Design and Kinematic Analysis of a Novel Planar Parallel Robot With Pure Translations

Abstract

The structural synthesis of a group of parallel mechanisms can be established by an exhaustive enumeration of all feasible kinematic chains based on the screw theory. However, reliable kinematic limbs can provide mobility constraints for some unqualified supporting legs to guarantee the degrees-of-freedom feasibility of the parallel robots. A systematic design approach is presented for a family of planar single-loop parallel mechanisms with the consideration of infeasible kinematic chains. Different from the other design approaches for single-loop linkages, the fixed and moving platforms are predefined in this research to distinguish different kinematic limbs. The special parallelogram linkage mechanism is incorporated due to its equivalent translation capacity. Three categories of singularity configurations are investigated based on the detailed kinematic models. The reachable workspace is obtained through the spatial search methodology. Several novel kinematic error model associated performance indices are proposed in this work and examined on a translational parallel manipulator. Experiments are carried out and compared to testify the effectiveness of the kinematic analysis and proposed position-based controller.

Direct and Inverse Kinematics of a 3RRR Symmetric Planar Robot: An Alternative of Active Joints

“…This paper proposes a solution that preserves the advantages of parallel robots while reducing the complexity of kinematic equations by a vector analysis. The presented algorithm offers two alternatives: the traditional one, which requires knowledge of the orientation phi of the end-effector and is used in various applications as pick and place [37,38], or medical rehabilitation [39,40]. There is also an alternative that eliminates the need to know this orientation, using instead an optimization method, useful in monitoring applications like conventional or thermal cameras [41].…”

“…The main contribution of this work is the proposal of a new alternative for the implementation of planar 3RRR robots. This proposal has ( 15)- (17) as direct kinematics and ( 25), (31) and (40) as inverse kinematics. For applications where phi is not necessary, the application of inverse kinematic systems is proposed.…”