A light cable-driven manipulator developed for aerial robots: Structure design and control research

Yaoyao Wang,Hongtao Wu,Bai Chen,Feng Ju,Jinbo Zhao,Rui Zhang

doi:10.1177/1729881420926425

Abstract

To effectively reduce the mass and simplify the structure of traditional aerial manipulators, we propose novel light cable-driven manipulator for the aerial robots in this article. The drive motors and corresponding reducers are removed from the joints to the base; meanwhile, force and motion are transmitted remotely through cables. Thanks to this design, the moving mass has been greatly reduced. In the meantime, the application of cable-driven technology also brings about extra difficulties for high-precise control of cable-driven manipulators. Hence, we design a nonsingular terminal sliding mode controller using time-delay estimation. The time-delay estimation is applied to obtain lumped system dynamics and found an attractive model-free scheme, while the nonsingular terminal sliding mode controller is utilized to enhance the control performance. Stability is analyzed based on Lyapunov theory. Finally, the designed light cable-driven manipulator and presented time-delay estimation-based nonsingular terminal sliding mode controller are analyzed. Corresponding results show that (1) our proposed cable-driven manipulator has high load to mass ratio of 0.8 if we only consider the moving mass and (2) our proposed time-delay estimation-based nonsingular terminal sliding mode is model-free and can provide higher accuracy than the widely used time-delay estimation-based proportional–derivative (PD) controller.

Highlights

In recent years, unmanned aerial vehicles (UAVs), as a kind of aerial robots, have been developing toward miniaturization
We present a light cable-driven manipulator for UAVs named Polaris-III in this work
For the precise control of our proposed cable-driven manipulator Polaris-III, we propose a time-delay estimation (TDE)-based nonsingular terminal sliding mode (TSM) (TDE-nonsingular terminal sliding mode (NTSM)) controller

Summary

Introduction

In recent years, unmanned aerial vehicles (UAVs), as a kind of aerial robots, have been developing toward miniaturization. Keywords Aerial robots, cable-driven manipulator, structure design, kinematic coupling, time-delay estimation (TDE), nonsingular terminal sliding mode (NTSM) Drive motors and reducers are directly installed in the joints which lead to large moving mass and disturbance for the UAVs. To solve abovementioned issues, scholars started using lighter robotic arms and the cable-driven manipulator.

Results

Conclusion