Design and Development of a New Cable-Driven Parallel Robot for Waist Rehabilitation

This paper proposes a cable-driven parallel waist rehabilitation robot with two-level control algorithm to assist the patients with waist injuries to do some rehabilitation training. The uniqueness of the robot is that it can accurately implement the relative lateral bending, flexion, extension, and rotation of the waist on the premise of the safety. This is enabled by a mechanism design according to the motion characteristics of the human waist, and it can satisfy the need of different waist injury patients. The kinematics and dynamics of the robot are analyzed. In addition, a two-level controller is introduced to improve the accuracy of the rehabilitation training trajectory on the premise of the safety of patients and reduce the system calculation. The proportion-integration-differentiation (PID) algorithm is adopted to realize the position control in the low-level controller to ensure the accuracy of the robot. In the high-level controller, the fuzzy algorithm is used to adjust the parameters of the low-level controller according to the tension variation of cables, which ensures the patient safety and the stable operation of the robot. Finally, a prototype waist rehabilitation robot is developed for experimental calibration and performance testing. Results indicate that the designed robot system can achieve the waist rehabilitation training and the control algorithm can improve the system performance under the external disturbance.