Tractive Efficiency Research Articles

Experimental comparison of locomotion system performance of ground mobile robots in agricultural drawbar works

This paper is the first comparative study described results of locomotion system performance of ground mobile robots (wheeled and tracked tractor robots) in agricultural drawbar works. In this context, motion, slip, and tractive efficiency of the robots were compared based on the Student's t-test for tire air pressure of 20.68–55.16 kPa and robot forward speed of 0.17–0.5 m/s. Results indicate that motion efficiency of the tracked robot (93.27–95.12%) was lower than that of the wheeled robot (94.52–99.31%) with normal and maximum tire air pressure. Moreover, slip efficiency of the tracked robot (89.25–91.73%) was higher than that of the wheeled robot (80.94–89.74%) in all drawbar works. Tractive efficiency of the tracked robot (83.02–87.10%) was also higher than that of the wheeled robot (80.17–84.60%) in almost all drawbar works. Thus, it can be pointed out that the tracked robot outperformed than the wheeled robot in term of traction performance. Generally, numerical and analytical descriptions are applicable for the researchers interested in improvement and optimization of locomotion system performance of ground mobile robots in agricultural drawbar works. This type of the robots is commonly employed in agricultural environments such as field, livestock, poultry house, and greenhouse.

Vertical load distribution strategy of amphibious wheel-track vehicle using neural network and particle swarm optimization

Amphibious wheel-track vehicle (AWTV) can change the vertical load of the wheels and the tracks through the active hydro-pneumatic suspension system, which shows significant advantages in terms of maneuverability and road passing ability. However, AWTV is a strong nonlinear system. The irregularity of the road, and coupling characteristics between the vertical load of the wheel-tracks and the terrain will greatly affect the tractive efficiency of the whole vehicle. Therefore, how to effectively distribute the vertical load between the wheel and the track to improve the tractive efficiency of the whole vehicle is still a huge challenge. To address the above problems, based on the neural network (NN) and particle swarm optimization (PSO) algorithm, vertical load distribution strategy of the AWTV is proposed to improve its traction efficiency under different driving road in this paper. Firstly, the coupling dynamics model of AWTV with road and hydraulic system dynamics model of active suspension is established; Secondly, the wheel-track terrain model is built in EDEM-Recurdyn to collect data of vertical load and traction efficiency under the different soils and speeds, and the coupling function is obtained through NN; Then, the optimal vertical load of each axle is optimized through PSO; Finally, the feasibility and effectiveness of the strategy are verified by the simulation analysis under different road conditions and distribution strategies. The simulation and test results demonstrate that the proposed vertical load distribution strategy based on NN-PSO can effectively improve the traction performance of the AWTV in complex terrain environment, and have relatively superior control characteristics.

Development Status and Research Progress of a Tractor Electro-Hydraulic Hitch System

A tractor electro-hydraulic hitch system is considered one of the most important systems that play a strategic role in the power transmission and operation depth control of a tractor’s field operation. Its performance directly affects the operation quality of the whole work unit of the tractor. Furthermore, a tractor electro-hydraulic hitch system has gained the interest of many in the agricultural machinery sector because of its stable performance, high production efficiency, good operation quality and its low energy consumption. To fully benefit from the potential of the tractor electro-hydraulic hitch system, it is significant to understand and address the problems and challenges associated with it. This study, therefore, aims to contribute to the development of the tractor electro-hydraulic hitch system by investigating the research methods, technical characteristics and emerging trends in three key aspects that include the tillage depth adjustment method, the tillage depth control algorithm and the core components of the electro-hydraulic hitch system. The characteristics and applicable conditions of the different tillage depth adjustment methods of the electro-hydraulic hitch system were summarized. The realization methods and the control characteristics of the different algorithms were elaborated and discussed for both the PID control algorithm and the intelligent control algorithm. The working characteristics of the core components of the electro-hydraulic hitch system were analyzed based on the hydraulic control valves and sensing elements. The results have shown that the multi-parameter tillage depth adjustment method met the operation quality standard while taking the engine load stability and traction efficiency into account, and it has a greater research significance and value. The working quality can be improved effectively by introducing the intelligent algorithm. In addition, the study of smart valves with built-in sensing elements and how to improve the anti-interference ability of sensing elements, are the aspects that requires further consideration. Aiming to improve the working quality and reduce energy consumption, further research into the tractor electro-hydraulic hitch system is necessary. The results of this comprehensive review provide a reference for the intelligent operation of tractors under the precision agriculture.

