Methods and systems for raising and lowering a payload
First Claim
1. A system comprising:
- a tether disposed on a spool;
a motor arranged in an unmanned aerial vehicle (UAV), wherein operating the motor in a first mode and a second mode respectively counters and assists unwinding of the tether due to gravity;
a payload coupling apparatus structured to mechanically couple the tether to a payload;
a payload latch switchable between a closed position that prevents the payload from being lowered from the UAV and an open position that allows the payload to be lowered from the UAV; and
a control system configured to determine that the UAV is located at a pickup location and responsively operate in a payload pickup mode, wherein during operation in the payload pickup mode the control system is configured to;
open the payload latch;
operate the motor to unwind a predetermined length of the tether corresponding to an expected payload attachment altitude for the payload coupling apparatus;
after unwinding the predetermined length of the tether and waiting for a predetermined payload attachment period, operate the motor in the first mode for a predetermined attachment verification period;
determine, based at least in part on motor current during the predetermined attachment verification period, that the payload coupling apparatus is mechanically coupled to the payload;
responsive to the determination that the payload coupling apparatus is mechanically coupled to the payload, operate the motor to retract the tether;
while retracting the tether, determine that both;
(a) an unwound length of the tether is less than a threshold length and (b) motor current during the retraction of the tether is greater than a threshold current, and responsively operate the motor to pull the payload into a receptacle on a lower surface of the UAV; and
after operation of the motor to pull the payload into the receptacle, close the payload latch to secure the payload in the receptacle.
2 Assignments
0 Petitions
Accused Products
Abstract
Described herein are methods and systems for picking up, transporting, and lowering a payload coupled to a tether of a winch system arranged on an unmanned aerial vehicle (UAV). For example, the winch system may include a motor for winding and unwinding the tether from a spool, and the UAV'"'"'s control system may operate the motor to lower the tether toward the ground so a payload may be attached to the tether. The control system may monitor an electric current supplied to the motor to determine whether the payload has been attached to the tether. In another example, when lowering a payload, the control system may monitor the motor current to determine that the payload has reached the ground and responsively operate the motor to detach the payload from the tether. The control system may then monitor the motor current to determine whether the payload has detached from the tether.
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Citations
20 Claims
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1. A system comprising:
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a tether disposed on a spool; a motor arranged in an unmanned aerial vehicle (UAV), wherein operating the motor in a first mode and a second mode respectively counters and assists unwinding of the tether due to gravity; a payload coupling apparatus structured to mechanically couple the tether to a payload; a payload latch switchable between a closed position that prevents the payload from being lowered from the UAV and an open position that allows the payload to be lowered from the UAV; and a control system configured to determine that the UAV is located at a pickup location and responsively operate in a payload pickup mode, wherein during operation in the payload pickup mode the control system is configured to; open the payload latch; operate the motor to unwind a predetermined length of the tether corresponding to an expected payload attachment altitude for the payload coupling apparatus; after unwinding the predetermined length of the tether and waiting for a predetermined payload attachment period, operate the motor in the first mode for a predetermined attachment verification period; determine, based at least in part on motor current during the predetermined attachment verification period, that the payload coupling apparatus is mechanically coupled to the payload; responsive to the determination that the payload coupling apparatus is mechanically coupled to the payload, operate the motor to retract the tether; while retracting the tether, determine that both;
(a) an unwound length of the tether is less than a threshold length and (b) motor current during the retraction of the tether is greater than a threshold current, and responsively operate the motor to pull the payload into a receptacle on a lower surface of the UAV; andafter operation of the motor to pull the payload into the receptacle, close the payload latch to secure the payload in the receptacle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system comprising:
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a tether disposed on a spool; a motor arranged in an unmanned aerial vehicle (UAV), wherein operating the motor in a first mode and a second mode respectively counters and assists unwinding of the tether due to gravity; a payload coupling apparatus structured to mechanically couple the tether to a payload; a control system configured to determine that the UAV is located at a target location and responsively operate in a delivery mode, wherein during operation in the delivery mode the control system is configured to; operate the motor to unwind the tether according to a predetermined descent profile; determine that an unwound length of the tether is greater than a threshold length and responsively operate in a pre-touchdown mode, wherein the threshold length corresponds to a predetermined near-ground altitude of the payload; wherein operating in the pre-touchdown mode comprises; (a) operating the motor such that the tether continues to unwind according to the predetermined descent profile, (b) monitoring both motor current and motor speed, and (c) determining that (i) the motor current is less than a predetermined payload-uncoupling current and (ii) the motor speed is less than a predetermined payload-uncoupling speed, and responsively switch to operation in a possible-touchdown mode; during operation in the possible-touchdown mode, analyze the motor current to verify touchdown of the payload; and upon verifying touchdown of the payload, operate the motor in the second mode such that over-run of the tether and payload coupling apparatus occurs. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification