Delhi undergrads bag Rs.73,272 with unmanned aircrafthttp://www.eetindia.co.in/ART_8800581782_1800001_NT_67ad6fb0.HTMA team of 10 second-year undergraduate students from various branches of Delhi College of Engineering (DCE) have won Rs.73,272.20 ($1,500) and Director's award for the best team effort for demonstrating a successful flight of an unmanned aerial vehicle (UAV) at the 2009 Association of Unmanned Vehicles System International (AUVSI) Student Unmanned Aircraft System (UAS) competition.
The 2009 Team DCE UAS, guided by professor P.B. Sharma (also the director of the institute), assistant professor D.S. Nagesh and lecturer N.S. Raghava, developed a fixed-wing UAV.
The aircraft used Sig Rascal 110.
Inside the UAV
The UAV has a basic inertial measurement unit from Crossbow Inc., which is responsible for the measurement of the angular rate of turn, accelerations and the magnetic field strength along the thee axes, explained team captain Rochak Chadha. The UAV integrates a GPS along with dynamic and static pressure sensors to determine airspeed and altitude, respectively. āThe magnetometers on this unit were not working perfectly, so we purchased another three-axis magneto from PNI Corp.,ā said Chadha.
The data from the sensors reports to a single board computer (SBC) by Technologic Systems running Linux on an ARM 9 processor at 500MHz over an RS-232 link.
The SBC has a six-state extended Kalman filter for computing the roll, pitch and yaw as well as the position, speed and altitude of the UAV, delivering at 50Hz. The SBC sends the data to the ground station over a wireless RS-232 Link at 9,600bps using a Maxstream Xtend RF modem.
The SBC also runs a control algorithm to determine necessary action to bring the aircraft to the steady-state flight condition as well as maintain it on the flight path irrespective of winds or any other disturbance. "The SBC is the brain behind the UAV," Chadha said.
Meanwhile, the imaging system is independent of the SBC. The camera is directly connected to the analogue video downlink system.
āThe team used Eagle CAD for PCB design, specifically for power distribution on the boards,ā said Chadha, āas well as Matlab and Simulink for the design of UAV control system and automatic target recognition system (image processing tool-box).ā
According to computer engineer Arjit Arora, the aim of the project is to develop a UAV with maximum in-house components in order to reduce cost and cut dependence on imported products. He said that one of the most important components of the UAV is an autopilot.
Arora said that a commercial off-the-shelf autopilot is very expensive, varying from Rs.4 lakh for the basic one to Rs.8 lakh for a better version. "Since we have been developing our own autopilot, the cost has been substantially brought down to Rs.1 lakh - Rs.1.5 lakh," he claimed. He added that the software architecture was designed in a way that would allow it to be easily used for all kinds of aircrafts with some slight programming changes.
A small freedom base was built to test the attitude heading and reference system.
"An important feature of our Indigenous Autopilot Program is that we developed the autopilot for that particular aircraft," Chadha said. He explained that all the commercially available autopilots are adjusted by the teams to suit their particular airplane. The team first modelled the aircraft in Simulink and studied its open loop behaviour and based on that designed the autopilot.
The winning team used a commercial autopilot, according to Chadha, while the DCE team designed their own. He believed that one of the major reasons behind the winner's success was that they had many flights and had configured their systems well. "Also, since their autpilots were commercial products, they had everything fitted in a nice and compact manner. We had our various modules working on different boards. So, systems integration in one part where we will improve on this year along with the miniaturisation of our entire autopilot system."
Different goals
Commenting on how the DCE team faired with the competition, Chadha cited experience as a key factor. "The top teams have been participating in the competition in the past years,ā he said. āAlso, there was a difference in their goals. The other teams were aiming to meet the objectives of the competition rather than develop low-cost UAVs.ā
According to Arora, funding of the project was not entirely smooth. He said that working with a tight budget, costs had to be reduced by a big margin over their initial estimate. The college has fully supported and funded the development of the vehicle, and the Department of Science and Technology sponsored the travel expenses. "However, we are looking for a long-term sponsor as the implications of this project can be pretty big. The team is hopeful for a much more positive response from the private sector this year for the further development of the UAV so that it can reach the stage of market readiness," he said.
Chadha: We intend to work on making our system more safe and reliable.
The team now plans to focus mainly on testing and optimisation. "With design work mainly done, we hope to improve our software systems with every flight. System integration will also be a priority since it was one of our major shortcomings. We intend to work on making our system more safe and reliable with the addition of features in the autopilot and ground station," Chadha said.
Industry leaders like Northrop Grumman, IBM, Boeing and Lockheed Martin sponsored the 2009 AUVSI, held from June 17-21, 2009 in Webster Field, Maryland, United States. Most of the teams comprised Ph.D students and undergraduate students working with them.