Design And Control Of Humanoid Rigid-flexible Coupled Dexterous Hand

Design of humanoid dexterous hands is an interesting and challenging field of robotics.Researchers usually adopt high-rigidity multi-degree-offreedom joint designs to make human-like dexterous hands with strong load capacity and certain grasping dexterity.However,this method usually relies on a complicated drive transmission mechanism and a high-precision control method,and lacks good compliance.In recent years,the rise of soft robotics technology provides a new method for designing a rigid-flexible coupled human-like dexterous hands with simplified structure and control methods.In this thesis,aiming at achieving dexterous movement,compliant grasping,simplifying the drive transmission structure and control methods,we develop a rigid-flexible coupled dexterous hand.This thesis firstly explores how the human hand realize the diversity of grasping gestures in terms of the finger structure of the human hand,and the palm structure.Based on the soft robotics technology,a flexible pneumatic soft finger is designed.Then,a palm joint with large range of motion and load is realized by the rigid mechanical structure design method.The soft pneumatic fingers and rigid palm joints realize the compliant grasping and dexterous movement ability of the dexterous hand,and simplify the drive transmission structure and control method of the dexterous hand.To achieve the necessary rotational freedom and control requirements of the dexterous hand,a wrist joint is introduced for our hand.In addition,the mechanics and range of motion of our dexterous hand are tested and analyzed.Grasping stability is another important ability of dexterous hands.In order to achieve the stability of grasping and satisfy the control requirements of dexterous hands,this thesis designs a pneumatic-driven control system with feedback control capabilities.The classic control strategy is compared and analyzed,and the bang-bang control strategy is utilized.Our control system consists of 5 pneumatic drive subsystems and1 control subsystem.The performance of our control system,including anti-interference,steady-state response and dynamic response abilities,are characterized.Based on the characterizations of human hand,a multi-finger palm-topalm experiment,a dexterous and compliant grasping experiment for the standard test set,and a dexterous operation experiment are performed.The results demonstrate that the humanoid dexterous hand can complete all finger-to-palm movements,realize 30 of the 33 grasping postures in the standard test set,and complete the grasping and pouring operation experiments of 500 g water bottles.The experimental results further show that the developed hand has excellent multi-finger matching ability,dexterous movement and compliant grasping ability,and can maintain the air pressure stability with control systems.