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Learning-based Predictive Path Following Control for Nonlinear Systems Under Uncertain Disturbances

arXiv.org Artificial Intelligence

Accurate path following is challenging for autonomous robots operating in uncertain environments. Adaptive and predictive control strategies are crucial for a nonlinear robotic system to achieve high-performance path following control. In this paper, we propose a novel learning-based predictive control scheme that couples a high-level model predictive path following controller (MPFC) with a low-level learning-based feedback linearization controller (LB-FBLC) for nonlinear systems under uncertain disturbances. The low-level LB-FBLC utilizes Gaussian Processes to learn the uncertain environmental disturbances online and tracks the reference state accurately with a probabilistic stability guarantee. Meanwhile, the high-level MPFC exploits the linearized system model augmented with a virtual linear path dynamics model to optimize the evolution of path reference targets, and provides the reference states and controls for the low-level LB-FBLC. Simulation results illustrate the effectiveness of the proposed control strategy on a quadrotor path following task under unknown wind disturbances.


Deep learning-based denoising for fast time-resolved flame emission spectroscopy in high-pressure combustion environment

arXiv.org Artificial Intelligence

A deep learning strategy is developed for fast and accurate gas property measurements using flame emission spectroscopy (FES). Particularly, the short-gated fast FES is essential to resolve fast-evolving combustion behaviors. However, as the exposure time for capturing the flame emission spectrum gets shorter, the signal-to-noise ratio (SNR) decreases, and characteristic spectral features indicating the gas properties become relatively weaker. Then, the property estimation based on the short-gated spectrum is difficult and inaccurate. Denoising convolutional neural networks (CNN) can enhance the SNR of the short-gated spectrum. A new CNN architecture including a reversible down- and up-sampling (DU) operator and a loss function based on proper orthogonal decomposition (POD) coefficients is proposed. For training and testing the CNN, flame chemiluminescence spectra were captured from a stable methane-air flat flame using a portable spectrometer (spectral range: 250 - 850 nm, resolution: 0.5 nm) with varied equivalence ratio (0.8 - 1.2), pressure (1 - 10 bar), and exposure time (0.05, 0.2, 0.4, and 2 s). The long exposure (2 s) spectra were used as the ground truth when training the denoising CNN. A kriging model with POD is trained by the long-gated spectra for calibration, and then the prediction of the gas properties taking the denoised short-gated spectrum as the input: The property prediction errors of pressure and equivalence ratio were remarkably lowered in spite of the low SNR attendant with reduced exposure.


UB3: Best Beam Identification in Millimeter Wave Systems via Pure Exploration Unimodal Bandits

arXiv.org Artificial Intelligence

Millimeter wave (mmWave) communications have a broad spectrum and can support data rates in the order of gigabits per second, as envisioned in 5G systems. However, they cannot be used for long distances due to their sensitivity to attenuation loss. To enable their use in the 5G network, it requires that the transmission energy be focused in sharp pencil beams. As any misalignment between the transmitter and receiver beam pair can reduce the data rate significantly, it is important that they are aligned as much as possible. To find the best transmit-receive beam pair, recent beam alignment (BA) techniques examine the entire beam space, which might result in a large amount of BA latency. Recent works propose to adaptively select the beams such that the cumulative reward measured in terms of received signal strength or throughput is maximized. In this paper, we develop an algorithm that exploits the unimodal structure of the received signal strengths of the beams to identify the best beam in a finite time using pure exploration strategies. Strategies that identify the best beam in a fixed time slot are more suitable for wireless network protocol design than cumulative reward maximization strategies that continuously perform exploration and exploitation. Our algorithm is named Unimodal Bandit for Best Beam (UB3) and identifies the best beam with a high probability in a few rounds. We prove that the error exponent in the probability does not depend on the number of beams and show that this is indeed the case by establishing a lower bound for the unimodal bandits. We demonstrate that UB3 outperforms the state-of-the-art algorithms through extensive simulations. Moreover, our algorithm is simple to implement and has lower computational complexity.


Learning Haptic-based Object Pose Estimation for In-hand Manipulation Control with Underactuated Robotic Hands

arXiv.org Artificial Intelligence

Abstract--Unlike traditional robotic hands, underactuated compliant hands are challenging to model due to inherent uncertainties. Consequently, pose estimation of a grasped object is usually performed based on visual perception. However, visual perception of the hand and object can be limited in occluded or partly-occluded environments. In this paper, we aim to explore the use of haptics, i.e., kinesthetic and tactile sensing, for pose estimation and in-hand manipulation with underactuated hands. Such haptic approach would mitigate occluded environments where line-of-sight is not always available. We put an emphasis on identifying the feature state representation of the system that does not include vision and can be obtained with simple and low-cost hardware. For tactile sensing, therefore, we propose a low-cost and flexible sensor that is mostly 3D printed along with the finger-tip and can provide implicit contact information. Taking a two-finger underactuated hand as a test-case, we analyze the contribution of kinesthetic and tactile features along with various regression models to the accuracy of the predictions. Visual perception is not available within the cabinet and, therefore, the hand must use haptic perception. To cope with the lack of an analytical solution, data-based modeling was shown I. HILE the ability to manipulate an object within the hand is a fundamental everyday task for humans, such intrinsically estimate model parameters that can be difficult problem remains challenging for robots.


