CN102998482A - Measuring method for errors of rotating speed sensor - Google Patents

Abstract

The invention provides a method for measuring the error of a rotation speed sensor, which includes step 1, measuring the sensor delay time T1 and step 2, measuring the transmission delay time T2. In step 1, measure the total number of rising edges and falling edges of phase A and B between the falling edge of the Z-phase single pulse signal corresponding to different speeds and the falling edge of the first crankshaft tooth signal, and calculate the speed sensor at One or more intermediate test speeds and the sensor delay time T1 corresponding to the highest test speed. In step 2, the signal is collected from the signal output end of the rotational speed sensor 3 and the crankshaft signal input end of the engine CPU, and the transmission delay of the signal is judged according to the time difference between the two collected signals. The invention is used for the measurement of the error of the rotational speed sensor.

Description

Measuring Method of Speed Sensor Error

technical field

The invention relates to a method for measuring sensor errors, in particular to a method for measuring errors of rotational speed sensors.

Background technique

The crankshaft sensor (that is, the speed sensor in this article) is one of the most important sensors in the engine electronic control system, which is used to detect the top dead center of the piston, the crank angle and the engine speed, and provide the fuel injection timing to the ECU. Accurate fuel injection timing has a significant impact on engine fuel economy and emissions. With the further deepening of the development and application of the electronic control common rail system, the requirements for the accuracy of the crankshaft signal are also increasing. This requires the crankshaft sensor to provide accurate crankshaft position. Chinese patent CN10716929A discloses a target wheel position detection system, which provides technology for accurately learning the tooth pitch of the tooth theory, allowing the system to accurately calculate position information for small intervals, and compensate for manufacturing tolerances, changes between parts, gear sensors and gear sensors The error caused by system changes, but the fixed delay error generated by the gear sensor itself and the entire signal transmission system cannot be measured, resulting in an error between the actual position of the gear and the output signal of the sensor.

Contents of the invention

The invention provides a method for measuring the error of the speed sensor, which can accurately measure the error of the speed sensor itself (sensor delay), and the error between the actual position of the gear and the signal of the speed sensor caused by the signal delay caused by the signal processing of the engine wiring harness and hardware circuit (transmission Delay). The technical scheme adopted in the present invention is:

A method for measuring an error of a rotational speed sensor, comprising the following two steps:

Step 1: Measurement of sensor delay time T1;

Described step one comprises:

Step 101, use the driving device to drive the crankshaft toothed plate to rotate to reach the initial test speed, and read the distance between the falling edge of the Z-phase single pulse signal corresponding to the initial test speed and the falling edge of the first crankshaft tooth signal on the test PC. The total number of rising edges and falling edges of the two phases A and B; repeat the measurement multiple times and take the average value;

Step 102, use the driving device to drive the crankshaft gear to rotate, gradually increase the test speed, and at one or more intermediate test speeds between the initial test speed and the highest test speed, read the Z corresponding to the middle test speed on the test PC. The total number of rising edges and falling edges of A and B phases between the falling edge of the phase single pulse signal and the falling edge of the first crankshaft tooth signal; repeat the measurement at each intermediate test speed, and take the average value;

Step 103, use the driving device to drive the crankshaft gear to rotate to reach the highest test speed, and read the A, A, B The total number of rising edges and falling edges of the two phases; multiple repeated measurements, taking the average;

Step 104, according to the total edge of the rising edge and falling edge of the two phases A and B between the falling edge of the Z-phase single pulse signal corresponding to the above-mentioned measured intermediate test speed or the highest test speed to the falling edge of the first crankshaft tooth signal number, and the total number of rising edges and falling edges of A and B phases between the falling edge of the Z-phase single pulse signal corresponding to the initial test speed and the falling edge of the first crankshaft tooth signal, and calculate the speed sensor at One or more intermediate test speeds and the sensor delay time T1 corresponding to the highest test speed;

Step 2, measurement of transmission delay time T2;

The second step includes:

Step 201, collect signals from the signal output end of the speed sensor and the CPU crankshaft signal input end of the engine respectively, and judge the transmission delay of the signal according to the time difference between the two signals collected;

Step 202, adjust the rotation speed of the crankshaft toothed plate, repeat step 201, measure the time difference between the signal output terminal of the rotation speed sensor and the crankshaft signal input terminal of the CPU of the engine. The time difference between the signal output terminal of the rotational speed sensor and the signal input terminal of the CPU crankshaft of the engine is consistent in multiple measurements, which is the transmission delay time T2.

