WHEEL SUSPENSION CONTROL SYSTEM FOR A VEHICLE AND A METHOD OF CONTROLLING A SUSPENSION DEVICE

Abstract

The invention relates to a wheel suspension control system for a vehicle. The system comprises a suspension device, a wheel end bearing, at least one vibration sensor and a processing circuitry. The vibration sensor is provided at or in the wheel end bearing for measuring vibrations propagated from the road wheel to the wheel end bearing when the road wheel travels on a road having surface variations, wherein the vibration sensor is configured to transmit measurement signals representing the measured vibrations. The processing circuitry is configured to receive the transmitted measurement signals and to control at least one suspension parameter of the suspension device based on the received measurement signals. The invention also relates to a vehicle and to a method for controlling a suspension device.

Claims

1. A wheel suspension control system for a vehicle, comprising: a suspension device operatively connectable to a wheel axle carrying a road wheel, a wheel end bearing operatively connectable to the road wheel, at least one vibration sensor provided at the wheel end bearing for measuring vibrations propagated from the road wheel to the wheel end bearing when the road wheel travels on a road having surface variations, wherein the vibration sensor is configured to transmit measurement signals representing the measured vibrations, and a processing circuitry configured to receive the transmitted measurement signals, wherein the processing circuitry is configured to control at least one suspension parameter of the suspension device, such as stiffness, damping and/or ride height, based on the received measurement signals, wherein the wheel end bearing comprises an inboard bearing and an outboard bearing, wherein the vibration sensor is located at the inboard bearing, and wherein the wheel suspension control system further comprises a central wheel support member such as a spindle or a steering knuckle, wherein the vibration sensor is located between the inboard bearing and the central wheel support member.

2. The wheel suspension control system claim 1, wherein the vibration sensor is spaced apart from the suspension device.

3. (canceled)

4. The wheel suspension control system of claim 2, wherein the vibration sensor is located on an inboard side of the inboard bearing.

5. (canceled)

6. The wheel suspension control system of claim 1, wherein the suspension device comprises an air suspension, such as including a bellows, wherein the processing circuitry is configured to adjust the air pressure in the suspension device based on the received measurement signals.

7. The wheel suspension control system of claim 1, wherein the suspension device comprises a shock absorber, wherein the shock absorber comprises a cylinder in which hydraulic fluid is housed and a piston movable inside the cylinder, wherein the piston is provided with at least one hole and/or valve defining an opening area allowing hydraulic fluid to pass through the piston, wherein the processing circuitry is configured to adjust the damping coefficient of the shock absorber, such as by adjusting the opening area, based on the received measurement signals.

8. The wheel suspension control system of claim 1, wherein the vibration sensor comprises at least one accelerometer.

9. The wheel suspension control system of claim 1, wherein the processing circuitry is configured to adjust the vehicle speed, by controlling a propulsion unit of the vehicle, based on the received measurement signals.

10. A vehicle comprising the wheel suspension control system of claim 1, wherein the vehicle further comprises a wheel axle carrying a road wheel, wherein the suspension device is operatively connected to the wheel axle, wherein the wheel end bearing is operatively connected to the road wheel.

11. A method of controlling a suspension device connected to a wheel axle carrying a road wheel, comprising: providing at least one vibration sensor at a wheel end bearing connected to the road wheel, wherein the wheel end bearing comprises an inboard bearing and an outboard bearing, wherein the vibration sensor is provided between the inboard bearing and a central wheel support member such as a spindle or a steering knuckle, measuring, by means of the vibration sensor, vibrations propagated from the road wheel to the wheel end bearing when the road wheel travels on a road having surface variations, transmitting measurement signals representing the measured vibrations, receiving, by a processing circuitry, the transmitted measurement signals, and controlling, by the processing circuitry, at least one suspension parameter of the suspension device, such as stiffness, damping and/or ride height of the suspension device, based on the received measurement signals.

12. The method of claim 11, wherein the suspension device comprises an air suspension, such as including a bellows, wherein the method comprises: adjusting, by means of the processing circuitry, the air pressure in the suspension device based on the received measurement signals.

13. The method of claim 1, wherein the suspension device comprises a shock absorber, wherein the shock absorber comprises a cylinder in which hydraulic fluid is housed and a piston movable inside the cylinder, wherein the piston is provided with at least one hole and/or valve defining an opening area allowing hydraulic fluid to pass through the piston, wherein the method comprises: adjusting, by means of the processing circuitry, the damping coefficient of the shock absorber, such as by adjusting the flow opening area, based on the received measurement signals.

14. The method of claim 11, comprising: adjusting, by means of the processing circuitry, the vehicle speed, by controlling a propulsion unit of the vehicle, based on the received measurement signals.

