Torque-Stroke Curve Learning for Electric Motor Dry Clutch
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Solution Overview
Problem
In dual clutch transmission systems, accurately learning the torque-stroke curve is challenging due to variations caused by engine torque fluctuations and uncertainties in clutch temperature, especially in dry clutch systems where temperature characteristics are inaccurate, leading to potential abnormality in transmission systems.
Innovation Solution
A method involving a control unit that calculates a position change value to adjust the torque-stroke curve, considering environmental factors like friction and temperature, by generating a virtual curve and applying a probability-based adjustment to ensure accurate learning of the curve, even with constant engine torque variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the torque-stroke curve is learned using conventional methods, then the clutch transmission torque can be predicted based on clutch movement distance, but the learning accuracy deteriorates due to engine torque fluctuations and clutch temperature modeling errors
Solution Approach 1:
The control unit performs preliminary actions by storing multiple torque-stroke curves corresponding to different clutch temperatures before actual operation. When learning is needed, the system selects the appropriate pre-stored curve based on current temperature conditions, avoiding the need to learn during transient temperature states when accuracy would be poor.
Solution Approach 2:
The invention changes the parameter of clutch temperature as the basis for selecting different torque-stroke curves. Instead of using a single fixed curve, the system maintains multiple curves parameterized by temperature levels and selects the appropriate one based on real-time temperature measurement, thereby adapting to temperature variations without compromising learning accuracy.
2Measurement precision
If multiple torque-stroke curves are stored for different clutch temperatures, then the accuracy under varying temperature conditions is improved, but the device complexity increases
Solution Approach 1:
The control unit manages complexity by organizing torque-stroke curves according to temperature parameters. Instead of storing arbitrary multiple curves, the system structures data by temperature levels, allowing efficient selection and management. This parameter-based organization reduces the cognitive and computational complexity of handling multiple curves.
Solution Approach 2:
The system performs preliminary organization of torque-stroke curves during manufacturing or initial setup, categorizing them by temperature conditions. This pre-structuring of data eliminates the need for complex real-time processing during operation, as the control unit simply needs to measure temperature and select the corresponding pre-organized curve.
3Reliability
If the clutch position is adjusted to follow the torque-stroke curve, then the transmission torque control is improved, but the system becomes sensitive to torque errors and temperature modeling inaccuracies
Solution Approach 1:
The invention addresses sensitivity to torque and temperature variations by changing the approach from using a single torque-stroke curve to selecting from multiple temperature-specific curves. This parameter-based selection reduces sensitivity to temperature modeling errors, as the system adapts to actual temperature conditions rather than relying on inaccurate predictions.
Solution Approach 2:
The control unit implements feedback by measuring actual clutch temperature and selecting the appropriate torque-stroke curve based on this measurement. This closed-loop approach allows the system to adapt to real-time conditions, reducing sensitivity to initial torque errors and temperature modeling inaccuracies while maintaining reliable torque control.
Data Source
AI summary
A method for learning a torque-stroke (T-S) curve of an electric motor controlled dry clutch system is disclosed. The method includes calculating a position change value A for allowing a position change point P3 corresponding to an arbitrary torque y3 on a previous T-S curve C1 to follow-up and be moved to an expectation T-S curve C3, by a control unit, calculating a probability Pr_X3 to allow the position change value A to consider various environmental factors of a clutch within a valid range, and multiplying the probability Pr_X3 to the position change value A to calculate a final position change value A, by the control unit, and calculating a new point P3 by applying the final position change value A to the position change point P3 of the previous T-S curve C1, and generating a final T-S curve connecting the new point P3 and a touch point to learn, by the control unit.