Control method for an electric motor-activated clutch mechanism
AssigneeGeneral Motors Corporation
InventorShushan Bai
Life of this patent
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Abstract
An improved control method activates an electric motor to drive a torque-to-thrust converter for controlling the torque capacity of a clutch mechanism. The control utilizes a model-based feed-forward control in combination with a closed-loop position feed-back control. The desired clutch torque capacity is characterized in terms of a desired motor position, and the feed-forward control models the motor speed and position response to changes in the desired motor position. The modeled speed and position, in turn, are used to create a feed-forward command, and the feed-forward command is combined with a feedback command based on actual position error.
Claims3
A method of operation for an electric motor activated clutch mechanism, where an output shaft of the electric motor drives a torque-to-thrust converter that is mechanically coupled to the clutch mechanism, the method comprising the steps of:
- developing a feed-forward activation value for achieving the requested angular position based on a model of the motor and on frictional characteristics of the torque-to-thrust converter by:
- modeling a desired position response and a desired speed response of said motor to changes in the requested angular position;
- determining a first motor activation value for achieving the modeled position response, and a second motor activation value for achieving the modeled speed response;
- and
- summing the first and second motor activation values to form said feedforward activation values;
- activating the motor in accordance with said feed-forward activation value;
- measuring an angular position of the motor output shaft;
- and
- adjusting said feed-forward activation value in accordance with a feed-back adjustment based on a deviation of the measured angular position from the requested angular position.
Dependencies are inferred from the claim text.