15. The method claim 11 for use in a wheel suspension control system for a vehicle, the wheel suspension control system comprising: a suspension device operatively connectable to a wheel axle carrying a road wheel, a wheel end bearing operatively connectable to the road wheel, at least one vibration sensor provided at the wheel end bearing for measuring vibrations propagated from the road wheel to the wheel end bearing when the road wheel travels on a road having surface variations, wherein the vibration sensor is configured to transmit measurement signals representing the measured vibrations, and a processing circuitry configured to receive the transmitted measurement signals, wherein the processing circuitry is configured to control at least one suspension parameter of the suspension device, such as stiffness, damping and/or ride height, based on the received measurement signals, wherein the wheel end bearing comprises an inboard bearing and an outboard hearing, wherein the vibration sensor is located at the inboard bearing, and wherein the wheel suspension control system further comprises a central wheel support member such as a spindle or a steering knuckle, wherein the vibration sensor is located between the inboard bearing and the central wheel support member.

16. A computer program comprising program code means for performing the steps of claim 11 when the program is run on a computer.

17. A computer readable medium carrying a computer program comprising program code means for performing the steps of claim 11 when the program product is run on a computer.

18. A processing circuitry for controlling a suspension parameter of a suspension device, the processing circuitry being configured to perform the steps of the method according to claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

[0056] In the drawings:

[0057] FIG. 1 illustrates a vehicle, in accordance with at least one exemplary embodiment of the invention.

[0058] FIG. 2 illustrates a wheel suspension control system in accordance with at least one exemplary embodiment of the invention, provided at a wheel end assembly.

[0059] FIG. 3 is a schematic illustration of a method in accordance with at least one exemplary embodiment of the invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

[0060] FIG. 1 illustrates a vehicle 1, in accordance with at least one exemplary embodiment of the invention. Although the vehicle 1 is illustrated in the form of a truck, other types of vehicles, such as busses, construction equipment, trailers or passenger cars may be provided in accordance with the invention.

[0061] The truck (vehicle) comprises a cab 2 in which a driver may operate the vehicle 1. The vehicle 1 comprises a number of road wheels 4, herein illustrated as two pairs of wheels, however in other embodiments there may be a different number of wheels, such as three pairs, four pairs or more. The rotation of the wheels 4 is facilitated by means of wheel end bearings (not shown in FIG. 1). The vehicle comprises 1 a wheel end assembly in which such a wheel end bearing is included, which wheel end assembly will be further discussed in connection with FIG. 2.

[0062] FIG. 1 illustrates that for each road wheel 4 a suspension device 6 is operatively connected to a wheel axle carrying the road wheel 4. The suspension device 6 is here illustrated as an air suspension such as including a bellows. However, the general inventive concept is applicable to other suspension devices as well, such as shock absorbers. A vibration sensor 8, such as an accelerometer, is schematically illustrated. It is provided at or in the wheel end bearing and configured to communicate with a processing circuitry (not shown in FIG. 1). The processing circuitry is configured to receive measurement signals (by wire or wirelessly) transmitted from the vibration sensor 8, and configured to control a suspension parameter of the suspension device 6, based on the received measurement signals.

[0063] The processing circuitry may include a microprocessor, microcontroller, programmable digital signal processor or another programmable device. The processing circuitry may also, or instead, include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. Where the processing circuitry includes a programmable device such as the microprocessor, microcontroller or programmable digital signal processor mentioned above, the processor may further include computer executable code that controls operation of the programmable device.

[0064] FIG. 2 illustrates a wheel suspension control system 100 in accordance with at least one exemplary embodiment of the invention, provided at a wheel end assembly 10. The wheel suspension control system 100 may suitably be implemented in a vehicle such as the vehicle illustrated in FIG. 1. The wheel end assembly 10 comprises a wheel end hub 12, which is configured to receive and hold a road wheel (not illustrated in FIG. 2). The wheel end hub 12 is rotationally mounted to a central wheel support member 14 via a wheel end bearing 16.

[0065] In FIG. 2 the central wheel support member 14 has been illustrated in the form of a steering knuckle, which may typically be provided at the front wheels of a vehicle. The knuckle is solid and used for non-driven wheels. However, it should be understood that the inventive principle could also be used in relation to a wheel support member in the form of a hollow spindle. A hollow/tubular spindle may typically be provided at the rear wheels of a vehicle and is used in connection with driven wheels. Normally, a drive shaft or axle extends through the spindle and is fixed to the outside of the wheel end hub for propulsion of the wheel.

