorithm useful for grasping and manipulation purposes in which the data collected by the optoelectronic tendon force sensors are exploited is also reported in the paper. [Copyright &y& Elsevier]

Abstract: This survey presents the application of force feedback in aviation. In modern fly-by-wire control system, actuator rate limit is the primary source of PIO II (Pilot Induced Oscillation II). The combination of smart-cue and smart-gain method can alleviate PIO II effectively, and consequently enhance the flight safety. The recent research of applying force feedback in aviation demonstrates that it is worthy of theoretical exploration and extensive utilization. [Copyright &y& Elsevier]

Abstract: In this contribution, a systematic method for the design of open- and closed-loop controllers for vibratory MEMS gyroscopes based on so-called envelope models will be presented. The methodology will be exemplarily carried out for a gyroscope with electrostatic actuation and read-out elements. The specifically designed capacitive actuators of the gyroscope are capable of compensating the system’s inherent mechanical unbalance (quadrature compensation) as well as the system’s response to an external angular rate (force feedback). The utilized envelope model solely captures the relevant system dynamics of the gyroscope while at the same time describing the actuation and read-out mechanisms simplified to a suitable level of detail thus providing the basis for an efficient and systematic control design. In order to demonstrate the proposed methodology, an optimized start-up strategy for the control of the primary oscillation is designed. Furthermore, the approach is utilized for the deviation of a basic quadrature controller for the secondary oscillation. In order to account for the typically weakly damped open-loop dynamics of the gyroscope and the transient coupling between the quadrature and the angular rate signal a more sophisticated combined concept of closed-loop quadrature and force feedback control is introduced. Both simulation and measurement results obtained for a prototype gyroscope validate the mathematical models and prove the feasibility of the proposed concepts. [Copyright &y& Elsevier]

Abstract: Humans control their movements using adaptive proprioceptive feedback from muscle afferents. The interaction between proprioceptive reflexes and biomechanical properties of the limb is essential in understanding the etiology of movement disorders. A non-linear neuromuscular model of the wrist incorporating muscle dynamics and neural control was developed to test hypotheses on fixed dystonia. Dystonia entails sustained muscle contractions resulting in abnormal postures. Lack of inhibition is often hypothesized to result in hyperreflexia (exaggerated reflexes), which may cause fixed dystonia. In this study the model-simulated behavior in case of several abnormal reflex settings was compared to the clinical features of dystonia: abnormal posture, sustained muscle contraction, increased stiffness, diminished voluntary control and activity-aggravation. The simulation results were rated to criteria based on characteristic features of dystonia. Three abnormal reflex scenarios were tested: (1) increased reflex sensitivity—increased sensitivity of both the agonistic and antagonistic reflex pathways; (2) imbalanced reflex offset—a static offset to the reflex pathways on the agonistic side only; and (3) imbalanced reflex sensitivity—increased sensitivity of only the agonistic reflex pathways. Increased reflex sensitivity did not fully account for the features of dystonia, despite distinct motor dysfunction, since no abnormal postures occurred. Although imbalanced reflex offset did result in an abnormal posture, it could not satisfy other criteria. Nevertheless, imbalanced reflex sensitivity with unstable force feedback in one of the antagonists closely resembled all features of dystonia. The developed neuromuscular model is an effective tool to test hypotheses on the underlying pathophysiology of movement disorders. [Copyright &y& Elsevier]

Abstract: Distraction osteogenesis can result in high forces developing in the limb. To determine and control the distraction forces (DF), a motorized distractor driven by feedback from DF was developed and used to lengthen the tibiae of 6 sheep undergoing distraction osteogenesis. The forces were measured continually, and, in 4 of the sheep, a force threshold was set, above which an increase in rate was initiated. The rate kept increasing to a set limit if forces remained above the threshold; otherwise, the rate was decreased. Radiographs were acquired biweekly, and muscle samples were analyzed from both the operated and contralateral limbs upon termination of the experiment. Results demonstrated a drop in DF associated with increased lengthening rate, attributed to separation of the callus as indicated by radiography. Histological evidence of muscle damage generally correlated with higher DF levels. There was a significant decrease in muscle fiber diameter in lengthened relative to contralateral limbs. Collectively, the results demonstrated the use of a force-driven distraction system and support the need for considering force data in regulating distraction rates to achieve optimal clinical outcomes. [Copyright &y& Elsevier]

