A Modified Super-Twisting Sliding-Mode Control for Reducing Robot Arm Dynamic Vibration

The main challenges in controlling robot arms in rescue robots or robotic-assisted surgery are dynamic vibration and overshoot. This paper introduces a new technique to address these issues. To validate the control performance of the proposed technique, it is compared with other control strategies. A BLDC motor drive module, equipped with BLDC motors, has been developed to evaluate three different speed control techniques for a robot arm. Among the three control techniques tested, conventional PI control reaches the set point but exhibits high dynamic vibration, high overshoot, and poor tracking performance. This issue was mitigated by using Super-Twisting Sliding-Mode Control (ST-SMC), which reduces dynamic vibration but still results in high overshoot. Consequently, the proposed controller, named Modified Super-Twisting Sliding-Mode Control (MST-SMC), was developed to address the overshoot problem associated with ST-SMC while retaining the benefit of reduced dynamic vibration. The test results conclusively demonstrate that MST-SMC delivers the best performance, characterized by low amplitude of vibration, minimal overshoot, and the shortest settling times. Additionally, it achieves superior tracking performance.