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Pan Tilt Movement
  • Hello

    Assuming the motors are strong enough, what is the maximal speed for (pan,tilt,roll) camera movements? In the android app the fastest speed is 500 which is not so fast. Is this the limit of the serial protocol, or just for this app? What if the position input comes over RC?
  • Stabilisation and camera movements are two different things. the speed is for camera movement and 500 degrees in second is very fast for any video purpose.
  • I know that. 500 is just the value which is shown in the app, its much slower than 500 deg/s. The question is if the limitation comes from the app, the serial api protocol or the controller?
  • I have not tested, but think the max speed on computer GUI is 256 coming from 8 bit integer used for that value, just guessing, but you could check from serial API definition if it uses 8 bit.
  • In the serial doc it says "2s" which I assume is -32768 to 32767. Units is 0.1220740379 degree/sec. So max speed should be 4000 deg/s. When i measure the max speed which I can apply with the android app it is about 40 deg/s. Is it possible to control the gimbal with the computer GUI?
  • Not control but tune. On GUI the max value for Max speed is 255. This sets the range for RC control.

    I do not know the app you are talking about or what it does, but maybe its max speed is limited by the max speed set on the controller via the GUI, maybe you can tune the max speed with the app?

    I have never needed more than 100 deg/s max speed.
  • i'm talking about this app: http://www.basecamelectronics.com/downloads/android/

    I want to test some tracking algorithms, so I'm thinking most of the time the tracking speed would be slow but it would good to know that there is no limitiation on the control side. I think 200-300 deg/s would be fine, but 40 deg/s is definitely to slow
  • From the Serial API:
    ANGLE_ROLL, ANGLE_PITCH, ANGLE_YAW
    2s -32768 32767 Target angle. Ignored in the MODE_SPEED mode.
    If mode=MODE_RC, it specifies RC data in range -500..500
    Units: 0,02197265625 degree.

    Haven't tested, but to me this is referring to the RC signal, not the speed, which is always in the range of 1000 - 2000. In theory, you could greatly increase the gimbal's angular speed by increasing the speed parameter on the RC tab of the SimpleBGC GUI (or presumably in the Android app as well).
  • Ok i managed to write a c++ program which can send angle and speed commands to the gimbal, but it doesn't work for the combined speed-angle-mode. How do the inputs need to look like? Lets say I'm want to go from 0deg to 10deg in 1 second, do I just send angle=10 and speed=10 or do I have to send a ramp on the angle?
  • You have ramp both speed and angle. Take care of smooth acceleration and stoping.
  • What happens if the values do not match?
  • Sudden moves, unexpected moves. They do not have to mach exactly, but the closer, the the smoother it will move and it can move very smooth.
  • So whats the best way to do it? I have a trajectory which I want to follow, so I calculate the corresponding velocity, sample at 50 Hz and send the commands?
  • You need to calculate both velocity and angle. You can use limit acceleration to smooth it and outer P (GUI advanced)