جستجوی مقالات مرتبط با کلیدواژه "دینامومتر" در نشریات گروه "مکانیزاسیون کشاورزی"

In this research, horizontal, vertical and side forces on a single bentleg plow (SBLP) and a double bentleg plow (DBLP) at four forward speeds of 1.8, 2.3, 2.9 and 3.5 kmh-1 and at the constant depth of 40 cm was evaluated. The experiment was arranged in the randomized complete block design with four replications. In each experiment, three perpendicular soil forces were measured and recorded. Results showed that increasing forward speed from 1.8 to 3.5 kmh-1 resulted in increasing horizontal, vertical and side forces by 14, 3.5 and 1% for SBLP and 13, 1.2 and 11.5% for DBLP, respectively. Other results indicated that horizontal force for DBLP was more than twice of that for SBLP. The vertical force was lower for SBLP but it was not more than half that of DBLP and the side force for DBLP was very less than that for SBLP. Generally, using the DBLP increases tine penetration and decreases side force which leads to balanced operation of the subsoiler and tractor and therefore recommended.

In this research, the effect of forward speed at four levels (1.8, 2.3, 2.9 and 3.5 km/h), tillage depth at three levels (30, 40 and 50 cm) and wing at two levels (winged and no-winged tines) were investigated on the draft requirement, soil disturbance area and specific draft of Paraplow. The results revealed that the effect of depth and wing was more than forward speed on the studied parameters, significantly. Increasing forward speed increased draft requirement and specific draft but decreased disturbance area. Increasing depth and adding wing led to increase draft requirement, disturbance area and specific draft. Transfering winged paraplow to under the hardpan decreased specific draft, significantly. The results recommended that using lower speed, minimum depth for hardpan breakage and wing will be better. A regression model included the speed, depth and wing width was developed to predict the draft requirement.

Measurement of the draft force exerted from agricultural machineries to the tractor and the calculation of the implement power requirements is important for agriculturalists in terms of machine design and tractor-machine matching . Therefore, studies about this issue have been started from the 1950’s. Zoerbet al.,(1983) claimed that the first dynamometers have been made of spring and in reality, users had difficulties reading these dynamometers gauge due to the quick variations of the gauge pointer. Therefore the second stage was the development of the hydraulic-type dynamometers in which the oil pressure inside the hydraulic cylinder-piston set installed between machine and tractor that can be readable with a bourdontube gauge was considered as its indicator. From the first years of the 1960’s development of the strain-gauge pull-type dynamometers started.
In this study, design, fabrication and evaluation of a pull-type tractor dynamometer is considered that can be used to measure and store tractor forward velocity, and horizontal component of draft force exerted from wheel-type towed implements to the tractor. Therefore, drawbar power needed to pull the machine through the soil can be calculated. This dynamometer can also be utilized to measure three-point-hitch implement’s draft force and power requirements in condition that the RNAM (1983) method was used. In addition to measure the tractor velocity with a GPS receiver instead of a fifth wheel, the other particular issue about this dynamometer is that a remote controller is used to order data acquisition commands such as starting, ending, pausing and time zeroing in the process of data gathering.
In this study an S-type strain gauge load cell (model: SS300) and a GPS receiver (model: Micro GPS antenna AGM-10 NEO-6-M-0-001 ublox AG board) were utilized to measure the draft force and forward velocity, respectively. To calibrate the load cell sensor, in an iron material selling store, the load cell was placed between an external force with a known value and roof-type load lifter by steel cables, and external loads with the value of 1-5 ton applied to the load cell in ascending and descending order. In each loading stage, the system and measuring apparatus outputs were booked. After drawing the x-y scatter chart of paired values (system output, measuring apparatus output), regression equation between these two variables were obtained that can be utilized to calibrate this part of the system. Above-mentioned method was used to calibrate the velocity measuring part of the dynamometer with a difference that real velocity was used instead of external load and velocity output was used instead of the load cell output. After performing the calibration of the system, the developed dynamometer was utilized to measure the draft force and power requirements of a three-point-hitch moldboard plow using the RNAM method. Finally, the obtained results were compared with the other researcher’s results, and the ASAE prediction of the draft force of a moldboard plow.
According to the results of this study, the estimated equation and its coefficient of determination for the calibration of the load cell sensor were , and respectively, and the estimated equation and its coefficient of determination for the calibration of the velocity were , and respectively. Moreover, according to the results of the field tests, draft force and the power requirements of a three-bottom moldboard plow in a silty clay loam soil with the forward velocity of was measured to be , and , respectively, that were in agreement with other studies. Furthermore, the draft force results of this study, and other studies were in the range of of the which is the moldboard plow draft prediction according to the ASAE standard.
This study suggests that with the aid of the RNAM method, and the developed dynamometer, the draft force and power requirements of the tillage implements can be calculated. These results can further be utilized to match the implements with the tractor or to design new tillage implements.

The presents study designed, constructed, and statically calibrated a 6DOF force torque sensor to measure forces and moments acting on a tillage implement. The instrument could measure the three orthogonal forces acting on the implement and the three moments acting around the orthogonal axes up to a maximum force of 5 kN and a maximum moment of 5 kNm. For mechanical design of the 6DOF force torque sensor, the finite element method and Solid Works software were used. The sensing element was constructed from AISI 1045 cold-drawn steel by machining. Strain distributions were analyzed to find the optimal strain node positions in the sensor to minimize cross-sensitivity between horizontal and vertical force measurement. The forces and moments acting on the sensor were measured using strain gauge bridges. A data logger (model DT800; DataTaker) was used for logging and saving data. Calibration of the measurement system was conducted by a calibration system designed for static calibration of a6DOF force torque sensor. The calibration results showed that the sensor had appropriateprecision, sensitivity, and good repeatability for measuring forces and moments. The results showed a high degree of linearity between bridge output voltage and applied force. The interaction of the applied forces and moments was not significant.

In this paper، a low-cost dynamometer for rolling، steered wheels is described. The dynamometer was constructed to determine whether such an instrumented mechanism was practical. Four S-beam load cells، an Opto-counter and a potentiometer were used to obtain all moments، and forces using dynamic and kinematic analysis. Minimal simplifying assumptions considered for the required calculations. Overturning، aligning and rolling resistance moments besides vertical force are directly measured by the load cells. The Opto-counter detects wheel angular velocity and the potentiometer was used to measure the steering angle. The results showed that the mechanism was very well calibrated with a coefficient of determination of over 0. 99 and can be used to define wheel dynamic behavior.

For measuring the draft forces exerted by implements into tractor, we use the dynamometers that are divided into pull type or three-point hitch type. For measuring the forces between the tractor and the mounted implements, three-point hitch dynamometers are used. In this research, an adjustable three-point hitch dynamometer with a draft capacity of 25 kN was designed and built which is made up from two frames that one of them placed inside the other. The force sensing elements were comprised of a loadcell that was installed between the frames. All mounted tillage implements were able to be tested by this measuring device excluding mounted implements which are powered by PTO and by using this dynamometer, the variations of implements draft force in the different tillage conditions consist of the various work depths and different forward speeds would be studied. After design and construction steps, dynamometer was calibrated, tested and evaluated. Field tests were done by using of four mounted tillage implements and obtained data were compared by obtained data from ASAE D497.5 standard formula. So with these data, the design of tines, their stems, equipment frames and the selection of the optimal size of the tillage equipments in regard of the soil type of the region and the power of the available tractors will be more scientific and reasonable