Shift-by-Wire Controller Tilt-Adaptive Motor Speed
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Solution Overview
Problem
Conventional shift-by-wire systems generate significant noise during the release of the lock mechanism, particularly when the vehicle is on a slope, due to the rapid release of the locking torque, which is not effectively addressed in existing technologies.
Innovation Solution
A controller that estimates the vehicle's tilt and adjusts the target rotation speed of the motor to suitably unlock the lock mechanism, reducing noise by slowing down the motor's rotation when the vehicle is on a slope, thereby easing the torque release and minimizing gear noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the shift position is switched quickly by the shift-by-wire system, then the shift position switching speed is improved, but the noise generated at lock release time increases
Solution Approach 1:
The patent applies dynamics by making the motor rotation speed variable rather than fixed. The control device dynamically adjusts the target rotation speed based on real-time tilt angle detection, allowing the system to optimize between switching speed and noise reduction depending on the vehicle's operational context. This is implemented through the control device receiving tilt angle information and selectively setting target rotation speeds based on whether the tilt angle exceeds a threshold value.
Solution Approach 2:
The patent changes the parameter of motor rotation speed based on the tilt angle parameter. When the tilt angle exceeds a predetermined threshold, the system changes to a lower target rotation speed to reduce noise during lock release. This parameter change approach allows the system to adapt its operational characteristics to environmental conditions, specifically resolving the contradiction between fast switching and noise reduction by selecting appropriate speed parameters contextually.
2Object-generated harmful factors
If the target rotation speed is reduced to minimize noise, then the noise at lock release time is reduced, but the shift position switching speed decreases
Solution Approach 1:
The system changes the motor rotation speed parameter based on tilt angle conditions. When the tilt angle is within an acceptable range, the system uses a higher target rotation speed for fast switching. When the tilt angle exceeds the threshold, it switches to a lower target rotation speed to minimize noise. This conditional parameter change resolves the contradiction by applying different speed settings to different operational scenarios.
Solution Approach 2:
The system dynamically selects between different rotation speed modes based on real-time tilt angle detection. This dynamic adaptation allows the system to maintain high switching speed during normal conditions while automatically reducing speed to minimize noise when tilt conditions indicate potential for excessive noise generation during lock release.
3Productivity
If the motor rotates at high speed for quick unlocking, then the productivity is improved, but the friction and noise between lock mechanism components increases
Solution Approach 1:
The control device changes the motor rotation speed parameter based on tilt angle conditions. When tilt angle exceeds the threshold, the system reduces the target rotation speed during the unlocking phase, which directly reduces the friction and noise between lock mechanism components while still achieving the unlocking function. This parameter adjustment resolves the contradiction between high-speed unlocking and component protection.
Solution Approach 2:
The system performs preliminary detection of the tilt angle before initiating the unlocking operation. Based on this preliminary information, it pre-determines the appropriate target rotation speed, allowing it to prevent excessive friction and noise before they occur by selecting a suitable speed profile in advance, rather than reacting after the problem manifests.
Data Source
AI summary
A shift-by-wire system, including a controller that includes a motor driver, and a microcomputer connected to the motor driver to control a motor that drives a control object. The control object has a park lock mechanism having a lock state and an unlock state. The lock state and the unlock state are switched according to an operation position of the control object. The controller is configured to estimate a tilt of a vehicle, detect whether the lock mechanism is in the lock state or in the unlock state, and adjust a target rotation speed of the motor according to the estimated tilt when the operation position of the control object is changed for switching the lock state to the unlock state.