Unmanned aerial vehicle and payload delivery system

1. A method performed by a processing system, the method comprising:

causing an unmanned aerial vehicle (UAV) to pick up and secure a payload at a first physical location using a retractable delivery mechanism attached to a main body of the UAV, wherein the retractable delivery mechanism includes a payload holder;

generating control commands configured to cause the UAV to fly from the first location to a designated second physical location;

obtaining first sensor data at the designated second physical location using one or more sensors on the main body of the UAV;

based on the first sensor data, obtaining one or more characteristics of an area including a plurality of candidate delivery surfaces at the second physical location;

obtaining rule data indicative of one or more criteria associated with an appropriate delivery surface;

based on the obtained one or more characteristics and the obtained rule data, selecting, from the plurality of candidate delivery surfaces, a first delivery surface in the area; and

causing the retractable delivery mechanism to lower the payload holder towards the selected first delivery surface;

after the payload holder has been at least partly lowered by the retractable delivery mechanism:

obtaining second sensor data using one or more sensors on the payload holder;

based on the second sensor data, obtaining one or more other characteristics of a plurality of other candidate delivery surfaces; and

automatically selecting, from the plurality of other candidate delivery surfaces, a second delivery surface, different from the first delivery surface, based on a comparison between the one or more other characteristics and the obtained rule data; and

causing the retractable delivery mechanism to lower the payload onto the second delivery surface.

2. The method of claim 1 , wherein the obtained one or more characteristics include one or more of:

a type of material on at least part of the area;

a size of at least part of the area;

a slope of at least part of the area;

a distance between at least part of the area and a selected delivery location; and

a proximity from at least part of the area to one or more other detected objects.

3. The method of claim 1 , comprising obtaining data indicative of one or more current environmental conditions and selecting the first delivery surface at least in part on the current environmental condition data.

4. The method of claim 1 , wherein the rule data include one or more temporal criteria, and the method comprises selecting the first delivery surface at least in part on a current time.

5. The method of claim 1 , comprising:

obtaining at least one of:

(i) data indicative of a prior history of successful or unsuccessful delivery to the are; or

(ii) data indicative of a prior history of successful or unsuccessful delivery to other areas with one or more characteristics corresponding to the one or more characteristics of the area; and

selecting the first delivery surface based at least in part on the prior history data.

6. The method of claim 1 , comprising:

selecting the first delivery surface from the plurality of candidate surfaces based on a comparison between the obtained one or more characteristics and the rule data.

7. The method of claim 1 , comprising:

obtaining a specification of a delivery area at the designated second physical location;

using the first sensor data, identifying the area based on the delivery area specification.

8. The method of claim 7 , wherein the area is identified using an object model, the area being identified using object recognition based on the object model.

9. The method of claim 7 , wherein the specification includes a target image pattern, and wherein the area is identified using image pattern recognition based on the target image pattern.

10. The method of claim 7 , wherein the specification includes a target signal pattern, and wherein the area is identified based on recognition of the target signal pattern.

11. The method of claim 1 , wherein the second sensor data comprises a signal identified using at least one of Wi-Fi, Bluetooth and Infrared short range radio signals.

12. The method of claim 1 , comprising:

obtaining data defining a descent cone defining an allowable range of three-dimensional positionings of the payload holder with respect to a position above the selected first or second delivery surface;

operating the retractable delivery mechanism to lower the payload holder from the main body towards the selected first or second delivery surface;

monitoring a current position of the payload holder with respect to the three-dimensional positionings defining the descent cone; and

operating a propulsion system of the UAV to control a position of the payload holder with respect to the three-dimensional positionings defining the descent cone.

13. The method of claim 12 , wherein the propulsion system comprises a propulsion sub-system attached to the payload holder, and the method comprises causing the propulsion sub-system to apply a thrust force to the payload holder to adjust the position of the payload holder with respect to the descent cone.

14. The method of claim 12 , in which the three dimensional positionings of the descent cone are determined on the basis of one or more obstacles in the vicinity of the selected delivery surface.

15. The method of claim 12 , in which the three dimensional positionings of the descent cone are determined on the basis of atmospheric conditions at the selected delivery location.

16. The method of claim 12 , comprising:

obtaining data defining an allowable range of three-dimensional positionings of the main body while the retractable delivery mechanism is lowering the payload holder from the main body towards the selected first or second delivery surface; and

operating the propulsion system to control a position of the main body with respect to the allowable range of three-dimensional positionings.