Vehicle Control Device Shift Range Switching Safety
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Solution Overview
Problem
Existing vehicle control systems lack effective safety measures when an abnormality occurs in the shift range switching system, particularly when the driver is not present, leading to potential unsafe vehicle behaviors such as slipping or unintended movement during or after parking.
Innovation Solution
The vehicle control device integrates a shift control unit and a brake control unit, which coordinate to ensure safe operation by monitoring abnormalities in the shift-by-wire system and engaging the electric brake system to prevent unsafe conditions, even when the driver is not present, by controlling the motor and brake actuators and maintaining power until the shift range is securely set to the P range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brake control unit power is turned off immediately when the start switch is turned off, then the vehicle startup process is simplified and faster, but safety is compromised because the brake system cannot respond to abnormalities occurring during shift range switching
Solution Approach 1:
The brake control unit power is turned off after confirming that the shift range switching system has completed switching to the P range. This preliminary confirmation ensures that the brake system remains active long enough to respond to any abnormalities that might occur during the critical shift range switching period, while still turning off power in a timely manner after safety is ensured.
2Reliability
If the brake control unit power is maintained until shift range switching is complete, then safety is improved by allowing abnormality response, but the vehicle startup process becomes longer and more complex
Solution Approach 1:
The brake control unit receives feedback from the shift control unit regarding the completion status of shift range switching. Based on this feedback, the brake control unit determines when to turn off its power. This feedback mechanism allows for automated coordination between systems, reducing the need for complex control logic while ensuring safety.
3Reliability
If the brake system remains active during shift range switching, then abnormality response capability is improved, but energy consumption increases
Solution Approach 1:
The brake control unit power is turned off after confirming that the shift range switching system has completed switching to the P range. This preliminary confirmation ensures that the brake system remains active long enough to respond to any abnormalities that might occur during the critical shift range switching period, while still turning off power in a timely manner after safety is ensured.
Data Source
AI summary
A vehicle control device controls a vehicle control system, which includes a shift range switching system configured to switch a shift range by controlling a drive of a shift actuator, and an electric brake system configured to brake a vehicle by controlling a drive of a brake actuator. The vehicle control device includes a shift control unit and a brake control unit. The shift control unit controls a drive of the shift actuator. The brake control units control a drive of a brake actuator. When the start switch of the vehicle is turned off, the power of the brake control units is turned off after the shift range switching system completes switching to the P range.