SBW Steering Wheel Reaction Force to Prevent Ignition-Off Turning
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Solution Overview
Problem
Conventional Steer-By-Wire (SBW) systems lack a mechanical or electrical load on the steering wheel and column structure, causing the steering wheel to turn easily when the ignition is off, potentially leading to accidental movement and safety issues when drivers enter or exit the vehicle.
Innovation Solution
A steering wheel control apparatus and method that generates a wake-up signal when the ignition is off, using a motor driver to create a steering reaction force against the steering wheel, preventing it from turning by shorting phases of the motor to generate counter electromotive force, thus maintaining control until the ignition is turned on or the vehicle is secured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the ignition switch is turned off, then power consumption is reduced, but the steering wheel becomes easily turnable without mechanical/electrical load
Solution Approach 1:
The system performs preliminary action by generating a wake-up signal before the ignition is fully turned off, activating the steering wheel controller to maintain control authority. This allows the system to transition from a high-power state to a low-power state while ensuring steering stability is maintained during the transition period.
Solution Approach 2:
The patent replaces the traditional mechanical connection between the steering wheel and road wheels with an electrical control system. The steering wheel controller generates control signals to the road wheel actuator, substituting mechanical load with electrical control signals that maintain steering stability without continuous power consumption.
2Reliability
If the steering wheel controller is activated continuously, then steering control is maintained, but power consumption increases
Solution Approach 1:
The system uses periodic action by activating the steering wheel controller only when needed (upon wake-up signal) rather than continuously. The controller operates in a sleep mode during normal conditions and activates periodically when the ignition state changes or when steering input is detected, reducing power consumption while maintaining control reliability.
Solution Approach 2:
The system dynamically adjusts its operational state based on ignition status and steering input. The steering wheel controller transitions between active and sleep states, and the road wheel actuator adjusts its responsiveness dynamically, allowing the system to maintain control authority only when necessary rather than operating at full capacity continuously.
3Reliability
If the steering wheel is made heavy through mechanical connection, then accidental turns are prevented, but ease of operation decreases
Solution Approach 1:
The patent replaces mechanical connection with electrical control, eliminating the need for mechanical weight to prevent accidental turns. The electronic control system detects steering input and generates appropriate control signals, providing virtual feedback that prevents accidental turns without adding physical weight to the steering wheel.
Solution Approach 2:
The steering wheel controller acts as an intermediary between the driver's steering input and the road wheel actuator. It processes steering signals and generates control commands, providing a buffer that prevents direct mechanical coupling while maintaining control authority and preventing accidental turns through electronic intervention.
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
Prevents unintended steering wheel movement when drivers get in or out of the vehicle, enhancing safety and user satisfaction by maintaining control and stability until the ignition is turned on or the vehicle is secured.
Implementation Method 1
shorting phases of the motor to generate counter electromotive force
Data Source
AI summary
A steering wheel control apparatus of an SBW (Steer-By-Wire) system may include a dominant controller configured to generate a wake-up signal, in response to an ignition switch of a vehicle being off, a motor driver configured to generate a steering reaction force against a steering wheel through a motor, and a steering wheel controller configured to generate the steering reaction force to interrupt a turn of the steering wheel, by controlling the motor driver according to the wake-up signal.