Papers by Keyword: Force Sensor

Abstract: In this study, a sensor system was designed and manufactured to measure the interface pressure between the limbs and the orthosis or between the stump and the socket prosthesis. It is also used to determine the value and location of corrective forces when using orthosis to correct deformities in the limbs or spine. The sensor system consists of a force sensor mat (43.69 x 43.69 mm), Arduino, LCD monitor, and connecting cables. When comparing the device manufactured in this study with other devices, this device is characterized as lightweight, easy to move, low cost and gives instant pressure on the LCD screen. In this study, the interventional pressure measurement system was manufactured and programmed and compared to the F-Socket measurement system. The practical part was tested on a patient suffering from med-lateral instability in the ankle joint at the right leg. The interventional pressure between the leg and orthosis was measured in two ways at the regions (posterior, lateral, medial) .the first method using the pressure measurement system manufactured in this study and the second method by using the F-Socket device. The test results showed that the values ​​of pressure readings using the manufactured system are close to the values ​​of pressure readings obtained when using the F-Socket device. This indicates that the accuracy of the readings of the manufactured system and can be used for research purposes as well as in the process of placing pads in the appropriate place within the orthosis to correct the deformity or help to provide valuable information on the manufacturing, modification and fitting of prosthetic sockets. despite its simple structure and low cost as compared with F-Socket devise.

Abstract: At present, a method for evaluating dynamic characteristics of force sensors against small and short-duration impact forces has been developed. In this method, a small mass collides with a force sensor and the impact force is measured with high accuracy as the inertial force of the mass. A pneumatic linear bearing is used in order to realize linear motion with sufficiently small friction acting on the mass, i.e., the moving part of the bearing. Using this method, the dynamic characteristics of the force sensor are evaluated in detail: small and various-duration impact forces with maximum values of approximately 0.4-6.0 N and full width at half maximum (FWHM) of approximately 0.6-2.8 ms are applied to the force sensor and the impact responses of the force sensor are evaluated.

Abstract: Bamboo shinai is a practice sword for kendo which is the Japanese traditional fencing. The effectiveness of the shock absorption of the bamboo shinai has been shown in our previous study. Although shinai is usually made of bamboo, it is also made of carbon fiber reinforced plastic (CFRP). The impact response of bamboo shinai and CFRP shinai is compared. As a result, the difference of peak value of impact force between bamboo shinai and CFRP shinai against similar initial velocity is small. Impact response measurement of each shinai has been carried out using the Levitation Mass Method (LMM) which has been proposed by us. In this method, a mass, which is levitated with a pneumatic linear bearing and hence affected by negligible friction, is made to collide with a shinai under test. Because bamboo is natual product, resource of suitable bamboos for shinai is limited. On the other hand, carbon-fiber-reinforced-plastic (CFRP) can be designed to be suitable for a shinai, which has a fixed shock absorption characteristic for an application to the structure of robot arms. Therefore, if the shock absorption characteristic of CFRP shinai is the same as that of bamboo shinai, CFRP shinai is more suitable for the structure of robot arms.

Abstract: The piezoresistivity for force sensing in wurtzite-ZnO nanowires with [0001] orientation has been simulated on the basis of the first-principles calculations of model structures. According to the difference in wall structure, our devised nanowire models can be divided into three groups by their conductivities; no band-gap conducting models, direct band-gap semiconducting models, and indirect band-gap semiconducting models. The strain responses to carrier conductivity of n-or p-doped semiconducting wurtzite-ZnO[0001] nanowire models were calculated using band carrier densities and their corresponding effective masses derived from the one-dimensional band diagram by our original procedure for a small amount of carrier occupation. The conductivities of p-type direct band-gap models change drastically due to longitudinal uniaxial strain in the simulation: the longitudinal piezoresistance coefficient is 120 × 10^–11 Pa^–1 for p-type (ZnO)₂₄ nanowire model with 1% compressive strain at room temperature.

Abstract: Forcesensor is very important in the rehabilitation robot. However, the force sensorsignals will introduce noise easily on the process of transmitting, amplifyingand sampling, which is very unfavorable for the robot motion control. Thispaper reviews the common digital filtering algorithm and analyzes theirprinciples, advantages and disadvantages, then designs an improved filteringalgorithm combines the limiting filtering algorithm withthe first-order lag filtering algorithm. At last, this paper verifies thefiltering effect by theoretical analysis, simulation and experiments.

