CN107449376A - A kind of steering wheel angle acquisition system in real time - Google Patents

Abstract

The invention is applicable to the technical field of automobile simulation experiments, and provides a real-time steering wheel angle acquisition system. The rotation angle signal collector of the present invention generates a pulse signal according to the rotation of the steering wheel steering rod, and sends the generated pulse signal to the rotation angle signal processor, and the rotation angle signal processor counts according to the received pulse signal, and calculates according to the counting result The corresponding steering wheel angle is sent to the terminal device, and the terminal device generates the rotation angle data of the steering wheel according to the counting result and the pre-stored calculation formula. Compared with the prior art, the system of the present invention is easy to install and has no influence on the mechanical structure of the vehicle. At the same time, the signal collected by the system is consistent with other electronic control signals of the vehicle, and there will be no discrepancy, and the signal collection has high accuracy and fast speed.

Description

A real-time steering wheel angle acquisition system

technical field

The invention belongs to the technical field of automobile simulation experiments, in particular to a real-time steering wheel angle acquisition system.

Background technique

In the car simulation test, the measurement of the steering wheel rotation angle usually requires the use of a steering wheel angle sensor, which is mostly installed in the steering column under the steering wheel, and is divided into two types: analog steering wheel angle sensor and digital steering wheel angle sensor. The commonly used steering wheel angle sensor uses a mechanical structure of three gears to measure the angle of rotation and the number of turns. The large gear rotates together with the steering wheel column, and the two small gears have a difference of 1 tooth, which is fixed on the vehicle body together with the sensor housing and does not rotate with the steering wheel. The two pinions respectively collect the angle of rotation that rotates with the steering wheel. Due to the difference of one tooth, different turns will have a specific angle difference, and the absolute angle of rotation of the steering wheel can be obtained through calculation. This method is not only complex in mechanical structure and slow in speed and poor in real-time performance, it cannot achieve the effect of online real-time display of the corner value, and the accuracy is not high, which affects the evaluation of vehicle performance.

Contents of the invention

The technical problem to be solved by the embodiments of the present invention is to provide a real-time steering wheel angle acquisition system, which aims to solve the problems of complicated installation, low measurement accuracy and poor real-time performance of the steering wheel angle sensor in the prior art.

The first aspect of the embodiment of the present invention provides a real-time steering wheel angle acquisition system, the system comprising:

Corner signal collector, corner signal processor and terminal equipment;

The corner signal processor is respectively connected to the corner signal collector and the terminal device;

The rotation angle signal collector is configured to generate a pulse signal according to the rotation of the steering wheel steering rod, and send the generated pulse signal to the rotation angle signal processor;

The corner signal processor is configured to perform counting according to the received pulse signal, and send the counting result to the terminal device;

The terminal device is configured to generate the rotation angle data of the steering wheel according to the counting result and a pre-stored calculation formula.

Further, the rotation angle signal collector is specifically a fixed incremental photoelectric encoder;

The fixed incremental photoelectric encoder is coaxially connected to the steering wheel steering rod, and the zero point position of the fixed incremental photoelectric encoder coincides with the zero point position of the steering wheel;

When the steering rod rotates, the fixed incremental photoelectric encoder generates A and B phase pulse signals with a phase difference of 90°, and outputs them to the rotation angle signal processor;

When the steering rod rotates clockwise, the A-phase pulse signal leads the B-phase pulse signal by 90°, and when the steering rod rotates counterclockwise, the B-phase pulse signal leads the A-phase pulse signal by 90°;

When the steering rod passes the zero position of the fixed incremental photoelectric encoder, the fixed incremental photoelectric encoder generates a high-level Z-phase pulse signal.

Further, the corner signal processor includes:

A sixteen-bit counter composed of four series-connected four-bit counters, and four series-connected synchronous holders;

Four of the four-bit counters include:

The first 40193 chip, the second 40193 chip, the third 40193 chip, and the fourth 40193 chip;

The four Sync Keepers include:

The first 74LS175 chip, the second 74LS175 chip, the third 74LS175 chip, and the fourth 74LS175 chip;

The first 40193 chip is connected to the first 74LS175 chip, the second 40193 chip is connected to the second 74LS175 chip, the third 40193 chip is connected to the third 74LS175 chip, and the fourth 40193 chip is connected to the second 74LS175 chip. The chip is connected with the fourth 74LS175 chip.

Further, the corner signal processor also includes:

phase detector;

The A-phase pulse output port of the fixed incremental photoelectric encoder is connected to the 5th pin of the first 40193 chip through the phase detector, and the B-phase pulse output port of the fixed incremental photoelectric encoder connected to the 4th pin of the first 40193 chip through the phase detector;

When the received A-phase pulse signal leads the B-phase pulse signal by 90°, the sixteen-bit counter counts up, and when the received B-phase pulse signal leads the A-phase pulse signal by 90°, the sixteen-bit counter counts down count.

Further, the 12th pin of the first 40193 chip is connected to the 5th pin of the second 40193 chip, the 13th pin of the first 40193 chip is connected to the 4th pin of the second 40193 chip foot connection;

The 12th pin of the second 40193 chip is connected to the 5th pin of the third 40193 chip, and the 13th pin of the second 40193 chip is connected to the 4th pin of the third 40193 chip;

The 12th pin of the third 40193 chip is connected to the 5th pin of the fourth 40193 chip, and the 13th pin of the third 40193 chip is connected to the 4th pin of the fourth 40193 chip;

The 2nd, 3rd, 6th, 7th pins of the first 40193 chip are respectively connected with the 4th, 5th, 12th, 13th pins of the first 74LS175 chip;

The 2nd, 3rd, 6th, and 7th pins of the second 40193 chip are respectively connected to the 4th, 5th, 12th, and 13th pins of the second 74LS175 chip;

The 2nd, 3rd, 6th, and 7th pins of the third 40193 chip are respectively connected to the 4th, 5th, 12th, and 13th pins of the third 74LS175 chip;

The 2nd, 3rd, 6th and 7th pins of the fourth 40193 chip are respectively connected with the 4th, 5th, 12th and 13th pins of the fourth 74LS175 chip.

Further, the phase detector is composed of a D flip-flop, a first NAND gate, and a second NAND gate;

The A-phase pulse output port of the fixed incremental photoelectric encoder is respectively connected to the CLK input end of the D flip-flop, the first input end of the first NAND gate, and the first input end of the second NAND gate. The input terminal is connected, the B-phase pulse output port of the fixed incremental photoelectric encoder is connected with the D input terminal of the D flip-flop, and the D flip-flop The output terminal is connected to the second input terminal of the first NAND gate, the Q output terminal of the D flip-flop is connected to the second input terminal of the second NAND gate, and the output of the first NAND gate terminal is connected with the 5th pin of the first 40193 chip, and the output terminal of the second NAND gate is connected with the 4th pin of the first 40193 chip;

When the received A-phase pulse signal is ahead of the B-phase pulse signal by 90°, the D flip-flop The output terminal outputs a high-level signal, the Q output terminal of the D flip-flop outputs a low-level signal, the first NAND gate is opened, the second NAND gate is closed, and the sixteen-bit counter counts up;

When the received B-phase pulse signal is ahead of the A-phase pulse signal by 90°, the D flip-flop The output terminal outputs a low level signal, the Q output terminal of the D flip-flop outputs a high level signal, the first NAND gate is closed, the second NAND gate is opened, and the sixteen-bit counter counts down.

Further, the corner signal processor also includes:

inverter;

The Z-phase pulse output port of the fixed incremental photoelectric encoder is respectively connected with the 11th pin of the first 40193 chip and the 11th pin of the second 40193 chip through an inverter;

The inverter is used to convert the high-level Z-phase pulse signal into a low-level Z-phase pulse signal;

The low-level Z-phase pulse signal is used to count the count values of the first 40193 chip and the second 40193 chip when the count values of the third 40193 chip and the fourth 40193 chip are zero to clear.

Further, the corner signal processor also includes:

Power supply voltage, first light-emitting diode, second light-emitting diode, third light-emitting diode, fourth light-emitting diode, fifth light-emitting diode, sixth light-emitting diode, seventh light-emitting diode, eighth light-emitting diode, ninth light-emitting diode, tenth Light-emitting diodes, eleventh light-emitting diodes, twelfth light-emitting diodes, thirteenth light-emitting diodes, fourteenth light-emitting diodes, fifteenth light-emitting diodes, sixteenth light-emitting diodes;

The cathodes of the first light-emitting diode, the second light-emitting diode, the third light-emitting diode, and the fourth light-emitting diode are respectively connected to the 3rd, 6th, 11th, and 14th pins of the first 74LS175 chip, and the anode is connected to the power supply voltage;

The cathodes of the fifth light-emitting diode, the sixth light-emitting diode, the seventh light-emitting diode, and the eighth light-emitting diode are respectively connected to the 3rd, 6th, 11th, and 14th pins of the second 74LS175 chip, and the anode is connected to the power supply voltage;

The cathodes of the ninth light-emitting diode, the tenth light-emitting diode, the eleventh light-emitting diode, and the twelfth light-emitting diode are respectively connected to pins 3, 6, 11, and 14 of the third 74LS175 chip, and the anode is connected to the power supply voltage;

The cathodes of the thirteenth light-emitting diode, the fourteenth light-emitting diode, the fifteenth light-emitting diode, and the sixteenth light-emitting diode are respectively connected to the 3rd, 6th, 11th, and 14th pins of the fourth 74LS175 chip, and the anode is connected to the power supply voltage .

Further, the terminal device is respectively connected to pins 2, 7, 10, and 15 of the first 74LS175 chip, the second 74LS175 chip, the third 74LS175 chip, and the fourth 74LS175 chip;

The terminal device is configured to acquire the counting result, and generate the rotation angle data of the steering wheel according to the preset corresponding relationship between the counting result and the steering wheel rotation angle.

Further, the terminal device includes a data acquisition card for acquiring counting results.

From the above-mentioned embodiments of the present invention, it can be known that the rotation angle signal collector of the present invention generates a pulse signal according to the rotation of the steering wheel steering rod, and sends the generated pulse signal to the rotation angle signal processor, and the rotation angle signal processor performs according to the received pulse signal. Counting, and sending the counting result to the terminal device, the terminal device generates the rotation angle data of the steering wheel according to the counting result and the pre-stored calculation formula. Compared with the prior art, the system of the present invention is simple to install and has no effect on the mechanical structure of the vehicle , At the same time, the signal collected by the system is consistent with other electronic control signals of the whole vehicle, there will be no discrepancy, and the accuracy of signal collection is high and the speed is fast.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings on the premise of not paying creative efforts.

