Sole Sensor Research Articles

Dual-mode scramjet control using optical emission sensors.

Closed-loop fueling control of a dual-mode scramjet was successfully demonstrated using optical emission spectroscopy as the sole sensor for controller feedback. The optical emission from species of interest (O H ∗, C H ∗, C2∗) was first characterized throughout the combustor. The relative emission intensity between species pairs was studied over a range of fueling conditions and imaging locations throughout a dual-mode scramjet combustor flow path. The pair of emissive species (C2∗/O H ∗) and imaging location that were the most sensitive to changes in fueling condition were selected for use in the control system. Changes in optical transmission of the observation windows and the impact on fuel control were explored. To our knowledge, this paper is the first demonstration of fueling control of a dual-mode scramjet using only optical emission spectroscopy as feedback.

Prediction of Three-Directional Ground Reaction Forces during Walking Using a Shoe Sole Sensor System and Machine Learning.

We developed a shoe sole sensor system with four high-capacity, compact triaxial force sensors using a nitrogen added chromium strain-sensitive thin film mounted on the sole of a shoe. Walking experiments were performed, including straight walking and turning (side-step and cross-step turning), in six healthy young male participants and two healthy young female participants wearing the sole sensor system. A regression model to predict three-directional ground reaction forces (GRFs) from force sensor outputs was created using multiple linear regression and Gaussian process regression (GPR). The predicted GRF values were compared with the GRF values measured with a force plate. In the model trained on data from the straight walking and turning trials, the percent root-mean-square error (%RMSE) for predicting the GRFs in the anteroposterior and vertical directions was less than 15%, except for the GRF in the mediolateral direction. The model trained separately for straight walking, side-step turning, and cross-step turning showed a %RMSE of less than 15% in all directions in the GPR model, which is considered accurate for practical use.

Detection of The Lower Limb Asymmetries and Discomfort Considering Foot Pressure as an Attribute

A greater number of diseases and chronic conditions are making their presence since more than a decade. It has really taken its toll during the COVID-19 period. Our concern is totally the lower part of our body which includes the hip portion along with upper thigh, knees, lower limbs and ankles. Some diseases which we have surveyed has been taking place as such are Achilles’s tendonitis, arthritis in the ankle or ankles, bunions, hammertoes, plantar pressure diseases, et cetera. There are also a lot of conditions associated with lower limb muscles such as irregular muscle toning, muscle stressing, fatigue, et cetera which takes place in individuals of almost all kinds of ages. In order to nullify these conditions, we have decided to concentrate on various foot pressure points in our body. We will be analyzing the positions and intensity of these pressure points and conclude our experiment by chalking out a graphical representation of all the data accumulated with the help of certain equipment. We will be asking the subject by giving instructions to place his or her feet on the multiple sensors insole normally (with no extra pressure from the subject’s side). Each sole sensor will send analog input data as the values of the applied foot pressure. Voltage outputs are collected from each input sensor. We will then compare the different output from different sensors with predetermined standard data (collecting from those who have normal Body Mass Index range). The comparative graph of the current subject and the standard data will then be able to help us to analyze where the disease condition is taking place. Key Words: Foot pathology, foot pressure points, lower-limb asymmetry, sole sensor, body mass index range.

Comparison of methods to derive river water temperature using thermal infrared imagery: A case study of the upper Yangtze River catchment

