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 Drones


Learning Hybrid Policies for MPC with Application to Drone Flight in Unknown Dynamic Environments

arXiv.org Artificial Intelligence

In recent years, drones have found increased applications in a wide array of real-world tasks. Model predictive control (MPC) has emerged as a practical method for drone flight control, owing to its robustness against modeling errors/uncertainties and external disturbances. However, MPC's sensitivity to manually tuned parameters can lead to rapid performance degradation when faced with unknown environmental dynamics. This paper addresses the challenge of controlling a drone as it traverses a swinging gate characterized by unknown dynamics. This paper introduces a parameterized MPC approach named hyMPC that leverages high-level decision variables to adapt to uncertain environmental conditions. To derive these decision variables, a novel policy search framework aimed at training a high-level Gaussian policy is presented. Subsequently, we harness the power of neural network policies, trained on data gathered through the repeated execution of the Gaussian policy, to provide real-time decision variables. The effectiveness of hyMPC is validated through numerical simulations, achieving a 100\% success rate in 20 drone flight tests traversing a swinging gate, demonstrating its capability to achieve safe and precise flight with limited prior knowledge of environmental dynamics.


GCBF+: A Neural Graph Control Barrier Function Framework for Distributed Safe Multi-Agent Control

arXiv.org Artificial Intelligence

Distributed, scalable, and safe control of large-scale multi-agent systems (MAS) is a challenging problem. In this paper, we design a distributed framework for safe multi-agent control in large-scale environments with obstacles, where a large number of agents are required to maintain safety using only local information and reach their goal locations. We introduce a new class of certificates, termed graph control barrier function (GCBF), which are based on the well-established control barrier function (CBF) theory for safety guarantees and utilize a graph structure for scalable and generalizable distributed control of MAS. We develop a novel theoretical framework to prove the safety of an arbitrary-sized MAS with a single GCBF. We propose a new training framework GCBF+ that uses graph neural networks (GNNs) to parameterize a candidate GCBF and a distributed control policy. The proposed framework is distributed and is capable of directly taking point clouds from LiDAR, instead of actual state information, for real-world robotic applications. We illustrate the efficacy of the proposed method through various hardware experiments on a swarm of drones with objectives ranging from exchanging positions to docking on a moving target without collision. Additionally, we perform extensive numerical experiments, where the number and density of agents, as well as the number of obstacles, increase. Empirical results show that in complex environments with nonlinear agents (e.g., Crazyflie drones) GCBF+ outperforms the handcrafted CBF-based method with the best performance by up to 20% for relatively small-scale MAS for up to 256 agents, and leading reinforcement learning (RL) methods by up to 40% for MAS with 1024 agents. Furthermore, the proposed method does not compromise on the performance, in terms of goal reaching, for achieving high safety rates, which is a common trade-off in RL-based methods.


Short vs. Long-term Coordination of Drones: When Distributed Optimization Meets Deep Reinforcement Learning

arXiv.org Artificial Intelligence

Swarms of autonomous interactive drones, with the support of recharging technology, can provide compelling sensing capabilities in Smart Cities, such as traffic monitoring and disaster response. Existing approaches, including distributed optimization and deep reinforcement learning (DRL), aim to coordinate drones to achieve cost-effective, high-quality navigation, sensing, and charging. However, they face grand challenges: short-term optimization is not effective in dynamic environments with unanticipated changes, while long-term learning lacks scalability, resilience, and flexibility. To bridge this gap, this paper introduces a new progressive approach that combines short-term plan generation and selection based on distributed optimization with a DRL-based long-term strategic scheduling of flying direction. Extensive experimentation with datasets generated from realistic urban mobility underscores an outstanding performance of the proposed solution compared to state-of-the-art. We also provide compelling new insights about the role of drones density in different sensing missions, the energy safety of drone operations and how to prioritize investments for key locations of charging infrastructure.


Security Considerations in AI-Robotics: A Survey of Current Methods, Challenges, and Opportunities

arXiv.org Artificial Intelligence

Robotics and Artificial Intelligence (AI) have been inextricably intertwined since their inception. Today, AI-Robotics systems have become an integral part of our daily lives, from robotic vacuum cleaners to semi-autonomous cars. These systems are built upon three fundamental architectural elements: perception, navigation and planning, and control. However, while the integration of AI-Robotics systems has enhanced the quality our lives, it has also presented a serious problem - these systems are vulnerable to security attacks. The physical components, algorithms, and data that make up AI-Robotics systems can be exploited by malicious actors, potentially leading to dire consequences. Motivated by the need to address the security concerns in AI-Robotics systems, this paper presents a comprehensive survey and taxonomy across three dimensions: attack surfaces, ethical and legal concerns, and Human-Robot Interaction (HRI) security. Our goal is to provide users, developers and other stakeholders with a holistic understanding of these areas to enhance the overall AI-Robotics system security. We begin by surveying potential attack surfaces and provide mitigating defensive strategies. We then delve into ethical issues, such as dependency and psychological impact, as well as the legal concerns regarding accountability for these systems. Besides, emerging trends such as HRI are discussed, considering privacy, integrity, safety, trustworthiness, and explainability concerns. Finally, we present our vision for future research directions in this dynamic and promising field.


