Application Of Inertial Sensors Research Articles

Use of an inertial sensor and a force platform to assess static balance in participants affected by multibacillary leprosy.

Leprosy is a chronic, slowly developing infectious disease that affects the peripheral nerves, specifically Schwann cells. Individuals with the multibacillary type exhibit a propensity for developing chronic pain and a decrease in sensitivity in the plantar region, which directly interferes with balance maintenance. The evaluation of static balance in this population is made through the measurement of the center of pressure (COP) oscillations. Therefore, there is a need to investigate the association between postural control and COP oscillations using a force platform and finding accelerations of the center of mass (COM) from inertial sensors for reliable and portable balance assessment in leprosy patients. To validate the application of inertial sensors for patients with leprosy by establishing a correlation with the outcomes obtained from a force platform. This is an observational study with a case-control design, in which 30 participants with leprosy and 30 healthy participants were recruited to evaluate static balance using an inertial sensor and a force platform. Participants underwent balance assessment under two conditions (Eyes Open: OE and Eyes Closed: CE), and data from the platform and sensor were processed using Matlab computational routines. The data were quantified using four parameters: Total Displacement (TD), Area, Antero-Posterior Displacement (APdisp), and Medio-Lateral Displacement (MLdisp). The evaluated parameters showed significantly different values between the groups, where the Leprosy group exhibited significantly higher values compared to the control group, both in the OE and CE conditions for all four parameters. The sensor corroborated the differences demonstrated by the platform and followed the same trend for medio-lateral displacements and accelerations. It can be observed that the evaluated parameters exhibited a varied correlation ranging from moderate to large between the platform and the sensor. Among the four variables, MLdisp had the lowest correlation. The results partially confirmed the first hypothesis of concurrent validation, showing a moderate to large correlation between the force platform and the inertial sensor. The second hypothesis of clinical validation was also partially confirmed, as not all group differences observed in the COP measurements from the force platform were reflected in the COM measurements from the inertial sensor. Specifically, the force platform indicated greater oscillations in participants with multibacillary leprosy compared to controls, a finding statistically confirmed by the sensor for all measures except MLdisp. This research confirmed the concurrent validity of the inertial sensor with the force platform and its clinical validation, demonstrating that this instrument can be applied in clinical settings due to its low cost and ease of use. The findings may contribute to public health by identifying postural control tools for patients with multibacillary leprosy.

Simplified top-down fabrication of sub-micron silicon nanowires

Abstract Silicon nanowires are among the most promising nanotechnology building blocks in innovative devices with numerous applications as nanoelectromechanical systems. Downscaling the physical size of these devices and optimization of material functionalities by engineering their structure are two promising strategies for further enhancement of their performance for integrated circuits and future-generation sensors and actuators. Integration of silicon nanowires as transduction elements for inertial sensor applications is one prominent example for an intelligent combination of such building blocks for multiple functionalities within a single sensor. Currently, the efforts in this field are marred by the lack of batch fabrication techniques compatible with semiconductor manufacturing. Development of new fabrication techniques for such one-dimensional structures will eliminate the drawbacks associated with assembly issues. The current study aims to explore the limits of batch fabrication for a single nanowire within a thick Si layer. The objective of the current work goes beyond the state of the art with significant improvements to the recent viable approach on the monolithic fabrication of nanowires, which was based on a conformal side-wall coating for the protection of the nanoscale silicon line followed by deep etch of the substrate transforming the protected layer into a silicon nanowire. The newly developed fabrication approach eliminates side wall protection and thereby reduces both process complexity and process temperature. The technique yields promising results with possible improvements for future micro and nanofabrication processes.

Gait Alteration in Individual with Limb Loss: The Role of Inertial Sensors.

