Methods and systems for detecting and resolving failure events when raising and lowering a payload
First Claim
1. A system comprising:
- a tether disposed on a spool, wherein a first end of the tether is non-fixedly wound on the spool;
a payload coupling apparatus structured to mechanically couple a second end of the tether to a payload;
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; and
a control system configured to;
operate the motor to unwind the tether and lower the payload toward the ground;
detect when the payload contacts the ground and responsively initiate a tether over-run process to attempt to release the payload from the payload coupling apparatus, wherein the tether over-run process is repeatable up to a predetermined number of times when the payload does not release from the payload coupling apparatus;
determine that the tether over-run process has been repeated the predetermined number of times without successful release of the payload, and responsively cause the UAV to initiate a flight to a different location, such that the flight of the UAV unwinds the tether and separates the first end of the tether from the spool, thereby releasing the tether from the UAV.
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0 Petitions
Accused Products
Abstract
Described herein are methods and systems for detecting and correcting errors when picking up 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 control the motor to lower the tether and monitor an electric current supplied to the motor to determine whether a payload has detached from the tether. This process of lowering the tether and monitoring the motor current may be repeated up to a predetermined number of times, at which point the control system may operate the motor to detach the tether from the spool, leaving both the tether and the payload behind.
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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, wherein a first end of the tether is non-fixedly wound on the spool; a payload coupling apparatus structured to mechanically couple a second end of the tether to a payload; 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; and a control system configured to; operate the motor to unwind the tether and lower the payload toward the ground; detect when the payload contacts the ground and responsively initiate a tether over-run process to attempt to release the payload from the payload coupling apparatus, wherein the tether over-run process is repeatable up to a predetermined number of times when the payload does not release from the payload coupling apparatus; determine that the tether over-run process has been repeated the predetermined number of times without successful release of the payload, and responsively cause the UAV to initiate a flight to a different location, such that the flight of the UAV unwinds the tether and separates the first end of the tether from the spool, thereby releasing the tether from the UAV. - View Dependent Claims (2, 3, 4, 5)
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6. A system comprising:
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a tether disposed on a spool, wherein a first end of the tether is non-fixedly wound on the spool; a payload coupling apparatus structured to mechanically couple a second end of the tether to a payload; 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; and a control system configured to control the motor to carry out tethered delivery of the payload; wherein the control system is further configured to, during the process of delivering the payload to a target location and while the UAV is in flight, determine that both (a) an unwound length of the tether is greater than a threshold length and (b) a motor current of the motor is greater than a threshold current for at least a predetermined timeout period, and responsively cause the UAV to initiate a flight to a different location, such that the flight of the UAV unwinds the tether and separates the first end of the tether from the spool, thereby releasing the tether from the UAV. - View Dependent Claims (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 control the motor to carry out tethered delivery of the payload; wherein, during a process of picking up the payload to be delivered and while the UAV is over or near to a pickup location, the control system is further configured to; responsive to a determination that the payload coupling apparatus is mechanically coupled to the payload, operate the motor to retract the tether and lift the payload toward the UAV; while retracting the tether with the payload coupled thereto, detect an error condition when both;
(a) the unwound length of tether is greater than a threshold length and (b) a motor current of the motor is greater than a threshold current;make an attempt to correct the error condition by operating the motor to unwind the tether, and then resume retracting the tether; and determine that a predetermined number of attempts to correct the error condition have been made without successfully correcting the error condition, and responsively end the process of picking up the payload and initiate a payload delivery process to return the payload to the ground at or near the pickup location. - View Dependent Claims (12, 13, 14, 15)
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16. 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; and a control system configured to control the motor to carry out tethered delivery of the payload; wherein, during a process of picking up the payload to be delivered, and while the UAV is over or near to a pickup location, the control system is further configured to; operate the motor to unwind the tether and lower the payload coupling apparatus to a payload attachment altitude; after lowering the tether and waiting for a predetermined payload attachment period, perform an attachment verification process that comprises;
(a) operating the motor in the first mode for a predetermined attachment verification period, and (b) determining, based at least in part on a motor current during the predetermined attachment verification period, whether or not the payload coupling apparatus is mechanically coupled to the payload, wherein the control system can lower the payload coupling apparatus and repeat the attachment verification process up to a predetermined number of times when it is determined that the payload coupling apparatus is not mechanically coupled to the payload; anddetermine that the attachment verification process has been repeated the predetermined number of times without successful coupling of the payload coupling apparatus to the payload and responsively initiate a process to cancel pickup of the payload and initiate flight of the UAV to a different location. - View Dependent Claims (17, 18, 19, 20)
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Specification