Accompanying drawing 1 is the structural representation of the real-time steering wheel angle acquisition system that the first embodiment of the present invention provides;

Accompanying drawing 2 is the concrete structural representation of the real-time steering wheel angle collection system that the first embodiment of the present invention provides;

Accompanying drawing 3 is the flow chart of clearing the count value of the low counter in the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention;

Accompanying drawing 4 is the working principle diagram of the real-time steering wheel angle acquisition system that the first embodiment of the present invention provides;

Accompanying drawing 5 is the steering wheel angle flow chart corresponding to the steering wheel counting pulse calculation in the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention;

Accompanying drawing 6 is the structural representation of the inverter in the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention;

Accompanying drawing 7 is the structure diagram of the phase detector in the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention;

Accompanying drawing 8 is a pin diagram of the 40193 chip in the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention;

Accompanying drawing 9 is a pin definition diagram of the 40193 chip in the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention;

Accompanying drawing 10 is a functional diagram of the 40193 chip in the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention;

Figure 11 is a phase diagram of the 40193 chip in the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention.

detailed description

In order to make the purpose, features, and advantages of the embodiments of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, The described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts belong to the protection scope of the present invention.

Please refer to accompanying drawing 1, accompanying drawing 1 is the structure diagram of the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention, for the convenience of description, only shows the part related to the embodiment of the present invention. The real-time steering wheel rotation angle acquisition system illustrated in FIG. 1 mainly includes: a rotation angle signal collector 101 , a rotation angle signal processor 102 and a terminal device 103 .

The corner signal processor 102 is connected to the corner signal collector 101 and the terminal device 103 respectively.

The rotation angle signal collector 101 is configured to generate a pulse signal according to the rotation of the steering rod of the steering wheel, and send the generated pulse signal to the rotation angle signal processor 102 .

The corner signal processor 102 is configured to perform counting according to the received pulse signal, and send the counting result to the terminal device 103 .

The terminal device 103 is configured to generate the rotation angle data of the steering wheel according to the counting result and the pre-stored calculation formula.

Please refer to accompanying drawing 2, which is a specific structural diagram of the real-time steering wheel angle acquisition system provided by the first embodiment of the present invention.

The rotation angle signal collector 101 is specifically a fixed incremental photoelectric encoder 201 .

The fixed incremental photoelectric encoder 201 is coaxially fixedly connected with the steering rod of the steering wheel, and the zero point position of the fixed incremental photoelectric encoder 201 coincides with the zero point position of the steering wheel.

When the steering rod rotates, the A and B phases of the fixed incremental photoelectric encoder generate two pulse signals with a phase difference of 90°, and output them to the rotation angle signal processor.

When the steering rod rotates clockwise, the phase A pulse signal is 90° ahead of the phase B pulse signal. When the steering rod rotates counterclockwise, the phase B pulse signal is 90° ahead of the phase A pulse signal. When the steering rod passes through the fixed incremental photoelectric encoder When the zero position of the encoder is reached, the fixed incremental photoelectric encoder generates a high-level Z-phase pulse signal.

Corner signal processor 102 includes:

A sixteen-bit counter composed of four series-connected four-bit counters, and four series-connected sync keepers.

The four four-bit counters include:

The first 40193 chip, the second 40193 chip, the third 40193 chip, and the fourth 40193 chip.

The four synchrokeepers include:

The first 74LS175 chip, the second 74LS175 chip, the third 74LS175 chip, and the fourth 74LS175 chip.

The first 40193 chip is connected to the first 74LS175 chip, the second 40193 chip is connected to the second 74LS175 chip, the third 40193 chip is connected to the third 74LS175 chip, and the fourth 40193 chip is connected to the fourth 74LS175 chip.

The counting method of the 40193 counting chip is binary counting, and four 40193 chips are connected in series to form a 16-bit counter. During the counting process of the counter, each instantaneous count value will have a great change, which requires that the value of the 16-bit counter at the same time should be obtained when obtaining the count value. In order to meet this requirement, the circuit is designed. Four 74LS175D flip-flop ICs are connected in series to maintain the 16-bit value of the instantaneous corner.

The rotation angle signal processor 102 also includes a phase detector 203 . The A-phase pulse output port of the fixed incremental photoelectric encoder 201 is connected to the 5th pin of the first 40193 chip through the phase detector 203, and the B-phase pulse output port of the fixed incremental photoelectric encoder 201 is passed through the phase detector 203 Connect with pin 4 of the first 40193 chip.

When the received A-phase pulse signal is 90° ahead of the B-phase pulse signal, the 16-bit counter counts up, and when the received B-phase pulse signal is 90° ahead of the A-phase pulse signal, the 16-bit counter counts down.

The 12th pin of the first 40193 chip is connected to the 5th pin of the second 40193 chip, and the 13th pin of the first 40193 chip is connected to the 4th pin of the second 40193 chip.

The 12th pin of the second 40193 chip is connected to the 5th pin of the third 40193 chip, and the 13th pin of the second 40193 chip is connected to the 4th pin of the third 40193 chip.

The 12th pin of the third 40193 chip is connected to the 5th pin of the fourth 40193 chip, and the 13th pin of the third 40193 chip is connected to the 4th pin of the fourth 40193 chip.

The 2nd, 3rd, 6th, 7th pins of the first 40193 chip are respectively connected with the 4th, 5th, 12th, 13th pins of the first 74LS175 chip.

The 2nd, 3rd, 6th, 7th pins of the second 40193 chip are respectively connected with the 4th, 5th, 12th, 13th pins of the second 74LS175 chip.

The 2nd, 3rd, 6th, 7th pins of the third 40193 chip are respectively connected with the 4th, 5th, 12th, 13th pins of the third 74LS175 chip.

The 2nd, 3rd, 6th, 7th pins of the fourth 40193 chip are respectively connected with the 4th, 5th, 12th, 13th pins of the fourth 74LS175 chip.

