Brake Control Unit Curve Radius Pressure Limiting
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Solution Overview
Problem
Current vehicle brake systems face instability due to high brake requests from external driver assistance systems, particularly in situations where the brake demands are excessive, potentially leading to wheel slip and loss of vehicle stability.
Innovation Solution
A control unit for an electrically controlled pressurized-fluid brake system that limits brake pressure based on the curve radius of the vehicle's trajectory, independent of road friction coefficients, to prevent excessive deceleration and maintain stability, using a detection system like radar or optical sensors for curve determination and arithmetic functions or tables to set pressure limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external driver assistance systems send high brake requests to regulate vehicle speed or maintain distance, then the braking performance is improved, but the vehicle stability deteriorates due to excessive deceleration in curves
Solution Approach 1:
The brake pressure limitation is not fixed but dynamically adapted based on the detected curve radius. The control unit continuously monitors the vehicle's trajectory and adjusts the maximum allowable brake pressure accordingly, allowing higher pressures on straight roads and lower pressures in tight curves, thus resolving the contradiction between braking performance and stability
Solution Approach 2:
The system changes the parameter of brake pressure based on the curve radius parameter. By detecting the curve radius and using it to determine an appropriate pressure limit, the system adapts the braking characteristics to the current driving situation, enabling effective braking on straight roads while preventing instability in curves
2Stability of the object's composition
If brake pressure is limited based on curve radius, then vehicle stability is maintained, but the braking force is reduced in high-friction situations
Solution Approach 1:
The system applies partial braking force limitation only when necessary (in curves), rather than continuously limiting the brake pressure. The curve radius-based limitation is selectively applied based on the detected trajectory, allowing full braking force to be used on straight roads or in low-curvature situations where stability is not a concern
Data Source
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AI summary
To operate an electrically controlled pressurized-fluid brake System, an external brake request signal is received, a curve radius of a vehicle track of the vehicle is determined, at least one limit value is determined based on the curve radius, at least one variable representing a brake pressure to be supplied to wheel brakes is compared with the at least one limit value, the at least one variable is limited based on the comparison, the at least one variable is outputted, and braking pressure is supplied to the wheel brakes based on the outputted at least one variable.