Hasil untuk "Control engineering systems. Automatic machinery (General)"

Nathan P. Lawrence, Philip D. Loewen, M. Forbes et al.

Reinforcement learning (RL) and model predictive control (MPC) offer a wealth of distinct approaches for automatic decision-making under uncertainty. Given the impact both fields have had independently across numerous domains, there is growing interest in combining the general-purpose learning capability of RL with the safety and robustness features of MPC. To this end, this paper presents a tutorial-style treatment of RL and MPC, treating them as alternative approaches to solving Markov decision processes. In our formulation, RL aims to learn a global value function through offline exploration in an uncertain environment, whereas MPC constructs a local value function through online optimization. This local-global perspective suggests new ways to design policies that combine robustness and goal-conditioned learning. Robustness is incorporated into the RL and MPC pipelines through a scenario-based approach. Goal-conditioned learning aims to alleviate the burden of engineering a reward function for RL. Combining the two leads to a single policy that unites a robust, high-level RL terminal value function with short-term, scenario-based MPC planning for reliable constraint satisfaction. This approach leverages the benefits of both RL and MPC, the effectiveness of which is demonstrated on classical control benchmarks.

Abolfazl Hashemi

Calculating fixed points of a nonlinear function is a central problem in many areas of science and engineering with applications ranging from the study of dynamical systems to optimization and game theory. Fixed-point iteration methods provide a simple way to calculate the fixed point of nonexpansive mappings and they have been studied extensively. Emerging applications, however, necessitate the study of fixed-point calculation under various perturbations. For instance, in the data-driven identification of dynamical systems, the learning is typically erroneous, which in turn impacts the subsequent fixed calculations, which itself is an essential step for control. Motivated by such settings, in this work, we establish a general mathematical modeling framework for the study of inexact fixed-point iteration (FPI) algorithms. In doing so, we leverage and extend the recent advances in the stochastic optimization literature to derive new methods and convergence analysis results. In particular, adopting this view enables us to present a unified mathematical model to study the impact of inexact computations in both expansive and nonexpansive scenarios, a new technical approach for the analysis of inexact FPI methods, and a new inexact FPI method, which under certain assumptions, enjoys a faster convergence rate than traditional FPI algorithms in the expansive case.

Jingang Han, Zhihan Chen, Jingwu Sun

With the development of the High Voltage Direct Current (HVDC) technology, the audible sharp noise originated by the AC filter capacitors has become a serious noise pollution problem in HVDC converter stations. However, the harsh and complex operating conditions of power capacitors in converter stations make on-site noise analysis and testing extremely challenging. Therefore, this strategy focuses on three key aspects: (1) accurately simulating real operating conditions, (2) synchronizing fundamental and harmonic currents, and (3) fast and precise harmonic current detection and control. In this paper, a Multiple Harmonic Current Injection System (MHCIS) is proposed to simulate the actual working conditions of power capacitors in HVDC converter stations. Accurate and fast harmonic current detection, along with fundamental-harmonic synchronization, are critical for MHCIS. First, a comparative survey about the performance among Single-Phase Locked Loops based on the Orthogonal Signal Generation (OSG-SPLL) is presented, then a new SPLL strategy based on the Arbitrary Phase Delay (APD-SPLL) is proposed. A Multiple Synchronous Reference Frame (MSRF) combined with the Moving Average Filter (MAF) is applied to detect and control the selective harmonic current in MHCIS. Finally, both simulations and experiments demonstrate the effectiveness of the MHCIS introduced in this paper.

Bin Fang, Jie Zhao, Nailong Liu et al.

