Conveyor Weight Detection via Motor Speed Fluctuation
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Solution Overview
Problem
Conveyor systems require costly load cells and complex control systems for weight measurement, leading to increased manufacturing costs and potential operational issues.
Innovation Solution
A conveyor system with two zones, each driven by a motor at a constant rotation speed, uses rotation speed sensing and calculation to estimate the weight of a transport object based on fluctuations in motor speed when the object is moved between zones, eliminating the need for load cells and simplifying control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a load cell is used for weight measurement, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces the mechanical load cell system with an electrical measurement system. Instead of using a load cell to directly measure weight, the system uses a motor's electrical parameters (current, voltage, frequency) and control data to calculate weight. This substitution eliminates the need for mechanical weight sensing components and their associated complex control systems, thereby reducing device complexity while maintaining measurement capability.
Solution Approach 2:
The patent introduces the motor as an intermediary element between the transport object and the measurement system. The motor's electrical characteristics serve as a mediator to indirectly measure the weight of the transport object. By monitoring how the motor's electrical parameters change when carrying different weights, the system can calculate weight without direct mechanical contact, thus simplifying the overall device structure.
2Measurement precision
If a load cell is used for weight measurement, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces the expensive mechanical load cell system with a more cost-effective electrical measurement approach using existing motor components. This substitution eliminates the need to purchase and install specialized weight measurement hardware, thereby significantly reducing manufacturing costs while maintaining the ability to measure weight through electrical parameter analysis.
Solution Approach 2:
The patent makes the motor serve dual purposes: both driving the transport object and measuring its weight. The motor's existing electrical sensors and control systems are utilized for weight measurement, eliminating the need for separate dedicated weight measurement components. This self-service approach reduces overall system cost by leveraging existing infrastructure.
3Measurement precision
If conventional weight measurement methods are used, then measurement precision is improved, but the number of components increases
Solution Approach 1:
The patent merges the weight measurement function with the existing motor drive system. Instead of adding separate weight measurement components, the system combines weight measurement capabilities into the motor control unit by analyzing electrical parameters. This merging reduces the total number of components while maintaining measurement precision through integrated sensing and calculation.
Solution Approach 2:
The patent makes the motor system multi-functional by enabling it to perform both its primary function of driving the transport object and the secondary function of measuring weight. The same motor and its electrical sensors serve dual purposes, eliminating the need for dedicated weight measurement components and thereby reducing the overall component count in the system.
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 accurate weight measurement of transport objects without specialized weight measuring devices, reducing costs and operational complexity while maintaining high carriage efficiency.
Implementation Method 1
calculate weight of a transport object based on fluctuation of the rotation speed of one of the motors when the transport object is moved from one zone to the other zone
Data Source
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AI summary
It is an object of the present invention to provide a conveyor which estimates weight of a transport object while it is carried without using devices such as a load cell which directly measures weight. The conveyor has a plurality of zones forming a series of carriage ways. An approach-run zone and a weight-measurement zone are arranged adjacently in the conveying direction and are provided with different drive motors. The drive motor of the approach-run zone and the drive motor of the weight-measurement zone are controlled with respectively different predetermined rotation speeds as their target rotation speeds. A rotation speed sensing means obtains the change of rotation speed of the drive motor in the weight-measurement zone when a transport object is conveyed into the weight-measurement zone from the approach-run zone, and a weight sensing means then calculates the weight of the transport object based on the change of the rotation speed.