Structural design and characteristic analysis for a 4-degree-of-freedom parallel manipulator

Abstract

Previous studies on parallel mechanisms have been limited to symmetrical and semi-symmetrical parallel robots. However, there is relatively little research on asymmetrical parallel robot, especially on asymmetrical parallel robots with 4 degrees of freedom. Considering of disadvantages of modern technology, a new type of asymmetric parallel manipulator is proposed based on the theory and method of position and orientation characteristic equations in this article. First, the topology theory of parallel mechanism is expounded, the robot structure is described and the position and orientation characteristic set is calculated to obtain the degrees of freedom and the coupling degree of the parallel manipulator. Then the structure coupling–reducing theory is used to realize the structure decoupling of the robot. Second, the forward kinematics solution of the parallel robot is analyzed by ordered single-open-chain method, the inverse kinematics solution is solved by the algebraic method, and a numerical example is provided to confirm the correctness of the solution procedure. Finally, the workspace of the robot is analyzed by search method. Generally, the above theoretical research provides an important reference value for the industrial design and application of the parallel robot.