An improved D-H convention for establishing a link coordinate system

Abstract

Robot kinematic modeling needs to be based on a clear physical concept. The widely used Denavit-Hartenberg(D-H) convention requires the coordinate system to be established on the extension of axis, which leads to three problems. First, in some cases, it is difficult to obtain the kinematic model parameters. Second, there can be a mismatch between the model and the object being modeled, leading to an incorrect analysis of local joint positions. Third, it is difficult to obtain the dynamic parameters. In this paper, a general convention to solve these problems is proposed. The main characteristic of ED-H is that the coordinate system fixes on the entity, which can establish unified, intuitive and accurate modeling. Then, a theorem is given to establish coordinate frame, with the process of obtaining the parameters. Both simulation and experimental results on a 6 DOF cooperative manipulator show that the proposed procedure is efficient and practical. Finally, the characteristics of traditional D-H and ED-H on kinematics and dynamics are comprehensively compared. The proposed convention has a good guiding significance for the research and design of joint manipulator arm products.