Drawbar Force Research Articles

Desempenho energético de trator agrícola articulado: Modo manual versus automático

ABSTRACT Automatic production management (APM) is a tool that assists in the operations of agricultural tractors, increasing yield and energy efficiency. The objective of the experiment was to compare the energy and operational performance of a 373-kW articulated tractor equipped with APM and manual mode of engine transmission and rotation, across different real-world speeds. The experiment was conducted in a randomized block design with five replicates, using a split-plot arrangement with two system modes (manual and automatic) in the plots and four real-world speeds (4, 6, 8, and 10 km h-1) in the subplots, totaling 40 experimental units. The evaluated variables were: wheel slippage; engine rotation; hourly and specific fuel consumptions; drawbar force, power, and yield; operating speed; and engine thermal efficiency. The variance of the data was analyzed using Tukey’s test for the first factor, and regression analysis for the second factor and interactions. The automatic mode showed lower engine rotation and wheel slippage without compromising the other variables. The use of this mode showed energy advantages at 4 and 6 km h-1 by resulting in less fuel consumption per hour. In addition, the manual mode presented higher thermal efficiency at lower speeds than the automatic mode, which showed a linear increase.

Energy performance of farm tractor with single radial versus dual diagonal wheels in harrowing operations

ABSTRACT The farm tractor wheel interacts directly with the soil, affecting its energy and operational performance. Several works study the particularities between configurations of wheelset seeking to interpret the most efficient type and arrangement of the wheelset. However, there is still a demand for studies that elucidate decision-making regarding changing the type of wheelset or improving the pre-existing arrangement. The experiment aimed to evaluate the energy performance of farm tractors equipped with Single radial and Dual diagonal wheels in rear axle in intermediate harrowing operation. The experiment was conducted in a randomized block design. Two-wheel arrangements (Single radial and Dual diagonal) were used in the blocks, and four target velocities (4, 6, 8, and 10 km h-1), with four replicates in the subblocks, totalizing 32 experimental units. Slip of wheels, engine rotation, hourly and specific fuel consumption, force, power, and efficiency in the drawbar, operational velocity, and engine thermal efficiency were monitored. The data collected were submitted to analysis of variance and, when significant, to the Tukey test and regression analysis. The Single radial tires provided an increase in velocity and drawbar force without increasing fuel consumption, consequently providing an increase in energy and operating performance in intermediate harrowing operation.

A Simplified Approach to the Evaluation of the Influences of Key Factors on Agricultural Tractor Fuel Consumption during Heavy Drawbar Tasks under Field Conditions

The optimization of energy input on agricultural farms, such as through improved fuel consumption, is currently under investigation in agricultural mechanization research with the aim of achieving economic and environmental goals. In previous research, we developed a simplified algorithm focused on defining the most efficient tractor–implement combination considering the factors that most influence this aspect. The ASABE (American Society of Agricultural and Biological Engineers) equation for calculating the drawbar pull force was adopted to fit the results to the soil conditions. Agricultural tires of different sizes were tested at different pressure settings under field conditions to assess differences in drawbar force. The resulting algorithm underwent a linear regression analysis to achieve a simplified equation for assessing the optimal wheel-slip, mass, engine power, and tire pull force properties during drawbar works that result in optimal fuel consumption with a minimal tractor efficiency impairment. Using a specific probability density function, the Monte Carlo Simulation method introduced randomness into the input and runs a sufficiently large number of trials to identify the most probable output. The result is a simplified algorithm that can be used to investigate the effects of certain parameters on fuel consumption; however, it can be adapted to evaluate the effects of different implements, tires, engine settings, or fleet management methods on fuel consumption.

Theoretical estimation of the drawbar pull for two-axle automotive vehicles

The drawbar pull, defined as the amount of force available to an automotive vehicle at the drawbar for pulling or accelerating a load, represents an important characteristic used to define its traction performances. Because the experiments necessary to determine that force are relatively difficult and expensive to realize, a theoretical assessment of that characteristic may be extremely useful to identify the traction potential of the studied vehicle. This paper presents an algorithm able to approximate the realizable drawbar force of an automotive vehicle when it moves on different types of ground. For the computation, the ground characteristics may be adopted from the literature, while the necessary input data of the vehicle is normally given by the manufacturers or can be relatively easily obtained by measurements. The algorithm can be very useful in the primary stages of vehicle design. The paper also presents some influences of the constructive data and driving conditions on the drawbar force magnitude.