Further, in the step one, the test PC is installed with NI DAQ measurement software, and the NI DAQ measurement software is used to complete the A and B phases between the falling edge of the Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal. A measurement of the total number of edges for both rising and falling edges.

The advantages of the present invention: the present invention can accurately measure the error of the rotational speed sensor at different rotational speeds, and then can make up for the error caused by the rotational speed sensor system in practical applications, thereby determining the accurate fuel injection time, so that the fuel in the cylinder can be fully burned, and the It saves fuel and can reduce the tail gas pollution emitted by vehicles.

Description of drawings

Fig. 1 is the schematic diagram of installation of crankshaft toothed disc, encoder and rotational speed sensor of the present invention.

Fig. 2 is the crankshaft tooth signal of the present invention and the Z, A, B phase signal figure of encoder.

Fig. 3 is a diagram of the edge measurement method of the DAQ pulse in the present invention.

Fig. 4 is a schematic diagram of the NOR processing of the pulse signals of A and B phases in the present invention.

Fig. 5 is a distribution diagram of the total number of rising edges and falling edges of A and B phases at different speeds in the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific drawings and embodiments.

A method for measuring the error of a speed sensor. Before the measurement, a speed sensor error measurement system needs to be installed, including installing a crankshaft gear plate 1, an encoder 2, a speed sensor 3, an acquisition card, and a test PC; the speed sensor 3 and the crankshaft gear The position of disc 1 is fixed; the encoder 2 is coaxially connected with the crankshaft disc 1; the acquisition card is installed on the test PC;

Phase A and phase B of encoder 2 output pulse signals of the same fixed number (3600 in this example) per revolution, and phase Z outputs a single pulse signal per revolution; the pulse signal of phase Z of encoder 2 is output to the acquisition card every The AUX terminal of each counter; the A and B phase pulse signals of the encoder 2 are processed by the same OR to generate the same or post pulse signal of A and B, and output to the SOURCE terminal of each counter on the acquisition card; the output of the speed sensor 3 The crankshaft tooth signal is output to the GATE end of each counter on the acquisition card.

A method for measuring an error of a rotational speed sensor, comprising the following two steps:

Step 1: Measurement of sensor delay time T1;

Described step one comprises:

Step 101, use the driving device to drive the crankshaft gear plate 1 to rotate to reach the initial test speed, and read the period between the falling edge of the Z-phase single pulse signal corresponding to the initial test speed and the falling edge of the first crankshaft tooth signal on the test PC The total number of rising edges and falling edges of the two phases A and B of A and B; repeat the measurement multiple times, and take the average value;

Step 102, use the driving device to drive the crankshaft toothed plate 1 to rotate, gradually increase the test speed, at one or more intermediate test speeds between the initial test speed and the highest test speed, read the corresponding value of the middle test speed on the test PC. The total number of rising edges and falling edges of A and B phases between the falling edge of the Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal; repeat the measurement several times at each intermediate test speed, and take average value;

Step 103, use the driving device to drive the crankshaft gear plate 1 to rotate to reach the highest test speed, and read the A between the falling edge of the Z-phase single pulse signal corresponding to the highest test speed and the falling edge of the first crankshaft tooth signal on the test PC. , The total number of rising edges and falling edges of the two phases of B; repeat the measurement multiple times, and take the average value;

Step 104, according to the total edge of the rising edge and falling edge of the two phases A and B between the falling edge of the Z-phase single pulse signal corresponding to the above-mentioned measured intermediate test speed or the highest test speed to the falling edge of the first crankshaft tooth signal number, and the total number of rising edges and falling edges of A and B phases between the falling edge of the Z-phase single pulse signal corresponding to the initial test speed and the falling edge of the first crankshaft tooth signal, and calculate the speed sensor 3 The corresponding sensor delay time T1 at one or more intermediate test speeds and the highest test speed;

Step 2, measurement of transmission delay time T2;

The second step includes:

Step 201, collect signals from the signal output end of the rotational speed sensor 3 and the CPU crankshaft signal input end of the engine respectively, and judge the transmission delay of the signal according to the time difference between the two signals collected;

Step 202, adjust the rotating speed of the crankshaft gear plate 1, repeat step 201, measure the time difference between the signal output end of the rotational speed sensor 3 and the two signals of the CPU crankshaft signal input end of the engine; the signal output end of the rotational speed sensor 3 and the CPU crankshaft of the engine The time difference between the two signals at the signal input end is consistent in multiple measurements, which is the transmission delay time T2.

