Objective To study the influence of different trajectories of 3-PH/R ankle rehabilitation robot on joints and muscles. Methods The 3-PH/R ankle rehabilitation robot was simplified and imported into biomechanical modeling software by analyzing the kinematics principles. Using the actual motion trajectory of ankle rehabilitation robot as model driving, the joint and muscle forces were compared under three different trajectories, namely, dorsiflexion/plantarflexion, inversion/eversion and nutation. The correlation analysis on three motion trajectories was conducted. Results Nutation could satisfy the function of both plantar dorsiflexion/plantarflexion, and inversion/eversion, and made the ankle muscles fully exercised. The maximum difference in joint force under three different rehabilitation trajectories was 0.3 N. Different muscles had different sensitivity to trajectories. Conclusions The continuous dynamic analysis of muscle force and joint force under three kinds of rehabilitation trajectories was implemented. The results have certain theoretical significance and clinical reference value for the clinical application of ankle rehabilitation robot and the formulation of rehabilitation trajectory.

Objective Based on ergonomics and biomechanics simulation technology, the biological evaluations of human muscles and the rehabilitation strategies of foot rehabilitation robot with adjustable swing were carried out and studied. Methods The human-robot coupling model of human body and foot rehabilitation robot with adjustable swing were established by using AnyBody software. Through kinematics simulation of the coupling model, the comparison between the simulation result and the theoretical calculation result confirmed reliability of the coupling model. The parameter study of AnyBody software was used to perform the biomechanical simulation of the verified coupling model. By regarding velocity and swing of the foot rehabilitation robot as variables, the muscle activity and muscle force under different combinations of variables were analyzed. ResultsDuring rehabilitation exercise, stretching performance of the foot related-muscles was effectively trained. The influence of different velocity and swing amplitude on muscles was different, and safety range of the velocity and swing adjustment was obtained. Conclusions The combined analysis of muscle activity and muscle force under different velocity and swing was achieved. The results have certain guiding significance on clinical application of foot rehabilitation robot and formulation of rehabilitation strategies in passive rehabilitation mode.

Objective A 2-PSU/ RR parallel ankle rehabilitation robot was designed, and the biomechanical properties of human muscles were also analyzed, so as to study rehabilitation strategy of the ankle rehabilitation robot. Methods The actual workspace of the robot was obtained by numerical discrete search method, and the effect of structural parameter changes on the height of robot moving platform was explored. Then the human biomechanical responses such as muscle force and muscle mobility were obtained by human biomechanical simulation software AnyBody, so as to investigate the effect of moving platform height changes on muscle behavior. Results The robot could meet the demand of ankle plantarflexion/ dorsiflexion and inversion/ eversion motion. Appropriately increasing the initial inclination angle and decreasing the length of the fixed-length bar enabled the ankle rehabilitation robot to have a lower overall height. The height of the moving platform was decreased by 10 mm in turn, and the muscle force and muscle activity of the human body involved in the movement were decreased to a certain extent. Conclusions This study provides a new design solution for ankle rehabilitation, offers theoretical guidance for motion analysis of the ankle rehabilitation robot, and accelerates rehabilitation of the patients’ ankles by modifying the mechanism parameters.