Expanding workspace of underactuated flexible manipulators by actively deploying constraints

This paper presents the idea of employing constraints to expand the workspace of Underactuated Flexible Manipulators (UFM). The constraints are divided into two types: bilateral constraint (BC) and unilateral constraint (UC). Under the constraints the UFM is segmented into two sections: the anterior constrained section and the distal free section; moreover, the motion of the UFM is altered, i.e., the end effector of the UFM can get access to positions where unreachable previously, or, the workspace is expanded. In the paper, constrained kinematics model is developed at first. The workspace is derived thereafter. To validate the idea, an underactuated wire-driven serpentine manipulator is built. In the experiments, the two types of constraints are applied. Experiment results agree well with the simulation results.