Actuator Position Recovery After Power Loss Without Stop Referencing

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Solution Overview

Problem

Existing methods for adjusting the position of an actuator after a power supply interruption require frequent referencing and plausibility checks, which are resource-intensive and limit the number of allowed shutdowns to protect the battery, but these processes need to be performed more frequently than currently possible.

Innovation Solution

The method involves storing a significant parameter value characterizing the actuator's position non-volatilely and comparing it with the current value after power restoration, preventing unnecessary referencing by checking if the difference falls below a threshold, thus ensuring the actuator returns to its correct position without needing to approach additional stops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If referencing and plausibility checks are performed frequently to ensure actuator position accuracy after power supply interruption, then the reliability of actuator position is improved, but the service life of the actuator stop is reduced due to excessive mechanical wear

Engineering Contradiction:
Improveactuator position accuracyVSAvoidactuator stop service life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the detection parameter from mechanical stop position to electrical parameter (counter value) stored in non-volatile memory. By comparing the stored counter value with the current counter value after power restoration, the system determines actuator position without mechanical contact, thus extending stop service life while maintaining position accuracy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical referencing process (physical contact with stop) with an electrical/electronic system using non-volatile memory storage and counter value comparison. This substitution eliminates mechanical wear during position verification while maintaining the ability to detect and correct position deviations.

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

2Loss of energy

If the actuator is disconnected from power supply frequently to protect the battery, then the energy consumption is reduced, but the actuator position accuracy deteriorates due to loss of reference information

Engineering Contradiction:
Improvebattery consumptionVSAvoidactuator position accuracy
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent performs preliminary action by storing the counter value in non-volatile memory before power supply interruption. This pre-stored value serves as reference information that allows the system to restore actuator position accuracy without requiring frequent re-referencing, thereby enabling more frequent power disconnections for battery protection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses its own stored counter value from non-volatile memory to self-verify and restore actuator position after power interruption. This self-service capability eliminates the need for external referencing operations, allowing frequent power cycles without compromising position accuracy.

Inventive Principle:
Principle #25Self-service

3Reliability

If referencing is performed every time the actuator is disconnected from power supply to maintain position accuracy, then the actuator position reliability is improved, but the device complexity increases due to additional referencing mechanisms

Engineering Contradiction:
Improveactuator position accuracyVSAvoidreferencing mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a copy of the actuator position information by storing the counter value in non-volatile memory. This copied information serves as a reference that can be compared with the current position after power restoration, eliminating the need for complex mechanical referencing mechanisms while maintaining position accuracy.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3959486B1Method of setting a position of an actuator after interruption of a power supply
Publication Date: 2024.05.08 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3959486B1 patent drawingFigure 1
  • EP3959486B1 patent drawingFigure 2

AI summary

The invention relates to a method for adjusting a position of an actuator following an interruption in a voltage supply, in which a parameter value of a component (6) actuating the actuator (1) is captured, wherein the parameter value is used to determine an actuator position which is referenced and checked for plausibility after the supply voltage has been restored. In a method in which the referencing and plausibility-checking strategy is simplified, referencing is prevented if the actuator (1) is correctly shut down following an interruption in the voltage supply.