Prediction of Specific Fuel Consumption of 60 HP 2WD Tractor Using Artificial Neural Networks

In this study, specific fuel consumption was determined at different axle load, tire pressure and drawbar force for a 60 HP tractor. In addition, the results were also estimated with the help of Artificial Neural Networks (ANN), which is one of the machine learning methods. The testings were carried out on the Tractor Draft Test Track. In the study; three different drive tire inner pressures (P) (160 kPa, 120 kPa and 80 kPa), four different dynamic axle loads (W) (1796 daN, 2076 daN, 2276 daN, 2476 daN) and four different traction forces (500 daN,1000 daN, 1500 daN, 2000 daN) were tested. Specific fuel consump-tion values varied between 290.7-542.1 g/kWh depending on the draft force in the testings Despite the 38% increase in the axle load, a 3.5% decrease occurred in the specific fuel consumption values. Specific fuel consumption values in-creased when increased tire inner pressure. Specific fuel consumption in-creased by 1.03% when a 100% increase in tire pressure. In ANN, the most suc-cessful model was determined by trying different training algorithms, transfer functions and the number of neurons in the hidden layer. In the most successful network model, MAE, RMSE values for the prediction of specific fuel consump-tion were found to be 0.005331, 0.007551 respectively.

Fast neural network control of a pseudo-driven wheel on deformable terrain

The performance of the wheel-driving control scheme in wheeled mobile robots is a vital aspect in vehicular robotics applications, both for fully exerting the robot tractive capabilities and to save energy. This is especially true in contexts in which the robot must travel through unknown and unpredictable deformable terrains, such as the planetary exploration context considered in this study. To compensate the disturbances resulting from terrain deformations while simultaneously leveraging the control advantages provided by the use of the recently proposed concept of pseudo-driven wheels (PDWs), an artificial-neural-network-based control method is proposed here. This study develops and presents the network algorithms necessary for achieving active following control on velocity tracking for PDWs. To handle the considered complex and highly uncertain wheel-terrain interactions, an online sequential forgetting update method for the neural network is presented, and an improved online sequential extreme learning machine (OS-ELM), combined with a proportional integral derivative (PID) controller is used, thereby leading to an efficient and highly performant hybrid OS-ELM-PID control system. A simulation showed the feasibility of the proposed control method, and subsequent real-life experimental results demonstrate the capability of the control system in maintaining the drawbar force on the PDW within the range FDP = ±2 N.

Design of a specialized tractor to replace draft animals in small farms

Abstract This paper describes the motivation, design, and testing of a specialized farm tractor designed to replace draft animals in small farms, particularly in rural India. The proposed tractor matches the low capital cost of draft animals and has their unique ability to operate between growing crops in narrow inter-row spaces while retaining the major advantages of conventional tractors, such as low maintenance cost and reduced operator physical effort. The proposed tractor was conceived based on user needs and our implementation of a detailed terramechanics model. This tractor has a higher drawbar pull per unit mass compared to conventional tractors – a high drawbar force is needed to match the peak pull of animals, and a low mass is necessary to reduce material and vehicle costs. This quality is achieved by applying nearly the full vehicle's weight on the drive wheels, placing drive wheels in line, and locating the tillage tool between both axles. A proof-of-physics prototype of the design was instrumented to measure drawbar pull and tire slip to validate the terramechanics model and quantify traction performance. It was capable of pulling with more drawbar force per unit mass than conventional tractors and its performance can be accurately predicted by the model. During field tests on a working farm, the vehicle successfully operated in the narrow spaces between growing crops that would typically not be accessible to a low-cost, conventional small tractor. Initial farmer feedback on the design confirmed its high potential for performing farming operations.

Theoretical investigation on nonlinear dynamic characteristic of spindle system

Radial gap will occur at the spindle–tool holder interface when the spindle rotates at high speed. Therefore, the radial gap will lead to the nonlinear stiffness at the spindle–tool holder connection, and it will have effects on dynamic characteristic of spindle system. In this research, classic elastic theory is adopted to evaluate the nonlinear stiffness at spindle–tool holder interface. Dynamic model of spindle system is established considering the nonlinear stiffness at spindle–tool holder interface. The fourth-order Runge–Kutta method is applied to solve dynamic response of the spindle system. On that basis, effects of drawbar force on dynamic characteristic of the system are investigated. Considering the cutting force, effects of rotational speed on dynamic response of cutter tip are also discussed. The numerical results show that the drawbar force has effects on vibration mode of cutter tip. Chaotic motion will not occur within the range concerned in engineering practice. Considering the cutting force, the motion of cutter tip turns to be chaotic. The proper rotational speed and drawbar force should be chosen to ensure a stable cutting according to the response of cutter tip.