Drones attack deep in Russia as Medvedev threatens Ukraine's 'existence'

Al Jazeera

Russia and Ukraine traded deadly aerial attacks on civilian centres in the past week of the war, but Ukraine also scored hits on military and economic infrastructure deep in the Russian heartland, extending its reach to St Petersburg for the first time. Ukrainian military intelligence said it had struck an unspecified military target in St Petersburg on Thursday, using drones launched from Ukrainian soil. Ukrainian strategic industries minister Oleksandr Kamyshin confirmed the attack, telling the World Economic Forum in Davos that the attack was carried out by a Ukrainian-built drone that had travelled 1,250km (780 miles) from Ukrainian soil. Russia's defence ministry said three drones had been launched and it had downed all three over the Gulf of Finland that day, one near an oil terminal. On Sunday, Ukraine attacked again in several locations, and this time, the evidence of its success was clear.


Precise Robotic Weed Spot-Spraying for Reduced Herbicide Usage and Improved Environmental Outcomes -- A Real-World Case Study

arXiv.org Artificial Intelligence

Precise robotic weed control plays an essential role in precision agriculture. It can help significantly reduce the environmental impact of herbicides while reducing weed management costs for farmers. In this paper, we demonstrate that a custom-designed robotic spot spraying tool based on computer vision and deep learning can significantly reduce herbicide usage on sugarcane farms. We present results from field trials that compare robotic spot spraying against industry-standard broadcast spraying, by measuring the weed control efficacy, the reduction in herbicide usage, and the water quality improvements in irrigation runoff. The average results across 25 hectares of field trials show that spot spraying on sugarcane farms is 97% as effective as broadcast spraying and reduces herbicide usage by 35%, proportionally to the weed density. For specific trial strips with lower weed pressure, spot spraying reduced herbicide usage by up to 65%. Water quality measurements of irrigation-induced runoff, three to six days after spraying, showed reductions in the mean concentration and mean load of herbicides of 39% and 54%, respectively, compared to broadcast spraying. These promising results reveal the capability of spot spraying technology to reduce herbicide usage on sugarcane farms without impacting weed control and potentially providing sustained water quality benefits.


Traffic Learning and Proactive UAV Trajectory Planning for Data Uplink in Markovian IoT Models

arXiv.org Artificial Intelligence

The age of information (AoI) is used to measure the freshness of the data. In IoT networks, the traditional resource management schemes rely on a message exchange between the devices and the base station (BS) before communication which causes high AoI, high energy consumption, and low reliability. Unmanned aerial vehicles (UAVs) as flying BSs have many advantages in minimizing the AoI, energy-saving, and throughput improvement. In this paper, we present a novel learning-based framework that estimates the traffic arrival of IoT devices based on Markovian events. The learning proceeds to optimize the trajectory of multiple UAVs and their scheduling policy. First, the BS predicts the future traffic of the devices. We compare two traffic predictors: the forward algorithm (FA) and the long short-term memory (LSTM). Afterward, we propose a deep reinforcement learning (DRL) approach to optimize the optimal policy of each UAV. Finally, we manipulate the optimum reward function for the proposed DRL approach. Simulation results show that the proposed algorithm outperforms the random-walk (RW) baseline model regarding the AoI, scheduling accuracy, and transmission power.


Survey of Simulators for Aerial Robots

arXiv.org Artificial Intelligence

Uncrewed Aerial Vehicle (UAV) research faces challenges with safety, scalability, costs, and ecological impact when conducting hardware testing. High-fidelity simulators offer a vital solution by replicating real-world conditions to enable the development and evaluation of novel perception and control algorithms. However, the large number of available simulators poses a significant challenge for researchers to determine which simulator best suits their specific use-case, based on each simulator's limitations and customization readiness. This paper includes a systematic overview of 38 existing UAV simulators and presents a set of decision factors for their selection, aiming to enhance the efficiency and safety of research endeavors.


Israel's rising use of drone strikes in the occupied West Bank

Al Jazeera

"It's illegal, and the world should be holding Israel to account." Israel's increase in the use of drone warfare in the occupied West Bank is being condemned by lawyers and rights activists. Al Jazeera spoke to lawyer Diana Buttu about the concerns raised and what can be done to hold Israel accountable.


Ohio Republican Senate candidates clash over border security, drone strikes in Mexico

FOX News

Ohio Republican candidates who are vying to take on Democratic incumbent Sen. Sherrod Brown clashed over border security and drone strikes in Mexico during Monday's first statewide debate. Facing off at WJW Fox 8 Studios in Cleveland, businessman Bernie Moreno, Ohio Secretary of State Frank LaRose and state Sen. Matt Dolan generally agreed on a few issues, including calling for fully securing the U.S.-Mexico border, but then quickly clashed upon delving into the immigration crisis further. Dolan accused Moreno, who was endorsed by former President Trump, of wanting "to militarize the federal government and deport children" for his stance calling for deporting anybody in the country illegally. LaRose called earlier Monday for President Biden to deploy three military divisions to the border, which Dolan said was irresponsible. "We need to work with the Mexican government, we need to be tough with the Mexican government," Dolan said.