摘要:
A position detector for controlling an object to be controlled, e.g. a motor, which measures the output from a sensor for detecting the position of the object when a specified time elapses after detecting a positional data output request signal and calculates a positional data representative of the position of the object at the moment of time when a measurement is performed based on the measured output. Receiving interval of the request signal is also measured and a corrected positional data representative of the position of the object at the time of receiving the request signal during measurement of the receiving interval is calculated using a value obtained by subtracting the specified time from a measured receiving interval, a calculated positional data, and an estimated variation rate of the position of the object. The corrected positional data is outputted as a response to the request signal.
摘要:
A position sensor for measuring an absolute position by A/D-converting sine and cosine wave signals and by performing interpolation, wherein the phase error between both signals caused by the movement of an object to be measured during the A/D conversion is corrected, and as a result the sample-and-hold circuit conventionally required to maintain the simultaneity of an analog signal can be omitted, thereby lowering the cost and reducing the size. A position sensor of high-resolution type can have the advantages. Position data before the previous request is stored in an RAM (12). According to the position data, a CPU (10) predicts the phase shift of one signal caused by the movement during the A/D conversion of the other signal, and position data is calculated by correcting the predicted phase shift.
摘要:
An absolute value encoder for sensing the number of revolutions, wherein an A-phase/B-phase generating section (610) generates A-phase/B-phase one-period pulse signals the phases of which are 90 degrees different from each other within one revolution of the shaft on the basis of the light passing through a slit rotating together with the shaft. When an A-phase/B-phase status sensing section (640) senses a change of the pulse signals, a clock generating section (66) switches the clock frequency.
摘要:
A length measuring instrument is provided with a light emitting section which emits a laser beam having a frequency f, an interference system which generates and emits a reference beam having a frequency f+f1 in a straight line and a detection beam having a frequency f+f2 at a prescribed inclination angle upon receiving the laser beam, a movement detecting section which reflects the reference and detection beams toward the interference system, a light receiving section which converts a reference interference wave generated by the interference system into a first sine-wave electric signal and a detection interference wave produced by the difference in optical path length between the reflected reference and detection beams into a second sine-wave electric signal, a signal processing section which respectively generates first and second cosine-wave signals from the first and second sine-wave signals and A/D-converts the four signals, and an arithmetic section which finds the electrical angle of the reference interference wave, the electrical angle of the detection interference wave and the phase difference between the reference and detection interference waves from the two electrical angles, and determines the position of the moving detecting section based on the phase difference and the wavelength of the laser beam.