EP-4735331-A1 - PAYLOAD CARRYING SYSTEM AND METHOD

EP4735331A1EP 4735331 A1EP4735331 A1EP 4735331A1EP-4735331-A1

Abstract

A payload system for carrying a payload including a platform configured to support the payload, and a payload distribution sensor configured to sense the distribution of the payload on the platform. At least two autonomous aerial vehicles are provided, with coupling arrangements being configured to couple each vehicle to the platform. One or more processing devices configured to determine a payload distribution in accordance with signals from the payload distribution sensor and control operation of the vehicles in accordance with the determined payload distribution to thereby allow the platform and payload to be lifted.

Inventors

Han, Richard Yeh-Whei
KUANTAMA, Endrowednes
Mukhopadhyay, Subhas
James, Alice
SETH, Avishkar

Assignees

Macquarie University

Dates

Publication Date: 20260506
Application Date: 20240627

Claims (1)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1) A payload system for carrying a payload, the system including: a) a platform configured to support the payload; b) a payload distribution sensor configured to sense the distribution of the payload on the platform; c) at least two autonomous aerial vehicles; d) at least two coupling arrangements, each coupling arrangement being configured to couple a respective one of the vehicles to the platform; and, e) one or more processing devices configured to: i) determine a payload distribution in accordance with signals from the payload distribution sensor; and, ii) control operation of the vehicles in accordance with the determined payload distribution to thereby allow the platform and payload to be lifted. 2) The payload system according to claim 1, wherein the coupling arrangements are configured to allow an orientation of each vehicle relative to the platform to be adjusted. 3) The payload system according to claim 2, wherein the orientation includes the pitch, yaw and roll of each vehicle relative to the platform. 4) The payload system according to claim 2 or claim 3, wherein each coupling arrangement includes actuators for controlling an orientation of the respective vehicle relative to the platform and wherein the one or more processing devices are configured to adjust the orientation of each vehicle in accordance with the determined payload distribution. 5) The payload system according to claim 4, wherein each coupling arrangement includes three actuators for controlling a pitch, yaw and roll of the respective vehicle. 6) The payload system according to claim 4 or claim 5, wherein the actuators include rotational servo motors. 7) The payload system according to any one of the claims 1 to 6, wherein each vehicle includes an altitude sensor, and wherein the one or more processing devices are configured to: i) determine vehicle altitudes in accordance with signals from the altitude sensors; and, ii) control operation of the vehicles in accordance with the determined altitudes. 8) The payload system according to claim 7, wherein each altitude sensor includes at least one of: a) a downward facing ranging device; and, b) a downward facing LiDAR. 9) The payload system according to any one of the claims 1 to 8, wherein the payload distribution sensor includes a resistive panel. 10) The payload system according to claim 9, wherein the payload distribution sensor includes orthogonally arranged sensing elements. 11) The payload system according to any one of the claims 1 to 10, wherein each coupling arrangement is magnetically attached to a respective vehicle. 12) The payload system according to any one of the claims 1 to 11, wherein the platform is situated above a centre of lift of each vehicle. 13) The payload system according to any one of the claims 1 to 12, wherein the one or more processing devices are configured to control the vehicles while carrying the load so as to at least one of: a) control an orientation of the platform; b) maintain the platform in a balanced position; c) maintain the platform substantially level while carrying the payload; and, d) maintain forces on the load substantially normal to a plane of the platform. 14) The payload system according to any one of the claims 1 to 13, wherein the one or more processing devices are configured to: a) determine a destination location; and, b) control the vehicles to transport the platform and payload to the destination location. 15) The payload system according to any one of the claims 1 to 14, wherein the one or more processing devices interact with a flight controller of at least one of the vehicles. 16) The payload system according to any one of the claims 1 to 15, wherein the one of the vehicles is a leader vehicle and other ones of the at least two vehicles are follower vehicles. 17) The payload system according to any one of the claims 1 to 16, wherein the system is configured to implement a path planning algorithm to determine a path to the destination. 18) The payload system according to claim 17, wherein the path planning algorithm incorporates asynchronous angle adjustments to resolve the effect of asynchronous angles between the leader and follower vehicles. 19) A method for carrying a payload, the method including: a) providing: i) a platform configured to support the payload; ii) a payload distribution sensor configured to sense the distribution of the payload on the platform; iii) at least two autonomous aerial vehicles; and, iv) at least two coupling arrangements, each coupling arrangement being configured to couple a respective one of the vehicles to the platform; and, b) in one or more processing devices: i) determining a payload distribution in accordance with signals from the payload distribution sensor; and, ii) controlling operation of the vehicles in accordance with the determined payload distribution to thereby allow the platform and payload to be lifted.

