Brake Pressure Release Timing for Vehicle Stop Swing Back
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Solution Overview
Problem
Existing vehicle control devices are ineffective in reducing swing back when a vehicle stops, especially when the deceleration immediately before stop is large.
Innovation Solution
A vehicle control device that includes a deceleration detection unit, a stop schedule specifying unit, a brake control unit, and a threshold value determination unit. The threshold value determination unit adjusts the threshold value for brake pressure reduction based on detected deceleration, road gradient, and vehicle weight to optimize brake pressure reduction timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the deceleration immediately before stop is reduced, then the swing back is reduced, but the stopping distance increases and stopping time is extended
Solution Approach 1:
The control device starts reducing brake pressure in advance when the vehicle speed reaches a predetermined threshold value before complete stop. This preliminary action allows the brake pressure to be gradually reduced before the vehicle comes to a halt, preventing sudden deceleration changes that cause swing back while still achieving timely stop. The threshold value is set based on vehicle speed to optimize the timing of brake pressure reduction.
Solution Approach 2:
The brake pressure control is made dynamic by adjusting the reduction timing based on real-time vehicle speed. The control device uses a threshold value determination unit that sets the brake pressure reduction threshold based on current vehicle speed conditions. This dynamic adjustment allows the system to adapt to different driving conditions and vehicle states, optimizing both swing back reduction and stopping performance.
2Device complexity
If the brake pressure is reduced when vehicle speed reaches a fixed threshold, then the control is simple, but the swing back cannot be sufficiently reduced when deceleration is large
Solution Approach 1:
The control device changes the threshold parameter for brake pressure reduction based on vehicle speed conditions. Instead of using a fixed speed threshold, the threshold value determination unit adjusts the threshold based on real-time vehicle speed and deceleration conditions. This parameter adaptation allows the system to effectively reduce swing back across various driving scenarios while maintaining relatively simple control logic.
Solution Approach 2:
The control device incorporates feedback by continuously monitoring vehicle speed and deceleration conditions. The threshold value determination unit uses this feedback information to dynamically adjust the brake pressure reduction threshold. This feedback mechanism enables the system to respond appropriately to different deceleration magnitudes and vehicle states, effectively reducing swing back without requiring complex control algorithms.
Data Source
AI summary
A vehicle control device incudes a deceleration detection unit that detects a deceleration of a vehicle, a stop schedule specifying unit that specifies that the vehicle is scheduled to stop, a brake control unit that starts reducing a brake pressure when a vehicle speed of the vehicle becomes equal to or less than a threshold value, and a threshold value determination unit that determines the threshold value such that the threshold value increases as the deceleration detected by the deceleration detection unit increases after the stop schedule specifying unit specifies that the vehicle is scheduled to stop.