Accurate measurement of angle position at high angular velocities

Error sources in measurements of angle position under static conditions often contribute inaccuracies that are unacceptable whenever precise position control is important. Time delays are another potential source for significant errors whenever determination of position is important at high rates of angular velocity. This paper presents an analysis of a method of accurately measuring a reference position, or index, at high engine RPMs. These conditions are generally necessary in instrumentation for evaluation or control of magnetic sensors used in ignition timing for the purpose of minimizing exhaust emissions.Details are provided describing the construction and operation of a measurement system to enable convenient determination of angle position with an error of ±0.01° at circumferential surface speeds of up to 37.5 m/s. This dynamic error is equivalent to the static error in a 15-bit encoder. A detailed error analysis is included.