Research On Theory And Methodology Of Underactuated Anthropomorphic Hand Design For Grasping And Manipulation

The studies in human anatomy and kinesiology have shown that although a human hand possesses a multitude of active joints,there exists inherent synergistic characteristics among these joints.It is one of challenges of current research on robotics to reproduce the rule of natural human hand movement by the method of engineering science.This dissertation carries out a systematic and in-depth research on the design and function evaluation of underactuated anthropomorphic hands.The main innovativeness about the research works are summarized as follows:A mechanical design method is developed for reconstructing human high-dimensional movement function.The daily hand movement data set is collected,and the movement characteristics of the human hand are analyzed.The analysis of human motion data shows that there are primary and secondary movement mechanisms between the joints in a digit,and the thumb and the other four fingers are poorly related,while the other four fingers have significant synergistic characteristics.According to the rule of the primary and secondary movement of the human digit,the mechanical design principle of the human digit is proposed.Based on the proposed design principle,an underactuated anthropomorphic hand is developed.The underactuated anthropomorphic hand are driven by only four motors for replicating natural human grasping functions.The feasibility of the proposed design method is verified by grasping experiments.Mechanical adaptability of underactuated mechanisms is quantitatively studied.The mechanical adaptive characteristics,which have been widely used as the unique property of the underactuated mechanism,has not been described quantitatively.Aiming at this problem,this paper defines the mechanical adaptability,and evaluates it from the effect and the cost.By analyzing the evolution of the movement and force of the typical grasping behavior of the underactuated manipulator,the external conditions and the intrinsic causes of the mechanical adaptability of the underactuated mechanism are revealed.Based on the evaluation index,the adaptability of the three kinds of typical compliant underactuated mechanisms is analyzed and compared.The results show that the underactuated mechanism with compliant coupling among joints has the best mechanical adaptability among these compliant underactuated mechanisms.A parameter design method of the underactuated mechanism is proposed to realize adaptive enveloping grasping.Through the analysis of the underactuated grasping process,it is found that there exists convergent behavior,and then the influence of the mechanical parameters on the behavior of the underactuated grasping is revealed.A step-by-step parameter design method of the underactuated mechanism is proposed,and the problem that the underactuated finger is difficult to apply enough grasp force onto the object is solved.It can avoid the occurrence of the ejection phenomenon.The experimental results verify the effectiveness of the analysis and design methods.An analytical method of in-hand manipulation capability for underactuated anthropo-morphic hands is developed.Through the comprehensive analysis of the mobility and the contact force of the hand-object system,the essential difference between the underactuated hands and the fully-drive hands in the dexterous manipulation is illuminated.The analytical method of underactuated manipulative behavior is presented.The manipulative ability of the underactuated hand is defined.An evaluation method of the underactuated manipulation ability and its algorithm are developed.The effectiveness of the analytical method is verified by the underactuated anthropomorphic hand developed in the dissertation.Analysis and experimental results show that the underactuated anthropomorphic hand is able to achieve the fine manipulation ability with large-scale range to perform the dexterous manipulation.