Further, in the step one, the test PC is installed with NI DAQ measurement software, and the NI DAQ measurement software is used to complete the A and B phases between the falling edge of the Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal. A measurement of the total number of edges for both rising and falling edges.

Below are the detailed instructions.

As shown in FIG. 1 , the rotational speed sensor error measurement system includes a crankshaft gear 1 , an encoder 2 and a rotational speed sensor 3 .

The measurement system uses a DC brushless motor to drive the crankshaft gear 1 to rotate, providing a speed of 0~1500r/min.

The rotational speed sensor 3 is fixed at a certain distance from the outer circumference of the crankshaft toothed disc 1, and measures the magnetic field change caused by the rotating teeth on the crankshaft toothed disc 1, and generates a crankshaft tooth signal (the following crankshaft tooth signal is the output signal of the rotational speed sensor 3) . The rotational speed sensor 3 can be a Hall effect gear sensor, which uses a magnetically biased Hall IC to accurately measure the movement or rotation of the ferrous metal.

Encoder 2 adopts Omron E6HZ-CWZ6C rotary encoder, which is coaxially connected with crankshaft gear 1, and can provide A, B, Z three-phase pulse signals, as shown in Figure 2. Phase A and Phase B output 3600 pulse signals per revolution, with a phase difference of 90°, and Phase Z outputs a single pulse signal per revolution. After the encoder 2 is installed, the single pulse signal of the Z phase corresponds to a certain position of the crankshaft gear plate 1 fixedly.

As shown in Figure 2, the pulse number of phase A is calculated from the falling edge of the Z-phase single pulse signal per revolution of the encoder 2 until the falling edge of the first crankshaft tooth signal, and the trigger signal (Z From the falling edge of the phase single pulse signal) to the falling edge of the first crankshaft tooth signal, the change of the pulse number of phase A is used to analyze the output signal edge of the speed sensor 3 (the falling edge of the first crankshaft tooth signal can be used as an example ) changes. The A phase or B phase of the encoder 2 is 3600 pulse outputs per revolution, so if only the number of one edge (rising edge or falling edge) of the A phase or B phase pulse is counted, the measurement accuracy is 0.1°. In order to improve the measurement accuracy, this paper calculates the total number of rising edges and falling edges of the A and B phases between the falling edge of the Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal, and the measurement accuracy is increased to 0.025° .

The speed sensor error measurement system also includes an acquisition card, a test PC, and the test PC is installed with the LabVIEW software platform of National Instruments (NI) and the NI DAQ measurement software. Acquisition card chooses the PCI-6221 board card of NI Company and installs it on the test PC.

As shown in FIG. 3 , the acquisition card includes two counters, and each counter includes an AUX terminal, a GATE terminal, and a SOURCE terminal. If the AUX terminal of the counter is connected to the first pulse signal, the GATE terminal is connected to the second pulse signal, and the SOURCE terminal is connected to the counting clock signal, the NI DAQ measurement software provides a measurement function that can measure a certain edge of the first pulse signal (rising edge or falling edge) the number of pulses (or the number of edges of the pulse) of the counting clock signal between the first adjacent same edge of the second pulse signal.

Since the PCI-6221 board has only two counters, it cannot count the four edges (rising edge, falling edge of A phase, rising edge, falling edge of B phase) at the same time. If two boards are used, there may be a synchronization problem, so In this paper, the pulse square waves of A and B phases are processed together or, as shown in Figure 4. After the pulse signals of A and B phases are processed with the same or, the total number of rising and falling edges of the same or subsequent pulse signals of A and B generated is equal to the total number of rising and falling edges of the two phases of A and B.

In this embodiment, the AUX terminal of each counter is connected to the Z-phase pulse signal of the encoder 2, the GATE terminal is connected to the crankshaft tooth signal output by the speed sensor 3, and the SOURCE terminal is connected to the A and B of the encoder 2. Pulse signal. From the falling edge of the Z-phase monopulse signal to the falling edge of the first crankshaft tooth signal (referred to as the measurement cycle), use the two counters of the PCI-6221 board to measure the same or subsequent pulse signals of A and B at the same time. The number of rising edges and falling edges is added to get the total number of rising and falling edges of A and B phases from the falling edge of the Z-phase single pulse signal to the falling edge of the first crankshaft tooth signal.

The measurement process of the rotational speed sensor error is described in detail below.

If the real position of the tooth edge of the crankshaft disc 1 is measured, it is necessary to ensure that the tooth position of the tooth disc measured at different speeds is consistent with the actual position of the tooth edge. The difficulty lies in the measurement of the true position of the tooth edge. The speed of the gear plate is high, the measurement space is small, and the measurement accuracy is high. Considering that it is difficult and costly to measure the absolute tooth edge position at high speed, this paper adopts the measurement of relative position.

