Interpretable Neural PID Control for Nonlinear Plant Stability

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Solution Overview

Problem

The lack of interpretability in artificial neural networks used for control applications, particularly in high-stakes fields like high-power converter circuits, makes it difficult to formulate an adequate validation strategy, leading practitioners to prefer classical regulation schemes despite their limitations in handling nonlinearities.

Innovation Solution

Development of interpretable artificial neural networks that implement reinforcement learning strategies, specifically designed to provide a mathematically sound validation approach by integrating proportional-integral-derivative (PID) control functions, enabling understanding of how the neural network performs its control functions and allowing for the use of neural networks in nonlinear control applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If classical regulation schemes like PID control are used, then stability and interpretability are ensured, but the ability to handle nonlinearities is insufficient

Engineering Contradiction:
ImprovestabilityVSAvoidability to handle nonlinearities
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent merges classical PID control structure with neural network learning capabilities. The controller combines the interpretability and stability guarantees of PID control with the adaptive nonlinear handling of neural networks, creating a hybrid controller that achieves both reliability and adaptability to nonlinear systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hybrid controller serves multiple functions: it provides classical PID control for stability and interpretability while simultaneously incorporating neural network components for adaptive nonlinear compensation. This multi-functional design allows the system to handle both linear and nonlinear dynamics effectively.

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

2Adaptability or versatility

If artificial neural networks are used for control, then adaptability to nonlinear systems is improved, but interpretability and validation become difficult

Engineering Contradiction:
Improvehandling of nonlinearitiesVSAvoidinterpretability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The controller segments the control function into distinct components: a classical PID part that provides interpretability and a neural network part that handles nonlinear adaptation. This segmentation allows each component to fulfill its specific role while maintaining overall system interpretability through the structured combination.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary layer that connects the neural network outputs to the classical PID control structure. This intermediary ensures that the neural network's adaptive capabilities are integrated in a controlled manner that preserves interpretability and allows for validation through the structured control framework.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If classical PID control is used, then interpretability is maintained, but time-intensive parameter tuning is required

Engineering Contradiction:
ImproveinterpretabilityVSAvoidparameter tuning time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The neural network component performs self-learning and automatic parameter adaptation, eliminating the need for manual time-intensive tuning of PID parameters. The system automatically adjusts its control parameters based on learned patterns from training data, significantly reducing the time required for parameter optimization while maintaining interpretability through the classical control structure.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If reinforcement learning is applied to control problems, then flexibility is improved, but understanding of network behavior and validation become difficult

Engineering Contradiction:
ImproveflexibilityVSAvoidunderstanding of network behavior
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent incorporates feedback mechanisms that provide information about the neural network's behavior and performance. Through the structured hybrid architecture, the system provides feedback loops that maintain transparency into how the neural network influences control decisions, allowing practitioners to understand and validate network behavior while retaining the flexibility of reinforcement learning.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS20230117488A1Interpretable Neural Networks for Nonlinear Control
Publication Date: 2023.04.20 INFINEON TECH AUSTRIA AG
  • US20230117488A1 patent drawing
  • US20230117488A1 patent drawing
  • US20230117488A1 patent drawing

AI summary

A controller circuit implements an interpretable neural-network-based proportional integral derivative (PID) control function. The controller circuit comprises a controller output signal for input to a nonlinear plant, a controller input signal representing an error in an output of the nonlinear plant, and a neural network configured to calculate the controller output signal from the controller input signal by summing a first signal depending on a current value of the controller input signal, a second signal generated at least in part by a first neural network estimating a differential of the controller input signal, and a third signal generated at least in part by a second neural network estimating an integral over time of the controller input signal.