Design and Simulation of High-human-machine Cooperation Sit-to-Stand Assistive Device

Sit-to-stand (STS) is considered the most common and functional activity in daily life and the basis for other activities. Healthy adults perform an average of 60 ± 20 STS transfer movements every day, while the elderly and patients with lower limb disorders could not complete the movements very well due to limb pain, muscle weakness, partial loss of motor control functions, and physical defects in joints. This paper presents a high-human-machine cooperation STS assistive device by studying law of motion of STS of the human body. Kinematic analysis of the assistive device was carried out, the relationship between the linear actuator and the position of each joint was established. According to the trajectory of human body obtained from the STS transfer experiment, the length variation of the linear actuator is obtained through the inverse kinematics. Finally, through Adams kinematics simulation, the trajectories of the mechanism were verified.