EMB Power Supply Layout for Braking Force Retention
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Solution Overview
Problem
Existing power systems for electronic mechanical brake systems suffer a 50% loss in total braking force when an abnormality occurs in one of the power apparatuses, leading to inadequate deceleration.
Innovation Solution
A power supply apparatus with a redundant power line configuration that maintains minimum required deceleration by distributing braking forces based on front and rear wheel ratios, using auxiliary controllers and low voltage batteries to ensure power delivery to critical components even in the event of power line abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a redundant power system with X-split structure is used to supply power to electronic mechanical brakes, then power supply reliability is improved, but when an abnormality occurs in one power apparatus, 50% of total braking force is lost
Solution Approach 1:
The power supply system is segmented into three separate power lines (first, second, and third power lines) instead of two, with each line independently supplying power to specific wheel controllers. This segmentation allows the system to maintain partial braking functionality on a per-wheel basis when one power line fails, rather than losing entire halves of the braking system.
Solution Approach 2:
Each power line is assigned to supply power to specific wheel controllers based on local requirements. The first power line supplies the left front wheel controller, the second power line supplies the right front wheel controller, and the third power line supplies the left and right rear wheel controllers. This localized power distribution ensures that when one power line fails, only the specific wheels dependent on that line are affected, while other wheels maintain full braking capability.
2Duration of action of stationary object
If backup braking with remaining power apparatus is performed when abnormality occurs, then system continuity is maintained, but minimum required deceleration cannot be satisfied
Solution Approach 1:
The system performs preliminary detection of power line abnormalities through voltage detection units that continuously monitor each power line. When an abnormality is detected, the control unit immediately identifies which specific wheel controllers are affected and pre-calculates the emergency braking force distribution, enabling rapid response that maintains both system continuity and required deceleration performance.
Solution Approach 2:
The emergency braking force is dynamically adjusted based on the specific power line failure scenario. The control unit calculates different braking force distributions for different failure modes (first, second, or third power line failure), optimizing the braking performance to satisfy minimum required deceleration while accounting for the asymmetric impact of each power line failure on the four wheels.
Data Source
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AI summary
A power supply apparatus includes a battery and a DC-DC converter converting a voltage value of the battery; a main controller determining commands required for driving and braking of a vehicle; an auxiliary controller controlling driving and braking of the vehicle when the main controller is in a function degraded status or an unfunctional status; left front, right front, left rear and right rear wheel controllers generating a braking force using an electronic mechanical brake mounted on each wheel of the vehicle; a first power line supplying power to the main controller and the left front wheel controller from a power branch point starting from the DC-DC converter; a second power line supplying power to the auxiliary controller and the right front wheel controller from the power branch point; and a third power line supplying power to the left rear and right rear wheel controllers from the power branch point.