Research On Optimal Design Of A New Flexible Humanoid Manipulator

As the end effector of robot,manipulator establishes the connection between robot and external environment.The development of manipulator affects the application of robot in all walks of life.For decades,researchers have been working on the design of universal and flexible manipulator,which can grasp various types of objects in many scenes.However,the movement and function of most manipulators are very single,and the flexibility is not enough,especially the fingertips can not grasp small objects like human hands.The mechanical and electrical system of the manipulator with good flexibility has poor integration,low reliability,high cost and sophisticated control mechanisms.In addition,whether the traditional rigid manipulator or soft manipulator,its stiffness is generally larger or smaller,which seriously limits the versatility and reliability of the manipulator.Therefore,in view of the shortcomings of various types of manipulator at present,this paper aims to realize the high flexibility,universality and reliability of the manipulator.From the perspective of bionics,a new type of flexible humanoid manipulator optimization design research is carried out.The research contents mainly include:(1)Referring to the physiological structure of human fingers,a new type of two finger manipulator is designed,which uses the pneumatic artificial muscle to drive the metacarpal joint and phalangeal joint of the hand independently.It can realize two types of grasping modes,fingertip grasping and envelope grasping,and accomplish most of the daily grasping tasks like human hands.At the same time,the key parts of the manipulator are designed,and the force transfer performance of the manipulator is optimized.(2)Based on the two types of grasping mode of manipulator,the analysis and optimization design are carried out.Firstly,based on the finger statics analysis,the relationship between the contact force and the torque of each joint is obtained.In view of the unstable situation of negative contact force,the optimal size of each knuckle is determined by the measurement of human hand size.Then,based on the potential energy model of the stiffness matrix,the fingertip grasping analysis is carried out to determine the reasonable size range and the best shape of the fingertip.Finally,the relationship between finger position and object size is determined.(3)The forward kinematics of fingers was analyzed.The inverse kinematics model of fingers is completed,and the cloud map of finger workspace is obtained.In this paper,the problem of finger dynamics is divided into three parts.Then,based on ADAMS software,the grasping motion simulation of manipulator is carried out to verify the rationality and effectiveness of manipulator design and optimization.(4)The equivalent spring model of the manipulator flexible actuator is established,and the stiffness model of the antagonistic joint is solved.The grasping stiffness of the manipulator is evaluated.A quasi-static model is proposed for the artificial flexible manipulator designed by us,and the analytical expression of the grasping flexibility of the manipulator is given.(5)We have completed the construction of the manipulator prototype,and carried out the manipulator grasping experiments on common household objects.The experimental results show that the flexible humanoid manipulator designed by us has good grasping stability,high flexibility and generality,and can realize the stable grasping of various common size objects in daily life,and the size range of grasping objects is wider than that of ordinary manipulator.