Amputation has a big impact on the functioning of patients, with negative effects on locomotion and dexterity. In this context, inertial measurement units represent a useful tool in clinical practice for motion analysis, and in the development of personalized aids to improve a patient's function. To date, there is still a gap of knowledge in the scientific literature on the application of inertial sensors in amputee patients. Thus, the aim of this narrative review was to collect the current knowledge on this topic and stimulate the publication of further research. Pubmed, Embase, Scopus, and Cochrane Library publications were screened until November 2022 to identify eligible studies. Out of 444 results, we selected 26 articles focused on movement analysis, risk of falls, energy expenditure, and the development of sensor-integrated prostheses. The results showed that the use of inertial sensors has the potential to improve the quality of life of patients with prostheses, increasing patient safety through the detection of gait alteration; enhancing the socio-occupational reintegration through the development of highly technologic and personalized prosthesis; and by monitoring the patients during daily life to plan a tailored rehabilitation program.

Graphene Coated Liquid Metal Droplet‐Enabled Dual‐Axis Integrated Accelerometer

AbstractThis paper presents the design, optimization, fabrication, and characterization of a novel accelerometer consisting of a graphene‐coated liquid metal proof mass integrated with laser‐induced graphene (LIG) resistive sensing elements. The sensor utilizes the unique electromechanical properties of eutectic gallium‐indium (EGaIn) liquid metal by confining an EGaIn droplet within a graphene‐patterned 3D pyramid cavity. The pyramid base structure imposes a restoring force on the droplet enabling continuous and simultaneous sensing in two directions using a single proof mass. Coating EGaIn droplet with graphene forms an interpenetrated protective shell around the droplet, enhancing its mobility and mechanical robustness. Design optimization of the sensing microelectrodes is performed to improve the sensor performance. The accelerometer performance is evaluated and characterized, demonstrating a sensitivity of ≈9.5 kΩ g−1 (978 Ω m−1 s2) and a cross‐axis sensitivity of ≈3 % with excellent repeatability (over 120 000 cycles). The sensor is fabricated using a scalable laser writing technique and integrated with a programmable system on a chip (PSoC) to function as a stand‐alone system for real‐time wireless motion monitoring and virtual game control. The developed Graphene/Liquid metal droplet‐based sensor is promising for applications of inertial sensors, inertial switches, and soft liquid metal robots with attractive electromechanical properties.

SCS 4th Annual Conference: Strength and Conditioning for Human Performance, Porto, Portugal, 2021.

On behalf of the Strength & Conditioning Society (SCS) and the Faculty of Sport of the University of Porto, we are pleased to present the abstracts of the SCS 4th Annual Conference: Strength and Conditioning for Human Performance, which took place in, Porto, Portugal, on 12–13 November 2021. The event was a success with invited sessions from renowned international and national speakers on a myriad of topics related to strength and conditioning and its application to health and sports performance, such as agility training and testing, high-intensity interval training in chronic conditions, hamstring strain injuries in soccer, and the utilization of surface electromyography (EMG) decomposition for assessing human performance, among others. During the Conference there were also different practical workshops on (1) velocity-based training; (2) performance testing and athlete monitoring using force platforms; (3) 3D kinematics tracking and flow force assessment in aquatic sports; (4) the application of inertial sensors for physical performance testing; (5) muscle fiber recruitment, force production, and energy expenditure in progressive bicycle testing; (6) EMG decomposition, motor-units recruitment, and muscle contraction modes; and (7) recovery strategies in team-sport athletes. Researchers and academics were able to present their latest findings by submitting the abstracts that compose this Conference Report.

Recent Trends and Practices Toward Assessment and Rehabilitation of Neurodegenerative Disorders: Insights From Human Gait.

