Control Signal Quality Assessment for Ill-Conditioned QP Solvers

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Solution Overview

Problem

Existing optimization-assisted automatic control techniques for underdetermined control allocation problems in electric vehicles face challenges due to erroneous outputs from numerical optimization solvers, particularly in ill-conditioned problems, which can lead to inaccurate control signals and potential hazards.

Innovation Solution

A method for assessing the quality of solutions from optimization processes configured to solve constrained quadratic problems, involving the execution of an active-set optimization process, transformation into an associated unconstrained problem, and comparison of solution vectors to generate a quality indicator, thereby identifying unreliable solutions and preventing their use in control signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If numerical optimization solvers are used to solve control allocation problems in electric vehicles, then the control coordination can be optimized, but erroneous outputs may be produced due to convergence problems and instabilities in ill-conditioned problems

Engineering Contradiction:

Improvecontrol coordination efficiencyVSAvoidsolution accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent transforms the constrained quadratic optimization problem into an unconstrained form by changing the problem parameters and formulation. This transformation modifies the condition number and numerical properties of the problem, making it less susceptible to solver errors and instabilities while preserving the essential control allocation objectives

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a simplified copy of the original constrained optimization problem in unconstrained form. This copied problem serves as a computational surrogate that can be solved more reliably, and its solution is then mapped back to the original problem space to obtain the control allocation solution

Inventive Principle:

Principle #26Copying

2Reliability

If redundant optimization processes are used to verify solution quality, then solution reliability can be improved, but computational cost and processing time increase

Engineering Contradiction:

Improvesolution verification accuracyVSAvoidcomputational energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the essential verification function from a full redundant optimization process. Instead of running complete duplicate optimizations, it extracts and uses only the necessary computational elements (solving the unconstrained version) to verify solution quality, significantly reducing computational overhead while maintaining verification effectiveness

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial verification action rather than complete redundant optimization. By solving only the unconstrained version and comparing key solution aspects, it achieves sufficient verification for safety-critical applications without the excessive computational cost of full redundant processing

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If iterative optimization methods are used in real-time control systems, then complex control allocation problems can be solved, but the optimizer may not compute a good solution in the scheduled time

Engineering Contradiction:

Improvecontrol problem solving capabilityVSAvoidcomputation time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent employs a computationally inexpensive unconstrained optimization formulation that can be solved quickly and discarded each control cycle. This disposable approach replaces expensive iterative constrained optimization, enabling real-time solution of complex control allocation problems within scheduled time constraints

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS20250147475A1Method and device for assessing the quality of an optimization-based control signal prior to its use in a technical system

Publication Date: 2025.05.08 VOLVO TRUCK CORP

AI summary

A method for assessing the quality of a solution from an optimization process configured to solve a constrained quadratic problem (QP), the method comprising: initiating an execution of an active-set optimization process configured to solve the constrained QP; obtaining a first solution vector and an associated active set of constraints from the execution of the active-set optimization process; substituting variables in the constrained QP in accordance with the active set of constraints to form an associated unconstrained QP; initiating an execution of a second optimization process configured to solve the associated unconstrained QP; obtaining a second solution vector from the execution of the second optimization process; and generating a quality indicator for the first solution vector on the basis of a difference between the first and the second solution vectors.