Ty A Lasky

Singularity Avoidance for the 3-RRR Mechanism Using Kinematic Redundancy

Based on its simple structure, base-fixed actuators, high payload capacity, high accuracy, and high mechanical rigidity, the 3-RlowbarRR mechanism is a valuable planar parallel manipulator. However, the 3-RlowbarRR mechanism is known to have singular loci within its workspace affecting its use. In this paper, singularity avoidance of the 3-RlowbarRR mechanism using kinematic redundancy is presented. First, singularity analysis of the proposed 3-RlowbarPlowbarRR mechanism is described and a simple and effective redundancy resolution algorithm based on local optimization suitable for real-time control is developed. Here, the cost function in the optimization is designed to avoid the most problematic singularity configurations, where the end-effector can be locally moved even though all actuated joints are locked. Results from simulation show that the resultant 3-RlowbarPlowbarRR mechanism can be used to avoid singularities associated with the 3-RlowbarRR mechanism, and enlarges the usable workspace.

StructView: A Vehicle-Based Laser Scanning System for Roadway Structure Profile Assessment

This paper presents STRUCTVIEW, a vehicle-based system for the measurement of roadway structure profiles, which uses a scanning laser rangefinder to measure various structure and roadway features while traveling at highway speed. Measurement capabilities include horizontal and vertical clearances which can be used to support oversize vehicle permitting