Steer-by-Wire End-Stop Breakdown Detection From Angle and Torque
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Solution Overview
Problem
Steer-by-wire systems face limitations in steering wheel rotation due to mechanical and software end stops, leading to potential breakdowns and instability, which can cause accidents if not detected promptly.
Innovation Solution
An apparatus and method for detecting mechanical end stop (MES) breakdowns in steer-by-wire systems using sensing information such as steering wheel angle, disturbance torque, and curb detection to enhance steering stability and prevent accidents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical end stop (MES) is used to enforce mechanical rotation restriction of steering wheel, then steering wheel rotation is limited to prevent over-rotation, but MES may break down due to assembly abnormality or hardware failure leading to steering instability
Solution Approach 1:
The system continuously monitors steering wheel angle and disturbance torque in real-time, comparing actual values against expected ranges. When deviations indicate MES breakdown, the system provides feedback to alert the driver and adjust control parameters, resolving the contradiction by detecting reliability issues before they cause harmful effects
Solution Approach 2:
The patent introduces an intermediary detection system between the MES and the steering wheel that monitors for breakdown conditions. This intermediary layer detects assembly abnormalities or hardware failures before they lead to steering instability, allowing preventive action without compromising the MES rotation restriction function
2Ease of operation
If soft end stop (SES) is used to enforce software rotation restriction, then steering wheel can be turned beyond mechanical limits, but driver cannot feel the end stop and may generate excessive force causing damage
Solution Approach 1:
The system monitors steering wheel angle and disturbance torque continuously. When the steering wheel approaches SES limits, the system provides feedback through disturbance torque detection to alert the driver of approaching limits, preventing excessive force generation while maintaining the extended rotation range benefit
3Loss of information
If MES breakdown is not detected, then driver cannot recognize steering device failure, but steering wheel may rotate beyond safe limits causing accidents
Solution Approach 1:
The system continuously monitors steering wheel angle and disturbance torque, providing real-time feedback to detect MES breakdown conditions. When breakdown is detected through angle deviations or abnormal torque patterns, the system alerts the driver immediately, preventing accidents by maintaining driver awareness of steering device status
Solution Approach 2:
The system performs preliminary detection of MES breakdown conditions by monitoring steering wheel angle and disturbance torque before dangerous rotation occurs. By detecting assembly abnormalities or hardware failures early through continuous monitoring, the system takes preliminary action to alert the driver and prevent accidents
Data Source
AI summary
Disclosed are an apparatus for steering by wire and an operating method thereof which detect whether mechanical end stop (MES) enforcing mechanical rotation restriction of a steering wheel has a breakdown based on sensing information of the apparatus for steering by wire to enhance steering stability and prevent an accident due to steering instability.