Torque Estimation for Steering Assist Using Eccentric Mass Analysis
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Solution Overview
Problem
Conventional steering systems face challenges in accurately estimating the steering intention of a driver, particularly due to the lack of consideration for eccentric torque generated by the eccentricity of the steering wheel, which affects the accuracy of steering control.
Innovation Solution
A torque estimation apparatus and method that calculates the standard deviation of driver torques to estimate the eccentric mass and torque of the steering wheel, using a steering angle sensor to refine the steering motor control signal and improve steering assist functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional steering systems estimate driver torque without considering eccentric torque, then the steering control system is simpler, but the accuracy of steering intention estimation deteriorates
Solution Approach 1:
The torque estimation is segmented into two distinct components: driver torque and eccentric torque. The first estimator calculates driver torque based on steering torque sensor data, while the second estimator calculates eccentric torque based on steering angle sensor data and detected eccentric mass. This segmentation allows each estimator to focus on specific torque components, improving overall estimation accuracy without requiring a complete system redesign.
Solution Approach 2:
A torque synthesis unit acts as an intermediary that combines the outputs of the first estimator (driver torque) and the second estimator (eccentric torque) to produce the total steering torque. This intermediary component integrates the separate torque estimations in a coordinated manner, allowing the system to benefit from both estimates without direct complex interaction between the estimators.
2Measurement precision
If the system calculates standard deviation of driver torques to estimate eccentric mass, then the eccentric torque estimation accuracy improves, but the calculation complexity increases
Solution Approach 1:
The system performs preliminary calculation of the standard deviation of driver torques before estimating the eccentric mass. By pre-calculating the standard deviation from historical torque data, the system establishes a statistical baseline that informs the eccentric mass estimation, improving accuracy without requiring complex real-time calculations during steering operation.
Solution Approach 2:
The torque synthesis unit feeds back the total steering torque to the first estimator, creating a closed-loop system. This feedback mechanism allows the estimators to continuously refine their calculations based on actual system performance, improving estimation accuracy over time while maintaining a manageable calculation complexity through iterative refinement rather than complex one-time calculations.
Data Source
AI summary
The present invention relates to steering apparatuses, and more specifically, to torque estimation apparatuses, and steering assist apparatuses and methods. The torque estimation apparatus can include a first estimator for estimating an eccentric mass of a steering wheel, and a second estimator for estimating an eccentric torque of the steering wheel.