Electromechanical Wheel Brake Force Control Without Extra Sensors
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Solution Overview
Problem
Existing electromechanical wheel brakes face inaccuracies in adjusting forces due to deviations in the relationship between application force and travel, often requiring additional sensors which occupy space and complicate the mechanical design.
Innovation Solution
A method for controlling the actuator of an electromechanical wheel brake that determines setpoint positions and corrects for offsets using actuator signals, eliminating the need for additional sensors by utilizing initialization functions and characteristic curves to adjust forces accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If force sensors or braking torque sensors are used for each brake unit to adjust application forces with required accuracy, then manufacturing precision and reliability are improved, but device complexity and space requirements increase
Solution Approach 1:
The patent extracts the force measurement function from separate physical sensors and relocates it to the actuator's control unit. The control unit calculates application forces based on actuator position data from existing position sensors and stored characteristic curves, eliminating the need for separate force sensors at each brake unit.
Solution Approach 2:
The patent introduces characteristic curves as an intermediary element that mediates between actuator position and application force. These curves, stored in the control unit, translate position measurements into force values without requiring direct force measurement, thus resolving the contradiction between accuracy and complexity.
2Measurement precision
If space is allocated for integrating force sensors in the mechanical design of brake units, then measurement precision is improved, but the space available for other components is reduced
Solution Approach 1:
The patent makes the actuator's control unit multi-functional by enabling it to perform both position control and force measurement tasks. The same control unit that manages actuator position also calculates application forces using stored characteristic curves and position data, eliminating the need for additional force sensing components.
Solution Approach 2:
The force measurement capability is extracted from separate sensor hardware and integrated into the software/control algorithms of the actuator control unit. This extraction eliminates the need for additional physical sensors and their associated mounting space in the brake unit assembly.
3Reliability
If wear of brake disk or brake linings causes deviations in the relationship between application force and application travel, then reliability deteriorates, but this wear is unavoidable over time
Solution Approach 1:
The patent applies preliminary action by performing initialization functions that detect and compensate for changes in the characteristic curves due to wear. The system proactively adjusts the stored characteristic data during initialization phases (such as after assembly or maintenance) to account for wear-induced deviations, maintaining reliability throughout the component service life.
Solution Approach 2:
The patent implements feedback mechanisms where the control unit continuously monitors the relationship between actuator position and application force. When deviations are detected that indicate wear, the system uses feedback to adjust the characteristic curves and maintain accurate force control, compensating for wear effects over time.
Data Source
AI summary
The embodiments relate, in general, to a method for adjusting tensioning forces in an electromechanical wheel brake of a motor vehicle and to a motor vehicle brake having an electromechanical wheel brake designed in such a way. The method for controlling an actuator for a brake actuator of an electromechanical wheel brake, provides, inter alia, for the carrying out of an initialization function for determining a first offset position and the subsequent correction of the setpoint position of the actuator by the determined first offset position.