JP7025261B2 - Vehicle calculation device - Google Patents

Description

The present invention relates to a vehicle calculation device that calculates the rotation speed of a rotating body and determines the rotation direction of the rotating body.

Patent Document 1 describes an example of a calculation device for calculating the rotation angle of a rotating body such as a crank shaft. The sensor included in this calculation device outputs a pulse signal according to the rotation direction of the rotating body and the rotation speed of the rotating body. That is, when the rotating body is rotating in the first direction, the pulse width, which is the length of the period during which the level of the pulse signal is held at the "High" level, becomes the first width. On the other hand, when the rotating body is rotating in the second direction opposite to the first direction, the pulse width becomes a second width different from the first width. Therefore, the rotation direction of the rotating body can be determined by detecting the pulse width of the pulse signal.

Here, with reference to FIG. 8, an example will be described in which a pulse signal from such a sensor is input to an electronic circuit and a process of determining the rotation direction of the rotating body is executed by the CPU of the electronic circuit. As shown in FIG. 8, the electronic circuit 70 has a port 71 to which a pulse signal is input from the sensor 100. In the electronic circuit 70, when the rising edge is input to the port 71, the information about the time at this time is stored in the port register 72, and the CPU 73 is requested to execute the first interrupt process. Then, in the first interrupt process, the CPU 73 stores the information stored in the port register 72 in the RAM 74 as information regarding the time when the rising edge is input to the port 71. Further, when the falling edge is input to the port 71, the information regarding the time at this time is stored in the port register 72, and the CPU 73 is requested to execute the second interrupt process. Then, in the second interrupt process, the CPU 73 stores the information stored in the port register 72 in the RAM 74 as information regarding the time when the falling edge is input to the port 71. Then, the CPU 73 calculates the pulse width based on the information stored in the RAM 74 regarding the time when the rising edge is input to the port 71 and the information regarding the time when the falling edge is input to the port 71, and this pulse. The rotation direction of the rotating body is determined based on the width.

Japanese Unexamined Patent Publication No. 2006-38773

Even if the CPU 73 is requested to perform the first interrupt processing because the rising edge is input to the port 71, there may be interrupt processing that was requested to be executed before the first interrupt processing, or during the interrupt processing prohibition period. When the first interrupt processing is requested, the first interrupt processing may be executed after the falling edge is input to the port 71. In this case, the information stored in the port register 72 before the start of the first interrupt processing changes from the information about the time when the rising edge is input to the port 71 to the information about the time when the falling edge is input to the port 71. It will be rewritten. When the first interrupt process is executed in such a state, the information stored in the RAM 74 by the first interrupt process is not the information regarding the time when the rising edge is input to the port 71. As a result, the pulse width is calculated based on erroneous information, so that the rotation direction of the rotating body may not be correctly determined.

The vehicle calculation device for solving the above problems includes a rotor that rotates integrally with the rotating body, a pulse signal output unit that outputs a pulse signal according to the rotation direction of the rotor and the rotation speed of the rotor, and a pulse signal output unit. It is equipped with an electronic circuit to which a pulse signal output from is input. When the length of the period during which the pulse signal level is held at the "High" level is defined as the pulse width, the pulse signal output unit outputs a pulse signal with a shorter pulse generation interval as the rotation speed of the rotor increases, and the rotor A pulse signal including a pulse having a pulse width corresponding to the rotation direction of is output. The electronic circuit is information about the time when the first port and the second port to which the pulse signal is input and one of the rising edge and the falling edge are input to the first port. A port register that stores time information, a timer that measures the on-time, which is the length of the period during which the level of the pulse signal input to the second port is the "High" level, and determination of the rotation direction of the rotating body. , And a processing execution unit that calculates the rotation speed of the rotating body. Further, in the electronic circuit, when one of the above edges is input to the first port, the processing execution unit is requested to execute the first interrupt processing for storing the edge time information stored in the port register in the memory. When a falling edge is input to the second port, the processing execution unit is requested to execute the second interrupt processing for storing the on-time measured by the timer in the memory. Then, the processing execution unit determines the rotation direction of the rotating body based on the on-time stored in the memory by executing the second interrupt processing, and based on the edge time information stored in the memory by executing the first interrupt processing. Calculate the rotation speed of the rotating body.

