Position Control System of a Two Degree of Freedom Manipulator with a Passive Joint
Hirohiko Arai and Susumu Tachi
IEEE Transactions on Industrial Electronics, Vol.38, No.1, pp.15-20, 1991.
[Abstract]
The authors propose a method of controlling the
position of a manipulator with passive joints which have
holding brakes instead of actuators. In this method, the
coupling characteristics of manipulator dynamics are used,
and no additional mechanisms are required. In this paper,
the effectiveness of the method is verified by experiments
using a prototype manipulator. The prototype is a two degree
of freedom, horizontally articulated manipulator. The first
axis is an active joint and the second axis is a passive
joint. While the brake of the passive joint is released,
the passive joint is indirectly controlled by the motion of
the active joint, through the use of dynamic coupling. While
the brake is engaged, the active joint is controlled. By
combining these two control modes, total position of the
manipulator is controlled. The experiments show that the
precise positioning of the passive joint is feasible by use
of the proposed method.