Flat Good Length Measurement Using Dual Sensor Encoder Correction
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Solution Overview
Problem
Existing flat goods processing systems face measurement errors due to 'slippage' issues when determining the length of flat goods, particularly in systems that rely on encoder signals and photoelectric barriers, which can lead to inaccuracies in postage calculation and processing.
Innovation Solution
A method involving a control processor-connected encoder pulse counter and sensors in multiple stations to accurately measure the length of flat goods by counting encoder pulses and determining the difference between sensor events, ensuring minimal slippage and precise length measurement across various formats, using a path controller and photoelectric barriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If encoder signals are used to measure the movement of transport rollers, then the measurement process is automated, but measurement errors occur due to slippage between the roller and flat good
Solution Approach 1:
A second sensor is introduced as an intermediary measurement device that directly detects the flat good's position and movement, independent of the roller's encoder signals. This intermediary sensor system eliminates slippage errors by measuring the actual good movement rather than relying on roller rotation cues.
Solution Approach 2:
The patent replaces the mechanical encoder-roller measurement system with an optical/electronic sensor system that directly detects the flat good's leading and trailing edges. This substitution eliminates the mechanical slippage problem inherent in roller-based measurement systems.
2Device complexity
If only the movement of the roller is measured with encoder signals, then the measurement system is simpler, but the movement of the flat good cannot be accurately measured due to slippage
Solution Approach 1:
A second sensor acts as an intermediary that directly measures the flat good's movement independent of the roller. This adds minimal complexity while fundamentally solving the measurement accuracy problem by eliminating dependency on roller-good contact.
Solution Approach 2:
The system uses feedback from the second sensor to correct and verify the measurements from the encoder. By continuously monitoring the actual flat good position and comparing it with roller-based measurements, the system compensates for slippage errors.
3Productivity
If the gap between successive mail pieces is too small, then the processing speed increases, but the individualization process must be stopped to enlarge the gap
Solution Approach 1:
The system performs preliminary measurements of flat good dimensions using the dual sensor system before the individualization process begins. By pre-determining the exact length and position of each piece, the system can maintain optimal gaps without stopping for adjustments.
Solution Approach 2:
Real-time feedback from the second sensor allows continuous monitoring and adjustment of the individualization process. The system can dynamically adapt to varying gap sizes and flat good dimensions, maintaining processing continuity without manual intervention.
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 cost-effective, precise length measurement of flat goods, reducing measurement errors and ensuring accurate postage calculation before printing, with the ability to handle typical letter formats from postcards to B4 format.
Implementation Method 1
an encoder, which are connected with a control processor. The control processor is programmed to implement path control of the flat goods
Implementation Method 2
a sensor, which detects the leading edge and the trailing edge of a transported flat good during the transport
Data Source
AI summary
In a method and apparatus for length measurement of a flat good in a goods processing system having first and second stations, each having a sensor in the transport direction of the flat good, a control processor implements a path control and counts encoder pulses of an encoder in the first station. An event is determined by the sensor of the second station, and an associated numerical value Z1 of the encoder pulses is stored in the control processor, as is a numerical value Z2 for a distance between the two sensors is also stored. An additional event is determined by the sensor of the first station, and an associated numerical value Z3 of the encoder pulses is stored. As soon as both events are present, Z2 and the difference Δ=Z3−Z1 are added by the control processor, and the sum is used to designate the length.