Download Problem Definition - Michigan Technological University

Field Data Acquisition
Abstract
The objective of this project is to search for a suitable measurement apparatus,
such as the accelerometer, force transducer, pressure transducer and thermocouple, and
verify the measurement parameter, such as the measurement bandwidth, measurement
sample rate and measurement voltage range, to use with the clothes washer and dryer.
These measurement apparatus will be used with the associated portable data acquisition
device attached to the measurement target to acquire operating data in a normal
household under conventional daily use. It is important to know the valid measurement
parameters together with the valid measurement apparatus due to the environment in
which the measurement apparatus will be placed in is far more complicated than the
controlled laboratory environment. Where the results gathered from the latter, a
controlled environment can be well maintained at constant level but the former is always
affected by many unknown factors. This report presents measurement results simulated
and measured as close as possible with respect to the “real” environment.
Created by Phie Theng Lee
Michigan Technological University
1
Field Data Acquisition
Introduction
~ This section provides the background information for this project.
~ The problem definition is stated together with the goals of this project.
Background
Household appliance designers, such as Whirlpool, aim to create the best
appliances and develop validation tests to support and compare their designs if the results
obtained from the laboratory testing condition were matched with the results from actual
operating condition.
With the functional clothes washer and dryer under the same well-maintained
laboratory conditions, the comparable results, such as the heat generated by the clothes
dryer’s heating element or the spin speed generated by the clothes washer’s drive motor,
could be obtained with ease in any time frame. Tests performed in the laboratory could
only account for several instances, several normal situations that are valid up to a certain
range defined by the engineering team. For example, the foot force and the heat on the
coil of the clothes washer’s drive motor during the Rinse and Spin state. These tests do
not account for the random occurrences of mistakes make by the operator, such as
overloading the clothes washer or forgetting to clear the clothes dryer’s lint screen. These
tests perform well with an optimal level of consistency, but are completely dissimilar to
any “real world” situation for those clothes washers and clothes dryers. Laboratory
testing includes a worst cases scenario, but unfortunately random and unexpected
scenarios are not testable, they can only happen in a random time frame and each
occurrence is thus unique.
Created by Phie Theng Lee
Michigan Technological University
2
Field Data Acquisition
A company, such as Whirlpool, will send a product to production if their
engineering team validated their design in laboratory testing conditions. With validation
and operational data acquired in field operating conditions, the engineering team could
further improve their product.
Created by Phie Theng Lee
Michigan Technological University
3
Field Data Acquisition
Problem Definition
The purpose of this project is to setup the measurement apparatus for clothes
washer and clothes dryer. Knowing the target to measure, using the associated portable
measurement device is trivial. For example, a novice could use a thermometer to measure
his or her body temperature, or the temperature of an object. The biggest obstacle is to
determine which pieces of measured data, such as the voltage signal from the clothes
washer cabinet acceleration measurement or the clothes dryer temperature measurement,
are valid and useful. The problem of transporting the measured data back to the
laboratory for analysis must be considered also. For example, consider the playback of a
typical commercial advertisement on television channel; the audience will not be able to
tell which company was responsible from the beginning of the advertisement until it was
seconds or minutes after the start of the commercial advertisement. In this case, the target
is to know which company was responsible for the commercial advertisement and the
entire length of the measured data is the total playback time of the commercial
advertisement.
The problem includes several variables, such as size of the data, method in
transporting and whether to transport the entire measured data or only transport the most
useful pieces of the data. All of these are interrelated to each other. For example, the size
of data directly affects the method of transport, considering how much time it will take to
transport 100 MB (Megabytes) of data over a conventional phone line with the
inconsistent maximum speed of 56 kbps versus using the high-speed Ethernet connection
of 1.5 Mbps (Mega-bits per second) obtained through the widely available cable modem.
Since the acquisition device attached to the clothes washer and dryer is often located in
Created by Phie Theng Lee
Michigan Technological University
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Field Data Acquisition
the basement of a household, the possibility of using the conventional phone line may be
much easier to access and more cost effective compared with using the Ethernet
connection, provided both methods of transport are available in the household.
Additionally, the uploading or transporting period could only be performed at the period
where minimal interruption is possible. It is true that with a high-speed connection, in this
case the Ethernet connection, more data could be transported at any specific time.
More data does not always mean the information contained within the data is
useful. Consider a vehicle traveling at a constant speed of 55 mph for two hours. If a
passenger in the vehicle were to write down the traveling speed of the vehicle within that
two hours time frame shall he or she do that every minute, every second, every fifteen
minutes or every half an hour ? The passenger might only require writing down the
traveling speed of the vehicle once within the two hours time frame since he or she
knows that the traveling speed of the vehicle will not be changing over that time frame.
More data in this case does not mean better. The goal is to have a piece of data that is as
informative as possible within the possible range of minimal data size.
Created by Phie Theng Lee
Michigan Technological University
5
Field Data Acquisition
Project Purpose
This project will consist of measurements taken at different sample rates with
different apparatus at the same measuring location. The differences in measured data will
take into account each individual sample rate. Theoretically, there should not be any
differences on the content of the measured data if every other variable is held as constant
as possible, by only varying the sample rate. In reality this condition is incredibly
difficult to replicate even if the test is run in a well-controlled environment. As stated
previously, the current goal is to lower the size of the data without losing the important
content of the data, as well as utilizing the appropriate transducer for different aspect of
measurement. For example, using the proper type of thermocouple with respect to the
measurement temperature range and the responsiveness of the thermocouple as oppose to
how frequently data should be taken with respect to that measurement. This could be
achieved by controlling the sample rate when making the measurement and by knowing
which part of the entire data set will be useful and important for further analysis. The
analysis could either be performed within the associated portable acquisition device
before transporting the data back to the main storage, or after being transported back to
the main storage. In this study, the performance, such as the amount of foot force
generated by the clothes washer during Spin state, of the clothes washer and dryer are
monitored and the best measurement parameters, such as the proper sample rate, are
developed.
Created by Phie Theng Lee
Michigan Technological University
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