Additively-Manufactured Servopumps for Soft Robots

Abstract In contrast to soft robots, typical electromechanical robotic systems are able to leverage a wide range of available brushless servomotors and compatible gear reduction devices. This makes the selection of components to suit the desired application using commercial devices possible and relatively straightforward. However, for fluidic soft robotics and other electrohydraulic systems, there is a relative lack of servomotor equivalents that are low-weight, high-bandwidth, and that can provide sufficient performance at power levels of 10 to 100 W. This work presents a rapidly producible 3D-printed gerotor pump design created using fused-filament fabrication (FFF), which can be mounted to standard brushless, direct-current motors. Factors that may affect the efficacy of a 3D-printed gerotor pump are evaluated. The proposed design is demonstrated to be capable of producing pressure differentials of more than 1500 kPa, flows up to 2 L/min, and an actuation bandwidth of up to 20 Hz. The mass of the pump was 36 g excluding the motor. The presented pump is designed for use in small-scale electrohydraulic mechanisms and robots, especially fluidic soft robots as a “servopump” in applications which require a high-bandwidth, low-weight solution for the provision of hydraulic power.