RC Control Spring 2016

Posted by: Luis Valdivia(Project Manager)
Written by: Kevin Nguyen(Electronics and Controls)

 

Table of Contents:
– Introduction
– Transmitter and Receiver
– Setting up the MultiWii
– MultiWii GUI
– Arming and Disarming

 

Introduction:
Being able to use the RC controller early on in this project will be very beneficial since it will make testing safer and more efficient. Since EDF’s spin at very high rpms, it is not a good idea to keep your hands on the quadcopter while testing. The RC controller will allow you to test the quadcopter at a safe distance. An added benefit to using the RC controller is that it doesn’t add that much weight to your system. All that is needed for the quad to communicate with the controller is the receiver. This blog will guide you through setting up RC control.

 

Transmitter and Receiver:
The RC controller that we used is the HK-T4A V2. This comes with a transmitter and a receiver. Most likely, you will be using the same controller as us so they would already be binded, but if not, follow this video to bind your devices. The transmitter will be from the remote controller. It will send a 2.4Ghz signal to the receiver on the MultiWii. The RC signal is much more reliable than bluetooth and is capable of transmitting at much further distances.
The transmitter controls the throttle, yaw, pitch, and roll of the quadcopter. The left joystick controls the throttle and the yaw; Vertical direction controls the throttle, horizontal direction controls the yaw. The right joystick controls the pitch and the roll; Vertical direction controls the pitch, horizontal direction controls the roll.

rc controller

 

Fig 1.1 RC Controller

The receiver is connected to the MultiWii. Each channel on the receiver corresponds to a command on the controller. The transmitter sends out signals in the form of radio waves and the receiver converts those signals to electrical signals for the MultiWii to read. The connections on the receiver must be connected to the appropriate pins on the MultiWii in order to control it properly. Refer to this blogpost for MultiWii connections.

rc receiver

Fig 1.2 HK-T4A Receiver

Setting up the MultiWii:

To set up the MultiWii to be compatible with your quad, you need to download the MultiWii source code here. After getting the source code, go into the config.h file and select the appropriate configurations based on your project. To select an option, simply remove the comments(//).

For our project, we used:
#define QUADX
#define MINTHROTTLE 1150
#define MAXTHROTTLE 2000
#define I2C_SPEED 400000L
#define INTERNAL_I2C_PULLUPS
#define FREEIMUv035_BMP

Copy and paste this anywhere into the config.h file:
#define MAG_ORIENTATION(X, Y, Z) {magADC[ROLL] = -Y; magADC[PITCH] = X; magADC[YAW] = Z;}

Some things to mention are that the minthrottle should be kept as is. The quadcopter needs to be under a certain throttle to arm and if the minthrottle is set too high it won’t reach that arming point. Another thing is that for the board options, the MultiWii isn’t listed there, using FREEIMUv035_BMP would work as well.

MultiWii GUI:
The zip download for the source code included a GUI as well. The gui can be used to change the PID settings and calibrate the sensors. The GUI only monitors the sensors, you can’t control the device through it.

Arming and Disarming:
The most important commands for controlling the quadcopter is arming and disarming. Arming connects transmitter and receiver so that you can begin communication. Disarming disconnects the communication. If it flies out of control during testing, you can disarm to stop the motors from spinning. Typically, to arm you pull the throttle down and yaw to the right. To disarm you pull the throttle down and yaw to the left. This is convenient since you can arm and disarm with one joystick. The arming and disarming commands can be changed in the config.h file.

Works Cited:
https://www.youtube.com/watch?v=JyAyM1f_O3Q
http://www.arxterra.com/multiwii-esc-and-receiver-connections/
http://dl.btc.pl/kamami_wa/hk_27033_2.pdf

 

 

Spring 2016 AdBot Critical Design Review

The Rover should travel on level area, ramp area, and stair ways during the mission test.

