Low-cost Accelerometers Research Articles

Application of Low-Cost Accelerometers for Measuring the Operational Efficiency of a Construction Equipment Fleet

AbstractMonitoring the operational efficiency of construction equipment offers great opportunities to enhance not only the productivity but also the environmental performance of construction operations. However, existing enabling technologies still suffer from a lack of economic feasibility, as well as technological compatibility with equipment fleets that are outdated or that consist of diverse manufacturers’ models. In this context, this paper examines the feasibility of measuring the operational efficiency of equipment using low-cost accelerometers. Acceleration data in three axes were collected from a real-world operation of excavators that performed various duty cycles. Multiple features were calculated from acceleration data, and several classifiers using these features were tested to classify equipment operation into engine-off, idling, and working modes. An accuracy of over 93% was obtained in the classification of excavators’ operation. This result has demonstrated that the application of low-cos...

Evaluation of impact transmissibility on individuals with shoes and barefoot during human gait

With the increasing interest in aerobic exercises in modern society, attention should be paid not only to their benefits, but also to the risks involved. During gait execution, a sudden deceleration occurs as the foot touches the ground, causing a shockwave that travels throughout the body. The present study is aimed to develop data acquisition system for acceleration, using low-cost accelerometers for the gait assessment. Data were collected from an accelerometer at three speeds with sensors attached to the head, spine, and tibia of the user to test the acquisition system and get the real data to be processed. The results obtained with gait analysis are consistent with findings of similar studies. The gait analysis system used in the present study was found to be a practical low-cost alternative for the monitoring and study of human motion.

A New Movement Recognition Technique for Flight Mode Detection

Nowadays, in the aeronautical environments, the use of mobile communication and other wireless technologies is restricted. More specifically, the Federal Communications Commission (FCC) and the Federal Aviation Administration (FAA) prohibit the use of cellular phones and other wireless devices on airborne aircraft because of potential interference with wireless networks on the ground, and with the aircraft's navigation and communication systems. Within this context, we propose in this paper a movement recognition algorithm that will switch off a module including a GSM (Global System for Mobile Communications) device or any other mobile cellular technology as soon as it senses movement and thereby will prevent any forbidden transmissions that could occur in a moving airplane. The algorithm is based solely on measurements of a low-cost accelerometer and is easy to implement with a high degree of reliability.

Single axis accelerometer fabricated using printed circuit board techniques and laser ablation

Low-cost accelerometers could be used in applications where extremely good characteristics are not a requirement. This paper presents an accelerometer fabricated using printed circuit board (PCB) processing techniques, and laser ablation. Laser is used to remove part of the PCB substrate, releasing a mass suspended by copper beams. The structure is easily bonded to another PCB, creating a variable parallel-plate capacitor with a small gap, which capacitance varies with the movement of the mass, caused by external acceleration. The fabricated accelerometer has been compared to a commercial silicon one, showing good agreement in the measurements. The measured sensitivity was 81fF/g.

VARIOMETRIC TESTS FOR ACCELEROMETER SENSORS

Abstract. We present a comprehensive review of several variometric tests recently carried out on a home-made measurement system composed of a tern of low-cost accelerometer sensors of MEMS (Micro-Electro-Mechanical Systems) type equipped with autonomous electric supply and wireless transmission. The most important parameters characterizing the systematic errors, i.e. bias, scale factor and thermal correction factor, have been evaluated by calibration tests based upon the so-called "six -positions" static test proposed by the IEEE 517 Standard. In this way the system optimal configuration has been defined in terms of data acquisition frequency and of scale factor. In addition to such tests, partly documented elsewhere, the results of some sensitivity tests on the influence of external environmental factors are also presented. With the aim of employing the proposed MEMS-based system as a device for monitoring the onset of slope landslides, some further tests have been carried out in order to measure the inclination of rigid objects which the sensors have been fixed to. The most significant results of the tests are illustrated and discussed.

Wiimote Experiments: 3-D Inclined Plane Problem for Reinforcing the Vector Concept

In an introductory physics course where students first learn about vectors, they oftentimes struggle with the concept of vector addition and decomposition. For example, the classic physics problem involving a mass on an inclined plane requires the decomposition of the force of gravity into two directions that are parallel and perpendicular to the ramp. It takes time and effort for the students to become proficient with such a vector decomposition process. Here, we present simple lab experiments to help students learn and practice the vector concepts, by working with a familiar low-cost accelerometer, the Wii Remote (“Wiimote”).

