2008

2008 Team

The South Dakota School of Mines and Technology Unmanned Aerial Vehicle team (SDSM&T UAV) has devised a two vehicle system capable of completing the mission in the allotted time of 15 minutes. The two vehicle concept is a result of extensive analysis of the team�s previous five vehicle concept. Advances in controller capabilities now allow two vehicles to accomplish the mission more efficiently while providing a more elegant, simple, and adaptable solution to the problem.

The system uses a helicopter to fly the three kilometer flight path and then search the structures for a symbol. The helicopter is capable of traveling the three kilometers in under four minutes. The secondary vehicle, called the Structure Entry and Reconnaissance Vehicle (SERV), is transported to the structure by the helicopter. The SERV is deployed from the undercarriage of the helicopter after the target opening has been identified. It is designed to enter the building through the opening and search the interior of the building for a target. Video is sent to and recorded by the main vehicle�s onboard computer and simultaneously streamed back to the base station in compressed form. The SERV will continue to search the building until its onboard power has been depleted. The helicopter will return to a designated GPS waypoint after the SERV has been deployed.

Main Vehicle

The main vehicle team�s focus is to design an aerial vehicle that can negotiate a 3 km course of GPS waypoints. The vehicle also has to carry the SERV (Structure Entry and Reconnaissance Vehicle) and communications systems to the designated town. Once the helicopter has used its onboard camera and laser range finder to locate an open window on the designated building, the helicopter must then deploy the SERV. After deployment, the SERV enters the open window and reports media back to the base station.

The SDSMT UAV team has completely redesigned the system for the 2007 and 2008 competiton years. The new system uses an Airstar International Mongoose airframe which gives the team sufficient flight time and payload for a fraction of the previous system cost. The main helicpoter functioned extremely well at competiton. During the 2007 International Aerial Robotics Competition, it sucessfully located the building marked by the IARC symbol and found an open window on the building.

Hardware and Software Utilized on the UAV

The main helicopter uses specialized hardware for guidance and navigation. Autonomous flight is achieved via the combination of the Rotomotion Automatic Flight Control System hardware (AFCS) and SDSM&T�s custom Mission Control System software (MCS). These two systems in combination allow the flight crew to design and execute pre-programmed waypoint paths, monitor mission-specific intelligent control software, and maintain full control of the vehicle at all times.

The AFCS performs the attitude and position control of the UAV. It maintains the stability of the helicopter in hover and translational flight. The UAV will perform an autonomous translational maneuver only when the AFCS is sent a waypoint from the MCS. The AFCS computer can store and execute a way-point stack, allowing the helicopter to follow a pre-programmed course even if it is outside of radio range or line-of-sight.

The Rotomotion AFCS consists of an embedded computer running Linux, a WAAS-enabled GPS unit, three accelerometers, three gyroscopes, and a three-axis magnetometer. It utilizes PID controllers to maintain attitude and altitude in translational flight and hover as well as flight during a fast forward flight mode. The GPS unit is primarily used to maintain course and speed as well as fixed hovering positions.

Sub Vehicle - SERV

Following the previous year's competition milestones, the team has taken its design of the Structure Entry Reconnaissance Vehicle (SERV) to a new level. An improved airframe has been developed to reduce weight, increase flight durability, and improve operational safety. The SERV uses two 2000mAh 11.1v Lithium Polymer batteries wired in parallel along with four AXI 2212-34 brushless motor with two-bladed APC 10x4.7 props. The airframe is configured in the X configuration. Sensors include a MEMSense nIMU inertial measurement unit, a Mobisense Systems CMOS camera, and a Hokuyo scanning laser range finder. This data is then fed into the Gumstix Overo Fire onboard computer.

An extended Kalman Filter (EKF) is implemented in conjunction with a SLAM algorithm. Sensor measurements, together with the position and orientation estimates from the SLAM algorithm, are fused using the EKF.  The Kalman Filter provides an estimation of the vehicle’s complete state. Navigation is accomplished with a custom path planning algorithm which generates flight commands based on the current state estimation. A custom fuzzy controller performs the attitude and position control while maintaining the stability of the quadrotor in hover and translational flight.

Base Station Software

Currently, flights are managed using Base Station software provided by Rotomotion, LLC. However, development is progressing on the SDSM&T custom Base Station software. The software will be capable of managing a multiple vehicle system from one integrated GUI.

Features of the software include:

      -Live video streams

      -Processed video display

      -Sensor data display

      -Multiple artificial horizons display

      -Calibration and tuning capabilities

      -One central map with the capabilities of displaying:

            - Overlaid USGS geo maps

            - Multiple vehicles and status data

            - Flight paths of each vehicle

The map also provides the operator with a user-friendly flight path planning interface. The operator can easily generate stacks of flight commands and monitor the execution of the stacks from within the GUI.

In The News

August 5, 2008 - Team Receives Four Awards at Unmanned Aerial Vehicle Competition

The South Dakota School of Mines and Technology unmanned aerial vehicle (UAV) team received four awards at the International Aerial Robotics Competition held at Fort Benning , Georgia . The team took first place in the 2006 and second in the 2007 competition.

The competition, sponsored by the Association for Unmanned Vehicle Systems International, challenges students to launch an aerial vehicle, navigate a series of global positioning system waypoints and fly three kilometers to a complex of buildings where the vehicle must search the perimeter of each building for a specified symbol. The vehicle then must launch a second vehicle that enters the building, captures video or photos of a specified type of data and transmits that data back to the starting point. The entire operation must be fully automated.

The team received the Best Technical Paper Award, Best T-shirt Design Award and tied with Georgia Tech and Virginia Tech for the Best System Design Award. The team made two fully autonomous flights but did not complete any of the stages. They received more than $8,000 in prize money for their efforts. Chief Engineer, Justin Williamson, thought the competition was a success. �The competition didn't go as we had hoped but it still worked out to where we could demonstrate the capabilities of our system. The team not only made great friends from different schools, but we showed that the South Dakota School of Mines and Technology is a professional competitor in the world of unmanned systems.�

Team member Mark Sauder (industrial engineering 04), and team guest, Reed Christiansen ( Procerus Technologies), received a special award for Sportsmanship for helping the California State University at Northridge (CSUN) team bring their helicopter down from a very unsafe altitude to a lower altitude where their pilot could take over and land it successfully.  The CSUN team was having technical difficulties and Sauder and Christiansen shared their knowledge of controls and understanding of VTOL vehicles to save their helicopter. John Heiberger was also involved in the heroic act but was unrecognized. In announcing the award, the judges stated the award was for actions far beyond the call of duty.

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