According to the above configuration, when the rotor is integrally rotated with the rotating body, a pulse signal is input to the electronic circuit from the pulse signal output unit. Then, when one of the rising edge and the falling edge is input to the first port, the edge time information is stored in the port register, and the processing execution unit is requested to execute the first interrupt processing. Will be done. Further, when the rising edge is input to the second port, the on-time measurement by the timer is started. Then, when the falling edge is input to the second port, the on-time measurement by the timer is stopped, and the processing execution unit is requested to execute the second interrupt processing.

At the execution timing of the first interrupt process, the process execution unit executes the first interrupt process. In the first interrupt process, the edge time information stored in the port register is stored in the memory. In the above configuration, even if the other edge of the falling edge and the falling edge is input, the information stored in the port register is not rewritten to another information. Therefore, by executing the first interrupt process, information regarding the time when one of the edges is input to the first port can be stored in the memory as edge time information. As a result, the rotation speed of the rotating body can be calculated based on the information stored in the memory by executing the first interrupt process.

Further, the on-time measured by the timer is a value corresponding to the pulse width and is stored in the memory by executing the second interrupt process. Therefore, the rotation direction of the rotating body can be determined based on the on-time stored in the memory.

Therefore, according to the above configuration, even if the execution of the interrupt process due to the input of the edge to the port is delayed, it is possible to determine the rotation direction of the rotating body and calculate the rotation speed of the rotating body.

The rotation direction of the rotating body may be determined by the second interrupt process, but in this case, the execution time of the second interrupt process becomes long. When the execution time of interrupt processing becomes long in this way, the start of other interrupt processing to be executed next tends to be delayed.

Therefore, it is preferable that the processing execution unit executes the determination processing for determining the rotation direction of the rotating body every predetermined calculation cycle. According to this configuration, since the second interrupt process does not include the determination of the rotation direction of the rotating body, it is possible to suppress the execution time of the second interrupt process from becoming long. As a result, it is possible to prevent the execution timing of each interrupt process from being delayed.

Further, the rotation speed of the rotating body may be calculated by the first interrupt process, but in this case, the execution time of the first interrupt process becomes long. If the execution time of interrupt processing becomes long in this way, the start of other interrupt processing to be executed next is delayed.

Therefore, it is preferable that the processing execution unit executes a speed calculation process for calculating the rotation speed of the rotating body every specified calculation cycle. According to this configuration, since the first interrupt process does not include the calculation of the rotation speed of the rotating body, it is possible to suppress the execution time of the first interrupt process from becoming long. As a result, it is possible to prevent the execution timing of each interrupt process from being delayed.

In recent years, in order to realize running support of various vehicles and automatic running of vehicles, it is desired to be able to accurately determine the moving direction of the vehicle, that is, the rotation direction of the wheels. Therefore, the rotating body may be used as a wheel of the vehicle, and the rotor may be integrally rotated with the wheel. In this case, the rotation direction of the wheels can be determined by the vehicle calculation device, and the rotation speed of the wheels can be calculated.

The block diagram which shows the outline of one Embodiment of the calculation device of a vehicle. The block diagram which shows the outline of the rotation angle sensor of the calculation device. (A) to (c) are graphs showing the pulse signal output from the pulse signal output unit of the same rotation angle sensor. The schematic diagram which shows how the storage contents of RAM are updated by a CPU. A flowchart illustrating a speed calculation process executed by the CPU. A flowchart illustrating a determination process executed by the CPU. (A) to (e) are timing charts when a pulse signal is input to an electronic circuit from each rotation angle sensor. Conventionally, a schematic diagram showing a sensor and an electronic circuit that processes a pulse signal input from the sensor.

Hereinafter, an embodiment of the vehicle calculation device will be described with reference to FIGS. 1 to 7.
As shown in FIG. 1, the calculation device 20 of this embodiment is applied to a vehicle provided with a plurality of (four in this embodiment) wheels 11, 12, 13, and 14. The calculation device 20 includes the same number of rotation angle sensors 21, 22, 23, 24 as the wheels 11 to 14, and an electronic circuit 30 that determines the rotation direction of the wheels 11 to 14 and calculates the rotation speed VW of the wheels 11 to 14. And have. In this embodiment, the wheels 11 to 14 are an example of a "rotating body". Then, each rotation angle sensor 21 to 24 outputs a pulse signal corresponding to the rotation of the corresponding wheels 11 to 14 to the electronic circuit 30.