The measurement of the speed sensor error consists of two steps.

Step 1, measuring the delay time T1 of the sensor. As shown in Figure 5, this paper calculates the total number of rising and falling edges of A and B phases between the trigger signal (the falling edge of the Z-phase single pulse signal) and the falling edge of the first crankshaft tooth signal at different speeds. To collect, in order to eliminate the measurement error of the Hall sensor itself, the test is carried out in a constant temperature environment, and the distance between the speed sensor 3 and the crankshaft gear 1 is fixed. The initial test speed of the crankshaft toothed disc 1 is relatively low, in this example at 20r/min, the delay of the speed sensor 3 at the initial test speed is very small and can be ignored. Gradually increase the speed, the crankshaft toothed plate 1 is constantly rotating, when the tooth edge arrives, it will cause a change in magnetic flux, the speed sensor 3 needs to capture the change of the magnetic flux and then amplify the signal, and during this time, the crankshaft toothed plate 1 is still rotating, the higher the speed, the greater the angle difference between the signal and the actual tooth edge, and the A and B two-phase rises between the falling edge of the collected Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal The total number of edges and falling edges will also increase. In this example, in order to improve the measurement accuracy, what is actually collected is the total number of edges from the falling edge of the Z-phase single pulse signal to the falling edge of the first crankshaft tooth signal, and the rising and falling edges of the two phases A and B. The initial test speed of the test in this example is 20r/min, and the total edge of the rising and falling edges of the two phases A and B between the falling edge of the Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal is measured The number is 52 (in order to be more accurate, the measurement is repeated many times, and the average value is taken). Gradually increase the test speed, and measure the A and B phases between the falling edge of the Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal at one or more intermediate test speeds until the highest test speed. The total number of rising and falling edges. The highest test speed tested in this example is 1500r/min, and the measured total number of rising and falling edges of A and B phases between the falling edge of the Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal It is 61.5 (in order to be more accurate, repeat the measurement multiple times and take the average value). At the highest test speed, the calculation of the delay time T1 of the speed sensor 3: the maximum test speed of the crankshaft gear plate 1 is 1500 rpm or 25 rpm, and according to the A phase or B phase is sent 3600 pulses / revolution, then the calculation Phase A or phase B can send out 3600*25=90000 pulses per second, and each pulse period of phase A or phase B corresponds to 4 edges (rising edge plus falling edge) of the same or subsequent pulse signal of A and B. That is, 90000*4=360000 edges of the same or post-pulse signal of A and B per second. Then the delay time T1 of the speed sensor 3 at the highest test speed is T1=(61.5-52)*(1/360000)≈26.4us. Similarly, the delay time T1 of the sensor 3 corresponding to each intermediate test rotational speed can also be calculated.

In summary, Step 1 includes the following sub-steps:

Step 101, use the driving device to drive the crankshaft gear plate 1 to rotate to reach the initial test speed, and read the period between the falling edge of the Z-phase single pulse signal corresponding to the initial test speed and the falling edge of the first crankshaft tooth signal on the test PC The total number of rising edges and falling edges of the two phases A and B of A and B; repeat the measurement multiple times, and take the average value;

Step 102, use the driving device to drive the crankshaft toothed plate 1 to rotate, gradually increase the test speed, at one or more intermediate test speeds between the initial test speed and the highest test speed, read the corresponding value of the middle test speed on the test PC. The total number of rising edges and falling edges of A and B phases between the falling edge of the Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal; repeat the measurement several times at each intermediate test speed, and take average value;

Step 103, use the driving device to drive the crankshaft gear plate 1 to rotate to reach the highest test speed, and read the A between the falling edge of the Z-phase single pulse signal corresponding to the highest test speed and the falling edge of the first crankshaft tooth signal on the test PC. , The total number of rising edges and falling edges of the two phases of B; repeat the measurement multiple times, and take the average value;

Step 104, according to the total edge of the rising edge and falling edge of the two phases A and B between the falling edge of the Z-phase single pulse signal corresponding to the above-mentioned measured intermediate test speed or the highest test speed to the falling edge of the first crankshaft tooth signal number, and the total number of rising edges and falling edges of A and B phases between the falling edge of the Z-phase single pulse signal corresponding to the initial test speed and the falling edge of the first crankshaft tooth signal, and calculate the speed sensor 3 The corresponding sensor delay time T1 at one or more intermediate test speeds and the highest test speed;

