Tham khảo tài liệu 'control of redundant robot manipulators - . patel and f. shadpey part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Testing and Verification 127 To verify and test the integration of the controller modules we recall that if the AHIC scheme is successful the manipulator acts as a desired impedance in each of the 6 DOF s of the C frame. Figure shows the desired impedance in position-controlled and force-controlled axes respectively. In order to verify the operation of the AHIC scheme two simple one-dimensional simulations for the position and force controlled axes were used see Figure . a Figure Desired impedance a position controlled axis and b force-controlled axis To check the correct operation of the controller in position-controlled directions all axes were specified to be in position-control mode. A 1 N symmetric step force in all three X Y and Z dimensions of the C frame was applied to both systems. The desired impedance values can be selected arbitrarily at this stage because we only need to compare the responses of the two systems. The impedance values used for this test in all 6 DOF s of the C frame were . rd r Ì I ld 1 Ns TSd Ị 1000 N M 257kg B 1100 K 11000 m m ữn Figure shows the plots of the changes in the position of the origin of the frame T along X and Y axes of the C frame. The same test was performed for the force-controlled direction with the following values rd T d f f s f f f N d M 257kg B 1100 K 11000-- F 20N m e m Figure compares the force history of the AHIC after contacting the sur- 128 5 AHIC for a 7-DOF Redundant Manipulator face with that of the pure-impedance simulation in Figure . As one can see the response of the AHIC simulation is very close to that of the pure impedance simulation. The possible sources of the small discrepancies are as follows a b Figure Simulink one-dimensional simulation of the desired impedance a position-controlled axis b force controlled axis. As mentioned in Section the presence of the singularity robustness term Wv introduces some error. The simulation of the AHIC scheme is
