JPH0611272Y2 - Anti-skid controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an anti-skid control device, and in particular, supplies left and right wheel speeds to a plurality of arithmetic devices, and uses the logical sum of control outputs of the plurality of arithmetic devices as an actuator. The present invention relates to an anti-skid control device that operates.

[Prior Art] An anti-skid control device that performs anti-skid control based on the outputs of wheel speed sensors provided on the left and right wheels is disclosed in, for example, Japanese Patent Publication No. 53-42178, "Brake Control System".
However, since this type of anti-skid control device has only one arithmetic unit, which is the center of the anti-skid control operation, a failure of the arithmetic unit means that the anti-skid control operation is immediately stopped. Was there. Further, even if the same single arithmetic unit is used, in order to eliminate malfunction due to a failure, for example, a device disclosed in Japanese Utility Model Laid-Open No. 57-147152 "Fault detection device for anti-skid control device" is controlled. It is known that a malfunction is prevented with a simple configuration by determining a failure when at least two wheel speed differences among a plurality of wheels are equal to or more than a threshold value.

However, the above-mentioned failure detection device determines the threshold value serving as a criterion for failure determination in consideration of the variation in the wheel speed based on the inner wheel difference during turning, and therefore the wheels allowed by the threshold value. The upper limit of the speed difference is the output of the wheel speed sensor f
When the wheel speed difference is caused by the f / v conversion error, there is a risk that the anti-skid control operation based on incorrect information is performed. . Further, even if the wheel speed sensor is operating normally or an abnormality occurs in the arithmetic unit, this type of abnormality cannot be detected, so that there is a drawback that erroneous control cannot be avoided.

On the other hand, a multi-system anti-skid control device in which a plurality of arithmetic devices are arranged in parallel has been introduced as a means for improving the drawbacks of a single system that relies on a single arithmetic device. The conventional anti-skid control device shown in FIG. 3 has a plurality of actuators 15 (two here) which are anti-skid control terminals in order to improve reliability of anti-skid control operation and reliability of fail-safe or warning. It is configured to be operated by the arithmetic unit 12 of. Specifically, the wheel speed signals output by the wheel speed sensors 11 provided on the left and right wheels are supplied to two arithmetic devices 12 having the same configuration, and these arithmetic devices 12 respectively operate on the left and right wheels. The speed signal is appropriately quantized by the number of bits and used as digital data for calculating the slip ratio. Since the slip ratio for optimum braking is set in advance in the arithmetic unit 12 as the target slip, each arithmetic unit 12 controls the actuator 15 so that the slip ratio obtained by the calculation matches the target slip ratio. Supply a signal.

As the actuator 15, for example, three series of control terminals such as a pair of solenoid valves for pressurizing or depressurizing hydraulic oil sent to a hydraulic brake, and a relay for turning on / off a pump motor for rotationally driving a hydraulic pump are illustrated. However, the two arithmetic devices 12 output predetermined control signals for each series. It is common for these control signals to match for each series when there is no abnormality in the arithmetic unit 12, but since there may be a mismatch due to a malfunction of one arithmetic unit 12, here, an AND gate for each series is used. The logical product of the control signals is taken at 13 and then supplied to the corresponding actuator 15 via the driver 14. Therefore, even if an error of several bits occurs in the control signal between the arithmetic units 12 and 12 due to the quantization error generated when the two arithmetic units 12 quantize the pair of wheel speed signals, the quantization error is generated. Substantially acts on the side that suppresses the control signal, and the safety of the system is maintained.

[Problems to be Solved by the Invention] In the above-described conventional anti-skid control device, even if one arithmetic unit 12 outputs an excessive control signal due to a malfunction,
As long as the other computing device 12 operates normally, the malfunction of the actuator 15 can be prevented. However, when a failure occurs in which one arithmetic unit 12 does not output a control signal, the normal output of the arithmetic unit 12 does not reach the actuator 15 even if there is no abnormality in the other arithmetic unit 12, and therefore the anti-skid There is a problem that the control operation practically falls into a stopped state, and there is no point in arranging the arithmetic units 12 in parallel.

Further, in order to enhance the function maintaining ability for a partial failure of such a multi-system arithmetic device, for example, JP-A-54-4720 is used.
In the system shown in No. 9 "Automatic train controller", 2
If the control outputs of the two arithmetic units are logically ORed to obtain a braking signal, and the control outputs of the two arithmetic units are exclusive ORed, it is determined whether or not the two control outputs match or do not match. Is a failure detection method that is regarded as a failure, and this failure detection method is further improved to introduce not only control output but also determination of whether the wheel speeds detected for each series are in agreement or inconsistency into the failure detection. If the wheel speeds do not match, including the possibility, synchronize the wheel speed signals in the speed detection unit so that braking is forcibly applied,
As a result, a failure detection method is disclosed in which the control outputs are eventually made to match and, even if the control outputs or the wheel speeds are not matched, a failure is determined. However, the failure detection method before improvement determines that there is a failure when the control output does not match even one bit, so that the failure is detected even when the wheel speeds do not match within the range of the measurement error. However, there is a problem in that the failure detection is too strict to be practically useful. Further, the improved failure detection method is also a safe side for ATC (automatic train control device) because the braking is forcibly applied by a method called synchronization when the wheel speed signals do not match, which is a failure. Special methods, such as intentional braking for detection, have to be enforced, so applying this kind of fault detection method to an anti-skid controller that mechanically complements vehicle braking is This means that braking is applied regardless of the intention of braking, and there is a problem that it is rather an adverse effect in that it gives the driver a feeling of strangeness.

