Vehicle Steering Control Using Wheel Torque for Steering Accuracy
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Solution Overview
Problem
Friction and inertia in the steering mechanism of electric power steering systems impair steering feeling and accuracy, leading to difficulties in correct steering and increased deformation of steering components under load.
Innovation Solution
The vehicle control device controls steering force and reaction force by adjusting braking and driving forces on each wheel, improving apparent rigidity and steering accuracy through independent control of braking forces on four wheels and consideration of lateral forces and steering angular acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a motor and deceleration mechanism are added to electric power steering to provide boosting and assisting functions, then energy saving and active steering control are improved, but friction and inertia increase leading to reduced controllability and unnatural steering feeling
Solution Approach 1:
The patent replaces the mechanical deceleration mechanism with an electrical control system using motor torque control. The motor controller adjusts torque based on steering angular acceleration detection, eliminating the need for mechanical gears and reducing friction and inertia effects while maintaining steering assistance functionality.
Solution Approach 2:
The patent changes the control parameter from static torque control to dynamic torque control based on steering angular acceleration. By detecting steering angular acceleration and adjusting motor torque accordingly, the system adapts to varying steering conditions, improving steering feeling and controllability.
2Volume of moving object
If the steering mechanism uses a column electric power steering design, then compact structure is achieved, but apparent rigidity decreases and mounting portion deformation increases under steering load
Solution Approach 1:
The patent implements feedback control by detecting steering angular acceleration and using this information to adjust motor torque output. This feedback mechanism compensates for the reduced rigidity in column electric power steering designs, maintaining steering accuracy and reducing mounting portion deformation through active torque adjustment.
Solution Approach 2:
The patent applies preliminary action by proactively adjusting motor torque based on detected steering angular acceleration before significant deformation occurs. The controller anticipates loading conditions and pre-adjusts torque to compensate for potential mounting portion deformation, maintaining steering precision.
3Ease of operation
If friction and inertia in the steering mechanism are reduced through weight reduction and responsiveness improvement, then steering feeling and controllability are enhanced, but manufacturing cost increases
Solution Approach 1:
The patent replaces mechanical solutions (weight reduction, friction reduction through expensive materials) with an electrical control solution. By using motor torque control based on steering angular acceleration detection, the system achieves enhanced steering controllability without requiring costly mechanical modifications or premium materials.
Data Source
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AI summary
The present invention provides a vehicle control device and method capable of ensuring steering accuracy. In a vehicle provided with a left-right pair of steered wheels for which the braking/driving forces can each be controlled, and a steering force generation device that generates steering force for the steered wheels and controls the steering angle of the steered wheels, this vehicle control device and method control the steering force and the steering reaction force from the steering force generation device by controlling the braking/driving force of each of the steered wheels on the basis of the lateral force acting on the steered wheels.