Lockup Clutch Slip Learning for Adaptive Hydraulic Pressure Control
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Solution Overview
Problem
Existing control apparatuses for vehicles with fluid transmission devices and lockup clutches struggle to accurately correct hydraulic pressure command values when the slip amount of the lockup clutch becomes zero, leading to inappropriate correction of hydraulic pressure during slip control.
Innovation Solution
A control apparatus that includes a lockup-clutch control portion for executing slip control by setting a target slip amount and a learning control portion that adjusts the command value of fluid pressure based on a correction amount, with the given range set depending on the target slip amount to avoid including zero in the convergence range, ensuring accurate correction of hydraulic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the given range for convergence determination includes zero slip amount, then the convergence check becomes simpler, but the learning correction becomes inaccurate when the lockup clutch is fully engaged
Solution Approach 1:
The patent applies local quality by making the given range variable rather than fixed. The range is adjusted based on the target slip amount, creating different convergence criteria for different operating conditions. This ensures that zero slip amount is excluded from the convergence determination when the target is non-zero, preventing inaccurate learning corrections while maintaining operational simplicity.
Solution Approach 2:
The patent implements dynamics by making the given range adaptive to the target slip amount. Instead of using a static convergence threshold, the system dynamically adjusts the range based on current operating conditions, allowing the convergence criteria to change with the target slip amount and preventing false convergence detection.
2Productivity
If the lockup clutch is placed into a fully engaged state with zero slip amount, then the clutch engagement is complete, but the feedback control cannot provide accurate correction data for learning
Solution Approach 1:
The patent applies preliminary anti-action by proactively preventing the use of zero slip amount data for learning purposes. The system anticipates the problem of inaccurate correction data and preemptively excludes such data points from the learning process by designing the convergence determination to exclude zero when the target is non-zero, thereby maintaining learning control reliability.
3Device complexity
If a fixed given range is used for convergence determination, then the control logic is simpler, but it cannot adapt to different target slip amounts and may include zero in the range
Solution Approach 1:
The patent implements dynamics by transitioning from a fixed given range to a dynamic range that adapts to different target slip amounts. The given range is calculated based on the target slip amount, allowing the convergence criteria to automatically adjust to different operating conditions while maintaining relatively simple control logic.
Solution Approach 2:
The patent applies parameter changes by making the given range a variable parameter rather than a constant. The range is modified based on the target slip amount parameter, allowing the system to adapt to different operating conditions without fundamentally changing the control logic structure.
Data Source
AI summary
A control apparatus for a vehicle provided with (i) a power source, (ii) drive wheels and (iii) a fluid transmission device disposed between the power source and the drive wheels and including a lockup clutch to which a fluid pressure is supplied. A feedback control is executed for correcting a command value of the fluid pressure by a correction amount such that an actual value of a slip amount of the lockup clutch becomes substantially equal to the target value of the slip amount in a slip control. When the actual value has been converged into a given range with respect to the target value, the correction amount is obtained, and the command value for a next execution of the slip control is corrected by learning with use of the obtained correction amount. The given range is set depending on the target value of the slip amount.