Design of a Link-Less Hyper-Redundant Manipulator and Composite Shape Memory Alloy Actuator

The design of a link-less hyper-redundant miniature manipulator driven by high strain SMA (shape memory alloy) actuators is the focus of this research. The manipulator is composed of four identical modules connected in series, each providing three degrees of freedom from three symmetrically positioned actuators. The manipulator is withheld by the action of a positive air pressure flow injected in structure at the base of the manipulator. The internal pressure give the manipulator its stiffness, provides the return force require by the SMA actuators and, to a certain extent, acts as a coolant during post-actuation. High strain rates are achieved by submitting the SMA material to bending stressed rather than pure tension. The controller is designed based on the principle of binary actuation, which eliminates the need for sensing equipment and feedback control. The compliant nature of the manipulator and its lightweight construction enable the manipulator to perform complex tasks in constrained environments