Arrangement for control of a chassis vibration damping device

• US 5,721,681 A
• Filed: 04/28/1995
• Issued: 02/24/1998
• Est. Priority Date: 05/02/1994
• Status: Expired due to Fees

• Current Assignee: Fichtel & Sachs AG
• Original Assignee: Fichtel & Sachs AG
• Inventors: Kutsche, Thomas, Borschert, Udo
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): PHAN, THAI Q
• Application Number:
  US08/430,566
• Time in Patent Office: 1,033 Days
• Field of Search: 280/707, 280/702, 280/703, 280/688, 364/424.046, 364/424.047, 364/426.037
• US Class Current: 701/37
• CPC Class Codes: B60G 17/018 characterised by the use of a specific signal treatment or control method
• CPC Class Codes: B60G 17/01908 Acceleration or inclination sensors characterised by the use of gyroscopes B60G21/08
• CPC Class Codes: B60G 2400/102 vertical
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/106 longitudinal with regard to vehicle, e.g. braking
• CPC Class Codes: B60G 2400/206 Body oscillation speed; Body vibration frequency
• CPC Class Codes: B60G 2400/60 Load
• CPC Class Codes: B60G 2400/63 Location of the center of gravity
• CPC Class Codes: B60G 2400/91 Frequency
• CPC Class Codes: B60G 2401/904 the sensor being an xyz axis sensor
• CPC Class Codes: B60G 2500/10 Damping action or damper
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2600/60 Signal noise suppression; Electronic filtering means
• CPC Class Codes: B60G 2600/70 Computer memory; Data storage, e.g. maps for adaptive control

Abstract

For control of a frame-vibration damping device with a variable damping force characteristic in a motor vehicle (1), adjustment devices (9) of the vibration dampers (7) being controlled as a function of evaluated measurement signals of a single acceleration sensor (17) detecting the instantaneous value of an acceleration variable. The measurement direction (19) of the acceleration sensor (17) is turned at an angle of 45° in each case to the three axes of motion of the vehicle (longitudinal axis x, transverse axis y, and vertical axis z). Signal separation means (25) separate a first measurement signal component (b_z) by means of a bandpass filter (31) with midfrequency tuned to the natural frequency of the vehicle body (3), which represents the acceleration component in the vertical direction (z). Subtraction means (33), which develop the difference of the measurement signal of the acceleration sensor (17) and the first measurement signal component (b_z), deliver a second measurement signal component (b_xy) for the acceleration component in the plane of the longitudinal axis x and the transverse axis y. Evaluation means (35, 37) associated with the two measurement signal components deliver damping force requirement components n_Z and n_xy which are added by adding means (39) to obtain a control signal which controls the adjusting device (9) representing the entire damping force requirement.

Claims

1. A vehicle for travelling along a travel surface, said vehicle including an adjustable vibration damping system for damping vibrations transmitted to said vehicle by said travel surface, said vehicle comprising:

a vehicle body;

said vehicle body having a longitudinal axis in a direction of normal longitudinal travel of said vehicle, said longitudinal axis being parallel to said travel surface;

said vehicle body having a lateral axis, said lateral axis being orthogonal to said longitudinal axis, and said lateral axis being parallel to said travel surface;

said lateral axis and said longitudinal axis forming a substantially horizontal plane;

said vehicle body having a vertical axis, said vertical axis being orthogonal to said longitudinal axis, to said lateral axis, and to said travel surface;

said vehicle body having a natural frequency of vibration in a direction along said vertical axis;

said vehicle additionally comprising at least one wheel for contacting said travel surface;

said adjustable vibration damping system comprising;

adjustable vibration damping means for applying an adjusted vibrational damping action between said vehicle body and said at least one wheel in response to at least one vibrational damping control signal;

a sole translational acceleration sensor positioned at a sole point on said vehicle body for generating a singular acceleration signal;

said sole translational acceleration sensor having a sole measurement axis;

said sole translational acceleration sensor being disposed to sense an acceleration of said vehicle body along said sole measurement axis;

said sole measurement axis of said sole translational acceleration sensor being disposed at a vertical angle with respect to said vertical axis;

said vertical angle comprising a substantial angle;

said sole measurement axis of said sole translational acceleration sensor being disposed at a horizontal angle with respect to said horizontal plane;

said horizontal angle comprising a substantial angle;

processing means for processing said singular acceleration signal to generate therefrom said vibrational damping control signal, said processing means comprising;

separating means for separating said singular acceleration signal into;

a first acceleration component, said first acceleration component being the component of said singular acceleration signal in the direction of said vertical axis of said vehicle body; and

a second acceleration component, said second acceleration component being the component of said singular acceleration signal in directions substantially orthogonal to said vertical axis of said vehicle body;

first evaluation means for evaluating said first acceleration component and for determining a first damping force component in said direction of said vertical axis of said vehicle body;

second evaluation means for evaluating said second acceleration component and for determining a second damping force component in said directions substantially orthogonal to said vertical axis of said vehicle body;

combining means for combining said first damping force component and said second damping force component to form said at least one vibrational damping control signal; and

means connecting said combining means and said adjustable vibration damping means to apply the adjusted vibrational damping action between said vehicle body and said at least one wheel in response to said at least one vibrational damping signal.

