US 12,673,789 B2 · Autonomous tether management system and method for an unmanned aerial and surface vehicle team

Abstract

The present invention involves systems and methods for tether length management between an unmanned aerial vehicle (UAV), e.g., a drone, and a surface vehicle (SV), dynamically moving ground vehicle or an unmanned SV (USV) base station. The tether length control methodology of the present invention allows for a dynamic moving base station and maintains minimal tether tension, while measuring those dynamic oscillations of the UAV and SV. This novel slack tether tension management ultimately reduces forces and power consumption. A key feature of the present invention is the capability to de-couple the UAV's motion from the base/winch/SV. This enables operation in highly dynamic environments, e.g., maritime, moving ground vehicles, etc.

Claims23

Dependent claims

A method for tether management of an unmanned aerial vehicle (UAV) tethered to a surface vehicle (SV), comprising:

obtaining a radial distance and an altitude difference between the UAV and the SV;
measuring accelerations of the UAV and the SV;
estimating relative position and relative velocity between the UAV and the SV from the radial distance, Δr, the altitude difference, Δz, and the accelerations of the UAV and the SV;
calculating a reference tether length, Lref, from the radial distance and the altitude difference between the UAV and the SV using a 4th-order reference tether length model:
L
ref
=
Δ
⁢
z
⁡
(
f
1
+
f
2
⁢
Δ
⁢
r
Δ
⁢
z
+
f
3
⁢
Δ
⁢
r
2
Δ
⁢
z
2
+
4
3
⁢
Δ
⁢
r
3
Δ
⁢
z
3
+
f
5
⁢
Δ
⁢
r
4
Δ
⁢
z
4
)
.
where f1 through, f5 are empirically derived coefficients;
low-pass filtering the reference tether length using a vertical speed-based gain scheduled coefficient;
measuring actual tether length;
comparing the actual tether length to the low-pass filtered reference tether length;
and
adjusting actual tether length to match the reference tether length.

65 more elements

An autonomous tether management system for maintaining a slack tether between an unmanned aerial vehicle (UAV) and a surface vehicle (SV), comprising:

a SV controller mounted to the SV and including a SV radio configured for bi-directional communication between the SV and the UAV;
a UAV controller including a UAV radio in communication with the SV radio;
a winch in communication with and controlled by the SV controller, the winch configured for adjusting length of the tether;
and
the SV controller further configured for implementing a method for tether management of the UAV tethered to the SV, the method employing a 4th-order reference tether length model
L
ref
=
Δ
⁢
z
⁡
(
f
1
+
f
2
⁢
Δ
⁢
r
Δ
⁢
z
+
f
3
⁢
Δ
⁢
r
2
Δ
⁢
z
2
+
4
3
⁢
Δ
⁢
r
3
Δ
⁢
z
3
+
f
5
⁢
Δ
⁢
r
4
Δ
⁢
z
4
)
where f1 through, f5 are empirically derived coefficients.

60 more elements

Dependencies are inferred from the claim text.

Autonomous tether management system and method for an unmanned aerial and surface vehicle team

Life of this patent

Autonomous tether management system and method for an unmanned aerial and surface vehicle team

Life of this patent

Abstract

Claims23