Analog current-mode CMOS implementation of central pattern generator for robot locomotion

We propose an analog current-mode central pattern generator (CPG). Our circuit is based on the neural oscillator proposed by Matsuoka, well known as a building block for constructing a robot locomotion controller. We modified the Matsuoka´s oscillator to be suitable for analog current-mode implementation, and implemented it as an analog integrated circuit with current-mode low-pass filters. The oscillator circuit operates in the subthreshold region under the low-supply voltages, and thus low power consumption can be expected. We constructed a CPG circuit with four oscillator circuits. Through SPICE simulations, we confirmed that the CPG circuit generates stable phase-locked oscillation corresponding to typical locomotion of patterns of animals, and that the amplitude and frequency of the oscillation can be controlled by tuning bias currents over a wide range.