A Pedal Dynamometer for Off-Road Bicycling

1998 ◽  
Vol 120 (1) ◽  
pp. 160-164 ◽  
Author(s):  
T. Rowe ◽  
M. L. Hull ◽  
E. L. Wang
Keyword(s):  
Wheatstone Bridge ◽  
Accuracy Evaluation ◽  
Strain Gages ◽  
Original Design ◽  
Road Cycling ◽  
Accuracy Check ◽  
Force Components ◽  
Bridge Circuits ◽  
Mean Square Errors ◽  
Ergometer Cycling

This paper describes the design and accuracy evaluation of a dynamometric pedal, which measures the two pedal force components in the plane of the bicycle. To realize a design that could be used during actual off-road cycling, a popular clipless pedal available commercially was modified so that both the form and the function of the original design were maintained. To measure the load components of interest, the pedal spindle was replaced with a spindle fixed to the pedal body and instrumented with eight strain gages connected into two Wheatstone bridge circuits. The new spindle is supported by bearings in the crank arm. Static calibration and a subsequent accuracy check revealed root mean square errors of less than 1 percent full scale (FS) when only the force components of interest were applied. Application of unmeasured load components created an error less than 2 percent FS. The natural frequency with half the weight of a 75 kgf person standing on the pedal was greater than 135 Hz. These performance capabilities make the dynamometer suitable for measuring either pedaling loads due to the rider’s muscular action or inertial loads due to surface-induced acceleration. To demonstrate this suitability, sample pedal load data are presented both for steady-state ergometer cycling and coasting over a rough surface while standing.

A Hub Dynamometer for Measurement of Wheel Forces in Off-Road Bicycling

1999 ◽  
Vol 121 (1) ◽  
pp. 132-137 ◽  
Author(s):  
D. S. De Lorenzo ◽  
M. L. Hull
Keyword(s):  
Measurement Errors ◽  
Center Of Pressure ◽  
Reaction Force ◽  
Front Wheel ◽  
Full Scale ◽  
Contact Forces ◽  
Ground Contact ◽  
Strain Gages ◽  
Accuracy Check ◽  
Force Components

A dynamometric hubset that measures the two ground contact force components acting on a bicycle wheel in the plane of the bicycle during off-road riding while either coasting or braking was designed, constructed, and evaluated. To maintain compatibility with standard mountain bike construction, the hubs use commercially available shells with modified, strain gage-equipped axles. The axle strain gages are sensitive to forces acting in the radial and tangential directions, while minimizing sensitivity to transverse forces, steering moments, and variations in the lateral location of the center of pressure. Static calibration and a subsequent accuracy check that computed differences between applied and apparent loads developed during coasting revealed root mean squared errors of 1 percent full-scale or less (full-scale load = 4500 N). The natural frequency of the rear hub with the wheel attached exceeded 350 Hz. These performance capabilities make the dynamometer useful for its intended purpose during coasting. To demonstrate this usefulness, sample ground contact forces are presented for a subject who coasted downhill over rough terrain. The dynamometric hubset can also be used to determine ground contact forces during braking providing that the brake reaction force components are known. However, compliance of the fork can lead to high cross-sensitivity and corresponding large (>5 percent FS) measurement errors at the front wheel.

A miniature transducer for recording intestinal motility in unrestrained chronic rats.

1978 ◽  
Vol 235 (5) ◽  
pp. E532 ◽  
Author(s):  
X B Pascaud ◽  
M J Genton ◽  
P Bass
Keyword(s):  
Strain Gage ◽  
Gastrointestinal Motility ◽  
Intestinal Motility ◽  
Wheatstone Bridge ◽  
Force Transducer ◽  
Intraluminal Pressure ◽  
Pressure Waves ◽  
Small Animals ◽  
Strain Gages ◽  
Commercial Strain

An extraluminal strain gage force transducer has been developed for recording gastrointestinal motility in small animals such as rats. Two commercial strain gages are bonded and wires attached to form half a Wheatstone bridge. The device is placed between silicone sheeting and prepared for implantation. As many as six implanted transducers can record simultaneously contractions and tone variations of circular or longitudinal gastrointestinal muscles. The transducers have been implanted in more than 20 rats, with some units lasting up to 4 mo. Furthermore, good relationships exist between intraluminal pressure waves registered by a small intraluminal balloon and gut contractions registered by the transducer. The transducers are a useful and accurate tool for rodent gut motility studies.

scholarly journals Determining the force of interaction in a wheel - rail system based on measuring stresses in rails neck

2017 ◽  
Vol 76 (6) ◽  
pp. 354-361 ◽  
Author(s):  
Yu. S. Romen ◽  
O. A. Suslov ◽  
A. A. Balyaeva
Keyword(s):  
Cross Sections ◽  
Wheatstone Bridge ◽  
Digital Processing ◽  
Lateral Force ◽  
Vertical Load ◽  
Strain Gages ◽  
Rail System ◽  
The Difference ◽  
Moment Of Resistance ◽  
Probabilistic Nature

