Resistive Potentiometer Research Articles

A System for Collecting and Evaluating Load Information about Bioelectric Signals of the Muscular Apparatus of the Foot of a Person with Cerebral Palsy

The purpose of the research is to develop a system of biomechanical investigation of the volume of movement in the foot and ankle joint for the diagnosis of patients with cerebral palsy in assessing the quality of rehabilitation measures. The process of creating a computer diagnostic system for patients with impaired motor functions of the lower extremities, which is equipped with special bio-measuring devices provided with specialized algorithms for processing the information obtained, is investigated due to the need for scientific research aimed at developing methods and tools for a comprehensive assessment of the results of physical rehabilitation using biomedical indicators.Methods of kinematic analysis of movements in the ankle joint were used, dynamic and static analyses of the forces of the supporting reactions of the foot of the lower extremities were carried out.Results. A motion detection system based on an electronic goniometer implemented on the basis of a B10K resistive potentiometer has been developed. The determination of the absolute rotation angles of the links of the diagnostic system was carried out using the MMA7361 acceleration sensor, which contains three micromachine capacitors mounted on one silicon plate. In the course of research, changing the capacitances of micromachine capacitors makes it possible to fix the recorded value in each direction. Signals passing through low-frequency filters and temperature compensation cascades are sent to the corresponding outputs X, Y and Z. The obtained angulograms allow us to evaluate the gait of the studied patient in two classes ‒ normal and in the presence of pathology.Conclusion. A system for the formation and evaluation of bioelectric signals obtained using the muscular apparatus of the foot of patients with cerebral palsy, assembled on the platform of the Arduino UNO control board and a generalpurpose personal computer, has been developed. The developed system makes it possible to register bioelectric signals with their subsequent processing using a personal computer and making diagnostic decisions.

Experimental Investigation of Temperature Distribution in a Laminar Boundary Layer over a Heated Flat Plate with Localized Transverse Cold Air Injections

This study presents an experimental investigation focused on the interaction between a transverse injection of cold air (blowing) and the boundary layer over a heated flat plate. The flat plate was equipped with a cylindrical coil heater positioned at its center along the flow direction. The constant heat flux was maintained using a variable resistance potentiometer. The flat plate with the heater was mounted inside a subsonic wind tunnel to sustain a constant laminar air flow. The primary objective of this research was to examine the effects of cold air injections through localized holes in the flat plate near the trailing edge on the thermal boundary layer thickness δt(x,Rex,Pr). The thermal boundary layer thickness was measured using K-type thermocouples and PT-100 RTD sensors, which are made to move precise, small distances using a specially constructed traversing mechanism. Cold air was injected using purposefully fabricated metal capillary tubes force-fitted into holes through the hot flat plate. The metal tubes were thermally insulated using class-F insulation, which is used in electric motor windings. The presented work focused on a fixed free-stream velocity and a fixed cold-injection velocity less than the free-stream velocity but for two-variable heat fluxes. The results show that the thermal boundary layer thickness generally increased due to the secondary cold flow.

Novel High Accuracy Resolver Topology for Space Applications.

In recent years, the space industry has experienced a significant change mainly due to the incursion of private companies, which has shaken up the sector. This new situation allows for a reduction regarding the reliability of conventional instrumentation for space while reducing the development time and manufacturing volume. Consequently, even though it has been typical to use equipment that was previously tested in space, this could be the right moment to introduce new technologies due to the previously mentioned reasons. One of the interesting technologies with great potential is the rotary sensor in applications with motors. Historically, the resistive potentiometer has been the most used due to its simplicity and robustness; however, it has several drawbacks. Due to this, the aim of this paper is to identify an interesting rotary sensor. Hence, in this article, different sensor types are studied. Then, we review the literature regarding resolvers in order to find the best topology. We designed and compared different single speed absolute position resolvers to find the ones that offered the best results. In this process, a novel resolver topology was designed that improved on the performances of any other studied topology.

Digital Converter for a Contactless Displacement Sensor

This paper presents a novel digital converter for a contactless displacement transducer. The sensor part of the proposed transducer employs a floating (contactless) wiper that moves over a resistive element. A novel signal-conditioning circuit presented here operates on the contactless resistive potentiometer element and provides a digital output that linearly varies with the position of the wiper. The signal-conditioning circuit is developed such that the digital output is independent of the coupling capacitor that arises between the floating wiper and the resistive element, thus eliminating the effect of any jitter that may arise in the movement of the wiper. Results from a prototype circuit built and tested using a prototype sensor establish the efficacy of the proffered scheme.

