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/!\ ~+'''The version available now (version 0.0) is an alpha version; it was only tested by a limited amount of people. More testers/evaluators are very welcome!'''+~

Features in the pipeline

 * Option to change the minimum battery voltage

 * Filtering of the signal

[[BR]][[BR]]

[http://www.rcgroups.com/forums/showpost.php?p=13250870&postcount=8170 Preview of the GUI version]

== The command line ==

On Windows XP open a command shell by selecting Start>Run and typing "cmd".

On Windows Vista, click Start and type "cmd.exe" in the "Start Search" box.

Now, if you have for example unzipped the tool (the Pyhton version or the compiled version) in directory "D:\MK\VibrationToolExe" you should go to that directory by typing:

{{{

D:

cd \MK\VibrationToolExe

}}}

Now, the tool can be started by just typing "VibrationTest.py" if you have installed Python or "VibrationTest" if you use the compiled version. Without any parameters, it tool should display a description of the required parameters.

attachment:cmdLine.jpg

== The command line parameters ==

The tool expects to be started with a few parameters. When the tool is started without or invalid parameters, a brief description of the expected parameters is displayed:

{{{

VibrationTest.py COMPORT MOTORS SPEEDS CHANNELS [-m MINSPEED] [-s NBSAMPLES] [-n NAME] [-d FILENAME] [-v]

 COMPORT         Serial port to use. e.g. COM4

 MOTORS          Motors to activate during test. Multiple motors can be used at the same time. e.g. 1,2,3,4

 SPEEDS          Indicates at what speeds the motors need to be tested.

                   Format 1:  e.g. 50,110,140            Tests at speeds 50, 110 and 140

                   Format 2:  e.g. 100-200:50            Tests at speeds 100, 150 and 200

 CHANNELS        Channels to monitor. e.g. 5,6,7

                   Channel 0 = GyroYaw

                   Channel 1 = GyroRoll

                   Channel 2 = GyroNick

                   Channel 3 = Pressure

                   Channel 4 = Batt

                   Channel 5 = AccTop

                   Channel 6 = AccRoll

                   Channel 7 = AccNick

 -m MINSPEED     Minimum speed of the motor(s)

 -s NBSAMPLES    Number of samples

 -n NAME         Name of the test

 -d FILENAME     File to which the measured values will be logged in

4 parameters are mandatory: COMPORT MOTORS SPPEDS and CHANNELS

 * '''COMPORT''': The serial port that is connected to the MK e.g. "COM4"

 * '''MOTORS''': List of motors (comma-separated) that need to run during the test. Typically only one motor will be selected. It is also possible to activate all motors to evaluate the global vibrations before and after calibration for example. e.g. "1" or "1,2,3,4"

 * '''SPEEDS''': List of speeds at which will be tested. The "speed" is the I2C value that will be sent to controller and is a value between 0 and 255. Typically interesting values for vibration-testing vary between 100 and 200. [[BR]]There are 2 formats possible. First there is the simple list of speeds, e.g. "100,150,190,200". The second format specifies the minimum, maximum speed and step, e.g. "100-200:20" will test at 100,120,140 ... 200

 * '''CHANNELS''': List of "channels" that will be monitored. A channel is in fact one of the MK analog sensors. Measuring the pressure or battery does not make much sense in this context, but is it possible. It is my experience that channel 6 and 7 produce best vibration signals, but YMMV.

[[BR]] In addition, these optional parameters can be provided

 * '''-m MINSPEED''': The motor(s) will first be started at "idle" speed before being spooled up to the speed at which the measurement will take place. By default, this speed is 25 but it can be changed with this option. Your motors need to run smootly and start reliably at this speed. In combination with the TP converted ESC for example, the default value of 25 will be too low.

 * '''-s NBSAMPLES''': During a measurement, the FlightControl board will monitor a given channel and store 1000 samples in memory. Afterwards the VibrationTool will read these samples. These samples can be dumped in a file (see the "-d" option) and will be used to find the amplitude of the signal (the difference between the minimum and maximum measured value). [[BR]]It is important to read enough samples to cover a few periods. By default 400 samples are read but with this option, the number of samples can be modified (with a maximum of 1000).

