Grasping, Perching, And Visual Servoing For Micro Aerial Vehicles

Micro Aerial Vehicles (MAVs) have seen a dramatic growth in the consumer market because of their ability to provide new vantage points for aerial photography and videography. However, there is little consideration for physical interaction with the environment surrounding them. Onboard manipulators are absent, and onboard perception, if existent, is used to avoid obstacles and maintain a minimum distance from them. There are many applications, however, which would benefit greatly from aerial manipulation or flight in close proximity to structures. This work is focused on facilitating these types of close interactions between quadrotors and surrounding objects. We first explore high-speed grasping, enabling a quadrotor to quickly grasp an object while moving at a high relative velocity. Next, we discuss planning and control strategies, empowering a quadrotor to perch on vertical surfaces using a downward-facing gripper. Then, we demonstrate that such interactions can be achieved using only onboard sensors by incorporating vision-based control and vision-based planning. In particular, we show how a quadrotor can use a single camera and an Inertial Measurement Unit (IMU) to perch on a cylinder. Finally, we generalize our approach to consider objects in motion, and we present relative pose estimation and planning, enabling tracking of a moving sphere using only an onboard camera and IMU

Optimal Path Finding With Beetle Antennae Search Algorithm by Using Ant Colony Optimization Initialization and Different Searching Strategies

Intelligent algorithm acts as one of the most important solutions to path planning problem. In order to solve the problems of poor real-time and low accuracy of the heuristic optimization algorithm in 3D path planning, this paper proposes a novel heuristic intelligent algorithm derived from the Beetle Antennae Search (BAS) algorithm. The algorithm proposed in this paper has the advantages of wide search range and high search accuracy, and can still maintain a low time complexity when multiple mechanisms are introduced. This paper combines the BAS algorithm with three non-trivial mechanisms proposed to solve the problems of low search efficiency and poor convergence accuracy in 3D path planning. The algorithm contains three non-trivial mechanisms, including local fast search, aco initial path generation, and searching information orientation. At first, local fast search mechanism presents a specific bounded area and add fast iterative exploration to speed up the convergence of path finding. Then aco initial path generation mechanism is initialized by Ant Colony Optimization (ACO) as a pruning basis. The initialization of the ACO algorithm can quickly obtain an effective path. Using the exploration trend of this path, the algorithm can quickly obtain a locally optimal path. Thirdly, searching information orientation mechanism is employed for BAS algorithm to guarantee the stability of the path finding, thereby avoiding blind exploration and reducing wasted computing resources. Simulation results show that the algorithm proposed in this paper has higher search accuracy and exploration speed than other intelligent algorithms, and improves the adaptability of the path planning algorithms in different environments. The effectiveness of the proposed algorithm is verified in simulation

Bioinspired Control of Rudderless Morphing UAVs

Morphing to seamlessly alter aircraft geometry for either multi-mission or adaptive fly-by-feel flight has recently become an emerging field of research. With the added benefits of tailored aerodynamics, an aircraft no longer needs to be designed to suit a single cruise flight condition. This is particularly useful for small Unmanned Aerial Vehicles (UAVs) which, like birds and insects, tend to operate at lower altitudes and even in urban environments where the flow can frequently change drastically. The primary objective of this research is to investigate morphing applications for rudderless UAVs, which have seldom been studied prior to this point, through bioinspiration. As natural fliers undergo multi-scale low-altitude morphing to adapt to changes in either flight objective or aerodynamic conditions, they are prime subjects for investigation. This is accomplished through both analytical aerodynamic modeling, and experimental design and investigation of novel morphing actuators using Macro Fiber Composites (MFCs). Using these smart material actuators, complex shape change such as spanwise camber morphing and three-dimensional bending-twisting coupling is achieved. This dissertation presents three main contributions to the field of morphing aircraft. The first contribution is an analytical derivation that assesses the impact of scale and altitude on flight. This is aimed at justifying the need for morphing technologies particularly at the UAV scale by assessing the impact of winds on flight velocity and direction. More specifically, both a steady wind and a quasi-steady sharp-edge cross wind were assessed to characterize the response, and showed that low-altitude fliers are prone to drastic changes in flight path, acceleration, and sensitivity with respect to winds. A nonlinear Lifting Line Theory (LLT) model was also developed specifically for spanwise morphing aircraft. With this model, the spanwise geometry of a morphing wing can be tailored and optimized to achieve a desired aerodynamic outcome. As this model is capable of characterizing nonlinear aerodynamics, the spanwise wing geometry is tailored to recover from stall. A comprehensive analysis of possible adaptation scenarios is also conducted to characterize the limitations of the system and demonstrated excellent recovery capabilities of the spanwise morphing wing. Lastly, a novel bioinspired tail actuator is developed for multifunctional pitch and yaw control using MFCs. Two Finite Element Method (FEM) models are compared to determine both an appropriate method of modeling MFC actuators with custom non-rectangular geometries and fiber orientations, and the optimal fiber orientation to obtain adequate transverse and out-of-plane displacements. The optimized actuator was integrated into a bioinspired aircraft for wind tunnel testing. Experimental investigation was geared towards quantifying both pitch and yaw response of the actuator with respect to both changes in angle of attack and sideslip.PHDAerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/145843/1/llgamble_1.pd