The electronic circuit 30 has a CPU 36 which is an example of a processing execution unit, a ROM 37 which stores various programs executed by the CPU 36, and a RAM 38 which temporarily stores the result of processing by the CPU 36. .. Further, the electronic circuit 30 is provided with the same number of input systems 31, 32, 33, 34 as the rotation angle sensors 21 to 24. That is, a pulse signal is input to the first input system 31 from the rotation angle sensor 21 for the first wheel 11, and a pulse signal is input to the second input system 32 from the rotation angle sensor 22 for the second wheel 12. Is entered. Further, a pulse signal is input to the third input system 33 from the rotation angle sensor 23 for the third wheel 13, and a pulse signal is input to the fourth input system 34 from the rotation angle sensor 24 for the fourth wheel 14. Is entered.

Each input system 31 to 34 has a first port 41 and a second port 42 to which a pulse signal from the corresponding rotation angle sensors 21 to 24 is input. Further, each of the input systems 31 to 34 is input to the port register 43 in which the edge time information Te, which is information about the time when the rising edge is input to the first port 41, is stored, and the second port 42. It has a timer 44 for measuring the on-time Ton, which is the length of the period during which the level of the pulse signal is the “High” level.

Next, the rotation angle sensors 21 to 24 will be described with reference to FIGS. 2 and 3.
As shown in FIG. 2, the rotation angle sensors 21 to 24 have a rotor 26 that rotates integrally with the corresponding wheels 11 to 14, and a detection system 27 attached to the vehicle body of the vehicle. In the rotor 26, the north pole and the south pole are alternately magnetized along the circumferential direction centered on the rotation axis Z of the wheels 11 to 14 and the rotor 26. The detection system 27 is provided with two rotation detectors 281,282 that detect changes in the magnetic field accompanying the rotation of the rotor 26. Each rotation detector 281,282 outputs a signal corresponding to the change of the detected magnetic field. Further, the detection system 27 is provided with a pulse signal output unit 29 to which signals from the rotation detectors 281,282 are input. The pulse signal output unit 29 generates a pulse signal according to the rotation speed and rotation direction of the rotor 26 based on the signals from both rotation detectors 281,282, and outputs this pulse signal.

The first rotation direction, which is the rotation direction of the wheels 11 to 14 for advancing the vehicle, is called the forward direction A1, and the second rotation direction, which is the rotation direction of the wheels 11 to 14 for retreating the vehicle, is the reverse direction. Let's call it A2. The backward direction A2 is the opposite direction of the forward direction A1. Examples of pulse signals when the wheels 11 to 14 and the rotor 26 are rotating in the forward direction A1 are shown in FIGS. 3 (a) and 3 (b). 3 (b) shows the rotation of the wheels 11 to 14 and the rotor 26 rather than the rotation speed of the wheels 11 to 14 and the rotor 26 when the pulse signal shown in FIG. 3 (a) is output from the pulse signal output unit 29. The pulse signal output from the pulse signal output unit 29 when the speed is high is shown in the figure.

As shown in FIGS. 3A and 3B, the pulse signal output unit 29 outputs a pulse signal having a short pulse generation interval INT to the electronic circuit 30 as the rotation speeds of the wheels 11 to 14 and the rotor 26 increase. do. However, when the length of the period during which the level of the pulse signal is held at the “High” level is defined as the pulse width PW, the pulse width PW in the pulse signal shown in FIG. 3 (a) and the pulse width PW shown in FIG. 3 (b) are shown. The pulse width PW in the pulse signal is equal to the first pulse width PW1. That is, when the wheels 11 to 14 and the rotor 26 are rotating in the forward direction A1, the pulse signal output unit 29 outputs a pulse signal including a pulse having a pulse width PW of the first pulse width PW1.

On the other hand, FIG. 3C shows an example of a pulse signal when the wheels 11 to 14 and the rotor 26 are rotating in the backward direction A2. Even when the wheels 11 to 14 and the rotor 26 rotate in the backward direction A2, the pulse signal output unit 29 has a pulse signal having a shorter pulse generation interval INT as the rotation speed of the wheels 11 to 14 and the rotor 26 increases. Is output to the electronic circuit 30. However, the pulse width PW of the pulse included in the pulse signal shown in FIG. 3C is equal to the second pulse width PW2 shorter than the first pulse width PW1. That is, in the present embodiment, when the rotation direction of the wheels 11 to 14 and the rotor 26 is the backward direction A2, the pulse signal output unit 29 has a pulse width PW as compared with the case where the rotation direction is the forward direction A1. Outputs a pulse signal containing different pulses.

