Decentralized Master-Slave Control for Linear Motor Transfer Segments
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Solution Overview
Problem
Existing transfer apparatuses for workpiece carriers face challenges in synchronizing linear motors between segments for smooth and efficient transfer, leading to restricted speed ranges and system heating due to reliance on central control devices.
Innovation Solution
Implementing a master-slave relationship between adjacent segments' control units, allowing autonomous movement control and synchronization of linear motors through position measurement and signal communication, reducing the need for central control and enabling higher speeds during transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a central control device is used to synchronize linear motors between segments, then the workpiece carrier can be transferred between segments, but the speed range is restricted and the system generates excessive heat
Solution Approach 1:
The control system is divided into autonomous segment control units, each managing its own linear motor independently. During transfer phases, one segment becomes master and the other slave, eliminating the need for centralized control and enabling higher speeds without excessive heat generation from coordination overhead
Solution Approach 2:
The master-slave relationship between control units is dynamically established only during transfer phases rather than being static. This allows the system to adapt control architecture to operational needs, enabling high-speed operation during normal phases while providing coordinated control only when necessary for transfers
2Ease of operation
If a central control device coordinates segment synchronization, then linear motors can be synchronized, but autonomous movement control and precise speed regulation are limited
Solution Approach 1:
Each segment control unit is equipped with position measurement apparatus and autonomous control capability, allowing segments to independently determine when transfers are needed and initiate the master-slave relationship without external coordination, thereby enabling autonomous movement control
Solution Approach 2:
Position measurement apparatus in each segment provides real-time feedback on workpiece carrier location, enabling control units to autonomously detect transfer requirements and dynamically establish master-slave relationships based on actual operational conditions rather than centralized scheduling
3Measurement precision
If control signals are used to define commutation angle, then segment synchronization is achieved, but the actual speed deviates from nominal speed and static friction limits the speed range
Solution Approach 1:
Position measurement apparatus provides real-time feedback on workpiece carrier position, enabling control units to adjust commutation angles dynamically based on actual position rather than relying solely on predetermined signal timing, thereby improving speed accuracy and overcoming static friction limitations
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 reliable and high-speed transfer of workpiece carriers by decentralizing control, reducing system heating, and allowing for precise speed regulation, while maintaining synchronization of linear motors without central control device intervention.
Implementation Method 1
each segment having a long stator linear motor and a control unit for controlling the linear motor
Data Source
AI summary
In a transfer device for workpiece carriers (18), with a number of segments (10, 10′,10″) in which a control unit (14, 14′, 14″) respectively activates a linear motor (12,12′, 12″), in a phase of the transfer of the workpiece carrier (18) from a first segment (10) to a neighbouring segment (10′) synchronization of the linear motors (12, 12″) is no longer effected on the basis of control commands of a central controller but instead the control unit (14) of the first segment (10) makes itself the master (S18) and subjugates the control unit (14′) of the neighbouring segment (10′) as the slave (S20). A position measuring device (22, 24) makes it possible for the master control unit (14) to carry out speed control for the workpiece carrier (18). The control unit (14′) receives information on the commutation angle and the actual force value and can therefore issue the control commands to the associated linear motor (12′) for the control process.