Dynamics And Operation Control Technology Of The Multi-fingered Dexterous Hand

With the rapid development of aerospace technology,the establishment and maintenance of space laboratories,as well as other operational tasks will become more and more complex.So the need for the space robot has become more urgent.To effectively perform safe and reliable operation for space task,the robot must be equipped with dexterous hand.This paper mainly studies the key issues and difficult problems related to the operate control of space multi-fingered dexterous hand.Firstly,the system composition of the developed space five-fingered dexterous hand,the design of finger and sensor system are introduced in this paper.Secondly,suitable coordinate system is established on all of the thumb joints according to the D-H method,the kinematics relationship between the Cartesian space position at the end of the thumb and the angle of the thumb joints is obtained.Then using Newton-Euler iterative algorithm and Lagrange method,respectively,the dynamic equations of the thumb are deduced.The correctness of dynamic equation is verified by the same results obtained by the two methods.Thirdly,the tendon transmission relation is modeled,an approach for the tendon tension distribution based on simplex algorithm is proposed.On such basis,two impedance control methods in tendon space and joint space are given for the position control of the thumb.Based on the aforementioned dynamic equation,the simulation for the two control methods using MATLAB Simulink is performed.The simulation results have shown that the thumb can achieve the expected motion by these two control laws,impedance control method in the tendon space has achieved better performance than the corresponding method in the joint space.Finally,in the operation of the tendon-driven dexterous hand fingertips,it is necessary to control both the contact force and the contact position,as well as to keep tendon tension at the suitable constraint bound.Therefore,with the consideration of contact force,an impedance control method for finger operation in the constrained space is proposed.A joint simulation using MATLAB and ADAMS is performed to compare the two tension constraint control mode including in the tendon space and joint space.The simulation results have shown that the tendon tension can be effectively constrained in the predefined range,both contact force and contact position between the finger and the object can be stably controlled.Thus,the validity of the method is verified.