 * '''-n NAME''': An indication of what you are testing. This string will be added to the dumps (see "-d" option) and should not contain spaces e.g. "-n AfterBalancing"

 * '''-d FILENAME''': With this option, all samples will be dumped in a text-file. This file can later be used for further analysis. It can for example be inported in MS Excel or OpenOffice Calc to make graphs of the vibration signal. When the file does not exist yet it will be created, otherwise the new data will be added. All measurements dumped in the same file should have the same number of samples (see the "-s" option) e.g. "-d motor1.txt"

 * '''-v''': With this option, the tool will be much more verbose; it will indicate what it is doing. Also when an error occurs, the tool will provide more technical details (the callstack)

== The output ==

=== The results on the screen ===

Without the "-v" option, only the results of the test is displayed:

{{{

C:\DATA\temp\VibrationTestExe>VibrationTest COM5 1 100,150 6 -n Demo

      Demo Speed=100 U=12.1V Channel=AccRoll    Min=497 Max=506 pp=  9 *

      Demo Speed=150 U=11.9V Channel=AccRoll    Min=498 Max=508 pp= 10 **

}}}

 * "'''Demo'''" This is the name of the test as we provided with the "-n" option.

 * "'''Speed=100'''" Indicates the motor speed for this measurement

 * "'''U=12.1V'''" The measured battery voltage when the measurement was done

 * "'''Channel=AccRoll'''" The measured channel

 * "'''Min=497'''" Lowest value of all samples

 * "'''Max=506'''" Highest vale of all samples

 * "'''pp=9'''" Difference between Min and Max, this is the actual result

 * "'''**'''" The number of stars gives a quick indication of the pp-value

With the "-v" option more details are provided:

{{{

C:\DATA\temp\VibrationTestExe>VibrationTest COM5 1 100,150 6 -n Demo -v

comPort  = COM5

motors   = ['1']

minSpeed = 25

speeds   = ['100', '150']

channels = ['6']

nbSamples= 400

fileName = None

testName = Demo

Opening comPort...

Version: 0.74

Voltage: 12.1V

Minimum Voltage: 10.5V

Starting motor(s) (speed=25)...  OK

Setting speed to 100 ...

Getting data...        Demo Speed=100 U=12.1V Channel=AccRoll    Min=496 Max=508 pp= 12 **

Setting speed to 150 ...

Getting data...        Demo Speed=150 U=11.9V Channel=AccRoll    Min=497 Max=508 pp= 11 **

}}}

=== The dumped signal ===

The "-d" option allows to dump the measured signal in a text-file. This is a "comma-separated" text file that can easily be imported in MS Excel or OpenOffice Calc.   

[[Anchor(DumpedSignalJpg)]]

attachment:calc.jpg

1000 samples are acoputed in about 90ms (0.09 s), the time between samples is about 0.9 ms (0.00009 s).

Suppose the prop is spinning at 5000 RPM, this means 83 rotations per second. In 0.09s we have captured 7.5 rotations. We we take 400 of the 1000 samples we should see 7.5/1000*400 = 3 rotations of the prop.

== Proposed procedure to balance prop/motor assembly ==

First we need to find what what sensor provides the "best" footage of the vibrations. The largest signal is probably the best. Candidates are Gyro and Acc signals. My experience is that AccNick (channel 7) and especially AccRoll (channel 6) provide the nicest signal, but YMMV. The vibration will typically peak at a certain motor speed. So, first we perform a sweep between speeds 100 to 200 and look at channels 6 and 7 and choose a channel and speed we will concentrate on.

Next I check if the prop can be balanced a bit better. I stick small strips of tape to the prop, close to the center. One strip to the side where the prop-dimension is mentioned I denote as "-1", one strip on the other side, I denote "+1". I test different configurations and check what gives the best results for my chosen channel and speed.

Now that the prop is better balanced, I start to rotate the prop in relation to the motor. As names for the test I use "XsA" where "X" is the number of strips and "A" is the angle; e.g. "+1s60" means 2 strips (opposite to the prop-marking) and rotated by 60 degrees (compared to the starting position). Again I try to find the best position.

Once we have found the best rotation, we can rebalance the prop in the same way as before.

After all this we should have found the best combination. We can perform the swipe again to compare with the starting point.

=== Example 1 ===

This is an example with standard Roxxy 2824-34 motor with EPP 1045 prop.

[[BR]] 

Finding what sensor provides best information at what speed:

{{{

VibrationTest.py COM5 3 100-200:20 6,7

      Speed=100 U=11.3V Channel=AccRoll    Min=492 Max=505 pp= 13 **

      Speed=100 U=11.3V Channel=AccNick    Min=498 Max=507 pp=  9 *

      Speed=120 U=11.3V Channel=AccRoll    Min=489 Max=503 pp= 14 **

      Speed=120 U=11.3V Channel=AccNick    Min=497 Max=507 pp= 10 **

      Speed=140 U=11.2V Channel=AccRoll    Min=469 Max=519 pp= 50 **********        <<=======

