B. Experimental result of compliance motion
The purpose of this experiment is to verify the robot can detect a user's motion intention and assist a user to walk.
During the experiment, the user hold the folded robot arm and gave several arbitrary motion intentions (including forward, backward, left shift, right-shift, moving left front, right front moving) to verify whether the robot can follow the user’s motion intent. Fig. 10 shows the snapshot of the experiment. Fig.11 illustrates the relationship of user’s force on the X-axis direction and robot velocity measured from shaft encoders of each wheel. The blue solid line is the force data on the X-axis measurement from the force/torque sensor and the red dotted line is the velocity and the green dotted line is the torque around Z-axis. It is shown that the robot motion is compliant to the force (motion intent) as desired. Fig.12 shows the relationship of user’s force in Y-axis and measured robot velocity in Y direction. The blue solid line is the force data in the Y-axis from force/torque sensor. On top of Figs. 11-12,the duration a-l correspond to the (a)-(l) of Fig. 10. A video clip of this experiment can be found in [13].