Long Stator Linear Motor Control Zone Transition

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Solution Overview

Problem

The existing control structures for long-stator linear motors require complex communication and data transfer between segment controllers to ensure seamless movement of transport units across segment boundaries, increasing computing effort and complexity.

Innovation Solution

The method involves expanding control zones by virtual drive coils, allowing a single segment control unit to calculate and transmit manipulated variables directly to the next zone, reducing the need for position and propulsion force data transfer, and enabling a balanced distribution of computing power between control units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex communication and data transfer between segment controllers is implemented to ensure seamless movement across segment boundaries, then movement continuity is improved, but computing effort and system complexity increase

Engineering Contradiction:
Improvemovement continuityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the control functions of multiple segment controllers by having the first segment controller assume responsibility for controlling drive coils in both the first and second control zones. This consolidation eliminates the need for complex inter-controller communication and data transfer, while maintaining seamless movement continuity through direct control of all necessary drive coils from a single controller.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If position and propulsion force data are transferred between segment controllers, then control accuracy is improved, but computing effort and communication overhead increase

Engineering Contradiction:
Improvecontrol accuracyVSAvoidcomputing effort
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent extracts and eliminates the unnecessary data transfer step between segment controllers. By having the first segment controller directly control drive coils in both control zones, the system removes the need to transfer position and propulsion force data to the second segment controller, thereby reducing computing effort and communication overhead while maintaining control accuracy through direct manipulation of drive coil currents.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This simplifies the transition process by reducing computing effort and eliminating the need for position and propulsion force data transfer, ensuring seamless movement across control zones with direct assignment of virtual drive coils to actual drive coils.

Implementation Method 1

By selectively activating the drive coils, in particular by applying a corresponding coil voltage to generate a drive current, a magnetic field moving in the direction of movement along the conveyor section can be generated

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

drive magnets (permanent or electromagnets) are arranged on a transport unit, which interact with the magnetic field generated by the drive coils

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP3422558B1Long stator linear motor and method for moving a transport unit of a long stator linear motor
Publication Date: 2020.06.10 B&R IND AUTOMATION GMBH
  • EP3422558B1 patent drawingFigure 1
  • EP3422558B1 patent drawingFigure 2
  • EP3422558B1 patent drawingFigure 3a~3d

AI summary

To simplify the transition of a transport unit of a long-stator linear motor across control zones (RZk, RZk+1) with a number of drive coils (ASk.1, ..., ASk.m, ASk+1.1, ..., ASk+1.m), where each control zone (RZk, RZk+1) is controlled by a segment control unit (SRk, SRk+1), it is provided that when the transport unit (Tn) transitions from the first control zone (RZk) in the direction of motion (x) to the subsequent second control zone (RZk+1), the first segment control unit (SRk) initially remains responsible for controlling the movement of the transport unit (Tn), and the first control zone (RZk) in the direction of motion (x) is extended by a number (j) of virtual drive coils (ASk.m+1, ..., ASk.m+j), and the first segment control unit (SRk) assigned to the first control zone (RZk) also provides the necessary manipulated variables for the required virtual drive coils (ASk.m+1, ..., ASk.m+j) calculates, the first segment control unit (SRk) transmits the required control variables for the required virtual drive coils (ASk.m+1, ..., ASk.m+j) to the second segment control unit (SRk+1) assigned to the second control zone (RZk+1), and the second segment control unit (SRk+1) uses the transmitted control variables for the required virtual drive coils (ASk.m+1, ... , ASk.m+j) to energize the drive coils (ASk+1.1, ..., ASk+1.m) of the second control zone (RZk+1) required for moving the transport unit (Tn).