Step 2, measurement of the transmission delay time T2. This step requires several measurements on the car engine. The transmission of the Hall sensor signal is first through the engine line speed, the ECU (Electronic Control Unit of the engine) line speed, and then through the ECU hardware filtering, and then enters the CPU of the engine for calculation and processing. Since the crankshaft is still rotating at a high speed during signal transmission, there is a hardware delay time between the gear signal sent by the speed sensor 3 and the signal being collected by the CPU, so that the CPU captures the tooth position of the crankshaft 1 and the actual position of the crankshaft 1. The deviation of the tooth position will affect the calculation of the fuel injection advance angle. The test results show that the transmission delay time of the speed sensor 3 is consistent at different speeds of the crankshaft gear plate 1;

Step 2 mainly includes:

Step 201, collect signals from the signal output end of the rotational speed sensor 3 and the CPU crankshaft signal input end of the engine respectively, and judge the transmission delay of the signal according to the time difference between the two signals collected;

Step 202, adjust the rotating speed of the crankshaft gear plate 1, repeat step 201, measure the time difference between the signal output end of the rotational speed sensor 3 and the two signals of the CPU crankshaft signal input end of the engine; the signal output end of the rotational speed sensor 3 and the CPU crankshaft of the engine The time difference between the two signals at the signal input end is consistent in multiple measurements, which is the transmission delay time T2.

The test results show that the transmission delay time of the rotational speed sensor 3 at different rotational speeds of the crankshaft gear plate 1 is consistent, which is the transmission delay time T2.

The speed sensor error is equal to the sum of the sensor delay time T1 and the transmission delay time T2.

Claims (2)

1. A measuring method of rotational speed sensor error is characterized in that, comprises following two major steps: Step 1: Measurement of sensor delay time T1; Described step one comprises: Step 101, use the driving device to drive the crankshaft gear plate (1) to rotate to reach the initial test speed, and read the falling edge of the Z-phase single pulse signal corresponding to the initial test speed to the falling edge of the first crankshaft tooth signal on the test PC The total number of edges between the rising and falling edges of A and B phases; repeat the measurement multiple times and take the average; Step 102, use the driving device to drive the crankshaft toothed plate (1) to rotate, gradually increase the test speed, and read out the middle test speed on the test PC at one or more intermediate test speeds between the initial test speed and the highest test speed The total number of rising edges and falling edges of A and B phases between the falling edge of the corresponding Z-phase single pulse signal and the falling edge of the first crankshaft tooth signal; repeat the measurement several times at each intermediate test speed ,take the average; Step 103, use the drive equipment to drive the crankshaft gear plate (1) to rotate to reach the highest test speed, and read the period between the falling edge of the Z-phase single pulse signal corresponding to the highest test speed and the falling edge of the first crankshaft tooth signal on the test PC The total number of rising edges and falling edges of the two phases A and B of A and B; repeat the measurement multiple times, and take the average value; Step 104, according to the total edge of the rising edge and falling edge of the two phases A and B between the falling edge of the Z-phase single pulse signal corresponding to the above-mentioned measured intermediate test speed or the highest test speed to the falling edge of the first crankshaft tooth signal number, and the total number of rising edges and falling edges of A and B phases between the falling edge of the Z-phase single pulse signal corresponding to the initial test speed and the falling edge of the first crankshaft tooth signal, and calculate the speed sensor ( 3) The sensor delay time T1 corresponding to one or more intermediate test speeds and the highest test speed; Step 2, measurement of transmission delay time T2; The second step includes: Step 201, collect signals from the signal output end of the rotational speed sensor (3) and the CPU crankshaft signal input end of the engine respectively, and judge the transmission delay of the signal according to the time difference of the two signals collected; Step 202, adjust the rotating speed of the crankshaft toothed disc (1), repeat step 201, measure the time difference of the two signals of the signal output terminal of the rotational speed sensor (3) and the two signals of the CPU crankshaft signal input end of the engine; the signal output of the rotational speed sensor (3) The time difference between the two signals at the terminal and the engine's CPU crankshaft signal input terminal is consistent in multiple measurements, which is the transmission delay time T2. 2. the measuring method of rotational speed sensor error as claimed in claim 1 is characterized in that: in described step 1, test PC machine installs NI DAQ measurement software, uses NI DAQ measurement software to complete the falling edge of Z-phase monopulse signal to The measurement of the total number of rising edges and falling edges of A and B phases between the falling edges of the first crankshaft tooth signal.

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