tailieunhanh - Báo cáo khoa hoc:" Design of a series visco-elastic actuator for multi-purpose rehabilitation haptic device"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Design of a series visco-elastic actuator for multi-purpose rehabilitation haptic device | JOURNAL OF NEUROENGINEERING AND REHABILITATION Design of a series visco-elastic actuator for multi-purpose rehabilitation haptic device Oblak and Matjacic Oblak and Matjacic Journal of NeuroEngineering and Rehabilitation 2011 8 3 http content 8 1 3 20 January 2011 BioMed Central Oblak and Matjacic Journal of NeuroEngineering and Rehabilitation 2011 8 3 http content 8 1 3 Hill JOURNAL OF NEUROENGINEERING NCR AND REHABILITATION METHODOLOGY Open Access Design of a series visco-elastic actuator for multi-purpose rehabilitation haptic device Jakob Oblak Zlatko Matjacic Abstract Background Variable structure parallel mechanisms actuated with low-cost motors with serially added elasticity series elastic actuator - SEA has considerable potential in rehabilitation robotics. However reflected masses of a SEA and variable structure parallel mechanism linked with a compliant actuator result in a potentially unstable coupled mechanical oscillator which has not been addressed in previous studies. Methods The aim of this paper was to investigate through simulation experimentation and theoretical analysis the necessary conditions that guarantee stability and passivity of a haptic device based on a variable structure parallel mechanism driven by SEA actuators when in contact with a human. We have analyzed an equivalent mechanical system where a dissipative element a mechanical damper was placed in parallel to a spring in SEA. Results The theoretical analysis yielded necessary conditions relating the damping coefficient spring stiffness both reflected masses controller s gain and desired virtual impedance that needs to be fulfilled in order to obtain stable and passive behavior of the device when in contact with a human. The validity of the derived passivity conditions were confirmed in simulations and experimentally. Conclusions These results show that by properly designing variable structure parallel mechanisms actuated with SEA .