The study of human movement and biomechanics forms an integral part of various clinical assessments and provides valuable information toward diagnosing neurodegenerative disorders where the motor symptoms predominate. Conventional gait and postural balance analysis techniques like force platforms, motion cameras, etc., are complex, expensive equipment requiring specialist operators, thereby posing a significant challenge toward translation to the clinics. The current manuscript presents an overview and relevant literature summarizing the umbrella of factors associated with neurodegenerative disorder management: from the pathogenesis and motor symptoms of commonly occurring disorders to current alternate practices toward its quantification and mitigation. This article reviews recent advances in technologies and methodologies for managing important neurodegenerative gait and balance disorders, emphasizing assessment and rehabilitation/assistance. The review predominantly focuses on the application of inertial sensors toward various facets of gait analysis, including event detection, spatiotemporal gait parameter measurement, estimation of joint kinematics, and postural balance analysis. In addition, the use of other sensing principles such as foot-force interaction measurement, electromyography techniques, electrogoniometers, force-myography, ultrasonic, piezoelectric, and microphone sensors has also been explored. The review also examined the commercially available wearable gait analysis systems. Additionally, a summary of recent progress in therapeutic approaches, viz., wearables, virtual reality (VR), and phytochemical compounds, has also been presented, explicitly targeting the neuro-motor and functional impairments associated with these disorders. Efforts toward therapeutic and functional rehabilitation through VR, wearables, and different phytochemical compounds are presented using recent examples of research across the commonly occurring neurodegenerative conditions [viz., Parkinson’s disease (PD), Alzheimer’s disease (AD), multiple sclerosis, Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS)]. Studies exploring the potential role of Phyto compounds in mitigating commonly associated neurodegenerative pathologies such as mitochondrial dysfunction, α-synuclein accumulation, imbalance of free radicals, etc., are also discussed in breadth. Parameters such as joint angles, plantar pressure, and muscle force can be measured using portable and wearable sensors like accelerometers, gyroscopes, footswitches, force sensors, etc. Kinetic foot insoles and inertial measurement tools are widely explored for studying kinematic and kinetic parameters associated with gait. With advanced correlation algorithms and extensive RCTs, such measurement techniques can be an effective clinical and home-based monitoring and rehabilitation tool for neuro-impaired gait. As evident from the present literature, although the vast majority of works reported are not clinically and extensively validated to derive a firm conclusion about the effectiveness of such techniques, wearable sensors present a promising impact toward dealing with neurodegenerative motor disorders.

Feature Extraction and Data Analysis of Basketball Motion Postures: Acquisition With an Inertial Sensor

Abstract This paper mainly analyzed the application of inertial sensors in basketball posture analysis. The data of 20 basketball players in different postures were collected by Micro-electromechanical systems inertial sensors. The mean, variance, and skewness were taken as features to compare the performance of C4.5, random forest (RF), k-nearest neighbor, and support vector machine (SVM) algorithms in analyzing posture data. It was found that the classification accuracy of the k-nearest neighbor algorithm was around 90%, and the classification accuracy of C4.5, RF, and SVM algorithms was all above 90%. The classification accuracy of the RF algorithm was the highest (98.72%), which was significantly higher than C4.5 and SVM algorithms. The results verified the advantages of the RF algorithm in basketball posture analysis. The research results confirm the reliability of the inertial sensor in the field of motion posture analysis and make some contributions to its application in sport training. This paper provides support for the analysis of motion posture.

Translational Acceleration, Rotational Speed, and Joint Angle of Patients Related to Correct/Incorrect Methods of Transfer Skills by Nurses.

Currently, due to shortages in the nursing faculty and low access to actual patients, it is difficult for students to receive feedback from teachers and practice with actual patients to obtain clinic experience. Thus, both evaluation systems and simulated patients have become urgent requirements. Accordingly, this study proposes a method to evaluate the nurse’s transfer skill through observation from the patient. After verifying the proposed method, it will be integrated with a robotic patient as a future work. To verify if such an evaluation is practical, a checklist comprising 16 steps with correct and incorrect methods was proposed by the nursing teachers. Further, the evaluation parameters were determined as translational acceleration, rotational speed, and joint angle of patient. Inertial sensors and motion capture were employed to measure the translational acceleration, rotational speed, and joint angle. An experiment was conducted with two nursing teachers, who were asked to carry out both correct and incorrect methods. According to the results, three parameters reveal the difference for a patient under correct/incorrect methods and can further be used to evaluate the nurse’s skill once the thresholds are determined. In addition, the applicability of inertial sensors is confirmed for the use of robot development.

