JPS5930589B2 - Wheel lock control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wheel lock control system for a vehicle having braked wheels.

No. 3,953,080, assigned to the present applicant, describes a system for providing wheel lock control that is particularly suitable for large trucks with air brakes and is adaptable to various vehicle loads and road conditions.

The present invention relates to a wheel lock control system with improved ability to adapt to vehicle and road conditions.

The present invention includes means for supplying a wheel speed signal indicative of wheel speed, and a means for providing a wheel speed signal that is responsive to the uncontrolled speed signal and that is activated when the rate of change in wheel speed exceeds a predetermined deceleration threshold indicating the start of wheel lock. a cycle depth integrator for generating a cycle depth signal; and a cycle depth integrator responsive to the control signal and the cycle depth signal for a period of the control signal and a period in which the cycle depth signal exceeds a reference value. control means for releasing the middle wheel brake, the cycle depth integrator having means for providing an acceleration signal indicative of the acceleration of the wheel in response to the speed signal, and a deceleration signal indicative of the maximum deceleration of the vehicle during brake application. means for supplying a reference signal, the deceleration reference signal being stopped during brake release, further comprising means for integrating the sum of the acceleration signal and the deceleration reference signal to provide a cycle depth signal. The cycle depth signal is a composite signal having a first portion indicating the amount by which the time integral of the deceleration reference signal exceeds the wheel speed during brake application, and a second portion representing the integral value of the amount of wheel acceleration during brake release; means for adjusting the cycle depth signal output of the integrating means to the cycle depth signal value that should be obtained when the deceleration reference signal is continuously added to the acceleration signal in response to the brake reactivation; After repetition, if the average wheel deceleration exceeds the maximum possible vehicle deceleration and the wheels are approaching a locked state, the cycle depth signal value exceeds the reference value and the brakes are released and the wheels are accelerated to approach the vehicle speed. A wheel lock control system for a vehicle with braked wheels is provided to prevent wheel locking phenomena.

The preferred embodiment of the wheel lock control system of the present invention allows for three modes of operation, each operating under specific vehicle loads and road conditions to collectively provide particularly effective wheel lock control. do.

In practice, the system functions as a deceleration switch under certain load and road conditions, as a wheel recovery system under other loads and road conditions, and as a wheel acceleration switching circuit under other conditions. It operates as.

The deceleration switch is activated to release the brake when the wheel deceleration exceeds the reference deceleration level in the three modes.

In the first mode of operation, the brake release period is controlled by a deceleration switch, which reactivates the brake when the deviation of the wheel speed from the integral of the reference deceleration during the release period becomes zero. .

This mode of operation is generally carried out in the case of high vehicle loads and/or high friction coefficients of the road surface.

In the second mode of operation, the brake release period is controlled by comparing the output of the cycle depth integrator to a cycle depth reference value having a value determined by wheel speed, wheel acceleration, and average wheel deceleration.

The output of the Saimine depth integrator is a first part indicating the amount by which the time integral of the production reduction reference signal exceeds the wheel speed during brake application, or in other words, the amount by which the wheel speed decreases below the reference speed at which the wheel speed is decelerated at the reference deceleration. , and a second portion that is the integral of wheel acceleration during brake release.

The second deceleration reference value is approximately equal to the reference deceleration level associated with the deceleration switch and generally represents the maximum possible deceleration level for the vehicle.

During normal wheel lock control operation, the average wheel deceleration is equal to or less than the reference deceleration, and therefore the cycle depth signal has a value indicative of the wheel speed change during the brake release period (hereinafter referred to as cycle depth).
.

The brake release period in the second mode of operation provides for recovery of wheel speed and is a function of the magnitude and duration of the cycle depth and the magnitude of the cycle depth reference value.

This mode of operation is generally carried out at moderate vehicle loads and/or at moderate road surface friction coefficients.

In the third mode of operation, the brake release period is controlled by a release convergence circuit which is responsive to wheel acceleration and is activated when the wheel acceleration decreases to a small value indicating that the wheel speed is approaching vehicle speed. Reactivate the brakes.

This mode of operation is generally carried out for light vehicle loads and/or low friction coefficients of the road surface.

A reset appositive is provided to reset the cycle depth signal output from the cycle depth integrator on each brake re-application, the circuit ensuring that the second deceleration reference value is continuous with the wheel acceleration signal throughout the brake release and application period. The cycle depth signal value is reset to the value that the cycle depth signal should reach if added to.

If the average wheel deceleration is less than the reference deceleration, the cycle depth signal is reset to zero.

However, if the average wheel deceleration exceeds the maximum possible vehicle deceleration, indicating that the wheels are approaching a locked condition, the cycle depth signal increases in value with each reset and cycles during the brake release period. When a value exceeding the depth reference value is reached, the wheel brakes are kept in a released state and the wheel speed is increased so that the wheel speed approaches the vehicle speed, thus preventing a wheel lock condition.

Preferred embodiments also include a fault monitoring and shutoff circuit.

The self-monitoring circuit of the wheel lock control system is generally configured to latch when a failure is detected;
Additionally, a warning and lock control cut-off circuit is provided.
Because both were latched, it was necessary to cycle the power to the wheel lock control system to reset the self-monitoring warning and shutoff device.

Since temporary and self-healing failures may occur in wheel lock control systems, it is preferable to provide a non-latching self-monitoring device, so that if a detected failure resolves automatically, The lock control system is restarted.

Accordingly, in a preferred embodiment, a fault monitoring and shutoff circuit is provided which inhibits release of the vehicle brakes in response to detection of a fault condition.1. The inhibition can be latched or non-latched depending on whether the wheel lock control system is commanding brake release.

This fault monitoring and shutoff device is the wheel lock control 7
Logic circuitry is provided for monitoring selected parameters of the stem and providing a fault signal while the parameters indicate a fault, and responsive to the fault signal and a brake release signal generated by the wheel lock control system to provide an inhibit signal. The prohibition signal is initiated only by the fault signal and is stopped only when both the fault signal and the brake release signal stop, and therefore the prohibition signal is a temporary fault that occurs during a period other than the brake release signal period. and if the fault signal coexists at least momentarily with the brake release signal, then during the longer period of the fault signal or the brake release signal.

The present invention will now be described with reference to the accompanying drawings.

Although the following description of the preferred embodiments relates to the application of the invention to heavy duty trucks with air brakes, the invention may be applied generally to all types of vehicles and braking systems.

In a preferred embodiment of the invention, each axle on the tug and tow vehicle is controlled independently of the other axles, each axle is equipped with a complete wheel lock control system, and each axle's brake system is It is assumed that only the air pressure, which is manually controlled by the driver's will, is common.

However, it is also possible to brake all 31 existing axles with a single locking control system.
It is also possible to create arbitrary combinations of wheels, axles and control stems.

The system of the present invention detects the onset of a wheel lock phenomenon when brake pressure is applied to the vehicle brakes by the driver, releases the brakes for a period determined by the system, then re-applies the brakes, and performs this cycle as desired. It is based on the known principle of repeating as many times as necessary to obtain a braking effect.

In this text, the term "acceleration" refers to both acceleration and deceleration, unless otherwise specified, unless otherwise specified.

In addition, "cycle depth" indicates the amount of change in wheel speed during the brake release period from the wheel speed at the time of wheel brake release.

In FIG. 1, wheels 10 and 12 at both ends of the axle are respectively provided with speed detectors 14 and 16 for detecting wheel speeds.

The detectors are preferably toothed variable reluctance electrode transducers, each providing an alternating current signal having a frequency proportional to the wheel speed.

The signals are each sent to a rectangular amplifier 18, 20, resulting in a square wave signal of the same frequency as the alternating current signal from the detectors 14,16.

The square wave signals from the intensifiers 18.20 are each applied to a tacho generator circuit 22.24, resulting in an analog electrical signal each having a magnitude proportional to the wheel speed.

The analog signal is provided to a speed selector 26 which transmits a signal on line 28 indicative of low wheel speed.

Wheel speed signals on line 28 are connected to deceleration switch 30, cycle depth integrator 32, deceleration multiplier 34, and acceleration switch 3.
6, release prohibition switch 38, and cycle depth comparator 4
0 negative input.

Cycle depth comparator 40 generates a brake release signal when the signal value on its positive input is greater than the signal value on its negative input.

The brake release signal is sent to the lensoid drive and cutoff circuit 42.
The circuit energizes the release solenoid 44 to release the brake during the brake release signal.

