Design of Three-finger Capturing Mechanism Using Artificial Muscles of Twisted and Coiled Polymer

Abstract

The multi-finger mechanism has more degrees of freedom (DoFs) and it can capture non-cooperative targets with complex shapes in space. How-ever, traditional multi-finger mechanisms driven by servomotors have these disadvantages of large volume, heavy weight, high energy-consumption, and poor shock absorption, which are difficult to be used for operations in space. This paper proposes a novel three-finger capturing mechanism using twisted and coiled polymer (TCP) muscles. Each finger is a redundant serial-parallel hybrid mechanism with four DOFs, which is driven by five TCP artificial muscles. Type synthesis of the parallel part of the finger’s mechanisms is carried out based on the generalized function (GF) set theory. The forward and inverse kinematic equations of the entire finger mechanism is derived. The prototype of the three-finger capturing mechanism has been manufactured. Finally, the experiments of capturing a nozzle model of the apogee kick engine (AKE) verify the design and kinematic model of the three-finger capturing mechanism.