摘要 |
A velocity servo for a motor wherein a high speed tachometer is replaced by an arrangement which mathematically converts the input voltage and current to the motor into a speed signal, utilizing known formulas and constants. To maintain accuracy of the servo when the constants change value with the temperature, an inexpensive low speed tachometer is utilized to derive a signal indicative of the actual speed of the motor and this speed signal is compared with the mathematically computed speed signal. In the event that there is a difference, the constants are modified in accordance with such difference. This can be implemented either by electrically alterable circuit values or through computer or microprocessor techniques. |