Linear Motion Control for Multiple Carrier Positioning

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Solution Overview

Problem

Existing linear motion systems face challenges in controlling multiple product carriers independently, particularly in managing conflicts and ensuring accurate positioning due to limitations in controlling carriers at different velocities and determining which coil unit is closest to a carrier within the interaction range.

Innovation Solution

The method employs sensor devices with Hall sensors to generate position-dependent detection signals, allowing for precise control of product carriers by activating coil units sequentially and determining control ranges and overlap zones to manage carrier interactions and positioning accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensor devices are provided to detect the movement of product carriers and generate position-dependent detection signals for accurate positioning, then positioning precision is improved, but device complexity increases due to the need to manage multiple sensors, coil units, and control ranges

Engineering Contradiction:
Improvepositioning precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The transport circuit is divided into multiple control ranges, each associated with a specific coil unit. Each control range is further divided into a control zone and an overlap zone with adjacent ranges. This segmentation allows the system to manage multiple carriers independently by assigning each to a specific control range, reducing the complexity of managing all carriers simultaneously while maintaining precise positioning through localized control.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If independent control of multiple product carriers is implemented using separate coil units, then adaptability is improved, but conflicts arise when carriers are within the interaction range of multiple coil units simultaneously

Engineering Contradiction:
Improveindependent carrier controlVSAvoidcarrier positioning reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system pre-defines control ranges and overlap zones for each coil unit before carriers enter these zones. When a carrier enters an overlap zone, the system has already prepared the transition protocol to switch control from one coil unit to another. This preliminary preparation prevents conflicts and positioning errors that would occur if control decisions were made reactively when conflicts arise.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system dynamically assigns carriers to specific coil units based on their real-time positions and the defined control ranges. When a carrier moves from one control range to another, the system dynamically transitions control authority. This dynamic approach allows the system to adapt to varying carrier positions and velocities while maintaining reliable control by ensuring each carrier is always assigned to exactly one active coil unit.

Inventive Principle:
Principle #15Dynamics

3Speed

If the magnetic travelling-field is generated by applying variable frequency and amplitude current to coil units, then speed control is improved, but it becomes difficult to control two carriers at different velocities with one coil

Engineering Contradiction:
Improvecarrier velocity controlVSAvoidmulti-carrier velocity control
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The system segments the transport circuit into multiple control ranges, each with its own coil unit. This segmentation allows different coil units to operate independently with different current frequencies and amplitudes, enabling simultaneous control of multiple carriers at different velocities. Each coil unit can be optimized for the specific speed requirements of carriers within its control range without interfering with other carriers controlled by different coil units.

Inventive Principle:
Principle #1Segmentation

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 approach enables more versatile and accurate independent control of product carriers, preventing collisions and ensuring precise positioning for process actions, such as semiconductor layer deposition, by defining control and overlap ranges and using hysteresis zones to manage carrier transitions.

Implementation Method 1

sensor devices with Hall sensors to generate position-dependent detection signals

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 2

A magnetic travelling-field is generated for moving the translator(s)... applying a three-phase current to said coil units

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP2182621B1Method and apparatus for controlling a linear motion system
Publication Date: 2012.06.06 ROBERT BOSCH GMBH
  • EP2182621B1 patent drawingFigure 1~2
  • EP2182621B1 patent drawingFigure 3a~3b
  • EP2182621B1 patent drawingFigure 4

AI summary

This invention relates to a method of controlling a linear motion system having a linear synchronous motor comprising a stator and at least one carrier unit (10a, 10b) moveable in relation to said stator which comprises at least one coil unit (30a, 30b, 30c) including at least one sensor unit (7a, 7b, 7c) for determining the position of said at least one carrier unit (10a, 10b) and at least one coil (5a, 5b, 5c) for moving said at least one carrier unit (10a, 10b) wherein in case different carrier units are within a control range of one coil unit, the carrier unit to be controlled by said coil unit is determined as a function of the position of said carrier units and/or wherein in case a carrier unit.is within an overlap control range of two different coil units, the coil unit, which is to control said carrier unit, is determined as a function of the position of said carrier unit.