The deceleration switch 30 generates a control signal when the wheel deceleration exceeds a reference deceleration indicating the start of a wheel lock condition.

The reference deceleration is approximately the same as the maximum possible vehicle deceleration and is variable as a function of wheel speed.

In this embodiment, the reference deceleration indicating the onset of wheel lock is assumed to be 0.9 g at zero wheel speed and 1.3 g at wheel speed 60 mph.

The deceleration switch 30 stops the control signal when the change in wheel speed from the integral of the reference deceleration being released approaches zero.

A control signal is provided to the positive input of cycle depth comparator 40.

The cycle depth integrator 32 provides a cycle depth signal to the cycle depth comparator 42, which signal has a first portion indicating the amount by which the integral of the reference deceleration exceeds the wheel speed during brake application and a first portion indicating the amount by which the integral of the reference deceleration exceeds the wheel speed during brake application. It is a composite signal consisting of a second part which is an integral value of heavy wheel acceleration at .

The deceleration reference value for the cycle depth integrator 32 is approximately equal to the deceleration reference value for the deceleration switch 30, and therefore the cycle depth signal from the cycle depth integrator 32 is generally equal to the magnitude of the wheel speed change (cycle depth) during the brake release period. Show that.

In this embodiment, the deceleration reference value is assumed to be O, 1g.

The cycle depth comparator 40 brake release signal acts to stop the deceleration reference value in the cycle depth integrator 32 during that period.

When the release signal from the comparator 40 is stopped for brake re-application - the cycle depth signal is equal to the amount by which the time integral of the reference deceleration exceeds the wheel speed during the rain period of brake application and release. Set.

If the average wheel deceleration is less than the reference deceleration, the cycle depth signal is set to zero.

If the average wheel deceleration is greater than the reference deceleration, the cycle depth signal is set to the aforementioned value.

A deceleration amplifier 34 provides a cycle depth reference signal whose magnitude is proportional to deceleration until it saturates at a predetermined deceleration level minus the deceleration reference value at deceleration switch 30.

For example, in this embodiment, the deceleration multiplier 34 becomes saturated when the wheel deceleration reaches approximately 0.8 g.

The deceleration amplifier 34 is configured so that the deceleration switch 30 always goes low before its output goes low.

Therefore, the cycle depth reference signal output of the deceleration amplifier 34 exists beyond the time when the control signal from the deceleration switch 30 is stopped.

The cycle depth reference output of the deceleration amplifier 34 is supplied to the output of the gate 46.

When the acceleration switch 36 detects a predetermined high level of wheel positive acceleration, it outputs a cycle depth reference signal.

For example, in this embodiment, the cycle depth reference signal is output when the positive acceleration of the wheels reaches approximately 2.0 g.

The output of the acceleration switch 36 is provided to the second input of the gate 46, the output of which is applied to the negative input of the cycle depth comparator 40.

Gate 46 serves to provide either the cycle depth reference signal from deceleration amplifier 34 or acceleration switch 36 to the negative input of cycle depth comparator 40.

The sum of this signal and the wheel speed signal provided to cycle depth comparator 40 negative human power indicates the cycle depth reference value to which the cycle depth represented by the cycle depth signal from cycle depth integrator 32 is compared.

In this embodiment, the saturated output of the deceleration amplifier 34 indicates a cycle depth of 3 miles per hour, and the output of the acceleration switch 36 when a positive acceleration level is detected indicates a cycle depth of 3 miles per hour.

Additionally, the wheel speed power from line 28 to the comparator 40 negative power provides a cycle depth reference component equal to approximately 1.5 miles per hour for every 10 miles per hour of wheel speed.

The release inhibit switch 38 is an "always on" type switch that provides a release inhibit signal to the negative input of the comparator 40.

The signal is generated by the control signal generated by the deceleration switch 300.
Alternatively, it is stopped upon detection of positive acceleration exceeding a predetermined low acceleration level that is variable as a function of the cycle depth signal value.

For example, in this embodiment, the release prohibition switch 38 outputs a release prohibition signal when a positive acceleration of 0.59 is detected when the cycle depth signal value is zero, and when a positive acceleration of 0.1 g is detected for the maximum cycle depth signal value. stop.

In the absence of the control signal and when the wheel forward acceleration begins to decrease below a predetermined low level, the switch release prohibition signal is generated again.

The release inhibit signal value from the switch 38 is greater than the maximum value of the cycle depth signal from the cycle depth integrator 32.

Therefore, the brake release signal is initiated by the output of the cycle depth comparator 40 only by the control signal generated by the deceleration switch 30 when the wheel deceleration exceeds the deceleration reference value of the deceleration switch 30, which indicates the start of a wheel lock condition.

Additionally, the control signal value from the switch is greater than the cycle depth reference signal bottom input to the comparator 40, so that the control signal always generates a brake release signal and releases the brakes during that period.

After the control signal initiates release, the response of the system varies as a function of the length and depth of the wheel cycle as represented by the cycle depth signal of the cycle depth integrator 32, vehicle deceleration, and wheel acceleration.

For high vehicle loads and/or high coefficients of friction, the cycle depth is typically short and shallow; the wheel lock control is activated only by deceleration switch 300 action.

In this operating mode, the brake is reactivated by stopping the control signal from the deceleration switch 30.

This mode of operation exhibits optimal functionality at high loads and/or at high coefficients of friction on the road surface.

When the surface friction coefficient and/or vehicle load is moderate, the wheel speed cycle depth is long and the cycle depth signal from the integrator 32 is fed to the negative input of the cycle depth comparator 40 along with the cycle depth reference signal to determine the brake. Controls the duration of the release signal.

In this mode of operation, the cycle depth signal value is greater than the cycle depth reference signal value provided to the negative input of the cycle depth comparator 40 when the control signal from the deceleration switch 30 is stopped, and the brake release signal is less It is extended until the depth decreases below the reference cycle depth.

This mode of operation performs best for moderate road surface friction coefficients and/or vehicle loads.

In the case of light vehicle loads and/or low road friction coefficients, the disable switch 38 enters a third mode of operation, and the cycle depth signal from the integrator 32 indicates that the wheel pressure acceleration is reduced to a low level and the wheel is on the vehicle. The inhibit switch 38 maintains the released state until the brake is forcibly reactivated when the vehicle speed approaches the vehicle speed and indicates that the vehicle is approaching the speed.

When the wheel positive acceleration is at a low level, the switch 38 generates a release prohibition signal, stops the brake release signal, and reactivates the brake.

This mode of operation exhibits optimal functionality under light vehicle loads and/or when the road surface has a low coefficient of friction.

The remainder of the circuit of FIG. 1 provides a self-monitoring function that monitors the wheel lock control system for failures, shuts the system down, and alerts you to the occurrence of a failure.

The self-monitoring circuit includes a detector monitoring circuit 48 which is responsive to the speed detectors 14,16 and provides a fault signal to the timer 50 if a circuit break is detected in any of them.

Another fault signal is sent from power supply 52 to timer 50 when vehicle battery voltage B+ drops to a level below wheel lock control system regulation voltage Z.

The release solenoid 42 also sends a signal to the timer 50 when the release solenoid 44 is disconnected or shorted to ground and during the period when the solenoid 44 is energized to release the wheel brakes.

The timer is activated if a fault signal from detector monitoring circuit 48 or power supply 52 exceeds a predetermined period, or if the release solenoid is disconnected or shorted to ground, or if the integrator 32 exceeds a period determined as a function of the cycle depth signal. When excited to release the brake, the comparison circuit 54 generates an output at the trigger level.

Comparator 54 responds to the trigger level timer 50 output and sends a cutoff signal to solenoid drive cutoff circuit 42 to deenergize solenoid 44 and stop brake release, or prevent energization of the solenoid and thus initiate brake release. To prevent.

To prepare for self-healing failures and to prevent the lock control circuit from releasing the brakes during the brake release signal if the failure is detected during the brake release signal, the comparator 54 instructs the wheel lock control system to release the brakes. It is latched or non-latched depending on whether it is latched or not.

Comparator 54 receives a signal indicative of the output of the solenoid drive disconnect circuit 42 or lock control system.

If a fault occurs while the system is braking and is subsequently cured, the shutoff signal from comparator 54 will only occur during the fault period.

However, if a fault coexists even momentarily with the brake release signal from cycle depth comparator 40, comparator 54 generates a shutdown signal for the duration of the fault condition or the brake release signal, whichever is longer.

Thus, the brake release signal latches comparator 54 and generates a shutdown signal during that period.

When the shutoff signal stops, the wheel lock control is reactivated.

