JP2005070060A - Wheel speed detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect precisely an abnormality of a rotary pulse train signal for wheel speed detection. <P>SOLUTION: Sensor units 20a-20d output rotation detection signals Vsj(j=1-4) for showing rotation of rotors 10a-10d rotating integrally with each wheel respectively. The rotation detection signals Vsj are pulse train signals for showing rotation speeds and rotation directions of the rotors 10a-10d. A microcomputer 40 and a rotation direction detection part 50 detect the rotation direction and the speed of the wheel based on the rotation detection signals Vsj. The microcomputer 40 determines an abnormality of the rotation detection signals Vsj on condition that the rotation direction of the wheel is a direction for retreating a vehicle, and that the calculated rotation speed is higher than a prescribed value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention comprises a pulse train whose cycle is shortened as the rotational speed of the rotor that rotates integrally with the wheel increases, and that each pulse of the pulse train includes a direction signal indicating forward rotation and reverse rotation of the rotor. The present invention relates to a wheel speed detection device that detects the rotation direction and speed of a wheel based on a pulse train signal.

Conventionally, as described in, for example, Non-Patent Document 1 below, this type of device is composed of a pulse train whose pulse width and period become shorter as the rotational speed of the rotor that rotates integrally with the wheel increases, and the rotor rotates in reverse. A rotation pulse signal generator for generating a rotation pulse train signal in which a narrow direction pulse is superimposed on the pulse train at the rise and fall timing of the pulse train according to the rotation of the rotor. The rotational direction of the wheel is detected based on the presence or absence of a direction pulse in the rotational pulse train signal from the rotational pulse signal generator, and the wheel speed is calculated according to the period of the rotational pulse train signal. Further, this wheel speed detecting device is adapted to determine abnormality of the rotation pulse train signal when the direction pulse is present only at one of the rising and falling timings of each pulse of the rotation pulse train signal.
Toyota Technology Disclosure, published on June 30, 1998, pages 193-199

  Such a conventional device can detect whether the wheel is moving forward or backward, and thus is extremely effective as a device for detecting the wheel speed. However, the document discloses only dealing with an extremely rare abnormal case in which a directional pulse exists only at one of the rising and falling timings of each pulse of the rotation pulse train signal. On the other hand, abnormalities in the rotation pulse train signal appear in various ways, and these abnormalities cannot be dealt with.

  The present invention has been made to cope with the above-described problems, and an object of the present invention is to provide a wheel speed detection device capable of dealing with an abnormal rotation pulse train signal having a mode different from that described above.

  A feature of the present invention is that it consists of a pulse train whose cycle is shortened as the rotational speed of the rotor that rotates integrally with the wheel increases, and that the rotation pulse train signal including the direction signal indicating the forward rotation and reverse rotation of the rotor is used. Wheel speed calculation means for detecting the rotation direction of the wheel based on the rotation pulse signal generating means generated according to the rotation of the rotation pulse and the direction signal included in the rotation pulse train signal, and calculating the wheel speed according to the period of the rotation pulse train signal Means for generating a rotation pulse signal when the detected wheel rotation direction is a direction for moving the vehicle backward and the calculated wheel speed is greater than a predetermined value. An abnormality determining means for determining an abnormality of the rotation pulse train signal generated from the means is provided.

  In the above configuration, when a normal rotation pulse train signal is output from the rotation pulse signal generation means, the wheel speed calculation means can detect the rotation direction of the wheel well and can calculate the wheel speed well. . On the other hand, if the rotation pulse train signal indicates the direction for moving the vehicle backward and indicates a large wheel speed due to a failure of the rotation pulse signal generation means, etc., the abnormality determination means determines that the rotation pulse train signal is abnormal. Is done. This is based on the fact that the speed does not become so high when the vehicle moves backward, and by setting the predetermined value to an appropriate value, it is possible to easily detect an abnormality in the rotation pulse train signal.

  In the feature of the present invention, as a condition for determining the abnormality of the rotation pulse train signal, the first condition relating to the rotation direction and the wheel speed may be added to one of the following second and third conditions or Both conditions may be added.

  The second condition is to determine abnormality of the rotation pulse train signal when the determination condition regarding the rotation direction continues to be satisfied for a predetermined time or more. According to this, it is possible to avoid erroneous determination of abnormality of the rotation pulse train signal due to the instantaneous establishment of the conditions regarding the rotation direction and the wheel speed.

  The third condition is to determine whether the rotation pulse train signal is abnormal when the minimum wheel speed of the plurality of wheel speeds is greater than the predetermined wheel speed. According to this, it is possible to avoid erroneous determination of abnormality due to the rotation of other wheels being stopped and only some of the wheels including the corresponding wheels are idling.

  Hereinafter, a wheel speed detection device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 schematically shows the entire wheel speed detection device.

  The wheel speed detection device includes four rotors 10a to 10d that rotate integrally with the left and right front and rear wheels, and the rotation of each wheel is detected by the sensor units 20a to 20d. The rotors 10a to 10d are made of a magnetic material and have a disk shape, and have a plurality of equally spaced teeth on the outer peripheral surface. The sensor unit 20a is composed of a magnetoresistive element, and includes rotation sensors 21a and 22a arranged to face each tooth of the rotor 10a. The rotation sensor 21a and the rotation sensor 22a are arranged by being shifted by π / 2 when the crests and troughs of the teeth of the rotor 10a are 2π. As the rotor 10a rotates, as shown in FIG. Outputs sinusoidal signals A and B that are out of phase by / 2. In addition, as these rotation sensors 21a and 22a, an electromagnetic pick-up, a Hall element, etc. can also be utilized without using a magnetoresistive element. Since the sensor units 20b to 20d are also configured in the same manner as the sensor unit 20a, only the sensor unit 20a is described and the description thereof is omitted.

  Waveform shaping circuits 23a and 24a are connected to the rotation sensors 21a and 22a, respectively, and the waveform shaping circuits 23a and 24a are connected to sinusoidal signals A and A as shown in FIGS. B is converted into rectangular wave signals C and D each having a duty ratio of approximately ½. These rectangular wave signals C and D are supplied to the logic synthesis circuit 27a via the delay circuits 25a and 26a, and are directly supplied to the logic synthesis circuit 27a. The delay circuits 25a and 26a delay the input rectangular wave signals C and D by a predetermined minute time (for example, 150 μs) to logically output the delay signals dC and dD as shown in FIGS. The result is output to the synthesis circuit 27a.

  The logic synthesis circuit 27a is composed of an AND circuit, an inverter circuit, an OR circuit, an exclusive OR circuit, and the like. The logic synthesis circuit 27a performs logic synthesis on the rectangular wave signals C and D and the delay signals dC and dD. The logic synthesis signals E and F shown in FIG. In this case, the logic synthesis signal E is synthesized by exclusive OR of the rectangular wave signals C and D. The logic synthesis signal F is synthesized by a logical expression Cvar · D · dDvar + C · Dvar · dD + C · D · dCvar + Cvar · Dvar · dC using the rectangular wave signals C and D and the delay signals dC and dD. However, Cvar, dCvar, Dvar, and dDvar are signals obtained by logically inverting C, dC, D, and dD.

  These logic synthesis signals E and F are output to the waveform synthesis circuit 28a. The waveform synthesis circuit 28a is composed of a reference voltage source circuit, a switching circuit, and the like, and synthesizes and outputs a rotation detection signal Vs1 as shown in FIGS. 3A and 3B based on the logic synthesis signals E and F. The rotation detection signal Vs1 has the highest priority voltage value V2 when the logic synthesis signal F is at a high level, and has a voltage value V1 when the logic synthesis signal F is not at a high level and the logic synthesis signal E is at a high level. When the combined signals E and F are both at the low level, the voltage value V0 is obtained. However, the relationship between the voltage values V0, V1, and V2 is 0 = V0 <V1 <V2.