Further, as in the multiplex system disclosed in Japanese Patent Application Laid-Open No. 51-110936, "Highly Reliable Duplex Controller", the control signals output from a pair of main and sub arithmetic units used for controlling the steam pressure of a nuclear reactor are monitored and controlled. There is also known a failure detection device that eliminates an irrational control signal in terms of the state quantity. However, since the failure criterion of the main processing unit or the sub-processing unit depends on the state quantity of the reactor, not only the judgment criteria dynamically change, but also the function that relates the state quantity and the allowable error is determined. There is a lot of room to select the coefficient or constant to be used.Therefore, depending on the selection of the coefficient or the constant, it is inevitable that the failure judgment will be affected significantly. There was a problem that it couldn't be sweet.

The present invention has been made in view of the above circumstances in order to eliminate the problem, and when a failure occurs in the arithmetic device, fail-safe or warning can be surely performed, and one arithmetic device can be provided. An object of the present invention is to provide an anti-skid control device capable of performing an anti-skid control operation by a normal operating device that remains even if a failure occurs.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a pair of wheel speed sensors provided on the left and right wheels for detecting wheel speeds respectively, and a pair of wheel speed sensors from the pair of wheel speed sensors. A plurality of arithmetic devices having the same configuration that take in speed signals as a pair, quantize the pair of wheel speed signals to calculate the slip ratio of the wheels, and output control signals so that the slip ratio matches the target slip ratio. An OR gate that takes the logical sum of the control signals output by the plurality of arithmetic devices, an actuator that changes the braking force for the wheel by the output of the OR gate, and the control signals output by the plurality of arithmetic devices are compared with each other. An operation limiting signal is supplied to the actuator when a difference exceeding a permissible value based on a quantization error associated with the quantization occurs between the plurality of control signals. It is characterized by comprising a monitoring means.

[Operation] According to the configuration of the present invention, the outputs of the left and right wheel speed sensors are respectively supplied to a plurality of arithmetic devices having the same structure, and each arithmetic device quantizes a pair of wheel speed signals to calculate the slip ratio of the wheel. However, by supplying a control signal output so that the slip ratio matches the target slip ratio to the actuator via the OR gate, the actuator can be reliably operated even if one of the arithmetic units fails. In addition, when there is a difference between control signals output from a plurality of arithmetic units that exceeds a permissible value based on the quantization error associated with the quantization, an operation limiting signal is supplied to the actuator, and thus fail safe. The warning is surely executed.

Embodiments Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is an overall circuit configuration diagram showing an embodiment of the anti-skid control device of the present invention.

The antiskid control device shown in FIG. 1 includes, as the actuator 5 serving as an antiskid control terminal, a pair of solenoid valves for pressurizing or depressurizing the hydraulic oil sent to the hydraulic brake, and a hydraulic pump, as in the conventional case. A total of 3 relays that turn on and off the pump motor that drives the motor
The control terminal of the sequence is illustrated. Also, two arithmetic devices 2 for controlling these three series of control terminals are provided in common for each series of actuators 5, as in the conventional case.

Further, the wheel speed signals output from the wheel speed sensors 1 provided on the left and right wheels are also supplied to the two arithmetic devices 2 in pairs, and each arithmetic device 2 appropriately outputs the left and right wheel speed signals to bits. It is quantized by a number and used as the digital data for the calculation of the slip ratio. Further, each computing device 2 supplies a control signal corresponding to each actuator 5 in accordance with the difference between the slip ratio obtained by the calculation and the target slip ratio, and performs control so that the slip ratio and the target slip ratio match.

By the way, the control signals output by the two arithmetic units 2 for each series are ORed not by the AND gate 13 but by the OR gates 3 provided for each series, and then the corresponding actuator 5 via the driver 4. It is configured to be supplied to. Further, in order to compare and monitor the control signal output from the arithmetic unit 2, a comparator 6 is provided for each series, and when a difference exceeding a permissible value based on the quantization error due to the quantization occurs between the control signals, the comparator 6 The operation limit signal output by the control unit 6 is supplied to the actuator 5 via the OR gate 7. That is, the comparator 6 and the OR gate 7 constitute a monitoring means for monitoring the operation of the arithmetic unit 2, and the output of the OR gate 7 is a fail-safe signal for stopping the operation of each actuator 5 or a warning signal for notifying an abnormality to the outside. Becomes

In such a configuration, assume that a failure occurs in which one of the arithmetic units 2 does not output a control signal. In this case, the control signal output from the normal arithmetic unit 2 is supplied to the actuator 5 via the OR gate 3, so that the anti-skid control operation is reliably performed.

