Electronic Liquid Dispenser Motor Work Calculation for Jam Detection
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Solution Overview
Problem
Electronic dispensers face issues with liquid leakage or drainage due to motor jams or overruns, as existing control methods rely on single variables like timer or current monitoring, which are inadequate for detecting complex malfunctions.
Innovation Solution
A control method that calculates motor work based on current, voltage, and run time to dynamically determine if the pump mechanism is jammed, reversing the motor when calculated motor work exceeds a set point value to return the pump to its home position, thereby preventing liquid loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single variable monitoring (timer or current) is used to detect motor stalls, then the control method is simple, but the detection accuracy is insufficient leading to inadequate malfunction detection
Solution Approach 1:
The patent combines multiple monitoring variables (current, voltage, and time) into a unified motor work calculation system. Instead of relying on a single variable, the controller integrates these three parameters to compute motor work, which provides a more comprehensive and accurate indication of motor status and malfunction conditions.
Solution Approach 2:
The patent changes from monitoring individual parameters (current alone or time alone) to monitoring a derived parameter (motor work) that combines current, voltage, and time. This parameter transformation enables more precise detection of motor stalls and overruns by comparing calculated motor work against expected ranges.
2Measurement precision
If motor work calculation based on multiple variables is used, then the malfunction detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The controller performs multiple functions using the same set of sensors (current sensor and voltage sensor). These sensors feed data to the controller for both motor work calculation and other control functions, eliminating the need for additional dedicated hardware and reducing overall system complexity despite the enhanced monitoring capability.
Solution Approach 2:
The system implements feedback by continuously calculating motor work during operation and comparing it against expected ranges. When the calculated motor work falls outside the expected range, the controller identifies this as a malfunction condition (stall or overrun) and responds accordingly, creating a closed-loop monitoring system that improves detection accuracy without requiring complex additional hardware.
Data Source
AI summary
A system and control method for an electronic liquid dispenser utilizes a motor to drive a pump mechanism from a home position in a dispense cycle for dispensing a metered dose of liquid from a reservoir. Upon initiation of the dispense cycle, the motor is started to operate the pump mechanism. Motor work performed by the motor during the dispense cycle is calculated as a function of motor current, motor voltage, and run time of the motor. Upon the calculated motor work exceeding a set point value during the dispense cycle, the motor is stopped and reversed to return the pump mechanism to the home position.