[0066] The wheel end bearing 16 comprises an inboard bearing 18 and an outboard bearing 20, each of which is concentrically arranged around the central wheel support member 14. Of the two, it is the inboard bearing 18 which is configured to be located closest to a central longitudinal axis of the vehicle. Conversely, of the two, it is the outboard bearing 20 which is configured to be located furthest away from the central longitudinal axis of the vehicle.

[0067] The outboard bearing 20 comprises an inner-race forming part 22 and an outer race-forming part 24. The outboard bearing 20 also comprises roller elements 26 accommodated between the inner race-forming part 22 and the outer race-forming part 24. The roller elements 26 may suitably be circumferentially separated from each other by a cage having individual holes for each roller element. The relative motions of the inner and outer race-forming parts 22, 24 causes the roller elements 26 to roll with very little rolling resistance. The inner race-forming part 22 may also be referred to as an inner ring and the outer race-forming part 24 may also be referred to as an outer ring. In a similar way, the inboard bearing 18 comprises roller elements accommodated between an inner race-forming part 22′ and an outer race-forming part 24′.

[0068] The outboard bearing 20 has an outboard periphery 28 intended to face away from the central longitudinal axis of the vehicle and an inboard periphery 30 intended to face towards the central longitudinal axis of the vehicle.

[0069] A lock washer 31 is provided at the outboard periphery 28 of the inner-race-forming part 22. A hub nut 32, which comprises an inner threading is mounted to the central wheel support member 14, which has corresponding outer threading, allowing the hub nut 32 to be threaded onto the central wheel support member 14. The hub nut 32 is tightened to come into contact with a lock washer 31, thus arranged between the hub nut 32 and the inner race-forming part 22, in particular with the outboard periphery 28 of the inner race-forming part 22.

[0070] In its turn, the inner race-forming part 22 of the outboard bearing 20 (and similarly the inner race-forming part 22′ of the inboard bearing 18) is mounted to the central wheel support member 14.

[0071] The wheel end bearing 16 forms part of the wheel suspension control system 100. The wheel suspension control system 100 also comprises a vibration sensor 8 (such as the one illustrated in FIG. 1) provided at or in the wheel end bearing 16, attached to a surface of the wheel end bearing 16. The vibration sensor 8 is herein illustrated as extending circularly around the support member 14, however, in other exemplary embodiments the vibration sensor may be limited to one part of the circumference of the support member 14. In some exemplary embodiments, further vibration sensors may be provided. The vibration sensor 8 measures vibrations propagating from the road wheel to the wheel end bearing 16 when the road wheel travels on a road having surface variations. The vibration sensor 8 is configured to transmit measurement signals representing the measured vibrations.

[0072] The wheel suspension control system 100 further comprises a processing circuitry 40 configured to receive the transmitted measurement signal. The wheel suspension control system 100 further comprises a schematically depicted suspension device 42. The suspension device 42 may be in the form of an air suspension as exemplified by the suspension device 6 in FIG. 1, or it may be a hydraulic suspension. For instance, the suspension device 42 may be may be a shock absorber. Furthermore, the wheel suspension control system 100 may comprise more than one suspension device 42.

[0073] Based on the measurement signals received from the vibration sensor 8, the processing circuitry 40 is configured to control at least one suspension parameter of the suspension device 42 (and any other suspension device comprised in the wheel suspension control system 100). The suspension parameter may for instance be stiffness, damping, ride height, etc.

[0074] The processing circuitry 40 may include various control units, such as a sensor control unit receiving the measurement signals and then transmitting a command signal to a suspension control unit configured to adjust the suspension parameter.

[0075] The vibration sensor 8 is spaced apart from the suspension device 42, thus other vibrations than road vibrations, which may affect the suspension device 42, are not transmitted from the suspension device 42 to the vibration sensor 8.

[0076] As illustrated in FIG. 2, the vibration sensor 8 may be located at or in the inboard bearing 18. However, in other exemplary embodiments it is conceivable to provide the vibration sensor 8, or an additional vibration sensor, at or in the outboard bearing 20.

[0077] As illustrated in FIG. 2, the vibration sensor 8 may be located at an inboard side of the inboard bearing 18. However, in other exemplary embodiments it is conceivable to provide the vibration sensor 8, or an additional vibration sensor, at an outboard side of the inboard bearing 18.

[0078] As illustrated in FIG. 2, the vibration sensor 8 may be located at the inner race-forming part 22′ of the inboard bearing 18. However, in other exemplary embodiments it is conceivable to provide the vibration sensor 8, or an additional vibration sensor, at the outer race-forming part 24′ of the inboard bearing 18.

