Angular measurement with a gear wheel as a material measure - Extension as absolute sensor

This study examines the angle-specific tooth signature of a gear wheel and describes the possible use for monitoring the gearbox condition. The tests were conducted on a gearbox test stand with two 1-stage gearboxes equipped with a magnetoresistive sensor, which measures the angle using the gear wheel as a material measure. This new usage of a gear wheel and its specific properties are described. The gearboxes were driven by 30 kW asynchronous motors and tested in four quadrants with varying speed and torque conditions. The raw signals were processed using Matlab®. The sensor concept generates a sine-like signal for each tooth of the gear wheel. The high and low peaks of the sine-like wave were extracted and compared to analyze the reproducibility of the angle-specific tooth signature. The results show that the high and low peaks at one tooth of one sensor have a standard deviation of 0.0014 V over 10 revolutions and at different operating conditions, demonstrating the reproducibility of the angle-specific tooth signature. To further utilize this signature, a procedure is presented to identify an absolute reference with these signals, and the potential usage of the angle-specific tooth signature for absolute position detection is described.