Active suspension system for a work vehicle having adjustable performance parameters

• US 6,000,703 A
• Filed: 11/12/1997
• Issued: 12/14/1999
• Est. Priority Date: 11/12/1997
• Status: Expired due to Term

• Current Assignee: Blue Leaf IP Incorporated (CNH Industrial N.V.), CNH America Llc (CNH Industrial N.V.)
• Original Assignee: Case Corporation (CNH Industrial N.V.)
• Inventors: Schmitz, Geoffrey W., Schubert, William L.
• Primary Examiner(s): Mai, Lanna
• Assistant Examiner(s): CUFF, MICHAEL A
• Application Number:
  US08/968,351
• Time in Patent Office: 762 Days
• Field of Search: 280/5.5, 280/5.503, 280/5.517, 280/5.518, 280/6.154, 280/6.155, 280/124.157, 180/89.12
• US Class Current: 280/5.518
• CPC Class Codes: B60G 17/0165 to an external condition, e.g. rough road surface, side wind
• CPC Class Codes: B60G 2300/082 Tractors
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/821 Uneven, rough road sensing affecting vehicle body vibration
• CPC Class Codes: B60G 2401/14 Photo or light sensitive means, e.g. Infrared
• CPC Class Codes: B60G 2401/16 GPS track data
• CPC Class Codes: B60G 2401/174 Radar
• CPC Class Codes: B60G 2600/182 Active control means
• CPC Class Codes: B60G 2600/20 Manual control or setting means
• CPC Class Codes: B60G 2600/70 Computer memory; Data storage, e.g. maps for adaptive control
• CPC Class Codes: B60G 2800/162 Reducing road induced vibrations

Abstract

An active suspension system for a work vehicle includes an active vibration isolator mounted between the chassis and the cab which controls movement of the cab relative to the chassis in response to a control signal depending on a detected condition (e.g., bumpiness) of a surface ahead of the vehicle. The method of controlling the system includes detecting the bumpiness of the surface on which the vehicle travels, adjusting a performance parameter in response to the detected bumpiness, generating the control signal in response to the detected bumpiness, and applying the control signal to the isolator. Apparatus for such an active suspension system is also disclosed. Bumpiness can be estimated or monitored using vehicle speed, past performance, geo-referenced maps and forward-looking sensors. The adjustable performance parameters include gain and frequency response. The system allows an operator to manually adjust the gain and, thus, the frequency response.

Claims

1. In an off-road work vehicle including a chassis, a propulsion system coupled to the chassis to propel the work vehicle along a surface in a forward direction, an operator'"'"'s cab supported by the chassis, and an active suspension system including at least one active vibration isolator coupled between the chassis and the cab, each active vibration isolator including a hydraulic actuator disposed to move the cab relative to the chassis based upon fluid selectively applied to the actuator by a valve assembly in response to a control signal, a method of controlling the active suspension system comprising the steps of:

sensing movement of the cab due to disturbances in the chassis and generating a first parameter indicative of the sensed movement;

detecting a condition of the surface ahead of the work vehicle in the forward direction and generating a second parameter indicative of the condition;

providing the first and second parameters as inputs to a processing circuit configured to execute a predetermined control program having at least one adjustable performance parameter which depends upon the second parameter, the at least one adjustable performance parameter being selected from the group consisting of gain of the suspension system and frequency response of the suspension system;

generating the control signal for the valve assembly to attenuate transmission of force between the cab and the chassis by executing the control program, the control signal depending upon both the first and second parameters; and

applying the control signal to the valve assembly, whereby performance of the suspension system depends on the detected condition of the surface.

2. The method of claim 1 wherein the control signal depends primarily upon the sensed movement of the cab and secondarily upon the detected condition of the surface.

3. The method of claim 1 wherein the detected condition of the surface is the bumpiness of the surface.

11. The method of claim 3 wherein the detecting step includes sensing the bumpiness of the surface ahead of the work vehicle using a forward-looking sensor.

