Control of Snake Like Robot for Locomotion and Manipulation

Environment in which human being works has spread in the various directions by development of technology in recent years. In many cases, such field is accompanied with danger, then the necessity for work robots in such space is increased. Furthermore, the multi functional robot which can do many tasks is desirable in such environment. Therefore, development of the robot which has redundancy was investigated and developed, to name just a few. [1][2][3][4] As a model of the snake type robot treated in this paper, it is assumed that the robot has passive wheels at each link and a friction coefficient to the tangent direction of the body link is 0 and normal one is infinity, i.e., the snake robots has constraints of not sliding to the normal direction of the wheels. (See Fig. 1) In control of this type of the robot, singular avoidance of postures is one of the important problems where the singular posture means the state when it is impossible for a robot to move further. As typical examples, the shape of a straight line or arc are known.[6][5](Fig 2) In the last paper, we proposed a winding control technique using a physical index of horizontal constraint force. [7] When it approaches a target point, it is necessary to raise a head and to work like a manipulator. However, depending on the number of links to raise, the degree of freedom may be insufficient or conversely redundant. Therefore, a technique of the head configuration control using a criterion function which is not influenced a number of links to raise was