Marker‐type vision‐based tactile sensors (VTS) realize force sensing by calibrating marker vector information. The tactile visualization can provide high‐precision and multimodal force information to promote robotic dexterous manipulation development. Considering VTS's contribution to force measurement, this article reviews the advanced force measurement technologies of VTSs. First, the working principle of marker‐type VTSs is introduced, including single‐layer markers, double‐layer markers, color coding, and optical flow. Then, the relationship between the marker type and the category of force measurement is discussed in detail. On this basis, the process of marker feature extraction is summarized, including image processing and marker‐matching technologies. According to the learning approach, force measurement methods are classified into physical and deep learning models. Further, branches of each method are analyzed in terms of input types. Combined with measuring range and precision, the correlation of sensor design, materials, and recognition methods to force measurement performance is further discussed. Finally, the difficulties and challenges are analyzed, and future developments are proposed. This review aims to deepen understanding of the research progress and applications and provide a reference for the research community to promote technology generations in related fields.

M. Civera, Vezio Mugnaini, L. Zanotti Fragonara

Structural health monitoring (SHM) is one of the main research topics in civil, mechanical and aerospace engineering. In this regard, modal parameters and their trends over time can be used as features and indicators of damage occurrence and growth. However, for practical reasons, output‐only techniques are particularly suitable for the system identification (SI) of large civil structures and infrastructures, as they do not require a controlled source of input force. In this context, these approaches are typically referred to as operational modal analysis (OMA) techniques. However, the interpretation of the OMA identifications is a labour‐intensive task, which could be better automated with artificial intelligence and machine learning (ML) techniques. In particular, clustering and cluster analysis can be used to group unlabelled datasets and interpret them. In this study, a novel multi‐stage clustering algorithm for automatic OMA (AOMA) is tested and validated for SHM applications—specifically, for damage detection and severity assessment—to a masonry arch bridge. The experimental case study involves a 1:2 scaled model, progressively damaged to simulate foundation scouring at the central pier.

Shuyuan Zhang, Lei Wang, Bai Xue et al.

This article is concerned with consensus for heterogeneous multiagent systems under distributed nonlinear control protocol. Based on general Lyapunov functions beyond the quadratic form, a less conservative consensus criterion is proposed in the presence of only a directed spanning tree. Then, the consensus problem for polynomial systems can be converted into a sum-of-squares programming problem, yielding polynomial Lyapunov functions efficiently to realize the consensus criterion verification. The benefits of our method are twofold. One is the automatic verification of consensus for the heterogeneous multiagent systems, for which the widely used quadratic Lyapunov functions may not exist. The other one is the flexible generalization ability to deal with certain nonpolynomial multiagent systems. Finally, the theoretical and algorithmic developments are demonstrated on three numerical examples.

Wangli Hao, Li Zhang, Shu-ai Xu et al.

Accurate and efficient livestock detection and counting are crucial for agricultural intelligence. To address the obstacles created by traditional manual methods and limitations of current vision technology, we introduce YOLOv5-MHSA-DS, a novel model that integrates YOLOv5 framework with Multi-Head Self-Attention and DySample modules. Multi-Head Self-Attention excels at capturing diverse features, enhancing pig detection and counting accuracy. On the other hand, DySample dynamically adjusts sampling strategies based on input data, allowing it to focus on the most critical parts of the image and thereby significantly improving pig detection and counting performance. To validate the generalization and robustness of our proposed model, we conducted ablation experiments. The results demonstrate that YOLOv5-MHSA-DS achieves an impressive mAP of 93.8% and counting accuracy of 95.0%, surpassing other models by significant margins of 12.2% and 19.0%, respectively.

Hafiz Ahsan Said, Demian Garcia-Violini, Nicolas Faedo et al.