2. A vehicle according to claim 1, wherein said separating means comprises:

a bandpass filter having a midfrequency tuned to said natural frequency of vibration of said vehicle body along said vertical axis; and

subtraction means for subtracting said first acceleration component from said singular acceleration signal generated by said sole translational acceleration sensor to thereby form said second acceleration component.

3. A vehicle according to claim 2, wherein:

said first evaluation means comprises a memory of characteristics associating a plurality of values of said first acceleration component with associated values of said first damping force component.

4. A vehicle according to claim 3, wherein:

said second evaluation means comprises a memory of characteristics associating a plurality of values of said second acceleration component with associated values of said second damping force component.

5. A vehicle according to claim 4, wherein:

said sole measurement axis of said sole translational acceleration sensor is disposed at a substantial longitudinal angle with respect to said longitudinal axis of said vehicle body; and

said sole measurement axis of said sole translational acceleration sensor is disposed at a substantial lateral angle with respect to said lateral axis of said vehicle body.

6. A vehicle according to claim 5, wherein:

said longitudinal angle is at least one of;

substantially less than and substantially equal to said lateral angle.

7. A vehicle according to claim 6, wherein:

said sole measurement axis of said sole translational acceleration sensor is disposed with respect to said longitudinal axis of said vehicle body and said lateral axis of said vehicle body such that said second acceleration component comprises substantially equal portions of accelerations along said longitudinal axis and said lateral axis of said vehicle body.

8. A vehicle according to claim 7, wherein each of said longitudinal angle, said lateral angle and said vertical angle are substantially equal to about 45 degrees.

9. A vehicle according to claim 8, wherein:

said processing means additionally comprises lowpass filter means;

said lowpass filter means being substantially permeable to said natural frequency of vibration of said vehicle body along said vertical axis;

said at least one wheel having a natural frequency; and

said lowpass filter being substantially nonpermeable to said natural frequency of said at least one wheel.

10. A vehicle according to claim 9, wherein:

said processing means additionally comprises hysteresis means for temporarily delaying a change in the damping force characteristic.

11. A vehicle according to claim 10, wherein:

said hysteresis means comprises means for temporarily delaying a change from a harder damping force characteristic to a softer damping force characteristic;

said adjustable vibration damping means comprises proportional valve means;

said proportional valve means having a variable cross sectional area; and

said processing means comprises means for varying said cross sectional area of said proportional valve means in accordance with a magnitude of said vibrational damping control signal.

12. A suspension system in a motor vehicle including a suspension system having an adjustable damping system with an acceleration sensor, said vehicle being for travel over a travel surface, said vehicle comprising:

a vehicle body;

said vehicle body having a longitudinal axis in a direction of normal longitudinal travel of said vehicle, said longitudinal axis being parallel to said travel surface;

said vehicle body having a lateral axis, said lateral axis being orthogonal to said longitudinal axis, and said lateral axis being parallel to said travel surface;

said lateral axis and said longitudinal axis forming a substantially horizontal plane; and

said vehicle body having a vertical axis disposed substantially orthogonally with respect to said horizontal plane and said travel surface; and

at least one vehicle wheel;

said suspension system comprising;

adjustable vibration damping means for applying a vibrational damping action between said vehicle body and said at least one vehicle wheel and for varying at least one characteristic of said applied vibrational damping action in response to at least one vibrational damping control signal;

means for sensing an acceleration representative of said vehicle body and for generating a singular acceleration signal representative thereof, said sensing means consisting of a sole uniaxial acceleration sensor having a sole measurement axis, said sole uniaxial acceleration sensor having means for being mounted at a sole point on the body of a vehicle;

said sole measurement axis of said sole uniaxial acceleration sensor being disposed at a substantial vertical angle with respect to said vertical axis of said vehicle body;

said sole measurement axis of said sole uniaxial acceleration sensor being disposed at a substantial horizontal angle with respect to said horizontal plane;

means for processing said singular acceleration signal representative of said vehicle body acceleration and for generating therefrom said at least one vibrational damping control signal;

said processing means comprising;

means for separating said singular acceleration signal representative of said vehicle body acceleration into at least two separate components;

means for separately evaluating each of said at least two separate components and separately producing at least two subsidiary control signals respectively representative of each of said at least two separate components; and

means for generating said at least one vibrational damping control signal as a function of at least one of said at least two subsidiary control signals; and

means connecting said generating means and said adjustable vibration damping means for applying a vibrational damping action between said vehicle body and said at least one vehicle wheel and for varying at least one characteristic of said applied vibrational damping action in response to said at least one vibrational damping control signal.

