External Machine Research Articles

(Invited) Merging Humans and Machines with Hydrogel Bioelectronics

While human tissues are mostly soft, wet and bioactive; machines are commonly hard, dry and biologically inert. Bridging human-machine interfaces is of imminent importance in addressing grand societal challenges in healthcare, security, sustainability and joy of living. However, interfacing human and machines is extremely challenging due to their fundamentally contradictory properties. At MIT SAMs Lab, we propose the Hydrogel Technology to bridge human-machine interfaces. On one side, hydrogels with similar mechanical and physiological properties as tissues can naturally integrate with human body, playing functions such as scaffolds, catheters, stents and implants. On the other side, the hydrogels embedded with electronic and mechanical components can control and respond to external machines. In this talk, I will first discuss the mechanics to design extreme properties for hydrogels, including tough, resilient, adhesive, strong and antifatigue, which are necessary for reliable robust human-machine interfaces. Then I will discuss a set of novel soft hydrogel devices that interface with the human body, including i). long-term high-efficacy hydrogel neural probe, ii). ingestible and GI-resident hydrogel machine, and iii). untethered fast and forceful hydrogel robots controlled by magnetic fields. I will conclude the talk by proposing a systematic approach to design next-generation human-machine interfaces based on hydrogel technology.

Thinking Ahead of the Tractor: Driver Safety and Situation Awareness

ABSTRACTObjective: Situation awareness has been identified as a key skill in maintaining safety in high-risk, dynamic industries. However, there is a lack of research evaluating situation awareness requirements and error types in agricultural operators. The aim of this study was to explore situation awareness among farmers in the United Kingdom (UK) when operating heavy agricultural machinery.Method: The study used an online qualitative survey to collect data in three main areas: situation awareness requirements, factors impacting situation awareness, and the safety context for UK farmers. A total of 57 farmers completed the survey, responding to seven open-ended questions. Data were analyzed using directed content analysis.Results: The results indicate the importance of situation awareness for safe and efficient work practice in farming. Situation awareness requirements span the machinery system, including awareness of internal cab systems and the status of implements attached to the external machine. Farmers needed to map and monitor the surrounding conditions in addition to considering personal requirements. Data also indicated the impact of a range of factors, including system-based elements such as blind spots, individual factors such as level of fatigue, and issues related to a lack of knowledge and failure to think ahead on the maintenance of situation awareness.Conclusion: This research highlights the situation awareness requirements for operating agricultural machinery in complex and dynamic environments. By taking a human factors approach, utilizing design and practical interventions, it may be possible to both support and enhance farmer situation awareness and, therefore, reduce errors and adverse incidents.

A Flexible 5-In-1 Microsensor for Internal Microscopic Diagnosis of Vanadium Redox Flow Battery Charging Process.

Multiple important physical parameters in the vanadium redox flow battery are difficult to measure accurately, and the multiple important physical parameters (e.g., temperature, flow, voltage, current, pressure, and electrolyte concentration) are correlated with each other; all of them have a critical influence on the performance and life of vanadium redox flow battery. In terms of the feed of fuel to vanadium redox flow battery, the pump conveys electrolytes from the outside to inside for reaction. As the performance of vanadium redox flow battery can be tested only by an external machine—after which, the speed of pump is adjusted to control the flow velocity of electrolyte—the optimum performance cannot be obtained. There is a demand for internal real-time microscopic diagnosis of vanadium redox flow batteries, and this study uses micro-electro-mechanical systems (MEMS) technology to develop a flexible five-in-one (temperature, flow, voltage, current, and pressure) microsensor, which is embedded in vanadium redox flow battery, for real-time sensing. Its advantages include: (1) Small size and the simultaneous measurement of five important physical quantities; (2) elastic measurement position and accurate embedding; and (3) high accuracy, sensitivity, and quick response time. The flexible five-in-one microsensor embedded in the vanadium redox flow battery can instantly monitor the changes in different physical quantities in the vanadium redox flow battery during charging; as such, optimum operating parameters can be found out so that performance and life can be enhancec.

