Lock-up Clutch Control Device Dynamic Gain Adjustment
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Solution Overview
Problem
Existing lock-up clutch control devices face challenges in stabilizing and improving response characteristics across a wide rotational speed range due to varying clutch characteristics and difficulties in adequately varying weight assignments based on vehicle or engine states.
Innovation Solution
A lock-up clutch control device that adjusts the integral term gain of the hydraulic pressure command value based on the rotational speed and temperature of the input shaft and working oil, ensuring the actual rotational speed difference between the motor and input shaft matches the target slip speed, thereby enhancing stability and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If feedback control is executed using fixed gain compensators across a wide rotation range, then the control structure remains simple, but the response characteristics deteriorate at different rotational speeds
Solution Approach 1:
The patent applies dynamics by making the feedback compensator gains variable rather than fixed. The first feedback compensator (PD controller) and second feedback compensator (PID controller) have their gains dynamically adjusted based on the rotational speed of the input shaft. This allows the control system to adapt its characteristics to different operating conditions, improving response at both low and high speeds without excessive complexity
Solution Approach 2:
The patent changes the parameters (gains) of the feedback compensators based on the rotational speed. Specifically, the assignment ratios of command values from the first and second feedback compensators are adjusted according to the input shaft rotational speed, allowing optimal performance across the entire rotation range while maintaining a relatively simple control structure
2Speed
If switching between different feedback compensators is performed based on vehicle state, then the response during starting is improved, but the stability across wide rotation range deteriorates
Solution Approach 1:
The patent makes the compensator selection dynamic by continuously adjusting the assignment ratio based on rotational speed rather than using fixed switching thresholds. This dynamic adjustment maintains stability across the wide rotation range while preserving transient response improvement during starting conditions
Solution Approach 2:
The patent uses a blended approach where both the first and second feedback compensators contribute to the control output simultaneously, with their assignment ratios adjusted according to rotational speed. This partial action from both compensators maintains stability while preserving the transient response benefits of the PID controller during starting
Data Source
AI summary
A lock-up clutch control device that sets a hydraulic pressure command value for a lock-up clutch as a starting device together with a pump impeller coupled to a motor of a vehicle and a turbine runner coupled to an input shaft of a transmission such that an actual rotational speed difference between the motor and the input shaft coincides with a target slip speed that matches a state of the vehicle, and that controls the lock-up clutch based on the hydraulic pressure command value.