Optimal control of wave energy converters (WECs), while converting wave energy into a usable form, such as electricity, may <italic>inject</italic> (reactive) power into the system at various points in the wave cycle. Though somewhat counter-intuitive, this action usually results in improved overall energy conversion. However, recent experimental results show that, on occasion, reactive power peaks can be significantly in excess of active power levels, leaving device developers with difficult decision in how to rate the power take-off of the system i.e. whether to cater for these high reactive power peaks, or limit power flow to rated (active) levels. The origins of these excessive power peaks are currently poorly understood, creating significant uncertainty in how to deal with them. In this paper, we show that, using both theoretical results and an illustrative simulation case study, <italic>under matched controller conditions</italic> (impedance-matching optimal condition), for both monochromatic and panchromatic sea-states, that the maximum peak reactive/active power ratio <italic>never exceeds unity</italic>. However, under mismatched WEC/controller conditions, this peak power ratio can exceed unity, bringing unrealistic demands on the power take-off (PTO) rating. The paper examines the various origins of system/controller mismatch, including modelling error, controller synthesis inaccuracies, and non-ideal PTO behaviour, highlighting the consequences of such errors on reactive power flow levels. This important result points to the need for accurate WEC modeling, while also showing the folly of catering for excessive reactive power peaks.

G. Rață, M. Rață

The purpose of the automatic transfer switching (ATS) is to swiftly replace the basic power supply with the standby power supply in the event of a loss or excessive reduction of the voltage in the primary power path, with simultaneous full efficiency of the back-up power supply devices. ATS automation is aimed at improving the reliability of the electricity supply. In this paper the authors present a hardware and software application used to study how to operate an ATS controlled by a PLC-HMI system, useful for engineers and master's students in the field of electrical engineering.

LIU Yue, LUO Xiao, CHU Wei et al.

In order to develop more intelligent transport vehicles for surface mines to enable the drivers work more efficiently and safely, this paper puts forward a solution of applying voice technology to the cab of mine transport vehicle and ground command center. This approach encompasses an array of functions, including noise reduction based on array microphone pickup, voice wake-up, speech recognition, and speech synthesis. Relying on the on-board display platform and ground server platform, two modules were developed respectively for voice interaction and voice broadcasting, to enable keyword recognition and emergency broadcasting of dangerous situations. According to the results of laboratory test and field test at mines, the application of this solution managed to meet the echo suppression effect of 20 dB reduction in the cab, and control the bottom noise of spectrograms within 200-300 sample, meeting the subsequent demand for audio quality recognition; the model demonstrated a recognition accuracy greater than 85% and a real-time rate less than 500 ms, in the normal on-board environment and at a pickup distance of 80 cm. The results verifies that the functions and performances of the voice noise reduction, speech recognition and speech synthesis meet the technical requirements for mine transport vehicles, and shows that the application of voice technology improves the convenience of interaction between drivers and vehicle equipment and the timeliness of warning in dangerous situations.

Holger Waubke, Christian H Kasess

Previously, it was shown how the behavior of chain-like structures including hysteretic elements as described by the Bouc model under white noise excitation can be calculated using Gaussian closure. The method results in analytic expressions for the temporal evolution of the statistical moments. Using the example of a liquid-filled tank, the Gaussian closure is generalized to the case of a filtered white noise with a slowly varying intensity as may occur during earthquakes. The complexity of the model is further enhanced for a case that lacks an elastic restoring force at the hysteretic node that couples the tank model with the surface. The new tank model comprises three mechanical degrees of freedom. The first degree of freedom is the movement of mass of the tank. The second degree of freedom is the movement of the swapping mass of the fluid in the tank. The third degree of freedom is the movement of the impulsive mass that is coupled more stiffly.

Jing Wang

The technology for multiple-noise removal has triggered skyrocketing interest in both mathematics and engineering, and the tropical algebra has laid the foundation for an abundance of noise filters. However, the denoising of the filter based on the traditional algebra is inextricably complex, and its algorithm is extremely intricate and awfully inefficient, so it is necessary to estimate the statistical characteristics of noise in a novel way. Now the tropical algebra has opened the path for a new way to design optimally a denoising method, which has obvious advantages over traditional ones in denoising efficiency and simple filtering algorithm. In this paper, the idempotent of the multiplicative semigroup of 4 × 4 tropical matrices is studied. First, the tropical algebra and the tropical matrix multiplicative semigroup are introduced. Second, the idempotent classification of the 4 × 4 tropical matrix multiplicative semigroup is given. Finally, an example is given, in which the filter based on tropical algebra is used for denoising, and an optimization method with tropical polynomials as constraints is given.