Specifically, the phase detector 203 (as shown in FIG. 7 ) is composed of a D flip-flop G1, a first NAND gate N1, and a second NAND gate N2.

The A-phase pulse output port of the fixed incremental photoelectric encoder is respectively connected to the CLK input terminal of the D flip-flop G1, the first input terminal of the first NAND gate N1, and the first input terminal of the second NAND gate N2. The B-phase pulse output port of the incremental photoelectric encoder is connected to the D input terminal of the D flip-flop G1, and the D flip-flop G1 The output terminal is connected with the second input terminal of the first NAND gate N1, the Q output terminal of the D flip-flop G1 is connected with the second input terminal of the second NAND gate N2, and the output terminal of the first NAND gate N1 is connected with the first NAND gate N1. The 5th pin of the 40193 chip is connected, and the output end of the second NAND gate N2 is connected with the 4th pin of the first 40193 chip.

When the steering wheel is turning forward, the A-phase pulse signal is 90° ahead of the B-phase pulse signal, and the D flip-flop G1 The output terminal outputs a high-level signal, the Q output terminal of the D flip-flop G1 outputs a low-level signal, the first NAND gate N1 is opened, and the counting pulse is sent to the first 40193 chip through the output terminal of the first NAND gate N1 5 pin (the pulse input end of the 16-bit counter) is used for counting up. At this time, the second NAND gate N2 is closed, and its output end outputs a high-level signal.

When the steering wheel is reversed, the B-phase pulse signal is 90° ahead of the A-phase pulse signal, and the D flip-flop G1 The output terminal outputs a low-level signal, the Q output terminal of the D flip-flop G1 outputs a high-level signal, the first NAND gate N1 is closed, and its output terminal outputs a high-level signal. At this time, the second NAND gate N2 is opened. The counting pulse is sent to the 4th pin of the first 40193 chip (the downpulse input terminal of the sixteen-bit counter) through the output end of the second NAND gate N2 to perform subtraction counting.

Corner signal processor 102 also includes:

Inverter 202;

When the steering rod passes the zero position of the fixed incremental photoelectric encoder 201, the fixed incremental photoelectric encoder 201 generates a high-level Z-phase pulse signal.

The inverter 202 is used to convert the high-level Z-phase pulse signal into a low-level Z-phase pulse signal.

The Z-phase pulse output port of the fixed incremental photoelectric encoder 201 is respectively connected to the 11th pin of the first 40193 chip and the 11th pin of the second 40193 chip through the inverter 202 .

The low-level Z-phase pulse signal is used to clear the count values of the first 40193 chip and the second 40193 chip when the count values of the third 40193 chip and the fourth 40193 chip are zero.

Inverter 202 (as shown in Figure 6) includes: resistance R01, resistance R02, resistance RZ, triode D0, light-emitting diode LED, +5V voltage, is used for the high level Z that fixed incremental photoelectric encoder 201 produces The phase pulse signal reverses to a low-level Z-phase pulse signal.

If we do not change lanes when driving normally, the steering wheel will swing around zero for a long time, so the counter accumulates a large number of AB addition and subtraction signals for a long time. These signals are not the effective steering wheel angle signals we expect, and the long-term accumulation will cause The zero position of the steering wheel drifts, which is a fatal mistake in the vehicle dynamics test. Therefore, in order to avoid the accumulation of counting errors, it is necessary to clear the counting of the frequent zero swing of the steering wheel, and this function is used It is realized by the Z-phase pulse signal generated by the photoelectric encoder every 360 degrees. Specifically, because the photoelectric encoder generates a high-level Z-phase pulse signal at the beginning, and the number terminal of the 40193 counting chip is low-bit effective , so an inverter is needed to invert the high-level Z-phase pulse signal generated by the photoelectric encoder into a low-level input to the No. 11 digital terminal of the 40193 chip.

Corner signal processor 102 also includes:

Power supply voltage V, first LED D1, second LED D2, third LED D3, fourth LED D4, fifth LED D5, sixth LED D6, seventh LED D7, eighth LED D8, ninth LED D9, tenth LED D10, eleventh LED D11, twelfth LED D12, thirteenth LED D13, fourteenth LED D14, fifteenth LED D15, Sixteen LEDs D16.

The cathodes of the first light-emitting diode D1, the second light-emitting diode D2, the third light-emitting diode D3, and the fourth light-emitting diode D4 are respectively connected to the 3rd, 6th, 11th, and 14th leads of the first 74LS175 chip through resistors R1, R2, R3, and R4. The pin is connected, and the anode is connected to the power supply voltage through diodes D18 and D17.

The cathodes of the fifth light-emitting diode D5, the sixth light-emitting diode D6, the seventh light-emitting diode D7, and the eighth light-emitting diode D8 are respectively connected to the 3rd, 6th, 11th, and 14th leads of the second 74LS175 chip through resistors R5, R6, R7, and R8. The pin is connected, and the anode is connected to the power supply voltage through diodes D18 and D17.

The cathodes of the ninth light-emitting diode D9, the tenth light-emitting diode D10, the eleventh light-emitting diode D11, and the twelfth light-emitting diode D12 are respectively connected to the 3rd, 6th, 11th, 11th, 14-pin connection, the anode is connected to the power supply voltage through diodes D18 and D17.

The cathodes of the thirteenth light-emitting diode D13, the fourteenth light-emitting diode D14, the fifteenth light-emitting diode D15, and the sixteenth light-emitting diode D16 are respectively connected to the third, sixth, and fourth 74LS175 chips through resistors R13, R14, R15, and R16. Pins 11 and 14 are connected, and the anode is connected to the power supply voltage through diodes D18 and D17.

