Model-based Control of a 3UPS+1RPU Parallel Robot for Knee Rehabilitation

Abstract

The development of rehabilitation robots today represents a vast field for developing control techniques, mainly in devices intended for the rehabilitation of lower limbs. This article compares three control methodologies using the dynamics of a parallel manipulator type 3UPS + 1RPU to analyze the behavior when following a predefined trajectory. It begins with analyzing the inverse and forward kinematics and the components of the robot dynamics. Then, in the same way, the restrictions and configurations are analyzed to avoid the singularities of the system. Finally, the performance index based on the integral of the squared error is used to compare which controller is more reliable, as well as the energy expenditure of the actuators when performing the prescribed task. All this is under a simulation environment that allows verifying the robot’s behavior.