Vehicle Control Apparatus Steering Reaction Force Cancellation
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Solution Overview
Problem
Existing vehicle control systems face challenges in canceling steering reaction force during automatic steering without discomforting the driver, as they often rely on detecting actual steering torque, leading to incomplete cancellation and interference with driver inputs.
Innovation Solution
A control apparatus that uses a braking/driving force varying device to set target braking/driving forces for each wheel, managing steering reaction force through relative relations between vehicle state quantities and steering reaction force, allowing for precise control of front and rear wheel differences to maintain target motion states without interfering with driver inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steering reaction force is canceled by applying counter torque through motor 2, then steering reaction force cancellation is improved, but driver comfort deteriorates due to interference with intentional steering inputs
Solution Approach 1:
The system calculates and applies counter torque in advance based on predicted steering reaction force, rather than reacting to actual detected torque. By using a prediction model that estimates steering reaction force from vehicle state quantities (yaw rate, lateral acceleration, steering angle) and applying counter torque proactively, the system cancels steering reaction force before it fully manifests, preventing driver discomfort while maintaining cancellation effectiveness
Solution Approach 2:
The system uses feedback from vehicle state sensors (yaw rate sensor, lateral acceleration sensor, steering angle sensor) to continuously update the prediction model and adjust the counter torque application. The feedback loop compares predicted versus actual vehicle response and refines the counter torque calculation to achieve optimal cancellation without interfering with driver intent
2Loss of information
If steering reaction force is detected through steering torque sensor, then measurement is obtained, but detection precision deteriorates because steering reaction force is only detectable after it actualizes as steering torque
Solution Approach 1:
Instead of waiting for steering reaction force to actualize as detectable steering torque, the system performs preliminary calculation of the expected steering reaction force using a prediction model. The model computes predicted steering reaction force from current vehicle state quantities before the force fully manifests, enabling early intervention and more precise timing for counter torque application
Solution Approach 2:
The system introduces vehicle state quantities (yaw rate, lateral acceleration, steering angle) as intermediary variables to infer steering reaction force. Rather than directly measuring the difficult-to-detect steering reaction force, the system uses these readily available sensor measurements as mediators to calculate and predict the steering reaction force with higher precision and earlier timing
Data Source
AI summary
A control apparatus for controlling a vehicle which is provided with a braking/driving force varying device capable of individually changing a braking/driving force acting on each of wheels (FL, FR, RL, RR) with respect to each wheel. The control apparatus includes a target state quantity setting device for setting a target state quantity corresponding to a target motion state of the vehicle; and a target braking/driving force setting device for setting a target braking/driving force, which is a target value of the braking/driving force, such that a state quantity corresponding to the target state quantity and a steering reaction force transmitted to a steering apparatus from the wheel are the set target state quantity and a predetermined target steering reaction force, respectively, on the basis of a relative relation, which is set in advance, between the state quantity and the steering reaction force, and a left-right braking/driving force difference of front wheels and a left-right braking/driving force difference of rear wheels.