Brainless Quasi-quadruped Robot Resembling Spinal Reflex and Force-Velocity Relationship of Muscles

The aim of this study was to determine the conditions that allow for the generation of gait in quadruped animals using a brainless simple quasi-quadruped robot having two functions of quadruped animals. We included a reflex circuit and an actuator characteristics in the robot that were inspired by two animal functions, i.e., the spinal reflex (through the group I extensor afferent) and the force-velocity relationship of muscles. The robot, however, did not include a microprocessor or a gait generator. Our robot was able to reciprocate gait autonomously by adjusting phase differences between the limbs using only an analog reflex circuit and an actuator characteristics. Embedding two abovementioned functions in the robot allowed it to propel its body by adjusting the phase differences between the limbs.