Architectural singularities of parallel mechanisms with prismatic joints due to special designs of platform shapes

Abstract

Abstract. Singularity is an inherent property of robotic manipulators. A manipulator becomes singular when it gains or losses degrees of freedom at a particular configuration. In this work, a type of singularities caused by special shapes of platforms, either the mobile or the base platform, is addressed. This type of singularities pertains to the architecture singularity, but associated only with special shape designs of base and mobile platforms and spans in the whole workspace, which is referred as shape singularity. The paper provides formulations of shape singularity. The geometry and algebra properties of shape singularity are analyzed. Three examples of shape singularity identification for parallel mechanisms with prismatic joints are included, one for 3-DOF planar mechanisms, the others for 3-DOF and 6-DOF spatial mechanisms. The application of shape singularity in adjustable compliance mechanism design is illustrated.

Multi-objective optimization of a redundantly actuated parallel robot mechanism for special machining

“…Yang et al (2019) invented a new three degrees of freedom (DOF) asymmetric translational parallel manipulator that is adapted to pick-and-place operation under heavy load. Wu et al (2019) provided formulations of shape singularity and illustrate the application of shape singularity in an adjustable compliance mechanism de-sign. Therefore, the research on redundantly actuated parallel mechanism is great valuable for special machining.…”

Kinematics analysis of a four-legged heavy-duty robot with a force–position hybrid control servo actuator in a parallel-executed cylinder system

“…Similar to research on related topics, scholars mostly assume that the distance between the foot and the rolling axis of the hydraulic actuated four-legged robot studied in these subjects is larger, and the driving torque required by the design is larger under the same foot end force (Xu et al, 2019). Gor et al (2018) analysed in detail the impact of supporting leg impedance on leg gait stability and efficiency.…”