tailieunhanh - Industrial Robotics Theory Modelling and Control Part 15

Tham khảo tài liệu 'industrial robotics theory modelling and control part 15', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Forcefree Control for Flexible Motion of Industrial Articulated Robot Arms 831 4. Comparison between Forcefree Control and Force Control Comparison between Forcefree Control with Independent Control and InpedanCe Control In order to illustrate the feature of the forcefree control the forccefree control with independent compensation is compared with the impedance control Hogan 1985 Scivicco Siciliano 2000 . The impedance control is the typical force control which enables the contact force between the tip of the robot arm and the object as assigned inertia friction and stiffness. The impedance characteristics are expressed by M r Dd r - rd Kd r - rd F 23 where F is the assigned force between the tip of the robot arm and the object Md Dd and Kd are the assigned inertia friction and stiffness respectively and rd rd are the objective position and the objective velocity in working coordinates respectively. The dynamics of the robot arm in joint coordinates is expressed by H q q h q q Dq Nự sgn q g q T JT F 24 and the dynamics in working coordinates is expressed by Hr q r hr q q Drr Nfir sgn r gr q jT 1 T F. 25 By substituting 23 for 25 the torque input for the impedance control is obtained by jT Hr q M- - Dd r - rd - Kd r - rd hr q q Hr q q Md - I F Drr Nfirsgn r gr q 1 26 The torque input of the forcefree control with independent compensation is derived as the same format of the impedance control. The dynamics of the forcefree control with independent compensation in joint coordinates 16 is transformed into working coordinates as Hr q r hr q q CfF - Cd Drr Nfir sgn r - Cggr q 27 832 Industrial Robotics Theory Modelling and Control By substituting 27 for 24 the torque input for the forcefree control with independent compensation is obtained by r-J Ko -1F - 1 - Cd F Nr sgn r 1 - C g q 28 By comparing the torque input of the impedance control 26 and that of the forcefree control with independent compensation 28 the following relationship is fulfilled. Hr q M d I-Dd .