Повышение работоспособности твердосплавного режущего инструмента за счет нанесения покрытий

The purpose of the work is to choose the most rational coating for the specified operating conditions of the metal-cutting tool. The rationality is estimated by the operation time until the rear surface wear becomes less than 0.5 mm. The study is given to the influence of coatings on wear resistance of carbide replaceable inserts of turning cutters at the external machining of billets made of stainless specialized hard-working steel of grade 09Х17Н7Ю. The application field of this steel has expanded considerably, while the recommendations for its machining are outdated. As a benchmark for rationality calculation is taken the operation time of domestic carbide plates made of VK8 grade alloy. Consideration is given only to square replaceable carbide inserts with a central base hole, the side length of a square is 12.7 mm. The need for the study is determined by the fact that available recommendations on the processing modes and choice of tool material for this treatment of the specified stainless steel are physically outdated (there are no machines of those models and tool materials). New recommendations are required for modern conditions. An experimental method is used to study the performance of various tool materials (VK8 substrate + a particular coating) by estimating the increase in the amount of tool wear on the rear surface over the time. For the specified operating conditions, a reserve has been created to form a database for the selection of cutting modes and tool materials. The influence of the choice of coating on the increase in tool wear resistance is shown. As a result, the preferred coatings that allow to conduct a lasting processing without cutting edge replacement have been identified. It is determined that the considered tool materials are substantially unequal by their wear resistance. The preferred tool material is VK8 + Ti(up to 1 µm) + TiN(1 µm) + (NbZrTiAl)N(2.5 µm) in which the coating layers are applied by condensation by ion bombardment with droplet filtration and assisting accelerated ions.

A new type of self-powered external cooling shell of air conditioner

In recent years, with the rising demands one indoor comfort, the use of air conditioners is becoming more and more widespread. The energy consumption of air conditioners is rising, accounting for about 40%-60% of the total building energy consumption[1]. During the use of air conditioner in summer, the disordered discharge of condensate water and the excessive temperature of external machine are two major problems that need to be improved. In view of these above problems, we have designed a new type of self_powered external cooling shell of air conditioner. It includes condensate water collection subsystem, solar panel cover subsystem, energy storage subsystem, intelligent control and ultrasonic atomization subsystem. The purpose of this device is to collect the useless air conditioner condensate water and cool down the air conditioner external machine. This device can not only save water, but also enhance the effect of air conditioner refrigeration, save electric energy and enhance the service life of air conditioner.

Brain Computer Interface and its Applications – A Review

Brain Computer Interface(BCI) is a emerging research topic nowadays for researchers. Its significant addition ranging from medical applications to education, research area , marketing, games and entertainment etc. BCI provides a channel between brain of living creature and external machine. It is a process in which brain accepts a mechanical device either by invasive method or non-invasive method as its natural part and by processing of signals, various applications are evolved and created. This paper shows the system of BCI, hardware and software components of BCI with its huge applications like wheelchair, bionic eye, honda’s robot etc. At the end of this paper future work in BCI are discussed.

Affective content analysis of music emotion through EEG

Emotion recognition of music objects is a promising and important research issues in the field of music information retrieval. Usually, music emotion recognition could be considered as a training/classification problem. However, even given a benchmark (a training data with ground truth) and using effective classification algorithms, music emotion recognition remains a challenging problem. Most previous relevant work focuses only on acoustic music content without considering individual difference (i.e., personalization issues). In addition, assessment of emotions is usually self-reported (e.g., emotion tags) which might introduce inaccuracy and inconsistency. Electroencephalography (EEG) is a non-invasive brain-machine interface which allows external machines to sense neurophysiological signals from the brain without surgery. Such unintrusive EEG signals, captured from the central nervous system, have been utilized for exploring emotions. This paper proposes an evidence-based and personalized model for music emotion recognition. In the training phase for model construction and personalized adaption, based on the IADS (the International Affective Digitized Sound system, a set of acoustic emotional stimuli for experimental investigations of emotion and attention), we construct two predictive and generic models \(AN\!N_1\) (“EEG recordings of standardized group vs. emotions”) and \(AN\!N_2\) (“music audio content vs. emotion”). Both models are trained by an artificial neural network. We then collect a subject’s EEG recordings when listening the selected IADS samples, and apply the \(AN\!N_1\) to determine the subject’s emotion vector. With the generic model and the corresponding individual differences, we construct the personalized model H by the projective transformation. In the testing phase, given a music object, the processing steps are: (1) to extract features from the music audio content, (2) to apply \(AN\!N_2\) to calculate the vector in the arousal-valence emotion space, and (3) to apply the transformation matrix H to determine the personalized emotion vector. Moreover, with respect to a moderate music object, we apply a sliding window on the music object to obtain a sequence of personalized emotion vectors, in which those predicted vectors will be fitted and organized as an emotion trail for revealing dynamics in the affective content of music object. Experimental results suggest the proposed approach is effective.

