Method and apparatus for active dynamic trimming of suspension damping including negative stiffness

Patent metadata

Field	Value
Publication number	US-2016347144-A1
Application number	US-201514724045-A
Country	US
Kind code	A1
Filing date	May 28, 2015
Priority date	May 28, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

A suspension assembly between a sprung element and an unsprung element includes a load-carrying spring and a negative stiffness element between the sprung element and the unsprung element. The load-carrying spring element is configured with a positive spring rate to support a static load of the sprung element. The negative stiffness element is configured with a negative spring rate and is configured to exert a force opposing the spring rate of the spring, the negative spring rate has a magnitude that cancels the positive spring rate at a zero deflection point of the suspension assembly. The suspension assembly also includes an active trimming mechanism which is configured to move a plurality of pivot points of the negative stiffness element to achieve a trimmed position of the negative stiffness element.

First claim

1 . A suspension assembly between a sprung element and an unsprung element, comprising:
a load-carrying spring and a negative stiffness element between the sprung element and the unsprung element; the load-carrying spring element configured with a positive spring rate to support a static load of the sprung element; the negative stiffness element configured with a negative spring rate and configured to exert a force opposing the spring rate of the spring, said negative spring rate having a magnitude that cancels the positive spring rate at a zero deflection point of the suspension assembly; and an active trimming mechanism, including a control module, configured to move a plurality of pivot points of the negative stiffness element to achieve a trimmed position of the negative stiffness element.

2 . The suspension assembly of claim 1 , wherein said negative spring rate having a magnitude that cancels the positive spring rate at a zero deflection point of the suspension assembly comprises the negative spring rate having a magnitude that fully cancels the positive spring rate at a zero deflection point of the suspension assembly.

3 . The suspension assembly of claim 1 , wherein said negative spring rate having a magnitude that cancels the positive spring rate at a zero deflection point of the suspension assembly comprises the negative spring rate having a magnitude that partially cancels the positive spring rate at a zero deflection point of the suspension assembly.

4 . The suspension assembly of claim 1 , wherein the negative stiffness element comprises a tension spring and linkage assemblies configured to generate an separating force on the sprung element relative to the unsprung element.

5 . The suspension assembly of claim 1 , wherein the active trimming mechanism is configured to move the plurality of pivot points of the negative stiffness element to achieve a trimmed position of the negative stiffness element based on a change in at least one of the static load of the sprung element and a dynamic load of the sprung element.

6 . The suspension assembly of claim 1 , wherein the active trimming mechanism comprises at least one actuator configured to move the pivot points of the negative stiffness element to achieve a trimmed position of the negative stiffness element.

7 . The suspension assembly of claim 6 , wherein the at least one actuator comprises a hydraulic linear actuator.

8 . The suspension assembly of claim 6 , wherein the at least one actuator comprises an electric linear actuator.

9 . The suspension assembly of claim 6 , wherein the at least one actuator comprises a rotational actuator.

10 . The suspension assembly of claim 5 , wherein the active trimming mechanism comprises at least one sensor device configured to determine the static load of the sprung element and the dynamic load of the sprung element.

11 . A method for controlling a suspension assembly between a sprung element and an unsprung element, the suspension assembly including a negative stiffness element, an active trimming mechanism, and a control module, comprising:
monitoring at least one sensor device configured to measure system operating parameters; determining a desired trim state of the active trimming mechanism based on the measured system operating parameters; determining an actual trim state based on a measured actual trim deflection; comparing the desired trim state to the actual trim state; generating a signal input for the active trimming mechanism based on the comparison of the desired trim state to the actual trim state; and controlling the active trimming mechanism based upon the generated signal input to move a plurality of pivot points of the negative stiffness element to achieve a trimmed position of the negative stiffness element; and operating the negative stiffness element in a trimmed position.

12 . The method of claim 11 , wherein monitoring at least one sensor device configured to measure system operating parameters comprises monitoring a brake pedal sensor, a gas pedal sensor, a steering angle sensor and an acceleration sensor.

13 . The method of claim 11 , wherein determining a desired trim state of the active trimming mechanism based on the measured system operating parameters comprises using a model configured to estimate a suspension deflection based on the measured system operating parameters.

14 . The method of claim 11 , wherein determining a desired trim state of the active trimming mechanism based on the measured system operating parameters comprises using a look up table configured to estimate a suspension deflection based on the measured system operating parameters.

15 . The method of claim 11 further comprising:
determining a desired suspension state based on the measured system operating parameters;
monitoring an actual suspension deflection;
determine an actual suspension state based on the monitored actual suspension deflection;
generating an optimal feedback command signal for the active trimming mechanism based on the determined desired suspension state and the determined actual suspension state; and
controlling the active trimming mechanism based upon the generated signal input and the optimal feedback command to move a plurality of pivot points of the negative stiffness element to achieve the trimmed position of the negative stiffness element.

16 . The method of claim 15 , wherein generating an optimal feedback command signal for the active trimming mechanism based on the determined desired suspension state and the determined actual suspension state comprises using linear-quadratic-Gaussian (LQG) control methods.

17 . An apparatus for controlling a suspension assembly between a sprung element and an unsprung element comprising:
a load-carrying spring and a negative stiffness element between the sprung element and the unsprung element; the load-carrying spring configured with a positive spring rate to support a static load of the sprung element; the negative stiffness element configured with a negative spring rate and configured to exert a force opposing the spring rate of the spring, said negative spring rate having a magnitude that cancels the positive spring rate at a zero deflection point of the suspension assembly; an active trimming mechanism configured move a plurality of pivot points of the negative stiffness element to achieve a trimmed position of the negative stiffness element; at least one sensor device configured to measure system operating parameters and provided to an active trimming mechanism control module; and the active trimming mechanism control module configured to execute a routine comprising the following steps:
monitor the at least one sensor device configured to measure system operating parameters;
determine a desired trim state of the active trimming mechanism based on the monitored sensor measurements;
determine an actual trim state based on a measured actual trim deflection;
compare the desired trim state to the actual trim state;
generate a signal input for the active trimming mechanism based on the comparison of the desired trim state to the actual trim state; and
control the active trimming mechanism based upon the generated signal input to move a plurality of pivot points of the negative stiffness element to achieve a trimmed position of the negative stiffness element.

18 . The apparatus of claim 17 , wherein the routine executed by the active trimming mechanism control module further comprises the following steps:
determine a desired suspension state based

Assignees

• Gm Global Tech Operations Llc

Inventors

• Suissa Avshalom

Classifications

• B60G2204/62

  Adjustable continuously, e.g. during driving · CPC title

• B60G2202/30

  Spring/Damper and/or actuator Units · CPC title

• B60G17/00

  Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load {(levelling or stabilising systems for tippers B60P1/045)} · CPC title

• B60G2200/142

  with a single lateral arm, e.g. MacPherson type · CPC title

• B60G2800/91

  Suspension Control · CPC title