Research On Structure Design And Control System Of Full Driven Five-Fingered Dexterous Hand

As the end-effector of the robot,the dexterous hand can replace human beings to work in the unknown harsh environment.The bionic five-finger dexterous hand has strong versatility and multiple degrees of freedom.It can perform various humanoid operations on the target object and can adapt to the humanoid working environment.A dexterous hand with multiple degrees of freedom is highly adaptable to the environment due to its high flexibility and can achieve a variety of humanoid operations in the unknown environment.In order to increase the flexibility and grasping ability of the dexterous hand,this paper designed a full driven five-finger dexterous hand test prototype.In the application research of the dexterous hand,the most important problem to be solved is the control problem in the grasping process of the dexterous hand.Therefore,for the grasp ing control problem of the dexterous hand,this paper proposes a force/position hybrid control strategy,and tests the strategy on the five-finger smart hand test prototype designed in this paper.The following aspects have been studies in this paper:1.A variety of dexterous hands at home and abroad are studies,summarizes the mechanical structure,degree of freedom and driving device of dexterous hands at home and abroad,analyzes the advantages and disadvantages of full driven dexterous hands and under-actuated dexterous hands,and summarizes the design requirements of dexterous hands of humanoid robots.Based on the above analysis and the design requirements of the dexterous hand,the motor drive is selected as the driving method of the dexterous hand test prototype of this article,and the test prototype is designed as a full driven dexterous hand.2.The medical anatomy of the human hand is analyzed,and a full-drive human-like five-finger dexterous hand test prototype DH-MN-I is designed.The prototype consists of five fingers and one palm.The five fingers are identical in structure,each finger has four joints,each of which is driven by an independent steering gear.One finger can achieve four degrees of freedom,consistent with the human hand.There are 20 degrees of freedom in the whole hand.Based on the structure of the dexterous hand,according to the D-H parameter method,the kinematic model of the single finger of the dexterous hand test prototype DH-MN-I was established.The forward and inverse kinematics of the dexterous finger are solved,and the workspace and jacobian matrix of the dexterous finger was analyzed.3.A control system for the full driven five-finger dexterous hand is designed.The dexterous hand control system uses STM32F103ZET6 as the main control chip,which consists of four parts: main control circuit,power supply circuit,steering control circuit and sensor circuit.The design requirements,chip selection,device selection and circuit design of each part are introduced in detail.4.A force/position hybrid control strategy is proposed.The strategy divides the grasping process of the dexterous hand to the target object into the position control phase and the force control phase.In the position control phase,in order to reduce the impact of the force generated when the dexterous hand and the target object are in contact,the trajectory planning algorithm is used for the joint to control the angle,velocity and acceleration of the dexterous hand;CFFCA(contact force feedback control algorithm)is used in the force control phase to adjust the steering speed and steering in real time based on the feedback value of the pressure sensor.The algorithm can improve the dexterous hand Stability during the crawling process.5.Finally,the whole control system is tested and verified on the full driven five-finger dexterous hand test prototype DH-MN-I.The experimental results show that the force/position hybrid control strategy proposed in this paper can control the trajectory of the dexterous hand,reduce the impact force in the dexterous hand grasping process,and control the contact force between the dexterous hand and the target object in real time,and achieve the goal of stable grasping.The dexterous hand control system designed in this paper has application value.