Improving performance of cable robots by adaptively changing minimum tension in cables

Abstract

Higher tension in cables of a cable-driven parallel robot is preferable due to increased stiffness, higher disturbance rejection, better trajectory tracking performance and more precise motion; however, cable tension augmentation can result in saturation of actuators and high-energy consumption. This paper is devoted to investigate if dynamically changing the minimum tension in cables can allow achieving an efficient motion in term of power consumption, while preserving good trajectory tracking performance. The proposed method changes the minimum tension on-the-fly according to stiffness, dynamics of the system, and error values as feedback. A simple cable robot prototype has been used to compare traditional fixed minimum tension utilization, and the proposed approach. Experimental results showed that application of our method improves motion accuracy and reduces energy consumption of the robot.