Abstract: In this research, a new 2-DOF hybrid actuator concept is explored as a powerful and compact alternative to conventional haptic actuators. The actuator combines a spherical MR-brake and three air muscles and is integrated into a joystick that can apply forces in two degrees-of-freedom. The air muscles are used to create high active forces in a compact volume and the brake compensates for the “spongy” feeling associated with air muscles. To decrease the overall size of the system an inertial measurement unit has been implemented as a position measurement solution. As high as 16N of total force output could be achieved at the tip of the joystick. Also, up to 16 times improvement in the stable virtual wall stiffness was obtained when the MR-brake was used to compensate for force errors. Experiments with an impedance-based haptic controller with force-feedback gave satisfactory wall following performance. This device can be employed in applications including computer games, military or medical training applications, rehabilitation and in teleoperation of equipment where high force feedback in 2-DOF in a compact work volume may be desirable while interacting with rigid or elastic virtual objects. [Copyright &y& Elsevier]

Abstract: This paper presents an energy-bounding approach to a rate-mode bilateral control of remote vehicles in order to guarantee the robust system stability in variable time-delayed and data-dropped telecommunication environments. The velocity error between desired and actual remote vehicle velocities is reflected in term of force in order to maintain the desired velocity by the operator during the normal driving in obstacle-free environments and in order to detect the collision when colliding with a high impedance wall. A rate-mode energy-bounding algorithm is devised for these teleoperation scenarios in order to feel velocity differences sensitively while guaranteeing robust interaction stability. Effectiveness of the proposed approach is shown by some typical experimental results in the simulated variable time-delayed and data-dropped environments. [Copyright &y& Elsevier]

Abstract: This paper presents a novel tool for the analysis of new molecular structures which enables a wide variety of manipulations. It is composed of a molecular simulator and a haptic device. The simulation software deals with systems of hundreds or thousands of degrees of freedom and computes the reconfiguration of the molecules in a few tenths of a second. For the ease of manipulation and to help the operator understand nanoscale phenomena, a haptic device is connected to the simulator. To handle a wide variety of applications, both position and force control are implemented. To our knowledge, this is the first time the applications of force control are detailed for molecular simulation. These two control modes are compared in terms of adequacy with molecular dynamics, transparency and stability sensitivity with respect to environmental conditions. Based on their specificity the operations they can realize are detailed. Experiments highlight the usability of our tool for the different steps of the analysis of molecular structures. It includes the global reconfiguration of a molecular system, the measurement of molecular properties and the comprehension of nanoscale interactions. Compared to most existing systems, the one developed in this paper offers a wide range of possible experiments. The detailed analysis of the properties of the control modes can be easily used to implement haptic feedback on other molecular simulators. [Copyright &y& Elsevier]

Abstract: This paper presents a new sensor arrangement and feedback controller for hysteresis, creep and vibration in piezoelectric actuators. A piezoelectric force sensor is combined with a resistive strain gage to provide both extremely low noise and high stability. The use of a force sensor also results in a system transfer function that exhibits zero-pole ordering. Such systems allow a simple integral controller to provide excellent tracking and damping performance with guaranteed stability. The proposed technique is demonstrated on a nanopositioning platform with a range of 10 m and a resonance frequency of 2.4kHz. In closed-loop, the controller damps the resonance by 33dB and provides a tracking bandwidth of 1.8kHz. Excellent tracking of a 130Hz triangular reference and reduction of hysteresis to 0.46% at 10Hz is also demonstrated. The closed-loop positioning noise, predicted from the sensor noise density, was approximately 0.67nm peak-to-peak, or 0.0067% of the 10 m range. [Copyright &y& Elsevier]

Abstract: This research aimed to address two main goals in the development of a rotary magnetorheological fluid (MRF) brake: (1) design of a compact and powerful brake and (2) low friction sealing technique to reduce the off-state braking torque and prevent the fluid from leaking. Using magnetically conductive and non-conductive rings a serpentine flux path was developed to weave the magnetic flux through the MRF. Experimental results showed that, when compared to a commercial MRF brake, our 33% smaller prototype MRF brake could generate 2.7 times more torque (10.9Nm). A ferro-fluidic sealing technique was developed that resulted in sealing in the fluid and decreased the off-state friction. Further reduction in the off-state torque was obtained by applying a reverse current pulse to collapse a residual magnetic field in the brake. A 1-DOF haptic interface employing the brake enabled crisp virtual wall collision and Coulomb friction simulations. [Copyright &y& Elsevier]

Abstract: Due to lack of position and velocity feedbacks in MM3A nanomanipulator, a fused vision/force feedback robust controller has been recently designed by the authors. This second paper in the series presents the optimal utilization of the visual servoing and force sensor feedbacks for use in the nanomanipulation tasks discussed in the first paper (Part A). More specifically, the visual servoing and force feedback structures are investigated through extensive simulations in order to reveal issues in practical implementation. For this, a set of numerical simulations is performed to demonstrate the effectiveness of utilizing just vision feedback as well as force feedback only, at both macro and microscale. It is shown that although each feedback module could provide reasonably accurate results at either macro or microscale, precise positioning of such nanomanipulator requires employment of both modules with a proper (optimal) switching strategy. This paper extends our previously introduced robust controller for nanomanipulator positioning and offers a novel switching framework to be used between vision feedback and force feedback modules. Utilizing a soft switching function, the problem of jump in the actuator force during fused vision/force control of the nanomanipulation can be overcome. Following the development of the soft switching approach, numerical simulations are used to verify the positioning performance and effectiveness of each switching strategy. [Copyright &y& Elsevier]