Research on Non-Gyro Projectile’s Attitude Measurement Based on Improved Unscented Kalman Filter

Considering the control requirements of guided projectile, a novel method is studied that using three low-cost MEMS accelerometers as inertial measurement unit to construct state equation and measurement equation of system, using improved unscented Kalman filter (IUKF) to estimate the state of system. For the system characteristic of linear state equation and nonlinear measurement equation, the improved UKF nonlinear filter algorithm which combines KF and UKF was proposed. At the same time, utilizing minimal skew simplex sampling to reduce the number of sigma points, computational efficiency is enhanced. The simulation experimental results show that using IUKF algorithm can obtains good precision of estimation.

An Automated Cost-effective System for Real-time Slope Mapping in Commercial Wild Blueberry Fields

The development of site-specific agriculture has increased the need for knowledge regarding within-field variability in factors such as soil/plant characteristics and topography that influence wild blueberry (Vaccinium angustifolium) production. Surface soil properties are the first type of information most frequently used by blueberry producers in developing management plans. Topographic features are not yet routinely used to guide within-field management. The majority of blueberry fields in eastern Canada have gentle to severe topography. An automated slope measurement and mapping system (SMMS) consisting of low-cost accelerometers used as tilt sensors, differential global positioning system (DGPS), and laptop and custom software was developed. The SMMS was mounted on an all-terrain vehicle for real-time slope measurement and mapping. Six commercial wild blueberry fields were surveyed in central Nova Scotia to evaluate the performance of SMMS. The automatically sensed slopes (SS) were also compared with manually measured slopes (MS) at 20 randomly selected points in each field to examine the accuracy of SMMS. The SMMS measured slope reliably in the selected fields with root mean square error ranging from 0.12 to 0.56 degrees and correlations of SS with MS of R2 = 0.95 to 0.99. The selected fields had substantial variation in slope (ranging from 0.8 to 31.0 degrees). Therefore, the use of low-cost and reliable accelerometers with a DGPS is a better option than expensive real-time kinematic DGPS for developing cost-effective SMMS to quantify and map slopes (real-time) for planning site-specific management practices in commercial fields. The SS maps or real-time SMMS could also be used to adjust vehicle speed at particularly steep slopes.

Weightlifting Performance Measurements Using Low Cost Accelerometers With Applications to Real Time Coaching and Rehabilitation

Weightlifting Performance Measurements Using Low Cost Accelerometers With Applications to Real Time Coaching and Rehabilitation

A Single-Axis Low-Cost Accelerometer Fabricated Using Printed-Circuit-Board Techniques

This letter presents a new single-axis low-cost printed-circuit-board (PCB)-based accelerometer. Motivated by the need to develop low-cost human-sensing accelerometer, a capacitive PCB-based microelectromechanical-system (MEMS) accelerometer is developed, and the experimental results of the prototype have demonstrated that the objective is feasible. The PCB-based MEMS accelerometer is fabricated with a metal film adhered to a PCB, which forms the two electrodes of the sensing capacitor of the accelerometer. This signal is compared with the output signal of a commercially available accelerometer, ADXL330, by Analog Devices. The prototypes are designed to have a dynamic range of plusmn5 g and a bandwidth from 0 to 20 Hz, which covers the range of accelerations for human limbs. The result shows that the new low-cost accelerometer can fulfill the requirement of human motion sensing.

Detecting Intra-Fraction Motion in Patients Undergoing Radiation Treatment Using a Low-Cost Wireless Accelerometer

The utility of a novel, high-precision, non-intrusive, wireless, accelerometer-based patient orientation monitoring system (APOMS) in determining orientation change in patients undergoing radiation treatment is reported here. Using this system a small wireless accelerometer sensor is placed on a patient’s skin, broadcasting its orientation to the receiving station connected to a PC in the control area. A threshold-based algorithm is developed to identify the exact amount of the patient’s head orientation change. Through real-time measurements, an audible alarm can alert the radiation therapist if the user-defined orientation threshold is violated. Our results indicate that, in spite of its low-cost and simplicity, the APOMS is highly sensitive and offers accurate measurements. Furthermore, the APOMS is patient friendly, vendor neutral, and requires minimal user training. The versatile architecture of the APOMS makes it potentially suitable for variety of applications, including study of correlation between external and internal markers during Image-Guided Radiation Therapy (IGRT), with no major changes in hardware setup or algorithm.