Guangdeng Zong, Hangli Ren

In this paper, the guaranteed cost finite‐time control for semi‐Markov jump systems with unknown transition rates is addressed. An event‐triggered scheme is constructed to automatically monitor the data transmission and the input quantization is involved to reduce the cost of control. Different from the existing general transition rates in the semi‐Markov jump systems, the upper and lower bounds of transition rates are not given in advance but obtained through the stability criteria. The stability criteria are established to verify the stochastic finite‐time boundedness of the closed‐loop event‐triggered system and estimate the performance index of the given cost function. A guaranteed cost optimal controller is also proposed to stabilize the considered system. Finally, the vertical take‐off and landing helicopter model is introduced to verify the effectiveness of the main algorithms.

Taegyu Kim, Aolin Ding, Sriharsha Etigowni et al.

Unmanned Aerial Vehicles as a service (UAVaaS) has increased the field deployment of Robotic Aerial Vehicles (RAVs) for different services such as transportation and terrain exploration. These RAVs are controlled by firmware, which is often closed-source, developed by vendors, and flashed into the ROM. While these binary blobs enable off-the-shelf management of RAVs, end users (individuals or organizations) have no idea if the control firmware is designed and implemented correctly, and can only rely on firmware updates from vendors when any vulnerability is discovered. This paper proposes DisPatch, the first reverse engineering and patching framework for understanding and improving controller design and implementation within RAV firmware. DisPatch first decompiles binary instructions and recovers controller functions and core controller variables by combining control theory with program analysis using symbolic execution and data flow analysis. End users can then write a patch in a domain-specific language (DSL), which will be translated and injected into the binary firmware by DisPatch automatically. We have applied DisPatch to two instances of commodity firmware from3DR IRIS+ and MantisQ RAVs and demonstrated 100% and 80.7% accuracy respectively in the controller decompilation. We have also shown the ability to prevent severe controller performance degradation by patching two real-world bugs with in the firmware and without breaking other functionality. Finally, we show that DisPatch introduces less than 0.53% of space overhead and 1.48% of runtime overhead without violating the soft real-time deadlines. DisPatch provides the first step towards an RAV binary firmware reverse engineering and patching system to customize controller design and implementation.

Grischa Liebel, E. Knauss

Using models for requirements engineering (RE) is uncommon in systems engineering, despite the widespread use of model-based engineering in general. One reason for this lack of use is that formal models do not match well the trend to move towards agile developing methods. While there exists work that investigates challenges in the adoption of requirements modeling and agile methods in systems engineering, there is a lack of work studying successful approaches of using requirements modelling in agile systems engineering. To address this gap, we conducted a case study investigating the application of requirements models at Ericsson AB, a Swedish telecommunications company. We studied a department using requirements models to bridge agile development and plan-driven development aspects. We find that models are used to understand how requirements relate to each other, and to keep track with the product's evolution. To cope with the effort to maintain models over time, study participants suggest to rely on text-based notations that bring the models closer to developers and allow integration into existing software development workflows. This results in tool trade-offs, e.g., losing the possibility to control diagram layout.

Yanjie Jiang, Hui Liu, Nan Niu et al.

