15.4 : Absolute Motion Analysis- General Plane Motion

Visualize a drone, with its propellers spinning rapidly, hovering mid-air. The fascinating movements and operations of this drone can be comprehended by applying the principle of general plane motion.

As the drone's propellers rotate, an upward force is generated that counteracts the force of gravity, enabling the drone to lift off from the ground. This initial movement of the drone is along a straight path, representing a form of translational motion. In this phase, every point on the drone moves the same distance in the same direction.

Once the drone is airborne, its motion becomes more complex. Consider any specific point on the drone, say point P. This point P is in constant motion while the drone is in flight. The journey of point P is not a straight line but rather a curved trajectory. This curved path results from two combined motions - curvilinear translational motion and rotational motion, contributing to general plane motion. The flight of a drone involves intricate maneuvers. Its translational motion comprises forward or backward shifts and ascents or descents, depending upon the controller's inputs. Simultaneously, its rotational motion includes pitch (tilting up or down), yaw (turning left or right), and roll (rotation around its central axis) around the three axes of rotation. This multifaceted motion of the drone arises from the combination of rotational motion around its center of gravity and the translational motion propelled by its rotors.

Eventually, when the drone lands, the rotational and translational motions cease, marking the end of the general plane motion. As a result, the earlier mentioned point P also comes to rest, signifying the termination of the drone's flight.