Highly Accurate Inclinometer Robust to Ultralow-Frequency Acceleration Disturbances and Applications to Autotracking Antenna Systems for Vessels

This paper describes a new inclinometer that compensates for ultralow-frequency acceleration disturbances. This inclinometer consists of a low-cost accelerometer, pendulum, and rotary encoder. The key feature of this inclinometer is the estimation method used to calculate the pendulum's inertial angle. We propose two algorithms to estimate the pendulum's angle. Algorithm I uses time-averaged accelerations and some assumptions. Algorithm II applies the pendulum's equation of motion. The results of simulations and experiments confirm that both algorithms can achieve highly accurate level/angle estimations under acceleration disturbance conditions. We apply this inclinometer to an autotracking antenna system for vessels. Time simulations verify its effectiveness.

Comparison Of Low Cost Objective Physical Activity Assessment Instruments Versus The Actigraph Accelerometer

The benefits of moderate-to-vigorous physical activity (MVPA) are well known, however objective measurement of MVPA still poses challenges on a large-scale level, especially in terms of cost. Validation of low-cost accelerometers for MVPA assessment is required prior to population surveillance projects. Examples of these recently available accelerometers include the New Lifestyles NL-1000 (NL; New Lifestyles Inc., Lee's Summit, Missouri, USA, $48), an accelerometer with a modifiable MVPA intensity threshold, and the Omron HJ-151 (OM; OMRON Healthcare, Inc., Bannockburn, IL, $13), a piezoelectric pedometer which outputs MVPA based on estimated walking speed (i.e., modeled from steps/min and participant height). The ActiGraph (AG; ActiGraph LLC, Pensacola, FL, $325), is an accepted research grade accelerometer with validated cut points used to determine time spent in MVPA. PURPOSE: This purpose of this study was to compare the outputs of time spent in MVPA from NL and OM with that of the AG in free-living situations. METHODS: Participants (n=26; females=17; Age=27.3 ± 7.1, range=18-44; BMI=23.8 ± 2.8) wore the three instruments concurrently during waking hours (except for water activities) for one day (11.4 ± 2.0 hours). The NL MVPA intensity range was set to the manufacturers' default setting. Time in MVPA from the NL and OM were recorded by participants at day end. AG minute-by-minute activity counts were downloaded and converted using a validated cut point (MVPA=1952 counts/min). Descriptive statistics, percent difference, repeated measures analysis of variance, and effect size (ES) were used to compare instrument outputs. Bland-Altman plots were used to assess systematic bias between the instruments. RESULTS: Detected time in MVPA for NL, OM, and AG were 44.6 ± 22.4, 38.0 ± 19.7, and 48.0 ± 20.6 min, respectively. The difference between OM vs. AG MVPA (Ä=10.0 min) was significant (p<.001, ES=0.49). All other comparisons were not significant. Bland-Altman plots displayed no evidence of systematic bias. CONCLUSIONS: In comparison to the AG, the NL detected similar time in MVPA while the OM detected significantly lower time in MVPA. These data support the NL as a low cost alternative to the more costly AG for detection of MVPA in free-living adults, especially for population monitoring.

Low-cost accelerometers for physics experiments

The implementation of a modern game-console controller as a data acquisition interface for physics experiments is discussed. The investigated controller is equipped with three perpendicular accelerometers and a built-in infrared camera to evaluate its own relative position. A pendulum experiment is realized as a demonstration of the proposed approach.

A Redundant Accelerometric Cluster for the Measurement of Translational and Angular Acceleration and Angular Velocity of the Head

This paper reports the development and the experimental verification of a new helmet based on the use of a redundant array of accelerometers (ACs) which enables the measurement of angular velocity, angular acceleration and translational (a−g) component of the head during normal activity through an unconstrained workspace. Taking into account the outcome of a numerical simulation previously conducted, a lightweight foam bicycle helmet is equipped with ten biaxial, low-cost MEMS ACs. Validation tests were carried out by means of an instrumented pendulum, which allows the evaluation of the accuracy in the measurement of angular velocity, angular acceleration and (a−g) component over a range of 300deg∕s, 1300deg∕s2, and 7m∕s2. The effects induced by the sensor redundancy in the metrological performances of the helmet were also analyzed; in fact, by adopting an optimal selection criterion, some of the cemented ACs were ignored in the data processing, so that, in addition to the 20 axis configuration, also the clusters equipped by a total number of 18, 16, 14, or 12 sensing axes were analyzed and comparatively examined. The results clearly indicate that the redundancy reduces the effect of the noise level of the single transducers to the acceleration measurements; consequently the bandwidth of the device may be increased, because higher cutoff frequency can be chosen for the low pass filtering. The redundancy is also useful to reduce the angular velocity drift that is further decreased by adopting a drift compensation method. The results of the present experiments revealed that the presented helmet can be considered a viable tool in the measurement of head angular and translational acceleration for the assessment of equilibrium control capability. In case the evaluation of the angular velocity is required, time-limited routine clinical application (few seconds) must be performed due to the presence of relevant drift.

