Propulsion Torque Calculation Using Internal Torque Estimation

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Solution Overview

Problem

The existing methods for determining propulsion torque on a test stand face challenges due to noisy and insufficiently resolved measurement signals for shaft torque and angle of rotation, which complicates the calculation of high-quality propulsion torque, especially when ancillary units are not present or accurately measured.

Innovation Solution

The method involves measuring internal torque and using it in an equation of motion to estimate a correction torque, which is then used to calculate the propulsion torque, accounting for influences like friction and ancillary units, with the option to model this correction torque based on angular velocity and continuously correct it for improved accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If shaft torque and angle of rotation are measured directly on the test stand, then the propulsion torque can be calculated, but the measurement signals are noisy and insufficiently resolved, leading to poor calculation quality

Engineering Contradiction:
Improvepropulsion torque calculation qualityVSAvoidmeasurement signal quality
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces an intermediary estimation process using the equation of motion as a mediator between the noisy direct measurements and the final propulsion torque calculation. By using the relationship M_dyn = M_V + M_W and estimating M_V through this intermediate equation, the system achieves better calculation quality than direct measurement would provide.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical measurement of shaft torque with a computational approach using the equation of motion. Instead of relying solely on noisy mechanical sensors, the system substitutes the measurement process with a mathematical model that combines available measurements with physical laws to derive the propulsion torque.

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

2Reliability

If ancillary units are installed on the test bench to measure all torque influences, then complete torque accounting is achieved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvetorque measurement completenessVSAvoidtest stand configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the ancillary unit torques from the direct measurement requirement and represents them virtually through the estimation process. Instead of physically installing and measuring each ancillary unit's torque separately, the system extracts this information through the equation of motion estimation, eliminating the need for complex physical measurement setups.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a virtual copy of the ancillary units' torque influence through the estimation model. Rather than requiring physical presence and direct measurement of all ancillary components, the system replicates their torque effects computationally, allowing complete torque accounting without physical complexity.

Inventive Principle:
Principle #26Copying

3Measurement precision

If the correction torque is estimated using the equation of motion with measured internal torque, then high-quality propulsion torque is achieved, but the measurement and calculation complexity increases

Engineering Contradiction:
Improvepropulsion torque resolutionVSAvoidmeasurement and calculation system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the equation of motion serve multiple functions: it acts as both a physical model representing the system dynamics and as a calculation tool for estimating the correction torque. This multi-functionality allows the same mathematical relationship to provide both system understanding and precise measurement without requiring separate complex systems.

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

Solution Approach 2:

The patent implements feedback by using the measured internal torque from the torque generator to continuously update and refine the correction torque estimation through the equation of motion. This feedback loop ensures that the estimation adapts to actual system conditions, improving precision while using the same measurement infrastructure.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3224589B1Method and a device for determining the propulsion torque
Publication Date: 2020.04.22 AVL LIST GMBH
  • EP3224589B1 patent drawingFigure 1
  • EP3224589B1 patent drawingFigure 2
  • EP3224589B1 patent drawing

AI summary

The problem addressed by the invention is that of providing a qualitatively high-grade propulsion torque of a torque generator in a simple way for a test run from sometimes qualitatively poor measuring variables available on the test stand. This problem is solved in that an inner torque (Mi) of the torque generator (D) is measured, and based on the measured inner torque (Mi), a correction torque (Mcorr) is estimated from a motion equation with the measured inner torque (Mi), a dynamic torque (Mdyn), and a shaft torque (Mw) measured on an output shaft (8) of the torque generator (D). From the estimated correction torque (Mcor) and the measured inner torque (Mi), the propulsion torque (Mv) is calculated according to the equation Mv = Mcor + Mi.