I am looking to make an electronic steering system for my magnet steered free flight model aircraft. GPS is not allowed by the rules. A gyro compass seems to be the answer, but I have not found any at a reasonable price. A gyro updated by an electronic compass to correct drift would also work I think. The aircraft dynamics are too much for a tilt compensated magnetometer.
Use a heading hold gyro for R/C heli.. Input to gyro and servo is an inexpensive servo tester from Hobby King or Servo City which would give you an adjustable pulse "tweek" for current condtions... if I remember right, 150/msec pulse is "centered servo". PWM drift might be a problem from the servo tester but I don't know how accurate they are over time.. use an o-scope for testing.
pm if you wish..
Al
Hi Thomas, I am an F1E competitor from Hungary.
I make F1E gliders since 1996, but I only saw the Italians (Maurizio Tomazzoni) and the Swiss (Andreas Tschanz) using electronic compasses. It may be because the construction of a mechanical compass does not need electrical engineering skills. However I also want to change to electronic, I think it has future in F1E. Developing more in the mechanical ones is impossible.
The idea of F1E is to slope soar by flying down a slope into the wind. The objective is time in the air up to a maximum of from 3 to 7 minutes depending on the slope length and the wind velocity. Five flights are followed by a fliy off if needed for those with five maxes. This is free flight so the steering to maintain heading into the wind must be autonomous. No radio control and no GPS. Current practice is to use a forward steering rudder operated by a powerful and heavy magnet acting as a compass. The magnet and the rudder fixed to it remain aligned with the magnetic field of the Earth as long as wings are level. When the aircraft yaws, the rudder is automatically deflected and steers the aircraft back to the desired heading. Unfortunatly, when the aircraft pitches or rolls the magnet is no longer aligned with the Earth's magnettic field and has no power to correct heading until the aircraft returns to wings level. free flight models have automatic stability but they respond to gusts by rolling and yawing before returning to wings level on another heading. This can drive the model back into the slope or send it sideways to a less desirable area like trees .
What I would like to do is develop an electronic steering system that is autonomous and not GPS aided and that will resist the gust response of the aircraft and steer it back to the desired heading immediatly. I had thought of steering by wing spoilers controlled by a gyro compass. My friends in F1E have tried gyro only controlled rudders and found that they drift unaccepably. They have also tried compass controlled rudders and found that they cannot handel the pitch and roll of the models and lead to a spiral dive. One friend in Italy has a three axis magnetometer controlled rudder that works in very light winds in southern locations where the magnetic field is flatter to the Earth. In Germany at the World Champs his system could not handle medium winds and the more northern location and went into a spiral dive.
A possible solution is a gyro that is drift corrected to magnetic north perodically by a magnetometer when wings are level. Basucally a two piece simple gyro compass.
Has anyone tried any steering systems like these or is there a better idea out there ?
Is the idea of the F1E comp to fly a straight line? I've done work in this area and seen some of the F1E stuff online. The dynamics would probably be fine for a normal tilt compensated magnetometer. However adding a gyro and washing out the accelerometers when in turns would have to be done. But because these things are free flight anyway their dynamics are relatively low in comparison to full up autopilot IMU's. You may estimate your magnetic heading wrong here or there but becuase the dynamics are so low I would put a lot of money on it still keeping the aircraft headed down the slope for sure
3 axis magnetometer or 3 magnetometers fixed 90 degrees to one another should it and with a reasonable price. Although this would not take into acount for roll of the airplane, so maybe a accelerometer would be need. That will work as long as what ever the aircraft is doing isn't to extream. Then a gyro or 3 would be needed also. What is this for?
Comments
pm if you wish..
Al
I make F1E gliders since 1996, but I only saw the Italians (Maurizio Tomazzoni) and the Swiss (Andreas Tschanz) using electronic compasses. It may be because the construction of a mechanical compass does not need electrical engineering skills. However I also want to change to electronic, I think it has future in F1E. Developing more in the mechanical ones is impossible.
What I would like to do is develop an electronic steering system that is autonomous and not GPS aided and that will resist the gust response of the aircraft and steer it back to the desired heading immediatly. I had thought of steering by wing spoilers controlled by a gyro compass. My friends in F1E have tried gyro only controlled rudders and found that they drift unaccepably. They have also tried compass controlled rudders and found that they cannot handel the pitch and roll of the models and lead to a spiral dive. One friend in Italy has a three axis magnetometer controlled rudder that works in very light winds in southern locations where the magnetic field is flatter to the Earth. In Germany at the World Champs his system could not handle medium winds and the more northern location and went into a spiral dive.
A possible solution is a gyro that is drift corrected to magnetic north perodically by a magnetometer when wings are level. Basucally a two piece simple gyro compass.
Has anyone tried any steering systems like these or is there a better idea out there ?