Abstract: A force acquisition system for digital impact tester was investigated, in which structural design of bar-shaped elastic element, circuit design as well as static analysis were involved. Based on analysis of international requirements on the detection precision of digital impact tester, information concerning the precision of sensor parameters, sensors and adhesive was collected, and adhesion sites were settled through finite element analysis and optimization. Circuit design involved zero setting, temperature compensation, amplifying circuit, filter circuit and circuits to connect host computer. Loading calibration test was performed on sensors under static working condition. According to partial authoritative examination, the linearity was 0.06%, the repetitiveness was 0.01%, the retardation was 0.08%, and the sensitivity was 1.112. According to the examination conducted in some metrology institute, the total work error of impact in a digital impact tester adopting the above force acquisition system was 2% of the impact value of a standard specimen, which has already reached the precision level and met the design requirement..

Abstract: As a mechanical component, sensor can detect spatial information. Sensor technology has been widely used in national defense, aerospace, industrial inspection and automated production areas and so on. However, the sensor calibration device cannot meet the demand of the development of the sensor. In this paper, a multi-functional force loading device, which is of good technical performance, reliable operation, wide measurement range and simple measurement method, and a six-dimensional force sensor calibration method are described.

Abstract: Dielectric elastomer sensors are a new kind of capacitive sensors. They can be used to measure forces, pressures and deformations. The sensors have several advantages such as high elasticity and inexpensive fabrication compared with traditional sensors. In this paper, a new sensing device for measuring small concentrated force is proposed. The structure of the device is a cantilever beam with constant strength on which is fixed the dielectric membrane. The dielectric membrane is a capacitance sensor built with dielectric polymer coated with soft electrodes. When the cantilever beam is subjected to a concentrated force at its free end, the strain changed in the cantilever beam will induce the change in the capacitance of the membrane. According to the relation, the unknown concentrated force can be monitored by measuring the change in the capacitance. The testing results on the device show that the concentrated force at the free end of the cantilever beam is approximately proportional to the change in the capacitance. The prototype demonstrated the new device is capable of monitoring small concentrated force with prominent sensitivity.

Abstract: This paper introduces an electro-mechanical dual acting pulley continuously variable transmission (EMDAP CVT) system and presents a method of measuring belt-pulley clamping force indirectly using a DC motor current sensor. The EMDAP CVT mainly consists of two movable primary (input) and secondary (output) pulley sheaves connected by metal pushing V-belt. Two DC motor’s actuation systems adjust the CVT ratio. Additionally, the secondary actuation system controls belt-pulley clamping force by adjusting the flatness of the spring discs placed at the back of each secondary pulley sheave to keep the belt tight and prevent belt slip. Ideally, a force sensor is used to measure the belt-pulley clamping force however the use of force sensor inside transmission gearbox is not feasible due to high temperature and oily environment. A viable solution for indirectly measuring the clamping force using current sensor for DC motor is proposed. Since the DC motor actuates the movable pulleys to clamp the belt, the relationship between the DC motor current and belt-pulley clamping force can then be investigated experimentally. The results will give positive impact on precisely controlling belt-pulley clamping force of EMDAP CVT using current sensor which is relatively simpler and less expensive than force sensor.

Abstract: With the introduction of clutch-by-wire technology, electro-mechanical Automated Manual Transmission (AMT) has comes into existence. This leads the Drivetrain Research Group, Universiti Teknologi Malaysia to design and developed an indigenous drive-by-wire transmission for the future; which is the electro-mechanical dual acting pulley (EMDAP) continuously variable transmission (CVT). The group then designed and developed an indigenous drive-by-wire clutch, i.e. the electro-mechanical friction clutch (EMFC) to be integrated with the EMDAP CVT. However, to effectively electro-mechanically control the friction clutch, the relationship between motor current and clutch torque and normal force need to be fundamentally studied and established. The purpose of this paper is to set-up an experimental test rig to study electro-mechanical friction clutch actuator behavior and evaluate the correlation between the DC motor current, clutch torque and normal force of the friction clutch. Results from the correlation study will allow researchers not only to measure but also to later control the clutch clamping force using current sensor which relatively would be much simpler and less expensive than using force sensor.