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International Standard Serial Number:
ISSN 1001-4551
Sponsor:
Zhejiang University;
Zhejiang Machinery and Electrical Group
Edited by:
Editorial of Journal of Mechanical & Electrical Engineering
Chief Editor:
ZHAO Qun
Vice Chief Editor:
TANG ren-zhong,
LUO Xiang-yang
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Dynamics modeling of redundantly-actuated parallel
robot based on natural orthogonal complement
Abstract: In order to solve the problem of nonunique solutions of actuating forces (or torques) and potentially antagonistic internal forces, the dynamic modeling and ensuing internal forces distribution and optimization of redundantly-actuated parallel mechanisms were studied. Firstly, taking the 3RRR redundantly-actuated parallel robot as an example, the solution of displacement and velocity of the mechanism was determined based on the closed-loop vector method. Secondly, by resorting to the screw theory, a dynamic modeling approach was first proposed by means of the natural orthogonal complement, and then applied to obtain the inverse-dynamics equations of the 3RRR mechanism, that overcomes the shortcomings of both the Newton-Euler and the Euler-Lagrange methods. Finally, the driving forces (or torques) were optimized by infinity-norm solution that minimizes the maximum-driving-torque, with simulation study of a circle trajectory tracking included as a verification. The research results show that, by applying the natural orthogonal complement and the minimization of the maximum-driving-torque, the proposed method decreases the power requirement of the redundant drivers from 1.5Nm to 1.2Nm, a significant reduction by 20%; it has the advantages of both simple and efficient derivation, with few intermediate variables, and has great application and reference value for modeling of redundantly-actuated mechanical systems and subsequent control law design.
Key words: mechanism theory; dynamic equation of mechanism;redundant drive; natural orthogonal complement method; drivingforce optimization