Design and Manufacturing of Motor-Tendon Actuator for a Soft Starfish-Like Robot

A motor-tendon actuator is one of the widely used actuators in a soft robot that utilizes rope/wire connected to a motor. Soft tendon actuator is an alternative solution to the shortcomings of several other types of actuators such as pneumatic-network actuators, and shape memory alloy (SMA) actuators. This study presents the design process and manufacturing of motor-tendon actuators that can be used as an actuator for a starfish-like robot. Five soft motor-tendon actuators will be developed by varying the dimensions and composition of silicone rubber material. In the manufacturing process, a casting method is used to build four soft legs of the starfish-like robot. The tests for actuator bending are performed on the five developed motor-tendon actuators. Based on the test results, the bending angle of the proposed actuator is affected by the dimension of the soft leg, while the flexibility of the actuator is influenced by tendon thickness. Based on the composition of the soft leg material, the smaller the ratio of the composition of silicon rubber to the catalyst, the shorter the pot life material, and the faster curing time.