Maestro A2100-B Manual de usuario descargar pdf (Pagina 7)

for powering the motors and the perf board. There are two

DC brushless motors with electronic speed controllers that

will be directly hooked up to the batteries. These will take up

most of the current given off by the batteries and power the

blimp so it can move. The other components will be powered

by the second output from those same batteries.

The perf board will be responsible for powering all of the

units on the blimp minus the camera and the aforementioned

motors and speed controllers. It will have two batteries

connected to it that will power the 3 servo motors, the

transmitter and all the PCB components. The two batteries

will implement two 5 volt voltage sources which will be

regulated and dispersed to the correct components. There will

also be a 3.3 volt regulator which will regulate voltage to all

the components that use 3.3 volts instead of 5 volts. The perf

board will nested alongside the PCB inside the gondola.

F. Power System - Groundstation

The power system of the ground station was determined

by the need of a 5V and 3.3V rail. The power consumption

from the transceiver, the CP2102 (UART to USB) module,

and the PIC18F2620 required these fails and the current draw

from it was very low (around 200mA at most). We decided

to use linear voltage regulars to and a outlet adapter which

supplies the initial 9V to step down to 5V and 3.3V. The

voltage regulator we use to step 9V to 5V is the LM2940C-5.0

which can handle inputs from 7V to 26V and steps it down to

5V. Then we cascade the LM2940 with a LM3940 which steps

down the 5V to the 3.3V we need for the transceiver module.

We put a 22uF capacitor on the input of the voltage regulars

and a 46uF capacitor on the output of the voltage regulators

to smooth out the power input and the LM2940 actually won’t

work without capacitors of speciﬁc values on it. We chose the

linear voltage regulators over the switching regulators because

the circuit design of the switching regulator was too complex

to put on the perf board and took too much area and the

current draw on the components wasn’t high enough to where

we would generate a lot of heat on the voltage regulators (we

never max out the 1 amp limit on the voltage regulators).

IV. TESTING

Testing for the controller occurred on the Arduino Uno

development board. The Arduino Uno is powered by a USB

to SPI connector and has the Atmega328P, which is in the

MASS blimp. The Uno was used to write and test code that

was eventually used in the ﬁnal version of the blimp. Most

of the functions in the blimps programming used the open

source Arduino libraries. Code developed to control all of the

various aspects of the blimp system. In order to get signals

to the blimp, the blimps program needed a plethora of serial

communication inputs. The ﬁnal blimp needs to use three

different methods of serial communication, I2C, SPI, and

UART for input data from the various modules. The program

HyperTerminal was downloaded to test reading input and

output data to and from the microcontroller board.

Testing the various servo motors was done by inputting

incrementing duty cycle percentages into the motors. This

program design layout did eventually end up into the blimp’s

ﬁnal programming. The ﬁnal blimp will feature a remote

control that will allow the user to speed up or slow down

the blimp as well turn the camera or the blimp itself. To test

the camera stabilization system, the Arduino board had to

get serial data from HyperTerminal. The user would input

a button press which correspond to an increment in the

percentage of the duty cycle of the Pulse Wave that servo

motors read in for controls. Through testing and various

speciﬁcations from group members the code was developed

to eventually completion.

The testing for the motors involved researching the electronic

speed controllers and learning the quirks of the motor. There

was very little information no how to control the motors

without a direct link to the RC Transmitter/ controller.

Testing needed to be done to ﬁgure out how a microcontroller

could emulate the signal sent by those kinds of controllers.

By testing various duty cycle percentages and ﬁnding out

the proper arming sequence, the motors were able to be

controlled very well. The testing found that the motors did

not work with a duty cycle of less than 50%. To compensate

for this the group tested out differing sizes of propellers as

well as different motor sizes. Testing for the blimp’s turning

system was done by continuously changing how the duty

cycles on the blimp blimps two brushless motors. Eventually

the group members decided on an economical approach on

how to implement turning in the blimp. The decision was

to read in the command that the user wanted to put in, left

or right, and then a function would be called that would

implement turning the blimp. The blimp turns by simply

slowing down the opposite motor. For example, to turn right,

the right motor will lose up 30% of duty cycle relative to the

left motor. This difference in motion will cause the blimp to

turn. The reduced speed of the motor will in theory last for

up to 3 seconds.

Testing the GPS module was only possible after the

ﬁnal PCB was in, due to that fact that the funds needed for

another GPS module and the breakout board needed to test it

were unavailable to the group. Testing was done by sending

the serial data from a terminal to a USB to UART module.

To test the IMU, I2C serial communication needed to be

implemented. This required testing on the Arduino Board

to fully integrate the gyroscope and accelerometer data into

the blimps microcontroller. Testing the SPI was needed to

receive controls from the ground station and ultimately from

the user. Testing and writing the code to implement the serial

communication was done on the Arduino Uno development

board.

Testing the transceiver unit for the blimp and connection

to the computer GUI happened separately from the blimp

but ultimately it will all be tested together. the transceiver

unit test was created by a mock blimp receiver unit to

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