Design of a Semi-Active Semi-Passive Assistive Device for Sit-to-Stand Tasks

In this paper a robotic assistive device, aimed at assisting physically impaired individuals when rising from a sitting to a standing position, is presented. We investigate the standing up motion of aged people who requires to power support and typical standing up motion by nursing specialist. It has been shown that the contribution to the joint torques by the gravitational torques is dominant during sit-to-stand (STS) motion. To this end, a semi-active semi-passive assistive device is proposed. Design includes two parts: (a) Passive part uses auxiliary parallelograms to identify the center of mass of the system and appropriate springs connected to device to reduce the required joint torque. (b) Active part includes actuator with appropriate controller to provide the remaining joint torque. Using this device, users need insignificant force for STS movement; in particular, it improves the quality of life for individuals with difficulties in sitting down and standing up. This device is able to be portable and connected to a wheelchair.

کلیدواژه ها:

sagittal plane ، rehabilitation robot ، assistive device ، STS movement ،