水温是影响河流生态环境的重要因素.传统水温观测手段受限于测站的地理位置，数据分布稀疏.近20年来随着热红外卫星传感器在空间分辨率上的革新，热红外遥感影像逐步被应用于反演河流水温，但目前相关研究聚焦于利用单颗卫星数据并使用单一水温反演方法而忽略与其他卫星以及处理方法做对比.本文以长江上游流域为例，分别评估了水文反演流程中3个步骤的差异对水温精度的影响：遥感数据（MODIS和Landsat）、大气校正方法（辐射传递模型法与JM&S单通道算法）和大气校正参数（Atmcorr和GEOS-5 FP-IT）.研究结果表明：（ⅰ）MODIS数据因为空间分辨率较低并不能满足反演长江上游流域水温的需求；（ⅱ）由于长江上游流域大气水汽含量较高，JM&S单通道算法反演水温误差过大；（ⅲ）当流域拥有实测水温资料时，最佳反演流程是使用辐射传递模型法与Atmcorr大气校正参数反演Landsat水温并进一步使用逻辑回归模型校正数据，最终所得反演水温RMSE为1.0~1.1℃；（ⅳ）对于无测站流域，较适合的流程为使用辐射传递模型法和GEOS-5 FP-IT大气校正参数并设定大气校正参数阈值，最终反演水温RMSE为1.2℃.同时研究还表明大气透过率以及大气上行辐射强度是影响反演水温精度的主要因素.因此本文建议在对不同流域进行水温反演时应尽可能对上述两种参数进行敏感性分析.;Water temperature is an essential factor that affects the ecology and environment of the river. Conventional river water temperature (RWT) measuring methods are limited by the geographic location of the hydrological station; thus, RWT data is under a sparse spatial resolution. With the improvement of the spatial resolution of thermal infrared sensors mounted on the satellites within the past twenty years, thermal infrared imagery has gradually been used to retrieve RWT. Currently, most research focuses on using sole sensor and specified processing methods without comparing with other sensors and retrieval approaches. Taking the upper Yangtze River catchment as a case study, this paper evaluates the impact of the following three steps within the entire process on the accuracy of RWT:thermal infrared data (MODIS and Landsat); atmospheric correction methods (the radiation transfer model and JM&S single-channel algorithm); atmospheric correction parameters (Atmcorr and GEOS-5 FP-IT). The results indicated that (ⅰ) MODIS data cannot meet the requirements of the study area due to its low spatial resolution; (ⅱ) As the atmospheric water vapor content is relatively high in the study catchment, the JM&S single-channel algorithm performs poorly on the retrieval; (ⅲ) When there is measured RWT within the study catchment, the proper retrieval process will be using the RTM combined with Atmcorr atmospheric correction parameter and further corrected by using the logistic regression while the final RMSE is about 1.0-1.1℃; (ⅳ) For the basin without measured RWT, the more suitable way is to use the GEOS-5 FP-IT instead and set an atmospheric correction parameter threshold. Its RMSE is approximately 1.2℃. Meanwhile, the results also present that atmospheric transmittance and upward radiation are the key parameters affecting the accuracy of RWT. Therefore, we highly recommended that a similar sensitivity analysis should be applied to other catchments for further studies.

靴底センサシステムを用いた歩行中の3次元床反力推定

There is a demand for the development of a ground reaction force measurement system that is not subject to location restrictions. In the current study, we developed a sole sensor system equipped with four high-capacity compact 3-axis force sensors using a Cr-N thin film. Using the sole sensor system, time-series data of the three-directional ground reaction forces during straight walking was estimated. Two models, a multiple regression analysis model and a Gaussian process regression model, were used for the estimation. The % root mean square error (%RMSE) and R2 values in the multiple regression analysis were 14.3 % and 0.419 in average in the left-and-right directions, respectively. The %RMSE and R2 values in the anteroposterior direction were 8.0 % and 0.869 in average, respectively, and those in the vertical direction were 8.2 % and 0.801 in average, respectively. The %RMSE and R2 values in the Gaussian process regression were 13.6 % and 0.458 in average in the left-and-right directions, respectively. The %RMSE and R2 values in the anteroposterior direction were 6.5 % and 0.891 in average, respectively, and those in the vertical direction were 4.8 % and 0.910 in average, respectively. In addition, in both models, the estimation accuracy in the 0-20% stance phase, which corresponds to the heel sensor contacting period, was lower than that in other stance phases.

A Flexible Multimodal Sole Sensor for Legged Robot Sensing Complex Ground Information during Locomotion.

