tailieunhanh - Control of Redundant Robot Manipulators - R.V. Patel and F. Shadpey Part 8

Tham khảo tài liệu 'control of redundant robot manipulators - . patel and f. shadpey part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 96 4 Contact Force and Compliant Motion Control Figure General block diagram of the AHIC scheme In the next simulation the position of the tip in the Xc direction is required to be fixed while exerting a constant force equal to -100 N in the Yc direction. shows that the main task has been accomplished within a short time and from this time onwards the manipulator does not move until the MOCA additional task becomes active and successfully prevents the collision. Task Compatibility The objective of this additional task is to position the arm in the posture which requires minimum torque for a desired force in a certain direction. The formulation of this additional task is given in Section . Figure shows the results of the simulation for this case. The main task consists of keeping the manipulator tip at a fixed position in the X direction while exerting -100 N in the Y direction. As we can see in Figure the manipulator reconfigures itself to find the posture which requires the minimum torque to exert the desired force. Figure shows how the value of the objective function - task compatibility index given by -increases to reach the optimal configuration. Figure shows the force ellipsoid for the initial and final configurations. Note that the force transfer ratio along the Y direction has been increased. Figures and f show that the force and position trajectories of the main task were followed correctly. Note that the required torque is reduced when the additional task is active Figure . Schemes for Compliant and Force Control of Redundant Manipulators 97 100 80 60 40 20 0 -20 _JLA active q3min -80 JLA inactive 1 0 time s b time s Figure Simulation results for the AHIC scheme with Joint Limit Avoidance a force error N b position error mm a 98 4 Contact Force and Compliant Motion Control time s c Figure contd. Simulation results for the AHIC scheme with Joint Limit Avoidance c joint 3 .