Test Bench Control Using State Observer Torque Estimation

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Solution Overview

Problem

Existing test bench technologies struggle to simultaneously estimate the rotational speed and torque of test specimens, particularly in electric motor test benches, due to the absence of direct measurement capabilities, which is crucial for monitoring power dissipation and avoiding thermal overload, and existing methods are complex or inaccurate.

Innovation Solution

A method involving a first system of differential equations to model the rotational behavior of the test rig arrangement, combined with a second system to model the test specimen torque using autonomous exosystems, allowing for the estimation of rotational speed and torque through a state observer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors are installed to directly measure rotational speed and torque of the test specimen, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improverotational speed and torque measurementVSAvoidsensor installation and cabling
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of the measurement system by implementing a mathematical model that replicates the behavior of physical sensors. The state observer algorithm generates virtual measurement signals for rotational speed and torque by processing data from existing sensors (accelerometer, gyroscope, magnetometer) through a dynamic model of the test specimen and mounting structure, eliminating the need for direct physical sensor installation on the test specimen.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent introduces an intermediary mathematical model and state observer algorithm that mediates between the available sensor data and the desired measurement information. This intermediary processing layer transforms measurements from the mounting structure into accurate estimates of test specimen rotational speed and torque through dynamic modeling, avoiding direct sensor-test specimen contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If additional sensors are installed to capture dynamic operating conditions, then measurement precision is improved, but ease of operation deteriorates due to increased cabling and setup time

Engineering Contradiction:
Improvedynamic operating condition monitoringVSAvoidtest bench setup and modification
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The virtual sensor system creates digital replicas of physical sensor functionality through mathematical modeling. By copying the measurement capability through software-based state estimation rather than physical sensor installation, the system maintains high measurement precision for dynamic conditions while eliminating the operational burden of cabling, sensor installation, and hardware modification during test setup changes.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent changes the measurement approach from physical parameter sensing to computational parameter estimation. By transitioning from direct physical measurement to mathematical model-based estimation, the system achieves the same monitoring capability without the operational constraints of physical sensor deployment, allowing rapid reconfiguration for different test specimens.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If physical sensors are used to measure test specimen parameters, then measurement precision is improved, but adaptability deteriorates when test specimens do not allow measurement data acquisition

Engineering Contradiction:
Improverotational speed and torque dataVSAvoidcompatibility with different test specimens
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The virtual measurement system copies sensor functionality through mathematical modeling rather than physical contact. This allows the system to obtain rotational speed and torque data for any test specimen type (electric motors, internal combustion engines, turbines) without requiring specimen-specific sensor installation or modification, as the state observer processes data from the mounting structure applicable to all specimen types.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent creates a universal measurement solution that functions across diverse test specimen types through a unified mathematical model approach. The state observer and dynamic model provide a multi-functional platform that adapts to different specimens (electric motors, combustion engines, turbines) without requiring specimen-specific hardware configurations, achieving both precision and universality.

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

Data Source

PatentEP4348211B1Procedure for controlling a test bench arrangement
Publication Date: 2026.01.21 AVL LIST GMBH
  • EP4348211B1 patent drawingFigure 1
  • EP4348211B1 patent drawingFigure 2
  • EP4348211B1 patent drawingFigure 3

AI summary

In order to provide a method that improves on the prior art for regulating a test bench arrangement (4) in which a rotating specimen (1) is connected to a rotating loading machine (2) via a mechanical shaft connection (3) and in which at least one angular velocity prevailing in the test bench arrangement (4) is measured, the rotational behaviour of the test bench arrangement (4) and thus the dynamic behaviour at least of the measured angular velocity and of a specimen angular velocity (ωP) prevailing in the specimen (1) is first of all modelled using a first differential equation system. Building on this, the specimen torque (TP) generated by the specimen (1) is modelled using a second differential equation system, a state observer for estimating the specimen angular velocity (ωP) and the specimen torque (TP) is developed on the basis of the first and second differential equation systems, estimates of the specimen angular velocity (Formula (I)) and of the specimen torque (ŤP) are ascertained based on the state observer, and the ascertained estimates are used to regulate at least one regulation angular velocity prevailing in the test bench arrangement (4) and/or at least one regulation torque prevailing in the test bench arrangement (4).