Joint Motion Planning of Industrial Robot Based on Modified Cubic Hermite Interpolation with Velocity Constraint

• Published in: Applied sciences Vol. 11; no. 19; p. 8879
• Main Authors: Pu, Yasong, Shi, Yaoyao, Lin, Xiaojun, Zhang, Wenbin, Zhao, Pan
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-10-2021
• Subjects: Acceleration; Hermite interpolation; industrial robot; Industrial robots; Interpolation; Kinematics; knot reconfiguration; Methodology; Motion control; Motion planning; point-to-point motion planning; Polynomials; Robot dynamics; Robots; second-order continuity; Service life; Velocity; velocity constraint
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app11198879

As for industrial robots’ point-to-point joint motion planning with constrained velocity, cubic polynomial planning has the problem of discontinuous acceleration; quintic polynomial planning requires acceleration to be specified in advance, which will likely cause velocity to fluctuate largely because appropriate acceleration assigned in advance is hardly acquired. Aiming at these problems, a modified cubic Hermite interpolation for joint motion planning was proposed. In the proposed methodology, knots of cubic Hermite interpolation need to be reconfigured according to the initial knots. The formulas for how to build new knots were put forward after derivation. Using the newly-built knots instead of initial knots for cubic Hermite interpolation, joint motion planning was carried out. The purpose was that the joint planning not only satisfied the displacement and velocity constraints at the initial knots but also guaranteed C2 continuity and less velocity fluctuation. A study case was given to verify the rationality and effectiveness of the methodology. Compared with the other two planning methods, it proved that the raised problems can be solved effectively via the proposed methodology, which is beneficial to the working performance and service life of industrial robots.