Since humans can't manage fusion the US puts millions into AI-powered creation - Embedded House

#artificialintelligence

Some terms and condition may apply Hot off the heels of the US Department of Energy's (DoE) sort-of nuclear fusion breakthrough, the agency is offering up $33 million for researchers that can wrangle artificial intelligence, machine learning, and other data resources to the cause.โ€ฆ


From Mars to Metaverse, as UAE aims high, opportunities open up for India

#artificialintelligence

The year 2022 ends on a positive note with regard to India-UAE relations, with business and political ties between the two countries scaling new heights. The UAE is India's third largest trading partner and the bilateral trade between them surpasses $88 billion. Indians, moreover, constitute 39.9 per cent of the UAE population and their remittances to India add up to more than $17 billion, the largest for any country overseas. To tell the world what the future will be like, Dubai built The Museum Of The Future, which talks about the possibilities of the future. To advance the vision of Sheikh Mohammed bin Rashid Al Maktoum, Ruler of Dubai, to harness the latest technologies in coding, big data analysis, artificial intelligence, virtual and augmented reality, and human-machine interaction to drive the future.


Visual Tactile Sensor Based Force Estimation for Position-Force Teleoperation

arXiv.org Artificial Intelligence

Vision-based tactile sensors have gained extensive attention in the robotics community. The sensors are highly expected to be capable of extracting contact information i.e. haptic information during in-hand manipulation. This nature of tactile sensors makes them a perfect match for haptic feedback applications. In this paper, we propose a contact force estimation method using the vision-based tactile sensor DIGIT, and apply it to a position-force teleoperation architecture for force feedback. The force estimation is done by building a depth map for DIGIT gel surface deformation measurement and applying a regression algorithm on estimated depth data and ground truth force data to get the depth-force relationship. The experiment is performed by constructing a grasping force feedback system with a haptic device as a leader robot and a parallel robot gripper as a follower robot, where the DIGIT sensor is attached to the tip of the robot gripper to estimate the contact force. The preliminary results show the capability of using the low-cost vision-based sensor for force feedback applications.


A Hypervolume Based Approach to Rank Intuitionistic Fuzzy Sets and Its Extension to Multi-criteria Decision Making Under Uncertainty

arXiv.org Artificial Intelligence

Ranking intuitionistic fuzzy sets with distance based ranking methods requires to calculate the distance between intuitionistic fuzzy set and a reference point which is known to have either maximum (positive ideal solution) or minimum (negative ideal solution) value. These group of approaches assume that as the distance of an intuitionistic fuzzy set to the reference point is decreases, the similarity of intuitionistic fuzzy set with that point increases. This is a misconception because an intuitionistic fuzzy set which has the shortest distance to positive ideal solution does not have to be the furthest from negative ideal solution for all circumstances when the distance function is nonlinear. This paper gives a mathematical proof of why this assumption is not valid for any of the non-linear distance functions and suggests a hypervolume based ranking approach as an alternative to distance based ranking. In addition, the suggested ranking approach is extended as a new multicriteria decision making method, HyperVolume based ASsessment (HVAS). HVAS is applied for multicriteria assessment of Turkey's energy alternatives. Results are compared with three well known distance based multicriteria decision making methods (TOPSIS, VIKOR, and CODAS).


A photonic chip-based machine learning approach for the prediction of molecular properties

arXiv.org Artificial Intelligence

Machine learning methods have revolutionized the discovery process of new molecules and materials. However, the intensive training process of neural networks for molecules with ever-increasing complexity has resulted in exponential growth in computation cost, leading to long simulation time and high energy consumption. Photonic chip technology offers an alternative platform for implementing neural networks with faster data processing and lower energy usage compared to digital computers. Photonics technology is naturally capable of implementing complex-valued neural networks at no additional hardware cost. Here, we demonstrate the capability of photonic neural networks for predicting the quantum mechanical properties of molecules. To the best of our knowledge, this work is the first to harness photonic technology for machine learning applications in computational chemistry and molecular sciences, such as drug discovery and materials design. We further show that multiple properties can be learned simultaneously in a photonic chip via a multi-task regression learning algorithm, which is also the first of its kind as well, as most previous works focus on implementing a network in the classification task.


AI in Action: 10 Examples of AI Implementations That Have Improved Our Lives

#artificialintelligence

Artificial intelligence (AI) has made significant progress in recent years, and there are many ways in which it has made life easier for people. From virtual assistants and self-driving cars to AI-powered tutoring systems and smart insulin pumps, AI is being used in a wide range of industries to improve efficiency, personalize services, and solve complex problems. In this article, we will explore 10 AI implementations that have had a positive impact on society, including transportation, health care, education, retail, financial services, agriculture, energy, the environment, disaster response, social media, and space exploration. These examples demonstrate the potential of AI to make our lives easier and more convenient, and they hint at the many ways in which AI may continue to transform our world in the future. AI-powered virtual assistants such as Apple's Siri, Amazon's Alexa, and Google Assistant can help people with tasks such as setting alarms, creating reminders, and answering questions.