A Bio-Inspired Control Strategy for Locomotion of a Quadruped Robot

Abstract

Abstract:In order to effectively plan the robot gaits and foot workspace trajectory (WT) synchronously, a novel biologically inspired control strategy for the locomotion of a quadruped robot based on central pattern generator-neural network-workspace trajectory (CPG-NN-WT) is presented in this paper. Firstly, a foot WT is planned via the Denavit-Hartenberg (D-H) notation and the inverse kinematics, which has the advantages of low mechanical shock, smooth movement, and sleek trajectory. Then, an improved central pattern generator (CPG) based on Hopf oscillators is proposed in this paper for smooth gait planning. Finally, a neural network is designed and trained to convert the CPG output to the preplanned WT, which can make full use of the advantages of the CPG-based method in gait planning and the WT-based method in foot trajectory planning simultaneously. Furthermore, virtual prototype simulations and experiments with a real quadruped robot are presented to validate the effectiveness of the proposed control strategy. The results show that the gait of the quadruped robot can be controlled easily and effectively by the CPG with its internal parameters; meanwhile, the foot trajectory meets the preplanned WT well.

A Human-assistive Robotic Platform with Quadrupedal Locomotion

“…After the leg sequence planning, the leg joint trajectory generating is a following step to create the motion for each joint. Current research in joint trajectory generation is based on inverse kinematics with DH convention [22]. Nonetheless, with only this classic convention, the smoothness of the trajectories has a big compromise.…”

Special Feature on Bio-Inspired Robotics

“…In order to effectively plan the robot gaits and foot workspace trajectory (WT) synchronously, Zeng et al present a novel biologically inspired control strategy for the locomotion of a quadruped robot based on central pattern generator-neural network-workspace trajectory (CPG-NN-WT). A neural network is designed and trained to convert the CPG output to the preplanned WT, which can make full use of the advantages of the CPG-based method in gait planning and the WT-based method in foot trajectory planning simultaneously [8]. Ba et al propose a position-based impedance control method for the hydraulic drive unit on the joints of bionic legged robots.…”

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

“…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.…”

“…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.…”