Recent achievements in the field of computer vision, reinforcement learning, and locomotion control have largely extended legged robots’ maneuverability in complex natural environments. However, little research focuses on sensing and analyzing the physical properties of the ground, which is crucial to robots’ locomotion during their interaction with highly irregular profiles, deformable terrains, and slippery surfaces. A biomimetic, flexible, multimodal sole sensor (FMSS) designed for legged robots to identify the ontological status and ground information, such as reaction force mapping, contact situation, terrain, and texture information, to achieve agile maneuvers was innovatively presented in this paper. The FMSS is flexible and large-loaded (20 Pa–800 kPa), designed by integrating a triboelectric sensing coat, embedded piezoelectric sensor, and piezoresistive sensor array. To evaluate the effectiveness and adaptability in different environments, the multimodal sensor was mounted on one of the quadruped robot’s feet and one of the human feet then traversed through different environments in real-world tests. The experiment’s results demonstrated that the FMSS could recognize terrain, texture, hardness, and contact conditions during locomotion effectively and retrain its sensitivity (0.66 kPa−1), robustness, and compliance. The presented work indicates the FMSS’s potential to extend the feasibility and dexterity of tactile perception for state estimation and complex scenario detection.

A Framework for a Smart Walker System with Voice-based Virtual Assistant, Actuators & Sole Sensor for Rehabilitation Monitoring

A Framework for a Smart Walker System with Voice-based Virtual Assistant, Actuators & Sole Sensor for Rehabilitation Monitoring

NEURO-FUZZY SYSTEM FOR DETECTING PD PATIENTS BASED ON EUCLID DISTANCE, FFT, AND PCA

This study proposes a method to distinguish between healthy people and Parkinson’s disease patients using sole pressure sensor data, neural network with weighted fuzzy membership (NEWFM), and preprocessing techniques. The preprocessing techniques include fast Fourier transform (FFT), Euclidean distance, and principal component analysis (PCA), to remove noise in the data for performance enhancement. To make the features usable as inputs for NEWFM, the Euclidean distances between the left and right sole pressure sensor data were used at the first step. In the second step, the frequency scales of the Euclidean distances extracted in the first step were divided into individual scales by the FFT using the Hamming method. In the final step, 1–15 dimensions were extracted as the features of NEWFM from the individual scales by the FFT extracted in the second step by the PCA. An accuracy of 75.90% was acquired from the eight dimensions as the inputs of NEWFM.

Multichannel ECG recording from waist using textile sensors

BackgroundThe development of wearable health monitoring systems is garnering tremendous interest in research, technology and commercial applications. Their ability of providing unique capabilities in continuous, real-time, and non-invasive tracking of the physiological markers of users can provide insights into the performance and health of individuals. Electrocardiogram (ECG) signals are of particular interest, as cardiovascular disease is the leading cause of death globally. Monitoring heart health and its conditions such as ventricular disturbances and arrhythmias can be achieved through evaluating various features of ECG such as R-peaks, QRS complex, T-wave, and P-wave. Despite recent advances in biosensors for wearable applications, most of the currently available solutions rely solely on a single system attached to the body, limiting the ability to obtain reliable and multi-location biosignals. However, in engineering systems, sensor fusion, which is the optimal integration and processing of data from multiple sensors, has been a common theme and should be considered for wearables. In recent years, due to an increase in the availability and variety of different types of sensors, the possibility of achieving sensor fusion in wearable systems has become more attainable. Sensor fusion in multi-sensing systems results in significant enhancements of information inferences compared to those from systems with a sole sensor. One step towards the development of sensor fusion for wearable health monitoring systems is the accessibility to multiple reliable electrophysiological signals, which can be recorded continuously.ResultsIn this paper, we develop a textile-based multichannel ECG band that has the ability to measure ECG from multiple locations on the waist. As a proof of concept, we demonstrate that ECG signals can be reliably obtained from different locations on the waist where the shape of the QRS complex is nearly comparable with recordings from the chest using traditional gel electrodes. In addition, we develop a probabilistic approach—based on prediction and update strategies—to detect R-peaks from noisy textile data in different statuses, including sitting, standing, and jogging. In this approach, an optimal search method is utilized to detect R-peaks based on the history of the intervals between previously detected R-peaks. We show that the performance of our probabilistic approach in R-peak detection is significantly better than that based on Pan–Tompkins and optimal-threshold methods.ConclusionA textile-based multichannel ECG band was developed to track the heart rate changes from multiple locations on the waist. We demonstrated that (i) the ECG signal can be detected from different locations on the waist, and (ii) the accuracy of the detected R-peaks from textile sensors was improved by using our proposed probabilistic approach. Despite the limitations of the textile sensors that might compromise the quality of ECG signals, we anticipate that the textile-based multichannel ECG band can be considered as an effective wearable system to facilitate the development of sensor fusion methodology for pervasive and non-invasive health monitoring through continuous tracking of heart rate variability (HRV) from the waist. In addition, from the commercialization point of view, we anticipate that the developed band has the potential to be integrated into garments such as underwear, bras or pants so that individuals can use it on a daily basis.