Identification of Effectors: Precipitation of Supernatant Material.

Bacterial secretion systems allow the transport of proteins, called effectors, as well as external machine components in the extracellular medium or directly into target cells. Comparison of the secretome, i.e. the proteins released in the culture medium, of wild-type and mutant cells provides information on the secretion profile. In addition, mass spectrometry analyses of the culture supernatant of bacteria grown in liquid culture under secreting conditions allows the identification of secretion system substrates. Upon identification of the substrates, the secretion profile serves as a tool to test the functionality of secretion systems. Here we present a classical method used to concentrate the culture supernatant, based on trichloroacetic acid precipitation.

Private-Sector Cyberweapons: Strategic and Other Consequences

The cyber domain exhibits a sovereignty gap: the government cannot protect the private sector against all relevant threats. The challenge of cybersecurity, therefore, is essentially one of civil defense: how to equip the private sector to protect its own computer systems in the absence of decisive government involvement. Ordinarily, civil defense in the new domain has involved passive measures, such as resilience and redundancy. Passive measures, however, will not redress the sovereignty gap unless they are complemented by a proactive approach — especially the techniques of “active defense,” which attempt to neutralize threats before they are carried out. Yet presently the authority to implement active defense belongs exclusively to the government. Top officials in the United States and other countries have called for changes in law and policy that would bolster the private sector’s ability to conduct active defense, such as by inserting web beacons or disabling external hostile machines. This paper explores the possible strategic and other consequences of arming the civilian quarters of cyberspace with active defense capabilities. It argues that while the potential defensive and other benefits of private-sector arms are significant, the risks to defenders, innocent third parties, and international conflict stability are notably greater. Cyber civil defense, in short, should remain a reactive enterprise. The paper also explores the meaning of active defense — an ambiguous and contested notion that lies at the heart of contemporary debates about cyber strategy and policy in the Journal of Cybersecurity. Some observers claim that active defense involves actions taken within the defender’s own computer terrain. Others also claim that it entails disruptive action. This paper develops a different definition: it defines active defense as any defensive action — disruptive or undisruptive or both — that a defender conducts beyond the home perimeter.

Improvement of Lubrication Performance in External Gear Machines through Micro-surface Wedged Gears

ABSTRACTThis article demonstrates how a properly designed micro-surface linear wedge added to the lateral surfaces of the gear teeth can improve the lubricating ability of external gear machines (EGMs), resulting in lower power losses and chance of wear during their operation. The approach of study is based on the use of a fluid structure interaction (FSI) model for the analysis of the lateral lubricating gaps developed in the authors' research team. Such a model is used to determine the best design of the wedged gear by considering the overall axial balance problem of pressure compensated EGMs for high-pressure applications. The article shows the numerical predictions along with the experimental verifications of the advantages offered by the proposed solution in terms of torque loss reduction for a particular reference pump.

An investigation on modeling and compensation of synthetic geometric errors on large machine tools based on moving least squares method

This article intends to provide an efficient modeling and compensation method for the synthetic geometric errors of large machine tools. Analytical and experimental examinations were carried out on a large gantry-type machine tool to study the spatial geometric error distribution within the machine workspace. The result shows that the position accuracy of the tool-tip is affected by all the translational axes synchronously, and the position error curve shape is non-linear and irregular. Moreover, the angular error combined with Abbe’s offset during the motion of a translational axis would cause Abbe’s error and generate significant influence on the spatial positioning accuracy. In order to identify the combined effect of the individual error component on the tool-tip position accuracy, a synthetic geometric error model is established for the gantry-type machine tool. Also, an automatic modeling algorithm is proposed to approximate the geometric error parameters based on moving least squares in combination with Chebyshev polynomials, and it could approximate the irregular geometric error curves with high-order continuity and consistency with a low-order basis function. Then, to implement real-time error compensation on large machine tools, an intelligent compensation system is developed based on the fast Ethernet data interaction technique and external machine origin shift, and experiment validations on the gantry-type machine tool showed that the position accuracy could be improved by 90% and the machining precision could be improved by 85% after error compensation.

