Dual-Actuator Transmission Control for Backlash Concealment

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Solution Overview

Problem

Existing transmission devices face challenges in effectively concealing backlash without increasing gearing quality or accounting for wear, which affects reliability and efficiency.

Innovation Solution

The use of redundant electrical actuators and independent transmission branches, where the actuators are controlled to clamp against each other for torque requirements below a limit, allowing play concealment and contributing to output torque above that limit, thereby enabling reliable operation without enhancing gearing quality or considering wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spring-loaded bracing of partial gearboxes is used to conceal backlash, then backlash is concealed, but device complexity increases

Engineering Contradiction:
Improvebacklash concealmentVSAvoidspring-loaded bracing structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical spring-loaded bracing system with an electric actuator that applies preload forces to the gear teeth. This substitution eliminates the need for complex spring mechanisms while achieving the same backlash concealment effect through controlled electromagnetic actuation.

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

Solution Approach 2:

The patent dynamically adjusts the preload force applied by the electric actuator based on operating conditions such as torque requirements and wear state. By changing the preload parameter adaptively, the system maintains optimal backlash concealment without requiring fixed complex mechanical bracing structures.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If gear quality is increased to reduce play, then backlash is reduced, but manufacturing cost increases

Engineering Contradiction:
Improvebacklash reductionVSAvoidgearing quality
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of improving gear manufacturing quality to reduce backlash, the patent introduces an electric actuator that actively compensates for backlash through controlled preload application. This allows the use of standard-quality gears while achieving low-backlash performance through active control.

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

Solution Approach 2:

The electric actuator continuously monitors and compensates for backlash in real-time, allowing the transmission system to self-correct for gear wear and manufacturing tolerances without requiring high-precision manufacturing processes.

Inventive Principle:
Principle #25Self-service

3Reliability

If redundant actuators are used to conceal backlash, then reliability is improved, but device complexity increases

Engineering Contradiction:
ImproveredundancyVSAvoidredundant actuator system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The redundant electric actuator serves multiple functions: it applies preload to conceal backlash, provides backup drive capability, and can compensate for wear. This multi-functionality justifies the added component while delivering comprehensive reliability improvements beyond simple backlash concealment.

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

Solution Approach 2:

The control system automatically manages the redundant actuator, switching between actuators and adjusting preload forces based on real-time operating conditions. This automated self-management reduces the operational complexity despite the presence of redundant components.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4162177B1Method and control device for operating a transmission device and transmission device
Publication Date: 2024.03.20 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP4162177B1 patent drawingFigure 1
  • EP4162177B1 patent drawingFigure 2~3
  • EP4162177B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for operating a transmission device (100), in which a requested value of an output torque (M3) of the transmission device (10) is input and a first control signal (150) for controlling a first actuator (120) and a second control signal (160) for controlling a second actuator (130) of the transmission device (100) is determined according to the requested value. The control signals (150, 160) bring about input torques (M1, M2) which, according to the requested value of the output torque (M3), on the output side of the output shaft (118), cause moments with different signs and with different absolute values that are different from zero, or moments with the same signs and with the same absolute values that are different from zero.