Neural Network Verification for Temporal Logic Controllers

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Solution Overview

Problem

Verification of temporal specifications in neural network-controlled systems is challenging due to the complexity of these systems and existing implementations that do not adequately address closed-loop system properties, particularly with Signal Temporal Logic (STL) specifications.

Innovation Solution

A system that identifies temporal logic associated with a neural network controller, generates a second neural network based on this logic, and computes a robustness metric to determine if the temporal specifications are met, effectively merging the two networks to validate the implementation of temporal logic specifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing verification methods are used for neural network controllers, then verification can be performed, but the verification is challenging and insufficient for complex systems with temporal specifications

Engineering Contradiction:
Improveverification accuracyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a verification neural network as an intermediary component that bridges the control neural network and the temporal logic specifications. This verification network takes the control network's output and the temporal logic formula as inputs, and produces a robustness metric that indicates whether the specifications are satisfied. The intermediary verification mechanism enables systematic verification of complex temporal properties without directly analyzing the entire closed-loop system, thus improving verification reliability while managing system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If temporal logic specifications are added to increase expressivity, then more comprehensive verification is possible, but verification becomes increasingly challenging

Engineering Contradiction:
Improvespecification expressivityVSAvoidverification difficulty
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements a feedback mechanism where the verification neural network computes a robustness metric that quantifies how well the control network satisfies temporal logic specifications. This robustness value provides feedback information about the degree of specification satisfaction, enabling gradient-based optimization during training. The feedback loop allows the control network to learn from verification results, improving both the expressivity of temporal specifications and the tractability of verification by guiding the network toward specification-compliant behaviors.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If a verification neural network is generated based on temporal logic, then robustness metric can be computed, but the process requires merging two networks which increases complexity

Engineering Contradiction:
Improverobustness metric precisionVSAvoidnetwork architecture complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the control neural network and the verification neural network into a single unified network architecture. The control network processes sensor inputs and generates control actions, while the verification network processes both the control network's outputs and the temporal logic specifications to produce a robustness metric. By merging these networks, the patent enables end-to-end training through backpropagation, where gradients from the verification loss can flow back through the control network, improving measurement precision of the robustness metric while managing architectural complexity through unified training procedures.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS20240281640A1Neural network verification for neural network controllers
Publication Date: 2024.08.22 TOYOTA MOTOR ENG & MFG NORTH AMERICA INC
  • US20240281640A1 patent drawing
  • US20240281640A1 patent drawing
  • US20240281640A1 patent drawing

AI summary

Apparatuses, systems, and methods relate to technology to identify temporal logic that is associated with a controller of a physical system simulation, where the controller a first neural network. The technology generates a second neural network based on the temporal logic, and generates, with the second neural network, a robustness metric of the first neural network.