  As a result, during the forward rotation of the rotor 10a (corresponding to the forward rotation of the wheel for advancing the vehicle), the rotation detection signal Vs1 has the voltage values V0 and V1 alternately as shown in FIG. It becomes a pulse train signal composed of repeating rectangular wave signals. On the other hand, during the reverse rotation of the rotor 10a (corresponding to the reverse rotation of the wheel for reversing the vehicle), the rotation detection signal Vs1 is generated at the rise and fall of the rectangular wave signal as shown in FIG. The pulse train signals each have a narrow pulse having a voltage value V2. Note that the pulse width and period of these pulse train signals are inversely proportional to the rotational speed (wheel speed) of the rotor 10a. The sensor units 20b to 20d also output rotation detection signals Vs2 to Vs4 that are the same as the rotation detection signal Vs1 and represent the rotation of the rotors 10b to 10d.

  The rotation detection signal Vs1 from the sensor unit 20a is supplied to each positive side input (+) of the comparators 31a and 32a. Reference voltages Vref1 and Vref2 from reference voltage sources 33a and 34a are supplied to the negative side inputs (−) of the comparators 31a and 32a, respectively. The relationship between the reference voltages Vref1, Vref2 and the voltage values V0, V1, V2 is V0 <Vref1 <V1 <Vref2 <V2. Therefore, if the rotor 10a is in the forward rotation state, as shown in FIG. 4A, the comparator 31a outputs the first rotation detection signal Vs11 having the same pulse train as the rotation detection signal Vs1, and the comparator 32a is low. The second rotation detection signal Vs12 maintained at the level is output. On the other hand, if the rotor 10a is in the reverse rotation state, as shown in FIG. 4 (B), the comparator 31a performs the first rotation consisting of a pulse train excluding the narrow pulse at the rise and fall of the rotation detection signal Vs1. The detection signal Vs11 is output, and the comparator 32a outputs the second rotation detection signal Vs12 consisting only of the narrow pulse train. These first and second rotation detection signals Vs11 and Vs12 are supplied to the microcomputer 40.

  Comparators 31b and 32b, comparators 31c and 32c, and comparators 31d and 32d are connected to the sensor unit 20b, the sensor unit 20b, and the sensor unit 20c, respectively. These comparators 31b, 32b, comparators 31c, 32c and comparators 31d, 32d are similar to the first and second rotation detection signals Vs11, Vs12 as shown in FIGS. Based on the rotation detection signals Vs2, Vs3, Vs4 from 20b, 20c, 20d, the first and second rotation detection signals Vs21, Vs22, the first and second rotation detection signals Vs31, Vs32, and the first and second. The rotation detection signals Vs41 and Vs42 are output to the microcomputer 40, respectively.

  The first and second rotation detection signals Vs11, Vs12, Vs21, Vs22, Vs31, Vs32, Vs41, and Vs42 are also supplied to the rotation direction detection unit 50. The rotation direction detection unit 50 includes four rotation direction detection circuits respectively corresponding to the sensor units 20a to 20d. As shown in FIG. 5, each rotation direction detection circuit includes R-S type flip-flop circuits 51 to 54, NOR circuits 55 to 59, and inverter circuits 61 and 62, and first and second rotation detection signals Vs11, Vs12 (or the first and second rotation detection signals Vs21 and Vs22, the first and second rotation detection signals Vs31 and Vs32, the first and second rotation detection signals Vs41 and Vs42) are input, and each of the rotors 10a to 10d is input. A rotation direction detection signal Dr1 (or Dr2 to Dr4) representing the rotation direction is output to the microcomputer 40. However, the QN outputs of the RS flip-flop circuits 51 to 54 indicate the inverted output of the Q output.

  In each rotation direction detection circuit, the rotors 10a to 10d are in the normal rotation state, and the first and second rotation detection signals Vs11, Vs12, Vs21, Vs22, Vs31, as shown in FIG. When Vs32, Vs41, and Vs42 are input, the outputs I, J, and K of the RS flip-flop circuits 51 to 53 are kept at a low level as shown in FIG. The rotation direction detection signals Dr1 to Dr4 output from the type flip-flop circuit 54 are also kept at a low level. On the other hand, when the rotors 10a to 10d are in the reverse rotation state and the first and second rotation detection signals Vs11, Vs12, Vs21, Vs22, Vs31, Vs32, Vs41, and Vs42 as shown in FIG. In this case, the outputs I, J, and K of the RS flip-flop circuits 51 to 53 become pulse train signals as shown in FIG. 6B, and the rotation direction detected from the RS flip-flop circuit 54 is detected. Each of the signals Dr1 to Dr4 is kept at a high level. However, in FIGS. 6 (A) and 6 (B), portions with dot patterns indicate indefinite portions of the rotation direction detection signals Dr1 to Dr4.

  The microcomputer 40 includes a CPU, a ROM, a RAM, a timer, and the like, and executes the programs in FIGS. 7 to 14 to detect each wheel speed and to detect an abnormality in the wheel speed. Note that the pulse detection program of FIG. 7 is repeatedly executed in a relatively short cycle (for example, several tens of μs) in cooperation with the timer. Further, the wheel speed calculation program of FIG. 8 including the programs of FIGS. 9 to 14 as a subroutine is repeatedly executed in a relatively long cycle (for example, about 6 ms) in cooperation with the timer.

  In addition to the first and second rotation detection signals Vs11, Vs12, Vs21, Vs22, Vs31, Vs32, Vs41, Vs42 and the rotation direction detection signals Dr1 to Dr4, the microcomputer 40 includes an ABS signal, a VSC signal, A TRC signal and a BAT signal are also supplied. The ABS signal is supplied from an antilock brake control device (not shown) and is a signal indicating that the vehicle is under antilock brake control. The VSC signal is supplied from a vehicle stability control device (not shown) and is a signal indicating that the vehicle is under stability control. The TRC signal is supplied from a traction control device (not shown) and is a signal indicating that the vehicle is under traction control. These ABS signal, VSC signal, and TRC signal indicate that the application or release of braking force or driving force is being controlled for each wheel according to the behavior of the vehicle, the slip state of the wheel, etc. according to the high level, The low level indicates that the control is not being performed. The BAT signal represents an abnormality (that is, a decrease) in battery voltage.

  Next, the operation of the embodiment configured as described above will be described with reference to the flowcharts of FIGS. When an ignition switch (not shown) is turned on, the microcomputer 40 starts to repeatedly execute the pulse detection program of FIG. 7 at a relatively short period, and in parallel with the execution of this program, the microcomputer of the wheel speed calculation program of FIG. Start running with a long cycle. In these programs, various processes are executed for each of the rotors 10a to 10d (left and right front and rear wheels), but the processes of the rotors 10a to 10d are common. A suffix j (j = 1 to 4) is attached to various variables corresponding to 10 to 10d, and various processes are commonly described for the rotors 10a to 10d.

  First, the pulse detection program will be described. The program starts to be executed in step S10 as shown in detail in FIG. After the start of this pulse detection program, steps S12 to S16 are executed in order to calculate a wheel speed Vxj (j = 1 to 4) described later. In step S12, it is determined whether or not the previously calculated wheel speed Vxj (j = 1 to 4) is less than a predetermined wheel speed Vr1 (for example, 65 km / h). If the previously calculated wheel speed Vxj (j = 1 to 4) is less than the predetermined wheel speed Vr1, “YES” is determined in the step S12, and the process of the step S14 is executed. On the other hand, if the previously calculated wheel speed Vxj is equal to or higher than the predetermined wheel speed Vr1, “NO” is determined in the step S12, and the process of the step S16 is executed.

  In step S14, the first rotation detection signal Vsj1 (j = 1 to 4) is input from each of the comparators 31a to 31d, and the rising of the input first rotation detection signal Vsj1 (change from low level to high level). ) And falling (change from high level to low level) are detected. When the falling edge is detected, the time is temporarily stored in cooperation with the timer. When the rising edge is detected, the time is temporarily stored in cooperation with the timer as described above. The median of the storage time at the time and the storage time at the detection of the current rising edge (low-level central time of the first rotation detection signal Vsj1) is calculated, and the calculated median is used as the current median time value Tj (n) As it is updated and memorized. As a result, the current central time value Tj (n) is updated at the time indicated by the alternate long and short dash line in FIG. 15A at each rising timing of the first rotation detection signal Vsj1, and is maintained until the next rising timing.

