ActionCam: An Automated Tracking Camera
During a year-long project at the University of Colorado, a team of five other students and I designed and fabricated several iterations of an automated tracking camera using GPS technology. We were the only team in the department that was allowed to work on our own entrepreneurial idea.
Objective
To develop a portable and weatherproof system that smoothly tracks a fast moving object with a camera, while recording professional quality video and photographs.
Final Design
Our final system design consisted of a motorized pan/tilt tripod top, which would autonomously follow a remote module using GPS. The pan/tilt featured two maxxon brushed DC motors with encoders and Allmotion motor controllers. The tracking consisted of two GPS units, one on the tripod and one on the remote module being tracked. System control was accomplished with a LabView program running on a laptop. The LabView program would receive data from both GPS units (one signal through serial and the remote signal through Bluetooth) and determine relative distance and heading between the two units, and then calculate and output control the pan/tilt motors. After discovering the altitude accuracy of GPS was very poor, we added altimeters to the pan/tilt station and remote module in order to determine the altitude difference between the two points.
Pan Tilt Design
- Five components - Machined with CNC
- Efficient, lightweight design
- Center of mass of camera at center of rotation
- Four bearings implemented
- Unviersal tripod/camera 1/4" UNC mount
Software Design
Using GPS made tracking a fast moving object difficult due to a slow position update of only 5 Hz for the module we selected. A large part of of the project was creating an algorithm which would smoothly follow the object being tracked while being able to counteract the inherent delay created by taking discrete measurements at a low frequency. Our final design essentially used low pass filtering to create smooth motion and forward prediction which took advantage of the deterministic time delay associated with the discrete measurements and low pass filtering.
Locational Tracking Design
Our team researched a variety of viable tracking methods, but due to financial constraints and course deadlines, selected GPS as as the most suitable technology due to it's reliability and availability. Our team did extensive testing on several GPS modules in order to determine the most effective solution for our design. Features taken into consideration were position update rate, accuracy and cost. Below is a comparison between a GlobalTop GPS module (mounted on a custom PCB) and a Garmin.
The test show a huge difference in accuracy between the two modules (This test was simply walking the same circle for a long period of time to see how the error drifts). Although the GlobalTop featured a 5Hz update speed and much lower costs, the accuracy of the Garmin was critical to satisfactory tracking
The full details of the project are technical and very gory, but you are welcome to them!
| finalpresentation.pdf |
| finalpresentation.pdf |