High Force Generation Using Inflatable Toroidal Soft Robot Actuators

Pneumatic and fluidic soft robotic actuators are often used for their force and motion generation capabilities, while leveraging the advantages of their soft construction, such as inherent compliance, low weight, and environmental adaptability. This paper presents a novel toroidal soft actuator design that produces increased force without increasing the external size of the actuator, the fluid pressure, or the strength of the materials holding the fluid. A model of the actuator is presented, relating design and operational parameters to axial force generation. A toroidal actuator is fabricated and compared to a McKibben actuator in axial force production. The experiments demonstrate that the toroidal design increases the force produced; in the prototype actuators, this force increase is approximately 45%. The forces estimated by the model are compared to the experimental results, and they are found to be representative, with only small errors.