Cyber-Physical System Co-Design for Watermarking and Control
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Solution Overview
Problem
Cyber-physical systems face performance degradation due to the incorporation of watermarking signals, which are used for anomaly detection, as they are injected as added noise, leading to ineffective detection rates and operational disruptions.
Innovation Solution
An integrated design architecture co-designs the controller and watermarking signal, allowing for joint development to maintain target performance levels while enhancing detection rates, using techniques like Kalman filters and chi-square detectors to mitigate replay attacks without degrading system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If watermarking signals are incorporated into the cyber-physical system for anomaly detection, then detection capability is improved, but system performance degrades due to added noise
Solution Approach 1:
The patent merges the controller design and watermarking signal design into a unified co-design framework. The controller and watermarking signal are optimized simultaneously rather than separately, allowing the system to achieve both high detection capability and maintained performance by jointly optimizing their interaction
Solution Approach 2:
The patent changes the parameters of both the controller and watermarking signal through iterative optimization. By adjusting controller parameters and watermarking signal parameters together and evaluating their combined effect on system performance and detection rate, the system finds optimal parameter settings that resolve the contradiction
2Measurement precision
If watermarking signals are enhanced to improve detection rate, then anomaly detection is improved, but performance loss increases
Solution Approach 1:
The patent implements a feedback mechanism where the system evaluates the combined effect of controller and watermarking signal parameters on both detection rate and performance. This feedback loop allows iterative refinement, adjusting parameters to achieve high detection rates while minimizing performance loss through continuous evaluation and adjustment
3Reliability
If co-design of controller and watermarking signal is performed, then detection rate is enhanced, but design complexity increases
Solution Approach 1:
The patent employs a dynamic iterative optimization process for co-design. Rather than requiring complex simultaneous optimization, the system iteratively adjusts controller and watermarking parameters, evaluating performance at each step until convergence is achieved, making the complex design process more manageable and systematic
Data Source
AI summary
Embodiments described herein provide a design architecture for co-designing a controller and a watermarking signal for a cyber-physical system. During operation, the architecture can determine, in conjunction with each other, respective values of a first set of parameters indicating operations of the controller and a second set of parameters representing the watermarking signal. Here, the watermarking signal is combinable with a control signal from the controller for monitoring an output signal of the cyber-physical system for detecting malicious data at different time instances. Subsequently, the architecture can determine a state manager for determining the states of the cyber-physical system from the monitored output signal based on the first and second sets of parameters. The architecture can also determine a detector capable of identifying presence of an attack from the states of the cyber-physical system at a plurality of time instances using the watermarking signal.