Mechanisms for lowering a payload to the ground from a UAV
Embodiments described herein may help to provide medical support via a fleet of unmanned aerial vehicles (UAVs). An illustrative UAV may include a housing, a payload, a line-deployment mechanism coupled to the housing and a line, and a payload-release mechanism that couples the line to the payload, wherein the payload-release mechanism is configured to release the payload from the line. The UAV may further include a control system configured to determine that the UAV is located at or near a delivery location and responsively: operate the line-deployment mechanism according to a variable deployment-rate profile to lower the payload to or near to the ground, determine that the payload is touching or is within a threshold distance from the ground, and responsively operate the payload-release mechanism to release the payload from the line.
1. An unmanned aerial vehicle (UAV) comprising:
a housing;
a payload;
a line-deployment mechanism coupled to the housing and a line, wherein the line-deployment mechanism is controllable to vary a deployment rate of the line;
a payload-release mechanism that couples the line to the payload, wherein the payload-release mechanism is configured to release the payload from the line; and
a control system configured to determine that the UAV is hovering above a delivery location and responsively:
automatically operate the line-deployment mechanism according to a variable deployment-rate profile to lower the payload to or near to the delivery location, wherein the variable deployment-rate profile specifies for the payload to initially descend at a first rate and subsequently, during the descent, to decrease in speed from the first rate;
determine that the payload is touching or is within a threshold distance from the delivery location; and
responsively operate the payload-release mechanism to release the payload from the line.
2. The UAV of claim 1 , wherein the line-deployment mechanism is operable to secure the line during a flight to a delivery location, such that the payload is held at or near the housing during the flight.
3. The UAV of claim 1 , wherein the control system is further configured to determine a variable deployment-rate profile before operating the line-deployment mechanism to lower the payload to the ground.
4. The UAV of claim 1 , wherein, before lowering the payload, the control system is configured to determine the variable deployment-rate profile based on at least one or more of (a) height, (b) wind, (c) environmental factors, and (d) payload characteristics.
5. The UAV of claim 1 , wherein the variable deployment-rate profile specifies a one or more distances and a deployment rate corresponding to each of said one or more distances.
6. The UAV of claim 1 , wherein the UAV further comprises a line-tension sensor, and wherein the control system is configured to:
determine a measure of tension on the line based on data from the line-tension sensor; and
determine that the payload is touching the ground based at least in part on determination that the measure of tension on the line is less than a threshold.
7. The UAV of claim 1 , wherein the payload comprises at least one proximity sensor arranged on the payload so as to provide data that is indicative of a distance between the payload and the ground, and wherein the control system is configured to:
determine that the payload is touching the ground based at least in part on the data provided by the at least one proximity sensor.
8. The UAV of claim 1 , wherein the control system is disposed within the housing.
9. The UAV of claim 1 , wherein the control system is at least partially disposed within the payload.
10. The UAV of claim 1 , wherein the payload includes or takes the form of a medical-support item.
11. The UAV of claim 1 , wherein the line-deployment mechanism comprises a motorized braking system.
12. The UAV of claim 1 , wherein the line-deployment mechanism comprises one or more friction pads.