A fault signal from the comparator is provided to the lamp drive circuit and lamp indicator 56 to provide an indication of a fault condition.

A dynamic monitoring circuit 58 is also provided to monitor the detector 14.16 for failures other than disconnection.
The wheel speeds from 4 are monitored and the output is sent to a cycle depth comparator 50 to release the brakes if one wheel speed exceeds the other by more than a certain amount (17 mph in this example).

The output of the dynamic monitoring circuit 58 is maintained beyond the maximum weir time and continues to release until the self-monitoring circuit generates a shutdown signal and shuts off the wheel lock control circuit.

Next, FIG. 2a12b showing an embodiment of the system of FIG. 1 will be described.

Power supply 52 provides a regulated voltage 2+ for operation of the wheel lock control system.

Unregulated voltage B+ from the vehicle battery is provided through a circuit consisting of resistor 60, Zener diode 62, and resistor 64.

The Zener diode provides a regulated voltage, which is supplied to the base of an NPN transistor 660 whose collector potential is connected to battery B+.

Transistor 66 is biased to provide a regulated voltage Z+ equal to the Zener diode 620 cathode voltage minus the base-emitter voltage drop of transistor 66.

Voltage 2+ is developed across resistor 68.

The remainder of the power supply 52 is such that the battery voltage B+ is equal to the required voltage Z.
This relates to the generation of a fault signal when the value drops below + and affects the operation of the lock control equivalent.

This fault signal has an emitter grounded and a collector resistor 72.
NP connected to the emitter of transistor 66 via
N) Performed by Landistav 0.

When the battery voltage B+ exceeds the conduction voltage of the Zener diode 62, the voltage drop across the resistor 64 causes the transistor 70 to become conductive and thus the collector potential becomes zero or a value close to it.

Also); when the battery voltage B+ becomes lower than the conduction voltage of the Zener diode 62, the transistor 70 is biased to be non-conductive, the collector potential becomes almost the same as the battery voltage B+, and a signal indicating a failure is sent through the diode 73.

This fault signal is sent to timer 50 via line 74.

A shortened amplifier 18 connects the detector 14 between voltage Z+ and ground.
It has a resistor 76 connected in series to the output coil of.

The AC output of the detector 14, which indicates the speed of the wheel 10 at one end of the axle, is applied to the positive input of the operational amplifier 78 through a series resistor 80,82.

Voltage Z+ is provided via capacitor 84 to the junction between resistors 80 and 82 and via resistor 86 to the positive input of amplifier 78.

The negative input of amplifier 78 is biased by a voltage divider consisting of resistor 88,90 connected in series between voltage Z+ and ground.

Further, a feedback resistor 92 is connected between the output of the amplifier 78 and the main power supply.

Amplifier T8 and the other operational amplifiers in Figure 2.12b are current amplifiers, where the current input to the positive terminal is subtracted from the input to the negative terminal, and the current input to the positive terminal subtracts the current input to the negative terminal. If the value exceeds the value, a positive output will be obtained.

Also, operational amplifiers usually provide high output when there is no current input to their input terminals.

A bias current provided to the negative input of amplifier 78 from a voltage divider having resistors 88 and 90 acts to bias the output of amplifier 78 to ground potential.

The rectangular amplifier 18 responds to the AC output from the velocity color detector 14 and provides a square wave output of the same frequency.

The rectangular amplifier 20 has a resistance of 94.96.98°100.1
02, 104, 106, has a capacitor 108 and an operational amplifier 110, is connected in the same way as the rectangular amplifier 18, and outputs a rectangular wave having the same frequency as the AC signal from the detector 16 and corresponding to the speed of the wheel 12. do.

The square wave output of amplifier 18 is provided to a differentiator circuit having resistor 112 and capacitor 114 in tacho generator 22.

A positive current pulse is applied to the positive input of the operational amplifier 116 through the diode 118 every time this square wave signal rises, and a negative current pulse is applied to the negative input of the operational amplifier 116 through the diode 120 every time the square wave signal falls.

The negative input terminal of the operational amplifier 116 is connected to ground via a capacitor 122.

A feedback capacitor 124 is provided between the output terminal and the negative input terminal of the operational amplifier 116 to form an integrator having an integrator defined by a feedback resistor 126 connected in parallel thereto.

The output of the amplifier 116 is an analog voltage that is directly proportional to the speed of the wheel 10.

The tacho generator 24 has resistors 128, 130 . It has capacitors 132, 134, 136, diodes 138, 140, and an operational amplifier 142 connected similarly to the tacho generator circuit 22, the output of which is an analog voltage directly proportional to the speed of the wheel 12.

A speed selector 26 is responsive to the wheel speed signal from the tacho generator 22.24 and provides a wheel speed signal on line 28 equal to the speed of the slower of the wheels 10.12.

The selector 26 has a collector grounded and an emitter connected to the resistor 14.
8 to the regulated voltage 2+.

Wheel speed signals from tachogenerators 22, 24 are provided to the bases of transistors 144, 146, respectively.

The output from speed selector 26 on line 28 is the wheel speed signal which is the output value of tachogenerator 22 or 24 corresponding to the slower wheel plus the base-to-emitter voltage drop of conducting transistor 144 or 1460.

The deceleration switch 30 is connected to the line 28 carrying the wheel speed signal.
and the sum junction 154.
52 and a filter resistor 150 connected in series.

The input to the junction from capacitor 152 is a current having a value indicative of wheel acceleration.

This acceleration signal is summed at junction 154 with a current at a value representing a reference deceleration representing the maximum possible vehicle deceleration.

This reference deceleration signal consists of three parts, the first part being a voltage of 2
+ is supplied to junction 154 via resistor 156, and the second portion is a current proportional to wheel speed that is supplied from wheel speed signal carrying line 28 to junction 154 via resistor 158.

The reference deceleration signal supplied to junction 154 indicates a deceleration of 9 g at zero wheel speed and a wheel speed of 60 g/h.
Miles increase to 1.39.

The output from the junction, which is the sum of the wheel acceleration and reference deceleration signals, is provided through a resistor 162 and a diode 164 to the negative input of an operational amplifier 160.

A diode 166 is provided between the anode of the diode 164 and the output terminal of the operational amplifier 160.
Remove the velocity threshold introduced by 4.

The positive input terminal of the amplifier 160 is grounded.

Also, the feedback filter capacitor 168 is connected to the operational amplifier 160.
and the junction 1540.

When there is no wheel deceleration and the deceleration is smaller than the reference deceleration, the junction 1
The operational amplifier output is biased to ground potential by the reference deceleration current provided to 54 and supplied to the negative input of operational amplifier 160.

During wheel deceleration, the current from capacitor 152 is a function of the wheel deceleration and removes the current from junction 154.

When the wheel deceleration is such that the current of the capacitor 152 is equal to the reference deceleration current (when the wheel deceleration becomes equal to the reference deceleration and indicates a wheel lock start state), the operational amplifier 160
The output of the deceleration switch 300 changes to a positive voltage level including the control signal output.

Before the negative terminal input of the operational amplifier changes to zero, transistor 162 operates to set the required wheel speed change and generate the control signal.

This signal is applied to the release inhibition circuit via the diode 170 to stop the release inhibition signal, and the diode 17
2 to cycle depth comparator 40 for wheel brake release.

Due to delays in the brake system, the brake pressure continues to increase even after the deceleration switch 30 issues a control signal, so that the wheel deceleration is below the reference deceleration threshold.

The decreasing speed signal on line 28 is connected to junction 15
4, and the deceleration reference current supplied thereto serves to restore the voltage at junction 154 to approximately the threshold deceleration rate.

The voltage drop at junction 154 represents the amount of deviation in wheel speed on line 28 from the reference speed that decreases at approximately a threshold deceleration rate.

When the wheels stop decelerating and start accelerating, the amount of change in wheel speed from the time integral of the reference deceleration approaches zero (as the voltage at the junction 154 rises, at this point a current flows into the negative input of the operational amplifier 160). Stops the supplied control signal.

The control signal is applied through resistor 176 to the positive input of operational amplifier 174 in cycle depth comparator 40.

Cycle depth integrator 32 has a filter resistor 178 connected in series with a differential capacitor 180 between wheel speed signal line 28 and summing junction 182.

The input from capacitor 180 to junction 182 is a current indicative of wheel acceleration.

This acceleration signal is applied to the junction 182 at a reference deceleration of 1. It is selectively added to the current indicating Og.

This value is approximately equal to the deceleration switch 300 reference deceleration and represents the maximum possible vehicle deceleration.