In addition, when the arithmetic unit 12 quantizes a pair of wheel speed signals, an error of several bits may occur in the control signal between the arithmetic units 12 and 12 due to the quantization error. When the output error exceeds the value and at least one of the comparators 6 outputs the operation limiting signal. As a result, the OR gate 7 outputs a fail-safe signal, that is, a signal for stopping the erroneous operation of the actuator 5 and switching to the normal braking state, or outputs a warning signal to notify the abnormality to the outside. Therefore, even if one of the arithmetic units 2 is abnormal, safety is ensured.

On the other hand, when an error of about ± 1 bit occurs in the control signal between the arithmetic devices 12 and 12 by calculating the quantization error when quantizing the wheel speed signal or the data including the quantization error, The comparator 6 does not output the operation limit signal because the error is less than the allowable value based on the quantization error. Therefore, the system abnormality is notified by a temporary error factor, or the anti-skid operation is unnecessarily interrupted. There is no such thing.

In the above embodiment, the importance of anti-skid control operation in the three series of actuators 5 is treated equally. However, in reality, the importance of anti-skid control operation in these three series of actuators 5 is somewhat different. It is also true that there is a difference. Therefore, the output of the comparator 6 for abnormality determination is not supplied to the OR gate 7 with a weight of 1, but the output of the comparator 6 is weighted differently as in the anti-skid control device shown in FIG. When the output of the comparator is set to "1", the importance determination circuit 8 which multiplies the output by the corresponding weight and adds
May be provided, and a fail-safe signal or a warning signal may be output when the added value obtained in the importance determination circuit 8 exceeds a threshold value that defines the safety limit.

Further, in the above embodiment, the comparator 6 for detecting abnormality is provided on the output side of the arithmetic unit 2 to limit the operation of the actuator 5. However, for example, the arithmetic units 2 are connected by a bus line, and both arithmetic units are connected. 2 may compare the calculation results of each other and output the operation limiting signal of the actuator 5 from the calculation device 2. In short, an output difference exceeding the allowable value based on the quantization error occurs between the calculation devices 2 and 2. In this case, the operation limit signal may be output to the actuator 5.

Furthermore, in the above embodiment, the case where the actuators 5 controlled by the arithmetic unit 2 have three series has been taken as an example.
The number of control terminals may be two or four or more, and the number of arithmetic units 2 is not limited to two and may be three or more.

[Effects of the Invention] As described above, according to the present invention, when an abnormality occurs in the arithmetic device, a fail-safe signal or a warning signal can be output to prevent malfunction of the actuator, and one arithmetic device can be used. Does not output a control signal Even if a failure occurs, if the difference in the control output of the arithmetic unit is less than the allowable value based on the quantization error that occurs in the process of quantizing the wheel speed signals, the normal arithmetic unit does The control operation can be performed, and the focus is placed on the detection of the failure of the arithmetic device. This eliminates the inconvenience that the anti-skid operation is unnecessarily interrupted by a slight output error, and the actuator is stopped only when it is really necessary. There is an effect that it is possible to notify the abnormality or to notify the abnormality.

[Brief description of drawings]

FIG. 1 is an overall circuit configuration diagram showing an embodiment of the antiskid control device of the present invention, FIG. 2 is a partial circuit path configuration diagram of another embodiment of the antiskid control device of the present invention, and FIG. FIG. 7 is an overall circuit configuration diagram showing an example of a conventional anti-skid control device. 1 ... Wheel speed sensor 2 ... Arithmetic device 3 ... OR gate 5 ... Actuator 6 ... Comparator 7 ... OR gate 8 ... Importance judgment circuit

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Claims (1)

[Scope of utility model registration request] 1. A pair of wheel speed sensors, which are provided on the left and right wheels and detect wheel speeds respectively, and a pair of wheel speed signals from the pair of wheel speed sensors, respectively. To calculate the slip ratio of the wheels and output a control signal so that the slip ratio matches the target slip ratio, and a logical sum of the control signals output by the plurality of calculation devices having the same configuration. The OR gate to be taken, an actuator for varying the braking force with respect to the wheel by the output of the OR gate, and the control signals output from the plurality of arithmetic units are compared with each other, and the quantization error caused by the quantization between the plurality of control signals is compared. And a monitoring means for supplying an operation limiting signal to the actuator when a difference exceeding a permissible value based on Control device.