Vehicle Steering Control Device Reactive Force Adjustment
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Solution Overview
Problem
Industrial vehicle steering control devices lack the ability to effectively impart a steering reactive force to the steering wheel, leading to inconsistent steering feel and increased instability, especially for operators unfamiliar with high-speed driving.
Innovation Solution
A vehicle steering control device that calculates a command steering reactive force based on detected wheel angles and vehicle state parameters, using correction coefficients to adjust the steering reactive force imparted to the steering wheel, including features like intermittent force settings for anomaly detection and neutral state recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an all-electric steering control device is used without mechanical coupling between steering wheel and steered wheels, then the steering system can be simplified and controlled electrically, but the reactive force cannot be transmitted from steered wheels to steering wheel, resulting in constant steering force regardless of vehicle state
Solution Approach 1:
The patent replaces the mechanical coupling system with an electric control system using a brake device to generate reactive force. Instead of mechanical transmission from steered wheels to steering wheel, an electric motor-driven brake applies controlled friction to the steering wheel's rotary shaft, substituting mechanical reactive force transmission with electrically-controlled friction braking.
Solution Approach 2:
The patent changes the steering force parameter dynamically based on vehicle state (speed, acceleration, steering angle). The brake control unit adjusts the brake force magnitude according to detected vehicle parameters, transforming the constant steering force into a variable steering force that adapts to different operating conditions, improving steering feel and stability.
2Ease of operation
If a brake device is added to impart steering reactive force to the steering wheel, then the steering feeling is improved, but the device complexity increases
Solution Approach 1:
The brake device serves multiple functions: it generates steering reactive force to improve steering feeling, provides vehicle speed-dependent force adjustment, and integrates with the existing electric motor control system. The brake actuator is controlled by the same control unit that manages the electric motor, allowing the brake system to perform steering assistance while sharing control infrastructure.
Solution Approach 2:
The brake device acts as an intermediary between the electric motor control system and the steering wheel. Instead of directly coupling the electric motor to the steering wheel, the brake provides a mediated reactive force through controlled friction on the rotary shaft, allowing independent control of steering actuation and reactive force generation.
3Reliability
If the steering reactive force is made variable according to vehicle speed and state, then the steering stability at high speed is improved, but the control system complexity increases
Solution Approach 1:
The system uses feedback from vehicle state sensors (speed sensor, acceleration sensor, steering angle sensor) to continuously adjust the brake force. The control unit receives real-time data about vehicle operation and dynamically modifies the reactive force magnitude, creating a closed-loop control system that automatically adapts to changing conditions without requiring complex manual intervention.
Solution Approach 2:
The steering reactive force transitions from a static constant value to a dynamic variable that changes with vehicle state. The brake control system continuously adjusts the friction force based on real-time vehicle parameters, making the steering system adaptive and responsive to different operating conditions such as speed changes, acceleration, and steering angle variations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves steering feel by considering both wheel angle and vehicle state parameters, enhances operator awareness of vehicle anomalies, and prevents accidents by clearly indicating neutral states, providing a more intuitive control experience.
Implementation Method 1
a pinion 8 fixed on a rotary shaft of the electric motor 7; a rack 9 meshing with the pinion 8
Implementation Method 2
capable of imparting a steering reactive force to the steering wheel 2 by exerting an electric brake force on the rotary shaft
Data Source
AI summary
A steering control device obtains a command steering reactive force according to a wheel angle based on a wheel angle and table data representing the correlation between the wheel angle and the command steering reactive force, and which controls an electric-control brake to make the steering reactive force equal to the command steering reactive force. The steering control device: obtains a correction coefficient according to vehicle state amounts based on the vehicle state amounts other than the wheel angle, which are detected by vehicle state amount detecting means, and table data representing the correlation between the vehicle state amounts and the correction coefficients; corrects the table data by using the correction coefficients; obtains a command steering reactive force according to the wheel angle based on the table data and the wheel angle; and controls the electric-control brake to make the steering reactive force equal to the command steering reactive force.