Checkout Conveyor Motor Controller Phase Gating Torque Control

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Solution Overview

Problem

Conventional phase control methods for drive motors of goods conveyor belts at checkouts often result in jerky starts and stops, leading to tipping over of goods, and are costly to implement and maintain, especially in mass-produced supermarket systems.

Innovation Solution

A controller that initially drives the conveyor belt with unreduced torque during startup to overcome inertia, followed by phase control to achieve smooth acceleration and deceleration, eliminating the need for weight sensors and frequency converters, thus reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If phase control or phase section control is used to reduce initial torque for smooth startup, then the goods conveyor belt accelerates more gently, but goods can still tip over during startup and braking

Engineering Contradiction:
Improvesmooth accelerationVSAvoidgoods stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The startup process is divided into multiple phases: an initial phase with full torque to overcome inertia and move the belt, followed by a transition phase where phase control gradually reduces torque. This segmentation allows the system to overcome the limitation of pure phase control by providing sufficient initial force while maintaining smooth operation throughout the acceleration process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system dynamically adjusts the torque profile based on the operational state. It transitions from a high-torque initial phase to a controlled reduction phase, creating an adaptive torque curve that responds to the changing mechanical conditions of the conveyor belt system during startup and braking.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If conventional phase control is used to reduce torque during startup, then acceleration is smoother, but the system requires additional expensive components like weight sensors and frequency converters

Engineering Contradiction:
Improvesmooth accelerationVSAvoidcontrol system cost
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The controller uses the existing phase control mechanism to automatically regulate torque without requiring external sensors or additional control components. The system self-regulates by manipulating the phase angle of the power supplied to the motor, eliminating the need for weight sensors, frequency converters, or other expensive add-on devices.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The controller performs multiple functions using a single integrated device: it provides both the phase control for smooth acceleration and the torque regulation for stable operation. This multi-functionality eliminates the need for separate specialized components, reducing overall system complexity and cost while maintaining performance.

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

Data Source

PatentEP3465899B1Controller and method for controlling a drive motor of a product conveyor belt at a checkout
Publication Date: 2023.07.05 INTERROLL HLDG
  • EP3465899B1 patent drawingFigure 1~2
  • EP3465899B1 patent drawingFigure 3
  • EP3465899B1 patent drawingFigure 4

AI summary

A controller for a drive motor (60) of a product conveyor belt at a checkout has a phase-gating and/or phase-chopping controller (50) which controls the drive motor (60) in such a manner that the product conveyor belt is accelerated with a reduced torque from a non-driven state. A starting controller controls the drive motor (60) in such a manner that the drive motor (60) initially drives the product conveyor belt with a non-reduced torque when accelerating the product conveyor belt from the non-driven state before the phase-gating and/or phase-chopping controller (50) further accelerates the product conveyor belt with the reduced torque.