High-precision adaptive device for motor rotation speed measurement

Abstract

The invention discloses a high-precision adaptive device for motor rotation speed measurement. The high-precision adaptive device at least comprises a crystal oscillator, an encoder signal conditioning circuit, a FPGA (Field Programmable Gate Array) chip and a microprocessor circuit, wherein the FPGA chip at least comprises a reset pulse Z-period measurement circuit, a self-adaptive speed measurement circuit and a register block. The reset pulse Z-period measurement circuit is composed of a delay circuit, a clock divider, a counter and a time-to-digital converter and realizes high-precision motor rotation speed measurement. The self-adaptive speed measurement circuit is composed of a period estimation circuit, a self-adaptive period valve generation circuit, a self-adaptive period measurement circuit and a complementing circuit and realizes the self-adaptive motor rotation speed measurement. Due to the adoption of the high-precision adaptive device, the influence of mechanical errors of an encoder on the accuracy of motor rotation speed measurement can be eliminated, so that the accuracy of motor rotation speed measurement is not limited to a counting clock, the measurement period can be self-adaptively changed according to the different rotation speeds of a motor, the measurement response time of the low rotation speed of the motor is shortened, and the measurement accuracy of medium and high rotation speeds is increased.

Description

technical field [0001] The invention relates to the technical field of motor speed measurement, in particular to a high-precision self-adaptive device for motor speed measurement of a motor equipped with an incremental photoelectric encoder. Background technique [0002] In many fields such as industrial automation, aviation, automobiles, precision CNC machine tools, machining centers, navigation systems, robots, etc., photoelectric encoders are usually used to measure the motor speed to realize closed-loop and semi-closed-loop control of the system. At present, the devices that process the photoelectric encoder signal to realize the motor speed measurement include: general counter chip, special photoelectric encoding signal processing chip, digital signal processor (DSP) and FPGA and other devices. Using general-purpose counter chips (such as uPD4702 and uPD4704 of NEC Company) and special photoelectric coding signal processing chips (such as HCTL2032 of Agilent Company) to...

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Problems solved by technology

Using general-purpose counter chips (such as uPD4702 and uPD4704 of NEC Company) and special photoelectric coding signal processing chips (such as HCTL2032 of Agilent Company) to realize motor speed measurement has low precision, slow processing speed, requires a large number of peripheral devices, and complex circuit structure , low reliability, etc.

Using a dedicated DSP with an orthogonal decoding module (such as TMS320F2812 from TI) and an FPGA device has a fast processing speed, but the measurement methods are limited to the T method, M method, and MT method to achieve motor speed measurement, and the MT method is within the entire speed range. All have good accuracy, but at low speeds, it takes a long detection time to ensure the accuracy, which cannot meet the requirements of fast dynamic response of the speed detection system, and the detection accuracy of the device using the above three methods is usually affected by the mechanical manufacturing error of the encoder Affected, or limited by the clock frequency of the counting clock, and the measurement period cannot be adaptively changed according to different rotational speeds

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