Experiments with a Continuum Robot Structure

A continuum arm prototype was designed and implemented using two different shapes: cylinder like and cone like. This new robot is actuated by stepper motors. The rotation of these motors rotates the cables which by correlated screwing and unscrewing of their ends determine their shortening or prolonging, and by consequence, the tentacle curvature. The kinematics and dynamics models, as well as the different control methods developed by the research group were tested on these robots. The lack of no discrete joints is a serious and difficult issue in the determination of the robot’s shape. A solution for this problem is the vision based control of the robot, kinematics and dynamics. An image – based visual servo control where the error control signal is defined directly in terms of image feature parameters was designed and implemented. In this paper, we analyze some mechanical capabilities of this type of continuous robots. We present the structure of the tentacle robot, it’s kinematics model and the results for a series of tests regarding the mechanical behaviour of the robotic structure.