Abstract: This study deals with the residual vibration reduction control after
catching a falling steel sphere by a two-link catching flexible robot arm. The
two-link catching flexible robot arm consists of a first rigid link, a second
flexible link and a cup mounted to catch the falling steel sphere. The
flexibility of the second flexible link is effectively utilized to reduce the
shock owing to the contact between the falling steel sphere and the cup. Then,
the equation of motion of the two-link catching flexible robot arm is obtained,
and the cost function for the residual vibration reduction control after
catching the falling steel sphere is defined as a function of the parameters of
the second joint angular velocity profile. By making the contour map of the
cost function, the optimal parameters of the second joint angular velocity
profile is obtained. The residual vibration reduction control is implemented by
the feedforward control based on the second joint angle trajectory with the
optimal parameters. Furthermore, the numerical calculations and the experiments
have been carried out, and it is confirmed that the residual vibrations of the
second flexible link after catching the falling steel sphere can be extremely
reduced.