Top-down Fabrication of Silicon Nanowires Using Thermal Oxidation and Wet Etching for Inertial Sensor Applications

Top-down Fabrication of Silicon Nanowires Using Thermal Oxidation and Wet Etching for Inertial Sensor Applications

Applications of inertial sensors in medicine: towards model-based rehabilitation of stroke

Present work introduces to the concept of a quantitative assessment of stroke rehabilitation using an inverse dynamical analysis and inertial sensors for measurement of motor functions in a clinical setting. The application in medicine gives possibilities to evaluate quantitatively damaged motor functions via instrumented analysis thus proposing an additional tool for monitoring of rehabilitation process with a larger accuracy. The paper presents a simplified dynamical model of an upper extremity which allows estimating joint torques via inverse dynamics from measured arm's kinematics. The model serves as an initial step going towards patient-specific model-based rehabilitation in the future.

Lower limb spasticity assessment using an inertial sensor: a reliability study

Spasticity is a common motor impairment in patients with neurological disorders that can prevent functional recovery after rehabilitation. In the clinical setting, its assessment is carried out using standardized clinical scales. The aim of this study was to verify the applicability of inertial sensors for an objective measurement of quadriceps spasticity and evaluate its test–retest and inter-rater reliability during the implementation of the Wartenberg pendulum test. Ten healthy subjects and 11 patients in vegetative state with severe brain damage were enrolled in this study. Subjects were evaluated three times on three consecutive days. The test–retest reliability of measurement was assessed in the first two days. The third day was devoted to inter-rater reliability assessment. In addition, the lower limb muscle tone was bilaterally evaluated at the knee joint by the modified Ashworth scale. The factorial ANOVA analysis showed that the implemented method allowed us to discriminate between healthy and pathological conditions. The fairly low SEM and high ICC values obtained for the pendulum parameters indicated a good test–retest and inter-rater reliability of measurement. This study shows that an inertial sensor can be reliably used to characterize leg kinematics during the Wartenberg pendulum test and provide quantitative evaluation of quadriceps spasticity.

Feasibility of Using Virtual and Body Worn Inertial Sensors to Detect Whole-body Decelerations during Stopping

The aim of this study was to explore the use of inertial sensors for determining the rate of deceleration of an athlete during controlled breaking during over-ground running. This study will investigate the application of inertial sensors in identifying kinematic parameters to examine the effects of shock attenuation through the body. This study consisted of participants performing a number of sub-maximal runs and stopping within given distances (6m and 3m) to control the rate of deceleration. Kinematic data was recorded using a combination of motion capture and custom build inertial sensors attached to the participants’ distal fibulas and worn in a commercially available sports vest. From the data, tibia accelerations increased by 32% while peak upper torso accelerations decreased by 0.3% resulting in an overall increase in shock attenuation of 21%. This increase in attenuation was predominantly due to the ankle to knee attenuating 39% more shock, while the knee to sacrum and sacrum to upper torso both decreased by 6% and 2% respectively. As both the inertial sensor acceleration and motion capture derived acceleration displayed similar trends in shock absorption, it is difficult to detect variations in the rate of stopping using only peak impact parameters from an inertial sensor unit located on the upper torso. This is due to the varying shock attenuation capabilities of the lower joints in particular the knee which absorbed the majority of the shock under both stopping conditions.