The terminal device 103 (not shown in the figure) is respectively connected to pins 2, 7, 10, and 15 of the first 74LS175 chip, the second 74LS175 chip, the third 74LS175 chip, and the fourth 74LS175 chip.

The terminal device 103 is configured to acquire the counting result, and generate the rotation angle data of the steering wheel according to the counting result and a pre-stored calculation formula. It should be noted that the counting result obtained by the terminal device is a binary counting result, and the obtained binary counting result is converted into a decimal counting result and the rotation angle of the steering wheel is calculated according to the rotation angle data acquisition formula.

The terminal equipment includes a data acquisition card for obtaining counting results.

The fixed photoelectric encoder 201 adopts 4096-line ABZ phase, and is coaxially connected with the steering wheel steering rod. Pulse signal output, when the shaft rotates 360 degrees, the fixed photoelectric encoder 201 will output the above-mentioned pulse number is 4096, when the clockwise rotation, the A-phase pulse leads the B-phase pulse by 90 degrees, and when the counter-clockwise rotation, the B-phase pulse leads the A Phase pulse 90 degrees. Since the steering wheel swings around the zero point most of the time during the driving process of the driver, the corner acquisition card will frequently collect forward and reverse pulses (on the pulse counting card, it is represented by frequent addition and subtraction pulse counting) ), so that after a period of time of collection, there will be cumulative errors, which will cause the zero position of the steering wheel on the test bench to drift, affecting the normal simulation of the wire-controlled car simulation test bench.

Since the fixed incremental photoelectric encoder is used, its zero point is fixed, and the zero point of the fixed incremental photoelectric encoder coincides with the zero point of the steering wheel during installation. In this way, whenever the steering wheel passes the preset zero position of the test bench, the fixed photoelectric encoder 201 will generate a Z-phase pulse signal, and this pulse signal can be used to clear the low-order signal of the pulse counter, so that the low-order signal can be eliminated. The accumulated pulse error generated by counting.

The specific clearing method is:

The fixed photoelectric encoder 201 generates a high-level Z-phase pulse signal, and the high-level Z-phase pulse signal is input to the first 40193 chip and the second 40193 chip through the inverter and the 11th pin of the first 40193 chip and the second 40193 chip Chip, the Z-phase pulse signal inverted by the inverter is low-level input, so when the first 40193 chip and the second 40193 chip detect that there is a low-level pulse input from pin 11, the third 40193 chip will be detected and whether the count value of the fourth 40193 chip is zero, that is, whether only the first 40193 chip and the second 40193 chip have a count value in the counter, and if so, the 9, 10, 1, and 15 pins of each 40193 count chip The parallel data of the parallel data is copied to the counter data output terminals of pins 2, 3, 6, and 7 respectively, so that the counting result clock of the high-order counting chip is zero when the steering wheel swings near the zero position for a long time, since the high-order counting chip 9, The zero-value parallel data output generated by pins 10, 1, and 15 is sequentially transmitted to the low-order counting chip, and the value of the low-order counting chip is reduced to zero in turn, thereby achieving the clearing of the accumulated pulse error generated by the low-order counting chip due to long-term counting. Zero effect.

The corner signal processor 102 includes a counter composed of four 40193 chips connected in series. Since 40193 is a 4-bit counter, four 40193 chips are connected in series to form a 16-bit counter. The 40193 chip is a binary counter, which is characterized in that it can judge whether to count by 1 or count by 1 according to the direction of the input pulse value of the input pin Clk.up (pin 5) and Clk.dn (pin 4). It just satisfies the phase difference between the A and B phase pulses of the fixed incremental photoelectric encoder due to the different turning of the steering wheel. Connect the A and B phase pulse output ports to the Clk.up and Clk.dn ports through the phase detector to complete the counting function, that is, to connect the A phase pulse output port to the CLK input of the D flip-flop G1 in the phase detector respectively end, the first input end of the first NAND gate N1, the first input end of the second NAND gate N2; the B-phase pulse output port is connected to the D input end of the D flip-flop G1 in the phase detector; the D flip-flop G1 The output terminal is connected to the second input terminal of the first NAND gate N1, the Q output terminal of the D flip-flop G1 is connected to the second input terminal of the second NAND gate N2, and the first and second NAND gates in the phase detector The output ends are respectively connected to the No. 5 and No. 4 pins of the first 40193 chip. At the same time, the high-level Z-phase pulse generated by the fixed incremental photoelectric encoder is connected to the No. 11 pin of the first 40193 chip and the second 40193 chip through an inverter composed of a triode to achieve low signal due to long time The effect of clearing the accumulated pulse error generated by counting. Since the counting value of the counter is in the form of two’s complement, each instantaneous counting value of the counter will change greatly during the counting process, which requires that the value of the 16-bit counter at the same time should be taken out at the same time when taking the corner value In order to achieve this requirement, four 74LS175D flip-flop integrated chips connected in series are designed in the circuit to keep the 16-bit value of the instantaneous corner. Input pins 4, 5, 12, and 13 of four 74LS175 chips are respectively connected to output pins 2, 3, 6, and 7 of four 40193 counting chips. At the same time, four groups of light-emitting diodes are designed, which are connected to the output pins 3, 6, 11, and 14 of the 74LS175D chip, and then turn on and off in real time according to the received binary 1 and 0 values, and pass through the 4 groups of LEDs. The status of the light on or off displays the change of the steering wheel angle information in real time. For example, the first light-emitting diode D1, the second light-emitting diode D2, the third light-emitting diode D3, and the fourth light-emitting diode D4 are respectively connected to the first 74LS175 chip. When the count value received by the first 74LS175 chip is 1001, the first light-emitting diode Diode D1 is on, the second LED D2 is off, the third LED D3 is off, and the fourth LED D4 is on; when the count value received by the first 74LS175 chip is 1110, the first LED D1 is on, and the second LED is on. D2 is on, the third light emitting diode D3 is on, and the fourth light emitting diode D4 is off.

