Gait transition by tuning muscle tones using pneumatic actuators in quadruped locomotion

The development of an oscillator controller for a quadruped robot with antagonistic pairs of pneumatic actuators is reported. Periodic motions of the legs switch between the swinging and supporting stages based on the phase of the oscillators. The oscillators receive touch sensor signals at the end of the legs as feedback when the leg touches the ground and compose a steady limit cycle of the total periodic dynamics of quadruped locomotion. And also muscle tone is adaptively controlled according to the dynamic state of the main body. This system can generate gait transition from one to another by changing locomotion speed and muscle tone. The effectiveness and performance of the proposed controller were evaluated with numerical simulations and experiments with the hardware.