Third Place Winner ($500.00) - Jens Altenburg (Soemmerda, Germany)
Notes from the judges:
- Professionally engineered project. Demonstrates the SX chip well.
- We've seen several autopilots but not one which incorporates so many different concepts.
- This is an appealing and challenging project and Jens made it fly, too.
Downloads for this project:
All files and information © 2005 Jens Altenburg.
Project Description:
Autonomous operating systems, often called robots, fascinate with their behavior. Most of those systems are ground based, that means they have wheel or legs for moving. Robots cannot fly, can’t they? There are some experiments existing like the so called UAV (unmanned air vehicle). Most of them have been developed by universities and sponsored by huge companies. Now, in case of no need of complete autonomous flight an interesting flying vehicle is presented. The combination of a fabulous swept-forward tailless aircraft model and the very fast SX microcontroller made it possible to design a semi autonomous micro air vehicle, called SAM. The special needs of the swept-forward tailless design can be solved by an on board computing system. Semi autonomous means, that a pilot flies the aircraft with a radio, but some functions are supported by electronics. But with all the enthusiasm, the aircraft has to be built as cheap as possible, so that not only rich people can fly, but also students and pupils. The schematics and the basic control software will be published, so everyone has a chance to understand the design and/or improve it.
There are a huge amount of radio controlled aircraft models available. You can buy cheap foam made slow- and fun flyers, or you buy or build expensive semi-scale RC models. If you are a beginner in flying RC models, the lifetime of your model is calculated in minutes. To be a good pilot is a hard job. Now, there is a new material available, the so called EPP. The material looks like normal styro, but is nearly indestructible, really! I got a new developed EPP model, the "Bat" for testing (manufacturer: www.acteurope.de). The model designed by Klaus Westerteicher from ACT-Europe (www.acteurope.de) is a so called swept-forward tailless aircraft (SF). OK, it looks a little bit strange, but it has an wonderful flying behavior.
There is an excellent description about SF aircrafts. We need to know that a well designed aircraft cannot be stalled. Another advantage is the easy to built assembly kit. Only a few components have to be mounted. And last but not least the model is cheap. With such an amount of advantages, there are also some disadvantages. Because the aircraft is controlled by only two ailerons both servo signals have to be mixed. If you are an owner of a computer radio, you program your radio with the mixing parameters. Especially this point looks like a contradiction; cheap model - expensive radio. That's not a good combination for beginners. Another disadvantage is the roll control of the model during approach. Because there are only two ailerons existing, they have to be used as an aileron/elevator combination. During approach (low altitudes) only small swings are allowed.
This system is controlled by an SX based flight control computer (FCC). Let us define some base lines for such an equipment:
- Using of standard 3 channel radio
- Internal mixing capability for two servos
- Third channel controls the engine (PWM signal is generating by the FCC no external motor controller is needed)
- Failsafe function (detecting male function of receiver, noise, over range, etc.)
- Stabilization of the aircraft in roll axis
- Option 1: altitude depending aileron swing
- Option 2: second radio link (ISM-Band) for data transmission, like servo positions, height, temperature, speed, etc. Option 1 and 2 are prepared on the pcb. Because of the limited RAM size of the SX28 (and the limited ROM code size of the CC1B, appx. only 1550 words) both options are not included in the basic software system.
Download the PDF project report (above) for all details of this project.