Critical Design Review

By Dang Le, Project Manager

  • Dang Le (Project Manager)
  • Don Tran (System Engineer)
  • Muhammad Ali Siddiqui (Electronic Engineer)
  • Muhammad Maqbool (Manufacturing Engineer)

Executive Summary

Program Objective/Mission Profile

Program Objective

The project objective is to build a rover that will simulate a flyer distributor advertising CSULB’s Eta Kappa Nu social, guest speaker, and technical events on campus. Using a single power source the rover will launch from, and return to, an HKN advertisement booth and run in a general high foot-traffic area on campus which consists of flat areas, sloping areas, and stair ways, as shown in the course map. The rover will be controlled remotely using a computer with internet connection. Negotiations of budget resulted in the rover to cost less than or equal to $250. There is to be expected 0 to 16 mph wind during the course run on May 13th (Reported in Weather Report).

Mission Profile

The total distance is approximated in 344fts. The perimeter of the grass is 275 ft / 84 m. The north and south sides are leveled. The east side has 9 steps. The west end is a ramp.

Mission-CDR-72dpi

The front of USU building

The Design

The main component in our rover design are including

  • Four drive motors (2 on the front and 2 on the back).
  • One gearbox motor (for the center).
  • Six wheels and tracks.
  • Two arms with supported by horizontal shaft and gear.
  • Pole holder for advertising and smart phone.

Adbotexplosive-72dpi

Project Features

  • Rover with advertising sign will be traveled up stairs and slope area in front of USU building.
  • Rover will be run and return to HKN advertisement booth in a single charge.
  • One shaft  with high torque gear box motor to support the lifting arms weight during the stair climbing.
  • Operator will be controlled remotely using Arxterra application with computer wifi connection.
  • Innovative wheels design to have a better track grip.
  • New aerodynamic body design to reduce weight and wind resistance

Custom PCB Design

Fritzing diagram circuit with three H-bridge and I2C protocol IC to drive five motors with using Arduino and firmware coding.

CDR-Frizing-72dpi

Fritzing Diagram

 

Custom-PCB-72dpi

Breadboard testing transmit and received data with using H-bridge IC circuit and Arduino coding.

 

PCB layout

PCBlayout-CDR-72dpi

 

Hardware Design

By Muhammad Maqbool, Manufacturing Engineer

The body of our AdBot is set to be 12” x 8” x 2”. The Body is made of Aluminum. I got separate sheets of Aluminum each with a thickness of 0.125 inch and I welded them together with the help Ryland Walts. The reason for choosing Aluminum is that for our AdBot we wanted a strong body that would not get damaged if our AdBot hits the stairs or anyone try to kick it.

The body consist of two holes in the back each of a diameter of 0.16 inches, the holes provide a path for the driving motors to directly connect with the wheel. The two holes in the front of the body provides a path for the shaft to pass through and will be connected to the free moving wheels and arms.

The wheels are printed using ABS plastic. ABS plastic is the most cost effective material. Each Wheel has a diameter of 2.5 inches and a thickness of 0.7 inch. The arms of the our AdBot will be of Aluminum as wheel, the arms will be 6” x 1” with a thickness of 0.125 inch. We have two motors in the front of the arm that will be driving the front wheels at all times. I have designed the gear for the shaft and the motor myself. As the motor rotates the gear on it rotates with it hence rotating the gear on the shaft and lifting the arms. I have designed two arm holder myself that will hold the arm on the shaft at all times.

The top of our AdBot is more aerodynamic by adding curves to it so it can go fast. The top is 12” x 8” and will sit on the body and I will screw them both. I will design a pole holder that will hold our pole hence holding our sign.

Adbot-topview-72dpi

top-CDR-72dpi Demension-CDR-72dpi

Software Design

Test code for controlling motors with Arxterra Application

SW-CDR-72dpi

SW-master-Slave-CDR

 

Project Update

By Dang Le, Project Manager

Work Breakdown Structure (WBS)

As a project manager, who created and assigned tasks for each member within the team throughout the project. A work breakdown structure (WBS) that showed each of team member who had responsible for their tasks. There could be a change during the mission task depend who has more free time and ability to take workload from other member. Here is our delegation tasks that showed in display below.