Next, with reference to FIGS. 1 and 4 to 6, various processes executed by the electronic circuit 30 will be described.
As shown in FIG. 1, the same pulse signal is input to the paired first port 41 and the second port 42. For example, a pulse signal from the rotation angle sensor 21 for the first wheel 11 is input to the first port 41 and the second port 42 of the first input system 31. Then, when the rising edge is input to the first port 41, the edge time information Te, which is information about the time when the rising edge is input to the first port 41, is stored in the port register 43. That is, the information stored in the port register 43 is rewritten each time a rising edge is input to the first port 41. Further, when the rising edge is input to the first port 41, the CPU 36 is requested to execute the first interrupt process.

When the rising edge is input to the second port 42, the timer 44 starts the measurement of the on-time Ton. Then, when the falling edge is input to the second port 42, the on-time Ton measurement by the timer 44 is stopped. Further, when a falling edge is input to the second port 42, the CPU 36 is requested to execute the second interrupt process.

As shown in FIG. 4, in the first interrupt process, the CPU 36 stores the edge time information Te stored in the port register 43 in a predetermined area of the RAM 38, which is an example of the memory, and is stored in the RAM 38. The update counter Cu is incremented by "1". Specifically, the RAM 38 contains a storage area 381 for the first wheel 11, a storage area 382 for the second wheel 12, a storage area 383 for the third wheel 13, and storage for the fourth wheel 14. Area 384 is prepared in advance. Then, for example, in the first interrupt processing requested to be executed because the rising edge is input to the first port 41 of the first input system 31, the CPU 36 stores it in the port register 43 of the first input system 31. The edge time information Te is overwritten and stored in the storage area 381 for the first wheel 11, and the update counter Cu in the storage area 381 is updated. The content of the first interrupt processing required to be executed because the rising edge is input to the first port 41 of the other input systems 32 to 34 other than the first input system 31 is the first input system. Since it is equivalent to the content of the first interrupt processing required to be executed because the rising edge is input to the first port 41 of 31, the description thereof is omitted.

As shown in FIG. 4, in the second interrupt process, the CPU 36 stores the on-time Ton measured by the timer 44 in a predetermined area of the RAM 38. For example, in the second interrupt processing requested to be executed because the falling edge is input to the second port 42 of the first input system 31, the CPU 36 is measured by the timer 44 of the first input system 31. The on-time Ton is overwritten and stored in the storage area 381 for the first wheel 11. The content of the second interrupt processing required to be executed because the falling edge is input to the second port 42 of the other input systems 32 to 34 other than the first input system 31 is the first input. Since it is equivalent to the content of the second interrupt processing requested to be executed because the falling edge is input to the second port 42 of the system 31, the description thereof is omitted.

In addition to the first interrupt process and the second interrupt process, the CPU 36 executes a determination process for determining the rotation direction of the wheels 11 to 14 and a speed calculation process for calculating the rotation speed VW of the wheels 11 to 14. In the present embodiment, the CPU 36 executes the determination process and the speed calculation process every specified calculation cycle. That is, the determination of the rotation direction of the wheels 11 to 14 and the calculation of the rotation speed VW of the wheels 11 to 14 are performed separately from the first interrupt processing and the second interrupt processing. The temporal length of the calculation cycle is sufficiently longer than the larger pulse width of the first pulse width PW1 and the second pulse width PW2.

FIG. 5 shows a flowchart illustrating the speed calculation process. In the speed calculation process, the CPU 36 reads the update counter Cu for the Nth wheel from the RAM 38 (S11). The update counter Cu for the Nth wheel is an update counter Cu stored in the storage area for the Nth wheel in the RAM 38. For example, when the coefficient N is "1", the CPU 36 reads the update counter Cu from the storage area 381 for the first wheel 11.

Subsequently, the CPU 36 calculates the rotation speed VW of the Nth wheel based on the read update counter Cu for the Nth wheel (S12). The update counter Cu is the number of times a rising edge is input to the first port 41 from the time when the speed calculation process is executed last time to the time when the speed calculation process is executed this time. In the pulse signal output from the pulse signal output unit 29, the higher the rotation speed of the wheels 11 to 14, the shorter the pulse generation interval INT. Therefore, it can be said that the larger the update counter Cu, the higher the rotation speed of the wheels 11 to 14. Therefore, in step S12, the CPU 36 calculates the rotation speed VW of the Nth wheel so that the rotation speed VW increases as the read update counter Cu increases.

