Vehicle Steering Angle Calculation Using Dynamic Model and LMI Optimization
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Solution Overview
Problem
Existing driving assistance systems cannot accurately calculate a humanoid steering angle to maintain a vehicle within a traffic lane, as they lack an electric power steering model and do not adequately consider safety and comfort criteria such as limited lateral speed and yaw rate derivatives.
Innovation Solution
A driving aid method and device that calculates a steering angle using a dynamic vehicle model incorporating a bicycle model, electric power steering, and lateral position integral, with safety and comfort criteria met through convex optimization under Linear Matrix Inequalities (LMI) constraints, ensuring bounded convergence and acceptable driver comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dynamic vehicle model incorporating electric power steering and convex optimization under LMI constraints is used, then the accuracy of humanoid steering angle calculation is improved, but the device complexity increases
Solution Approach 1:
The control system is segmented into distinct functional modules: a bicycle model module for basic vehicle dynamics, an electric power steering model module, and an LMI optimization module. Each module handles a specific aspect of the control problem, allowing the complex overall system to be developed, tested, and implemented in manageable parts while maintaining high calculation accuracy.
Solution Approach 2:
The patent introduces an intermediary convex optimization framework under LMI constraints that bridges the bicycle model and electric power steering model. This intermediary layer transforms the complex nonlinear control problem into a computationally tractable form, enabling accurate humanoid steering angle calculation without requiring excessive computational resources or system complexity.
2Reliability
If safety and comfort criteria such as limited lateral speed and yaw rate derivatives are strictly enforced, then driver comfort and safety are improved, but the convergence speed of lateral error to zero may be reduced
Solution Approach 1:
The control system dynamically adjusts the steering angle calculation by incorporating time-varying constraints on lateral speed and yaw rate derivatives through the LMI framework. These constraints are not fixed but adapt based on current vehicle state, allowing the system to maintain safety and comfort while optimizing convergence speed under different operating conditions.
Solution Approach 2:
The patent changes the parameters of the control system by introducing bounded convergence criteria for lateral error. Instead of pursuing unlimited fast convergence, the system optimizes for bounded convergence that respects physical constraints on lateral acceleration and yaw rate, transforming the optimization problem from unconstrained to constrained parameter space.
Data Source
Figure 1~3
AI summary
A driver assistance method for motor vehicles in which the steering angle (δref) of the vehicle's steering wheels is calculated within a traffic lane. The steering angle (δref) is calculated from a dynamic model of the vehicle and from parameters relating to vehicle behavior, while respecting safety and driver comfort criteria.