Advances in Artificial Intelligence: Models, Optimization, and Machine Learning

The present book contains all the articles accepted and published in the Special Issue “Advances in Artificial Intelligence: Models, Optimization, and Machine Learning” of the MDPI Mathematics journal, which covers a wide range of topics connected to the theory and applications of artificial intelligence and its subfields. These topics include, among others, deep learning and classic machine learning algorithms, neural modelling, architectures and learning algorithms, biologically inspired optimization algorithms, algorithms for autonomous driving, probabilistic models and Bayesian reasoning, intelligent agents and multiagent systems. We hope that the scientific results presented in this book will serve as valuable sources of documentation and inspiration for anyone willing to pursue research in artificial intelligence, machine learning and their widespread applications

Avian Behavioral and Physiological Responses to Challenging Thermal Environments and Extreme Weather Events

Birds occupy habitats ranging from Antarctic ice shelves and Arctic tundra to low-latitude deserts and lowland rainforests, and so are exposed to the full range of climates present on Earth. Cold, hot, or variable (on a variety of temporal scales) thermal conditions can present significant thermoregulatory challenges to birds, which typically must maintain body temperatures within narrow physiological tolerance limits. Such challenges may occur in all stages of the annual cycle and in all life stages of birds, so the ability to adjust to these conditions is required to maintain stable populations through time. For this Research Topic, we broadly define a challenging thermal environment as one necessitating behavioral or physiological adjustments to maintain body temperatures at levels appropriate for continued physiological function.Avian abilities to respond to extreme cold and heat are defined by thermoregulatory capacities for heat production or dissipation, respectively. Behavioral responses to temperature challenges can reduce the necessity for and magnitude of physiological adjustments, so together, physiological capacities and behavioral responses determine the probability of survival in thermally challenging situations. Moreover, thermal conditions experienced during reproduction can affect parental investment in the nesting effort and, independently, alter the course of nestling development, with potentially long-term consequences. Behavioral responses to these conditions as well as physiological responses at multiple levels of organization, from organisms to molecules, allow birds to tolerate thermal challenges. Our knowledge of the mechanisms by which birds respond, the time course for such responses, and the impacts on fitness, however, remain incompletely understood. Studies examining behavioral and physiological responses of birds to extreme and/or seasonally variable climates have been a research focus for decades, but recent advances in methods of measurement and analyses of physiological and behavioral traits have led to novel findings regarding the patterns and mechanisms by which birds adjust to challenging thermal environments.This Research Topic examines how thermal conditions in the environment pose challenges to birds and the physiological and behavioral adjustments that birds employ to meet them. Articles for this Research Topic may be original research papers, reviews, or perspectives. Specific themes that we believe are suitable for this Research Topic include, but are not limited to:• Integrative mechanisms underlying bird thermoregulatory capacities contributing to a tolerance of challenging thermal environments and their links to fitness• Influence of thermal conditions during reproduction on parental investment or nestling development• Behavioral responses to challenging thermal conditions and their mechanistic underpinnings• Time courses for physiological adjustments to environmental temperature variation• Physiological and behavioral flexibility associated with daily or seasonal temperature variation• Physiological and behavioral responses and tolerance limits during extreme weather events• Body temperature regulation under challenging thermal conditions and energy or water restrictions, including real-time field measurements and thermal imaging• Body temperature regulation and environmental or ecological drivers of hypometabolic strategies• Physiological consequences of exceeding thermoregulatory capacitie

The Hidden Forms And Functions Of Courtship In The Brown-Headed Cowbird (molothrus Ater)

Reproductive fitness is the result of complex interacting processes, however our understanding of reproduction is often limited to a few, static male traits. While conspicuous male traits are very well studied, female behavior has received far less attention. Furthermore, conspicuous male traits often fail to predict reproductive success, suggest that there are other important aspects of sexual behavior, however what these factors are or how they interact remains largely unknown. Brown-headed cowbirds (Molothrus ater) breed readily in captivity and their copulatory behavior can be evoked under carefully controlled experimental conditions. By pairing many years of behavioral observations with careful analysis and quantification of behavior, I identified several mechanisms guiding courtship and reproduction. Female copulation is directly evoked by male song, and the strength of the copulatory display reflects signal strength. Interestingly, the copulatory display is mediated by the variable behavioral state of the female, suggesting that song alone is insufficient to elicit copulation. Flocks also display measurable cohesion in the timing of their behavior, transitioning as a group between singing to males and singing to females, and the strength of this group cohesion predicts reproductive success for both individuals and the group as a whole. This work shows that reproductive fitness is far richer than just the quality of male signals and provides a platform to understand the rich complexity of animal courtship