The process of calculating the corresponding steering wheel angle according to the counting pulse of the steering wheel is as follows:

According to the vehicle handling stability test standard, the detection range of the steering wheel angle should meet ±1080° (that is, the steering wheel turns positively and negatively 3 times). In the actual measurement, the fixed incremental photoelectric encoder 201 sends out 4096 A-phase pulse signals and 4096 B-phase pulse signals every 360° with the steering wheel shaft, and when the steering wheel rotates forward (clockwise), the A-phase pulse leads The B-phase pulse is 90°, and when the steering wheel is reversed, the B-phase pulse is 90 degrees ahead of the A-phase pulse. When the steering wheel is turning forward, the A and B phase pulse signals generated by the photoelectric encoder are detected by the phase detector 203, and the counting pulse is sent to the No. 5 pulse input terminal CU of the first 40193 chip for counting up. At this time, the first 40193 The No. 4 CD end of the chip remains at the high level generated by the phase detector 203; when the steering wheel is reversed, the A and B phase pulse signals generated by the fixed incremental photoelectric encoder 201 are discriminated by the phase detector circuit, and the counting pulses are sent to The No. 4 downpulse input to the first 40193 chip is input to the CD terminal for counting down. At this time, the No. 5 CU terminal of the first 40193 chip remains at the high level generated by the phase detector 203 . When the steering wheel rotates, 4096 counting pulses are generated for each 360° rotation, and the steering wheel angle corresponding to each counting pulse is 360°/4096=0.0879°/piece, so it can be calculated by the counting value of the counting pulse in the actual measurement process To get the corresponding steering wheel angle, since the 40193 counting chip is a bidirectional counter, its counting value is in the form of two’s complement. The calculation method of the rotation angle value is different for forward rotation and reverse rotation. When the steering wheel starts to rotate forward from zero, the No. 5 CU side of the 40193 computing chip counts up according to the counting pulse. Since 40193 is a four-bit counter, four 40193 counters are cascaded to form a 16-bit counter. Whenever the low-bit counting chip counts four digits, 1 is carried to the high-bit counting chip through the No. 12 carry port of the 40193 chip. According to the vehicle handling stability The maximum forward rotation angle of the standard steering wheel in the test is 1080° for 3 turns, and 4096 calculation pulses are generated for every 360-degree rotation of the steering wheel, so the maximum pulse count value generated when the steering wheel is forward rotation is 4096×3=12288.

When the steering wheel starts to rotate forward (clockwise) from zero, there are two situations: first, when the steering wheel continues to rotate forward without returning to positive (counterclockwise), the 16-bit counter is continuously counting up, Its count value is sent to the terminal device 103 through the synchronous holder. It should be noted that the count value of the sixteen-bit counter is a binary count value, and the terminal device 103 converts the binary count value into a decimal count value and sets it as A, Then the calculation formula of the steering wheel angle at this time is: steering wheel angle=A×0.0879. And, whenever the sixteen-digit counter counts up once, the corresponding four groups of 16 light-emitting diodes will be turned on and off in real time according to the binary count value of the sixteen-digit counter, and the light-emitting diode corresponding to the binary value of 1 On, the light-emitting diode corresponding to the binary value of 0 is off, so the user can read the binary count value through the light-off situation of the light-emitting diode corresponding to the sixteen-bit counter, and then calculate the steering wheel angle; second, when the steering wheel is rotating forward When there is a positive (counterclockwise) rotation during the process, whenever the steering wheel rotates counterclockwise within the angle range of the forward rotation, the 16-digit counter will change from the previous up count to the down count. The counting value of the counter is gradually reduced by 1 each time on the basis of the original value until the counting pulse value is 0, that is, the steering wheel returns to zero, and the sixteen-digit counter turns from counterclockwise to clockwise. It will count up again. In this case, although there is a situation where the steering wheel is reversed (rotating counterclockwise), the sum of the count values of the steering wheel angles is always greater than zero, so the same as the first case, the count value of the sixteen-bit counter can be sent to the The terminal device 103, the terminal device 103 converts the binary count value into a decimal count value and sets it as A, then the calculation formula of the steering wheel angle at this time is still: steering wheel angle=A×0.0879.

