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In this work, a new method for aerial robot remote sensing using stereo vision is proposed. A variable baseline and flexible configuration stereo setup is achieved by separating the left camera and right camera on two separate quadrotor aerial robots. Monocular cameras, one on each aerial robot, are used as a stereo pair, allowing independent adjustment of the pose of the stereo pair. In contrast to conventional stereo vision where two cameras are fixed, having a flexible configuration system allows a large degree of independence in changing the configuration in accordance with various kinds of applications. Larger baselines can be used for stereo vision of farther away targets while using a vertical stereo configuration in tasks where there would be a loss of horizontal overlap caused by a lack of suitable horizontal configuration. Additionally, a method for the practical use of variable baseline stereo vision is introduced, combining multiple point clouds from multiple stereo baselines. Issues from using an inappropriate baseline, such as estimation error induced by insufficient baseline, and occlusions from using too large a baseline can be avoided with this solution.

In aerial manipulation, the position and size of a manipulator attached to an aerial robot defines its workspace relative to the robot. However, the working region of a multipurpose robot is determined by its task and is not always predictable prior to deployment. In this paper, the development of a multipurpose manipulator design for a three-armed UAV with a large workspace around its airframe is proposed. The manipulator is designed to be lightweight and slim in order to not disrupt the UAV during in-flight manipulator movements. In the experiments, we demonstrate various advanced and critical tasks required of an aerial robot when deployed in a remote environment, focusing on the landing and docking tasks, which is accomplished using a single manipulator system.

Aerial manipulation: physical interaction with the environment by using a robotic manipulator attached to the airframe of an aerial robot. In the future one can expect that aerial manipulation will greatly extend the range of possible applications for mobile robotics, especially multirotor UAVs. This can range from inspection and maintenance of previously hard to reach pieces of infrastructure, to search and rescue applications. What kind of manipulator is attached to what position of the airframe is a key point in accomplishing the aerial robot’s function and in the past, various aerial manipulation solutions have been proposed. This review paper gives an overview of the literature on aerial manipulation that have been proposed so far and classifies them by configuration of the workspace and function.

This paper describes the concept, design and realization of a novel manipulator system for a multirotor aerial robot. The proposed manipulator system consists of three robotic arms attached to a mu...

We propose a multirotor aerial robot for high-pressure washing task. The robot consists of a multi rotor platform, an add-on planar translational driving system(ATD) and a high-pressure washing system. The ATD is equipped on the multirotor and consists of three ducted fans that can generate the force on horizontal plane. The ATD also allows multirotor to suppress the reaction force generated by nozzle of high-pressure washing system and spray water accurately. In this study, we focus on the development of the proposed aerial robot system. Through experiment, we show the successful water spraying by suppressing the reaction force while flying.

Robot interaction with the environment is preferable to help and respond quickly during disasters. Unmanned aerial vehicles (UAV s) are among the quickest robotic platforms that can be deployed on the field. However, if a UAV lands on an unknown site, it will be unable to take-off if the UAV frame is not level, which might be due to shifting of the ground or unstable platforms. We examine the challenge of UAV takeoff from a sloped platform in this work, and we suggest the design and use of a three-arm aerial manipulator system to autonomously keep the UAV frame leveled at all times for safe take-off.

UAVs are one of the fastest types of robots that can be deployed in a remote environment. Unfortunately, they have a limited flight time and therefore may need to stop occasionally in an unknown, uncontrolled area. However, conventional UAVs require flat and stationary surfaces for a safe landing and take-off. Some studies on adaptive landing approach for UAVs can be found in the past, but adaptive take-off from non-flat surfaces has not been discussed for the most part, yet. In this work, we discuss the problems associated with a conventional UAV take-off from non-flat surfaces and provide a novel approach for UAV take-off from a sloped or rocking surface. We also discuss the design of a novel multitasking three-arm aerial manipulator system with parallel link mechanism and achieve the above-mentioned task. With experiments, we show that the system can provide stability for a UAV landing on a rocking surface that allows for a safe take-off.

In this study, we propose a multirotor aerial robot for high-pressure washing tasks at high altitudes. The aerial robot consists of a multirotor platform, an add-on planar translational driving system (ATD), a visual sensing system, and a high-pressure washing system. The ATD consists of three ducted fans, which can generate force in all directions on the horizontal plane. The ATD also allows the multirotor to suppress the reaction force generated by the nozzle of a high-pressure washing system and inject water accurately. In this study, we propose a method to precisely inject water by installing an ATD in the multirotor and using its driving force to suppress the reaction force and move the multirotor while keeping its posture horizontal. The semi-autonomous system was designed to allow the operator to maneuver the multirotor while maintaining a constant distance from the wall by the sensor feedback with onboard LiDAR or stereo camera. In the experiment, we succeeded in performing the high-pressure washing task in a real environment and verified that the reaction force generated from the nozzle was actually suppressed during the task.