  Further, when the rising edge of the first rotation detection signal Vsj1 is detected, it is cleared to “0” by the process described later when the wheel speed calculation program is executed (timing shown as calculation timing in FIGS. 15A and 15B). The number of pulses PNj is counted up by “1”. Therefore, the number of pulses PNj indicates the number of pulses of the first rotation detection signal Vsj1 from the previous calculation timing.

  In step S16, the first rotation detection signal Vsj1 (j = 1 to 4) is input from each of the comparators 31a to 31d, and the fall of the input first rotation detection signal Vsj1 (from the high level to the low level). Only change). When this fall is detected, the time is updated and stored as the current time value Tj (n) in cooperation with the timer. As a result, the current time value Tj (n) is updated at the same timing (the time indicated by the alternate long and short dash line in FIG. 15B) at each falling timing of the first rotation detection signal Vsj1. Maintained until timing. Also in this case, when the falling of the first rotation detection signal Vsj1 is detected, the number of pulses PNj is counted up by “1” when the wheel speed calculation program is executed. As described above, in the process of step S16, only the fall of the first rotation detection signal Vsj1 is detected because the frequency of the process of step S16 does not become too high when the wheel speed Vxj is increased. This is because when the wheel speed Vxj becomes high, the calculation error of the wheel speed Vxj does not become so large even if the processing in step S14 is not performed.

  After the processes in steps S14 and S16, variables for use in steps S20 to S26 for setting a variable to be used in a first abnormality detection routine described later, and variables for use in a fourth abnormality detection routine to be described later are set. After the processing of steps S28 to S44, the pulse detection program is temporarily terminated in step S46. Regarding the processing of these steps S20 to S44, a wheel speed calculation program executed in parallel with this pulse detection program will be described as will be described later.

As described above, the wheel speed calculation program is executed at a period longer than that of the pulse detection program (for example, 6 ms), that is, at each timing corresponding to the calculation timing of FIGS. 15A and 15B. Execution is started in step S50 of FIG. After the execution of the wheel speed calculation program is started, the wheel speed Vxj (j = 1 to 4) is calculated by the processing of steps S52 to S56. In step S52, the time ΔTj used for calculating the wheel speed Vxj is calculated by executing the calculation of the following equation (1).
ΔTj = Tj (n) −Tj (n−1) (where j = 1 to 4)

  In Equation 1, Tj (n) is updated by the pulse detection program of FIG. 7 immediately before the execution of the wheel speed calculation program, and the previously calculated wheel speed Vxj is less than the predetermined wheel speed Vr1. If there is, it is the current central time set by the process of step S14. If the previously calculated wheel speed Vxj is equal to or higher than the predetermined wheel speed Vr1, it is the falling timing time set by the process of step S16. Tj (n-1) is updated to Tj (n) at the end of the calculation of the wheel speed Vxj by the process of step S56, and represents the central time or the falling timing time immediately before the previous calculation timing. Therefore, if the previously calculated wheel speed Vxj is less than the predetermined wheel speed Vr1, the time ΔTj calculated by the above equation 1 is equal to the central time (Tj immediately before the previous calculation timing) as shown in FIG. It represents the elapsed time from (n-1) = (t1 + t2) / 2) to the central time (Tj (n) = (t3 + t4) / 2) immediately before the current calculation timing. If the previously calculated wheel speed Vxj is equal to or higher than the predetermined wheel speed Vr1, the time ΔTj is the falling timing (Tj (n−1)) immediately before the previous calculation timing, as shown in FIG. Represents the elapsed time from the falling timing (Tj (n)) immediately before the current calculation timing.

After the process of step S52, in step S54, the wheel speed Vxj is calculated by executing the calculation of the following equation 2 using the calculated time ΔTj.
Vxj = K · PNj / ΔTj (where j = 1 to 4)

  In Equation 2, PNj is cleared to “0” by the process of step S56 at the end of the calculation of the wheel speed Vxj as described above, and is counted up by the processes of steps S14 and S16. Therefore, if the previously calculated wheel speed Vxj is less than the predetermined wheel speed Vr1, the number of pulses PNj is obtained from the central time Tj (n-1) immediately before the previous calculation timing, as shown in FIG. This represents the number of pulses of the first rotation detection signal Vsj1 up to the central time Tj (n) immediately before the current calculation timing. If the previously calculated wheel speed Vxj is equal to or higher than the predetermined wheel speed Vr1, the number of pulses PNj is the falling timing Tj (n-1) immediately before the previous calculation timing, as shown in FIG. To the number of pulses of the first rotation detection signal Vsj1 from the current calculation timing to the falling timing Tj (n). Furthermore, K is a constant determined by the number of teeth of the rotors 10a to 10d, the diameter of the wheel (tire), and the like. As a result, the wheel speed Vxj is calculated at each calculation timing (execution of the wheel speed calculation program) according to the formula 2, and sequentially updated.

  After the processing in steps S52 to S56, in step S58, the maximum wheel speed Vmax = MAX (Vx1, Vx2, Vx3, Vx4) and the minimum of the wheel speeds Vx1, Vx2, Vx3, Vx4 of the left and right front and rear wheels. Wheel speed Vmin = MIN (Vx1, Vx2, Vx3, Vx4) is calculated. Next, in step S60, rotation direction detection signals Dr1 to Dr4 are input from the rotation direction detector 50. After the processing of step S60, first to fourth abnormality detection routines for detecting abnormality of the sensor units 20a to 20d, the comparators 31a to 31d, 32a to 32d, and the rotation direction detection unit 50 in steps S62 to S68, respectively. Execute.

  In the first abnormality detection routine, as shown in FIG. 16C, only the narrow pulse signal indicating the reverse rotation of the rotors 10a to 10d is output from the sensor units 20a to 20d as the rotation detection signal Vsj. Is detected. In the first abnormality detection routine, as shown in FIGS. 16A and 16B, when the rotation detection signal Vsj returns to normal, the return from the first abnormality state is detected. Before describing the first abnormality detection routine in detail, variables set by execution of the pulse detection program of FIG. 7 and used in the first abnormality detection routine will be described.

  In step S18 of the pulse detection program of FIG. 7, the first rotation detection signal Vsj1 (j = 1 to 4) is input, and the high level time of the first rotation detection signal Vsj1 is cooperated with the built-in timer. HTj is measured sequentially for each pulse. That is, the rise and fall of the first rotation detection signal Vsj1 are detected, and the time from the rise timing to the fall timing is sequentially measured.

  In step S20, it is determined whether the measured high level time HTj of the first rotation detection signal Vsj1 is equal to or less than a predetermined time value TM00. The predetermined time value TM00 is set to about 200 μs, which is larger than at least a pulse signal width (for example, 150 μs) representing the reverse rotation of the rotors 10a to 10d and corresponds to 290 km / h or more in terms of wheel speed. The high-level time HTj of the first rotation detection signal Vsj1 is a value that cannot be normal vehicle travel. That is, as shown in FIGS. 16A and 16B, if the rotation detection signal Vsj is normal, it should not be generated. Accordingly, the fact that the high level time HTj is equal to or less than the predetermined time value TM00 indicates that only the narrow pulse signal indicating the reverse rotation of the rotors 10a to 10d is used as the rotation detection signal Vsj as shown in FIG. Means output from ~ 20d. Hereinafter, the first rotation detection signal Vsj1 including the narrow pulse signal is referred to as a duty invalid pulse.

  If the high level time HTj is larger than the predetermined time value TM00, “NO” is determined in the step S20, and the process proceeds to the step S22. If the high level time HTj is equal to or less than the predetermined time value TM00, “YES” is determined in step S20, the abnormal pulse flag ERPj is set to “1” in step S24, and the process proceeds to step S28. The abnormal pulse flag ERPj is cleared to “0” at the end of execution of a first abnormality detection routine described later. Therefore, the abnormal pulse flag ERPj is set to “1” when there is even one duty invalid pulse from the previous execution of the first abnormality detection routine to the execution of the current first abnormality detection routine. When there is no duty invalid pulse, it is set to “0”.