When the steering wheel starts to reverse (rotate counterclockwise) from the zero position, there are two situations in the rotation of the steering wheel: the first situation is that the steering wheel continues to reverse and does not return to normal (rotate clockwise). The bit counter counts down from zero. At this time, the count value of the sixteen-bit counter is in the form of two's complement. When the steering wheel continues to reverse (counterclockwise) from the zero position, the count value of the count pulse decreases by 1 successively from zero, and the count value is a negative number, and the binary negative form is two’s complement, so the calculation value of the first count pulse is the 16-bit two’s complement of -1, and its value is 1111 1111 1111 1111 converted to a decimal value of 65535, at this time All 16 LEDs are on. After that, as the angle of steering wheel reversal (counterclockwise rotation) increases, the number of counting pulses continues to increase, and the decimal value of the counting pulse decreases by 1 each time starting from 65535 until the number of steering wheel reversal (counterclockwise rotation) reaches three circles , until the angle reaches 1080°. Therefore, when the steering wheel continues to reverse (rotate counterclockwise) from zero position, the calculation method of the count pulse count value is to send the count value of the sixteen-bit counter to the terminal device 103 through the synchronization holder, and the terminal device 103 counts the binary number The value is converted into a decimal count value and set to B, then the calculation formula of the steering wheel angle at this time is: steering wheel angle = [65535-(B-1)] × 0.0879; In the process of turning, there is a situation that the steering wheel turns back to normal (clockwise) (continuously back to normal until the steering wheel angle is zero or returns to a certain angle and the steering wheel continues to reverse), at this time, when the steering wheel starts to rotate forward, the counting pulse is sent to the ten The No. 5 plus pulse input terminal CU of the six-digit counter counts up, and the count value of the count pulse increases by 1 each time on the basis of the original value. In this case, although the steering wheel rotates forward, the overall rotation angle of the steering wheel is still relatively When the zero position is negative, the calculation method of the steering wheel angle is the same as in the previous case, and the count value of the sixteen-digit counter is still sent to the terminal device 103 through the synchronization holder, and the terminal device 103 converts the binary count value into a decimal count value, and set it as B, then the calculation formula of the steering wheel angle at this time is: steering wheel angle=[65535-(B-1)]×0.0879.

Whenever the shaft rotates 360 degrees, the fixed photoelectric encoder 201 will output 4096 pulses. According to this characteristic, the terminal equipment will set the corresponding relationship between the counting result and the steering wheel rotation angle. After obtaining the counting result, it will The corresponding relationship between the result and the steering wheel rotation angle generates the rotation angle data of the steering wheel.

In the real-time steering wheel angle acquisition system provided by the embodiment of the present invention, the angle signal collector generates a pulse signal according to the rotation of the steering rod of the steering wheel, and sends the generated pulse signal to the angle signal processor, and the angle signal processor receives the pulse signal according to the received The pulse signal is counted, and the counting result is sent to the terminal device. The terminal device generates the rotation angle data of the steering wheel according to the counting result and the pre-stored calculation formula. The structure has no influence, and at the same time, the signal collected by the system is consistent with other electronic control signals of the vehicle, and there will be no discrepancy, and the signal collection has high accuracy and fast speed.

It should be noted that, for the sake of simplicity of description, the aforementioned method embodiments are expressed as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence. Because of the present invention, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification belong to preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

In the foregoing embodiments, the descriptions of each embodiment have their own emphases, and for parts not described in detail in a certain embodiment, reference may be made to relevant descriptions of other embodiments.

The above is the description of the real-time steering wheel angle acquisition system provided by the present invention. For those skilled in the art, according to the idea of the embodiment of the present invention, there will be changes in the specific implementation and application range. In summary, this specification The content should not be construed as a limitation of the invention.

Claims (10)

