Rotary Encoder Plausibility Check via Inertial Sensor Cross-Verification
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Solution Overview
Problem
Existing devices for checking the plausibility of movement-dependent variables in motor vehicles, such as tachographs, face challenges in ensuring reliability and protection against manipulation, particularly in the recording and storage of data related to driving, working, and rest times.
Innovation Solution
A device that compares inertial sensor signals with both analog and digital signals, utilizing cryptographic encryption and a position determination system, to detect manipulations in rotary encoders and electrical connections, ensuring high safety standards through redundant information and secure data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotary encoder is used to detect movement-dependent variables, then measurement precision is improved, but reliability deteriorates due to vulnerability to manipulation and signal interference
Solution Approach 1:
An inertial sensor is introduced as an intermediary device to detect movement-dependent variables independently of the rotary encoder. The evaluation circuit compares signals from the inertial sensor with signals from the rotary encoder to detect manipulations or signal interference, thereby maintaining measurement precision while improving reliability through cross-verification
Solution Approach 2:
The system implements feedback by continuously comparing the inertial sensor signal with the rotary encoder signal. When discrepancies are detected, the system can trigger alerts or corrective actions, creating a closed-loop verification mechanism that enhances protection against manipulation while preserving measurement accuracy
2Reliability
If redundant signal comparison systems are implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The evaluation circuit merges the signal processing functions by combining the inertial sensor signal processing and rotary encoder signal processing into a single integrated unit. This allows redundant comparison to improve reliability while minimizing the increase in device complexity through functional integration
Solution Approach 2:
The evaluation circuit performs multiple functions: it processes signals from both the inertial sensor and rotary encoder, compares the signals for consistency, and detects manipulations. This multi-functionality reduces the need for separate dedicated circuits for each task, thereby improving reliability without proportionally increasing device complexity
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 effectively detects and prevents manipulations, providing a high safety standard for data integrity and accuracy in movement-dependent variable recording, enhancing the reliability of tachograph data storage and processing.
Implementation Method 1
the inertial sensor is a sensor for measuring an acceleration
Implementation Method 2
the inertial sensor is a gyroscope
Data Source
Figure 1
AI summary
A device (10) for checking the plausibility of a value of a movement-dependent variable, the device having a rotary encoder (30) for detecting the value of the movement-dependent variable, wherein said rotary encoder (30) is implemented to output an analog real-time signal (32) and a digital signal (34), which is implemented as a reference of the analog real-time signal (32), a signal detection and analysis unit (12), which is electrically coupled to the rotary encoder (30) and is implemented to record the analog real-time signal (32) and the digital signal (34), wherein said rotary encoder (30) is disposed outside said signal detection and analysis unit (12), wherein an inertial sensor (20) is disposed inside said signal detection and analysis unit (12), the sensor being implemented to output an inertial sensor signal (24), and the signal detection and analysis unit (12) being implemented to compare the inertial sensor signal (24) to the digital signal (34).