Design and Evaluation of Cable-driven Manipulator with Motion-decoupled Joints

Proceedings of the Institution of Mechanical Engineers, Part M:

Zhu

et al. 2019

Aiming at the requirements of lightweight, low energy consumption and low inertia of the manipulators for autonomous underwater vehicles, this article presents a novel underwater cable-driven manipulator for autonomous underwater vehicles. Thanks to the cable-driven mechanism, the motors are installed remotely from joints, which can reduce the disturbance of the motion of the manipulator to the system and extend the operation time under the premise of limited energy. Cable–sheath mechanism is used to realize the motors to be fixedly mounted on the base (postposition). A prototype named Polaris-II is assembled, and experiments are carried out with the time-delay control scheme. Although the control effect of a single time-delay controller is good, there exist large errors caused by the reversing of joints. Therefore, a fuzzy compensator is designed and added to the time-delay controller to suppress the large errors. The experimental results show that the time-delay controller with a fuzzy compensator has a good inhibitory effect on the large errors while maintaining good control effect.

Section: Design and Experiments Of The Time-delay Controllermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structure design and control research of a novel underwater cable-driven manipulator for autonomous underwater vehicles

Proceedings of the Institution of Mechanical Engineers, Part M:

Zhu

et al. 2019

“…Townsend 1,2 designed a 7–degree-of-freedom (DOF) motion-decoupled cable-driven manipulator named “WAM” which now has been applied in several areas. Lee and colleagues 3–5 developed a prototype of a master–slave servo manipulator system using linkage mechanism and moving pulleys to realize motion decoupling. Zhao and Nelson 6,7 proposed a decoupled cable-driven grasper design based on planetary gear theory.…”

Section: Introductionmentioning

confidence: 99%

Design and verification of a novel motion-decoupled cable-driven manipulator

Jiang

Proceedings of the Institution of Mechanical Engineers, Part I:

et al. 2019

The joint coupling relationship was studied aiming at the motion coupling among multi cable-driven robot joints. A novel motion-decoupled mechanism is proposed and investigated. Two driving cables of distal joint traverse the modular in a specific routing. As a result, cables will wind and unwind at a certain angular along the groove in the following wheel. This design can effectively compensate the length change of cables during the rotating moving of proximal joint. Afterward, a 2–degree-of-freedom cable-driven manipulator platform using this motion-decoupled modular was set up. The verification experiment has shown a productive performance in realizing motion independence. Then, a new robust controller using time-delay estimation and fuzzy algorithm is proposed for the decoupled cable-driven manipulator. Thanks to time-delay estimation and fuzzy algorithm, the proposed controller is model-free, precise and easy to use under practical applications. Finally, contrast control experiments have been performed, and the result illustrates the superiority of the proposed control strategy.

“…7 Since driving units are placed at the base of the manipulator, cables have to go through a carved path to drive the end-effector leading to motion decoupling and degeneration of the control performance. 8 Therefore, novel cable-wound mechanism is a research hotspot recently. Cable-wound mechanism is essential to realize passive decoupling between joints, which can improve driving accuracy.…”

Section: Introductionmentioning

confidence: 99%

Design and modeling of motion-decoupling mechanism for cable-driven joints

Jiang

Hua

Advances in Mechanical Engineering

et al. 2018

With the advantages of simple structure, low power consumption, high ratio of load to self-weight, and good flexibility, the cable-driven robots are especially suitable for medical instruments and home service. Due to the alignment of cables, there is a problem of motion coupling between the manipulator joints, leading to the degradation of control accuracy. Moreover, the hysteresis and the dead zone of the cable driving unit make it difficult to control the joint accurately. To effectively solve above-mentioned motion-coupling problem, a novel motion-decoupling mechanism is proposed and investigated. An experimental setup is established to verify the kinematic decoupling characteristics. Based on the ''static friction + Coulomb friction'' model, the friction model is established and verified. Thus, studies on the friction model have provided theoretical basis for the accurate force coordinated control of the cable-driven system.