1. A real-time steering wheel angle acquisition system, characterized in that the system comprises: Corner signal collector, corner signal processor and terminal equipment; The corner signal processor is respectively connected to the corner signal collector and the terminal device; The rotation angle signal collector is configured to generate a pulse signal according to the rotation of the steering wheel steering rod, and send the generated pulse signal to the rotation angle signal processor; The corner signal processor is configured to perform counting according to the received pulse signal, and send the counting result to the terminal device; The terminal device is configured to generate the rotation angle data of the steering wheel according to the counting result and a pre-stored calculation formula. 2. real-time steering wheel angle acquisition system as claimed in claim 1, is characterized in that, described angle signal collector is specifically fixed incremental photoelectric encoder; The fixed incremental photoelectric encoder is coaxially connected to the steering wheel steering rod, and the zero point position of the fixed incremental photoelectric encoder coincides with the zero point position of the steering wheel; When the steering rod rotates, the fixed incremental photoelectric encoder generates A and B phase pulse signals with a phase difference of 90°, and outputs them to the rotation angle signal processor; When the steering rod rotates clockwise, the A-phase pulse signal leads the B-phase pulse signal by 90°, and when the steering rod rotates counterclockwise, the B-phase pulse signal leads the A-phase pulse signal by 90°; When the steering rod passes the zero position of the fixed incremental photoelectric encoder, the fixed incremental photoelectric encoder generates a high-level Z-phase pulse signal. 3. real-time steering wheel angle acquisition system as claimed in claim 2, is characterized in that, described angle signal processor comprises: A sixteen-bit counter composed of four series-connected four-bit counters, and four series-connected synchronous holders; Four of the four-bit counters include: The first 40193 chip, the second 40193 chip, the third 40193 chip, and the fourth 40193 chip; The four Sync Keepers include: The first 74LS175 chip, the second 74LS175 chip, the third 74LS175 chip, and the fourth 74LS175 chip; The first 40193 chip is connected to the first 74LS175 chip, the second 40193 chip is connected to the second 74LS175 chip, the third 40193 chip is connected to the third 74LS175 chip, and the fourth 40193 chip is connected to the second 74LS175 chip. The chip is connected with the fourth 74LS175 chip. 4. real-time steering wheel angle acquisition system as claimed in claim 3, is characterized in that, described angle signal processor also comprises: phase detector; The A-phase pulse output port of the fixed incremental photoelectric encoder is connected to the 5th pin of the first 40193 chip through the phase detector, and the B-phase pulse output port of the fixed incremental photoelectric encoder connected to the 4th pin of the first 40193 chip through the phase detector; When the received A-phase pulse signal leads the B-phase pulse signal by 90°, the sixteen-bit counter counts up, and when the received B-phase pulse signal leads the A-phase pulse signal by 90°, the sixteen-bit counter counts down count. 5. real-time steering wheel angle acquisition system as claimed in claim 4, is characterized in that, The 12th pin of the first 40193 chip is connected to the 5th pin of the second 40193 chip, and the 13th pin of the first 40193 chip is connected to the 4th pin of the second 40193 chip; The 12th pin of the second 40193 chip is connected to the 5th pin of the third 40193 chip, and the 13th pin of the second 40193 chip is connected to the 4th pin of the third 40193 chip; The 12th pin of the third 40193 chip is connected to the 5th pin of the fourth 40193 chip, and the 13th pin of the third 40193 chip is connected to the 4th pin of the fourth 40193 chip; The 2nd, 3rd, 6th, 7th pins of the first 40193 chip are respectively connected with the 4th, 5th, 12th, 13th pins of the first 74LS175 chip; The 2nd, 3rd, 6th, and 7th pins of the second 40193 chip are respectively connected to the 4th, 5th, 12th, and 13th pins of the second 74LS175 chip; The 2nd, 3rd, 6th, and 7th pins of the third 40193 chip are respectively connected to the 4th, 5th, 12th, and 13th pins of the third 74LS175 chip; The 2nd, 3rd, 6th and 7th pins of the fourth 40193 chip are respectively connected to the 4th, 5th, 12th and 13th pins of the fourth 74LS175 chip. 6. real-time steering wheel angle acquisition system as claimed in claim 5, is characterized in that, described phase detector is made up of D flip-flop, the first NAND gate, the second NAND gate; The A-phase pulse output port of the fixed incremental photoelectric encoder is respectively connected to the CLK input end of the D flip-flop, the first input end of the first NAND gate, and the first input end of the second NAND gate. The input terminal is connected, the B-phase pulse output port of the fixed incremental photoelectric encoder is connected with the D input terminal of the D flip-flop, and the D flip-flop The output terminal is connected to the second input terminal of the first NAND gate, the Q output terminal of the D flip-flop is connected to the second input terminal of the second NAND gate, and the output of the first NAND gate terminal is connected with the 5th pin of the first 40193 chip, and the output terminal of the second NAND gate is connected with the 4th pin of the first 40193 chip; When the received A-phase pulse signal is ahead of the B-phase pulse signal by 90°, the D flip-flop The output terminal outputs a high-level signal, the Q output terminal of the D flip-flop outputs a low-level signal, the first NAND gate is opened, the second NAND gate is closed, and the sixteen-bit counter counts up; When the received B-phase pulse signal is ahead of the A-phase pulse signal by 90°, the D flip-flop The output terminal outputs a low level signal, the Q output terminal of the D flip-flop outputs a high level signal, the first NAND gate is closed, the second NAND gate is opened, and the sixteen-bit counter counts down. 7. real-time steering wheel angle acquisition system as claimed in claim 6, is characterized in that, described angle signal processor also comprises: inverter; The Z-phase pulse output port of the fixed incremental photoelectric encoder is respectively connected with the 11th pin of the first 40193 chip and the 11th pin of the second 40193 chip through an inverter; The inverter is used to convert the high-level Z-phase pulse signal into a low-level Z-phase pulse signal; The low-level Z-phase pulse signal is used to count the count values of the first 40193 chip and the second 40193 chip when the count values of the third 40193 chip and the fourth 40193 chip are zero to clear. 8. real-time steering wheel angle acquisition system as claimed in claim 7, is characterized in that, described angle signal processor also comprises: Power supply voltage, first light-emitting diode, second light-emitting diode, third light-emitting diode, fourth light-emitting diode, fifth light-emitting diode, sixth light-emitting diode, seventh light-emitting diode, eighth light-emitting diode, ninth light-emitting diode, tenth Light-emitting diodes, eleventh light-emitting diodes, twelfth light-emitting diodes, thirteenth light-emitting diodes, fourteenth light-emitting diodes, fifteenth light-emitting diodes, sixteenth light-emitting diodes; The cathodes of the first light-emitting diode, the second light-emitting diode, the third light-emitting diode, and the fourth light-emitting diode are respectively connected to the 3rd, 6th, 11th, and 14th pins of the first 74LS175 chip, and the anode is connected to the power supply voltage; The cathodes of the fifth light-emitting diode, the sixth light-emitting diode, the seventh light-emitting diode, and the eighth light-emitting diode are respectively connected to the 3rd, 6th, 11th, and 14th pins of the second 74LS175 chip, and the anode is connected to the power supply voltage; The cathodes of the ninth light-emitting diode, the tenth light-emitting diode, the eleventh light-emitting diode, and the twelfth light-emitting diode are respectively connected to pins 3, 6, 11, and 14 of the third 74LS175 chip, and the anode is connected to the power supply voltage; The cathodes of the thirteenth light-emitting diode, the fourteenth light-emitting diode, the fifteenth light-emitting diode, and the sixteenth light-emitting diode are respectively connected to the 3rd, 6th, 11th, and 14th pins of the fourth 74LS175 chip, and the anode is connected to the power supply voltage . 9. real-time steering wheel angle acquisition system as claimed in claim 8, is characterized in that, The terminal equipment is respectively connected to pins 2, 7, 10, and 15 of the first 74LS175 chip, the second 74LS175 chip, the third 74LS175 chip, and the fourth 74LS175 chip; The terminal device is configured to acquire the counting result, and generate the rotation angle data of the steering wheel according to the preset corresponding relationship between the counting result and the steering wheel rotation angle. 10. The real-time steering wheel angle acquisition system according to claim 9, wherein the terminal device includes a data acquisition card for obtaining counting results.