Friction Clutch Chatter Vibration Compensation
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Solution Overview
Problem
Automated friction clutches in vehicle drivetrains experience chatter vibrations due to geometric flaws, leading to discomfort and increased wear, with existing methods struggling to effectively compensate for multiple frequency components and phase jumps.
Innovation Solution
A method that calculates necessary actuation corrections in the clutch system using Fourier analysis of input signals like transmission input speed or vehicle acceleration, allowing for phase-selective correction of target clutch torque to reduce chatter vibrations, with optional support from an electric motor in hybrid vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If automated friction clutches are used to replace manual clutch operation, then clutch operation precision and consistency are improved, but chatter vibrations occur due to geometric flaws causing discomfort and increased wear
Solution Approach 1:
The patent applies vibration counteraction by generating a compensation signal with specific amplitude and phase characteristics that opposes the chatter vibrations. The compensation torque is calculated based on the detected vibration parameters and applied through the clutch actuator to cancel out the harmful vibrations caused by geometric flaws in the friction clutch components.
Solution Approach 2:
The system continuously monitors the clutch operation and detects chatter vibrations in real-time. The detected vibration parameters (amplitude, phase, frequency) are fed back to the control unit, which dynamically adjusts the compensation torque to counteract the vibrations. This closed-loop feedback mechanism ensures that the compensation adapts to changing vibration conditions while maintaining precise clutch operation.
2Object-affected harmful factors
If existing vibration compensation methods are applied, then single-frequency vibrations can be reduced, but multiple frequency components and phase jumps cause the compensation to become difficult to track and less effective
Solution Approach 1:
The patent implements a dynamic compensation approach where the compensation parameters (amplitude, phase, frequency) are continuously updated based on real-time detection of vibration characteristics. The system adapts to multiple frequency components by detecting and tracking each frequency component separately and generating corresponding compensation signals. Phase jumps are handled by continuously monitoring phase changes and adjusting the compensation signal accordingly, making the system versatile and effective for complex vibration patterns.
3Measurement precision
If the actuation path is adjusted to achieve target clutch torque, then clutch torque control is improved, but geometric properties and manufacturing tolerances cause uneven frictional engagement and chatter vibrations
Solution Approach 1:
The patent introduces a compensation torque as an intermediary control element that mediates between the target clutch torque and the actual clutch torque. The compensation torque counteracts the uneven frictional engagement caused by geometric imperfections and manufacturing tolerances. By adding this intermediary compensation component, the system achieves precise clutch torque control despite the inherent geometric flaws in the friction clutch components.
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
This method effectively reduces chatter vibrations by stabilizing the control signal and compensating for geometric flaws, even in complex vibration patterns, using a combination of amplitude and phase corrections, and can be implemented in existing control units.
Implementation Method 1
an absolute amplitude and a phase of an input signal are obtained from an input signal which is representative of the clutch torque marked by vibrations, on the basis of a vibration-selective guidance variable derived in a torque pattern between the internal combustion engine and the friction clutch
Data Source
AI summary
A method for reducing chatter vibrations of a friction clutch controlled automatically by a clutch actuator on the basis of a target clutch torque assigned to a clutch torque which is to be transmitted. The clutch has a present actual clutch torque which is marked by vibrations as a result of chatter vibrations which occur occasionally. In order to achieve a reduction of the chatter vibrations, from an input signal that is representative of the clutch torque that is marked by vibrations, on the basis of a vibration-selective guidance variable derived in a torque pattern between internal combustion engine and friction clutch, an absolute amplitude and a phase of the input signal are ascertained on the basis of a transfer function which maps the guidance variable on a vibration-selective clutch torque; from that a correction clutch torque is determined; and using that the target clutch torque is corrected.