  In step S22, it is determined whether the high level time HTj is equal to or greater than a predetermined time value TM01. The predetermined time value TM01 is sufficiently larger than the predetermined time value TM00, and is set to 500 μs, for example. Therefore, the high level time HTj being equal to or greater than the predetermined time value TM01 means that the normal rotation detection signal Vsj is output from the sensor units 20a to 20d, as shown in FIGS. To do. Hereinafter, the first rotation detection signal Vsj1 having a pulse width having a high level time HTj of 500 μs or more is referred to as a duty effective pulse.

  If the high level time HTj is less than the predetermined time value TM01, “NO” is determined in the step S22, and the process proceeds to a step S28. If the high level time HTj is equal to or greater than the predetermined time value TM01, “YES” is determined in step S22, the normal pulse flag CRPj is set to “1” in step S26, and the process proceeds to step S28. The normal pulse flag CRPj is also cleared to “0” at the end of execution of a first abnormality detection routine described later. Therefore, the normal pulse flag CRPj is set to “1” when there is even one duty effective pulse from the previous execution of the first abnormality detection routine to the execution of the current first abnormality detection routine. This is set to “0” when there is no duty effective pulse.

  Next, the first abnormality detection routine in step S62 in FIG. 8 will be described. The first abnormality detection routine is shown in detail in FIG. 9, and its execution is started in step S100 in FIG. 9. In step S102, the calculated wheel speed Vxj is set to a predetermined wheel speed Vr1 (for example, 65 km). / h) is determined. If the wheel speed Vxj is less than a predetermined wheel speed Vr1 (for example, 65 km / h), “YES” is determined in step S102, and it is determined whether or not the abnormal pulse flag ERPj is “1” in step S104. To do. If the abnormal pulse flag ERPj is “1”, “YES” is determined in step S104, and the first error flag ER1j is set to “1” in step S106. The first error flag ER1j represents a detection state of the first abnormality of the sensor unit corresponding to the variable j among the sensor units 20a to 20d by “1”. Therefore, if the wheel speed Vxj is less than the predetermined wheel speed Vr1, and there is a duty invalid pulse from the previous execution of the first abnormality detection routine to the execution of the current first abnormality detection routine, the sensor units 20a to 20d, etc. The first abnormality is detected.

  On the other hand, if there is no duty invalid pulse from the previous execution of the first abnormality detection routine to the current execution of the first abnormality detection routine and the abnormality pulse flag ERPj is “0”, “NO” is determined in step S104. ”And the process proceeds to step S108. Thereby, in this case, the first abnormality such as the sensor units 20a to 20d is not detected.

  Further, if the wheel speed Vxj is equal to or higher than the predetermined wheel speed Vr1, “NO” is determined in the step S102, and the process proceeds to a step S108. Therefore, in this case, the determination process in step S104 is not performed, and the first abnormality is not detected. This is to avoid erroneous detection of the first abnormality due to erroneous detection of the duty invalid pulse when the wheel speed Vxj increases. Therefore, the determination process in step S104 is a basic detection condition for the first abnormality, and the determination process in step S102 is a supplementary detection condition for avoiding erroneous detection of the first abnormality.

  After the first abnormality detection process including steps S102 to S106, it is determined in step S108 whether or not the first error flag ER1j is “1”. If the first error flag ER1j is “0”, “NO” is determined in step S108, the abnormal pulse flag ERPj and the normal pulse flag CRPj are both cleared to “0” in step S124, and the process proceeds to step S126. The first abnormality detection routine is finished. If the first error flag ER1j is set to “1”, “YES” is determined in the step S108, and the abnormality recovery detection process including the steps S110 to S122 is executed.

  In this abnormal recovery detection process, “YES” is determined in step S110 on the condition that the first abnormal recovery detection temporary flag ER1Yj is “0”, and the abnormal pulse flag ERPj is “1” in step S112. In step S114, it is determined whether the normal pulse flag CRPj is “1”. There is a duty invalid pulse between the previous execution of the first abnormality detection routine and the current execution of the first abnormality detection routine, and the abnormal pulse flag ERPj is “1”, or there is a duty effective pulse between them. If the normal pulse flag CRPj is not “0”, it is determined as “NO” in any of steps S112 and S114, the above-described clear process in step S124 is executed, and this step is performed in step S126. 1 The execution of the abnormality detection routine is terminated.

  On the other hand, there is no duty invalid pulse between the previous execution of the first abnormality detection routine and the execution of the current first abnormality detection routine, the abnormal pulse flag ERPj is “0”, and the duty is valid during the same period. If there is a pulse and the normal pulse flag CRPj is “1”, it is determined as “YES” in steps S112 and S114, and the first abnormal return detection provisional flag ER1Yj is set to “1” in step S116. To do. And the clear process of step S124 mentioned above is performed, and execution of this 1st abnormality detection routine is complete | finished in step S126.

  In this way, when the first abnormal return detection temporary flag ER1Yj is set to “1”, it is determined as “NO” in the next step S110, and the processes of steps S118 to S122 are executed. In this case, the duty is invalid during the period from the previous execution of the first abnormality detection routine to the execution of the current first abnormality detection routine, that is, in the next determination section in which the first abnormality return detection temporary flag ER1Yj is set to “1”. If there is no pulse and the abnormal pulse flag ERPj is “0”, “YES” is determined in step S118, and the first error flag ER1j is returned to “0” in step S120. Then, in step S122, the first abnormality return detection temporary flag ER1Yj is returned to “0”, the above-described clear processing in step S124 is executed, and in step S126, the execution of the first abnormality detection routine is ended.

  By processing in these steps S110 to 122, there is no duty invalid pulse during a predetermined determination period (for example, 6 ms) and there is a duty valid pulse, and there is no duty invalid pulse during the subsequent determination period. On the condition, the return from the first abnormality of the sensor unit corresponding to the variable j among the sensor units 20a to 20d is detected. Note that the determination processing in steps S112 and 114 is a basic condition for returning from the first abnormal state to the normal state, and the determination processing in step S118 is supplementary for avoiding erroneous detection of return to the normal state. It is a condition.

  If there is a duty invalid pulse during the next determination cycle (for example, 6 ms) in which the first abnormal return detection temporary flag ER1Yj is set to “1”, “NO”, that is, an abnormal pulse in step S118. After determining that the flag ERPj is not “0” and returning the first abnormal return detection temporary flag ER1Yj to “0” in step S122, the process proceeds to step S124 and thereafter. Therefore, in this case, detection of the return from the first abnormal state to the normal state is performed again from the determination processing in steps S112 and S114.

  In the first abnormality detection process, the abnormality may be determined only under the condition that the duty invalid pulse exists during a predetermined determination period. In this case, the determination process in step S102 of FIG. 9 may be omitted, and if “YES” is determined in step S104, the first error flag ER1j may be set to “1” in step S106. .

  Further, in the first abnormal recovery detection process, only the condition that the duty invalid pulse does not exist during the predetermined determination period and the duty effective pulse exists, or the duty invalid pulse does not exist during the predetermined determination period. The return of abnormality detection may be determined only by conditions. In this case, instead of the processing of steps S110 to S122, the first error flag ER1j is returned to “0” when both are determined to be “YES” by the determination processing of steps S112 and S114, or by the determination processing of step S118. When it is determined “YES”, the first error flag ER1j may be returned to “0”.

  Next, the second abnormality detection routine in step S64 in FIG. 8 will be described. This second abnormality detection routine detects an abnormality (hereinafter referred to as a second abnormality) that the rotation direction of each wheel is different from the rotation direction of the other three wheels, and detects the recovery of the second abnormality. .