Then, the CPU 36 resets the update counter Cu for the Nth wheel to “0” (S13). That is, the CPU 36 resets the update counter Cu stored in the storage area for the Nth wheel in the RAM 38 to “0”. For example, when the coefficient N is "1", the CPU 36 resets the update counter Cu of the storage area 381 for the first wheel 11 to "0". Subsequently, the CPU 36 increments the coefficient N by "1" (S14), and determines whether or not the coefficient N is larger than "4" (S15). In the present embodiment, since the number of rotation angle sensors 21 to 24 is "4", the determination using the coefficient N and "4" is performed in step S15. When the coefficient N is "4" or less, it is not determined that the calculation of the rotation speed VW of all the wheels 11 to 14 in the current speed calculation process is completed. On the other hand, when the coefficient N is larger than "4", it is determined that the calculation of the rotation speed VW of all the wheels 11 to 14 in the current speed calculation process is completed.

Therefore, when the coefficient N is “4” or less (S15: NO), the CPU 36 executes the process of step S11 described above. On the other hand, when the coefficient N is larger than "4" (S15: YES), the CPU 36 makes the coefficient N equal to "1" (S16). After that, the CPU 36 ends the speed calculation process.

FIG. 6 shows a flowchart illustrating the determination process. In the determination process, the CPU 36 reads the on-time Ton for the Mth wheel from the RAM 38 (S21). The on-time Ton for the Mth wheel is an on-time Ton stored in the storage area for the Mth wheel in the RAM 38. For example, when the coefficient M is "1", the CPU 36 reads out the on-time Ton from the storage area 381 for the first wheel 11. Subsequently, the CPU 36 determines whether or not the read-out on-time Ton for the Mth wheel is equal to or longer than the direction determination time TonTh (S22). The direction determination time TonTh is set to be shorter than the first pulse width PW1 and longer than the second pulse width PW2. Therefore, when the on-time Ton for the Mth wheel is equal to or longer than the direction determination time TonTh (S22: YES), the CPU 36 determines that the rotation direction of the Mth wheel is the forward direction A1 (S23). Then, the CPU 36 shifts the process to step S25, which will be described later. On the other hand, when the on-time Ton for the Mth wheel is less than the direction determination time TonTh (S22: NO), the CPU 36 determines that the rotation direction of the Mth wheel is the backward direction A2 (S24). Then, the CPU 36 shifts the process to the next step S25.

In step S25, the CPU 36 increments the coefficient M by "1". Subsequently, the CPU 36 determines whether or not the coefficient M is larger than "4" (S26). In the present embodiment, since the number of rotation angle sensors 21 to 24 is "4", the determination using the coefficient M and "4" is performed in step S26. Therefore, when the coefficient M is "4" or less, it is not determined that the determination of the rotation directions of all the wheels 11 to 14 in the present determination process is completed. On the other hand, when the coefficient M is larger than "4", it is determined that the determination of the rotation directions of all the wheels 11 to 14 in the present determination process is completed. Then, when the coefficient M is "4" or less (S26: NO), the CPU 36 executes the process of step S21 described above. On the other hand, when the coefficient M is larger than "4" (S26: YES), the CPU 36 makes the coefficient M equal to "1" (S27). After that, the CPU 36 ends the determination process.

Next, the operation and effect of this embodiment will be described with reference to FIG. 7. In FIG. 7 (e), "PIP1" represents a determination process executed in each specified calculation cycle, and "PIP2" represents a speed calculation process executed in each specified calculation cycle. There is. Further, "IP1" represents the first interrupt processing, and "IP2" represents the second interrupt processing. If the data (edge time information Te, update counter Cu, on-time Ton, etc.) used in the process is updated during the execution of the determination process (PIP1) and the speed calculation process (PIP2), the calculation result in the process is updated. May be mistaken. Therefore, the execution of the first interrupt process (IP1) and the second interrupt process (IP2) is prohibited during the execution of the determination process (PIP1) and the speed calculation process (PIP2). Specifically, for example, when the rising edge is input during the execution of the judgment processing (PIP1) after the interrupt is disabled at the beginning of the judgment processing (PIP1), the information about the time when the rising edge is input is the port register 43. It is stored in and is requested to execute the first interrupt processing (IP1). However, the CPU 36 does not accept the execution request of the first interrupt process (IP1) until the interrupt prohibition is released. In the example shown in FIG. 7, the determination process (PIP1) and the speed calculation process (PIP2) are treated as continuous processes, interrupts are prohibited at the start of execution of the determination process (PIP1), and the speed calculation process (PIP2) is performed. Interrupt prohibition is canceled at the end of execution.