Attitude Estimation by Multiple-Mode Kalman Filters

This letter proposes a multiple-mode Kalman filter for one-dimensional attitude estimation using low-cost accelerometer and gyroscope. The nonlinearity and time-varying parameters are partitioned into several modes; for each mode, a linear time-invariant Kalman filter is selected. Experimental results are given to verify the proposed Kalman filter

High bandwidth tilt measurement using low-cost sensors

In this paper, a state estimation technique is developed for sensing inclination angles using low-cost sensors. A low-bandwidth tilt sensor is used along with an inaccurate rate gyro and a low-cost accelerometer to obtain the measurement. The rate gyro has an inherent bias along with sensor noise. The tilt sensor uses an internal pendulum and therefore has its own slow dynamics. These sensor dynamics were identified experimentally and combined to achieve high-bandwidth measurements using an optimal linear state estimator. Potential uses of the measurement technique range from robotics, to rehabilitation, to vehicle control.

유비쿼터스 환경에서 사용 가능한 핸드 헬드형 3차원 움직임 추적장치

This paper describes a design experience of a low-cost 6 DOF spatial tracker system where relative low accuracy and relatively long ranges, wireless communication will be achieved by means of low cost accelerometers and gyros with contemporary microprocessor. However, there are two key problems; one is the bias drift problem and the other is that single or double integration of acceleration signal suffers not only from noise but also from nonlinear effects caused by gravity. To be specific, beginning and stopping of hand motions needs to be accurately detected to initiate and terminate integration process to get position and pose of the hand from accelerometer and gyro signals, since errors due to noise and/or hand-shaking motions accumulated by integration processes. Several experimental results are shown to validate our proposed algorithms.

DYNAMIC LOAD ESTIMATION IN SILAGE HARVESTING

There are many sources of disturbances for on-the-go weighing. This study was conducted to develop a new methodto remove those disturbances and to estimate more accurate dynamic masses in silage harvesting. A mathematically simpleprocedure was developed using vertical movement information from a low-cost accelerometer, in addition to conventionalinstrumentation using load cells for mass data, and was tested using a small scale model weighing bin and a commercial silagewagon. Clear similarities were found between the patterns of low-pass filtered mass and acceleration data when both wereobtained simultaneously from the same harvesting system. Multiplication factors for acceleration data were calculated sothat the differences between the mass data and the multiplied acceleration data could be minimized. Thus, subtracting themultiplied acceleration from the mass data corresponded to deleting load cell disturbances due to vertical movements. Asmall-scale model weighing system was used to apply the developed approach to known dynamic masses. Mass estimationshowed less than 20 g measurement errors for experimental loads. The same method was applied to a commercial silage wagonwith harvested silage mass data in the 0 to 7,000 kg range. The proposed method showed that remaining error magnitudeswere reduced by 39% to 56% and standard deviations were reduced by 53% to 68 % with respect to the results of low-passfiltering and moving average.

Global Positioning System (GPS): A Low-Cost Velocity Sensor for Correcting Inertial Sensor Errors on Ground Vehicles

This paper demonstrates the ability of a standard low-cost Global Positioning System (GPS) receiver to reduce errors inherent in low-cost accelerometers and rate gyroscopes used on ground vehicles. Specifically GPS velocity is used to obtain vehicle course, velocity, and road grade, as well as to correct inertial sensors errors, providing accurate longitudinal and lateral acceleration, and pitch, roll, and yaw angular velocities. Additionally, it is shown that transient changes in sideslip (or lateral velocity), roll, and pitch angles can be measured. The method utilizes GPS velocity measurements to determine the inertial sensor errors using a kinematic Kalman Filter estimator. Simple models of the inertial sensors, which take into account the sensor noise and bias drift properties, are developed and used to design the estimator. Based on the characteristics of low-cost GPS receivers and IMU sensors, this paper presents the achievable performance of the combined system using the covariance analysis from the Kalman filter. Subsequent simulations and experiments validate both the error analysis and the methodology for utilizing GPS as a velocity sensor for correcting low-cost inertial sensor errors and providing critical vehicle state measurements.