Comparison of Energy Used and Effects on Bulk Density and Yield by Tillage Systems in a Semiarid Condition of Mexico

Energy used for tillage is an input with a high impact on the cost of crop production; it is desirable to till the soil using minimum energy. The objective of this study was to compare the specific energy expenditure, effect on soil bulk density, and forage yield of maize, by three tillage systems: Disk plow/Disk Harrow/planter (DDP), Chisel plow/Disk harrow/planter (CHDP) and No-Tillage (NT). Energy was measured for tillage operations in the summer season of 2013, 2016, and 2017. Bulk density in 2013 and 2016. Yield in 2013 and 2014. The variables of drawbar force (kN), working speed (m s−1), width (m), depth (m), fuel consumption (L ha−1), bulk density (g cm−3), and dry matter yield (Mg ha−1) were measured. Results showed that there were significant differences in the amount of energy used per ha; DDP used an average of 379.75 MJ, CHDP 135.01 MJ, and NT 26.43 MJ. The average energy applied to the soil mass for each system was 400 J kg−1 for DDP, 255.13 J kg−1 for CHDP, and for NT was 237.8 J kg−1. The overall energy efficiency was; 18.23% for DDP, 6.88% for CHDP, and 4.77% for N. The bulk density decreased significantly after three years for NT. There were no significant differences in dry matter yield. In the semiarid condition of Mexico, CHDP and NT are options for saving from 64% to 93% of energy, compared with DDP.

Contact stiffness of spindle-tool holder based on fractal theory and multi-scale contact mechanics model

Abstract The contact stiffness of the spindle/tool holder is essential for the cutting stability of the spindle system because the elastic connection of the spindle/tool holder interface determines the dynamic characteristics of the spindle system. To predict the dynamic characteristics of the spindle system at the design stage, an analytical model of the contact stiffness of the spindle/tool holder interface was proposed based on the fractal theory and the multi-scale contact mechanics model to consider the combined effect of the cutting force and drawbar force on the contact stiffness. The fractal theory was used to characterize the micro-morphology of rough surfaces and the fractal parameters were identified by the power spectrum method. For the contact of two rough curved surfaces, the surface contact coefficient was introduced into the multi-scale contact mechanics model to correct the contact stiffness, the actual contact area and the contact stress. To verify the validity of the method, the experiments were conducted and the results showed that the modeling error of the contact stiffness was reduced from 25.13% to 4.72% by the proposed method. Finally, the effect of such factors as the cutting force, the mean roughness, the material properties, the preload and the temperature variation on the contact stiffness was discussed. The contact stiffness of spindle/tool holder interface increased with the cutting force and the drawbar force and that the contact stiffness decreased with the mean roughness. Moreover, the shear contact stiffness increased with the equivalent elastic modulus, the interference fit and the temperature. The conclusion was drawn that the model can be used to predict the contact stiffness of the spindle/tool holder interface at the design stage.

DESIGNING AND MANUFACTURING LANDSIDE BY DIFFERENT LENGTH OF MOLDBOARD PLOW AND STUDYING EFFECT IN SOME NOTES OF FIELD PERFORMANCE UNDER TWO LEVELS OF MOISTURE

A field experiment conducted In the agronomic season (2012) to study the influence of landside through two levels traditional landside with moldboard plow and the plow with manufactured landside with two levels of moisture content (9.22 – 18.36)%. according to RCBD which has been used with split plot method and its influence in measuring performance (draw bar force. slippage percentage. adhesion force. vertical and horizontal deviation percentage. the coefficient of working width exploitation and performance efficiency). Results of using plow with manufactured landside led to decrease the draw bar force. slippage percentage. adhesion force soil and horizontal deviation percentage, it also led to increase the coefficient of working width exploitation and performance efficiency. While the increase of moisture content led to decrease the draw bar force, slippage percentage, and to increase the performance efficiency. The interference between the moisture content 18.36% with manufactured landside recorded a decrease in the draw bar force and high value for performance efficiency while the interference between the moisture content 18.36% for the plow with traditional landsiderecorded less slippage percentage and recording less adhesion force with moisture content 9.22% for the plow with manufactured landside

Development and Validation of a Tractor Drawbar Force Measurement and Data Acquisition System (DAQ)