WBS-CDR-72dpi

Budget Report updated

As a Project manager, I have to keep track on our budget to make sure it still within our given budget. The most expense is on prototype component and chassis. Unfortunately, our rover were bigger compare to previous semester, thus we have to look for the difference type of tracks that can support our rover during the mission test course. First, we thought we could use 6V DC motor for our rover ( these motor are free from previous semester), but now due to the rover is too heavy and may not be able to travel on stair ways and long distance, so we may replaced with 12V DC motor for final demo. Our budget report with expected cost right now without five of 12 V DC motors is $220.44.

Cost-report-CDR-72dpi

 

Schedule Updated

Project schedule is the software that used to create a task schedule and plan in this project for a specific date to be completed. As the project moved on, we could see which tasks we were completed or behind the schedule. The schedule showed in green check mark that indicated these tasks were completed. However, the main concern was the PCB schematic and PCB wiring layout. We have built a new schematic, which more complicated than our thought due to more parts on PCB and not enough clearance between one trace to another, thus our team member were having so much trouble when doing the layout. Furthermore, we were down by one of our team member electronic engineer. Thus, we were behind the schedule as our planned. Another issue was main tracks for our rover. The current track we have as the same last semester that was not support enough for our rover during the mission test. We are still looking for the tank track and 12 V DC motor with high torque for our AdBot.

ProjectSchedule1-CDR-72dpi ProjectSchedule2-CDR-72dpi

 

Status and Percent Complete

Here is the status and percent burn down  as we move along until this time. The charts showed that we were behind on software coding, PCB layout, and hardware as well.

PercentcompleteCDR-72dpi BurnDownCDR-72dpi

Project Demonstrations

click the link below to watch the AdBot demonstration

https://www.youtube.com/watch?v=CX5fDNFeUjc

 

 

Spring 2016 Additional Fan Bracket Design

Posted by: Luis Valdivia (Project Manager)
Written by: Juan Mendez (Manufacturing Engineer)

Table of Contents:
Introduction
Design
Conclusion

Introduction:
Since weight became an issue with our vehicle, we had to think of an alternative solution to fix the yaw problem. Our alternative solution was to add an additional brushless fan to counter the yaw problem. In order to add on another fan we needed to find a way to mount it on to the current frame. We thought of drilling new holes on to the frame to add on to the bracket, but instead of making new holes, we decided to use the ones that were already on the frame. In order to put the fan between two of the ducted fans, I had to use the holes that were between two of the current metal brackets. I modeled the bracket to be 1.67 by .31 inches as shown in Figure 1 so that they can fit perfectly between two ducted fans.

Figure 1 Demonstrating dimensions of 5th fanbracket

5thfanbracket

Design:

I wanted to make sure that the bracket would enclose the bracket provided by the brushless fan so I made the bracket extend approximately 1.25 inches as shown in Figure 1.
After measuring the bracket that came with with brushless fan, we saw that it was 3.4 by 3.4 mm thick. This is equivalent to .13 inches. In order to make sure that the brushless fan bracket could fit into mine, I made the inner cut of .14 by .14 inches so it can slip in smoothly as shown in Figure 2A. In order to make sure that the 3D printer could print the part without having it warp, I had to make the outer dimensions be .33 by .34 inches thick as shown in Figure 2B. This allowed the part to be printed without any trouble.

Figure 2A and Figure 2B Demonstrating dimensions of bracket design

bracket design

Conclusion:

The result were the parts fabricated shown below in Figure 3 A & B. The brackets were able to mount on smoothly into the brushless fans with no problem. They were then easily mounted on between the ducted fans on the vehicle as seen in Figure 4. Additional brackets were fabricated incase we needed to add a 6th fan to fix the yaw problem.

Figure 3A and Figure 3B alternate angles of 3D printed brackets

printed piece

Figure 4 5th fan attached to 3D printed bracket

attached