Steering Torque Estimation Using Corrected Lateral Force Models
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Solution Overview
Problem
Current Advanced Driver Assistant Systems (ADAS) and autonomous driving systems face challenges in accurately estimating steering torque for lateral vehicle control, often resulting in excessive torque that compromises safety and comfort, and require driver intervention, as they rely solely on steering angle inputs without considering varying driving conditions.
Innovation Solution
A method and device that estimate steering torque by detecting vehicle and environmental signals, using tire and lateral dynamics models to correct lateral force values, and calculating self-aligning torque, allowing for accurate torque estimation with limited computational effort, incorporating sensors like GPS, IMU, cameras, and radar for input data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If maximum steering torque is applied to reach desired steering angle, then steering response speed is improved, but driving comfort and safety deteriorate due to excessive torque exceeding permissible limits
Solution Approach 1:
The system performs preliminary estimation of steering torque requirements based on detected driving conditions (vehicle speed, steering angle, road curvature) before actual steering execution. This allows the control system to pre-calculate appropriate torque levels that achieve desired steering angles without exceeding permissible limits, thereby maintaining both fast response and driver comfort
Solution Approach 2:
The steering torque is dynamically adjusted based on real-time driving conditions. The control system continuously monitors vehicle speed, steering angle, and road curvature to adaptively modify torque application, ensuring optimal steering response at different operating points while preventing excessive torque that would compromise comfort or safety
2Device complexity
If steering angle is used as the only input signal, then system complexity is reduced, but steering torque estimation accuracy deteriorates due to inability to account for varying driving conditions
Solution Approach 1:
The control system utilizes a multi-functional approach by processing multiple input signals (vehicle speed, steering angle, road curvature) through a unified steering torque estimation algorithm. This allows the system to accurately account for varying driving conditions while maintaining manageable complexity through integrated control logic that handles multiple parameters simultaneously
3Ease of operation
If inappropriate steering torque is applied to reach desired steering angle, then steering control simplicity is maintained, but vehicle grip and handling properties deteriorate
Solution Approach 1:
The system implements feedback control by continuously monitoring driving conditions and adjusting steering torque application accordingly. The control algorithm uses detected parameters (vehicle speed, steering angle, road curvature) to provide real-time feedback on appropriate torque levels, ensuring that steering actions maintain optimal vehicle grip and handling properties while keeping the control system relatively simple
Data Source
AI summary
Method for estimating a steering torque, in particular for the lateral control of a vehicle, comprising the steps of detecting at least one signal on a current vehicle state and/or current vehicle environment, determining a desired steering angle by a steering control unit based on the at least one detected signal, estimating a vehicle lateral force on the basis of a tire dynamics model, including the determined steering angle as an input factor, estimating a vehicle lateral force on the basis of a lateral dynamics model, correcting the lateral force value estimated by the tire dynamics model on the basis of the lateral force value estimated by the lateral dynamics model, estimating a self-aligning torque based on the corrected lateral force value, and estimating a steering torque from the estimated self-aligning torque.