Adaptive control of a linear actuator

Patent metadata

Field	Value
Publication number	US-9316271-B2
Application number	US-201414338997-A
Country	US
Kind code	B2
Filing date	Jul 23, 2014
Priority date	Mar 17, 2014
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A vehicle or other system includes hydraulic fluid, an actuatable device such as a clutch that includes a linear actuator, e.g., a clutch piston. The linear actuator is moveable via a pressure from the fluid to actuate the actuatable device. A position sensor measures and outputs a position of the linear actuator as a position signal. A controller is programmed to generate increasing and decreasing position-to-pressure (PTP) curves via measurement of the position, at a predetermined time, in response to a series of respectively increasing and decreasing pressure step commands. The controller adjusts the PTP curves using a calibrated set of offsets, locates a PTP point in a hysteresis range between the adjusted PTP curves, and controls the device using the PTP point. The offsets may include a temperature of the fluid, velocity of the linear actuator, and/or an engine speed.

First claim

The invention claimed is:

1. A system comprising:
hydraulic fluid;
an actuatable device that includes a linear actuator, wherein the linear actuator is moveable via the hydraulic fluid to thereby actuate the actuatable device;
a position sensor operable to measure a position of the linear actuator and output the measured position as a position signal; and
a controller in electrical communication with the actuatable device and the position sensor, wherein the controller is programmed to:
transmit a series of respectively increasing and decreasing pressure step commands to the linear actuator;
generate respective increasing and decreasing position-to-pressure (PTP) curves at a predetermined time using the measured position in response to transmitting the series of respectively increasing and decreasing pressure step commands;
adjust the increasing and decreasing PTP curves using a calibrated set of offsets;
locate a PTP point in a hysteresis range between the adjusted increasing and a decreasing PTP curves; and
control the actuatable device using the located PTP point.

2. The system of claim 1 , wherein the actuatable device is a clutch and the linear actuator is a clutch apply piston.

3. The system of claim 2 , wherein the system is an automotive transmission.

4. The system of claim 3 , wherein the automotive transmission is a dual clutch transmission (DCT), and wherein the clutch is one of two separate input clutches which, when applied, connect the DCT to an engine.

5. The system of claim 1 , wherein the calibrated set of offsets includes at least one of a temperature of the hydraulic fluid and a linear velocity of the linear actuator.

6. The system of claim 5 , wherein the system is part of a vehicle having an engine, and wherein the calibrated set of offsets includes a speed of the engine, the temperature of the hydraulic fluid, and the linear velocity of the linear actuator.

7. The system of claim 1 , wherein the controller is further programmed to construct a baseline set of the increasing and a decreasing PTP curves once every predetermined number N of key cycles of the vehicle, and wherein N>1000.

8. The system of claim 1 , wherein the predetermined time is the earlier of a velocity of the linear actuator slowing below a threshold velocity and an expiration of a timer of the controller that measures a duration of each of the increasing and decreasing pressure step commands.

9. A vehicle comprising:
an engine;
a transmission;
an input clutch that selectively connects the engine to the transmission;
hydraulic fluid;
a clutch that includes a clutch apply piston, wherein the clutch is an actuatable device that is actuated by the clutch apply piston via the hydraulic fluid;
a position sensor operable to measure a position of the clutch piston and output the measured position as a position signal; and
a controller in electrical communication with the actuatable device and the position sensor, wherein the controller is programmed to:
transmit a series of respectively increasing and decreasing pressure step commands to the clutch apply piston;
generate respective increasing and decreasing position-to-pressure (PTP) curves at a predetermined time using the measured position in response to transmitting the series of respectively increasing and decreasing pressure step commands;
adjust the increasing and decreasing PTP curves using a calibrated set of offsets;
locate a PTP point in a hysteresis range between the adjusted increasing and a decreasing PTP curves; and
control the actuatable device using the located PTP point.

10. The vehicle of claim 9 , wherein the transmission is a dual clutch transmission (DCT), and wherein the input clutch is one of two separate input clutches which, when applied, connect the DCT to the engine.

11. The vehicle of claim 9 , wherein the calibrated set of offsets includes at least one of a temperature of the hydraulic fluid and a linear velocity of the clutch piston.

12. The vehicle of claim 11 , wherein the calibrated set of offsets includes the temperature of the fluid and the linear velocity of the clutch piston.

13. The vehicle of claim 12 , wherein the calibrated set of offsets further includes a speed of the engine.

14. The vehicle of claim 9 , wherein the controller is further programmed to construct a baseline set of the increasing and decreasing PTP curves once every predetermined number N of key cycles of the vehicle, and wherein N>1000.

15. The vehicle of claim 9 , wherein the predetermined time is the earlier of a velocity of the linear actuator slowing below a threshold velocity and expiration of a timer of the controller that measures a duration of each of the increasing and decreasing pressure step commands.

16. A method for use in a system having hydraulic fluid, an actuatable device that includes a linear actuator moveable via the hydraulic fluid, a position sensor operable to measure a position of the linear actuator and output the measured position as a position signal, and a controller in electrical communication with the actuatable device and the position sensor, the method comprising:
transmitting a series of respectively increasing and decreasing pressure step commands to the linear actuator; generating respective increasing and decreasing position-to-pressure (PTP) curves at a predetermined time using the measured position in response to transmitting the series of respectively increasing and decreasing pressure step commands; adjusting the increasing and decreasing PTP curves using a calibrated set of offsets; locating a PTP point in a hysteresis range between the adjusted increasing and decreasing PTP curves; and controlling the actuatable device using the located PTP point.

17. The method of claim 16 , wherein the system is an automotive transmission system, the actuatable device is a clutch, and the linear actuator is a clutch apply piston.

18. The method of claim 16 , wherein adjusting the increasing and decreasing PTP curves using a calibrated set of offsets includes adjusting the increasing and decreasing PTP curves using a temperature of the fluid and a linear velocity of the linear actuator.

19. The method of claim 18 , wherein adjusting the increasing and decreasing PTP curves using a calibrated set of offsets further includes adjusting the increasing and decreasing PTP curves using a speed of an engine.

20. The method of claim 16 , further comprising constructing a baseline set of the PTP curves via the controller once every predetermined number N of key cycles of a vehicle having the system, and wherein N>1000.

Assignees

• Gm Global Tech Operations Inc

Inventors

• Moorman Steven P
• Fell Brandon
• Nowak Mateusz

Classifications

• F16D25/14 Primary

  Fluid pressure control · CPC title

• B60W10/02

  including control of driveline clutches · CPC title

• F16D25/06

  in which the fluid actuates a piston incorporated in, {i.e. rotating with} the clutch (F16D25/02 takes precedence) · CPC title

• B60W20/40

  Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers {(power-up or power-down of the driveline B60W30/192)} · CPC title

• F16D48/02

  Control by fluid pressure · CPC title