In this paper, multiple micro UAVs (Unmanned Aerial Vehicles) are used to carry small hooks tethered to a heavy load, providing movement of the load within a three-dimensional workspace. We propose an active tethered hook. By moving and attaching the hook to an elevated location and winding the wire with a winch mechanism attached to a load holder, a heavy object can be moved that far exceeds the payload capability of a micro UAV. An RGB-D camera is mounted on the load holder to detect a suitable position to hook at the elevated position, measure the relative position between the micro UAV and the target and perform position control based on the feedback. We verified the hook attachment using this method and examined the hook selection method according to the conditions. Through experiments, it is confirmed that the detection of a rod-shaped object using the point cloud and the position measurement of the micro UAV using a marker were executed accurately. We also confirmed and demonstrated that it is possible to attach the hook to a target in autonomous flight.

This paper proposes a mechanism for a multirotor unmanned aerial vehicle to perch at the tip of a cylindrical object. The proposed mechanism does not require an additional actuator such as a motor by converting its own weight into a gripping force at the time of perching. It also shows that a gripping force larger than its own weight can be generated based on a boost mechanism by appropriately selecting the design parameters. In addition, the proposed mechanism has a structure that can be not only used for perching at the tip of a cylindrical object, but also as a landing gear when landing on flat ground. Furthermore, we attached a depth camera to the proposed mechanism and obtain color and depth images of the target object to be grasped while flying so that automatic positioning can be executed based on the acquired images. Through indoor and outdoor experiments, it was confirmed that the expected perching and landing could be performed.

We propose an add-on planar translational driving system (ATD) which can be equipped on a multirotor platform for aerial manipulation. The device is lightweight and consists of three ducted fans controlled via an on-board CPU. It uses a simple control method and enables a multirotor to perform positioning and generate force in two dimensions while keeping the airframe horizontal. By translating the multirotor without changing attitude, it can more smoothly and easily perform many types of aerial manipulation tasks with higher positioning accuracy. In this paper, we mainly show the design, modeling, and control of the ATD. Several preliminary experiments were performed to verify the positioning accuracy and effectiveness of the system. In addition, we successfully performed the push and pull task using a rigid arm.

We describe the concept, design and implementation of a unique manipulator system for a multirotor aerial vehicle. The proposed manipulator system consists of three robotic arms attached to a multirotor airframe with the objective to provide the ability to manipulate single or multiple objects as well as aid in complex navigation tasks by doing contact based obstacle avoidance and acting as adaptive landing gear in uneven terrain. In this paper we primarily focus on the description and experimentation of one of the tasks achievable by the proposed aerial multi-manipulator system: landing a multirotor aerial vehicle on an uneven surface. Deploying the on-board manipulator as landing gears reduces the hardware carried by the vehicle while additionally providing the ability to land in unstructured and commonly difficult to land terrain.

We have proposed airborne docking using two multi-rotor aerial robots. This paper presents a transport multi-rotor UAV with winch mechanism and a small multi-rotor with onboard locolization and mobile manipulation system. The winch mechanism enables the UAV to lower and raise a bar to transport another UAV attached to it. The airborne docking method used in our work is chosen in order to avoid the effect of downwash generated by the multi-rotors. With experiments we have verified the possibility of airborne docking, and evaluated how it influences the transport multi-rotor UAV as the load is changed, using the IMU data of UAV.

We describe the concept, design and implementation of an aerial robot that is able to achieve precise and complex manipulation tasks at elevated altitudes. The aerial robot in this study consists of a hexarotor platform, a top-mounted gripper module and a robotic manipulator mounted at the bottom of the air-frame. The top-mounted gripper is used to grasp a bar-like object located above the air-frame with the intention to bring the system to a stable resting position at high altitudes. During the process of grasping, the translational and rotational movements of the gripper module is autonomously controlled based on visual feedback obtained from the on-board camera. This, in combination with the manual control of the air-frame, helps the operator to easily achieve grasping a targeted object. After fixing the robot-frame to a suitable target, the bottom-mounted manipulator is used to perform diverse manipulation task. The end-effector of the bottom-mounted manipulator is also able to manipulate the work area above the air-frame by reaching through the space of the arms of the multirotor frame. The combination of a bottom-mounted 2 DOF manipulator and a 1 DOF rotation mechanism of the top mounted gripper results in a three-axis vertical articulated manipulator system able to operate at elevated altitudes.