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  • Greg Fletcher March 23, 2013 at 12:39pm

    Robert,

    You are absolutely right. Its just that the only example I have seen were just keeping level. I have been looking at some open code that runs on a 328P and mpu 6050. It could be modified to run a mpu 6000, which I think is I2C and the other is SPI. Then it should run on a Ardu IMU 3. You're also right about the Mount code. Makes for less work on the APM. We just to take the poll/tilt/pan_control_angle and send it thru a spare serial port to the imu 3, at 50 Hz and it would use these as the control setpoints. Outputs using the 3 pwm outputs on the 328p. Some one needs to  write some code for a flash-able esc to control the motors.  With motors now available and the smoother performance over servos, these things will soon be the standard gimbal control method.

  • ionut March 23, 2013 at 12:18pm

    This controller:

    http://flyduino.net/Alex-Mos-Brushless-Gimbal-BLG

  • Rob_Lefebvre March 23, 2013 at 9:43am

    My understanding is that you simply feed these controllers two PWM signals which represent the pitch and roll targets.  (Actually, roll might be fixed as "level" so only requiring a single PWM?)  

    So, I don't know if the APM will play nicely with these currently.  The APM would need to calculate a geometric reference for pitch, and output that, with NO frame stabilization in it.  If the target is 50m away, and the copter is at 50m altitude, the APM would compute a 45° downward pitch, and send that signal to the BLGC.  The BLGC will handle the stabilization from there.  I'm not sure if the APM Mount controller can do that.  But it should be easy to fix, as we're just removing the stabilization portion, not adding anything.

  • Gary McCray March 23, 2013 at 9:06am

    Josh,

    Definitely no bandwidth in APM to run these and also to slow a refresh rate.

    They need a separate controller / motor driver board, but they probably are the way to go.

    At least 3 Companies are gearing up with brushless gimbal motors and although they are technically a stepper motor using an analog microstep, their inter-step behavior tends to be smoother than conventional steppers.

    Real steppers could certainly work as well.

  • Noth666 March 23, 2013 at 7:14am
    The controller with the driver and separate IMU board are about 110r or so, viacopter.eu for example sells them. They are plug and play if the motors are wound the right way, and the IMU is sngle mpu6050 based.
  • Jethro Hazelhurst March 23, 2013 at 7:04am

    I agree! My dream setup: APM3 ( PX4 Hardware, built in brushless gimbal controller), brushless gimbal, hand held ground station with 3D joystick, antennae tracking and fpv head tracking, with an HD video link... oh yes, and a titanium Sponge 3D printed Frame!

  • Rob_Lefebvre March 23, 2013 at 5:37am

    Gary, yes, that video is SHOCKINGLY good.  I'm just absolutely gobsmacked.  We have ARRIVED!  APM is working, and now these gimbals are available at a reasonable cost... I can't wait for this summer!

    Greg, your statements that these can only hold level are no based on fact.  There's no reason why they can't be made to point in any direction. 

  • Jack Crossfire March 23, 2013 at 2:27am

    Judging from

    http://www.rcgroups.com/forums/showthread.php?t=1815204

    they get extremely accurate, fast pointing by PWMing the coils on 3 phase motors & using a very fast IMU on the frame.  You can hear the PWM in the video.  What direct drive motors lacked in torque, they had in speed & precision that servos can't match & that made more stable videos than anything before.

    The technology was apparently pioneered by the DJI Zenmuse, but a guy named Alex Moskalenko in 2012 knew how to lower the cost by rewinding standard RC motors to make them behave like the low cogging stepper motors a camera needs.  It's yet another 1 of those crazy Russian guys, exposed to the right 2 disciplines, applying electromagnetism to solve a photography problem. 

    Runryder posters are still trading servo camera mounts, but they're all going to go brushless in no time.  It's so much more compact than the past gimbals, you'll have the same stability on micro copters that used to take raptor 90's.  It might even bring steadycam stability to phones.  It's basically the 1st device which successfully replaces all the mechanics & tuning in a steadicam with really cheap, actively driven electronics. The days of guys gluing pipes together to stabilize their camcorders are already over.

  • Moderator
    Vladimir "Lazy" Khudyakov March 23, 2013 at 1:00am

    Waiting for electronics...

  • Jethro Hazelhurst March 23, 2013 at 12:31am

    Whoops! Just realized the typo! Sorry!

This reply was deleted.