Abstract
A new design concept of space manipulator has been proposed, which is called Torque-unit Manipulator (TUM) . Each joint of TUM is free and a device which is called “torque unit” is equipped on each link. The “torque unit” can be made easily of a DC motor and a disc, for example. Position-controllability of the links of TUM has been shown with conventional control laws for manipulators, however some of state variables cannot be controlled when such control laws are used. When such control laws are used, positions of the links are controlled to desired positions but the angular velocities of the discs usually do not come to zero and result to be constant. The reason is that TUM is a kind of nonholonomic system and hence the angular velocity of each disc at each time depends on the trajectories of the links. In this paper, a progress is made in the study of trajectory planning for 2-dimensional N d.o.f. TUM to control the positions of the links and the angular velocities of the discs. A possibility is considered to control the position of each link to desired position and the angular velocity of each disc to desired constant value which is not zero.
