Single Channel Roll Stability System
First Claim
1. A method of assessing whether a vehicle equipped with a plurality of wheel brakes is about to overturn, the vehicle being equipped with a single brake pressure modulator arranged to control actuation of the vehicle brakes, comprising the acts of:
- determining a lateral acceleration of the vehicle;
determining a rotational wheel speed of the vehicle wheels;
when the lateral acceleration exceeds a predetermined threshold, conducting a rotational wheel speed change test, wherein the test includesif the vehicle is not being braked, applying a brake pressure to the vehicle brakes with the single brake pressure modulator, orif the vehicle is being braked, lowering a brake pressure being applied by the single brake pressure modulator;
after applying or lowering the brake pressure, monitoring the wheel speed behavior of the vehicle wheels on an inside side of the vehicle, said inside side being the side facing away from the lateral acceleration direction;
restoring brake pressure to the brake pressure existing before the rotational wheel speed test; and
determining based on monitored wheel speed behavior following the restoring brake pressure step whether the vehicle is about to overturn.
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Accused Products
Abstract
A method and system for assessing and preventing overturn of a vehicle, the method and system being particularly suitable for use with commercial vehicles with brake systems typically used in North America, wherein a vehicle equipped with single brake pressure modulator is controlled to increase or decrease brake pressure, depending on braking state, to test vehicle wheel speed by response. If the vehicle wheel speed response indicates the inside wheels of the vehicle are off the ground or only lightly loaded, it may be assumed that the vehicle is approaching overturning. A braking intervention may be then executed by the single brake pressure modulator to prevent the incipient overturn event.
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Citations
18 Claims
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1. A method of assessing whether a vehicle equipped with a plurality of wheel brakes is about to overturn, the vehicle being equipped with a single brake pressure modulator arranged to control actuation of the vehicle brakes, comprising the acts of:
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determining a lateral acceleration of the vehicle; determining a rotational wheel speed of the vehicle wheels; when the lateral acceleration exceeds a predetermined threshold, conducting a rotational wheel speed change test, wherein the test includes if the vehicle is not being braked, applying a brake pressure to the vehicle brakes with the single brake pressure modulator, or if the vehicle is being braked, lowering a brake pressure being applied by the single brake pressure modulator; after applying or lowering the brake pressure, monitoring the wheel speed behavior of the vehicle wheels on an inside side of the vehicle, said inside side being the side facing away from the lateral acceleration direction; restoring brake pressure to the brake pressure existing before the rotational wheel speed test; and determining based on monitored wheel speed behavior following the restoring brake pressure step whether the vehicle is about to overturn. - View Dependent Claims (2, 3)
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4. A method of preventing overturning of a vehicle equipped with a plurality of wheel brakes, the vehicle being equipped with a single brake pressure modulator arranged to control actuation of the vehicle brakes, comprising the acts of:
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determining a lateral acceleration of the vehicle; determining a rotational wheel speed of the vehicle wheels; when the lateral acceleration exceeds a predetermined threshold, conducting a rotational wheel speed change test, wherein the test includes if the vehicle is not being braked, applying a brake pressure to the vehicle brakes with the single brake pressure modulator, or if the vehicle is being braked, lowering a brake pressure being applied by the single brake pressure modulator; after applying or lowering the brake pressure, monitoring the wheel speed behavior of the vehicle wheels on an inside side of the vehicle, said inside side being the side facing away from the lateral acceleration direction; restoring brake pressure to the brake pressure existing before the rotational wheel speed test; determining based on monitored wheel speed behavior following the restoring brake pressure step whether the vehicle is about to overturn; and applying the vehicle brakes to decrease vehicle speed when it is determined that the vehicle is about to overturn. - View Dependent Claims (5, 6)
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7. A vehicle overturn assessment system for assessing whether a vehicle equipped with a plurality of wheel brakes is about to overturn, comprising:
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a vehicle lateral acceleration sensor; a plurality of vehicle wheel speed sensors for sensing rotational wheel speed of at least one wheel on each lateral side of a vehicle; a single brake pressure modulator arranged to control actuation of the vehicle wheel brakes; and a control unit, wherein the control unit is programmed to monitor signals generated by the lateral acceleration sensor and the wheel speed sensors, monitor whether the single brake pressure modulator is applying braking pressure, and command the single brake pressure modulator to apply braking pressure, and wherein the control unit is programmed to assess whether a vehicle overturn event is about to occur by determining whether a lateral acceleration sensed by the lateral acceleration sensor exceeds a predetermined threshold, determining the rotational wheel speed of at least the at least one wheel on each lateral side of a vehicle, conducting a rotational wheel speed change test when the lateral acceleration exceeds the predetermined threshold, wherein the test includes if the vehicle is not being braked, applying a brake pressure to the vehicle brakes with the single brake pressure modulator, or if the vehicle is being braked, lowering a brake pressure being applied by the single brake pressure modulator, after applying or lowering the brake pressure, monitoring the wheel speed behavior of the vehicle wheels on an inside side of the vehicle, said inside side being the side facing away from the lateral acceleration direction; restoring brake pressure to the brake pressure existing before the rotational wheel speed test; and determining based on monitored wheel speed behavior following the restoring brake pressure step whether the vehicle is about to overturn. - View Dependent Claims (8, 9)
