Reduction of Contact Force Fluctuation for Rotary Wear Test Apparatus

In electric railway systems, wear of current collector devices leads to high maintenance cost. To develop a cost reduction methodology, the wear behavior of current collector materials needs to be fully investigated. However, the wear test apparatuses currently in use cannot control the contact force between materials, and the contact force fluctuates. It is difficult to classify accurate conditions of a wear transition under contact force fluctuation. To solve this problem, we propose a force control system with acceleration and velocity feedbacks to suppress the force fluctuation. The positive feedback of acceleration compensates the periodic force fluctuation at frequencies according to the sliding velocity of rubbing surfaces. The velocity feedback compensates the force fluctuation caused by resonance. The proposed control system is validated by experiments using a prototype of a rotary wear test apparatus.