control barrier functions (CBFs) have been widely applied to safety-critical robotic applications. However, the construction of control barrier functions for robotic systems remains a challenging task. Recently, colli...
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—Trajectory planning for quadrotors in cluttered environments has been challenging in recent years. While many trajectory planning frameworks have been successful, there still exists potential for improvements, parti...
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—Trajectory planning for quadrotors in cluttered environments has been challenging in recent years. While many trajectory planning frameworks have been successful, there still exists potential for improvements, particularly in enhancing the speed of generating efficient trajectories. In this paper, we present a novel hierarchical trajectory planning framework to reduce computational time and memory usage called MINER-RRT*, which consists of two main components. First, we propose a sampling-based path planning method boosted by neural networks, where the predicted heuristic region accelerates the convergence of rapidly-exploring random trees. Second, we utilize the optimal conditions derived from the quadrotor’s differential flatness properties to construct polynomial trajectories that minimize control effort in multiple stages. Extensive simulation and real-world experimental results demonstrate that, compared to several state-of-the-art (SOTA) approaches, our method can generate high-quality trajectories with better performance in 3D cluttered environments. (Video1) Note to Practitioners—The motivation is the problem of planning trajectories for quadrotor autonomous flight in 3D cluttered and complex scenarios such as wild forest exploration and subterranean environment search-and-rescue. Sampling-based path planning methods are suitable for dealing with the complexity of the physical environment but are not convenient for computing dynamics and their differentials. Optimization-based trajectory generation methods are appropriate for handling various high-order constraints but rely on high-quality initial path solutions. Therefore, this paper combines the advantages of the two methods to propose a novel trajectory planning framework that can generate high-quality trajectories for quadrotors faster than many previous algorithms. We conduct numerous simulations and real-world experiments to verify that our method can be effectively deployed in real scenarios and empo
The paper presents the schemes for manufacturing a microoptoelectromechanical (MOEM) accelerometer for measuring small accelerations. MOEM-accelerometer includes three subsystems: mechanical, optical and electronic. T...
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ISBN:
(纸本)9781665476287
The paper presents the schemes for manufacturing a microoptoelectromechanical (MOEM) accelerometer for measuring small accelerations. MOEM-accelerometer includes three subsystems: mechanical, optical and electronic. The mechanical subsystem includes an inertial body, mounted on a spring suspension in a case. The optical subsystem includes a laser, moving and fixed waveguides. The electrical subsystem includes a photodiode and electronic components. To measure microdisplacements that correspond to measured microaccelerations, an optical system based on the optical tunnel effect was used. The work considers the schemes of the optical transducer for linear and angular displacements of the mechanical subsystem. The moving waveguide together with the inertial body are combined into the mechanical sensing element that diverges in the case of acceleration. A technological process for manufacturing a MOEM accelerometer based on the 'silicon on insulator' technology with additional layers of nitride and silicon oxide for optical functional elements is presented. Depending on the character of the movement of the sensing element, the functional schemes of the MOEM-accelerometer were developed with various changeable parameters: optical coupling length, gap, overlapping area between the moving and fixed waveguides. The article analyzes the advantages and drawbacks of the proposed schemes of accelerometers from the perspective of their manufacturing feasibility and the predicted accuracy. The highest sensitivity (6.25 × 10-6 m-1) belongs to schemes with changeable gap between the waveguides. The dynamic displacement ranges of them is ± 80 nm. Lower sensitivity (1.25 × 106 m-1) belongs to schemes with changeable overlapping area. The dynamic displacement range may reach ± 300 nm. Schemes with changeable optical coupling length possess the highest dynamic range which directly depends on a chosen optical coupling length and amounts to dozens of microns. The sensitivity of the last
This letter proposes a global navigation satellite system (GNSS) and inertial navigation system (INS)-based, pose estimation method for autonomous vehicles. We focus on the issue of localization in situations where GN...
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In this paper, we introduce a ROS based framework designed for the planning and control of robotic systems within the context of precision agriculture, with an emphasis on human-in-the-loop capabilities. Utilizing Lin...
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ISBN:
(数字)9798350358513
ISBN:
(纸本)9798350358520
In this paper, we introduce a ROS based framework designed for the planning and control of robotic systems within the context of precision agriculture, with an emphasis on human-in-the-loop capabilities. Utilizing Linear Temporal Logic to articulate complex task specifications, our algorithm creates high-level robotic plans that are not only correct by design but also adaptable in real time by human operators. This dual-focus approach ensures that while humans have the flexibility to modify the high-level plan on-the-fly or even take over low-level control of the robots, the system inherently safeguards against any human actions that could potentially breach the predefined task specifications. We demonstrate our algorithm within the dynamic and challenging environment of a real vineyard, where the collaboration between human workers and robots is critical for tasks such as harvesting and pruning, and show the practical applicability and robustness of our software. This work marks a pioneering application of formal methods to complex, real-world agricultural environments.
Sensor network localization (SNL) is a challenging problem due to its inherent non-convexity and the effects of noise in inter-node ranging measurements and anchor node position. We formulate a non-convex SNL problem ...
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Optical applications, such as imaging, communications, and sensing, can be severely limited by the effects of oceanic turbulence when the water is free of particulate matter. To study this phenomenon in a controlled e...
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This paper presents a novel observer-based approach to detect and isolate faulty sensors in nonlinear systems. The proposed sensor fault detection and isolation (s-FDI) method applies to a general class of nonlinear s...
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ISBN:
(数字)9783907144107
ISBN:
(纸本)9798331540920
This paper presents a novel observer-based approach to detect and isolate faulty sensors in nonlinear systems. The proposed sensor fault detection and isolation (s-FDI) method applies to a general class of nonlinear systems. Our focus is on s-FDI for two types of faults: complete failure and sensor degradation. The key aspect of this approach lies in the utilization of a neural network-based Kazantzis-Kravaris/Luenberger (KKL) observer. The neural network is trained to learn the dynamics of the observer, enabling accurate output predictions of the system. Sensor faults are detected by comparing the actual output measurements with the predicted values. If the difference surpasses a theoretical threshold, a sensor fault is detected. To identify and isolate which sensor is faulty, we compare the numerical difference of each sensor measurement with an empirically derived threshold. We derive both theoretical and empirical thresholds for detection and isolation, respectively. Notably, the proposed approach is robust to measurement noise and system uncertainties. Its effectiveness is demonstrated through numerical simulations of sensor faults in a network of Kuramoto oscillators.
We generalize the principle of extension and controller design using this principle for nonlinear systems. We first define principles of inclusion and extension for nonlinear time-invariant (NLTI) systems. Thereafter,...
We generalize the principle of extension and controller design using this principle for nonlinear systems. We first define principles of inclusion and extension for nonlinear time-invariant (NLTI) systems. Thereafter, we present the necessary and sufficient conditions for a system to be an extension of another and show that when the expanded system is an extension of the original system, any controller designed for the expanded system can be contracted for implementation on the original system. Subsequently, we demonstrate how an overlappingly decomposed NLTI system can be expanded so that the expanded system is an extension of the original system, how decentralized controllers can be designed for the expanded system, and how these controllers can be contracted for implementation on the original system. An example is also provided to illustrate the extension and contraction concepts and show controller design using the proposed principles.
Over the past decade, the continuous surge in cloud computing demand has intensified data center workloads, leading to significant carbon emissions and driving the need for improving their efficiency and sustainabilit...
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