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 multirotor frame. To overcome the limited payload capabilities in multirotor aerial platforms, the same set of on-board manipulators are used to realize various tasks, primarily the manipulation or grasping of objects of various sizes. Furthermore, they can provide aid in complex navigation tasks by doing physical, contact-based obstacle avoidance and are able to act as adaptive landing gear in uneven terrain. The design requirements and the analysis to realize these tasks is discussed. The proposal is supported with the successful demonstration of these tasks using the aerial multi manipulator system in an outdoor environment. GRAPHICAL ABSTRACT

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.

Owing to Japan’s aging society and labor shortages, the food and agricultural industries are facing a significant demand for robotic food handling technologies. Considering the large variety of food products, available robotic end-effectors are limited. Our primary goal is to maximize the applicability of existing end-effectors and efficiently develop novel ones, and therefore, it is necessary to categorize food products and end-effectors from the viewpoint of robotic handling and establish their relationships through an effective evaluation approach. This study proposes a system for evaluating robotic end-effectors to identify appropriate ones and develop new ones. The evaluation system consists of food categorization based on food properties related to robotic handling, categorization of robotic end-effectors based on their grasping principles, a robotic system with visual recognition based on Robot Operating System 2 (ROS 2) to conduct handling tests, a scoring system for performance evaluation, and a visualization approach for presenting the results and comparisons. Based on food categorization, 14 real food items and their corresponding samples were chosen for handling tests. Seven robotic end-effectors, both commercialized and under development, were selected for evaluation. Using the proposed evaluation system, we quantitatively compared the performance of different end-effectors in handling different food items. We also observed differences in the handling of real food items and samples. The overall performance of an end-effector can be visualized and quantitatively evaluated to demonstrate its versatility in handling various food items.

We herein propose a long-reach aerial manipula-tion to allow the manipulation of objects several meters away from an unmanned aerial vehicle (UAV). The system consists of a multirotor platform with winch mechanism and wire-suspended gripper module equipped with a camera and swing-suppression device. The winch controls the distance of the wire-suspended device from the UAV. To stabilize the device suspended from the UAV by two wires, we developed a swing-suppression device using an IMU and ducted fans. Through experiments, we verified effectiveness of the swing-suppression system; that is, it successfully stabilized the wire-suspended device within a distance of 3.5 m from the UAV. Furthermore, we performed a pick-and-place task using a gripper that was lowered from the UAV by 3 m.

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.

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.