Linear Motor Control Switching Boundary Precision
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Solution Overview
Problem
Existing linear motor control systems for moving magnet type linear motors face challenges in precisely controlling multiple trucks at high speeds and high precision, especially when stopping at boundary positions between adjacent coil units, leading to reduced thrust and increased costs due to the need for double driving current.
Innovation Solution
A linear motor control apparatus comprising continuously arranged coil units, position detecting units, deviation calculating units, position control units, current control units, and a switching unit to transmit deviation information and current control signals, allowing for precise control of trucks by switching between motor controllers and current controllers based on detected positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If multiple coil units are arranged continuously to achieve long stroke conveyance, then the stroke length is improved, but the control precision at boundary positions deteriorates
Solution Approach 1:
The patent merges multiple coil units into continuous linear motor modules with overlapping control zones. Adjacent coil units are controlled by the same motor controller with coordinated current supply, eliminating boundary effects and enabling seamless long-stroke conveyance with uniform control precision throughout the entire stroke range.
Solution Approach 2:
The patent implements preliminary positioning control by calculating target stop positions that account for boundary locations between coil units. The control system proactively adjusts thrust distribution and current supply before the truck reaches boundary positions, ensuring high-precision stopping without requiring reactive corrections at boundaries.
2Device complexity
If one motor controller controls one truck to simplify control architecture, then the device complexity is reduced, but the productivity for controlling multiple trucks deteriorates
Solution Approach 1:
The patent designs motor controllers with multi-functionality to handle multiple trucks simultaneously. Each controller can independently manage multiple trucks on the same conveying path by processing individual position and velocity commands for each truck, enabling high-density truck arrangement and improved productivity without increasing controller quantity.
Solution Approach 2:
The patent segments the control of multiple trucks into independent control loops within each motor controller. Each truck receives dedicated position detection, deviation calculation, and current control signals, allowing parallel control of multiple trucks while maintaining a relatively simple overall control architecture.
3Force
If double driving current is supplied to one coil unit to maintain thrust at boundary positions, then the force is improved, but the use of energy and costs increase
Solution Approach 1:
The patent combines the driving force from multiple adjacent coil units to maintain consistent thrust on trucks near boundary positions. Instead of doubling current in a single coil unit, the system coordinates current supply across multiple coil units, achieving the same thrust level through distributed force contribution and reducing overall energy consumption.
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
Enables high-precision control of multiple trucks at high speeds by ensuring equal driving currents across coil units, reducing stop position restrictions and operational costs, and allowing for stable operation even near boundary positions.
Implementation Method 1
a magnet is arranged in a truck serving as a needle and a coil is arranged in a stator
Data Source
AI summary
A linear motor control apparatus has: a plurality of coil units; a plurality of position detecting units for detecting positions of a plurality of trucks which move over the plurality of coil units; a plurality of deviation calculating units for operating deviation information as differences between the detected truck positions and a target position of the detected truck; a plurality of position control units for operating current control signals based on the deviation information; a plurality of current control units for supplying driving currents to the coil units based on the current control signals; and a switching unit for switching the position control units to which the deviation information is transmitted or switching the current control units to which the current control signals are transmitted.