Clutch Actuator Control Using Position and Force Feedback
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Solution Overview
Problem
Electric drives with multi-speed transmissions require significant structural effort for clutches and actuators, and are prone to switching inaccuracies due to manufacturing tolerances and wear over the vehicle's lifespan, leading to reliability issues.
Innovation Solution
A method and actuation arrangement that senses both position and force signals to calibrate the actuator drive, allowing for precise control of the clutch unit, compensating for changes in component positions and tolerances, and adjusting the shifting process to minimize wear and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-speed transmissions with clutch shifting are used, then transmission functionality is improved, but structural complexity and manufacturing effort increase significantly
Solution Approach 1:
The actuator is designed to perform multiple functions: it actuates the clutch for gear shifting, positions the shift fork, and enables neutral positioning. This multi-functionality reduces the need for separate actuators for each function, thereby reducing overall structural complexity while maintaining transmission functionality.
Solution Approach 2:
The actuating element is integrated within the existing transmission structure, with the shift fork nested within the clutch assembly. This nesting approach allows the actuator to control multiple components (clutch plates, shift fork) through a single integrated mechanism, reducing the number of separate parts and assembly steps.
2Force
If high shifting forces are required for multi-speed transmissions with synchronizing units, then shifting capability is improved, but actuator demands and complexity increase
Solution Approach 1:
The actuator system incorporates dynamic control through electronic control unit that adjusts actuation forces based on real-time feedback from position sensors. This allows the system to apply high forces only when necessary during shifting operations, while using lower forces during positioning and idle states, reducing overall actuator complexity and power requirements.
Solution Approach 2:
Position sensors provide continuous feedback on the actuating element's position, enabling the control system to modulate actuator output forces dynamically. This feedback mechanism ensures high shifting forces are applied precisely when needed to overcome synchronizer resistance, while preventing excessive force application that would require oversized actuators.
3Device complexity
If conventional actuation systems are used without compensation for tolerances and wear, then device simplicity is maintained, but switching accuracy deteriorates over service life
Solution Approach 1:
Position sensors continuously monitor the actuating element's position and provide feedback to the control unit. This feedback enables the system to detect position deviations caused by manufacturing tolerances and wear, and automatically compensate by adjusting actuator output to maintain precise switching accuracy throughout the service life.
Solution Approach 2:
The control system dynamically adjusts actuation parameters (position commands, force levels, timing) based on sensor feedback and stored characteristic curves. This parameter adaptation allows the system to compensate for changes in component dimensions due to wear and manufacturing variations, maintaining switching precision without increasing mechanical complexity.
4Measurement precision
If characteristic curves for position-dependent and force-dependent control are used, then control precision is improved, but device complexity and switching logic increase
Solution Approach 1:
The control unit uses sensor feedback to determine which characteristic curve to apply and to interpolate between curves in real-time. This feedback-driven curve selection and interpolation simplifies the control logic compared to mechanical switching mechanisms, as the electronic control can smoothly transition between different control modes based on actual position and force conditions.
Solution Approach 2:
The system stores multiple characteristic curves in memory and dynamically selects and interpolates between them based on operating conditions. This parameter-based approach allows high control precision across different operating ranges (position-dependent and force-dependent) without requiring complex mechanical switching hardware, as the curve transitions are handled electronically.
Data Source
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AI summary
The invention relates to a method for controlling an actuating assembly for a clutch in the drive train of a motor vehicle, wherein the actuating assembly has a drive (46) for displacing an actuating element (45) in order to actuate a clutch unit (12), wherein the method comprises the following steps: sensing a position signal representing the position P of the actuating element (45); sensing a force signal representing the actuating force F for displacing the actuating element (45); controlling the drive (46) by means of an electronic control unit depending on the position signal and the force signal. The invention further relates to an actuating assembly for carrying out the method and also a drive assembly having an actuating assembly of this type.