In the example shown in FIGS. 7 (a), (b), (c), (d), and (e), the first and second inputs of the first input system 31 at time t11 when the determination process is executed. A rising edge is input to each of the ports 41 and 42. Then, the information about the time t11 is stored in the port register 43 of the first input system 31 as the information about the time when the rising edge is input to the first port 41, and the on-time by the timer 44 of the first input system 31 is stored. Ton measurement is started. Further, at this time, the CPU 36 is required to execute the first interrupt process. However, at time t11, the determination process is being executed and the speed calculation process has not yet been executed, so that the first interrupt process is not yet executed.

Further, at the subsequent time t12, rising edges are input to the first and second ports 41 and 42 of the second input system 32. Then, the information about the time t12 is stored in the port register 43 of the second input system 32 as the information about the time when the rising edge is input to the first port 41, and is turned on by the timer 44 of the second input system 32. The measurement of time Ton is started. Further, at this time, the CPU 36 is required to execute the first interrupt process. However, at time t12, the determination process is still being executed, and the speed calculation process and the first interrupt due to the rising edge being input to the first port 41 of the first input system 31. The process has not been executed yet. Therefore, the first interrupt processing due to the rising edge being input to the first port 41 of the second input system 32 is not yet executed.

Then, when the execution of the determination process is completed, the execution of the speed calculation process is started. At time t13 when the speed calculation process is being executed, rising edges are input to the first and second ports 41 and 42 of the third input system 33. Then, the information about the time t13 is stored in the port register 43 of the third input system 33 as the information about the time when the rising edge is input to the first port 41, and the on-time by the timer 44 of the third input system 33 is stored. Ton measurement is started. Further, at this time, the CPU 36 is required to execute the first interrupt process.

Further, at the subsequent time t14, rising edges are input to the first and second ports 41 and 42 of the fourth input system 34. Then, the information about the time t14 is stored in the port register 43 of the fourth input system 34 as the information about the time when the rising edge is input to the first port 41, and the on-time by the timer 44 of the fourth input system 34 is stored. Ton measurement is started. Further, at this time, the CPU 36 is required to execute the first interrupt process.

In the example shown in FIG. 7, at time t14, falling edges are input to the first and second ports 41 and 42 of the first input system 31. Then, the measurement of the on-time Ton by the timer 44 of the first input system 31 is stopped, and the execution of the second interrupt process is requested. However, at this point, the speed calculation process is still being executed, and each first interrupt process is not yet executed. Therefore, the second interrupt process is not yet executed.

When the execution of the speed calculation process is completed at the subsequent time t15, the execution of the first interrupt process due to the rising edge being input to the first port 41 of the first input system 31 is started. At time t15, falling edges have already been input to the first and second ports 41 and 42 of the first input system 31. However, in the present embodiment, even if the falling edge is input to the first port 41, the information stored in the port register 43 is not rewritten. Therefore, even if the first interrupt process is executed after the falling edge is input to the first port 41 of the first input system 31, the information about the time t11 is stored for the first wheel 11 in the RAM 38. It can be stored in the area 381.

When the execution of the first interrupt processing due to the rising edge being input to the first port 41 of the first input system 31 at time t16 is completed, the first port 41 of the second input system 32 is used. The first interrupt processing due to the input of the rising edge is executed. In this first interrupt process, information about the time t12 is stored in the storage area 382 for the second wheel 12 in the RAM 38.

In the present embodiment, pulse signals are input to the electronic circuit 30 from the plurality of rotation angle sensors 21 to 24, respectively. Then, every time a rising edge is input to each of the first ports 41, the CPU 36 is requested to execute the first interrupt process. Therefore, the time lag between the time when the CPU 36 is requested to execute the first interrupt process and the time when the first interrupt process is actually executed by the CPU 36 tends to be large. In this respect, in this embodiment, two ports 41 and 42 are provided for one rotation angle sensor, and even if a falling edge is input to the first port 41 of the ports 41 and 42, respectively. , The information stored in the port register 43 cannot be rewritten. Therefore, even if the first interrupt processing is executed after the falling edge is input to the first port 41, the RAM 38 stores information about the time when the rising edge is input to the first port 41. Can be made to. Therefore, the rotation speed VW of the wheels 11 to 14 can be calculated by the speed calculation process.