The Development of a Potentiometer Electric Parameter Comprehensive Test Instrument

This paper describes a sort of integrated tester controlled by STC series microcontroller that can be used to test simplex and duplex potentiometer’s total resistance, front and rear zero resistance, dynamic noise and duplex potentiometer synchronization feature. Multi-CPU parallel working mode is adopted by the tester. This paper mainly expounds the working principle of this test instrument, its software and hardware composition and the communication protocol between each part.

1A1-S06 HDDのVCMを用いた飛翔昆虫型ロボットの羽ばたき運動制御(バイオミメティクス・バイオメカトロニクス(1))

We constructed a PID feedback control system for newly developed dragonfly-type flapping robot. Each flapping wing is driven by a scissors-swing-motor (SSM), which consists of a couple of voice-coil-motors (VCMs) used in commercial hard-disk-drive. Angle of each VCM arm is detected by a resistance potentiometer, and it is used as feedback signal for the PID control. A continuous flapping motion oscillating according to a sine function of 2〜3 Hz has been well achieved by a simple PI control. To follow up a step-function signal, full PID control is necessary to minimize the settling time. The two VCMs in a SSM are so conjugated that the motion of VCM arms are largely affected by each other. Optimum parameter set for the PID control depends on the wing shape, thickness, and the angle between two arms in the SSM.

IMS-Displacement Sensors (Inductive Magnetic Saturation)

More and more automotive applications require exact position sensing. Today resistive potentiometers are the most frequently used sensors. For reasons of reliability, there are increasing demands to replace these kinds of sensors by contactless displacement sensors, without increasing the costs.

A novel low-cost noncontact resistive potentiometric sensor for the measurement of low speeds

A novel low-cost sensor system for the measurement of low angular or linear speed is presented. The sensing element consists of a noncontact resistive potentiometer. The applied sliding electrode does not make mechanical contact with the resistive layer. The processing circuit consists of a very linear oscillator which converts the position quantity to a period-modulated signal. This signal can be directly read out by a microcontroller. A novel algorithm is presented which can eliminate or strongly reduce the influence of the many nonidealities, and which results in a short measurement time. The resolution of the low-cost angular speed sensor system is about 8/spl times/10/sup -2/ r/min in a measurement time of only 80 ms. The angular range is limited by the potentiometer geometry and the finite size of the sliding electrode, and typically amounts to about 270/spl deg/. The sensor system also indicates the moving direction.

Fabric reinforced embankment test section, plaquemine Parish, Louisiana, USA

This paper describes the results of an instrumented high strength woven geotextile fabric reinforced levee test section that was designed and constructed utilizing some of the latest procedures practiced by the US Army Corps of Engineers. The levee test section was instrumented with settlement plates, slope inclinometers, and piezometers. Resistive potentiometers and strain gages were attached to the embedded fabric. The purpose of the test section was to determine the technical feasibility, construction practicality, and the economic feasibility of geotextile reinforced levees for future projects in the Corps of Engineers New Orleans District involving very soft, highly compressible foundations. The strains and loads measured on the fabric were within the range of values estimated during design. The first six months of the test section's performance has been successful. From the test section results, it is anticipated that significant cost savings will be realized when reinforced levees are utilized.

Principles, Current Practice, and Applications of Potentiometers Based on Poggendorff's Second Method

It is shown that any bilateral voltage divider may be operated backwards as a current divider in the Ayrton shunt mode (Julie element). The use of Poggendorff's second ``compensation'' method in the construction of constant resistance potentiometers is surveyed. A design of a constant resistance potentiometer (Julie nanovolt potentiometer) using a constant current source in conjunction with a Kelvin-Varley slide operating as a current divider is described and its advantages discussed. Applications are suggested for constant current sources used with current dividers. These are (a) simplified potentiometers, (b) defection potentiometers, (c) self balancing potentiometers, (d) servo error detectors, and (e) current balances. The symmetry of Poggendroff's two methods is indicated.

