1,339 research outputs found
Development, analysis and control of a spherical aerial vehicle
With the ability to provide close surveillance in narrow space or urban areas, unmanned aerial vehicles (UAVs) have been of great interest to many scholars and researchers. The spherical aerial vehicle offers substantial design advantages over the conventional small aerial vehicles. As a new kind of small aerial vehicles, spherical aerial vehicle is presented in this paper. Firstly, the unique structure of spherical aerial vehicle is presented in detail. And then the dynamics theory based on this vehicle’s structure is analyzed, and the equations of force and moment acting on the aircraft were deduced. Based on the above, the dynamics model of spherical aerial vehicle is derived and the nonlinear state equation is established. The control system of the spherical aerial vehicle’s flight motion, including the hardware and software parts, is presented concretely. The backstepping control method is used in the state equation to get the stability of the spherical aerial vehicle’s motion. At last, the experimental results and simulation analysis are provided to confirm the feasibility of the spherical aerial vehicle’s flight movement in the air
Design of a Spherical UGV for Space Exploration
The paper presents the design of a spherical UGV (Unmanned Ground Vehicle) for exploration of critical, unknown or extended areas, such as planetary surfaces. Spherical robots are an emerging class of devices whose shape brings many advantages, e.g. omni-directionality, sealed internal environment and protection from overturning. Many dedicated sensors can be safely placed inside the sphere and the robot can roll in any direction without getting stuck in singular configurations. Specifically, the proposed UGV is thought to collect images and environmental data, so required sensors are firstly discussed to evaluate in sequence of the payload in terms of size and energy consumption. The most effective drive mechanism is selected considering several possible concepts and carrying a trade-off process based on the requirements for a space mission. The optimal solution involves the use of a single pendulum: a hanging mass, attached to the central shaft of the sphere, is shifted to produce rolling. The design issues due to the selected mechanism are discussed, showing the effect of design parameters on the expected performance. For instance, the barycenter offset from the center of the sphere plays a crucial role and affects the maximum step or inclines that can be overcomed. Therefore, the pre-design phase is conducted by discussing the functional design of the robot and introducing a differential mechanism for driving and steering. A quasi omni-directionality is achieved and the mechanical components, opportunely designed according to the loads acting on the device, are arranged to match the mission requirements. Moreover, the mechatronic integration is discussed: microcontrollers, drive electronics, sensors and batteries are sized in order to reach 3 hours of continuous operation. The multibody system is finally modelled in Matlab-Simscape to verify the mechanism for the UGV testing in specific cases. Results show that a suitable layout is a 0.5 m diameter spherical UGV with a steel main structure, mounting 2 DC motors that activate a bevel gear by means of pulleys and timing belts. The spherical shell, with the internal mechanism and electronics, has a total mass of 25 kg and from standstill it can climb up to 15 degrees inclines or steps up to 25 mm, as proved by Matlab simulations. Future works will focus on the realization of the physical prototype, as well as navigation and control strategies
BogieCopter: A Multi-Modal Aerial-Ground Vehicle for Long-Endurance Inspection Applications
The use of Micro Aerial Vehicles (MAVs) for inspection and surveillance
missions has proved to be extremely useful, however, their usability is
negatively impacted by the large power requirements and the limited operating
time. This work describes the design and development of a novel hybrid
aerial-ground vehicle, enabling multi-modal mobility and long operating time,
suitable for long-endurance inspection and monitoring applications. The design
consists of a MAV with two tiltable axles and four independent passive wheels,
allowing it to fly, approach, land and move on flat and inclined surfaces,
while using the same set of actuators for all modes of locomotion. In
comparison to existing multi-modal designs with passive wheels, the proposed
design enables a higher ground locomotion efficiency, provides a higher payload
capacity, and presents one of the lowest mass increases due to the ground
actuation mechanism. The vehicle's performance is evaluated through a series of
real experiments, demonstrating its flying, ground locomotion and wall-climbing
capabilities, and the energy consumption for all modes of locomotion is
evaluated.Comment: This paper has been accepted for publication at the IEEE
International Conference on Robotics and Automation (ICRA), London, 202
Autonomous Hybrid Ground/Aerial Mobility in Unknown Environments
Hybrid ground and aerial vehicles can possess distinct advantages over
ground-only or flight-only designs in terms of energy savings and increased
mobility. In this work we outline our unified framework for controls, planning,
and autonomy of hybrid ground/air vehicles. Our contribution is three-fold: 1)
We develop a control scheme for the control of passive two-wheeled hybrid
ground/aerial vehicles. 2) We present a unified planner for both rolling and
flying by leveraging differential flatness mappings. 3) We conduct experiments
leveraging mapping and global planning for hybrid mobility in unknown
environments, showing that hybrid mobility uses up to five times less energy
than flying only
Formation control of a group of micro aerial vehicles (MAVs)
Coordinated motion of Unmanned Aerial Vehicles (UAVs) has been a growing research interest in the last decade. In this paper we propose a coordination model that makes use of virtual springs and dampers to generate reference trajectories for a group of quadrotors. Virtual forces exerted on each vehicle are produced by using projected distances between the quadrotors. Several coordinated task scenarios are presented and the performance of the proposed method is verified by simulations
Virtual Omnidirectional Perception for Downwash Prediction within a Team of Nano Multirotors Flying in Close Proximity
Teams of flying robots can be used for inspection, delivery, and construction
tasks, in which they might be required to fly very close to each other. In such
close-proximity cases, nonlinear aerodynamic effects can cause catastrophic
crashes, necessitating each robots' awareness of the surrounding. Existing
approaches rely on multiple, expensive or heavy perception sensors. Such
perception methods are impractical to use on nano multirotors that are
constrained with respect to weight, computation, and price. Instead, we propose
to use the often ignored yaw degree-of-freedom of multirotors to spin a single,
cheap and lightweight monocular camera at a high angular rate for
omnidirectional awareness of the neighboring robots. We provide a dataset
collected with real-world physical flights as well as with 3D-rendered scenes
and compare two existing learning-based methods in different settings with
respect to success rate, relative position estimation, and downwash prediction
accuracy. We demonstrate that our proposed spinning camera is capable of
predicting the presence of aerodynamic downwash with an score of over 80%
in a challenging swapping task
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