The reference deceleration current is a resistor 18 connected in series with a PNP transistor 184, a junction 182, and a voltage Z.
6.188.

Capacitor 190 is provided in parallel with resistor 188.

A reference deceleration current is provided to junction 182 through transistor 184 when it is biased conductive.

The sum of the vehicle acceleration signal and the deceleration reference signal is connected to the diode 194.
The signal is applied to the negative input of the operational amplifier 192 via.

The positive input of the amplifier 192 is grounded. diode 19
A diode 196 is provided between the anode of 4 and the output of operational amplifier 192 to eliminate the speed threshold introduced by diode 194.

The operational amplifier 192 connects its output terminal to the junction 182.
A feedback capacitor 198 is provided between 0 and 0 to form an integrator.

The output of operational amplifier 192 is normally held at ground level by the deceleration reference current supplied to junction 182.

However, if the current flowing through capacitor 180 as a result of wheel deceleration exceeds the current supplied to transistor 184 or junction 182, the amplifier output becomes a cycle depth signal, which is the integral of the sum of currents, and the integral is zero or Progress is made to reach ground potential.

Conduction of transistor 184 is controlled by a brake release signal from cycle depth comparator 40 connected to the base of transistor 1840 through resistor 200.

Cycle depth comparator 40 in the absence of brake release signal
The output of is at ground potential and transistor 184 is biased conductive to transfer the decelerating reference current to junction 182.
give to

When the brake release signal occurs, transistor 184 is shut off and the cycle depth integrator integrates only the wheel acceleration signal sent to junction 182 via capacitor 180.

Therefore, the cycle depth signal is a composite signal consisting of a first part indicating the amount by which the time integral of the deceleration reference signal exceeds the wheel speed while the brake is applied, and a second part which is the integral of the wheel acceleration while the brake is released. The limit is zero.

Since the deceleration reference signal supplied to junction 182 via transistor 184 is approximately equal to the deceleration reference value supplied to junction 154 in deceleration switch 30,
The cycle depth signal output of the cycle depth integrator, which is generally indicative of the amount of change in wheel speed, occurs during the brake release signal from the cycle depth comparator 40, and therefore the cycle depth signal value from the cycle depth integrator is during the brake release signal supply period. This is an effective measure of the amount of change in wheel speed (i.e., the integral value of wheel acceleration).

A cycle depth signal indicative of the cycle depth is provided via resistor 202 to the input power of amplifier 174 within cycle depth comparator 40 .

During brake release, transistor 184 is off and capacitor 190 discharges through resistor 188.

The discharge rate is related to the deceleration reference current supplied to junction 182 while transistor 184 is on, so that when the brake release signal ends and transistor 184 conducts, the current pulse caused by recharging capacitor 190 flows through resistor 186. , whose amplitude and pulse width convert the cycle depth signal value from the cycle depth integrator to the cycle depth signal value that would be obtained if a reference deceleration value were continuously supplied to junction 182 through transistor 184. Set.

If the average wheel deceleration is less than the reference deceleration provided through resistors 186, 188, the cycle depth signal from the cycle depth integrator is reset to ground potential.

However, if the average wheel deceleration is greater than the reference deceleration provided through resistors 186, 188, then the cycle depth signal is set to that value.

As the wheel is further decelerated beyond the reference deceleration, the reset level of the cycle depth signal increases continuously.

As a result, the current supplied to the amplifier 174 via the resistor 202 increases.

The deceleration amplifier 34 is an operational amplifier 204 whose positive input is grounded.
has.

Filter resistor 206 and differential capacitor 208 are connected in series between wheel speed signal line 28 and junction 2100.

The current in capacitor 208 is indicative of wheel acceleration.

This signal is applied to the negative input of amplifier 204 via diode 212.

Feedback filter capacitor 214 is connected between the output terminal of amplifier 204 and junction 2100, and resistor 21
6 is connected in parallel to this.

The deceleration amplifier 34 provides a first portion of the cycle depth reference value, which value is determined by a predetermined deceleration level (0-8 in this example).
g) is proportional to the vehicle's deceleration until it reaches saturation.

After this, when the wheels decelerate further, junction 210
voltage decreases from the other resistor 216 to junction 2
The current flowing into 10 serves to restore the voltage to a level of approximately o,sg.

The voltage at junction 210 is then indicative of the deviation of the wheel speed from the reference speed, decelerating at the rate of deceleration indicated by the feedback from resistor 216.

As the wheels begin to accelerate and the wheel speed deviation approaches zero and the voltage at junction 210 increases, the output of the deceleration amplifier drops to ground potential.

The first portion of the cycle depth reference signal of the deceleration amplifier 34 indicates, for example, a cycle depth of 3 miles per hour when saturated.

The deceleration amplifier 34 is configured such that the acquisition signal generated by the deceleration switch 30 stops before the deceleration amplifier 34 saturates, so that each time the deceleration switch 30 stops the control signal, the gain signal generated by the deceleration amplifier 34 is The first portion of the cycle depth reference output will be at the highest level of 3 mph.

The acceleration switch 36 has a filter resistor 218 connected in series with a differential capacitor 220 between a summing junction 221 and a filter 2240 providing a signal indicative of wheel speed.

Filter 224 includes a resistor 226 and a capacitor 228 connected in series between wheel speed signal line 28 and ground.

The voltage across capacitor 228 is the f-wave wheel speed signal.

The current input from capacitor 220 to junction 221 is indicative of wheel acceleration.

A resistor 222 is connected between this junction 221 and ground.

Also, the junction 221 is connected to the PNP via the resistor 232.
) is connected to the base of the run raster switch 2300, its emitter is connected to the power supply Z, and its collector is connected to the negative power of the operational amplifier 234 via a resistor 236.

Current is supplied to the main power of amplifier 234 from power supply 2+ via resistor 238 .

The transistor switch 2300 base is connected to the resistor 222.
232 and is therefore always on.

The current output from the junction 221 via the resistor 222 has a value indicating the reference wheel pressure acceleration, which in this example is 2.
It is Og.

This acceleration reference signal is summed at junction 221 with the wheel acceleration signal from differential capacitor 220.

In the absence of wheel acceleration and less than the reference acceleration indicated by the current across resistor 222, the current from junction 221 through resistor 222 biases transistor 230 to the on state.

During wheel acceleration, capacitor 220 connects to junction 22.
1, the value of which is a function of the wheel acceleration.

If the current in capacitor 220 as a result of wheel acceleration is equal to the reference acceleration current (if the wheel acceleration is equal to the reference acceleration), transistor switch 230 is biased to the off state.

Resistor 232 sets the required wheel speed change value before transistor switch 230 is biased to the off state.

Amplifier 234 acts as a current/voltage amplifier and performs phase reversal so that its output is at a high level for positive accelerations exceeding the reference acceleration of 2.0 g.

This high level output of acceleration switch 36 includes a second portion of the cycle depth reference signal, which portion has a cycle depth of 3/hr.
Can show miles.

The first and second portions of the cycle depth reference outputs of deceleration amplifier 34 and acceleration switch 36 are connected to diode 2 of gate 46.
40,242 anode, whose cathode resistance 2
Amplifier 174 in cycle depth comparator 40 via 44
connected to the negative input of

Diodes 240, 242 serve to provide either the first or second portion of the cycle depth reference signal from deceleration amplifier 34 and acceleration switch 36 to amplifier 174.

The wheel speed signal on line 28 is applied through resistor 246 to the negative power of cycle depth comparator amplifier 174.

The current input from resistor 246 to amplifier 174 becomes the third component of the cycle depth reference signal and may indicate a cycle depth of 1.5 miles per hour for every 10 miles per hour of wheel speed.

The cycle depth reference value, including the second or third portion, is compared to the cycle depth indicated by the cycle depth signal output of the cycle depth integrator 32 to determine a particular operating mode of the wheel lock control system, as described below. to control the duration of the brake release cycle.

The release inhibition circuit 38 includes a filter resistor 245 and a differential capacitor 247 connected in series between a filter 224 that supplies a signal indicating the wheel speed and the negative input of an operational amplifier 248.

The capacitor 247 supplies the acceleration signal to the negative input of the amplifier 248. A feedback filter capacitor 250 is provided between the output and the negative input of the amplifier 248.

The first part of the positive acceleration reference signal to the release inhibition circuit 38 is a direct current supplied from the regulated voltage Z+ through the resistor 252 to the positive input of the amplifier 248, and the second part is a current with a value proportional to the cycle depth. The cycle depth signal is applied to the negative input of amplifier 248 through a resistor 254 connected to the output of a cycle depth integrator.

