Under-drive Dexterous Hand Design Based On Single-finger Optimization And Reliability Analysis

With the increasing level of mechanical automation,robots have gradually become intelligent,popularized,and diversified in use scenarios,which to some extent put forward higher requirements for robot manipulators.The principle of underdrive is one of the main research directions of anthropomorphic dexterous hands,which can grasp objects of complex shapes and sizes of multiple sizes,and has strong shape adaptation ability.Based on the principle of underdrive,this paper designs a linkage-driven dexterous hand,which realizes the under-drive grabbing function by combining elastic elements,and gives the mechanical adaptability of the under-drive mechanism to the dexterous hand.The research content of this paper is as follows:Firstly,the design and working principle of under-driven dexterous single-finger mechanism are expounded,and the contact force analysis model of single-finger mechanism is established,which provides a theoretical basis for the scale synthesis of single-finger mechanism.Aiming at the problems of insufficient grasping force and unstable grasping in the envelope grasping process of dexterous hands,the NSGA-II optimization algorithm is used to synthesize the rod length of the single-finger mechanism.The optimized parameters are substituted into the theoretical model,and the changes of contact force during the grasping process of single-finger mechanism are analyzed by single finger calculation example,so as to reveal the influence of contact position and joint angle on contact force.Secondly,based on the optimized single-finger mechanism for motion accuracy reliability analysis,a kinematics model of single-finger mechanism envelope grasping limit state is established,on this basis,the influence of single-finger mechanism linkage machining error and motion pair gap on motion accuracy is considered,and the influence of motion accuracy problem on the contact force of single-finger joints is further studied.Then,build its virtual prototype around the underdriven dexterous hand design.Based on the optimized single-finger mechanism scale parameters,the single-finger mechanism is designed,and the finger mechanism adopts the integrated design idea to realize the independent drive,which provides the possibility for subsequent development and research,and designs the key components of the single-finger mechanism.Finger and palm adopt collaborative coupling design: the palm size is designed according to the geometric size of the finger,so that the dexterous hand has a reasonable grasping space and enhances the adaptability to the size of the grasp object;The use of variable palms and finger grasping enhances the adaptability to the shape of the gripped object.Finally,the dynamic simulation of the established virtual prototype is carried out,the rationality of the optimization and its design is verified,the theoretical model and optimized calculation examples are verified by the simulation results of the contact force of several common grabs,and the rationality of the overall design is verified by the grasping experimental results.