Dynamic collaboration without communication: Vision-based cable-suspended load transport with two quadrotors

Abstract

Abstract-Transport of objects is a major application in robotics nowadays. While ground robots can carry heavy payloads for long distances, they are limited in rugged terrains. Aerial robots can deliver objects in arbitrary terrains; however they tend to be limited in payload. It has been previously shown that, for heavy payloads, it can be beneficial to carry them using multiple flying robots. In this paper, we propose a novel collaborative transport scheme, in which two quadrotors transport a cable-suspended payload at accelerations that exceed the capabilities of previous collaborative approaches, which make quasi-static assumptions. Furthermore, this is achieved completely without explicit communication between the collaborating robots, making our system robust to communication failures and making consensus on a common reference frame unnecessary. Instead, they only rely on visual and inertial cues obtained from on-board sensors. We implement and validate the proposed method on a real system.

Team NimbRo at MBZIRC 2017: Fast landing on a moving target and treasure hunting with a team of micro aerial vehicles

“…A reference state (including pose, velocity, and angular velocity) is generated which the MAV will try to reach to equilibrate the external influence. Similarly, Gassner, Cieslewski, and Scaramuzza () worked on a leader–follower control to move a bulky object with two MAVs, but the follower used visual perception to track the relative position of the leader and the relative position of a tow that was anchored to the object. Also, in contrast to the previous approach, the anchor point has to be known.…”

Autonomous Cooperative Flight of Rigidly Attached Quadcopters

“…Within the first group, the most common approach is the use of cable-based attachments. This approach allow independent control of the agents, constituting one of the main challenges, the obstacle avoidance between the quadcopters, while ensuring stability of the transported load [23][52] [51]. More interesting for the development of the current thesis are the examples of rigid attachment based collaborative aerial control.…”

Wrench Analysis of Cable-Suspended Parallel Robots Actuated by Quadrotor Unmanned Aerial Vehicles

“…Currently most ACTSs are slung loads from helicopters for the purpose of military or civilian logistics, but the recent increase in the commercialization of unmanned aerial vehicles (UAVs) due to improved onboard sensing and computation, and higher energy density batteries has opened the commercial possibility of using many small UAVs to collaborate towards single tasks [1][2][3]. The use of multiple small UAVs compared to a single larger one is desirable from a safety and redundancy standpoint, as well as allowing for greater reactivity of the system to excitations due to the greater agility of small UAVs [4]. Many types of UAVs exist, however much of the current research including this paper is focused on quadrotors due to their high payload to weight ratio, versatile control, and simple mechanical design [5].…”

“…A subject of great interest currently in the ACTS field is the implementation of decentralized control where the payload is transported by the collective action of multiple quadrotors without explicit communication between each agent. This has been studied for rigid connections [2], and for cable attachments using onboard camera [4] or using either observer or sensor derived tension sensing [13,14] where the stability is shown to relate to the internal forces in the body being transported. In all these works the wrench feasibility and stability of the ACTS is considered, but to the authors' best knowledge there is no systematic quantification of the degree of wrench feasibility nor generic methodology for mapping the extensive wrench set in task space.…”