Abstract
An active-caster generates traction force in an arbitrary direction and magnitude by two motors according to direction of the drive wheel. To detect its direction, an absolute encoder is equipped on the steering shaft. However, because of structure of new type of active-caster which is composed of two tires and differential unit, the attachment position of encoder is restricted. In this paper, we propose the absolute-angle detection system using two potentiometers. The potentiometers are attached to two gears which have different in the number of teeth, while these gears are meshed with the gear rotating with the steering shaft. By rotating the steering shaft, two different voltage waveforms are detected from each potentiometer. We derive the calculation formulas detecting for the absolute-angle using two waves. In the experiment, we confirm the validity of the formulas for absolute-angle detection system.
