Brake System Diagnosis Using Drive Torque and Force Sensing
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Solution Overview
Problem
Brake systems with wheel-specific braking torque indication, such as electric braking systems, pose challenges in diagnosing and calibrating their functionality, especially when stationary, as the absence of braking torque on a level surface makes traditional measurement methods ineffective.
Innovation Solution
A method involving locking the wheel using the brake unit, generating a drive torque, and measuring the supporting force using a force sensor, allowing for diagnosis and calibration by adjusting control parameters like the coefficient of friction and sensor profiles, which can be done automatically and without user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wheel locking is performed to enable brake diagnosis, then measurement capability is improved, but the vehicle cannot move during diagnosis
Solution Approach 1:
The brake diagnosis is performed during an initial phase before vehicle operation. The control unit executes the diagnostic routine that locks the wheel and measures brake characteristics, storing the results for later use during actual vehicle operation. This allows the diagnosis to be completed before mobility is required.
2Measurement precision
If drive torque is generated during stationary diagnosis, then brake torque measurement is enabled, but the vehicle remains stationary
Solution Approach 1:
The drive torque generation for brake measurement is executed as a preliminary action during the stationary diagnostic phase. The control unit commands the drive train to generate the necessary torque to rotate the wheels, measures the brake resistance, and completes the diagnosis before the vehicle needs to move for normal operation.
3Duration of action of stationary object
If maintenance intervals are extended for electric braking systems, then customer benefit and environmental impact are improved, but reliability verification becomes more challenging
Solution Approach 1:
The brake system performs self-diagnosis through the control unit executing automated measurement routines. The system uses the drive train to generate test torques, measures brake characteristics during wheel locking, and automatically evaluates results against predefined thresholds. This self-service capability ensures reliability verification can be performed during regular maintenance intervals without requiring external testing equipment or complex procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable and automatic diagnosis and calibration of brake systems, ensuring safe operation and extending maintenance intervals, reducing costs and environmental impact by eliminating the need for brake fluid.
Implementation Method 1
measuring the supporting force of the brake unit on the vehicle body
Implementation Method 2
applying a brake pad to a brake element coupled to the wheel
Data Source
Figure 1
Figure 2~4
AI summary
Method for diagnosing a brake system (4) of a motor vehicle (2), comprising the following steps: diagnosing the brake unit (6) by locking the wheel (8) using the brake unit (6), generating a drive torque using a drive train (22, 24, 26) of the motor vehicle (2) and measuring the support force of the brake unit (6) as a result of the drive torque.