# US 10,371,228 B2 · Control strategy for a variable spring rate absorber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,228 B2 - Document ID: US10371228B2 - Status: Granted - Kind: B2 - Application number: 15/512,858 - Filed: 2015-09-10 - Published: 2017-08-31 - Granted: 2019-08-06 - Earliest claimed: 2014-09-23 - Assignees: BorgWarner Inc. - Applicants: BorgWarner Inc. - Inventors: Mark Buchanan; Robert Francis Keller; Xiaobing Liu - Web page: https://patentgrep.com/patent/US10371228B2 ## CPC - F16F 15/002: {characterised by the control method or circuitry (control of mechanical oscillations per se G05D19/00)} - F02D 41/0097: {using means for generating speed signals} - F16F 2228/001: Specific functional characteristics in numerical form or in the form of equations - F16F 2230/18: Control arrangements - F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) ## Abstract A variable spring rate absorber is adjusted to provide the vibration attenuation characteristics needed to match current operating conditions. Control of a variable spring rate absorber determines the desired absorber spring rate for existing conditions based on a number of inputs and predetermined characterization tables. Once the spring rate is calculated, a predetermined map may be used to determine the absorber setting needed to achieve the desired spring rate. A sensor may be used to measure the actual state of the absorber to determine the extent to which the setting must be adjusted to achieve the desired spring rate. ## Claims ### Claim 1 A method of controlling a variable absorber which has an actuator with a sensor, including reading input signals, determining a desired spring rate for the variable absorber, determining a control setting for the actuator that achieves a commanded spring rate, reading the sensor to acquire an actual setting of the actuator, calculating a control error signal equal to the difference between the control setting and the actual setting, and using the control error signal sending a control signal to the actuator, thereby adjusting the actuator to the control setting. ### Claim 2 (depends on 1) A method according to claim 1 wherein the commanded spring rate is equal to the desired spring rate. ### Claim 3 (depends on 1) A method according to claim 1 wherein the desired spring rate is corrected by determining a correction term that is applied to the desired spring rate to produce the commanded spring rate. ### Claim 4 (depends on 3) A method according to claim 3 wherein the correction term is determined by combining a target amplitude and a target phase angle with a calculated amplitude and a calculated phase angle. ### Claim 5 (depends on 3) A method according to claim 3 wherein the correction term is determined from a spectral analysis of the input signals. ### Claim 6 (depends on 3) A method according to claim 3 wherein the correction term is determined using a fast fourier transform analysis. ### Claim 7 (depends on 3) A method according to claim 3 wherein the correction term is determined using a least squares method. ### Claim 8 (depends on 1) A method according to claim 1 wherein the desired spring rate is determined from a spring rate map based on the input signals. ### Claim 9 (depends on 1) A method according to claim 1 wherein the control setting for the actuator is determined from an actuator setting map based on the desired spring rate. ### Claim 10 (depends on 1) A method according to claim 1 wherein a predicted spring rate is determined and the commanded spring rate is determined by combining the predicted spring rate with the desired spring rate. ### Claim 11 (depends on 3) A method according to claim 3 wherein a predicted spring rate is determined and the commanded spring rate is determined by combining the predicted spring rate with the desired spring rate and the correction term. ### Claim 12 A method for adjusting an absorber wherein the absorber has an actuator with a setting sensor and wherein the absorber is assembled in a product with condition sensors, including reading input signals from the condition sensors, determining a desired spring rate for the absorber based on the input signals, determining a control setting for the actuator that achieves the desired spring rate, reading the setting sensor to acquire an actual setting of the actuator, calculating a control error signal equal to the difference between the control setting and the actual setting, and using the control error signal sending a proportional control signal to the actuator, thereby adjusting the actuator to the control setting. ### Claim 13 A method for controlling a variable absorber in a vehicle wherein the vehicle includes an engine and produces an engine speed signal and a vehicle speed signal, the variable absorber having an actuator that produces an actual setting signal including reading the engine speed signal, determining a desired spring rate for the absorber from the engine speed signal, determining a commanded spring rate from the desired spring rate, determining a desired actuator setting to achieve the commanded spring rate, reading the actual setting signal, calculating a control error signal from the actuator setting and the actual setting signal, and applying the control error signal adjusting the actuator to the desired actuator setting. ### Claim 14 (depends on 13) A method according to claim 13 wherein the commanded spring rate is equal to the desired spring rate. ### Claim 15 (depends on 13) A method according to claim 13 wherein the desired spring rate is corrected by determining a correction term that is applied to the desired spring rate to produce the commanded spring rate. ### Claim 16 (depends on 15) A method according to claim 15 wherein the correction term is determined by combining a target amplitude with a calculated amplitude and combining a target phase angle with a calculated phase angle. ### Claim 17 (depends on 15) A method according to claim 15 wherein the correction term is determined from a spectral analysis of the engine speed signal and the vehicle speed signal. ### Claim 18 (depends on 15) A method according to claim 15 wherein the correction term is determined using a fast fourier transform analysis of the engine speed signal and the vehicle speed signal. ### Claim 19 (depends on 15) A method according to claim 15 wherein the correction term is determined using a least squares method analysis of the engine speed signal and the vehicle speed signal. ### Claim 20 (depends on 13) A method according to claim 13 wherein the desired spring rate is determined from a spring rate map based on the engine speed signal signals. ### Claim 21 (depends on 13) A method according to claim 13 wherein the control setting for the actuator is determined from an actuator setting map based on the desired spring rate. ### Claim 22 (depends on 13) A method according to claim 13 wherein a predicted spring rate is determined and the commanded spring rate is determined by combining the predicted spring rate with the desired spring rate. ### Claim 23 (depends on 13) A method according to claim 13 wherein a predicted spring rate is determined and the commanded spring rate is determined by combining the predicted spring rate with the desired spring rate and the correction term.