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In the field of rehabilitation engineering, wearable robots for upper limbs tend to help powerless arms of patients smoothly complete daily activities. Compared with traditional rigid exoskeleton, soft exosuit takes the advantage of high movement flexibility and relatively compact structure so that it could be a more adaptive and compliant alternative for the elder and the disabled. In this study, a novel dual-arm exosuit is proposed to provide active assistance for multiple joints through bidirectional cable-driven modules. Several Bowden cables achieve power transmission from actuators mounted on the back to shoulders and elbows. The actuator is designed with reference to the principle of differential mechanism, in order to automatically preload both cables wrapped around it, generate assistive torque in two opposite rotation directions of a joint, and keep the human-robot interaction as safe as possible. This study adopts the constant torque control to assist in the pre-tightening process, and develop a model-based control strategy for bidirectional joint motion enhancement according to mathematical models of the human-robot system. The experimental results demonstrate that the prototype can impose pretension on each cable, and offer enough support on the joint according to the wearers' demands. [ABSTRACT FROM AUTHOR]

Surgical robots have been widely researched due to their features of accurate positioning, no jitter, high precision, and low error rate under certain tasks. However, it is generally relatively slow to the feedback generated by force, deformation, or sudden and arbitrary impact during operation. Besides, the feedback is always provided through a vision that cannot meet the actual operation requirements for doctors. The customized design and integration of force perception functions on different robots have become one of the research hotspots of surgical robotics-worldwide recently. A force perception sensor for surgical robots based on Fiber Bragg grating (FBG) is proposed in this paper. It can be used to measure three-dimensional force. The experimental parameters are utilized to calibrate the model through the least square method. A four DoFs experimental platform is constructed. The system errors of the sensor involved are evaluated. The effectiveness of the proposed algorithm can be proved by the experimental results

With the increasing demand for efficiency and intelligence in grinding operations, the research of the automatic robotic processing method for complex surface workpieces becomes necessary. This paper proposes a new approach for robotic grinding on the free-form surface. Particularly, the authors design a novel force-controlled belt grinding tool, on which a contact model of grinding process is further developed. In order to improve the efficiency of grinding, a rapid robot trajectory planning method is proposed based on the workpiece's computer-aided design model, and the process parameters are identified from simple experiments. Furthermore, a piecewise parameterized force control method based on impendence control for the tool is presented, and the purpose of this method is to compensate for the error caused by the rapid planning method and low consistency workblanks. Finally, the grinding experiments of the plate workpiece and complex shape workpiece are performed. The experiment results demonstrate that the proposed method is effective. [ABSTRACT FROM AUTHOR]