Vehicle Brake Control with Pseudo-Abnormal State Switching
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Solution Overview
Problem
Existing vehicle brake systems face a shortage of braking force due to prolonged detection times for abnormal states in the downstream hydraulic-pressure control mechanism, leading to insufficient braking in automated driving states.
Innovation Solution
The implementation of a brake system that includes a pseudo-abnormal-state detecting mechanism, which rapidly switches to the upstream hydraulic-pressure control mechanism when a pseudo abnormal state is detected, ensuring a continuous braking force by executing regenerative cooperative control with the downstream hydraulic braking force and upstream hydraulic braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the brake system waits to switch to the upstream hydraulic-pressure control mechanism until an abnormal state is confirmed, then the system avoids unnecessary switching, but the braking force becomes insufficient during the detection period
Solution Approach 1:
The system performs preliminary detection of a pseudo abnormal state before confirming a full abnormal state. When the downstream hydraulic-pressure control mechanism shows signs of abnormality (pseudo abnormal state), the system proactively prepares to switch to the upstream mechanism, thereby reducing the time period during which braking force is insufficient.
2Reliability
If the system switches to the upstream hydraulic-pressure control mechanism early when a pseudo abnormal state is detected, then the braking force shortage is reduced, but the system complexity increases due to multiple detection mechanisms
Solution Approach 1:
The abnormality detection is segmented into two levels: pseudo abnormal state detection and full abnormal state detection. The pseudo abnormal state detection monitors parameters that may indicate future abnormalities, allowing the system to prepare for switching before a full abnormal state occurs. This segmentation enables early preparation without requiring complete system redundancy.
Solution Approach 2:
The system performs preliminary detection of a pseudo abnormal state before confirming a full abnormal state. When the downstream hydraulic-pressure control mechanism shows signs of abnormality (pseudo abnormal state), the system proactively prepares to switch to the upstream mechanism, thereby reducing the time period during which braking force is insufficient.
3Device complexity
If the system uses a single downstream hydraulic-pressure control mechanism, then the system is simpler, but the braking force becomes insufficient when an abnormal state occurs
Solution Approach 1:
The upstream hydraulic-pressure control mechanism is designed to serve dual purposes: it operates as a supplementary mechanism during normal operation and as a primary backup mechanism when the downstream mechanism fails. This multi-functionality allows the system to maintain simplicity while ensuring reliability, as the upstream mechanism can take over completely when needed.
Data Source
AI summary
A vehicle brake system, including: a first-braking-force control mechanism configured to control a first braking force, a second-braking-force control mechanism configured to control a second braking force, an abnormal-state detecting device configured to detect whether the first-braking-force control mechanism is in an abnormal state, a pseudo-abnormal-state detecting device configured to detect whether the first-braking-force control mechanism is in a pseudo abnormal state in which the first-braking-force control mechanism is suspected to be in the abnormal state, and a controller including a pseudo abnormal state controller configured to control the second-braking-force control mechanism in an operating state of the first-braking-force control mechanism so as to control the second braking force when the pseudo-abnormal-state detecting device detects that the first-braking-force control mechanism is in the pseudo abnormal state.