Vehicle Drive Mechanism Stopper Learning With Torque Limiting
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Solution Overview
Problem
In vehicle drive mechanisms, such as variable compression ratio mechanisms, learning the output of a sensor at a stopper position quickly while limiting impact force is challenging, especially with low-rigidity stoppers, which can be damaged by high rotation speeds and require longer learning times to prevent damage.
Innovation Solution
A control device and method that prioritize learning for high-rigidity stoppers first, then adjust motor torque levels when transitioning to low-rigidity stoppers to minimize impact force and shorten learning time, using a sensor to monitor and adjust actuator operation variables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the control shaft is brought into contact with the stopper at an increased rotation speed to shorten learning time, then the learning time is reduced, but a significant impact force is added to the stopper which may cause damage
Solution Approach 1:
The control device performs preliminary actions by first learning the stopper position at high rotation speed to establish a reference point, then uses this learned position to subsequently limit rotation speed during normal operation, preventing excessive impact forces while maintaining efficient learning capability
Solution Approach 2:
The system dynamically changes the rotation speed parameter based on the learning stage - using high rotation speed during the learning phase to minimize time loss, and switching to limited rotation speed during normal operation to protect the stopper from damage
2Reliability
If the rotation speed is lowered to prevent damage to the stopper, then the stopper is protected from impact damage, but the learning time increases
Solution Approach 1:
The system performs a one-time preliminary learning action at high speed to establish the stopper position reference, after which normal operation can proceed with speed limitation, thus sacrificing minimal time for long-term reliability
3Reliability
If the timing for changing motor torque is advanced to prevent contact before torque limitation, then contact protection is improved, but the learning time cannot be shortened as much as possible
Solution Approach 1:
The control device uses feedback from the learned stopper position to dynamically adjust motor torque timing - once the stopper position is learned, the system feedbacks this information to optimize torque application timing, balancing protection and efficiency
Data Source
AI summary
The present invention relates to a control device and to a control method for a vehicle drive mechanism including a moving body having a movability range regulated by two stoppers, and a sensor which senses a position of the moving body. The control device of the present invention learns an output of the sensor corresponding to a contact state of a high-rigidity stopper, and limits, to a lower level, an operation variable of the actuator for moving the moving body toward a low-rigidity stopper along with an increase in an amount of change in the output of the sensor from the contact state of the high-rigidity stopper. Then, the control device learns the output of the sensor corresponding to the contact state of the low-rigidity stopper, and controls the actuator based on the output of the sensor learned at both the stopper positions.