Novel switched flux machine with radial and circumferential permanent magnets

Purpose– The paper purposes a novel SFPM machine topology with radial and circumferential permanent magnets (PMs). The paper aims to discuss this issue.Design/methodology/approach– In order to reduce the flux leakage in the stator-outer region and consequently achieve higher magnetic material utilization in switched flux permanent magnet (SFPM) machine, a novel topology with radial and circumferential PMs is proposed. This topology (SFRCPM) has the same structure as conventional SFPM (CSFPM) machine except of the additional set of radially magnetized PMs located around the back iron and surrounded by a laminated ring frame. Using finite element analysis (FEA) the influence of the design parameters on the performance is investigated in order to obtain an effective optimization procedure. Internal and external rotor SFRCPM machines with either NdFeB or ferrite magnets are investigated, optimized and compared with the CSFPM machine having the same size, copper loss and stator/rotor pole combination.Findings– It is concluded that comparing SFRCPM with its CSFPM machine counterpart, internal rotor SFRCPM machine can achieve high PM flux-linkage per magnet volume, however reduced slot area leads to low output torque, whereas external rotor SFRCPM machine can produce higher torque and torque per magnet volume.Originality/value– This paper proposes a novel SFPM machine topology.

Design of external rotor switched flux memory machine with hybrid magnets

Purpose– The purpose of this paper is to propose the design concepts of external rotor switched flux hybrid magnet memory machine (SFHMMM) to further increase the torque capability while keeping the merits of internal rotor SFHMMM, such as adjustable back-EMF, and good flux weakening performance, etc.Design/methodology/approach– The torque enhancing principle of external rotor SFHMMM, and the design considerations such as feasible stator and rotor pole numbers (Ns/Nr) are discussed by equations. Then, the performances such as back-EMF, dq-axis inductances, torque and flux weakening performances are calculated and compared with the aid of finite element analysis software.Findings– The external rotor SFHMMMs have obviously larger torque capabilities compared with the internal rotor ones under the same copper loss and machine size. The main reason is that the external SFHMMs could fully utilize the inner space of stator, which offers higher slot area, larger split ratio and consequently the higher average torque. For the external rotor machines with larger rotor pole numberNr, the back-EMF adjust ratio as well as the maxim torque are better. However, leakage flux and losses also increase with Nr due to limited machine size and higher operation frequency. Considering torque capability and flux weakening performance (efficiency map), the external SFHMMM withNr=2Ns+1, e.g. 6/13Ns/Nrstator/rotor pole machine, is the optimal choice.Originality/value– This paper introduces the design concept and design considerations of external SFHMMM for the first time. The proposed machine could be a competent candidate for direct-drive electric vehicle applications.

Learning to modulate the partial powers of a single sEMG power spectrum through a novel human–computer interface

New human–computer interfaces that use bioelectrical signals as input are allowing study of the flexibility of the human neuromuscular system. We have developed a myoelectric human–computer interface which enables users to navigate a cursor to targets through manipulations of partial powers within a single surface electromyography (sEMG) signal. Users obtain two-dimensional control through simultaneous adjustments of powers in two frequency bands within the sEMG spectrum, creating power profiles corresponding to cursor positions. It is unlikely that these types of bioelectrical manipulations are required during routine muscle contractions. Here, we formally establish the neuromuscular ability to voluntarily modulate single-site sEMG power profiles in a group of naïve subjects under restricted and controlled conditions using a wrist muscle. All subjects used the same pre-selected frequency bands for control and underwent the same training, allowing a description of the average learning progress throughout eight sessions. We show that subjects steadily increased target hit rates from 48% to 71% and exhibited greater control of the cursor’s trajectories following practice. Our results point towards an adaptable neuromuscular skill, which may allow humans to utilize single muscle sites as limited general-purpose signal generators. Ultimately, the goal is to translate this neuromuscular ability to practical interfaces for the disabled by using a spared muscle to control external machines.

A Wearable Channel Selection-Based Brain-Computer Interface for Motor Imagery Detection.

