tailieunhanh - Control of Redundant Robot Manipulators - R.V. Patel and F. Shadpey Part 11

Tham khảo tài liệu 'control of redundant robot manipulators - . patel and f. shadpey part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 142 5 AHIC for a 7-DOF Redundant Manipulator Adopting a similar scheme to that proposed in Section a solution to this problem is to add a PD feedback loop. Figure shows the block diagram of the modified controller. The following modifications have been made The Error Reference Controller ERC module which generates a Cartesian Reference Acceleration CRA has been added The position feedback which used to go to the AHIC module is now connected to ERC ml I . . t I t . . . The complete target trajectory V x x is generated online using force sensor feedback Figure shows the new modified modules which are shaded in gray. Table 5-2 summarizes the modified equations Figure Simplified block diagram of the modified AHIC controller Table 5-2 Summary of equations for new modified modules Module Equation AHIC X Md - Fe 7 - S Fd - Bd X -sX - KdS X - Xd sX ERC X X KV X- X Kp X - X RR q JTWJ Wv 1 JTW X- Jq - X Wvq Simulation Study 143 At this stage another level of algorithm development was performed for the new modified modules and functions. The complete simulation of the modified AHIC scheme was developed in the Simulink environment to study the performance of the modified scheme. The simulations consist of 5 segments which are summarized in Table 5-3. The PD gains are chosen as Kp 100 Kv 20. The results of the original AHIC scheme are compared with the modified AHIC scheme. No joint friction compensation is performed to study the robustness of the algorithms. Figure shows the comparison between the force tracking performance of the AHIC scheme as shown in Figure and that of the modified AHIC scheme. As one can see even without performing friction compensation the modified AHIC scheme is able to regulate the interaction force with limited error . However the original AHIC scheme is completely incapable of regulating the force. Note that force tracking can be greatly improved by selecting the appropriate impedance values this will be explained in