Abstract: A novel triaxial force sensing device developed by the authors with a MEMS sensor as core component is mounted on a subnanometric resolution nanomanipulator having three degrees of freedom (DOF). This sensorized device allows measuring forces on the nanomanipulator tip in the range of 0–3N for normal and ±50mN for tangential forces with a resolution of 11bits. Together with a haptic input device, a setup was created allowing palpation and force feeling. The mathematical model used to drive the master haptic interface force feedback capabilities is based on online force and stiffness measurement. The performance of the novel setup is demonstrated with a cell palpation experiment. [Copyright &y& Elsevier]

A novel 6 degrees of freedom (DOFs) wearable exoskeleton arm, ZJUESA, based on man-machine system is presented. It can be used in robot bilateral teleoperation as master arm with force-feedback. With introducing the revolute-prismatic-spherical (RPS) parallel mechanism and planetary gear mechanism, it is designed based on the anatomy of human upper-limb. With the sensors on this external mechanical structure, the human operator motion is detected and converted to the slave robot control command. Additionally the pneumatic system on it generates a force feedback by using hybrid fuzzy control. As a result, the human operator may have a feeling of doing the work directly. [ABSTRACT FROM AUTHOR]

Abstract: We describe the application of haptic technology to enhance the information available in chemical systems, specifically related to computational drug design. These methods are designed to build upon the visual information presented by molecular viewers and add the sensation of touch, or force feedback. The addition of sensory input can aid in the analysis of molecular structures and the understanding of intermolecular interactions by delivering chemically relevant forces to the end user. [Copyright &y& Elsevier]

Abstract: Mechanization is necessary for safer and more efficient underwater construction work in port areas. Teleoperated underwater construction machines are under developing. The problem is that conventional TV camera system is useless in water because of turbidity. Haptic information is introduced as the aid to control construction machines substituting for visual information. Components of control technologies are visualization of haptic image, force feedback, and similar figure controller. Leveling experiment of gravel mound was carried out successfully on land with an experimental land model of underwater backhoe. [Copyright &y& Elsevier]

Abstract: In this paper we report on the analysis and simulations carried out in the robotics laboratory of the University of Verona for the development of a simulator for endoscopic procedures in the liver. In particular we are concerned with the development of a model of the liver able to reproduce the local deformations and forces that the surgeon experiences during a real operation. This article is divided into two main parts. The first gives a short summary of the existing bibliography in order to highlight the mechanical behaviour of the tissue. The second part describes the work we have done to create the simulator. We particularly explain the methodology used to simulate the forces experienced by the surgeon during surgery. The results of the simulations carried out are reported to evaluate the efficiency of the suggested procedure. [Copyright &y& Elsevier]

Abstract: The introduction of telemanipulator systems into cardiac surgery enables the heart surgeon to perform sophisticated mini-invasive and endoscopic procedures with high precision under stereoscopic view. At present, the commercially available robotic surgical systems do not dispose of force feedback for the operating surgeon. The lack of haptic (force or tactile) feedback causes damage of tissue and bending or breaking of suture material. For further improvement of telemanipulated systems, we implemented haptic into a realistic experimental platform to evaluate force-feedback for robotic heart surgery. [Copyright &y& Elsevier]

Abstract: Virtual reality training systems can support the education of surgeons. Using haptic displays as input devices for hands-on training, learning effects are improved. One reason for the poor application field of force feedback devices is the limited variety of available commercial products. Thus, we developed a new interface, which is more flexible to use with force reflecting hardware. The resulting control electronics has a modular design, it is easily configurable and it is based on USB and network technology, respectively. We built new types of haptic devices that apply to endoscopic neurosurgery, ENT surgery and laparoscopy simulation. Special virtual reality simulation models were designed for the application of the new hardware. In a comparative study of the new system we proved the usability and the learning effect to be of an advantage. [Copyright &y& Elsevier]

Abstract: Functional endoscopic sinus surgery is a minimally invasive technique that is carried out in high numbers. It combines an excellent outcome with minimal patient discomfort. Due to the anatomy, the procedure implies a high risk for the patient concerning the orbita and skull base. This problem and the level of costs in surgical training prompted us to develop a virtual training system coupled with a force feedback device for endoscopic sinus surgery. A pilot series with 10 inexperienced surgeons showed that the simulation is close to reality in parameters like aspect, anatomy, property of tissue and perceived resistance. The system opens up new perspectives in surgical training. [Copyright &y& Elsevier]