Steering Actuator Jerk Monitoring for Belt Jump Detection

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Solution Overview

Problem

Existing methods for monitoring steering systems, particularly in autonomous vehicles or steer-by-wire systems, face challenges in accurately detecting belt jumps and loss of traction/torque due to system stiffness and interference from manual torque applications.

Innovation Solution

The method involves determining and evaluating a jerk signal from the operating signal of the steering actuator to detect changes and determine frictional connections or torque breaks in the steering system, thereby improving detection efficiency and operational reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If belt jump detection is performed by evaluating manual torque applied to the steering wheel, then detection capability is provided, but detection accuracy deteriorates due to system stiffness and distortion from manual torque applications

Engineering Contradiction:
Improvedetection capabilityVSAvoiddetection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent extracts the harmful influence of manual torque by introducing a compensation value that is subtracted from the measured torque signal. This separation allows the detection algorithm to work with a corrected torque value that reflects actual belt jump conditions rather than being distorted by normal steering operations.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the evaluation parameter from raw manual torque to a corrected torque value that accounts for system stiffness. By adjusting the parameter being monitored (torque minus compensation value), the system achieves accurate detection without being affected by the inherent stiffness of the steering system.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If monitoring methods are designed for conventional steering systems, then detection efficiency is achieved, but adaptability deteriorates for autonomous vehicles and steer-by-wire systems

Engineering Contradiction:
Improvedetection efficiencyVSAvoidsystem compatibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal monitoring method that can be applied to multiple steering system types including conventional systems, autonomous vehicles, and steer-by-wire systems. The method uses operating signals from the steering actuator that are common across different system architectures, enabling one solution to serve multiple functions and applications.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent transitions from mechanical torque sensing to electronic operating signal evaluation. By using electrical/ electronic signals from the steering actuator rather than purely mechanical torque measurement, the system becomes adaptable to both traditional mechanical steering systems and modern electronic/steer-by-wire systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If comprehensive monitoring of steering system operation is implemented, then operational reliability is improved, but device complexity increases

Engineering Contradiction:
Improveoperational reliabilityVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent enables the steering actuator to serve dual functions: both steering control and self-monitoring for belt jump detection. By utilizing operating signals already generated during normal actuator operation, the system achieves comprehensive monitoring without adding separate dedicated sensing components, thus maintaining reliability while limiting complexity increase.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4380844B1Method for monitoring a steering system
Publication Date: 2025.06.04 ROBERT BOSCH GMBH
  • EP4380844B1 patent drawingFigure 1a~1b
  • EP4380844B1 patent drawingFigure 2
  • EP4380844B1 patent drawingFigure 3

AI summary

The invention relates to a method for monitoring a steering system (10), more particularly during the operation in a vehicle (12), wherein the steering system (10) comprises at least one steering actuator (14), and wherein, in order to determine a force-closure detachment and/or torque detachment in the steering system (10), at least one operating signal (16) of the steering actuator (14) is determined and evaluated. It is proposed that, in order to determine a force-closure detachment and/or torque detachment in the steering system (10), a jerk signal (18) is determined from the operating signal (16) and is monitored for changes.