| 摘要 |
PURPOSE:To conduct detection of speed in a low range with high sensitivity and low noises by inputting sine waves to a resolver, the phases of which are mutually off by 90 deg. and obtaining and differentiating the phase information according to the rotational angle. CONSTITUTION:Sine waves (angular frequency: omega) with phase difference of 90 deg. between them are supplied respectively to the exciting coils Walpha and Wbeta of a resolver 1. The output of a detection coil WD becomes a sine wave but its signal phase corresponds to the rotational angle thetae of the detection coil. This detection signal and one of exciting signals are multiplied by a multiplier 3 to obtain a signal that contains two frequency components omega and dthetae/dt. If this signal is freed of high frequency component omega through a low pass filter 4, it becomes a signal that is proportional to costhetae. If it is differentiated, its amplitude is proportional to dthetae/dt, that is, it represents angular speed. When the signal is passed through an absolute value circuit 6 and a smoothing circuit 7, direct current voltage can be obtained that is proportional to the speed. |