Motor imagery-based brain-computer interface (BCI) is a communication interface between an external machine and the brain. Many kinds of spatial filters are used in BCIs to enhance the electroencephalography (EEG) features related to motor imagery. The approach of channel selection, developed to reserve meaningful EEG channels, is also an important technique for the development of BCIs. However, current BCI systems require a conventional EEG machine and EEG electrodes with conductive gel to acquire multi-channel EEG signals and then transmit these EEG signals to the back-end computer to perform the approach of channel selection. This reduces the convenience of use in daily life and increases the limitations of BCI applications. In order to improve the above issues, a novel wearable channel selection-based brain-computer interface is proposed. Here, retractable comb-shaped active dry electrodes are designed to measure the EEG signals on a hairy site, without conductive gel. By the design of analog CAR spatial filters and the firmware of EEG acquisition module, the function of spatial filters could be performed without any calculation, and channel selection could be performed in the front-end device to improve the practicability of detecting motor imagery in the wearable EEG device directly or in commercial mobile phones or tablets, which may have relatively low system specifications. Finally, the performance of the proposed BCI is investigated, and the experimental results show that the proposed system is a good wearable BCI system prototype.

Development of a Wearable Motor-Imagery-Based Brain-Computer Interface.

A motor-imagery-based brain-computer interface (BCI) is a translator that converts the motor intention of the brain into a control command to control external machines without muscles. Numerous motor-imagery-based BCIs have been successfully proposed in previous studies. However, several electroencephalogram (EEG) channels are typically required for providing sufficient information to maintain a specific accuracy and bit rate, and the bulk volume of these EEG machines is also inconvenient. A wearable motor imagery-based BCI system was proposed and implemented in this study. A wearable mechanical design with novel active comb-shaped dry electrodes was developed to measure EEG signals without conductive gels at hair sites, which is easy and convenient for users wearing the EEG machine. In addition, a wireless EEG acquisition module was also designed to measure EEG signals, which provides a user with more freedom of motion. The proposed wearable motor-imagery-based BCI system was validated using an electrical specifications test and a hand motor imagery experiment. Experimental results showed that the proposed wearable motor-imagery-based BCI system provides favorable signal quality for measuring EEG signals and detecting motor imagery.

A Possible Shielding Blanket Module for CFETR Reactor

The basic function of shielding blanket (SB) is to provide the main thermal and nuclear shielding to the vessel and external machine components. CFETR SB modules will be operated in steady mode with continuous neutron radiation and heat source. The SB module is currently operated in pulse mode, which indicates the SB module for CFETR should be designed to fit with the new operation conditions. In this paper, the SB module structural materials are investigated, and the reduced activation ferritic/martensitic steel is selected. The cooling structure of SB module is established and a new cooling system is put forward to ensure the temperature of SB module in an allowable range. The hydraulic and the thermo-mechanical performance are analyzed by finite element method. The analysis results indicate that the new cooling structure is well in the heat removal under the steady heat of CFETR.

Systematization of accuracy indices variance when modelling the forming external cylindrical turning process

The article considers the problem of accuracy deviation systematization for external cylindrical turning, proposed a hierarchical approach to the evaluation of these deviations, an approach to the analysis of nesting accuracy metrics, as well as, the common scheme of identification of deviations of the accuracy metrics for party billets in external machining were proposed.

Thermal behavior analysis and thermal error compensation for motorized spindle of machine tools

The thermal error deformation of motorized spindle plays an important role in the precision machining, while error compensation has been proved to be a cost-effective way. Herein a symmetrical solution for the thermal error problem of spindle is proposed based on the thermal behavior analysis. Firstly, the heat generating and transfer mechanism are described considering the heat sources. Next, ANSYS is used to achieve the steady-state and the transient thermal field distribution as well as the related deformation with the given thermal load and boundary condition. Furthermore, the NEM is proposed to predict the thermal error under random rotating speed with no use of thermal sensors, followed by the determination of two important parameters. The verification experiment of the thermal error under random rotating speed is executed. The External Machine Zero Point Shift function of the CNC system is adopted to develop the real-time compensation system on the spindle of HDBS-63 machining center. The maximum axial thermal error is greatly reduced from 55 to 16 um, while the radial one similarly reduced from 15 to 6 um. Both are improved 73% and 63% respectively. The experiment results show that NEM method is simple but of good reliability and practicality.

Compensation for CNC Machine Tools Comprehensive Error Based on Interpolation Algorithm

In order to reduce the in∞uence of comprehensive error on CNC machine’s precision, the modeling method of comprehensive error was presented in this work based on linear interpolation and Newton interpolation. By using the CNC external machine zero point ofiset function, real-time error compensation was realized online. The experimental results on a vertical milling machine show that the model is convenient in calculation and performs excellent in accuracy prediction. Therefore it is suitable for the compensation for comprehensive error of CNC machine tools.