A transistorized carrier frequency computing amplifier

This report describes an all transistorized carrier frequency computing amplifier with a dynamic computing accuracy of 5 parts in 10 000. The amplifier has 5 independent summing inputs and may be loaded by resistive or inductive potentiometers, resolvers and winding compensated resolvers. Special precautions have been taken to reduce gain variations due to different transistor parameters. Maximum output voltage is 10 volts rms across 2 000 ohms. Current drain is approximately 20 mA from a stabilized -70 volt source. Ambient temperature range is -25 ^oC to + 55 ^oC.

Phase-shifting bridge with a potentiometer-controlled continuous operation

Models of the above continuously controlled phase-shifting bridges with one reactance and a resistive potentiometer were used in grid control circuits of gas rectifiers, in synchronizing circuits of cathode ray oscilloscopes and in other instruments. The output voltage phase displacement is very smooth, without jumps at the extreme position of the potentiometer slide. The exceptional simplicity of the continuously controlled phaseshifting bridge with a resistive potentiometer,as compared with other known types which provide a continuous output voltage phase shift through an angle of 360° · n [2], will lead to its wide application in control circuits of electronic and gas rectifiers, as well as in experimental and laboratory practice.

Null Reading Flip-Coil Fluxmeter

Two flip coils are rotated through 180° to give a precision measurement of the ratio of separate magnetic fields. The output voltages are connected in opposition and balanced in a resistance potentiometer using a sensitive galvanometer as a null indicator. The ratio of the fields is a linear function of the potentiometer setting. In fields of several thousand gauss and using a common shaft for the coils, readings were reproducible to within 0.01%. With separate selsyn motor drives the precision was 0.02%.

The measurement of errors in radiogoniometers at high and very high frequencies

A review of existing methods of measurement of the instrumental errors in inductive radiogoniometers is followed by detailed descriptions of three methods that have been used in the high- and very-high-frequency bands (3–100 Mc/s). The first, a field-coil interconnection method which requires no apparatus other than a signal generator and detector, has a limited application, but this disadvantage is offset by its simplicity. The second method makes use of a resistance potentiometer capable of a high order of accuracy at frequencies up to 30 Mc/s. In the third method two inductive piston attenuators are used. This apparatus has a very high order of accuracy, and may be used at the highest frequencies now employed for direction-finding purposes.The importance of the measurement of errors due to the electrical asymmetry of the field coils and search coil is emphasized, and methods that have been used at high and very high frequencies are described.The accuracy and limitations of the methods are discussed and their merits compared. Details of the construction of the measuring apparatus and of its calibration are given, and typical error measurements made on various goniometers are included.

A Capacitance Bridge for Determining the Ratio and Phase Angle of Potential Transformers

A capacitance bridge for the calibration of instrument potential transformers up to 300 kv is presented in this paper. This bridge provides measurements which are correct within 0.1 per cent on ratio and 3 minutes on phase angle. There are within the bridge arrangements for testing its accuracy as determined by the stability of its component arms. It is particularly desirable to have this means of self-testing if transformers are to be tested in a laboratory which does not have extensive standardizing facilities. Further advantages beyond accuracy for standardization purposes are flexibility and ease of operation for production testing, and low cost and small volume as compared to a high-voltage resistance potentiometer.

The Measurement of High-Surge Voltages

With the application of surge tests to high voltage electrical apparatus, the question of the measurement of high-surge voltages has become a subject of prime importance. It is accordingly desired in Part I to show the practical work done in the laboratory at Sharon to calibrate the measuring devices, and in Part II to study the more interesting fundamental relationships that affect the operation and accuracy of these measuring devices. The methods of voltage measurement used are the resistance potentiometer, capacity potentiometer, and sphere gap. The potentiometers serve as dividers of the high-surge voltages for measurement at the cathode-ray oscillograph. The resistance potentiometer is a fundamental standard but requires consideration of its limitations for very rapid phenomena. In cases where these can be compensated for or are negligible, the resistance potentiometer method is very desirable. The capacity potentiometer is a secondary standard which can be calibrated. If corona and oscillations can be eliminated, it is a very desirable method of measurement, inasmuch as it is less subject to distorting the wave shape of the surge. The sphere gap is useful as a secondary standard for occasional check measurements, and it is of interest that formulas derived from smaller gaps still hold, as indicated by the check between the calculated curve for the 200-cm sphere gap and the calibration points with the resistance potentiometer.