CPGs with Continuous Adjustment of Phase Difference for Locomotion Control

Abstract

The central pattern generator (CPG) has been found to be a real, existing neuron controller for the locomotion control of animals and it has been used on bio-inspired robots widely in recent years. However, research on the adaptability of CPG-based locomotion control methods is still a challenge. In particular, the performance of the CPG method on quadruped robots is not good enough in some situations compared with the traditional force control methods. In this article, we adopt a CPG method in which phase difference between oscillators can be arbitrarily adjusted, and we try to improve the CPG's applications in quadruped robots in some aspects. One aspect is static walk gait locomotion, in which we try to add a transition state in the CPG network to enhance the static balance of the robot. Another aspect is gait transition. Compared with the traditional abrupt gait transition, we try to realize a continuous gait transition between walk gait and trot gait to decrease the fluctuations of the robot. The improved CPG method is tested on a quadruped model and it shows positive results with regard to the improvement of static walk gait and gait transitions.

Šešiakojo roboto judėjimo energetinio efektyvumo tyrimas

“…al. 2006 6) čia E k -vienos pavaros kinetinė energija, Ipavaros inercija, ωkampinis pavaros greitis. Kai kuriais atvejais vien kinetinės energijos įvertinimo neužtenka, todėl yra skaičiuojama ir potencinė sistemos energija.…”

Gait Generation and Transition for Bipedal Locomotion System Using Morris-Lecar Model of Central Pattern Generator

“…They realized a continuous gait transition between walk and trot gaits in a quadruped robot. Specially, they used an adaptive frequency version of Hopf nonlinear oscillator as CPG, where its intrinsic frequency was adapted by sensory feedbacks [21]. Zhang et al [22].…”

Three-dimensional walking of a simulated muscle-driven quadruped robot with neuromorphic two-level central pattern generators

“…33 RG and PF parts are mainly responsible, respectively, for conditions (A): phase transition and (B): synergistic activation of multiple muscles. Since the CPGs used in the simple quadruped models and robots [9][10][11][12][13][14][15][16][17][18][19][20][21][22] are not explicitly split in the two layers of RG and PF, they have difficulty with being simultaneously responsible for both (A) and (B). We believe a more realistic CPG model is required to satisfy the two conditions and achieve 3-D locomotion.…”

“…Therefore, a quadruped robot with a CPG can safely locomote over irregular terrain without explicitly changing its leg trajectory, 9 which is a common method for quadruped robots without CPGs. Many mammalian quadruped simulated models [10][11][12][13] and robots 9,[13][14][15][16][17][18][19][20][21][22] with CPG models have thus successfully achieved quadrupedal locomotion. They made significant contributions to recognizing the value of CPG for quadrupedal locomotion; however, the mechanisms and nervous systems of the quadrupeds were fairly simplified to allow them to safely locomote.…”