Characterization and calibration of MEMS inertial sensors for state and parameter estimation applications

Widening applications of inertial sensors have triggered the search for cost effective sensors and those based on MEMS technology have been gaining popularity and widespread use particularly for lower cost applications. However, inertial sensors are subject to various error sources and characteristics of these should be modelled carefully. Corrective calibration is required for successful use for anything but the most trivial applications, body state estimation and navigation being important application areas. In this paper, we review the deterministic error and random noise sources for these sensors, consider a number of inertial sensor calibration tests to provide models for these errors and derive the calibration parameters for MEMS based strapdown IMUs. We carry out these tests and present the results for a low cost and popular IMU. We further provide performance results for an example application of body state and parameter estimation using the derived calibration data and discuss our results.

The development and application of inertial sensors for sports performance assessment: Successes, failures and emerging technologies

The development and application of inertial sensors for sports performance assessment: Successes, failures and emerging technologies

Characterization of Polycrystalline Silicon-Germanium Film Deposition for Modularly Integrated MEMS Applications

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The deposition of <emphasis emphasistype="bold"><emphasis>in situ</emphasis></emphasis> boron-doped polycrystalline silicon-germanium (poly-SiGe) films in a conventional low-pressure chemical-vapor deposition reactor has been characterized using the design of experiments method. The dependencies of deposition rate, resistivity, average residual stress, strain gradient, and wet etch rate in hydrogen peroxide solution are presented. Structural layer requirements for general microelectromechanical system applications can be met within the process temperature constraint imposed by complementary metal–oxide–semiconductor (CMOS) electronics. However, residual stress and strain gradient requirements for inertial sensor applications will be difficult to meet with a single homogeneous layer of poly-SiGe that is about 2 <formula formulatype="inline"><tex>$\mu{\hbox{m}}$</tex> </formula> thick. By correlating stress depth profile measurements with cross-sectional transmission electron microscopy images, we conclude that the large strain gradient is due to highly compressive stress in the lower (initially deposited) region of the film. For films deposited at very low temperature (near the range of amorphous film deposition), <emphasis emphasistype="bold"><emphasis>in situ</emphasis></emphasis> boron doping enhances film crystallinity and reduces the strain gradient.<papernumber>2006-0066</papernumber> </para>

Study of Poly-SiGe Structural Properties for Modularly Integrated MEMS

Approaches to improve the strain gradient of low-temperature- deposited LPCVD poly-SiGe for MEMS inertial sensor applications are investigated. Correlation between the strain gradient and film microstructure is found, and the effects of film deposition conditions on film microstructure are studied. Boron-doped poly-SiGe films generally have vertically oriented grains, either conical or columnar in shape. Films with small strain gradient usually have columnar grain structure with low defect density. The best strain gradient achieved is 1.1×10-6 µm-1 for a 3.5 µm thick film deposited at 410ºC, with a worst- case variation across a 150 mm-diameter wafer of 1.6×10-5 µm- 1. The uniformity of films deposited in a batch LPCVD reactor can be improved by increasing the deposited film thickness, using a proper seeding layer, and/or depositing the film in muliple layers. Post-deposition annealing and argon implantation can be used to tune the strain gradient so that lower strain gradient can be achieved with proper deposition and annealing/implantation combinations.

Extension of the midvalue selection technique for redundancy management of inertial sensors

In many redundant inertial sensor applications, the primary goal is absolute tolerance to some specified number of failures. To achieve this tolerance, a sufficient performance margin must be provided to cover the worst-case degradation that can occur. The worst-case degradation depends upon the particular algorithm used. An optimal algorithm can be defined implicitly by taking that value which minimizes an appropriately chosen worst-case performance index as the estimate. In the important case of first-failure tolerance with five skewed sensors, a simple realization has been discovered which is the direct generalization of midvalue selection to three dimensions.

Applications for Inertial Sensors in Space

Inertial sensors have application to all phases of spaceflight ranging from launch vehicles to lunar and planetary spacecraft. New classes of sensors such as the true free rotor gyro make new concepts in celestial-inertial instruments possible. Some unusual potential space applications and experiments, as exemplified by the proposal to verify the theory of General Relativity by a gyro in low earth orbit pose unusual inertial sensor requirements.