Abstract. Matching agricultural tractors to implements towed by the drawbar is one of the important aspects of machinery management for ensuring optimum performance and fuel cost savings. A field deployable tractor draft force measurement and data acquisition system was developed and evaluated as part of this research project. A drawbar instrumented to measure draft force in field operating conditions was developed and statically calibrated. The drawbar was calibrated by applying loads from 4.45 to 134 kN using a hydraulic cylinder connected to a 444.8 kN load cell. Testing was conducted with the drawbar installed on a tractor on a concrete track. The Nebraska Tractor Test Laboratory (NTTL) load car was used for applying draft loads to evaluate the instrumented drawbar. The track test consisted of seven loads corresponding to maximum power in seven gears. The draft forces as measured by the drawbar were compared to the draft measurements recorded by the load car. The error between draft force measurements of the instrumented drawbar and the load car measurements ranged from 0.21 kN (0.27%) to 0.99 kN (2.88%).There were no statistically significant differences between drawbar and load car measurements confirming that the drawbar force measurement and data acquisition (DAQ) system developed as part of this research can be used for field use. Keywords: Data acquisition, Draft load, Drawbar, LabVIEW, Strain gages, Tractor.

Contact characteristic analysis of spindle–toolholder joint at high speeds based on the fractal model

Due to the influence of centrifugal force, accurate contact stiffness model of spindle–toolholder joint at high speeds is crucial in predicting the dynamic behavior and chatter vibration of spindle–toolholder system. In this paper, a macro–micro scale hybrid model is presented to obtain the contact stiffness of spindle–toolholder joint in high speeds. The hybrid model refers to the finite element model in macro-scale and three-dimensional fractal model in micro-scale. The taper contact surface of spindle–toolholder joint is assumed flat in macro-scale and the finite element method is used to obtain the pressure distribution at different speeds. In micro-scale, the topography of contact surfaces is fractal featured and determined by fractal parameters. Asperities in micro-scale are considered as elastic and plastic deformation. Then, the contact ratio, radial and torsional contact stiffness of spindle–toolholder joint can be calculated by integrating the micro asperities. Experiments with BT40 type toolholder–spindle assembly are conducted to verify the proposed model in the case of no speed. The reasonable intervals of spindle speed and drawbar force can be obtained based on the presented hybrid model, which will provide theoretical basis for the application and optimization of the spindle–toolholder system.

Development of a dynamometric vehicle to assess the drawbar performance of high-powered agricultural tractors

Agricultural tractors are machines originally designed to mechanize agricultural tasks, especially tillage and pulling. A large part of research activities have been interested in optimizing tractor efficiency, in particular in terms of emissions and energy. In this frame, the OECD Tractor Code 2 sets out a drawbar test in specific controlled conditions with the aim of evaluating the power of the tractor available at the drawbar. The principal measurement chain relies on dynamometric vehicles (DV) that are instrumented vehicles specifically engineered to develop horizontal force at the drawbar of agricultural tractors. The CREA Laboratory of Treviglio, Italy, engineered a new dynamometric vehicle to test tractors with up to 200kW at the drawbar (245kW at the engine flywheel) and a maximum of 118kN drawbar force. The chosen basis is a FIAT 6605N truck (TM 69 6×6) which has been transformed into a hydrostatic vehicle driven by a hydraulic system and an auxiliary gearbox. The maximum drawbar force was verified up to 122kN. The drawbar power verification (200kW) was successfully carried. The final verification confirmed that the project is valid for the investigation and optimization of the parameters regarding the traction efficiency of agricultural tractors.

English

Biodiesel is made from vegetable oils, animal fats or residual oil by reaction with ethanol or methanol, renewable fuel sources decrease environmental problems. The purpose of this study is to evaluate the operational performance and smoke density of an agricultural tractor running ethyl biodiesel from buriti oil (Mauritia flexuosa), diesel B S50 and diesel B S1800. Each type of diesel was mixed with biodiesel according proportions B0, B5, B15, B25, B50 and B75, in which the number indicates the percentage of biodiesel in diesel. Fuel consumption (volumetric, weight, and specific), drawbar force and power, real travel speed and smoke density were evaluated. Replacing B S1800 and B S50 (B0 diesels) with B100 reduced smoke density by 33.33% and 28.90%, respectively. The results showed an increase of 5.41% in specific fuel consumption comparing B0 and B100. Finally, biodiesel can be considered totally or as blending for fueling tractors.

Disk harrow operational performance in three engine rotation speeds

Even with the current techniques of conservation tillage, mobilization is still a widely used practice, either in initial preparation as in reform of agricultural areas. In this context the harrows are widely used, mainly because of the good working capacity and high efficiency in tillage soil. Thus, this study aimed to evaluate the operating performance of a disc harrow in clay soil using different spins. The experiment was conducted at the Experi­mental Farm Lageado, belonging to the Faculty of Agricultural Sciences - UNESP Botucatu - SP. For accomplishment of the tillage was used a disk harrow, mark Tatu Marchesan model GAICR off-set, with a cutting width of 2.57 m and consists of 20 cut disks of 0,71 m (28 inches) spaced at 0.27 m. To exert traction the disk harrow was used of tires tractor John Deere brand, model JD6600 with power 91.48 kW (121 hp) engine. The used treatments were three engine revolutions, 157 rad s -1 (1500 rpm), 189 rad s -1 (1800 rpm) and 220 rad s -1 (2100 rpm), and evaluated the working speeds achieved, effective field capacity, operational fuel consumption, working depth of the disc harrow, skating wheels of the tractor and drawbar force. The results indicated that most job rotation provided lower fuel consumption and greater field capacity. However, the increase in speed of work provided a reduction of working depth of the discs of the harrow.

