Design, analysis and method of foot trajectory generation for quadruped robots in swing-stance phase

Abstract

Purpose Legged walking robots have numerous advantages over the wheel or tracked robots due to their strong operational ability and exposure to the complex environment. This paper aims to present details about the mechanical formation and a new conceptual elliptical trajectory generation discussed throughout the paper of the quadruped robot. Design/methodology/approach Initially, a realistic CAD model of the four-legged robot is developed in Solidwork-2019. The proposed model’s forward and inverse kinematics equations are deduced using Denavit–Hartenberg parameters. Based on geometry and kinematics, manipulability and obstacle avoidance are investigated. A method of galloping trajectory is proposed for aiming the increase of upright direction impulse, which is produced by ground reaction force at each step frequency. Furthermore, the locomotion equation of the ellipse trajectory is derived by setting transition angle polynomial of free-fall phase, stance phase and swing phase and the constraints. Findings Finally, a successive simulation on a 2D sagittal plane is performed to check and verify the usefulness of the proposed trajectory. Before the development of the full quadruped, a single prototype leg is generated for experimental verification of the dynamic simulations. Originality/value The proposed trajectory is novel in that it uses force tracking control, which is intended to improve the quadruped robot’s robustness and stability.

A Review of Quadruped Robots: Structure, Control, and Autonomous Motion

“…Currently, Bezier curves are extensively employed for foot trajectory planning. Compared with previous elliptical curves [ 67 ] and cycloidal trajectories, [ 68 ] the derivative of the Bezier curve is also a Bezier curve. This property simplifies the determination of the velocity at the starting and ending positions.…”