Central pattern generator for pneumatic soft robots

Abstract

Soft robots open many possibilities to embed intelligence within the structure of a robot. However, central control of external valves and many control lines typifies pneumatic soft robots. This study proposes a soft pneumatic pattern generator to control the activation of two pneumatic actuators simultaneously. The concept mimics biological locomotive control, where nerve clusters distributed throughout the body control the activation of muscle fibres rather than a central brain. The brain sends out relatively simple proportional signals,  converted to more intricate patterns locally. Adapting this concept to soft robotics simplifies their typical control requirements. The proposed pattern generator controls two actuators connected to a single pressure supply, resulting in each actuator articulating out of phase with the other. The pressure curves are similar for each output, producing a balanced oscillation of the two actuators. Increasing the supply pressure increases the frequency of oscillation. This configuration is better suited to control symmetric, biomimetic locomotors than previous realisable pneumatic central pattern generators.