A biologically inspired finger-like mechanism similar to human musculoskeletal system is developed based on Shape Memory Alloy (SMA). SMA actuators are inspiring the design of a modular finger part with compact and compliant actuation. This paper describes a three-segmented finger-like mechanism. This mechanism is composed of six bending Shape Memory Alloy (SMA) actuators. As a result, our finger mechanism is compact and compliant. The insider three SMA actuator are used for finger flexion while the outsider three SMA actuators are for extension. Each segment of this mechanism can be bent and/or extended independently by actuating a corresponding bending SMA actuator. Furthermore, full bending motion can be achieved by applying coordinated control of the three SMA actuators. Bending and stretching motions of the proposed mechanism are finally demonstrated. The work space of the three-segment finger is studied to verify the reachable points by the end tip. The kinematic model is developed to study the motion of the mechanism. The performance evaluation is executed using force sensor and a temperature monitoring of the corresponding SMA actuators. The simulation and experimental results indicate that the SMA-based finger module can achieve effectively the desired motions as designed. |