Description

PAYLOAD CARRYING SYSTEM AND METHOD Background of the Invention [0001] The present invention relates to a system and method for carrying a load, and in one example, to a system and method for carry a load using multiple unmanned aerial vehicles (UAVs). Description of the Prior Art [0002] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgement or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. [0003] Multirotor UAVs, also referred to as drones, known for their agility and compact size, are increasingly utilized as a prominent platform for air transportation and package delivery. Drones are typically designed for different payload capacities, and the total thrust limitations of individual drones restrict the payload they can lift. Using larger drones to carry high-capacity payloads can be unsafe for people and become too expensive and bulky, thus reducing their stability. [0004] Cooperative aerial manipulation involves multiple drones working together to manipulate objects in the aerial environment, enabling tasks such as object transportation, assembly, and manipulation with enhanced capabilities and coordination. Cooperative UAVs have emerged as a viable solution for handling heavy or oversized payloads that surpass the capabilities of individual robots, as described in Lee, H. and Kim, U. 2021. Estimation and Control of Cooperative Aerial Manipulators for a Payload with an Arbitrary Center-of-Mass. Sensors 2021, Vol.21, Page 6452.21, 19 (Sep.2021), 6452. [0005] Experimental systems for cooperative transport using drones, typically employing two to four drones, have commonly implemented a lift or pull-based method, positioning the drones above or beside the load being transported. These pull-based paradigms all exhibit similar disadvantages, namely, the payload underneath the drones is subject to strong downwash from the drone propellors, typically inducing a pendulum swing that can further disbalance the payload, causing additional strain on the cooperative drones, potentially damaging the payload, and inducing intense vibrations on the drone. At the same time, wind may perturb the balance and introduce load oscillation as well. Additionally, scenarios involving transporting comparatively larger objects might present slipstream issues due to the interference with the propellers’ downwash airflow. [0006] While cooperative, mobile manipulators have been developed to exploit grasping capabilities, their practical implementation is hindered by the complexities associated with multiple aerial robots as discussed for example in Kellermann, R. et al.2020. Drones for parcel and passenger transportation: A literature review. Transportation Research Interdisciplinary Perspectives. 4, (Mar. 2020). Previous approaches have primarily focused on addressing control and coordination challenges by assuming a uniform mass distribution in the payload, simplifying the problem. However, manipulating payloads with non-uniform mass distributions, where the payload's geometry and center of mass differ, introduces significant complexities. [0007] In contrast to the scenario of a single robot, effectively coordinating a team of multiple mobile platforms in sync necessitates additional factors to be considered. These include ensuring synchronized motion among the agents, effectively managing the stresses exerted on the manipulated object, and maintaining the overall stability of the combined system. This is discussed in Bacelar, T. et al.2020. On-board implementation and experimental validation of collaborative transportation of loads with multiple UAVs. Aerospace Science and Technology. 107, (Dec. 2020), 106284 and Mellinger, D. et al. 2011. Design, modeling, estimation and control for aerial grasping and manipulation. (Dec.2011), 2668–2673. [0008] As a result, cooperative manipulation has garnered significant attention in research, primarily focusing on stationary or ground-based mobile manipulators. [0009] In multi-vehicle lift and payload transportation, a sling load configuration offers advantages over a rigidly attached configuration where vehicles are directly connected to the payload. The sling load configuration allows for greater separation between the vehicles and the payload, introducing rotational degrees of freedom that reduce dynamic constraints in the system. However, while using tethers reduces constraints on the vehicles and payload, it introduces multiple vibrational degrees of freedom that can be excited during maneuvers, making control design more complex, especially when the payload's mass, inertia, and aerodynamic properties are uncertain. Additionally, tethers bring the risk of in-flight collisions between vehicles.