  The second abnormality detection routine is shown in detail in FIGS. 10 and 11. The microcomputer 40 starts executing the second abnormality detection routine in step S200, and in step S202, the second error flag ER2j. Is determined to be “0”. If the second error flag ER2j is “0”, “YES” is determined in step S202, the second abnormality detection process including steps S204 to S228 is executed, and the second abnormality is detected in step S254. End the detection routine execution. On the other hand, if the second error flag ER2j is “1”, it is determined as “NO” in step S202, and the detection processing for returning from the second abnormal state to steps S230 to S252 is executed. In step S254, the execution of the second abnormality detection routine is terminated.

  In the abnormality detection process including steps S204 to S228, the rotation direction detection signals Dr1 to Dr4 input by the process of step S60 of FIG. 8 are used in step S204, and one of the rotors 10a to 10d is related. It is determined whether only the rotation direction of one wheel is different from the rotation direction of the other three wheels, depending on whether only the rotation direction detection signal Drj (j is any one of 1 to 4) is different from the other three rotation direction detection signals. To do. The determination process in step S204 is a basic condition for detecting the second abnormality.

  In step S206, it is determined whether the minimum wheel speed Vmin calculated by the process in step S58 of FIG. 8 is higher than a predetermined wheel speed Vr2 (for example, 30 km / h). This determination condition is supplemented to avoid erroneous determination of the second abnormality due to the vehicle body swinging back and forth when the vehicle is almost stopped and only the rotation direction of one wheel is different from the rotation direction of the other three wheels. Condition. In step S208, it is determined whether the difference Vmax−Vmin between the maximum wheel speed Vmax and the minimum wheel speed Vmin calculated by the process in step S58 of FIG. 8 is less than a predetermined wheel speed Vr3 (for example, 2 km / h). . This determination condition avoids an erroneous determination of the second abnormality due to the vehicle being in a turning state (not in a straight traveling state) and only the rotation direction of one wheel being different from the rotation direction of the other three wheels. It is a supplementary condition for.

  In step S210, an ABS signal, a VSC signal, and a TRC signal are input to determine whether or not all these signals are at a low level, that is, whether braking force or driving force is being applied to or released from each wheel is not being controlled. Determine. This determination condition is also due to the fact that the braking direction or driving force is applied and released for each wheel according to the slip state of the wheel, and as a result, only the rotational direction of one wheel is different from the rotational direction of the other three wheels. This is a supplementary condition for avoiding erroneous determination of the second abnormality.

  Unless all the determination conditions of these steps S204 to S210 are satisfied, “NO” is determined in any of steps S204 to S210, the count value CT1 is set to “0” in step S226, and step S228 is performed. The second abnormality detection temporary flag ER2Xj is set to “0” at step S254, and the execution of the second abnormality detection routine is terminated at step S254. This count CT1 is initially set to “0”, and measures the duration of establishment of the abnormality detection conditions in steps S204 to S210 by measuring the number of executions of the second abnormality detection routine. The second abnormality detection provisional flag ER2Xj indicates that the second abnormality detection operation is being performed by “1”.

  On the other hand, when all the determination conditions in steps S204 to S210 are satisfied, “YES” is determined in steps S204 to S210, respectively, and whether or not the second abnormality detection provisional flag ER2Xj is “0” is determined in step S212. . If the second abnormality detection temporary flag ER2Xj is “0”, “YES” is determined in step S212, the count value CT1 is set to “0” in step S214, and the second abnormality detection temporary flag is determined in step S216. The flag ER2Xj is set to “1”, and the execution of the second abnormality detection routine is ended in step S254.

  If all the determination conditions of steps S204 to S210 continue to be satisfied, the second abnormality detection temporary flag ER2Xj is kept at “1”, so that it is determined as “NO” in step S212, and step S218. , S220. In step S218, “1” is added to the count value CT1. In step S220, it is determined whether the count value CT1 is equal to or greater than a predetermined value CT10 (eg, “17”). If it is not long after the count value CT1 is set to “0” by the process of step S214, the determination of “NO” is continued in step S220, and the execution of the second abnormality detection routine is ended in step S254. To do. In this state, the count value CT1 is incremented by “1” every time the second abnormality detection routine is executed by the process of step S218.

  Further, if all the determination conditions in steps S204 to S210 continue to be satisfied, the count CT1 becomes equal to or greater than the predetermined value CT10. Therefore, “YES” is determined in step S220, and the second error flag ER2j is set to “ Set to 1 ”. The second error flag ER2j represents a detection state of the second abnormality of the sensor unit corresponding to the variable j among the sensor units 20a to 20d by “1”, and the processing of steps S204 to S228 A second abnormality such as the sensor units 20a to 20d is detected. Further, after the process of step S222, the second abnormality detection temporary flag ER2Xj is returned to “0” in step S224, and the execution of the second abnormality detection routine is ended in step S254.

  In this way, after the second error flag ER2j is set to “1”, it is determined “NO” in step S202, and the second abnormality return detection process including steps S230 to S252 is executed. It becomes like this.

  In the abnormal recovery detection process including steps S230 to S252, one of the rotors 10a to 10d is used by using the rotation direction detection signals Dr1 to Dr4 input by the process of step S60 in FIG. Whether the rotation direction of one wheel is the same as the rotation direction of the other three wheels depending on whether the rotation direction detection signal Drj (j is any one of 1 to 4) is the same as the other rotation direction detection signal judge. The determination process in step S230 is a basic condition for detecting an abnormal return.

  In steps S232 and S234, the minimum wheel speed Vmin is greater than a predetermined wheel speed Vr2 (for example, 30 km / h) or the maximum wheel speed Vmax and the minimum wheel speed Vmin, as in the supplementary conditions of steps S206 and S208. It is determined whether the difference Vmax−Vmin is less than a predetermined wheel speed Vr3 (for example, 2 km / h).

  Unless all the determination conditions of these steps S230 to S234 are satisfied, it is determined as “NO” in any of steps S230 to S234, and the count value CT2 is set to “0” in step S250. In step S252, the second abnormality return detection temporary flag ER2Yj is set to “0”, and in step S254, the execution of the second abnormality detection routine is ended. This count value CT2 is also set to “0” in the initial stage, and measures the duration of establishment of the abnormal return detection condition in steps S230 to S234 by measuring the number of executions of this second abnormality detection routine. is there. The second abnormal return detection temporary flag ER2Yj indicates that the second abnormal return detection operation is being performed by “1”.

  On the other hand, when all the determination conditions in steps S230 to S234 are satisfied, it is determined as “YES” in steps S230 to S234, respectively, and in step S236, it is determined whether the second abnormal return detection provisional flag ER2Yj is “0”. To do. If the second abnormal return detection temporary flag ER2Yj is “0”, “YES” is determined in step S236, the count value CT2 is set to “0” in step S238, and the second abnormal return is determined in step S240. The temporary detection flag ER2Yj is set to “1”, and the execution of the second abnormality detection routine is terminated in step S254.

  If all the determination conditions in steps S230 to S254 continue to be satisfied, the second abnormal return detection temporary flag ER2Yj is kept at “1”, so that it is determined as “NO” in step S236. Proceed to S242 and S244. In step S242, “1” is added to the count value CT2. In step S244, it is determined whether the count value CT1 is equal to or greater than a predetermined value CT20 (eg, “83”). If it is not long after the count value CT2 is set to “0” by the process of step S240, the determination of “NO” is continued in step S244, and the execution of the second abnormality detection routine is ended in step S254. To do. In this state, the count value CT2 is incremented by “1” every time the second abnormality detection routine is executed by the process of step S242.

  Further, if all the determination conditions in steps S230 to S234 are satisfied, the count value CT2 becomes equal to or greater than the predetermined value CT20. Therefore, “YES” is determined in step S244, and the second error flag ER2j is set in step S246. Return to “0”. Thereby, the return from the second abnormal state such as the sensor units 20a to 20d to the normal state is detected. Further, after the process of step S246, the second abnormality return detection temporary flag ER2Yj is returned to “0” in step S248, and the execution of the second abnormality detection routine is ended in step S254.

