Actuator Hard Stop Recalibration for Thermal Drift Compensation

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Solution Overview

Problem

Precise position control of variable position devices like valves is challenging due to factors such as thermal expansion and wear, leading to inaccuracies in actuator feedback, especially in harsh engine environments where components experience varying temperatures and conditions.

Innovation Solution

The method involves periodic recalibration of hard stop positions using initial calibration procedures, soft stop techniques to avoid collisions, collision detection to adjust actuator rates, and hard stop drifting procedures to account for position changes, ensuring accurate actuator feedback and precise control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the actuator operates in harsh engine environments with varying temperatures, then the variable position device can function under diverse conditions, but thermal expansion and wear cause inaccuracies in actuator feedback

Engineering Contradiction:
Improveoperating condition rangeVSAvoidactuator feedback accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary calibration procedures to establish hard stop positions before normal operation begins. This preliminary action accounts for thermal expansion and wear by pre-determining accurate reference positions that will be used during subsequent operation in harsh environments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements periodic recalibration of hard stop positions during operation. This periodic action compensates for thermal expansion and wear effects that accumulate over time, maintaining measurement precision despite varying operating conditions and temperatures.

Inventive Principle:
Principle #19Periodic action

2Speed

If the actuator moves quickly to adjust the variable position device, then response time is reduced, but collisions with hard stops occur causing damage and control errors

Engineering Contradiction:
Improveactuator response speedVSAvoidcollision-free operation
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The system applies preliminary anti-action by implementing soft stop techniques that preemptively reduce actuator speed before reaching hard stop positions. This prevents collisions by counteracting the high-speed movement before it causes damage, maintaining reliability while allowing fast operation throughout most of the travel range.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The system dynamically adjusts actuator speed based on position. The actuator operates at high speed when远离 hard stops to maintain fast response, but automatically reduces speed near hard stop positions to prevent collisions. This dynamic speed adjustment optimizes both response time and reliability.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the hard stop positions are fixed after initial calibration, then the control system is simple to operate, but thermal expansion and wear cause position drift over time

Engineering Contradiction:
Improvecontrol system simplicityVSAvoidhard stop position accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs periodic recalibration of hard stop positions during normal operation. This periodic action compensates for thermal expansion and wear-induced position drift without requiring complex manual intervention, maintaining measurement precision while keeping the control system relatively simple to operate.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system implements self-service through automatic recalibration procedures that adjust hard stop positions based on detected collisions or position errors. This self-correcting mechanism maintains position accuracy despite thermal expansion and wear, reducing the need for manual calibration while preserving measurement precision.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2274521B1Method for controlling an actuator
Publication Date: 2020.06.17 BORGWARNER INC
  • EP2274521B1 patent drawingFigure 1~1a
  • EP2274521B1 patent drawingFigure 2
  • EP2274521B1 patent drawingFigure 3

AI summary

A method for controlling an actuator, such as the type used to drive valves, vanes, and other variable position devices. In one exemplary embodiment, a method may improve the accuracy of actuator feedback by periodically or dynamically resetting the position of a lower hard stop, which can then be used as a future point of reference.