Grasping Characteristics Analysis And Open Door Grasp Planing Of Underactuated Three Finger Hand Using In Nuclear Disaster Rescue

As the executive mechanism of the nuclear disaster relief robot, conducting the research of the end-effector grasp is significant. Underactuated three-finger hand has the advantage of simple control, high reliability and shape adaptability. According to the end-effector grip planning and analysis, this paper has done the following work:Kinematics analysis was carried out on the underactuated three-finger hand, and using the coordinate transformation matrix, establish underactuated three-finger hand coordinate system, analysis the angle of two knuckles and three finger. The kinematics model of the three-finger hand is derived to get the relation of gearbox driving force and the contact force between the fingers and object. The dynamics model of the door closer is derived with the Lagrange approach which is benefit to open door.The relationship of contact deformation and the contact force is applied with the Hertz contact model. The contact forces analysis problem can be transformed into a nonlinear constraint optimization problem with the complementary energy minimal principle. Then the nonlinear constraint optimization problem can be solved efficiently with the optimized method of augmented Lagrange method. The question of how to solve the contact force has been resolved with the condition of actuator forces and external forces.The mathematical model has been made to solve the angle range of the first knuckle and the second knuckle with twisting the doorknob in different ways. To analysis the grab stability with the perspective of gripping force, spring and friction. Two different approaches to open the door are compared. Different ways to grasp the door knob are described under different angle of the plane between the three finger hand and door knob.To verify the feasibility of movement by establishing steel wire rope pulley system through ADAMS Cable module. It established the joint simulation platform for underactuated three-finger hand based on ADAMS and MATLAB/Simulink software to verify the feasibility of finger rotation. To verify gripping force model by dynamic analysis based on ADAMS software. For ejection phenomenon may occur during the grab, appropriate solutions has been proposed.