When implementing new or modernized rolling the train in most cases is in the range of 0.9-0.95 and varies de-stock, one of the main problems is the provision of both traffic pending on the position in the track of a group of wheelsets. The safety, and the strength of the carriage and the ways that are de-correlation level of the frame force measured in the carriage and termined by forces in the wheel - rail system. It is almost impossible the sum of lateral forces by its average values is 0.98. A practical to directly measure the forces of interaction between the crew and method for determining the forces of interaction with respect to the track. Their determination can be carried out by measuring the stresses in the neck of a rail was proposed by Schlumpf. It involves stresses in rails, the interdependencies of which with forces are of determining the difference of the moments in the two cross sections a probabilistic nature. Correlation of the strength and stresses for of the rail neck with the angular moment of resistance to bending being equal. In this case, when the scale factors are equal to the difference of the moments, the lateral force is determined. The calculations were made by subtracting electrical signals (four strain gauges were included in the shoulders of the Wheatstone bridge), and a separate bridge was used to determine the vertical load. Errors in determining the lateral force are due to inaccurate location of the sensor sticking, the difference in the dimensions of the rail neck and the displacement of the point of application of the vertical load on the rail head. However, since the maximum forces are realized when the wheel climbs on the rail, this displacement varies insignificantly. Therefore, the results obtained can be used in conducting certification tests. The method of digital processing of data on stresses at three points of the rail neck requires for its implementation more strain gages, but the accuracy of its results is much higher, since it depends only on the errors of preliminary calibration of the cross sections. The error in calculating the forces does not exceed 4%, which shows the expediency of using the three-point method in determining the interaction forces to establish the conditions of circulation.

A New Gas Bio-Sensor in the Structure of a Micro-Machined Clamped-Clamped Inertial Beam and its Readout Circuit

2012 ◽  
Author(s):  
Bing-Ze Xue ◽  
Paul C.-P. Chao ◽  
Bor-Shyh Lin ◽  
Chun-Yin Tsai ◽  
Tsung-Lin Chen ◽  
...  
Keyword(s):  
Phase Difference ◽  
Reference Signal ◽  
Wheatstone Bridge ◽  
Phase Detector ◽  
Instrumentation Amplifier ◽  
Readout Circuit ◽  
Square Wave ◽  
On Chip ◽  
Bridge Circuits ◽  
Wave Conversion

This study presents a novel gas bio-sensor in the form of a micro-machined resonator and its readout circuit. The resonator has the structure of a clamped-clamped beam with thermal actuation and piezo-resistive sensing that supports a plate capable of being attached with test gas molecules to detect gas concentration. The purpose of this study is to design and fabricate the micro-scaled inertial beam with its readout circuit in a system-on-chip package. The circuit includes a driver, a front-end converter, a feed-trough reduction unit, a square-wave converter and a phase detector. In the process of signal reading, the sensor is first driven by a DDS module and power amplifier, and then sense the vibrations by piezo-resistivity. The piezo-resistivity is detected by a Wheatstone bridge circuits. The carried signal of modulation is processed by a Wheatstone bridge circuits. An instrumentation amplifier adjusts the gain to the appropriate amplitude. The circuit with reduction on feed-through noise increases the SNR. Square wave conversion circuit and PFD process the signal and the driver reference signal to detect phase difference. The data of phase difference is counted into a microcontroller dsPIC4011 and then the data being transmitted to the computer by RS232 to a USB adapter. Finally, the whole circuit is implemented by using TSMC 0.35 2P4M process and one-step postprocessing.

scholarly journals 3D Device for Forces in Swimming Starts and Turns

2019 ◽  
Vol 9 (17) ◽  
pp. 3559 ◽  
Author(s):  
Karla de Jesus ◽  
Luis Mourão ◽  
Hélio Roesler ◽  
Nuno Viriato ◽  
Kelly de Jesus ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Force Plate ◽  
Three Dimensional ◽  
Wheatstone Bridge ◽  
Vertical Axis ◽  
Dynamic Force ◽  
Resonance Frequencies ◽  
Bridge Circuits ◽  
External Forces ◽  
Development And Validation

Biomechanical tools capable of detecting external forces in swimming starts and turns have been developed since 1970. This study described the development and validation of a three-dimensional (six-degrees of freedom) instrumented block for swimming starts and turns. Seven force plates, a starting block, an underwater structure, one pair of handgrips and feet supports for starts were firstly designed, numerically simulated, manufactured and validated according to the Fédération Internationale de Natation rules. Static and dynamic force plate simulations revealed deformations between 290 to 376 µε and 279 to 545 µε in the anterior-posterior and vertical axis and 182 to 328.6 Hz resonance frequencies. Force plates were instrumented with 24 strain gauges each connected to full Wheatstone bridge circuits. Static and dynamic calibration revealed linearity ( R 2 between 0.97 and 0.99) and non-meaningful cross-talk between orthogonal (1%) axes. Laboratory and ecological validation revealed the similarity between force curve profiles. The need for discriminating each upper and lower limb force responses has implied a final nine-force plates solution with seven above and two underwater platforms. The instrumented block has given an unprecedented contribution to accurate external force measurements in swimming starts and turns.