When the execution of the first interrupt processing due to the rising edge being input to the first port 41 of the fourth input system 34 at time t17 is completed, the second port 42 of the first input system 31 is used. The second interrupt processing due to the input of the falling edge is executed. In this second interrupt process, the on-time Ton measured by the timer 44 of the first input system 31 is stored in the storage area 381 for the first wheel 11 in the RAM 38. Then, when the execution of the second interrupt processing due to the falling edge being input to the second port 42 of the first input system 31 at time t18 is completed, the second of the second input system 32 The second interrupt processing due to the input of the falling edge to the port 42 is executed. In this second interrupt process, the on-time Ton measured by the timer 44 of the second input system 32 is stored in the storage area 382 for the second wheel 12 in the RAM 38.

In the present embodiment, by executing the second interrupt process, the on-time Ton corresponding to the pulse width PW included in the pulse signal input to the second port 42 is stored in the RAM 38. Therefore, the rotation direction of the wheels 11 to 14 can be determined by executing the determination process without storing the information regarding the time when the falling edge is input to the first port 41 in the port register 43.

In addition to the above effects, the following effects can be further obtained in the present embodiment.
(1) When the determination of the rotation direction of the wheel 11 is performed by the second interrupt process, the execution time of the second interrupt process becomes long. When the execution time of the second interrupt process becomes long in this way, the start of another interrupt process to be executed next tends to be delayed. In this respect, in the present embodiment, the rotation direction of the wheel 11 is determined not by the second interrupt process but by the process executed every predetermined calculation cycle. As a result, it is possible to prevent the execution time of the second interrupt process from becoming long because the second interrupt process does not include the determination of the rotation direction of the wheels 11 to 14. As a result, it is possible to prevent the execution timing of each interrupt process from being delayed.

(2) When the rotation speed VW of the wheels 11 to 14 is calculated by the first interrupt process, the execution time of the first interrupt process becomes long. If the execution time of the first interrupt process becomes long in this way, the start of another interrupt process to be executed next is delayed. In this respect, in the present embodiment, the rotation speed VW of the wheels 11 to 14 is calculated by the process executed every predetermined calculation cycle instead of the first interrupt process. As a result, it is possible to prevent the execution time of the first interrupt processing from becoming long because the first interrupt processing does not include the calculation of the rotation speed VW of the wheels 11 to 14. As a result, it is possible to prevent the execution timing of each interrupt process from being delayed.

The above embodiment can be modified and implemented as follows. The above embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
-In the above embodiment, the execution cycle of the determination process is the same as the execution cycle of the speed calculation process. However, the execution cycle of the determination process and the execution cycle of the speed calculation process may be different from each other. In this case, the determination process and the speed calculation process are not continuously executed. Therefore, the execution of the interrupt process is prohibited at the start of the execution of the determination process, and the execution prohibition of the interrupt process is released at the end of the execution of the determination process. Similarly, the execution of the interrupt process is prohibited at the start of the execution of the speed calculation process, and the execution prohibition of the interrupt process is canceled at the end of the execution of the same speed calculation process.

-The determination of the rotation direction of the wheels 11 to 14 may be performed in the second interrupt process. In this case, for example, in the second interrupt processing caused by the falling edge being input to the second port 42 of the first input system 31, the on-time Ton measured by the timer 44 is used as the first of the RAM 38. It may be stored in the storage area 381 for the wheel 11 and the rotation direction of the first wheel 11 may be determined based on the on-time Ton stored in the storage area 381. Similarly, in the second interrupt processing caused by, for example, the falling edge being input to the second port 42 of the second input system 32, the on-time Ton measured by the timer 44 is used as the second input of the RAM 38. It may be stored in the storage area 382 for the wheel 12 and the rotation direction of the second wheel 12 may be determined based on the on-time Ton stored in the storage area 382.

-The rotation speed VW of the wheels 11 to 14 may be calculated in the first interrupt process. In this case, in the first interrupt processing caused by the rising edge being input to the first port 41 of the first input system 31, the edge time information Te stored in the port register 43 is used as the first RAM 38. It may be stored in the storage area 381 for the wheel 11 and the rotation speed VW of the first wheel 11 may be calculated based on the edge time information Te stored in the storage area 381.

The rotation speed VW of the wheels 11 to 14 may be calculated by a method different from the method described in the above embodiment. For example, the latest value of the edge time information Te and the previous value of the edge time information Te are stored in the RAM 38, and the latest value of the edge time information Te and the previous value of the edge time information Te stored in the RAM 38 are used as the basis. In addition, the interval at which the rising edge is input to the first port 41 is calculated. Then, the rotation speed VW may be calculated so that the rotation speed VW of the wheels increases as the interval becomes shorter.