  In the second abnormality detection process, the abnormality is determined by the determination process in steps S204 to S210 and S220. However, the determination process in steps S206 to S210 and S2220 is appropriately performed in one or more steps. The determination process may be omitted. In addition, the abnormality recovery is determined by the determination processing in steps S230 to S234 and S244. However, regarding the determination processing in steps S232, S234, and S244, the determination processing in one or more steps is appropriately omitted. Also good.

  Next, the third abnormality detection routine in step S66 of FIG. 8 will be described. The third abnormality detection routine detects an abnormality (hereinafter referred to as a third abnormality) that the wheel speed is too large when the vehicle is moving backward, and detects the recovery of the third abnormality.

  This third abnormality detection routine is shown in detail in FIGS. 12 and 13, and the microcomputer 40 starts executing the third abnormality detection routine in step S300, and in step S302, the third error flag ER3j. Is determined to be “0”. If the third error flag ER3j is “0”, “YES” is determined in Step S302, the third abnormality detection process including Steps S304 to S326 is executed, and the third abnormality is performed in Step S352. End the detection routine execution. On the other hand, if the third error flag ER3j is “1”, it is determined as “NO” in step S302, and the process of detecting the return from the third abnormal state to steps S328 to S350 is executed. In step S352, the execution of the third abnormality detection routine is terminated.

  In the abnormality detection process including steps S304 to S326, the rotation direction detection signal Drj is selected from the rotors 10a to 10d using the rotation direction detection signal Drj input by the process of step S60 of FIG. It is determined whether it represents the reverse direction of the corresponding rotor (wheel). In step S306, it is determined whether the wheel speed Vxj calculated by the process in step S54 of FIG. 8 is higher than a predetermined wheel speed Vr4 (for example, 100 km / h). Note that the determination processing in steps S304 and S306 is a basic condition for detecting the third abnormal state.

  In step S308, it is determined whether the minimum wheel speed Vmin calculated by the process in step S58 of FIG. 8 is greater than a predetermined wheel speed Vr5 (for example, 30 km / h). This determination condition is a supplementary condition for avoiding an erroneous determination of the third abnormality due to the rotation of the other wheels being stopped and only some of the wheels including the corresponding wheels are idling.

  Unless all the determination conditions of these steps S304 to S308 are satisfied, “NO” is determined in any of steps S304 to S308, the count value CT3 is set to “0” in step S324, and step S326. The third abnormality detection provisional flag ER3Xj is set to “0”, and the execution of the third abnormality detection routine is ended in step S352. This count CT3 is also set to “0” in the initial stage, and measures the number of times this third abnormality detection routine is executed, thereby measuring the duration of establishment of the abnormality detection conditions in steps S304 to S308. The third abnormality detection temporary flag ER3Xj indicates that the third abnormality detection operation is being performed by “1”.

  On the other hand, when all the determination conditions of steps S304 to S308 are satisfied, “YES” is determined in steps S304 to S308, respectively, and it is determined whether or not the third abnormality detection provisional flag ER3Xj is “0” in step S310. . If the third abnormality detection temporary flag ER3Xj is “0”, “YES” is determined in step S310, the count value CT3 is set to “0” in step S312, and the third abnormality detection temporary is determined in step S314. The flag ER3Xj is set to “1”, and the execution of the third abnormality detection routine is ended in step S352.

  If all the determination conditions in steps S304 to S308 continue to be satisfied, the third abnormality detection temporary flag ER3Xj is kept at “1”, so that it is determined as “NO” in step S310, and step S316. , 318. In step S316, “1” is added to the count value CT3. In step S318, it is determined whether the count value CT3 is equal to or greater than a predetermined value CT30 (eg, “17”). If it is not long after the count value CT3 is set to “0” by the process of step S312, the determination of “NO” is continued in step S318, and the execution of the third abnormality detection routine is ended in step S352. To do. In this state, the count value CT3 is incremented by “1” every time the third abnormality detection routine is executed by the process of step S316.

  Further, if all the determination conditions of steps S304 to S308 continue to be satisfied, the count value CT3 becomes equal to or greater than the predetermined value CT30. Therefore, “YES” is determined in step S318, and the third error flag ER3j is set in step S320. Set to “1”. The third error flag ER3j represents a detection state of the third abnormality of the sensor unit corresponding to the variable j among the sensor units 20a to 20d by “1”, and the processing of steps S304 to S318 A third abnormality such as the sensor units 20a to 20d is detected. Further, after the process of step S320, the third abnormality detection temporary flag ER3Xj is returned to “0” in step S322, and the execution of the third abnormality detection routine is ended in step S352.

  In this way, after the third error flag ER3j is set to “1”, it is determined as “NO” in step S302, and the third abnormality return detection process including steps S328 to S350 is executed. It becomes like this.

  In the abnormal recovery detection process including steps S328 to S350, the rotation direction detection of all the rotors 10a to 10d (wheels) is performed using the rotation direction detection signals Dr1 to Dr4 input by the process of step S60 in step S328. It is determined whether the rotation directions of the four wheels are the same depending on whether the signals Dr1 to Dr4 are the same. Note that the determination process in step S328 is a basic condition for detecting an abnormal return.

  In step S330, it is determined whether the minimum wheel speed Vmin calculated by the process in step S58 of FIG. 8 is greater than a predetermined wheel speed Vr6 (for example, 10 km / h). In step S332, it is determined whether the difference Vmax−Vmin between the maximum wheel speed Vmax and the minimum wheel speed Vmin calculated by the process in step S58 of FIG. 8 is less than a predetermined wheel speed Vr7 (for example, 2 km / h). judge. The determination conditions of these steps S330 and S332 are supplementary conditions for determining that the vehicle is in a straight traveling state, whereby the return of the third abnormality in step S328 when the vehicle is not traveling straight ahead. Misdetection of detection is avoided.

  Then, unless all the determination conditions of these steps S328 to S332 are satisfied, “NO” is determined in any of steps S328 to S332, and the count value CT4 is set to “0” in step S348. In step S350, the third abnormality return detection temporary flag ER3Yj is set to “0”, and in step S352, the execution of the third abnormality detection routine is ended. This count value CT4 is also set to “0” in the initial stage, and measures the duration of establishment of the abnormal return detection condition in steps S328 to S332 by measuring the number of executions of this third abnormality detection routine. is there. The third abnormal recovery detection temporary flag ER3Yj indicates that the recovery operation from the third abnormality is being performed by “1”.

  On the other hand, when all the determination conditions of steps S328 to S332 are satisfied, “YES” is determined in steps S328 to S332, respectively, and it is determined whether or not the third abnormal return detection provisional flag ER3Yj is “0” in step S334. To do. If third abnormal return detection temporary flag ER3Yj is “0”, “YES” is determined in step S334, count CT4 is set to “0” in step S336, and third abnormal return detection is detected in step S338. The temporary flag ER3Yj is set to “1”, and the execution of the third abnormality detection routine is ended in step S352.

  If all the determination conditions of steps S328 to S332 continue to be satisfied, the third abnormal return detection temporary flag ER3Yj is kept at “1”, so that it is determined as “NO” in step S334, and the step Proceed to S340, 342. In step S340, “1” is added to the count value CT4. In step S342, it is determined whether the count value CT4 is equal to or greater than a predetermined value CT40 (eg, “83”). If it is not long after the count value CT4 is set to “0” by the process of step S336, the determination of “NO” is continued in step S342, and the execution of the second abnormality detection routine is ended in step S352. To do. In this state, the count value CT4 is incremented by “1” every time the third abnormality detection routine is executed by the process of step S340.

  Further, if all the determination conditions of steps S328 to S332 continue to be satisfied, the count value CT4 becomes equal to or greater than the predetermined value CT40. Therefore, “YES” is determined in step S342, and the third error flag ER3j is set in step S344. Return to “0”. Thereby, the return from the third abnormal state such as the sensor units 20a to 20d to the normal state is detected. Further, after the process of step S344, the third abnormality return detection temporary flag ER3Yj is returned to “0” in step S346, and the execution of the third abnormality detection routine is ended in step S352.

