TY - GEN
T1 - Variable power assist control of twin direct-drive motor system based on human stiffness estimation
AU - Mitsantisuk, Chowarit
AU - Katsura, Seiichiro
AU - Ohishi, Kiyoshi
PY - 2008
Y1 - 2008
N2 - This paper presents a novel sensor-less force control approach for the robot-assisted motion of human arm movements. The twin direct-drive motor system with wire rope mechanism has been developed in order to provide precise force sensation for human-robot interaction. The proposed control is obtained by using two disturbance observers combined with modal space design. In the common mode of modal space design, each motor has almost the same characteristics of the friction effect and other nonlinearity. Therefore, it is easy for the proposed system to compensate these nonlinear effects. Moreover, the bandwidth and the stiffness of mechanism can be enlarged by increasing the wire rope tension command. In the differential mode, the purity of human external force with compensation of friction force is obtained based on modal space design. This mode is useful for control interaction force of human arm movements. Variable powers assist control method based on a real-time estimation of the stiffness of the human arms is also introduced. By considering the stiffness of human arm movements, this method increases the efficiency of force control system and realizes comfortable force for human-robot interaction. The effectiveness of the method is verified by experimental results.
AB - This paper presents a novel sensor-less force control approach for the robot-assisted motion of human arm movements. The twin direct-drive motor system with wire rope mechanism has been developed in order to provide precise force sensation for human-robot interaction. The proposed control is obtained by using two disturbance observers combined with modal space design. In the common mode of modal space design, each motor has almost the same characteristics of the friction effect and other nonlinearity. Therefore, it is easy for the proposed system to compensate these nonlinear effects. Moreover, the bandwidth and the stiffness of mechanism can be enlarged by increasing the wire rope tension command. In the differential mode, the purity of human external force with compensation of friction force is obtained based on modal space design. This mode is useful for control interaction force of human arm movements. Variable powers assist control method based on a real-time estimation of the stiffness of the human arms is also introduced. By considering the stiffness of human arm movements, this method increases the efficiency of force control system and realizes comfortable force for human-robot interaction. The effectiveness of the method is verified by experimental results.
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U2 - 10.1109/AMC.2008.4516121
DO - 10.1109/AMC.2008.4516121
M3 - Conference contribution
AN - SCOPUS:77951084161
SN - 9781424417032
T3 - International Workshop on Advanced Motion Control, AMC
SP - 520
EP - 525
BT - AMC'08 - 10th International Workshop on Advanced Motion Control, Proceedings
T2 - 10th International Workshop on Advanced Motion Control, AMC'08
Y2 - 26 March 2008 through 28 March 2008
ER -