When a falling edge is input to the first port 41, information about the time at that time is stored in the port register 43 as edge time information Te, and the CPU 36 is requested to execute the first interrupt processing. You may. In this case, even if the rising edge is input to the first port 41, the information stored in the port register 43 is not rewritten. Then, in the speed calculation process, the rotation speed VW of the wheel is calculated based on the information regarding the time when the falling edge is input to the first port 41 stored in the RAM 38.

The rotation angle sensors 21 to 24 may have a configuration different from the configuration described in the above embodiment as long as the configuration can output a pulse signal according to the rotation speed and the rotation direction of the rotor 26.
-In the above embodiment, a rotation angle sensor capable of outputting a pulse signal according to the rotation speed and the rotation direction of the rotor 26 is provided for all the wheels 11 to 14. However, for some of the wheels 11 to 14, a rotation angle sensor capable of outputting a pulse signal according to the rotation speed and rotation direction of the rotor is provided, and for the remaining wheels, the rotation speed of the rotor is provided. A type of rotation angle sensor may be provided in which the pulse width does not change depending on the rotation direction, although the pulse generation interval changes according to the above. Even in this case, the moving direction of the vehicle can be determined based on the pulse signal output from the rotation angle sensor provided for some of the wheels.

-In the above embodiment, the vehicle calculation device is embodied in the calculation device 20 including the rotation angle sensors 21 to 24 for the wheels 11 to 14, but the device including the rotation angle sensors for other rotating bodies other than the wheels. It may be embodied in. For example, the vehicle calculation device may be embodied in a device including a rotation angle sensor for the crank shaft of an in-vehicle engine. In this case, the calculation device can calculate the rotation speed of the crank shaft, which is an example of the rotating body, and determine the rotation direction of the crank shaft. Further, the vehicle calculation device may be embodied as a device provided with a rotation angle sensor for the rotation axis of the in-vehicle electric motor. In this case, the calculation device can calculate the rotation speed of the rotation shaft of the electric motor, which is an example of the rotating body, and determine the rotation direction of the rotation shaft.

11-14 ... Wheels as an example of a rotating body, 20 ... Calculation device, 26 ... Rotor, 29 ... Pulse signal output unit, 30 ... Electronic circuit, 36 ... CPU as an example of processing execution unit, 38 ... An example of memory A RAM, 41 ... first port, 42 ... second port, 43 ... port register, 44 ... timer.

Claims (4)

A rotor that rotates integrally with the rotating body, a pulse signal output unit that outputs a pulse signal according to the rotation direction of the rotor and the rotation speed of the rotor, and an electron to which a pulse signal output from the pulse signal output unit is input. With a circuit,
When the length of the period during which the pulse signal level is held at the "High" level is defined as the pulse width, the pulse signal output unit outputs a pulse signal having a shorter pulse generation interval as the rotation speed of the rotor increases. , A pulse signal including a pulse having the pulse width corresponding to the rotation direction of the rotor is output.
The electronic circuit is
The first port and the second port to which the pulse signal is input,
A port register in which edge time information, which is information regarding the time when one of the rising edge and the falling edge is input to the first port, is stored, and
A timer for measuring the on-time, which is the length of the period during which the level of the pulse signal input to the second port is the "High" level,
It has a processing execution unit that determines the rotation direction of the rotating body and calculates the rotation speed of the rotating body.
In the electronic circuit, when one of the edges is input to the first port, the process execution unit executes a first interrupt process for storing the edge time information stored in the port register in a memory. When a falling edge is input to the second port, the process execution unit is requested to execute a second interrupt process for storing the on-time measured by the timer in the memory. It has become like
The processing execution unit determines the rotation direction of the rotating body based on the on-time stored in the memory by executing the second interrupt processing, and stores it in the memory by executing the first interrupt processing. A vehicle calculation device that calculates the rotation speed of the rotating body based on the edge time information. The vehicle calculation device according to claim 1, wherein the processing execution unit executes a determination process for determining the rotation direction of the rotating body in each specified calculation cycle. The vehicle calculation device according to claim 1 or 2, wherein the processing execution unit executes a speed calculation process for calculating the rotation speed of the rotating body in each specified calculation cycle. The vehicle calculation device according to any one of claims 1 to 3, wherein the rotating body is a wheel of a vehicle, and the rotor rotates integrally with the wheel.

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