Classification of 3T1R Parallel Manipulators Based on Their Wrench Graph

Singularity Conditions of 3T1R Parallel Manipulators with Identical Limb Structures

Failure recovery for wrench capability of wire-actuated parallel manipulators

—In this paper, the failure of wire­actuated parallel manipulators is examined considering their failure modes. A methodology for investigating the effect of actuator/wire failures on the force/moment capability of manipulators is presented, and the criteria for full and partial recovery from these failures are established. The methodology is also applicable for the cases that the minimum norm ...

Wrench-Closure Workspace Generation for Cable Driven Parallel Manipulators using a Hybrid Analytical-Numerical Approach

In this paper, a technique to generate the wrench-closure workspace for general case completely restrained cable driven parallel mechanisms is proposed. Existing methods can be classified as either numerically or analytically based approaches. Numerical techniques exhaustively sample the task space, which can be inaccurate due to discretisation and is computationally expensive. In comparison, a...

Conceptual design of Schoenflies motion generators based on the wrench graph

The subject of this paper is about the conceptual design of parallel Schoenflies motion generators based on the wrench graph. By using screw theory and Grassmann geometry, some conditions on both the constraint and the actuation wrench systems are generated for the assembly of limbs of parallel Schoenflies motion generators, i.e., 3T1R parallel manipulators. Those conditions are somehow related...

Comparison of 3-PP̲R parallel planar manipulators based on their sensitivity to joint clearances

In this paper, 3-PPR planar parallel manipulators with ∆or U-shape base are compared with respect to their workspace size and kinematic sensitivity to joint clearances. First, the singularities and workspace of a general 3-PPR planar parallel manipulator are analyzed. Then, an error prediction model applicable to both serial and parallel manipulators is developed. As a result, two nonconvex qua...