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10. A vehicle overturn prevention system for assessing and preventing the overturn of a vehicle equipped with a plurality of wheel brakes, comprising:
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a vehicle lateral acceleration sensor; a plurality of vehicle wheel speed sensors for sensing rotational wheel speed of at least one wheel on each lateral side of a vehicle; a single brake pressure modulator arranged to control actuation of the vehicle wheel brakes; and a control unit, wherein the control unit is programmed to monitor signals generated by the lateral acceleration sensor and the wheel speed sensors, monitor whether the single brake pressure modulator is applying braking pressure, and command the single brake pressure modulator to apply braking pressure, and wherein the control unit is programmed to assess and prevent a vehicle overturn event by determining whether a lateral acceleration sensed by the lateral acceleration sensor exceeds a predetermined threshold, determining the rotational wheel speed of at least the at least one wheel on each lateral side of a vehicle, conducting a rotational wheel speed change test when the lateral acceleration exceeds the predetermined threshold, wherein the test includes if the vehicle is not being braked, applying a brake pressure to the vehicle brakes with the single brake pressure modulator, or if the vehicle is being braked, lowering a brake pressure being applied by the single brake pressure modulator, after applying or lowering the brake pressure, monitoring the wheel speed behavior of the vehicle wheels on an inside side of the vehicle, said inside side being the side facing away from the lateral acceleration direction; restoring brake pressure to the brake pressure existing before the rotational wheel speed test; determining based on monitored wheel speed behavior following the restoring brake pressure step whether the vehicle is about to overturn; and commanding the single brake pressure modulator to apply the vehicle brakes to decrease vehicle speed when it is determined that the vehicle is about to overturn. - View Dependent Claims (11, 12)
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13. A control unit for a vehicle overturn assessment system for assessing whether a vehicle equipped with a plurality of wheel brakes is about to overturn, wherein:
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the control unit is arranged to communicate with a vehicle lateral acceleration sensor, a plurality of vehicle wheel speed sensors for sensing rotational wheel speed of at least one wheel on each lateral side of a vehicle and a single brake pressure modulator arranged to control actuation of the vehicle wheel brakes, and the control unit is programmed to monitor signals generated by the lateral acceleration sensor and the wheel speed sensors, monitor whether the single brake pressure modulator is applying braking pressure, command the single brake pressure modulator to apply braking pressure, and to assess whether a vehicle overturn event is about to occur by determining whether a lateral acceleration sensed by the lateral acceleration sensor exceeds a predetermined threshold, determining the rotational wheel speed of at least the at least one wheel on each lateral side of a vehicle, conducting a rotational wheel speed change test when the lateral acceleration exceeds the predetermined threshold, wherein the test includes if the vehicle is not being braked, applying a brake pressure to the vehicle brakes with the single brake pressure modulator, or if the vehicle is being braked, lowering a brake pressure being applied by the single brake pressure modulator, after applying or lowering the brake pressure, monitoring the wheel speed behavior of the vehicle wheels on an inside side of the vehicle, said inside side being the side facing away from the lateral acceleration direction; restoring brake pressure to the brake pressure existing before the rotational wheel speed test; and determining based on monitored wheel speed behavior following the restoring brake pressure step whether the vehicle is about to overturn. - View Dependent Claims (14, 15)
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16. A vehicle overturn assessment system for assessing whether a vehicle equipped with a plurality of wheel brakes is about to overturn, comprising:
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a vehicle lateral acceleration sensor; a plurality of vehicle wheel speed sensors for sensing rotational wheel speed of at least one wheel on each lateral side of a vehicle; a single brake pressure modulator arranged to control actuation of all the vehicle brakes on at least one vehicle axle; and a control unit, wherein the control unit is programmed to monitor signals generated by the lateral acceleration sensor and the wheel speed sensors, monitor whether the single brake pressure modulator is applying braking pressure, and command the single brake pressure modulator to apply braking pressure, and wherein the control unit is programmed to assess whether a vehicle overturn event is about to occur by determining whether a lateral acceleration sensed by the lateral acceleration sensor exceeds a predetermined threshold, determining the rotational wheel speed of at least the at least one wheel on each lateral side of a vehicle, conducting a rotational wheel speed change test when the lateral acceleration exceeds the predetermined threshold, wherein the test includes if the vehicle is not being braked, applying a brake pressure to the vehicle brakes with the single brake pressure modulator, or if the vehicle is being braked, lowering a brake pressure being applied by the single brake pressure modulator, after applying or lowering the brake pressure, monitoring the wheel speed behavior of the vehicle wheels on an inside side of the vehicle, said inside side being the side facing away from the lateral acceleration direction; restoring brake pressure to the brake pressure existing before the rotational wheel speed test; and determining based on monitored wheel speed behavior following the restoring brake pressure step whether the vehicle is about to overturn. - View Dependent Claims (17, 18)
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Specification