  In the third abnormality detection process, the abnormality is determined by the determination process in steps S304 to S308 and S318. However, the determination process in any one of steps S308 and S318 may be omitted. In addition, the return of the abnormality is determined by the determination process in steps S328 to S332 and S342. However, regarding the determination process in steps S330, S332, and S342, one or more determination processes may be omitted. Good.

  Next, the fourth abnormality detection routine in step S68 of FIG. 8 will be described. In the fourth abnormality detection routine, the rotation detection signals Vsj (j = 1 to 4) from the sensor units 20a to 20d repeat frequent forward and reverse rotations of the rotors 10a to 10d as shown in FIG. This is to detect an abnormality (hereinafter referred to as a fourth abnormality) composed of a pulse train signal. Before describing the fourth abnormality detection routine in detail, variables that are set by execution of the pulse detection program of FIG. 7 and used in the fourth abnormality detection routine will be described.

  In step S28 of the pulse detection program in FIG. 7, the first rotation detection signal Vsj1 is input, and it is determined whether the rotation detection signal Vsj1 has been at the previous low level and has now changed to the high level. It is determined whether it is the rising timing of Vsj. In this case, if the rotation detection signal Vsj is not the rising timing, “NO” is determined in step S28, and the execution of the pulse detection program is ended in step S46.

  On the other hand, if the rotation detection signal Vsj is the rising timing, “YES” is determined in step S28, and “1” is added to the pulse count value PACTj in step S30. This pulse count value PACTj represents the number of times the rotation detection signal Vsj has changed from the low level to the high level (from the V0 level to the V1 or V2 level), that is, the number of wide pulses of the rotation detection signal Vsj. 0 "is set.

  After the processing in step S30, in step S32, the second rotation detection signal Vsj2 is input to determine whether the rotation detection signal Vsj2 is at a high level (in other words, whether a reverse pulse signal exists). Thus, it is determined whether the rotation detection signal Vsj represents forward rotation (corresponding to forward movement of the vehicle) or reverse rotation (corresponding to backward movement of the vehicle) of the corresponding rotor.

  Then, if the second rotation detection signal Vsj2 is at a low level and the rotation detection signal Vsj represents the forward movement state of the wheel, “YES” is determined in step S32, and the process proceeds to step S34 and subsequent steps. In step S34, it is determined whether or not the reverse rotation flag REVFj is “1”. The reverse rotation flag REVFj indicates the reverse rotation of the corresponding rotor (wheel) by “1”. If the previous rotation detection signal Vsj represents the reverse state of the wheel and the reverse rotation flag REVFj is “1”, “YES” is determined in step S34, and the change count value CGCTj is set to “1” in step S36. ”Is added, the reverse rotation flag REVFj is changed to“ 0 ”in step S38, and the execution of the pulse detection program is terminated in step S46. This change count value CGCTj represents the number of changes in the rotation detection signal Vsj from the forward state to the reverse state and the number of changes from the reverse state to the forward state, and is initially set to “0”. Further, if the previous rotation detection signal Vsj represents the forward movement state of the wheel and the reverse rotation flag REVFj is “0”, it is determined as “NO” in step S34, and the pulse detection program of this pulse detection program is determined in step S46. End execution.

  On the other hand, if the second rotation detection signal Vsj2 is at the high level and the rotation detection signal Vsj indicates the reverse state of the wheel at the time of the determination in step S32, “NO” is determined in step S32, and step S40. Proceed to the following. In step S40, it is determined whether the reverse rotation flag REVFj is “0”. If the previous rotation detection signal Vsj represents the forward state of the wheel and the reverse rotation flag REVFj is “0”, “YES” is determined in step S40, and the change count value CGCTj is determined in step S42. "1" is added, the reverse rotation flag REVFj is changed to "1" in step S44, and the execution of this pulse detection program is ended in step S46. If the previous rotation detection signal Vsj represents the reverse state of the wheel and the reverse rotation flag REVFj is “1”, “NO” is determined in step S40, and this pulse detection program is determined in step S46. End execution.

  Next, the fourth abnormality detection routine in step S68 of FIG. 8 will be specifically described. The fourth abnormality detection routine is shown in detail in FIG. 14, and its execution is started in step S400. After the execution of the fourth abnormality detection routine is started, it is determined in step S402 whether the counting flag CNTFj is “0”. The counting flag CNTFj is set to “1” in step S406 described later, and is initially set to “0”. Therefore, in step S402, it is first determined “YES”, and the process proceeds to step S404.

  In step S404, it is determined whether or not the change count value CGCTj representing the number of forward / backward changes is “1” or more. That is, it is determined whether or not the rotation detection signal Vsj representing the forward / reverse change of the vehicle is output between the execution of the previous fourth abnormality detection routine and the execution of the current fourth abnormality detection routine. If there is no forward / backward change between the previous execution of the fourth abnormality detection routine and the current execution of the fourth abnormality detection routine, “NO”, that is, the change count value CGCTj is not “1” or more in step S404. In step S408, the pulse count value PUCTj is cleared to “0”, and in step S410, the change count value CGCTj is also cleared to “0”. In step S428, the fourth abnormality detection routine is executed. End execution.

  Therefore, the rotation during the execution of the fourth abnormality detection routine is performed by the processing of steps S28 to S44 of the pulse detection program of FIG. 7 until the rotation detection signal Vsj representing the forward / reverse change of the vehicle is detected. The wide number of pulses (pulse count value PUCTj) and the number of forward / backward changes (change count value CGCTj) of the detection signal Vsj are continuously measured. If a rotation detection signal Vsj representing a change in forward / reverse of the vehicle is detected between the execution of the fourth abnormality detection routine of the previous time and the execution of the fourth abnormality detection routine of the current time, in step S404, “ YES, that is, it is determined that the change count value CGCTj is “1” or more, and the counting flag CNTFj is set to “1” in step S406.

  When the counting flag CNTFj is set to “1” in this way, “NO” is determined in step S402 of the fourth abnormality detection routine after the next time, and the processing of steps S412 to 426 is executed. become. In step S412, it is determined whether or not the pulse count value PUCTj is greater than or equal to a predetermined value PUCT0 (eg, “50”). If the pulse count value PUCTj is less than the predetermined value CT0, “NO” is determined in step S412, and the execution of the fourth abnormality detection routine is ended in step S428.

  On the other hand, in this state, the pulse count value PUCTj and the change count value CGCTj are not cleared to “0” by the processing in steps S408 and S410. Therefore, the processing in steps S28 to S44 of the pulse detection program of FIG. 7 changes the number of wide pulses (pulse count value PUCTC) and forward / reverse of the rotation detection signal Vsj from the previous execution of the fourth abnormality detection routine. The number of times (change count value CGCTj) is continuously counted up.

  If the pulse count value PUCTj is less than the predetermined value PUCTO, it is determined as “NO” in step S412, and therefore the pulse count value PACTj and the change count value CGCTj are continuously counted up by the pulse detection program. As a result, when the pulse count value PUCTj increases and becomes equal to or greater than the predetermined value PUCTO, “YES” is determined in the step S412, and the determination processes of the steps S414 to S418 are executed.

  In step S414, it is determined whether or not the ratio CGCTj / PUCTj of the change count value CGCTj to the pulse count value PUCTj is equal to or greater than “0.7”. This ratio CGCTj / PUCTj represents the repetition frequency of normal rotation and reverse rotation of the rotors 10a to 10d based on the rotation detection signal Vsj (j = 1 to 4). It shows that the repetition frequency increases. The determination process in step S414 is a basic condition for detecting the fourth abnormality.

  In step S416, it is determined whether the wheel speed Vxj calculated in step S54 of FIG. 8 is higher than a predetermined wheel speed Vr8 (for example, 10 km / h). The process of step S416 is a supplementary detection condition for avoiding erroneous detection of the fourth abnormality based on the fact that the rotors 10a to 10d hardly rotate. In step S418, the battery signal BT is input to determine whether there is a battery abnormality (the battery voltage is low). The determination process in step S418 is a supplementary detection condition for avoiding erroneous detection of the fourth abnormality due to battery abnormality (low battery voltage).

