Comparative Analysis of a Redundant Pentapod Parallel Kinematic Machine

Parallel kinematic mechanisms (PKMs) provide high stiffness and compact structures that are suitable for a large number of applications, including 5-axis milling. This paper presents a new pentapod-based PKM with an additional redundant degree-of-freedom (DOF) capable of reaching platform tilt angles of at least 90 deg over a large workspace. The proposed new PKM has a 6DOF 4 × SPRR + 1 × PSPR architecture. It is compared herein to Metrom® Pentapod as well as to several other pertinent PKMs in terms of workspace and dynamic stiffness. It is shown that the proposed mechanism can yield a tangibly larger workspace volume, when compared to those PKMs, while maintaining its high stiffness characteristics.

Stable Platform Based on Workbench Vehicle Structure Analysis

This paper has conducted a structural analysis by workbench after establishing a stable platform for automotive three-dimensional model, primarily concerning whether the platform can provide a benchmark to meet the requirements of equipment, including the numerical analysis of whether the platform tilt angle under load can achieve the requirements as well as the scheme of improvement direction of the structure.

Horizontal Pendulum With Sudden Changes in Platform Tilt

The equations of motion for a horizontal pendulum mounted to a rocking platform are developed. Equilibrium conditions are found as a function of the platform tilt angle. The equations are transformed to describe motion about the shifting equilibrium point, and an approximation for the amplitude and phase correction of the solution is developed using the method of averaging. This approximation is used to construct an iterative map that describes the pendulum angle and rotational velocity between each instance of platform rocking. Approximate analytical solutions are compared to numerical and experimental results, and ongoing work is discussed.