A novel CMOS-MEMS integrated pressure sensing structure based on current mirror sensing technique

2015 ◽  
Vol 32 (2) ◽  
pp. 81-95 ◽  
Author(s):  
Pradeep Kumar Rathore ◽  
Brishbhan Singh Panwar ◽  
Jamil Akhtar
Keyword(s):  
Metal Oxide ◽  
Pressure Sensor ◽  
Wheatstone Bridge ◽  
Oxide Semiconductor ◽  
Current Mirror ◽  
Pressure Sensing ◽  
Content Type ◽  
Compressive Stresses ◽  
Cmos Mems ◽  
Bridge Circuits

Purpose – The present paper aims to propose a basic current mirror-sensing circuit as an alternative to the traditional Wheatstone bridge circuit for the design and development of high-sensitivity complementary metal oxide semiconductor (CMOS)–microelectromechanical systems (MEMS)-integrated pressure sensors. Design/methodology/approach – This paper investigates a novel current mirror-sensing-based CMOS–MEMS-integrated pressure-sensing structure based on the piezoresistive effect in metal oxide field effect transistor (MOSFET). A resistive loaded n-channel MOSFET-based current mirror pressure-sensing circuitry has been designed using 5-μm CMOS technology. The pressure-sensing structure consists of three identical 10-μm-long and 50-μm-wide n-channel MOSFETs connected in current mirror configuration, with its input transistor as a reference MOSFET and output transistors are the pressure-sensing MOSFETs embedded at the centre and near the fixed edge of a silicon diaphragm measuring 100 × 100 × 2.5 μm. This arrangement of MOSFETs enables the sensor to sense tensile and compressive stresses, developed in the diaphragm under externally applied pressure, with respect to the input reference transistor of the mirror circuit. An analytical model describing the complete behaviour of the integrated pressure sensor has been described. The simulation results of the pressure sensor show high pressure sensitivity and a good agreement with the theoretical model has been observed. A five mask level process flow for the fabrication of the current mirror-sensing-based pressure sensor has also been described. An n-channel MOSFET with aluminium gate was fabricated to verify the fabrication process and obtain its electrical characteristics using process and device simulation software. In addition, an aluminium gate metal-oxide semiconductor (MOS) capacitor was fabricated on a two-inch p-type silicon wafer and its CV characteristic curve was also measured experimentally. Finally, the paper presents a comparative study between the current mirror pressure-sensing circuit with the traditional Wheatstone bridge. Findings – The simulated sensitivities of the pressure-sensing MOSFETs of the current mirror-integrated pressure sensor have been found to be approximately 375 and 410 mV/MPa with respect to the reference transistor, and approximately 785 mV/MPa with respect to each other. The highest pressure sensitivities of a quarter, half and full Wheatstone bridge circuits were found to be approximately 183, 366 and 738 mV/MPa, respectively. These results clearly show that the current mirror pressure-sensing circuit is comparable and better than the traditional Wheatstone bridge circuits. Originality/value – The concept of using a basic current mirror circuit for sensing tensile and compressive stresses developed in micro-mechanical structures is new, fully compatible to standard CMOS processes and has a promising application in the development of miniaturized integrated micro-sensors and sensor arrays for automobile, medical and industrial applications.

Evaluating the accuracy of determining the points’ position by free stationing method

2021 ◽  
Vol 971 (5) ◽  
pp. 2-9
Author(s):  
M.J. Bryn ◽  
Yu.V. Lobanova ◽  
D.A. Afonin ◽  
G.G. Shevshenko
Keyword(s):  
Mean Square Error ◽  
Input Data ◽  
Accuracy Assessment ◽  
Experimental Studies ◽  
Accuracy Evaluation ◽  
Mean Square ◽  
Polar Method ◽  
The Mean ◽  
Parametric Adjustment ◽  
Mean Square Errors

The accuracy of determining the points’ position through the free stationing method is estimated. At performing alignment work, surveying facades, executive surveys, and geodetic monitoring of buildings and structures, the method of free stationing with an electronic total station installed in any suitable place and determining its position by serif, and then using the polar method, defi ning the coordinates of the determined point is considered. The accuracy assessment is identifi ed using the formulas of calculating the mean square error for the direct and reverse angular serifs, as well as for linear ones. The authors propose algorithms of accuracy evaluation for the located point positions with non-fi xed stationing method based on the parametric adjustment, and searching ones, at the same time the algorithms shall provide adjustment by considering or ignoring the errors in the input data. To determine the mean square error of the standing point’s position and the determined points according to the results of adjustment by the free stationing method, fi eld experimental studies were carried out. Numerical examples of accuracy evaluation are provided. The compliance of the adjustment results and root-mean-square errors will mean the validity of the proposed algorithms and accuracy of the performed survey.

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