Clutch Torque Estimation via Angular Velocity Feedback
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Solution Overview
Problem
In dual-clutch transmissions (DCTs) with dry clutches, accurately estimating clutch torque is challenging due to changing clutch characteristics with temperature, wear, and deformation, affecting launch performance and shifting quality.
Innovation Solution
A clutch torque estimating method that inputs model engine torque and target clutch torques into a powertrain model, corrects the model in real-time using angular velocity errors, and estimates clutch torque for both clutches, allowing for precise control without relying on direct torque measurement sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is used to directly measure clutch torque, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces an observer as an intermediary system that indirectly estimates clutch torque by measuring angular velocities of the engine, clutch, and wheels, and processing these measurements through a powertrain model. This mediator approach avoids direct torque sensing while achieving accurate estimation through mathematical relationships and error correction mechanisms.
Solution Approach 2:
The patent replaces the mechanical torque sensor with a computational estimation system using angular velocity measurements and mathematical models. The mechanical measurement system is substituted with an electronic observation and calculation system that processes angular velocity data through differential equations and feedback loops to derive torque values.
2Adaptability or versatility
If clutch characteristics are allowed to change with temperature and wear, then adaptability is improved, but measurement precision deteriorates
Solution Approach 1:
The patent implements dynamic adaptation by continuously updating the powertrain model parameters based on real-time operating conditions including temperature and wear state. The observer adjusts clutch friction coefficients and other characteristics dynamically rather than using fixed values, allowing the system to adapt to changing conditions while maintaining estimation accuracy through continuous correction.
Solution Approach 2:
The patent employs feedback mechanisms where the observer continuously compares estimated angular velocities with actual measurements, calculates errors, and uses these errors to correct the powertrain model parameters in real-time. This feedback loop ensures that even as clutch characteristics change due to temperature and wear, the system compensates by adjusting its model parameters to maintain accurate torque estimation.
3Measurement precision
If a Torque-Stroke (T-S) curve map is used to control clutch torque, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent enables the control system to self-adjust by using the observer's torque estimates to automatically update the powertrain model and control parameters without requiring external calibration or manual intervention. The system serves itself by continuously learning from measurement errors and adapting its internal model, eliminating the need for complex pre-programmed T-S curve maps while maintaining high control precision.
Data Source
AI summary
A clutch torque estimating method for a transmission of a vehicle may include inputting model engine torque to a powertrain model by a controller; inputting target clutch torque of a first clutch and target clutch torque of a second clutch to the powertrain model by the controller; inputting shifting information related to the vehicle to the powertrain model by the controller; correcting the powertrain model in real time by feeding back an engine angular velocity error, a clutch angular velocity error of the first clutch, a clutch angular velocity error of the second clutch, a wheel angular velocity error to the powertrain model by the controller; and estimating clutch torque of the first clutch and clutch torque of the second clutch by determining the powertrain model by the controller.