The actual positive acceleration reference value given by the input of the amplifier 248 indicates the wheel speed approaching the vehicle speed, and for example, indicates the wheel acceleration o,sg when the cycle depth is zero, and decreases to O,1g when the cycle depth is maximum. .

If the wheel is decelerating or making a positive acceleration less than the reference acceleration, the amplifier 248 is connected to the amplifier 17 of the cycle depth comparator 40 via the diode 256 and the resistor 258.
Send a release prohibition signal to the negative input of 4.

The cancellation prohibition signal is stopped when the wheel positive acceleration exceeds the reference pressure acceleration.

The signal is also generated by the deceleration switch 30 and is generated by the resistor 26.
It is also stopped by a control signal applied to the negative input of amplifier 248 via 0.

The release prohibition signal is supplied again when the control signal is stopped and the wheel forward acceleration is at a low level, indicating that the wheel speed is approaching the vehicle speed.

Cycle depth comparator 40, in addition to the above components, is connected between power supply 2+ and the positive terminal of amplifier 174 to eliminate wheel speed bias introduced by the emitter-base voltage drop of transistors 144, 146(7) of speed selector 26. It has a resistor 262 connected thereto.

A feedback resistor 264 is provided between the positive input and the output of amplifier 174 to provide a feedback current during the brake release signal, which is equal to or less than the cycle depth reference value proportional to wheel speed, for example, for a wheel speed of 25 miles per hour. Equal to three parts.

Resistors 176, 202, 244, 246, and 258 determine the cycle depth at which the current supplied to the negative input of amplifier 174 via resistor 258 during the period of the release inhibit signal from release inhibit circuit 38 is supplied by cycle depth integrator 32. It is set to be less than the current supplied to the positive input through resistor 202 during the maximum value of the signal.

Also, the current flowing to the positive input through resistor 176 during the control signal from the deceleration switch is greater than the maximum sum of cycle depth reference currents flowing through resistors 244 and 246 to the negative input.

Therefore, the cycle depth integrator 32 releases the brake, and the deceleration switch 30 itself generates a brake release signal and releases the brake upon detection of a wheel lock initiation condition, and maintains the brake in the released state for the duration of the control signal. .

Further, the release prohibition signal from the release prohibition circuit 38 always commands brake operation.

The output drive and compensation circuit 34 includes a Darlington transistor 266 which is controlled by the brake release signal and a Darlington transistor 268 which is controlled to shut off the lock control system and avoid brake release upon detection of a system failure.

Transistors 266 and 268 are resistors 270 and 272°2
74 to the vehicle batch 'J B+.

The emitter of transistor 266 is NPN) run raster 2
60 base, its emitter is grounded, and its collector is connected to one end of the release solenoid 44.

The connection point between resistors 270 and 272 is NPN) transistor 2
78, its emitter is connected to the battery voltage B+, and its collector is connected to the other end of the solenoid 44.

A resistor 2 is connected between the emitter and collector of the transistor 278.
80 are provided.

Shutoff transistor 268 receives a positive voltage from the supervisory circuit via line 282 and resistor 284 in the absence of a fault, and is therefore biased to the on state during normal operation of the lock control system.

The brake release signal from cycle depth comparator 40 is applied through resistor 286 to transistor 266 to bias it on, which turns on transistor 276 and applies ground potential to one end of solenoid 44.

At the same time, the current from resistor 270.272 flows through transistor 2
78 is biased on to apply battery voltage to the other end of solenoid 44.

As a result, the solenoid is energized and the cycle depth comparator 40
The vehicle brake is released during the period of the release signal from.

Upon termination of the brake release signal, transistor 266 is turned off to demagnetize solenoid 44, thereby reactivating the brake.

The operation of the wheel lock control logic circuit shown in Figures 2a and 25 will now be described with reference to Figures 3a-3d, which illustrate its three modes of operation.

In the previous figures 3a to 3d, curve A indicates the wheel speed value after the brake is released and is determined by the cycle depth indicated by the cycle depth signal from the cycle depth integrator 32, and curve B indicates deceleration at the reference deceleration of the deceleration switch 300. The curve C is the reference wheel speed that decelerates at the reference deceleration of the deceleration intensifier 34, and the curve C is the reference wheel speed that decelerates at the reference deceleration of the deceleration intensifier 34, the acceleration switch 36, and the wheel speed component line 28. is the cycle depth reference value supplied to the device 40.

The wheel lock control system becomes operable and controls the braking action of the vehicle when the brakes are applied and the wheel deceleration falls below the deceleration reference value of the deceleration switch 300.

The wheel lock control circuit has three operating modes in order to optimally control the brakes depending on the vehicle load and road surface conditions during operation.

In the three operating modes, the deceleration switch 30 can release the brake when the wheel deceleration exceeds the reference deceleration, indicating the beginning of wheel lock.

In the first mode of operation, the brake release period is controlled only by the deceleration switch 30.

This mode usually occurs when the load is high and/or the road surface has a high coefficient of friction, and the cycle depth during brake release tends to be shallow and short.

This mode of operation is shown in FIG. 3, in which when the wheel deceleration exceeds the reference deceleration at time t, the deceleration switch 30 sends a control signal to the release inhibition circuit to stop the release inhibition signal and cycle it again. The depth comparator 40 generates a brake release signal to energize the solenoid 44 and release the brake.

Even after the delay solenoid 44 in the brake system is energized, the brake pressure continues to increase, so that the wheel deceleration increases beyond the reference deceleration of the deceleration switch 30.

This can be seen in the cycle depth signal (curve A).

At time t1, the cycle depth value is the cycle depth reference value (
It becomes a dog from curve D).

At time t2, in response to the decrease in brake pressure (caused by brake release), wheel deceleration ceases and the wheels are accelerated toward vehicle speed.

At time t3, the cycle depth becomes less than or equal to the cycle depth reference value (curve D).

However, since the control signal is still being generated by the deceleration switch 30, the cycle depth comparator 40 still outputs the brake release signal.

At time t4, the deviation of the wheel speed from the reference speed (curve B) at which the wheel is decelerated at the reference deceleration of the deceleration switch 300 becomes zero, and the deceleration switch 30 stops the control signal.

At this time, the cycle depth reference signal supplied to the cycle depth comparator 40 exceeds the cycle depth, and due to the stop of the control signal from the deceleration switch 30, the output of the brake release signal from the cycle depth comparator is stopped, and the brake is moved forward. be moved.

If the average wheel deceleration becomes smaller than the deceleration reference value of the cycle depth integrator 32 due to the stoppage of the brake release signal, the cycle depth signal is reset to ground potential.

After this, the wheels stop accelerating and begin decelerating due to increased brake pressure.

This cycle repeats until the vehicle comes to a stop or the driver releases the brakes, or until other road, load, and vehicle conditions change the mode of operation.

This mode of operation, in which the deceleration switch 30 controls the brake release period, provides optimal lock control when the vehicle is under load and/or when the road surface has a high coefficient of friction.

In the second mode of operation, the brake release period is controlled by the cycle depth signal output of cycle depth integrator 32.

This mode usually has a medium road friction coefficient and/or
In relation to the vehicle load, the cycle depth during brake release tends to be deeper and longer than in the first mode of operation.

This mode is shown in FIGS. 3b and 3c, and when the wheel deceleration exceeds the reference deceleration at to and indicates the start of wheel lock, the deceleration switch 30 generates a control signal to stop the release prohibition signal and brake the vehicle. A release signal is generated and the brake is released in the same manner as in the first operation mode.

Similarly to the above, even after release, the wheels continue to decelerate due to the delay in the brake system (curve A1 cycle depth).

Due to the low coefficient of friction of the road surface and light loads, the cycle depth is generally larger and longer than with high coefficients of friction and high loads.

At tl, the cycle depth (curve A) exceeds the cycle depth reference value (curve D).

At time t2, the wheels stop decelerating because the brakes are released too little, and acceleration starts toward the vehicle speed.

In FIG. 3b, the wheel has a maximum acceleration that is less than the reference value 2g of the acceleration switch 360, and in FIG. 3D, the wheel has a maximum acceleration that is greater than the reference value 2g.

At time t3, the deviation of the wheel speed from the reference speed (curve B) at which the vehicle is decelerated by the reference value of the deceleration switch becomes zero, and the switch 30 stops the control signal.