Surface fractal topography-based contact stiffness determination of spindle–toolholder joint

Accurate modeling of contact stiffness is crucial in predicting the dynamic behavior and chatter vibration of spindle–toolholder system for high-speed machining centers. This paper presents a fractal theory-based contact model of spindle–toolholder joint to obtain the contact stiffness and its real contact area. Topography of the contact surfaces of spindle–toolholder joint is fractal featured and determined by fractal parameters. Asperities in micro-scale are considered as elastic or plastic deformation. Then, the contact stiffness, the real contact area, the elastic contact force, and the plastic contact force of the whole contact surface are calculated by integrating the micro asperities. The relationship of the contact stiffness and the drawbar force follows a power law, in which the power index is determined by the fractal parameters. Experiments are conducted to verify the efficiency of the proposed model. The results from the fractal contact model of spindle–toolholder joint have good agreement with those of experiments.

Resistencia traccional del subsolador en función del ancho de trabajo

The demanded drawbar pull by a subsoiler fitted with wing and chisel tines was determined when the item-item distance varies of 80 to 160 cm. The obtained equations in both kinds of tine in the two soil textures can be used to assess the delivery power of the tractor engine to select it. The field experiment was carried up in two plots, having clay soil and clay loam soil textures. According to the accomplished measures, for the subsoiler with wing tinethe best item-item distance is 120 cm with a demanded drawbar pull of 26.20 kN on the clay soil and 27.58 kN on the clay loam soil. When the subsoiler is fitted with chisel tines, the required drawbar pull does not vary with the item-item distance varying, being the drawbar force of 20.37 kN on the clay soil and increased the 7 % on the clay loam soil.

VLIV ZATÍŽENÍ HNACÍCH NÁPRAV A VÝŠKY ZÁVĚSU NA TAHOVÉ VLASTNOSTI TRAKTORU

The goal of the experimental measurement was determination of relation among weight load of the tractor together, hitch height changes and drawbar characteristic. The measurement was realized on chassis dynamometer at MUAF in Brno. The first step consisted of rated speed characteristics measurement in conformity with OECD demands. The drawbar characteristic was measured under two selected gears. Adding 980 kg to the nominal wight of the tractor brought increasing maximal drawbar power and drawbar force together with decreasing of slip. The highest differences were observed during the mesurement of fifth gear shifted. The drawbar force grew up to 18.9% as well as the maximal drawbar power (15.2%). The maximal drawbar power at ninth gear gave 62.8 kW. The hitch height was setting to 0.54 m; 0.64 m and 0.74 m. When the hitch height was set from 0.54 m to 0.74 m the drawbar force an power on front axle was lower by reason of load reduction. As can be noticed from the final drawbar characteristics, both curves are identical up to border of maximal drawbar power. Small differences in the area of the highest slips can be ascribed to the rolling resistance.

KOMBINOVANÉ ZATĚŽOVÁNÍ TRAKTOROVÉHO MOTORU

The paper deals with influence of combined load of engine on drawbar properties of a tractor. The aim was focused on determination of power consumed via PTO and the impact on drawbar pull. During the development of the tractor is assumed that certain work will transfer operations from 60 to 60% over the PTO. Combined loading of engine power significantly reduces driving force as well as drawbar pull. In general, any change in power distribution will affect power balance and overall efficiency. Nevertheless, decreasing of drawbar force enables higher efficiency due to lower resistance in transmission to PTO. Previous researches have shown that the overall loss can achieve at the most 15 %. Ordinary efficiency of pulling tractor will not cross the limit of 70 %. The contribution brings the results of experimental work where the load was changed. The combined load can be simulated with using of chassis dynamometer along with a dynamometer connected over the PTO. Basic levels of absorbed power over the PTO were set to 50, 70 and 90 kW. These points usually presents needs for main field operations. Settings of the test were carried out of constant power transferred over the PTO. Variable part of engine power is consumed to movement what means change in tractor velocity. The results of experiment have been evaluated using spreadsheet editor and statistical software and were built into plots.