The 3 DOF of angular acceleration - RC Groups
Thread Tools
This thread is privately moderated by otlski, who may elect to delete unwanted replies.
Feb 01, 2013, 09:49 PM
checkout my Blog
otlski's Avatar

The 3 DOF of angular acceleration

So far out of the 6-DOF, we've discussed the 3-DOF of translational acceleration disturbances. Let's turn for a minute to the 3 -DOF of angular acceleration disturbances. Keep in mind that our gimbal so far has no closed-loop torquer motors to restore position, and let me also say that the example gimbal has frictionless pivot bearings and no cabling between aircraft frame and the outer or inner gimbal axis.

Observe the video here;

Angular Accel Only (0 min 13 sec)

What happens? Under angular acceleration where the center of the acceleration is coincident with the axis pivot, the gimbal axis will remain stationary, fixed staring at its intended target. This is because the frictionless bearings transfer no torque from the moving frame to the camera axis.

T=Ia. Or torque equals inertia times acceleration. Where torque is in Newton meters (N-m), MOI is in Kilogram meters (Kg-m), and angular acceleration is in radians per second per second (rad/sec-sq). Simply rearranging we find that a=T/I. Thus for angular acceleration disturbances as described above, in the presence of any MOI, and the absence of torque transfer; there will be no angular acceleration imparted to the inner camera axis.
Last edited by otlski; Feb 01, 2013 at 10:08 PM.
Sign up now
to remove ads between posts

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion new Pololu IMU 9 DoF Imageer Multirotor Drone Talk 5 Jan 14, 2012 10:35 AM
Sold Natural 6 DOF Head Tracker optical tracking unit for sale Spidious Aircraft - General - Miscellaneous (FS/W) 9 Jan 03, 2012 09:20 PM
Discussion Ardupilot mega + IMU razor 6 DOF for tricopter Iboxx83 Multirotor Drone Talk 3 May 24, 2011 04:51 PM
Discussion 6-DOF Tracker possibility?? fireslayer26 Multirotor Drone Talk 2 Jul 12, 2010 07:45 PM
Discussion New 6-DOF IMU voiceafx UAV - Unmanned Aerial Vehicles 45 Jun 28, 2010 02:48 PM