How I got Involved with Research

After volunteering in the Applied Robotics Lab last summer, I noticed that robotics was a viable academic interest for me. I added getting a graduate degree in robotics to my future goals. Before I applied to a good graduate school, however, I knew that I needed to perform some research related activities while getting my undergraduate degree. With these thoughts in my head I walked into Dr. Cook’s office during the fall semester of 2013. Dr. Cook is a very experienced professor whose experiences and interests fall under robotics and control systems. With him, we talked about my interests and his experiences and came up with a project about Unmanned Aerial Vehicles. Initially I worked on the project from my house but after spring break I moved to Lofaro Labs, the new robotics lab in the engineering building. Dr. Lofaro, director of the lab, has also helped me by suggesting additions to the project.

On a weekly basis I set up goals for myself and I try to complete them before the week ends. To give back to the community I have also recruited a high school student, Mustafa Bal, to help me during this project. We usually get together on Saturdays and work on the project together. Currently it seems like he is convinced in getting an undergraduate degree in Engineering. Last week I spent more than 20 hours to make an addition to my current project. I printed plastic micro arms using my friend’s 3d printer and I configured my onboard computer to control the arms. Using visual servoing techniques I made the arms point towards a green apple. I have also put up a page in my website talking about this project (http://www.magcayazi.lofarolabs.com/mmuavarm.html). The experiences that I gained while working on this project have helped me further define my interests in robotics. 

Detecting Obstacles using a Single Camera for Micro Air Vehicles

     Research laboratories continuously work to find new algorithms and instruments that will enable Micro Air Vehicles (MAVs) to detect obstacles when they are flying autonomously. Since the payload capacity for these aerial vehicles are limited, carrying depth sensors or mounting a stereo vision system is not the most efficient way to detect obstacles. A single camera is lightweight and gives very important information about the device's surroundings. This is why some scientists are trying to find algorithms to detect obstacles using a single camera.
     Recently scientists have tried using Optical Flow to detect obstacles and avoid them. Optical flow is an algorithm that finds the changes in different frames. One way to calculate the flow or the change between different frames is to use edge detection to find points of interest. The computer algorithm continuously does this and tracks where the edge, or the point of interest, has traveled to in the next frame. In my video below you can see how the algorithm tracks some points of interest on a ball.

Using the same concept researchers are writing algorithms to track if the object of interest is moving towards the MAV relative to MAV's camera. If this occurs than the MAV moves towards the side where optical flow occurs less rapidly. In a masters project at Land University Cognitive Science, Emil Gunnarson showed his algorithm to avoid obstacles using optical flow. You can see how the algorithm performs in the video below.

One of the biggest disadvantages of this algorithm is the fact that when the obstacle is right in front of the MAV, the algorithm cannot detect it because it is not moving to either side. The only obvious thing about an obstacle right in front of the MAV is that it is getting bigger as the MAV approaches it.
Tomoyuki Mori and Sebastian Scherer (Robotics Institute, Carnegie Mellon University) have done a study to detect obstacles which are right in front of the MAV using a single camera. Their algorithm detects objects that are getting larger and interprets this as an incoming obstacle. Their paper is available freely on the Carnegie Mellon's website. From their initial results it seems like they were successful in determining obstacle positions and avoiding them with a Quad Copter. In the video below you can see their results.


These two algorithm's could be combined but I am not sure about how much computing power that would require. Adding a system that would turn the camera to the direction of the MAV would also make these two systems a lot better. This way the MAV could use all 6 Degrees Of freedom to move instead of just one.

Vogenau School of Engineering Celebration of Undergraduate Research

     On April the 24th Volgenau School of Engineering (VSE) held its first annual Celebration of Undergraduate Research Poster Session. A total of 39 posters were presented by many undergraduate students and more than 100 guests attended the evening at the Mason Inn. In my second year at Mason (2012 - 2013) I was really eager to collaborate in a research project. I emailed a lot of professors in my department about being a part of a project without any luck. I was disappointed then without knowing the difference of emailing a professor and meeting in person (In one year I tried the same thing but this time I arranged a meeting with my professor and I started a new project).
     I must say that the VSE as an engineering school did not fully encourage their undergraduate students to contribute in research activities. However, with the beginning of events where students can present their research activities, VSE has demonstrated the fact that they now understand the importance of undergraduate research. I was also at the evening as a presenter. At the evening I was mainly surprised to see many professors and department chairmen from the Engineering school. I think their support will help make the following events more successful.