      Speed=140 U=11.2V Channel=AccNick    Min=495 Max=508 pp= 13 **

      Speed=160 U=11.1V Channel=AccRoll    Min=478 Max=517 pp= 39 *******

      Speed=160 U=11.1V Channel=AccNick    Min=493 Max=511 pp= 18 ***

      Speed=180 U=10.9V Channel=AccRoll    Min=479 Max=511 pp= 32 ******

      Speed=180 U=10.9V Channel=AccNick    Min=493 Max=514 pp= 21 ****

      Speed=200 U=10.7V Channel=AccRoll    Min=479 Max=515 pp= 36 *******

      Speed=200 U=10.7V Channel=AccNick    Min=493 Max=513 pp= 20 ****

VibrationTest.py COM5 3 130-160:10 6

      Speed=130 U=11.1V Channel=AccRoll    Min=484 Max=511 pp= 27 *****

      Speed=140 U=11.1V Channel=AccRoll    Min=469 Max=524 pp= 55 ***********

      Speed=150 U=11.1V Channel=AccRoll    Min=475 Max=520 pp= 45 *********

      Speed=160 U=11.1V Channel=AccRoll    Min=479 Max=518 pp= 39 *******

}}}

So, lets concentrate on channel 6 (AccRoll) at speed 140.

Now, the preliminary balancing of the prop:

{{{

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 0s0

  0s0 Speed=140 U=11.0V Channel=AccRoll    Min=470 Max=521 pp= 51 **********

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 1s0

  1s0 Speed=140 U=11.0V Channel=AccRoll    Min=482 Max=513 pp= 31 ******

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 2s0

  2s0 Speed=140 U=11.0V Channel=AccRoll    Min=475 Max=520 pp= 45 *********

}}}

For now, 1 strip seems best.

Now, lets rotate the prop:

{{{

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 1s0

  1s0 Speed=140 U=10.9V Channel=AccRoll    Min=481 Max=513 pp= 32 ******

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 1s60

 1s60 Speed=140 U=10.9V Channel=AccRoll    Min=480 Max=512 pp= 32 ******

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 1s120

1s120 Speed=140 U=10.9V Channel=AccRoll    Min=477 Max=514 pp= 37 *******

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 1s180

1s180 Speed=140 U=10.9V Channel=AccRoll    Min=482 Max=509 pp= 27 *****

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 1s240

1s240 Speed=140 U=10.9V Channel=AccRoll    Min=482 Max=510 pp= 28 *****

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 1s300

1s300 Speed=140 U=10.9V Channel=AccRoll    Min=482 Max=514 pp= 32 ******

VibrationTest.py COM5 3 140 6,6,6 -d motor3.txt -n 1s360

1s360 Speed=140 U=10.9V Channel=AccRoll    Min=482 Max=515 pp= 33 ******

}}}

Rotating the prop by 180 degrees produces best results, now lets try to balance the prop again:

{{{

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 1s180

1s180 Speed=140 U=10.9V Channel=AccRoll    Min=483 Max=509 pp= 26 *****

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 0s180

0s180 Speed=140 U=10.9V Channel=AccRoll    Min=472 Max=519 pp= 47 *********

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 1s180

1s180 Speed=140 U=10.9V Channel=AccRoll    Min=483 Max=510 pp= 27 *****

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 2s180

2s180 Speed=140 U=10.9V Channel=AccRoll    Min=489 Max=508 pp= 19 ***

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 3s180

3s180 Speed=140 U=10.9V Channel=AccRoll    Min=483 Max=512 pp= 29 *****

}}}

So, 2 stickers is best, let's verify again:

{{{

VibrationTest.py COM5 3 140 6 -d motor3.txt -n 2s180

2s180 Speed=140 U=10.9V Channel=AccRoll    Min=488 Max=508 pp= 20 ****

VibrationTest.py COM5 3 140 6 -d motor3.txt -n end

  end Speed=140 U=10.8V Channel=AccRoll    Min=487 Max=510 pp= 23 ****

}}}

[[BR]]

Now, we can perform a sweep in order to compare with the starting-point:

{{{

VibrationTest.py COM5 3 100-200:20 6,7

       Speed=100 U=11.1V Channel=AccRoll    Min=493 Max=501 pp=  8 *

       Speed=100 U=11.1V Channel=AccNick    Min=499 Max=507 pp=  8 *

       Speed=120 U=11.1V Channel=AccRoll    Min=489 Max=507 pp= 18 ***

       Speed=120 U=11.1V Channel=AccNick    Min=497 Max=508 pp= 11 **

       Speed=140 U=11.0V Channel=AccRoll    Min=489 Max=507 pp= 18 ***

       Speed=140 U=11.0V Channel=AccNick    Min=498 Max=509 pp= 11 **

       Speed=160 U=10.9V Channel=AccRoll    Min=482 Max=508 pp= 26 *****