Model-based transmission upshift control with engine torque management

• US 6,364,811 B1
• Filed: 06/22/2000
• Issued: 04/02/2002
• Est. Priority Date: 03/20/2000
• Status: Expired due to Term

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Nitz, Larry Theodore, Steinmetz, Todd M, Runde, Jeffrey Kurt, Robinson, Timothy Alan, Hubbard, Gregory A
• Primary Examiner(s): ESTREMSKY, SHERRY LYNN
• Application Number:
  US09/598,283
• Time in Patent Office: 649 Days
• Field of Search: 477/107, 477/143, 477/156, 477/164
• US Class Current: 477/143
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/115 with planetary gears
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 2710/1016 Input speed change rate
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

An improved control for an automatic transmission upshift, wherein the engine output torque and on-coming clutch pressure are coordinated during the shift based on an inverse dynamic model of the transmission to achieve a desired output torque trajectory. The desired output torque trajectory is influenced by operator demand, and an initial value of the desired output torque trajectory is used along with the engine output torque to develop an input acceleration trajectory. The inverse dynamic model of the transmission is used (1) to determine an engine torque command that will achieve both the input acceleration trajectory and the desired output torque trajectory, and (2) to determine a feed-forward pressure command for the on-coming clutch that will produce the input acceleration trajectory, given the engine torque command. The desired output torque trajectory and the engine output torque are used to determine the expected input speed, and a feed-back control term based on the deviation of the measured input speed from the expected input speed is used to adjust the on-coming clutch pressure command to account for model errors. Finally, the closed-loop feedback error is used to enable adaptive correction of the feed-forward control so that the feed-forward clutch pressure more nearly produces the commanded input shaft acceleration.

Claims

1. A method of controlling an on-coming clutch pressure during an inertia phase of an upshift of a motor vehicle automatic transmission having an input shaft coupled to a vehicle engine and an output shaft coupled to drive the vehicle, the method comprising the steps of:

developing a desired torque trajectory of the output shaft;

developing a desired acceleration trajectory of the input shaft;

applying the desired torque trajectory and the desired acceleration trajectory to an inverse dynamic model of the transmission to determine an engine output torque command;

commanding engine output torque in accordance with the determined engine output torque command;

applying the desired acceleration trajectory to the inverse dynamic model of the transmission during the inertia phase of the upshift to obtain an estimate of a required on-coming clutch pressure at the commanded engine output torque;

developing a feed-forward clutch pressure command based on the estimated clutch torque; and

developing on-coming clutch pressure in accordance with the pressure command.

2. The method of claim 1, wherein the step of applying the desired acceleration trajectory to the inverse dynamic model of the transmission includes the steps of:

delaying the commanded engine output torque and the desired acceleration trajectory; and

applying the delayed desired acceleration trajectory and the delayed commanded engine ouput torque to the inverse dynamic model to obtain the estimate of the required on-coming clutch pressure.

3. The method of claim 1, including the steps of:

measuring a speed of the input shaft;

determining an expected speed of the input shaft; and

adjusting the pressure command in accordance with a feed-back adjustment based on a deviation of the measured speed from said expected speed to compensate for errors in said dynamic model.

4. The method of claim 3, wherein the step of determining an expected speed of the input shaft comprises the steps of:

delaying the output torque trajectory to estimate the expected output torque;

computing an expected input acceleration based on the expected output torque and the engine output torque; and

and integrating the expected input acceleration to determine the expected speed of the input shaft.

5. The method of claim 1, where the step of applying the desired torque trajectory and the desired acceleration trajectory to an inverse dynamic model of the transmission to determine an engine output torque command includes the steps of:

determining a desired output acceleration trajectory based on the desired output torque trajectory; and

applying the desired output acceleration trajectory, the desired torque trajectory and the desired input acceleration trajectory to the inverse dynamic model to determine the engine output torque command.