[0079] FIG. 2 further illustrates that the vibration sensor 8 may be located between the inboard bearing 18 (such as at its inner race-forming part 22′) and the central wheel support member 14. The central wheel support member may form part of the wheel suspension control system 100 in at least some exemplary embodiments.

[0080] As mentioned previously, the suspension device 42 may comprises an air suspension, such as including a bellows, wherein the processing circuitry 40 is configured to adjust the air pressure in the suspension device (e.g. the air pressure in a bellows) based on the measurement signals received from the vibration sensor 8. In other exemplary embodiments, the suspension device 42 may comprise a shock absorber, wherein the shock absorber comprises a cylinder in which hydraulic fluid is housed and a piston movable inside the cylinder, wherein the piston is provided with at least one hole and/or valve defining an opening area allowing hydraulic fluid to pass through the piston, wherein the processing circuitry 40 is configured to adjust the damping coefficient of the shock absorber, such as by adjusting the opening area, based on the measurement signals received from the vibration sensor 8.

[0081] In at least some exemplary embodiments, the processing circuitry 40 may be configured to adjust the vehicle speed, by controlling (with a control signal) a propulsion unit 44 of the vehicle, based on the measurement signals received by from the vibration sensor 8. In some exemplary embodiments, the propulsion unit 44 may be comprised in the wheel suspension control system 100.

[0082] Thus, depending on the type of vibrations, size, frequency, etc. that are measured by the vibration sensor 8, the processing circuitry 40 may, control both the suspension device 42 (i.e. a suspension parameter thereof) and the propulsion unit 44. For instance the processing circuitry 40 may determine that the stiffness, damping and/or ride height should be increased or decreased while also increasing or decreasing the velocity of the vehicle. Suitably, such determinations may be based on a classification of the type of road on which the vehicle is currently travelling, wherein different pre-defined types of roads may activate different control settings stored in a memory of the processing circuitry 40.

[0083] FIG. 3 is a schematic illustration of a method 200 in accordance with at least one exemplary embodiment of the invention. The method 200 is a method of controlling a suspension device (such as suspension devices 6 and 42 illustrated in FIGS. 1 and 2) connected to a wheel axle carrying a road wheel. The method 200 comprises: [0084] in a step S1, providing at least one vibration sensor at or in a wheel end bearing connected to said road wheel, [0085] in a step S2, measuring, by means of the vibration sensor, vibrations propagated from the road wheel to the wheel end bearing when the road wheel travels on a road having surface variations, [0086] in a step S3, transmitting measurement signals representing the measured vibrations, [0087] in a step S4, receiving, by a processing circuitry, the transmitted measurement signals, and [0088] in a step S5, controlling, by the processing circuitry, at least one suspension parameter of the suspension device, such as stiffness, damping and/or ride height of the suspension device, based on the received measurement signals.

[0089] It should be noted that the steps S1-S5 do not always have to be performed as consecutive steps. Suitably, each one of steps S2-S5 may be performed simultaneously, as the vibration sensor may continuously measure the vibrations and the processing circuitry may continuously control the suspension parameters as it continuously receives measurement signals from the vibration sensor.

[0090] In at least some exemplary embodiments, the step S5 may comprise (for a suspension device comprising an air suspension, such as including a bellows), adjusting, by means of the processing circuitry, the air pressure in the suspension device based on the received measurement signals. In at least some exemplary embodiments the step S5 may comprise (for a suspension device comprising a shock absorber, wherein the shock absorber comprises a cylinder in which hydraulic fluid is housed and a piston movable inside the cylinder, wherein the piston is provided with at least one hole and/or valve defining an opening area allowing hydraulic fluid to pass through the piston), adjusting, by means of the processing circuitry, the damping coefficient of the shock absorber, such as by adjusting the flow opening area, based on the received measurement signals. In some exemplary embodiments, the step S5 may comprise adjusting both the air pressure of an air suspension and the damping coefficient of a shock absorber, and/or a ride height of the vehicle.

[0091] The method 200 may optionally comprise: [0092] in a step S6, adjusting, by means of the processing circuitry, the vehicle speed, by controlling a propulsion unit of the vehicle, based on the received measurement signals. It should be noted that step S6 may be performed at the same time as for instance step S5.

[0093] There may be provided a computer program comprising program code means for performing the steps S1-S6 when said program is run on a computer. Similarly, there may be provided a computer readable medium carrying a computer program comprising program code means for performing the steps S1-S6 when said program product is run on a computer. A processing circuitry (such as the processing circuitry 40 in FIG. 2) may be provided for controlling a suspension parameter of a suspension device (such as suspension device 6, 42 in FIG. 1 and FIG. 2), the processing circuitry being configured to perform the steps S1-S6.

[0094] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.