Trajectory tracking of 2DOF robotic manipulator system based on adaptive exponential forgetting recursive least squares fractional-order PID control

This paper presents a new type of controller, called fractional-order adaptive proportional-integral-derivative (PID), that is designed to improve the stability and tracking performance of a robotic manipulator with 2DOF. Robotic arm manipulators are complex systems with nonlinear dynamics that make it difficult to maintain stability and track movements accurately. Additionally, there is a strong coupling between the arm joint position and acceleration, which adds to the complexity of the control process. To address these issues, the paper combines the exponential forgetting recursive least squares (EFRLS) algorithm with fractional-order calculus to adjust the fractional-order (FO) PID gains. The FO-EFRLS algorithm adaptation equations are derived using Lyapunov stability analysis to ensure overall system stability. The adaptive FOPID controller based on the EFRLS algorithm provides robust tracking performance for the 2DOF robotic manipulator, even in the presence of system uncertainty and disturbance effects.