  If all of these conditions are not satisfied, “NO” is determined in any one of the steps S414 to S418, and in steps S422 to S426, the pulse count value PUCTj, the change count value CGCTj, and The counting flag CNTFj is cleared to “0”, and the execution of the fourth abnormality detection routine is terminated in step S428. In this case, the pre-processing for calculating the ratio CGCTj / PUCTj by the processing of steps S28 to S44 and steps S402 to S412 of the pulse detection program of FIG.

  On the other hand, if all the determination conditions are satisfied, “YES” is determined in steps S412 to S418, the fourth error flag ER4j is set to “1” in step S420, and the fourth abnormality is determined in step S428. End the detection routine execution. The fourth error flag ER4j represents a detection state of the fourth abnormality of the sensor unit corresponding to the variable j among the sensor units 20a to 20d by “1”. A fourth anomaly such as 20d is detected. When the fourth abnormality is detected, the return of the abnormality is not detected, and thereafter, the fourth error flag ER4j is maintained at “1”.

  In the fourth abnormality detection, the determination process in steps S416 and S418, which is a supplementary condition among steps S414 to S418, may be omitted. In addition, the determination process of the rotation direction of the rotor based on the rotation detection signal Vsj in step S32 is merely an example. Instead of or in addition to this, the second rotation detection signal Vsj2 at the time of the fall of the rotation detection signal Vsj is shown. The determination process of the rotation direction of the rotor based on the rotation detection signal Vsj may be performed based on the high level or the low level.

  Further, in the fourth abnormality detection, when the pulse count value PUCTj becomes equal to or greater than the predetermined value PUCTO, the ratio CGCTj / PUTj of the change count value CGCTj to the pulse count value PACTj is equal to or greater than “0.7”. As a condition, the fourth abnormality was detected. However, instead of this, the ratio CGCTj / PUCTj in a predetermined section, such as the ratio CGCTj / PUCTj at a predetermined time and the ratio CGCTj / PUCTj while a wheel (vehicle) travels a predetermined distance, You may make it detect a 4th abnormality on condition that it is more than "0.7". Also, regarding the value “0.7” compared with the ratio CGCTj / PUCTj, another predetermined value may be adopted as long as it is a value that is somewhat large and is “1.0” or less.

  After the execution of the first to fourth abnormality detection routines, the wheel speeds Vx1 to Vx4 detected by the process of step S54 and the rotation direction input by the process of step S60 are detected in step S70 of FIG. The signals Dr1 to Dr4 and the first to fourth error flags ER1j to ER4j (j = 1 to 4) resulting from the processing of steps S62 to S68 are appropriately output to various control devices. Specifically, if the first to fourth error flags ER1j to ER4j (j = 1 to 4) are not set to “1” representing the first to fourth abnormalities, respectively, the wheel speeds Vx1 to Vx4 and the rotation direction are set. The detection signals Dr1 to Dr4 are output to various control devices and used for various controls by the control device. On the other hand, if one of the first to fourth error flags ER1j to ER4j (j = 1 to 4) is set to “1” indicating the first to fourth abnormality, it is set to “1”. The first to fourth error flags ER1j to ER4j (j = 1 to 4) are output, and the wheel speeds Vx1 to Vx4 and the rotation direction detection signals Dr1 to Dr4 corresponding to the flags are not output. In this case, a warning is given to the driver based on the first to fourth error flags ER1j to ER4j (j = 1 to 4) which are set and output to “1”, and the control modes in the various control devices are as follows. Be changed.

  In the above-described embodiment, a narrow pulse is added to the rotation detection signal Vsj (j = 1 to 4) only when the rotors 10a to 10d are reversed, so that the forward rotation and the reverse rotation of the rotors 10a to 10d are performed. It became possible to distinguish. However, instead of this, a narrow pulse is added to the rotation detection signal Vsj (j = 1 to 4) only when the rotors 10a to 10d are normally rotated, so that the forward and reverse rotations of the rotors 10a to 10d are performed. May be determined. Also in this case, the first abnormality of the rotation detection signal Vsj (j = 1 to 4) can be detected by detecting a narrow pulse in the processing of the first abnormality detection routine similar to the above.

  Moreover, in the said embodiment, the wheel speed detection process including a pulse detection process and abnormality detection was performed by the program process corresponding to the flowchart shown in FIGS. However, in implementing the present invention, a part of the program may be realized by processing by a hardware circuit.

  Furthermore, the above embodiment is an example of the present invention, and various modifications can be made without departing from the object and spirit of the present invention.

1 is an overall schematic diagram of a wheel speed detection device according to an embodiment of the present invention. It is an output waveform diagram of the rotation sensor and the waveform shaping circuit when the rotor rotates. (A) is a signal waveform diagram of each part in the sensor unit of FIG. 1 during forward rotation of the rotor, and (B) is a signal waveform diagram of each part in the sensor unit of FIG. 1 during reverse rotation of the rotor. (A) is an output waveform diagram of the sensor unit and each comparator during forward rotation of the rotor, and (B) is an output waveform diagram of the sensor unit and each comparator during reverse rotation of the rotor. It is a detailed circuit of each rotation direction detection circuit in the rotation direction detection circuit part of FIG. (A) is a signal waveform diagram of each part of the rotation direction detection circuit of FIG. 5 during forward rotation of the rotor, and (B) is a signal waveform diagram of each part of the rotation direction detection circuit of FIG. 5 during rotation of the rotor. . It is a flowchart of the pulse detection program performed with the microcomputer of FIG. It is a flowchart of the wheel speed calculation program performed with the microcomputer of FIG. It is a detailed flowchart of the 1st abnormality detection routine of FIG. FIG. 9 is a detailed flowchart showing a first half part of a second abnormality detection routine of FIG. 8. FIG. 9 is a detailed flowchart illustrating a second half of the second abnormality detection routine of FIG. 8. FIG. 9 is a detailed flowchart showing a first half part of a third abnormality detection routine of FIG. 8. FIG. 9 is a detailed flowchart showing a second half of the third abnormality detection routine of FIG. 8. It is a detailed flowchart of the 4th abnormality detection routine of FIG. (A) and (B) are time charts for explaining the operation of detecting the wheel speed Vxj based on the first rotation detection signal Vsj. (A) and (B) are waveform diagrams of normal first rotation detection signals Vsj input to the microcomputer at the time of forward rotation and reverse rotation of the rotor, respectively. (C) is an abnormal waveform of the first rotation detection signal Vsj. It is a wave form diagram which shows an example, (D) is a wave form diagram which shows the other example of abnormality of the 1st rotation detection signal Vsj.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10a-10d ... Rotor, 20a-20d ... Sensor unit, 21a, 22a ... Rotation sensor, 31a-31d, 32a-32d ... Comparator, 40 ... Microcomputer, 50 ... Rotation direction detection part.

Claims (3)

A pulse train with a cycle that shortens as the rotational speed of the rotor that rotates integrally with the wheel increases, and a rotation pulse train signal that includes a direction signal that indicates normal rotation and reverse rotation of the rotor is generated according to the rotation of the rotor. Rotating pulse signal generating means for
In a wheel speed detection device comprising wheel speed calculation means for detecting a wheel rotation direction based on a direction signal included in the rotation pulse train signal and calculating a wheel speed according to a period of the rotation pulse train signal,
When the detected rotation direction of the wheel is a direction for moving the vehicle backward and the calculated wheel speed is larger than a predetermined value, an abnormality in the rotation pulse train signal generated from the rotation pulse signal generating means is detected. A wheel speed detecting device provided with an abnormality determining means for determining.   2. The wheel speed detection device according to claim 1, wherein the abnormality determination unit further determines abnormality of the rotation pulse train signal in addition to a condition that a determination condition relating to the rotation direction continues to be satisfied for a predetermined time or more. 3. The abnormality determination unit according to claim 1, wherein the abnormality determination unit further determines an abnormality of the rotation pulse train signal on condition that a minimum wheel speed of the plurality of wheel speeds is larger than a predetermined wheel speed. Wheel speed detection device.

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