12. The method of claim 3 wherein the adjusted performance parameter is system gain.

4. In a work vehicle including a chassis, a propulsion system coupled to the chassis to propel the work vehicle along a surface in a forward direction, an operator'"'"'s cab supported by the chassis, and an active suspension system including at least one active vibration isolator coupled between the chassis and the cab to control movement of the cab relative to the chassis in response to a control signal, a method of controlling the active suspension system comprising the steps of:

detecting a condition of the surface ahead of the work vehicle in the forward direction, the detected condition of the surface being the bumpiness of the surface, by determining the ground velocity of the work vehicle and estimating the bumpiness of the surface based upon the ground velocity;

adjusting at least one performance parameter of the active suspension system in response to the detected condition of the surface the at least one adjustable performance parameter being selected from the group consisting of gain of the active suspension system and frequency response of the active suspension system;

generating the control signal to attenuate transmission of force between the cab and the chassis, the control signal depending at least upon the adjusted performance parameter of the suspension system; and

applying the control signal to the suspension system, whereby performance of the suspension system depends on the detected condition of the surface.

5. The method of claim 4 wherein the bumpiness of the surface is estimated to equal a first value when the ground velocity is below a predetermined threshold speed, and is estimated to equal a second value when the ground velocity is above the predetermined threshold speed.

6. In a work vehicle including a chassis, a propulsion system coupled to the chassis to propel the work vehicle along a surface in a forward direction, an operator'"'"'s cab supported by the chassis, and an active suspension system including at least one active vibration isolator coupled between the chassis and the cab to control movement of the cab relative to the chassis in response to a control signal, a method of controlling the active suspension system comprising the steps of:

detecting a condition of the surface ahead of the work vehicle in the forward direction, the detected condition of the surface being the bumpiness of the surface, by evaluating previous sensed movements of the cab and estimating the bumpiness of the surface based upon the previous sensed movements;

adjusting at least one performance parameter of the active suspension system in response to the detected condition of the surface, the at least one adjustable performance parameter being selected from the group consisting of gain of the active suspension system and frequency response of the active suspension system;

generating the control signal to attenuate transmission of force between the cab and the chassis, the control signal depending at least upon the adjusted performance parameter of the suspension system; and

applying the control signal to the suspension system, whereby performance of the suspension system depends on the detected condition of the surface.

7. In a work vehicle including a chassis, a propulsion system coupled to the chassis to propel the work vehicle along a surface in a forward direction, an operator'"'"'s cab supported by the chassis, and an active suspension system including at least one active vibration isolator coupled between the chassis and the cab to control movement of the cab relative to the chassis in response to a control signal, a method of controlling the active suspension system comprising the steps of:

detecting a condition of the surface ahead of the work vehicle in the forward direction by generating location signals representative of the position of the work vehicle on the surface and determining the condition of the surface using a geo-referenced map including spatially-variable data indicative of the condition and the location signals;

adjusting at least one performance parameter of the active suspension system in response to the detected condition of the surface, the at least one adjustable performance parameter being selected from the group consisting of gain of the active suspension system and frequency response of the active suspension system;

generating the control signal to attenuate transmission of force between the cab and the chassis, the control signal depending at least upon the adjusted performance parameter of the suspension system; and

applying the control signal to the suspension system, whereby performance of the suspension system depends on the detected condition of the surface.

8. The method of claim 7 wherein the detected condition of the surface is the bumpiness of the surface.

9. The method of claim 8 wherein the spatially-variable data indicates where the surface is a road and where the surface is a field.

10. The method of claim 8 wherein the spatially-variable data indicates movements of the cab which were sensed and recorded in a previous pass along the surface.

13. In an off-road work vehicle including a chassis, a propulsion system coupled to the chassis to propel the work vehicle along a surface in a forward direction, an operator'"'"'s cab supported by the chassis, and an active suspension system including at least one active vibration isolator coupled between the chassis and the cab, each active vibration isolator including a hydraulic actuator disposed to move the cab relative to the chassis based upon fluid selectively applied to the actuator by a valve assembly in response to a control signal, a method of controlling the active suspension system comprising the steps of:

sensing movement of the cab due to disturbances in the chassis and generating a first parameter indicative of the sensed movement;

detecting a condition of the surface ahead of the work vehicle in the forward direction and generating a second parameter indicative of the condition;

providing the first and second parameters as inputs to a processing circuit configured to execute a predetermined control program having at least one adjustable performance parameter which depends upon the second parameter;

generating the control signal for the valve assembly to attenuate transmission of force between the cab and the chassis by executing the control program, the control signal depending upon both the first and second parameters;

applying the control signal to the valve assembly, whereby performance of the suspension system depends on the detected condition of the surface; and

sensing displacement between the cab and the chassis using a displacement sensor, wherein the control signal further depends upon the sensed displacement to cause the cab to move to a steady-state position, and the performance parameter is the gain at which the sensed displacement causes the cab to move toward the steady-state position.