The Role of the Primary Cilium in Sensing Extracellular pH.

Biosensors on the membrane of the vascular endothelium are responsible for sensing mechanical and chemical signals in the blood. Transduction of these stimuli into intracellular signaling cascades regulate cellular processes including ion transport, gene expression, cell proliferation, and/or cell death. The primary cilium is a well-known biosensor of shear stress but its role in sensing extracellular pH change has never been examined. As a cellular extension into the immediate microenvironment, the cilium could be a prospective sensor for changes in pH and regulator of acid response in cells. We aim to test our hypothesis that the primary cilium plays the role of an acid sensor in cells using vascular endothelial and embryonic fibroblast cells as in vitro models. We measure changes in cellular pH using pH-sensitive 2′,7′-biscarboxyethy1-5,6-carboxyfluorescein acetoxy-methylester (BCECF) fluorescence and mitogen-activated protein kinase (MAPK) activity to quantify responses to both extracellular pH (pHo) and intracellular pH (pHi) changes. Our studies show that changes in pHo affect pHi in both wild-type and cilia-less Tg737 cells and that the kinetics of the pHi response are similar in both cells. Acidic pHo or pHi was observed to change the length of primary cilia in wild-type cells while the cilia in Tg737 remained absent. Vascular endothelial cells respond to acidic pH through activation of ERK1/2 and p38-mediated signaling pathways. The cilia-less Tg737 cells exhibit delayed responsiveness to pHo dependent and independent pHi acidification as depicted in the phosphorylation profile of ERK1/2 and p38. Otherwise, intracellular pH homeostatic response to acidic pHo is similar between wild-type and Tg737 cells, indicating that the primary cilia may not be the sole sensor for physiological pH changes. These endothelial cells respond to pH changes with a predominantly K+-dependent pHi recovery mechanism, regardless of ciliary presence or absence.

A Study of the Effects of Enhanced Uniformity Control of Greenhouse Environment Variables on Crop Growth