High-quality and large-scale repositories of real bugs and their concise patches collected from real-world applications are critical for research in software engineering community. In such a repository, each real bug is explicitly associated with its fix. Therefore, on one side, the real bugs and their fixes may inspire novel approaches for finding, locating, and repairing software bugs; on the other side, the real bugs and their fixes are indispensable for rigorous and meaningful evaluation of approaches for software testing, fault localization, and program repair. To this end, a number of such repositories, e.g., Defects4J, have been proposed. However, such repositories are rather small because their construction involves expensive human intervention. Although bug-fixing code commits as well as associated test cases could be retrieved from version control systems automatically, existing approaches could not yet automatically extract concise bug-fixing patches from bug-fixing commits because such commits often involve bug-irrelevant changes. In this paper, we propose an automatic approach, called BugBuilder, to extracting complete and concise bug-fixing patches from human-written patches in version control systems. It excludes refactorings by detecting refactorings involved in bug-fixing commits, and reapplying detected refactorings on the faulty version. It enumerates all subsets of the remaining part and validates them on test cases. If none of the subsets has the potential to be a complete bug-fixing patch, the remaining part as a whole is taken as a complete and concise bug-fixing patch. Evaluation results on 809 real bug-fixing commits in Defects4J suggest that BugBuilder successfully generated complete and concise bug-fixing patches for forty percent of the bug-fixing commits, and its precision (99%) was even higher than human experts.

Shubham Sutar, Dhiraj Palkar, R. Karche et al.

Abstract: Motorcycles are widely used around the world particularly in INDIA. The gear shifting system of the motor-cycle is conventionally manual. This report covers development of an indigenous gear shifting /changing system for the standard motorcycle. By this system the manual mechanical gear- shifting will remain unchanged because an additional electromechanical system is placed on the top of the lever to shift the gear and automatically control the clutch. So the system has both the option manual as well as automatic. The system uses low cost microcontrollers to make the accurate decision for shifting the gear up and down by observing the speed, and it controls the clutch transmission where necessary. The complete hardware and software has been tested and the functioning of the automatic gear shifting system is verified. System is flexible and can be used with any motorcycle ranging from 50 to 200 cc. General Terms Automation. Keywords Linear Actuator, Arduino, Hall effect sensor, Atmega328, Servo motor, Gear shift lever

Wenjuan He

The embedded English speech teaching recognition system is a technology that writes the English speech recognition device control program into the chip and embeds the chip into the device, so that the human-like chip controls the English speech device to complete the speech recognition operation. Applying the embedded technology to the English speech recognition system can improve the recognition accuracy of the system to a higher level in terms of recognizing the English speech of a specific person. The purpose of this paper is to research and design an automatic error detection method for embedded English speech teaching recognition system in the context of artificial intelligence. This paper first gives a general introduction to the overview of artificial intelligence, then analyzes the speech recognition algorithm, uses MatLab software to obtain the correct number of recognition system words and the correct rate, and then implements the embedded English teaching recognition system in different environments. The experimental results of comparison through multiple test analysis show that in a quiet environment, the error rate of the embedded English speech teaching recognition system is very low, and the correct recognition rate can reach more than 90%. In a noisy environment affected by various noises, the correct recognition rate of the embedded English speech teaching recognition system is basically above 60%.

Zack Kirkendoll

YAN Meng, FU Liang, ZHA Guotao et al.

Micro perforation plate (MPP) sound liner is a very effective method to control pipe noise in high-speed airflow environment based on the principle of Helmholtz resonator. It generally has single layer, double-layer or even multi-layer structure. At present, the acoustic design theory of MPP sound liner is mature and reliable in the absence of air flow, but the design process is complicated in the presence of air flow, especially in the environment of high-speed air flow, and there are many influencing factors, so it has not formed a mature and unified theoretical basis for design. In this paper, an acoustic impedance model of double-layer MPP sound liner with two resonant frequencies is derived which is based on the acoustic impedance model of single layer MPP sound liner by the transfer matrix method (TMM). The model is used to calculate acoustic impedance and acoustic absorption of a known double-layer MPP sound liner at 130 dB sound intensity level and 60 m/s velocity. At the same time, the flow tube method is used for measurement. The results show that the theoretical results are close to the measured results. The maximum error of sound absorption coefficient is only 0.05, which can meet the requirements of engineering application.