13. The suspension system according to claim 12, wherein:

said separating means comprises a bandpass filter having a midfrequency tuned to said natural frequency of vibration of said vehicle body along said vertical axis;

said at least two separate components comprise a first acceleration component and a second acceleration component;

said first acceleration component being the component of said singular acceleration signal in the direction of said vertical axis of said vehicle body;

said second acceleration component being the component of said singular acceleration signal in the directions substantially orthogonal to said vertical axis of said vehicle body; and

said separating means comprises subtraction means for subtracting said first acceleration component from said singular acceleration signal generated by said sole uniaxial acceleration sensor to thereby form said second acceleration component.

14. The suspension system according to claim 13, wherein said means for separately evaluating each of said at least two separate components and separately producing at least two subsidiary control signals respectively representative of each of said at least two separate components comprises:

first evaluation means for evaluating said first acceleration component and for determining a first one of said at least two separate subsidiary control signals;

second evaluation means for evaluating said second acceleration component and for determining a second one of said at least two subsidiary control signals;

said first subsidiary control signal representing a first damping force component;

said second subsidiary control signal representing a second damping force component; and

said first evaluation means comprises a memory of characteristics associating a plurality of values of said first acceleration component with associated values of said first damping force.

15. The suspension system according to claim 14, wherein:

said second evaluation means comprises a memory of characteristics associating a plurality of values of said second acceleration component with associated values of said second damping force component.

16. The suspension system according to claim 15, wherein:

said sole measurement axis of said sole translational acceleration sensor is disposed at a substantial longitudinal angle with respect to said longitudinal axis of said vehicle body; and

said sole measurement axis of said sole translational acceleration sensor is disposed at a substantial lateral angle with respect to said lateral axis of said vehicle body.

17. The suspension system according to claim 16, wherein said longitudinal angle is at least one of:

substantially less than and substantially equal to said lateral angle.

18. The suspension system according to claim 17, wherein:

said sole measurement axis of said sole translational acceleration sensor is disposed with respect to said longitudinal axis of said vehicle body and said lateral axis of said vehicle body such that said second acceleration component comprises substantially equal portions of accelerations along said longitudinal axis and said lateral axis of said vehicle body;

each of said longitudinal angle, said lateral angle and said vertical angle are substantially equal to about 45 degrees;

said processing means additionally comprises lowpass filter means;

said lowpass filter means being substantially permeable to said natural frequency of vibration of said vehicle body along said vertical axis;

said at least one wheel having a natural frequency;

said lowpass filter being substantially nonpermeable to said natural frequency of said at least one wheel;

said processing means additionally comprises hysteresis means for temporarily delaying a change in the damping force characteristic;

said hysteresis means comprises means for temporarily delaying a change from a harder damping force characteristic to a softer damping force characteristic;

said adjustable vibration damping means comprises proportional valve means;

said proportional valve means having a variable cross sectional area; and

said processing means comprises means for varying said cross sectional area of said proportional valve means in accordance with a magnitude of said vibrational damping control signal.

19. A suspension system in a motor vehicle including a suspension system having an adjustable damping system with an acceleration sensor, said vehicle being for travel over a travel surface, said vehicle comprising:

a vehicle body;

said vehicle body having a longitudinal axis in a direction of normal longitudinal travel of said vehicle, said longitudinal axis being parallel to said travel surface;

said vehicle body having a lateral axis, said lateral axis being orthogonal to said longitudinal axis, and said lateral axis being parallel to said travel surface;

said lateral axis and said longitudinal axis forming a substantially horizontal plane; and

said vehicle body having a vertical axis disposed substantially orthogonally with respect to said horizontal plane and said travel surface; and

at least one vehicle wheel;

said suspension system comprising;

adjustable vibration damping means for applying a vibrational damping action between said vehicle body and said at least one vehicle wheel and for varying at least one characteristic of said applied vibrational damping action in response to at least one vibrational damping control signal;

means for sensing an acceleration representative of said vehicle body and for generating a singular acceleration signal representative thereof, said sensing means consisting of a sole uniaxial acceleration sensor having a sole measurement axis, said sole uniaxial acceleration sensor having means for being mounted at a sole point on the body of a vehicle;

said sole measurement axis of said sole uniaxial acceleration sensor being disposed at a substantial angle with respect to said vertical axis of said vehicle body;

said sole measurement axis of said sole uniaxial acceleration sensor being disposed at a substantial angle with respect to said horizontal plane;

means for processing said singular acceleration signal and for generating therefrom said at least one vibrational damping control signal; and

said processing means comprising means for separating said singular acceleration signal into at least two separate acceleration components.

20. The suspension system according to claim 19, wherein:

said at least two separate acceleration components comprise a first acceleration component and a second acceleration component;

said first acceleration component being the component of said singular acceleration signal in the direction of said vertical axis of said vehicle body;

said second acceleration component being the component of said singular acceleration signal in the directions substantially orthogonal to said vertical axis of said vehicle body; and

said separating means comprises subtraction means for subtracting said first acceleration component from said singular acceleration signal generated by said sole uniaxial acceleration sensor to thereby form said second acceleration component.