Beyond Linear Control Approaches - Sliding Mode Control of Flexible Robotic Manipulator

Abstract

Flexibility in robotic manipulators offers various benefits in terms of operational speed, power consumption, maneuverability, and weight. However, these advantages lead to complex controller design. This paper presents two laws, nonlinear sliding mode control (SMC) and linear quadratic regulator (LQR) for addressing the control problem of flexible joint manipulator. The aim is to accurately track the position of link with considerable minimum oscillations, encountered due to flexibility of joint. The novelty of the derived Lagrangian-based dynamic model lies in consideration of both critical effects, gravity and viscous damping. Feedback linearization is used to linearize the system. The designed control laws are then subjected to several test inputs for comparing and characterizing their tracking performance. Comparative results reveal that SMC outperforms than LQR in trajectory tracking. Results of this research can be used in several flexible robotic manipulator (FRM) applications including medical, space and industrial automation.