A frame from the poster session from the VSE website

I would now like to talk about the project that won two awards at the evening. The name of the project is The Automatic Piano Tuner. One of the reasons why this project was successful is that the title explained most of what the project was about. The motivation behind the project was the nonexistence of an accessible automated piano tuner. The presenters (Lakshmi Meyyappan, Sara Bondi, Fritz Reese, and Jacob Morgan) were also very successful at presenting their project.

All in all I believe that these events will help promote undergraduate students to be involved in hands on work that combines what they learn with an application. This makes the learning process to become very through and makes a theory into an experience for students. I would like to end with expressing the importance of having an Undergraduate Research Journal where successful students can publish their articles. The beginning of an annual Celebration of Undergraduate Research has shown again the tradition of innovation within the George Mason community. We should continue this tradition with starting a new journal where undergraduate engineers can publish their articles.

Tell me about what you think. Would a new journal be good for VSE students?

-Talha

A Revolutionary Stabilization Technique for MAVs

      As I have said in my first post, MAVs need flight controllers to stabilize them in flight. These flight controllers have complex algorithm's that run recursively. Usually these systems only take advantage of the four propellers to stabilize the system. Until one of my professors showed me a blog post about a new stabilization technique for MAVs, I also thought using propellers was the only way to stabilize MAVs.

    Like insects, this new system changes the center of mass of the system to stabilize the craft. This technique was developed by a team in the LIMBS Laboratory of Johns Hopkins University. The team of researchers who came up with this system, first examined how moths stabilize in flight. below is a video showing how a moth uses his moth to move the center of mass to have a stable flight. 

     Researchers used the same idea to stabilize a quad copter. To make an abdomen that has enough mass for the quad copters, the team of graduate students made a gimbal for the battery. Below is a picture of how the final design looked like.

Notice the battery attached with a servo below the copter. Credit Alican Demir.

With the battery being placed on a servo, the group of researchers were able to stabilize the quad rapidly. A video of the final design is in this blog. After I noticed this new technique for stabilizing in flight, I realized that many more MAVs will begin to have this technology. 

More to add later. 

A Brief History of Quad-rotors and an Introduction to Flight Controllers

        Welcome to my blog! In this blog I am going to share interesting research on the development of Micro Air Vehicles (MAVs). I myself am also doing some design and research on MAVs therefore in the future I will also post about my own design and research results.
In my first post I will be briefly talking about the history of quad-copters (from the family of MAVs). I will end with talking about the flight controller that I use.

De Bothezat Helicopter, Edison National Historic Site Archives

      Although most quad-rotors we see today are unmanned, there was a time when these copters were designed specifically for human use. After the first airplane design was successful, the government allocated some money on vehicles that could take off and land vertically. George de Bothezat received funding for his design in the early 1920s. A picture of the built design is show on the right. Quad copters are 6 degree of freedom systems. Although the De Bothezat helicopter flew in 1922, the government shut down the program because it was really difficult to control a quad copter. In the beginning of the video below you can see a De Bothezat Helicopter flying.

As you can see, the De bothezat helicopter is not very stable and it keeps on turning counter clockwise around it's z axis. Today, two of the propellers, in every quad copter, turn in the opposite direction to keep the craft stable. If all four turn the same way, then the forces would add up turning the whole copter. Below is a picture that shows the direction of the propellers on a quad copter.

Ardpilot.com

Since the size of electronics have become smaller we can now mount flight controllers on top of small quad copters. These flight controllers solve the difficult stabilization equations and make it easier for us to control the quads. This article gives a very good introduction on flight controllers. It shows the different flight controllers that are available and their advantages.

Ardupilot.com

    For my design I chose to use the arducopter flight controller. The ardupilot flight controller is an open source board that has a very active developer community. This developer community fixes bugs with the current firmware, adds new features and releases the new firmware. The ground station Graphical User Interface (GUI) also gets updates and looks very modern and runs fairly fast. A picture of the ardupilot board is shown on the right. Some of the features of the flight controller is listed below.

1. Arduino compatible with an integrated Atmega chip.
2. 3 axis gyro and accelerometer
3. Barometer to sense the altitude 
4. 4 Mb datachip on board to log flight details
5. GPS and telemetry inputs. 

On one of my next posts I plan to explain the GUI and its features.