Intelligent and classic Control of Rehabilitation Robot with Robust PID and Fuzzy Methods

Rehabilitation of patients with neurological and spinal cord injuries is conducted for improving brain flexibility, as well as the patient performance. The performance of rehabilitation robots requires high standards of safety and reliability due to their direct interaction with humans during therapeutic motions. One of the simple robot arms is a two-degrees-of-freedom robot manipulator that its function is considered as the basis for the performance of other arms. Due to the nonlinear dynamics, the control of two-degree-of-freedom arm is challenging. At first, a robust PID controller was used, due to its simplicity and low-cost. Subsequently, the Mamdani and Sugeno fuzzy controllers were designed, in which two inputs, called error and error derivative, and torque output were included. Finally, the hybrid fuzzy controller was designed as the first joint of the robot by using robust PID control, and the second joint by using the Mamdani fuzzy control. Comparison of control methods showed that the fuzzy Momdani fuzzy controller at both axes can provide the most limited torque for the joint engines. In addition, the most accuracy of working point was the fuzzy hybrid control. Sugeno control showed the maximum speed and torque.