14. In an off-road work vehicle including a chassis, a propulsion system coupled to the chassis to propel the work vehicle along a surface in a forward direction, an operator'"'"'s cab supported by the chassis, and a suspension system including at least one active vibration isolator coupled between the chassis and the cab, each active vibration isolator including a hydraulic actuator disposed to move the cab relative to the chassis based upon fluid selectively applied to the actuator by a valve assembly in response to a control signal, an apparatus for controlling the active suspension system comprising:

means for sensing movement of the cab due to disturbances in the chassis and generating a first parameter indicative of the sensed movement;

means for detecting a condition of the surface ahead of the work vehicle in the forward direction and for generating a second parameter indicative of the condition;

means for providing the first and second parameters as inputs to a processing circuit configured to execute a predetermined control program having an adjustable performance parameter which depends upon the second parameter, the adjustable performance parameter being selected from the group consisting of gain of the suspension system and frequency response of the suspension system;

means for generating the control signal for the valve assembly to attenuate transmission of force between the cab and the chassis by executing the control program, the control signal depending upon both the first and second parameters; and

means for applying the control signal to the valve assembly, whereby performance of the suspension system depends on the detected condition of the surface.

15. The apparatus of claim 14 wherein the control signal depends primarily upon the sensed movement of the cab and secondarily upon the detected condition of the surface.

16. The apparatus of claim 14 wherein the detected condition of the surface is the bumpiness of the surface.

19. The apparatus of claim 16 wherein the detecting means includes means for sensing the bumpiness of the surface ahead of the work vehicle using a forward-looking sensor.

20. The apparatus of claim 14 wherein the adjustable performance parameter includes gain of the active suspension system.

17. In a work vehicle including a chassis, a propulsion system coupled to the chassis to propel the work vehicle along a surface in a forward direction, an operator'"'"'s cab supported by the chassis, and a suspension system including at least one active vibration isolator coupled between the chassis in response cab and configured to control movement of the cab relative to the chassis in response to a control signal, an apparatus for controlling the active suspension system comprising:

means for detecting a condition of the surface ahead of the work vehicle in the forward direction, the detected condition of the surface being the bumpiness of the surface, the detecting means including means for sensing ground velocity of the work vehicle and means for estimating the bumpiness of the surface based upon the ground velocity;

means for adjusting at least one performance parameter of the active suspension system in response to the detected condition of the surface, the at least one adjustable performance parameter being selected from the group consisting of gain of the suspension system and frequency response of the suspension system;

means for generating the control signal to attenuate transmission of force between the cab and the chassis, the control signal depending at least upon the adjusted performance parameter; and

means for applying the control signal to the suspension system, whereby performance of the suspension system depends on the detected condition of the surface.

18. In a work vehicle including a chassis, a propulsion system coupled to the chassis to propel the work vehicle along a surface in a forward direction, an operator'"'"'s cab supported by the chassis, and a suspension system including at least one active vibration isolator coupled between the chassis and the cab and configured to control movement of the cab relative to the chassis in response to a control signal, an apparatus for controlling the active suspension system comprising:

means for detecting a condition of the surface ahead of the work vehicle in the forward direction, the detecting means including means for generating location signals representing the position of the work vehicle and means for determining a condition of the surface vehicle using a geo-referenced map including spatially-variable data indictive of the condition and the location signals;

means for adjusting at least one performance parameter of the active suspension system in response to the detected condition of the surface, the at least one adjustable performance parameter being selected from the group consisting of gain of the suspension system and frequency response of the suspension system;

means for generating the control signal to attenuate transmission of force between the cab and the chassis, the control signal depending at least upon the adjusted performance parameter; and

means for applying the control signal to the suspension system, whereby performance of the suspension system depends on the detected condition of the surface.

21. In a work vehicle including a chassis, a propulsion system coupled to the chassis to propel the work vehicle along a surface in a forward direction, an operator'"'"'s cab supported by the chassis, and an active suspension system including at least one active vibration isolator coupled between the chassis and the cab to control movement of the cab relative to the chassis in response to a control signal, a method of controlling the active suspension system comprising the steps of:

actuating an operator-actuatable input device configured to generate an input signal;

adjusting the frequency response of the active suspension system in response to the input signal;

generating the control signal to attenuate transmission of force between the cab and the chassis, the control signal depending at least upon the adjusted frequency response of the suspension system; and

applying the control signal to the suspension system, whereby the frequency response of the suspension system depends on the actuation of the input device.