Design of Fixed-Sequence Planar 5R Symmetrical Parallel Manipulators

Designing manipulation systems where the gripper has predetermined initial and final positions is an important practical consideration in modern robotics; in other words, achieving the objective of moving the payload along a non-imposed trajectory between two given positions, with the ability to change these positions periodically. One solution to the problem is to create a one-degree-of-freedom system with adjustable parts. This approach is considered optimal in terms of its simplified control and minimum energy expenditure. The merit of the solution is that manipulation systems of this type with cyclic control have only one actuator; the simple design and the control system improve the operational reliability of the mechanical system while greatly reducing the cost of it. The present work proposes a new design concept for a planar 5R symmetrical parallel manipulator. The aim of the proposed design principle is that the two input links of the manipulator are interconnected. The last one is determined in such a way that the initial and final positions of the gripper are ensured. Thus, the obtained mechanical system, having only one actuator, ensures the movement of the gripper between predetermined initial and final positions. The dynamics of the manipulation system, in particular the balancing of shaking force and shaking moment to reduce vibration in the frame, are considered in addition to the purely kinetic aspects. Numerical simulations are used to illustrate the proposed design concept.