However, at t3, the cycle depth is still greater than the cycle depth reference value (curve D) determined by the wheel speed, the deceleration amplifier 34 of FIG. 3b, and the acceleration switch 36 of FIG. 3c;
The brake release signal from comparator 40 is therefore connected.

In the second operating mode shown in FIG. 3b, the cycle depth becomes less than the cycle depth reference value at time t4, and the comparator 40 stops the brake release signal and reactivates the brake.

In the mode shown in FIG. 3c, the deviation of the wheel speed from the reference speed (curve C) decelerating at the reference deceleration of the deceleration amplifier 34 becomes zero at t4, and the output of the amplification device 34 becomes zero. drops to ground potential.

However, the acceleration switch 36 has an acceleration reference value of 2g? In response to the exceeded wheel positive acceleration, a portion of the cycle depth reference signal continues to be outputted via the gate 46.

Therefore, the cycle depth reference value does not change and the brake release signal of comparator 40 is maintained.

In FIG. 3, the cycle depth becomes less than the reference value at time t5, at which point the comparator 40 stops issuing the brake release signal and reactivates the brake.

When the brake release signal is stopped in FIG. 33, if the average wheel deceleration is less than or equal to the deceleration reference value of the cycle depth integrator 32, the cycle depth signal is reset to the ground potential.

The wheels are then accelerated and then begin to decelerate by applying the brakes, and this cycle repeats as described above until the vehicle comes to a stop, or until the mode is changed due to the driver's brake release command or other road, load, or vehicle conditions. be done.

The third cycle depth integrator controls the brake release period.
The second operating mode shown in Figures b and 3c provides optimal wheel lock control for moderate vehicle loads and/or road friction coefficients.

FIG. 3d shows a third mode of operation, in which the brake release period is controlled by a release inhibition circuit 38.

This mode is generally associated with conditions of light vehicle load and/or low coefficient of road friction, and the cycle depth during brake release is deeper and longer than in the first and second modes of operation.

As in the previous mode, the brake is released at time t.

It is initiated when the wheel deceleration exceeds the deceleration reference value of the deceleration switch 30, which generates a control signal to stop the release inhibit signal and generate a brake release signal.

At time tl, the cycle depth (curve A) exceeds the reference value (curve D).

At t2, due to the release of the brake, the wheels stop decelerating and start accelerating.

Due to the low friction coefficient and/or light load, the wheel positive acceleration is less than the acceleration switch 360 reference value of 2 g, but is greater than the possible acceleration reference value of the release prohibition circuit 38.

At t3V-, the deviation of the wheel speed from the reference speed (curve B), which is decelerated by the reference value of the deceleration switch 300, becomes zero, and the deceleration switch stops the control signal.

However, the cycle depth is determined by the wheel speed signal and the deceleration amplifier 34.
is still greater than the cycle depth reference value determined by , so the comparator 40 maintains the brake release signal.

The deviation of the wheel speed from the reference speed (curve C), which is decelerated by the deceleration reference value of the deceleration intensifier IJ device 34, becomes zero at t4, the output of the deceleration intensifier 34 decreases to the ground potential, and the wheel acceleration increases. Since the switch 360 reference value is less than 2g, the cycle depth reference value is reduced to the value determined by the wheel speed signal.

The cycle depth is greater than this reduced reference value.
Comparator 40 therefore holds the brake release signal.

At t5, the wheel acceleration becomes less than the acceleration reference value of the release inhibition circuit 38, indicating that the wheel speed has approached the vehicle speed.

Therefore, a release prohibition signal is sent to comparator 40, which stops the brake release signal and reactivates the brake.

The third operating mode shown in Figure 36 performs optimal wheel lock control under light vehicle loads and/or when the road surface has a low coefficient of friction, and complements the second and second operating modes to accommodate all vehicle loads and road surface conditions. Perform optimal wheel lock control.

During the three modes of wheel lock control, transistor 184 in integrator 32 is biased off during the brake release signal from comparator 40, ie during the brake release period.

Capacitor 1 precharged to the voltage across resistor 188
90 is discharged through resistor 188 during the same period at a rate related to the deceleration reference value provided when transistor 1840 is on.

When the brake release signal stops, the transistor 184 is again biased to the on state.

The current pulse supplied to the negative input of amplifier 192 for recharging capacitor 190 is
is always on during the brake release signal and the cycle depth signal is set to the value that would be obtained if the deceleration reference value supplied thereto was continuously added to the wheel acceleration signal.

If the average wheel deceleration is less than the reference deceleration provided during the ON state of transistor 1840, the cycle depth signal is set to ground potential on each 7" L/-K release signal termination.

However, if the average wheel deceleration is greater than the reference deceleration supplied during the on-state of transistor 184, then the reference deceleration should be obtained if the reference deceleration or vehicle acceleration signal is added continuously during the brake release period. A cycle depth signal is set to a positive level.

If the average wheel deceleration is continuously greater than the reference deceleration, the cycle depth signal is set to progressively higher levels;
This means that during the brake release period, the integrator output is resistor 244.
The cycle depth reference value supplied via the deceleration switch continues until the cycle depth reference value is reached, thereby holding the brake release signal after the control signal from the deceleration switch is stopped and ensuring that the wheel speed recovers towards the heavy speed. possible.

This condition occurs, for example, when the driver applies the brakes slowly on a road with a low coefficient of friction, so that the wheel cycle depth is similar to that on a road with a high coefficient of friction, and the system operates in the first operating mode. It can exist.

If the cycle depth signal has a sufficient value to maintain release even after the control signal has stopped, brake re-application is generally controlled as in the third mode, so that wheel speed can again increase to near vehicle speed.

(The cycle depth integrator avoids approaching a wheel lock condition that occurs when the wheels are decelerated beyond the maximum possible vehicle deceleration.)

The remainder of the circuit of Figures 2a and 2b is used for a self-monitoring circuit that commands brake application, inhibits brake release, and shuts off the lock control system if a fault is detected in the system.

Supervisory timer 50 receives current input to the negative input of amplifier 288 from output 1 drive/cutoff circuit 42 via line 293, diode 294, and resistor 296.

This current is provided by the circuit 42 from the Panteri voltage B+, resistor 280, and solenoid 44 when transistor 276 is in off-state near-flake operation and solenoid 44 is not shorted to ground or disconnected.

This current is too weak to excite the solenoid, but the timer 5
The bias current to the amplifier 288 via the zero resistor 292 is stronger, so if there is no other input at the positive input of the amplifier 292, the timer output should be held at ground potential.

Timer 50 also receives a current at the negative input of amplifier 288 that is proportional to the cycle depth during wheel lock control operation.

This current flows from cycle depth integrator 32 to line 298;
Supplied via resistor 300.296.

When brake release is initiated and transistor 276 is biased on or a short to ground or open circuit occurs in solenoid 44, current to timer 50 via line 293ff is stopped and the current through resistor 292 is turned off to the amplifier. The output of 288 changes positively at a rate determined as a function of the cycle depth related current value through line 298.

In the case of excessively long brake release periods, such as those involving increasing cycle depth, the output of timer 50 rises to the trigger level of supervisory comparator 54.

When the release is stopped or the solenoid 44 is shorted to ground or disconnected, the timer output returns to ground potential.

Further, a detector continuity monitoring circuit 48 that monitors the detectors 14 and 16 and generates a detector fault current when a disconnection fault is detected in any of them monitors the current and monitors the current in the amplifier 2 of the timer 50.
88 positive input.

The circuit 48 has an NPN transistor 302 whose collector is connected to the pantry voltage B+ through a resistor 304 and whose emitter is connected to the positive input of the amplifier 288 of the timer 50.

The non-grounded sides of detectors 14 and 16 are connected to resistors 308 and 3, respectively.
06 to the base of transistor 302.

In addition, a filter capacitor 3'IO is connected between the base and ground.
be established.

The base of transistor 302 is always near ground potential due to the low impedance of detector 14.160.

Therefore, if the detectors 14 and 16 are normal, the transistor 3
02 should be biased to the off state.

If one or both of the detectors 14, 16 is disconnected, the base bias of the transistor 302 is transferred from the regulated power supply Z+ to the resistors 76 and/or 94 and the resistors 306 and
or ) 308 , so that transistor 3302 is biased on to provide the detector fault current to the positive input of amplifier 288 of timer 50 .

This current, when added to the bias current passing through resistor 292, is greater than the negative input current of amplifier 288, so that the output of the amplifier will be positively integrated after a certain period of time and will be added to monitoring comparator 5.
4 trigger level is reached.

