Hamiltonian Control System Design for Nonlinear Stability

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Solution Overview

Problem

Current control system design methods are limited by their reliance on forcing nonlinear systems to behave like linear systems, which restricts their maximum potential performance and stability.

Innovation Solution

A novel nonlinear control design methodology based on thermodynamic exergy and irreversible entropy production concepts, representing physical apparatuses as Hamiltonian systems, analyzing stability through power flow, and employing Lyapunov optimal functions for performance and stability criteria.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional linear control design methods are used to force nonlinear systems to behave like linear systems, then the control system design becomes simpler and more conventional, but the maximum potential performance and stability of the nonlinear system is limited

Engineering Contradiction:
Improvecontrol system design complexityVSAvoidsystem stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent transforms the control system design by changing the fundamental parameters from linear approximations to thermodynamic parameters (exergy, entropy production rate). This allows the controller to be designed based on the actual nonlinear thermodynamic behavior of the system, achieving both high performance and stability without forcing the system to behave linearly

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical/mathematical linear control approaches with a thermodynamic-based control approach. By using exergy and entropy production rate as control parameters, the system naturally handles nonlinearities without requiring linearization or complex nonlinear control algorithms

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

2Reliability

If thermodynamic exergy and entropy production concepts are used for control system design, then necessary and sufficient conditions for stability are achieved, but the analysis and design process becomes more complex

Engineering Contradiction:
Improvesystem stabilityVSAvoidcontrol system design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a universal control framework based on thermodynamic principles that can be applied to any system with energy transformations. The exergy-based controller provides a unified approach that handles stability, performance, and optimization simultaneously, reducing the need for separate analysis methods for different system types

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

Data Source

PatentUS8121708B1Control system design method
Publication Date: 2012.02.21 NATIONAL TECHNOLOGY & ENGINEERING SOLUTIONS OF SANDIA LLC
  • US8121708B1 patent drawing
  • US8121708B1 patent drawing
  • US8121708B1 patent drawing

AI summary

A control system design method and concomitant control system comprising representing a physical apparatus to be controlled as a Hamiltonian system, determining elements of the Hamiltonian system representation which are power generators, power dissipators, and power storage devices, analyzing stability and performance of the Hamiltonian system based on the results of the determining step and determining necessary and sufficient conditions for stability of the Hamiltonian system, creating a stable control system based on the results of the analyzing step, and employing the resulting control system to control the physical apparatus.