Controlling Rotations of an Object

The rotations of blue gun of around two intersecting vertical and horizontal axes are controlled by grounded brown motor and violet linear actuators.
Brown motor makes pink shaft and the gun rotate around vertical axis.
Violet linear actuators make yellow bush of inner circular groove move up down thus control the gun rotation around horizontal axis (via sine mechanism).

Classified list of 2100 videos in channel thang010146 (uploaded till 31 Dec. 2015) including pictures, brief descriptions and YouTube links: