Operation mode analysis of 3-RPS parallel manipulators based on their design parameters

Abstract

It is known that a 3-RPS parallel manipulator with an equilateral triangle base and an equilateral triangle platform has two operation modes [1] whereas a 3-RPS cube manipulator with a cube shaped base and an equilateral triangle platform has only one operation mode [2]. This behavior is indeed a result of the difference in the architectures of these manipulators. Therefore, this paper deals with the operation mode analysis of 3-RPS parallel manipulators based on their design parameters. Study's kinematic mapping is exploited to derive the constraint equations of the manipulators under study. A linear combination of the constraint equations independent of the joint variables is compared with a general quadric in the 7-dimensional projective space P 7 to obtain some relations between the design parameters of 3-RPS manipulators with coplanar revolute joints, such that those manipulators have two operation modes. Some special cases and a numerical example are considered to emphasize the proposed approach and highlight the contributions of the paper.

A Novel Three-SPR Parallel Platform for Vessel Wave Compensation

“…The motion model of the parallel 3-SPR compensation platform is established by using the same structure size as the 3-RPS platform above. Comparing with the compensation platform based on the 3-RPS parallel structure, the equation sets of the 3-SPR compensation platform is more complex because the revolute joint constraint of the 3-SPR platform is attached to the moving platform [18]. The kinematic of the 3-RPS compensation platform is relatively simple, and the pose of the moving platform corresponds to the solution of leg length [19] Therefore, we can use a method of "inverse solution" to calculate the workspace of the parallel 3-SPR compensation platform.…”

“…When the moving platform of the 3-SPR compensation platform performs a compensation movement, the central point of the moving platform will have a large horizontal displacement relative to the vertical line passing through the central point of the fixed platform. This movement is called platform parasitic movement [18]. The amplitude of platform parasitic movement is proportional to the deflection angle of the platform.…”

Rigid-flexible coupled dynamics analysis of 3-revolute-prismatic-spherical parallel robot based on multi-software platform

“…where q is a generalized coordinate array, u is a generalized velocity array, l is a constrained reaction force and force array, F is a system dynamic differential equation and a user-defined differential equation, and f is an array of algebraic equations describing constraints. For example, the state vector of the defined system is y = ½q T , u T , l T T ; equations (22) to (24) can be written as a single matrix equation…”

“…The .mnf generated in ANSYS is read in ADAMS/View, and the upper and lower links in the multi-rigid dynamic model are replaced with flexible bodies, that is, the rigidflexible coupled dynamics model of 3-RPS parallel robot is generated. [21][22][23] Displacement changes at the end of the claw…”

Investigation of an Underwater Vectored Thruster Based on 3RPS Parallel Manipulator

“…is parallel mechanism is a strong coupled nonlinear structure, so its motion control is too complex to use more widely [44][45][46][47]. Despite its advantages, the 3RPS parallel manipulator also needs to overcome some problems that would restrict the development and application of the thrust-vectoring mechanism.…”