When the detector fault is corrected and the detector fault current ceases, the output of timer 50 returns to ground potential.

As described above, when the bunch lJt pressure B+ falls below the regulated voltage 2+, the power supply 52 supplies the power supply fault current via line 74 to the positive input of the amplifier 288.

This current acts similarly to the detector fault current and after a period of time the output of amplifier 288 becomes positive relative to the trigger level of monitor comparator 54.

When voltage B+ again rises above Z, the power supply fault current stops and the output of timer 50 returns to ground potential.

The output of timer 50 is provided via resistor 314 to the negative input of op amp 312 of comparator 54.

A bias current is also provided to the negative input via a resistor 316 connected to 2+.

A first feedback resistor 318 is connected between the amplifier 312, the output, and the positive input, and a second feedback resistor 320 is connected between the output and the positive input via a diode 322, and the anode of the diode is connected to the output side. reactor.

When the wheel lock control system generates a brake release signal, circuit 42 connects line 324 to diode 32.
Current is provided to the positive input of amplifier 312 through resistor 326 and resistor 320 connected to the cathode of amplifier 312.

The voltage on the cand side of the diode 322 is
and the voltage Z+ by a diode 327 provided between the voltage Z+ and the voltage Z+.

Current is supplied by the output drive and disconnect circuit 42 from the battery voltage B+ and a resistor 328 connected between it and line 324.

Line 324 is also connected to the 7L/V of transistor 266 so that a brake release signal is generated and transistor 266 is turned on from line 324 to comparator 54.
Stop the current supplied to the

Therefore, the current should only be supplied when the wheel lock control logic output is the brake application output (no brake release signal).

When there is no output from timer 50, the output is a brake activation signal and the current supplied to the positive input of amplifier 312 via line 324 and resistor 320 is thicker than the current from resistor 316 to the negative input. , and when the output is at a high level, the resistor 318, the diode 322, and the resistor 32
The circuit constants should be determined so that the sum of the positive input currents from the resistor 316 is greater than the negative input current from the resistor 316.

Thus, when the wheel lock control circuit is first activated and generates a brake activation signal, the output of amplifier 312 goes high, which latches the output high due to feedback through resistors 318 and 320.

This constant output is connected to transistor 26 via line 282.
8 to turn it on, thus allowing the output drive and disconnect circuit 42 to release the brake during the brake release period determined by the cycle depth comparator 40.

Comparator 54 equal to the difference between the feedback current to the positive input of amplifier 312 and the bias current to the negative input via resistor 316
Only when a current greater than the 0 trigger level is supplied from the timer 50 does the amplifier 312 of the comparator 54 move from its normally high state to ground potential.

The timer 50 performs integration after detecting a failure or brake release and supplies the above value after a certain period of time.

When the output of the timer 50 reaches the trigger level of the comparator 54, the output of the amplifier 312 reaches the ground potential, which is used as a cutoff signal to output drive the transistor 26 of the cutoff circuit 34.
8 to the off state and brake release solenoid 4
4 to prevent brake release by the wheel lock control system.

The cutoff signal is output by the comparator 54 during the period when the output of the timer 50 is above the trigger level of the comparator 54.

The output of the comparator 54 when the fault stops and the output of the timer 50 falls below the trigger level of the comparator 54 tb &!
It depends on whether the wheel lock control system outputs a brake release signal or not.

When the system is in the brake application mode, a fault outage and a fall of the timer 50 output below the trigger level of the comparator 54 causes the amplifier 31 to be output from circuit 42 via line 324.
Since no current is supplied to the positive input of the comparator 54, the output of the comparator 54 returns to the positive voltage level again, stopping the interrupt signal.

However, if the fault stops while the lock control system outputs a brake release signal and is in brake release mode, there is no current supply to the positive input of amplifier 312, and resistor 3
The amplifier output is kept at ground potential by the bias current from 16.

Therefore, the comparator is launched low to continue the shutoff signal. Therefore, the output drive and shutoff circuit 42 is unable to release the brake during the brake release signal from the cycle depth comparator 40.

When the brake release signal from the lock control circuit ceases, a current supplied from line 324 to amplifier 312 causes the break signal to cease.

The comparator 54 thus provides a non-launching shutdown of the lock control system for the duration of the fault if the fault occurs during the brake operating mode, and also provides a non-launching shutdown of the lock control system for the duration of the fault if the fault occurs even momentarily and co-exists with the brake release signal. latching of the lock control system for the duration of the condition or brake release signal, whichever is longer.

The detector dynamic monitoring circuit 58 is a PNP) transistor 330.
．． It has 332.

The speed signal from the tacho generator 22 is transmitted to the transistor 33.
0 and to each emitter of transistors 330 and 332 through a diode 334 and a resistor 336.

The speed signal from the tacho generator 24 is transmitted to the transistor 33.
20 base and via a diode 338 and a resistor 336 to each emitter of transistors 330 and 332.

The emitter is also grounded via resistor 340.

Diodes 334 and 338 are formed by resistors 336 and 340 and provide the maximum wheel speed signal to the voltage divider.

When the difference between the high and low wheel speeds exceeds a predetermined amount, such as 17 miles per hour, the low wheel speed base biases the transistor 330 or 332 on and outputs the cycle depth comparator 40 via line 342. Send a current to the input to generate a brake release signal and energize the solenoid 44.

After the timer 50 expires, the comparator 54 generates a cutoff signal to cut off the lock control circuit.

Thus, the system may be shut down in response to failures other than continuity of detector 14 or 16.

When a cut-off signal occurs, the driver is notified of the malfunction by a visual warning.

The fault signal is applied to the NPN of lamp circuit 56 through resistor 346.
Be applied to the base of transistor 3440.

Its collector is connected to the base of a common emitter Darlington transistor 348.

The collectors of transistors 344 and 348 are connected through resistors 352 and 354, respectively, to a lamp 350 whose other terminals are connected to battery voltage B+.

When the cutoff signal is generated, the transistor 344 which is always on is cut off, and the transistor 348 is kept on and the lamp 3 is turned on.
50 is lit to indicate an alarm.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a preferred embodiment of the wheel lock control system of the present invention. 2a and 2b are simplified electrical circuit diagrams of the wheel lock control system of FIG. 1; FIG. 3a, 3b, 3c, and 3a are graphs showing three operating modes of the wheel lock control system shown in FIGS. 1 and 2. FIG. Explanation of symbols of main parts, 10.12...Wheels, 14.
16... Speed detector, 18.20... Rectangular amplifier, 22.24... Wolfberry generator, 26... Speed selector, 34... Deceleration amplifier, 36...・Acceleration switch, 46...Gate, 38・Second release prohibition circuit, 30...
・Deceleration switch, 32...Cycle depth integrator, 40
... Cycle depth comparator, 42 ... Solenoid drive, cutoff circuit, 44 ... Solenoid, 48 ... Detector monitoring circuit, 50 ... Timer, 52 ... Power supply, 54
. . . Comparator, 58 . . . Dynamic monitoring circuit, 56 . . . Lamp drive circuit and lamp indicator.

Claims (1)

