Automatic Transmission Control via Phase-Shifted Feedback
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Solution Overview
Problem
Existing automatic transmission control systems fail to secure full engagement of frictional engagement elements due to variations in hydraulic pressure, leading to rotational speed discrepancies between the input shaft and target values.
Innovation Solution
An automatic transmission control apparatus that includes a frictional engagement element, a hydraulic pressure supplying section, a progression state judging section, and both rotational speed change rate and feedback control sections to ensure the engagement of the frictional engagement element by controlling hydraulic pressure based on target rotational speed and progression state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If feedback control is performed using only rotation change rate as target value, then the control response is fast, but full engagement of frictional engagement element is not secured and rotational speed may not reach synchronous speed
Solution Approach 1:
The control process is divided into two distinct phases: a first feedback control phase using only rotation change rate for fast response, and a second feedback control phase using both rotation change rate and rotational speed for reliable engagement. This segmentation allows each phase to optimize for its specific objective without compromise.
Solution Approach 2:
The system performs preliminary action by implementing the first feedback control phase that focuses on rotation change rate before transitioning to the second phase. This preliminary control establishes the foundation for subsequent precise engagement control, ensuring the system is properly prepared for full engagement.
2Measurement precision
If feedback control focuses on rotation change rate to attain target value, then control precision is improved, but the frictional engagement element may not be fully engaged due to hydraulic pressure variations
Solution Approach 1:
The control strategy is segmented into two phases: first feedback control for rotation change rate precision, and second feedback control for engagement precision. This segmentation allows the system to prioritize rotation control initially, then transition to ensuring complete engagement without compromising either precision requirement.
Solution Approach 2:
The system maintains continuous useful action by seamlessly transitioning from the first feedback control phase to the second feedback control phase. The control process continues without interruption, with the second phase building upon the foundation laid by the first phase to ensure complete engagement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively secures full engagement of the frictional engagement element by controlling hydraulic pressure to match the target rotational speed, preventing excessive overshoot and ensuring smooth, stable engagement operations.
Implementation Method 1
a hydraulic pressure supplying section configured to supply a hydraulic pressure to the frictional engagement element
Implementation Method 2
a frictional engagement element arranged to engage in a running state when the automatic transmission is shifted from a neutral state
Data Source
AI summary
An automatic transmission control apparatus includes: a frictional engagement element; a hydraulic pressure supplying section configured to supply a hydraulic pressure to the frictional engagement element; a progression state judging section configured to judge a progression state of the engagement of the frictional engagement element; a rotational speed change rate control section configured to control the hydraulic pressure so that a change rate of a rotational speed of an input shaft of the automatic transmission becomes equal to a target change rate, from when the engagement of the frictional engagement element is started; and a rotational speed feedback control section configured to perform a feedback control of the hydraulic pressure so that the rotational speed of the input shaft of the automatic transmission becomes equal to a target rotational speed, from when the progression state judging section judges a predetermined progression state.