Steering Control Readiness Sensing for Fault-Based Speed Limits
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Solution Overview
Problem
Existing steering systems in motor vehicles, particularly steer-by-wire systems without mechanical fallbacks, face safety risks due to altered steering characteristics and impaired maneuverability during malfunctions, which can negatively impact vehicle safety.
Innovation Solution
A steering system with a readiness detection unit to monitor operational readiness of actuators, determining a status class based on functional parameters, and a speed determination unit to set permissible speed values, ensuring safe vehicle operation by limiting speed based on system availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle operates with reduced actuators due to malfunction, then reliability is improved by maintaining steerability, but safety deteriorates due to altered steering characteristics and impaired maneuverability
Solution Approach 1:
The system dynamically adjusts the maximum permissible vehicle speed based on the operational status of actuators. When actuators malfunction, the control unit reduces the speed limit to compensate for impaired steering characteristics, ensuring safety is maintained while preserving steerability with reduced components
Solution Approach 2:
The system changes the operational parameter (vehicle speed) based on actuator readiness status. By determining status classes from operational readiness values and correlating them with maximum permissible speeds, the system adapts its operating conditions to match the current capability of the steering system
2Object-affected harmful factors
If the vehicle speed is limited based on actuator readiness, then safety is improved, but productivity deteriorates due to reduced operating speed
Solution Approach 1:
The system applies partial speed limitation based on the degree of actuator malfunction. Instead of completely restricting speed, it determines status classes that correlate with specific maximum permissible speeds, allowing the vehicle to operate at the highest safe speed given the current actuator configuration
Solution Approach 2:
The maximum permissible speed is dynamically adjusted based on real-time actuator readiness assessment. The system continuously monitors operational readiness values, updates status classes, and modifies speed limits accordingly, optimizing the balance between safety and productivity
Data Source
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Figure 3
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AI summary
The present invention relates to a steering system (10) for a motor vehicle, comprising a plurality of actuators (15, 17, 18, 22, 21, 27, 29, 400, 401, 402), operatively connected in each case to at least one wheel (13, 25), and a steering-control unit (12), which is connected to said actuators and has an input unit and an output unit and is designed and set up to activate the actuators (15, 17, 18, 22, 21, 27, 29, 400, 401, 402) in such a way that the motor vehicle is guided on a specified track path on the basis of input signals entered into the input unit, wherein, to increase the fail safety, it is proposed that the steering-control unit (12, 121) has a readiness-sensing unit (5) and a speed-determining unit (6), wherein the readiness-sensing unit (5) is designed and set up for sensing operational-readiness values of the actuators (15, 17, 18, 22, 21, 27, 29, 400, 401, 402) and the speed-determining unit (6) is designed and set up to determine from the sensed operational-readiness values permissible speed values (v0, v1, v2, v3, v4, v5, vy1, vy2) of the track speed of the motor vehicle.