[Scope of Claims] 1. Means for supplying a wheel speed signal indicative of wheel speed; and a means for responding to the wheel speed signal and being initiated when the rate of change in wheel speed exceeds a predetermined deceleration threshold indicating the start of wheel lock. a deceleration switch for supplying a control signal, means for supplying an acceleration signal indicative of wheel acceleration in response to the speed signal, means for supplying a deceleration reference signal indicative of the lowest vehicle deceleration, and an acceleration signal and a deceleration reference. a vehicle lock control system for a vehicle having braked wheels, the means for providing a deceleration reference signal including means for terminating the deceleration reference signal during brake release; The output is a cycle depth signal which is a composite signal consisting of a first part indicating the amount by which the time integral of the deceleration reference signal exceeds the wheel speed during braking and a second part which is the integral value of the wheel acceleration during brake release. , the system further includes a control means responsive to the control signal and the cycle depth signal to cause the cycle depth signal to decycle during the period of the control signal, and a cycle depth signal output value of the integrating means in response to brake reactivation. means for setting the deceleration reference signal to a cycle depth signal value that would be obtained if the deceleration reference signal were successively summed with the acceleration signal, the cycle depth signal being a wheel deceleration signal whose average wheel deceleration exceeds the maximum possible vehicle deceleration. When the brake is released and the operating length is repeated repeatedly when the brake is approaching the locked state, the brake is released and the operating length increases above the reference value to maintain the wheel brake in the released state and allow the wheel to accelerate toward the vehicle speed, thereby causing the wheel lock phenomenon. A wheel lock control system that prevents. 2. The system according to claim 1, wherein the coupling means supplies the acceleration signal and the deceleration reference signal to the summing junction 182, and supplies from the junction an output signal which is an algebraic representation of both signals, and integrating means 192. , 198 are connected to the junction for integrating the output signal to provide a cycle depth signal and for providing a deceleration reference signal 184. 186, 188, a series circuit including a switch means 184, and a capacitor 190 connected in parallel to the resistor, the switch means being in a non-conducting state when the brake is released and being in a conductive state when the brake is applied, which is connected to the control means. the capacitor is charged during braking and discharged through the resistor at a rate related to the deceleration reference signal during brake release, so that upon biasing the switch means into conduction a pulse is applied to the summing junction and the integration means A tossle wheel lock control system characterized in that the pulse depth signal output value is set to the cycle depth signal value that would be obtained if the switch means were continuously biased conductive and provided a deceleration reference signal. 3. The system according to claim 1, wherein the control means 40 is responsive to the control signal and the cycle depth signal, and during the period of the control signal and the cycle depth signal is greater than all values of the cycle depth signal during braking operation. A cycle depth integrator 320 that has a first level and during brake release has a lower second level that releases the brakes for a period exceeding a reference value such that the deceleration switch itself initiates brake release and is responsive to the wheel speed signal. Means 178°180
provides an acceleration signal indicating acceleration or deceleration of the wheel, and the cycle depth signal is greater than the second level of the stop hind leg reference value of the control signal from the deceleration switch 30 in a first range of road friction coefficient and wheel load conditions. The cycle depth signal has a lower value so that the deceleration switch provides optimal wheel lock control only in the first range of conditions, and the cycle depth signal is lower than the deceleration switch in the second range of road coefficient and wheel load conditions. the stop hindlimb reference value of the control signal has a value higher than the second level, so that the cycle depth integrator extends the brake release period initiated by the deceleration switch to provide optimal wheel lock control under the second range of conditions; , the means 184-190 for responding to brake re-operation are integral means 1
92°198, so that the cycle depth signal supplied from this has the same value as the cycle depth signal that would be obtained if the deceleration reference signal was successively summed with the acceleration signal, and the cycle depth signal value is the average When the wheel deceleration exceeds the maximum possible vehicle deceleration and indicates that the wheels are close to a locked state, the control signal from the deceleration switch is generated when the brake reaches a value higher than the second level of the reference value while repeating brake release and activation. A wheel lock control system that prevents wheel locking by extending brake release after stopping and allowing the wheels to accelerate toward the vehicle speed. 4. In the system according to claim 1, the deceleration switch 30 is activated in response to the wheel speed signal when the wheel speed change rate exceeds a predetermined deceleration threshold indicating the start of wheel lock, and the wheel speed is set to a predetermined value. The deceleration amplifier 34 generates a control signal that is stopped when the wheel deceleration is again equal to the first reference wheel speed decelerating at the threshold deceleration, and the deceleration amplifier 34 is activated when the wheel deceleration exceeds the reference deceleration level that is less than the predetermined threshold speed. and the acceleration switch 36 responds to the wheel speed by supplying a first reference signal to the wheel speed and stopping the first reference signal when the wheel speed is again equal to a second reference wheel speed having a deceleration equal to the reference deceleration level. means 14-28 for providing a second reference signal during a period in which the rate of change of wheel speed is less than a particular positive acceleration level; The means 46 adds the greater of the first and second reference signals to the third reference signal to provide a cycle depth reference signal, and the release prohibition switch 38 is activated when the control signal is absent and when the wheel acceleration is at a predetermined low level. If the sum of the cycle depth signal and the control signal is greater than the sum of the cycle depth reference signal and the release prohibition signal, then The brake release inhibit signal is greater than the maximum value of the cycle depth signal, and the control signal is greater than the maximum value of the cycle depth reference signal, so that the deceleration switch itself initiates the brake release signal. is possible, and the cycle depth signal has a value indicative of the wheel speed change during the brake release signal period, and the brake control means 42.
44 is responsive to a brake release signal to release the brakes during that period, a deceleration switch controls the brake release period during a first mode of operation of the wheel lock control system, and a cycle depth integrator controls the brake release period during a second mode of operation of the system. A five-wheel lock control system, wherein a brake release period is controlled during an intermediate brake release period, and a release prohibition switch controls a brake release period during a third operating mode of the system. 5. In the system according to claim 1, 2 or 3, the control circuit means 30, 32゜38.40
．． 42 is responsive to the wheel speed signal to provide a brake release signal when the wheel speed signal characteristic indicates a wheel lock start condition, the brake control means 44 is responsive to the brake release signal and releases the brake during that period; A fault monitoring and disconnection circuit is provided in the system, which circuit is provided with means 48, 50, 52 for generating a fault signal in response to the detection of a fault, and in response to the fault signal and the brake release signal, the circuit is activated solely by the fault signal. and terminates only when both the fault signal and the brake release signal stop; therefore, during a temporary period other than the brake release signal period, and if the fault signal and the brake release signal coexist even momentarily, either of the two signals logic means 54 for providing an inhibit logic signal lasting for a longer period; and means 2 for inhibiting the brake control means from reacting to the brake release signal in response to the inhibit logic signal;
68, so that the brake control means is capable of controlling both signals during the continuation of a temporary fault condition that occurs during a period other than the brake release signal period and when the fault signal coexists at least momentarily with the brake release signal. A wheel lock control system that does not release the brakes during the longest period of time. 6. In the system according to claim 5, the logic means includes means 316 for supplying the reference signal, comparison means 312 for supplying the prohibition logic signal as described above, and a means 312 connected to the comparison means for providing the prohibition logic signal in the absence of the prohibition logic signal. means 320 for providing a feedback signal of a value less than the sum of the fault signal and the reference signal during the interval and greater than the reference signal; and responsive to control circuit means 320 for providing a brake application logic signal in the absence of the brake release signal. means 280, 44, 293 for comparing the fault signal, the reference signal, the feedback signal and the brake operation logic signal, the signal having a value less than the sum of the fault signal and the reference signal and greater than the reference signal; In response to the fault signal and the brake release logic signal, the sum of the fault signal and the reference signal exceeds either the feedback signal or the brake release logic signal, so that the inhibit logic signal is initiated only by the fault signal and the fault signal and the brake release signal are during a temporary failure that occurs during a period other than the brake release signal period, and when the failure signal and the brake release signal coexist at least momentarily. A wheel lock control system characterized in that it continues for the longer of: 7. In the system according to claim 1, 2 or 3, the control circuit means 30, 32゜38.40
．． 42 is responsive to the wheel speed signal to provide a brake release signal when the wheel speed signal characteristic indicates a wheel lock start condition, the brake control means 44 is responsive to the brake release signal and releases the brake during that period; A fault monitoring and shutoff circuit is provided in the system, which circuit includes a timing circuit 50 and a plurality of means 48, 50, 52 for respectively transmitting a fault signal to a timer circuit in response to fault detection;
means 293 for providing a brake release period signal to a timer circuit during the period of the brake release signal, the timer circuit providing a master fault signal if the fault signal or brake release period signal is present for a specified period of time; further comprising means for providing a reference signal, a comparison means 312 for providing an inhibit logic signal, and a feedback signal connected to the comparison means to provide a feedback signal less than the sum of the master fault signal and the reference signal and greater than the reference signal in the absence of the inhibit logic signal; means 320 for;
Means 280 responsive to the control circuit means for providing a brake activation logic signal less than the sum of the master fault signal and the reference signal and greater than the reference signal in the absence of the brake release signal.
．． 44,293, the comparison means is responsive to the master fault signal, the reference signal, the feedback signal and the brake operation logic signal to determine whether the sum of the reference signal and the master fault signal is greater than either the feedback signal or the brake operation logic signal. Provides an inhibit logic signal during the brake release signal period 1, so that the signal is only initiated by the master fault signal and stopped only when both the fault signal and the brake release signal stop, thus providing a temporary fault that occurs during a period other than the brake release signal period. and, if the fault signal and the brake release signal coexist at least momentarily, only during the longer of the two signals, and in response to the inhibit logic signal, the brake control means releases the brake. comprising means 268 for prohibiting responding to the signal;
As a result, the brake control means is subject to temporary fault conditions that occur during periods other than the brake release signal period and, if the fault signal coexists at least momentarily with the brake release signal, during the longer period of either of the two signals. Wheel lock control system that does not release the brakes.