In order to ensure high crop yield and good quality in greenhouse horticulture, the major environment control variables, such as temperature, humidity, and CO2 concentration, etc., need to be controlled properly, in order to reduce harmful effects on crop growth by minimizing the fluctuation of the thermal condition. Even though a hot water-based heating system is evidently superior to a hot air-based heating system, in terms of the thermally stable condition or energy saving, a hot air-based heating system has occupied the domestic market due to its economic efficiency from an initial investment cost saving. However, the intrinsic drawbacks of a hot air-based heating system, being more frequent variation of thermal variables and an inordinate disturbance on crops due to its convective heat delivery nature, are believed to be the main reasons for the insufficient crop yield and/or the quality deterioration. In addition, the current thermal environment monitoring system in a greenhouse, in which a sole sensor node usually covers a large part of cultivating area, seems to have a profound need of improvement in order to resolve those problems, in that the assumption of thermal uniform condition, which is adequate for a sole sensor node system, cannot be ensured in some cases. In this study, the qualitative concept of the new control variable—the degree of uniformity—is suggested as an indicator to seek ways of enhancing the crop yield and its quality based on the multiple sensor nodes system with a wireless sensor network. In contrast to a conventional monitoring system, for which a newly suggested concept of qualitative variable cannot be estimated at all, the multiple sensor nodes-based thermal monitoring system can provide more accurate and precise sensing, which enables the degree of uniformity to be checked in real-time and thus more precise control becomes possible as a consequence. From the analysis of the results of the experiment and simulation, it is found that the crops in plastic vinyl houses can be exposed to a serious level of non-uniform thermal condition. For instance, the temperature difference in the longitudinal and widthwise direction is 3.0 °C and 6.5 °C, respectively for the case of 75 × 8 m dimension greenhouse during a typical winter season, and it can be hypothesized that this level of non-uniformity might cause considerable damage to crop growth. In this paper, several variants of control systems, within the framework of the multiple sensor nodes system, is proposed to provide a more thermally-stable cultivating environment and the experimental verification is carried out for different scales of test greenhouses. The results showed that a simple change of heating mode (i.e., from a hot air- to a hot water-based heating system) can bring about a significant improvement for the non-uniformity of temperature (more or less 80%), and an additional countermeasure, with local heat flux control, can lead to a supplementary cut of non-uniformity up to 90%. Among the several variants of local heat flux control systems, the hydraulic proportional mass flow control valve system was proven to represent the best performance, and it can be hypothesized that the newly suggested qualitative variable—the degree of uniformity—with the multiple sensor nodes system can be a good alternative for seeking enhanced cultivating performance, being higher crop yield and better quality along with energy cost saving.

Vision-Based Leader–Follower Formation Control of Multiagents With Visibility Constraints

In this brief, a vision-based tracking scheme is studied for the leader–follower formation control of multiagent system under visibility constraints without communication among agents. A kinect is the sole sensor installed on each agent to estimate the pose, including relative orientations and relative positions of the local leader. A dipolar vector field is established to generate and maintain a desired formation given the desired displacement on positions among agents. The visibility constraints of kinect are converted into input constrains given the pose of the local leader, and an auxiliary system is designed to analyze the effect of visibility constraints. Combining the state of the auxiliary system with the vector filed, the proposed control protocol is able to achieve the formation tracking without global or local communication among agents. Simulation studies on the robot operating system using the Gazebo simulator and experimental results on Turtlebot2 are presented to illustrate the performance of the proposed approaches.

1H1-3 Load vector under the bone as seen from the sole sensor

1H1-3 Load vector under the bone as seen from the sole sensor

Omnidirectional Visual Navigation System for TurtleBot Using Paraboloid Catadioptric Cameras.

This paper considers a method for the visual-based navigation of a TurtleBot in an indoor/outdoor environment. The sole sensor used is Intel real senses camera attached to the paraboloid reflector mirror. Navigation is achieved by imaging system constructed using Paraboloid Reflector mirror and image processing in OpenCV. A parabolic geometry is used as a mathematical tool for proposing a methodology for on board navigation by image processing. Finally, real world experimental results for both static and relatively dynamic environments are presented and proposals made for the extension of the system.

Vision-Based Heading and Lateral Deviation Estimation for Indoor Navigation of a Quadrotor

ABSTRACT In this paper, an effective vanishing point detection method based on grid-based approach for navigation of micro aerial vehicles (MAVs) in indoor corridor environment is described. The automation and navigation of MAVs in GPS-denied indoor environments is still a challenging task. To navigate in indoor corridors, on-board camera sensor is used as a sole sensor for estimating both the vehicle position and heading. Finally, the lateral deviation and heading of an MAV from the centre towards the right or left of the corridor are computed using vanishing point coordinates between two successive frames. By exploiting geometrical constraints inside buildings, long-term stable heading information is extracted. It is shown that the proposed method effectively eliminates heading drift in indoor corridor environment and is real-time capable. The measured parameters can be used to control an MAV when it deviates from the desired path of navigation.

Segmentation and tracking of nonplanar templates to improve VSLAM

In this paper, we address the problem of visual simultaneous localization and mapping (VSLAM) using a single camera as the sole sensor. A VSLAM system estimates its position and orientation (pose) by tracking distinct landmarks in the environment using its camera. Most approaches detect feature points in the environment, using an interest point operator that looks for small textured image templates. Existing algorithms typically assume that an image template is the projection of a single planar surface patch. However, if the template is actually the projection of a nonplanar surface, tracking will eventually fail. We present an algorithm that estimates the 3D structure of a nonplanar template as it is tracked through a sequence of images. Using the 3D structure, the algorithm can more accurately predict the appearance of the template, and as a result, is better able to track the template. We then evaluate the benefit of using the new feature tracking method in VSLAM, and demonstrate that the new algorithm can track points longer, and achieve better accuracy, than if the standard single-plane feature tracking method is used. The approach is especially effective in scenes where surface discontinuities are common.

Building a 3-D Line-Based Map Using Stereo SLAM

This paper presents a graph-based visual simultaneous localization and mapping (SLAM) system using straight lines as features. Compared with point features, lines provide far richer information about the structure of the environment and make it possible to infer spatial semantics from the map. Using a stereo rig as the sole sensor, our proposed system utilizes many advanced techniques, such as motion estimation, pose optimization, and bundle adjustment. We use two different representations to parameterize 3-D lines in this paper: Plucker line coordinates for efficient initialization of newly observed line features and projection of 3-D lines, and orthonormal representation for graph optimization. The proposed system is tested with indoor and outdoor sequences, and it exhibits better reconstruction performance against a point-based SLAM system in line-rich environments.

Adaptive leader‐follower formation control of non‐holonomic mobile robots using active vision

This study is concerned with the leader-follower formation control of non-holonomic mobile robots without communication. A pan-controlled camera is the sole sensor used by the follower to observe the leader. A new vision-based formation system without range states is proposed, which eliminates the need of inter-robot range estimation. An adaptive formation controller and an adaptive camera controller are designed in the presence of unknown leader's velocities and vision-related parameters. A parameter projection algorithm is integrated into the controllers to bound the control inputs. The camera controller ensures the stable observation of the leader's features. Thus the camera constantly provides visual measurements for the formation controller which guarantees the formation maintenance. Simulation and experimental results verify the effectiveness of the proposed active vision-based formation control approach.

How 'arm-twisting' by the inducer triggers activation of the MalT transcription factor, a typical signal transduction ATPase with numerous domains (STAND).

Signal transduction ATPases with numerous domains (STAND) get activated through inducer-dependent assembly into multimeric platforms. This switch relies on the conversion of their nucleotide-binding oligomerization domain (NOD) from a closed, ADP-bound form to an open, ATP-bound form. The NOD closed form is stabilized by contacts with the arm, a domain that connects the NOD to the inducer-binding domain called the sensor. How the inducer triggers NOD opening remains unclear. Here, I pinpointed the NOD-arm interface of the MalT STAND transcription factor, and I generated a MalT variant in which this interface can be covalently locked on demand, thereby trapping the NOD in the closed state. By characterizing this locked variant, I found that the inducer is recognized in two steps: it first binds to the sole sensor with low affinity, which then triggers the recruitment of the arm to form a high-affinity arm-sensor inducer-binding site. Strikingly, this high-affinity binding step was incompatible with arm-NOD contacts maintaining the NOD closed. Through this toggling between two mutually exclusive states reminiscent of a single-pole double-throw switch, the arm couples inducer binding to NOD opening, shown here to precede nucleotide exchange. This scenario likely holds for other STANDs like mammalian NLR innate immunity receptors.

3P2-C03 高背屈性とロッカーファンクションを両立させた人工筋肉駆動型背屈支援RT(リハビリテーションロボティクス・メカトロニクス)

There is symptom of foot drop that caused by peripheral neuropathy or hemiplegia. This symptom is that ankle state is plantar flexion in swing phase of walking. As a result, accidents such as overturning or stumbling occur. Ankle foot orthosis is used at present for this. However, ankle foot orthosis conventional used in the foot drop patients leads to a bad gait because insufficient dorsiflexion assistance is not made in the swing phase. In addition, orthosis in consideration for the locker function are not many. Therefore, we developed a dorsiflexion support RT to perform dorsiflexion assistance in accordance with the foot sole sensor consideration for rocker function in this study.