ВЫБОР ДИАПАЗОНА ПЕРЕДАТОЧНЫХ ОТНОШЕНИЙ МЕХАНИЧЕСКОЙ ЧАСТИ ЭЛЕКТРОМЕХАНИЧЕСКОЙ ТРАНСМИССИИ ТРАКТОРА

A method has been developed for selecting the gear ratio of the mechanical part of the power train (MPPT) to work on agricultural operations of a tractor of the 5th drawbar class equipped with an electromechanical power train with a traction induction electric motor (TIM). It is assumed that there are two gears: the high one (n-th) for operation in transport mode and the low one (n–1st) for operation in operational and technological modes. The gear ratio MPPT uМЧТ,n, corresponding to the nth gear, is determined from the condition of ensuring the required maximum velocity of the tractor. The gear ratio of the MPPT uМЧТ(n–1), corresponding to the n–1st gear, must be in the range from the uМЧТ(n–1),р, at which the minimum plowing velocity will be provided at the nominal value of the voltage frequency supplied to the TIM, to the uМЧТ(n–1),max, determined by from the condition of providing the maximum possible velocity range of the tractor with only the n-th gear without overlapping its n–1st gear. A formula is also proposed for determining the value of the uМЧТ(n–1),v, at which the tractor can operate with the maximum velocity permissible for a given agricultural operation. If uМЧТ(n–1),v < uМЧТ(n–1) < uМЧТ(n–1),р, then the entire velocity range for a given agricultural operation will be provided when working in the n–1st gear. In order to determine the uМЧТ(n–1) with the best traction efficiency, it is proposed to carry out tractor traction calculation for the values of uМЧТ(n–1) taken in the range from uМЧТ(n–1),р to uМЧТ(n–1),max with a certain step. After that, for the selected value uМЧТ(n–1), it is necessary to calculate the TIM losses during tractor operation in the entire velocity range provided by the n–1st gear. If the thermal mode of the TIM is not performed when the tractor is moving at low velocities in the n–1st gear, then it is necessary either to take a larger value of the uМЧТ(n–1) at which it is performed, or in case of a small excess of the permissible power losses of the TIM, do not increase the uМЧТ(n–1), but take this into account when designing the TIM cooling system.

An independent steering driving system to realize headland turning of unmanned tractors

Headland turning is one of the factors that affect the efficiency of automatic tractors. The tractor turns in headland following a curved trajectory based on the minimum turning radius and drives into the next row, in most cases. However, the efficiency of the tractor with this turning method is limited by the steering angle range of the front wheels. In this paper, an auxiliary wheel is designed to achieve efficient headland turning by equipping a 360° steering auxiliary wheel at the front of the tractor, which includes auxiliary wheel structure, hydraulic drive system and electro-hydraulic servo controller. The designed electro-hydraulic system can realize automatic steering, lifting and driving of the auxiliary wheel. Finally, field experiments are conducted to verify the superiority of the proposed auxiliary wheel turning method compared with the existing turning methods. Experimental results show that the auxiliary wheel turning method improved the efficiency of the automatic tractor in headland by 50%, 80% and 50% respectively in terms of time efficiency, travel distance and appropriation of space compared with the conventional turning method.

Tire mobility numbers and vehicles performance evaluation based on empirical approaches

The wheel mobility number is a dimension less parameter that has a great and effective influence on prediction the off-road wheeled vehicle’s performance. The wheel mobility number is affected by soil strength, vehicle’s weight, and tires geometry. Different types of published wheel mobility numbers were collected and theoretically investigated to compare their vehicle performance. The major goal of this paper is to investigate the impact of tires parameters on vehicle mobility. For this, the tire geometry was measured using experimental testing at various tires inflation pressures. A theoretical comparison is carried out to the investigate the effect of soil cone index, tire geometry and vehicle weight on mobility numbers. The theoretical results are arranged in three worked zones and the vehicle performance in terms of net traction and tractive efficiency using empirical approaches were predicted. A comparison between predicted results and published results gives a good correlation.

Traction Calculation for Modular Energotechnological Unit Given Kinematic Mismatch of Driving Axles

The power of the engine of energy-saturated tractors often proves not to be fully used. One of the solutions to this problem might be the use of the unit technological part as an active coupling weight. To implement it, an energotechnological modular unit was created.Research purpose The purpose of the study is to determine the traction efficiency of a block-modular energotechnological unit given a kinematic discrepancy between the tractor wheels.Materials and methods The system of equilibrium equations for the transport-technological module being free-attached to the energy module is presented as the sum of forces projections on the axis. The tangent thrust force and the rolling resistance force of each axle of the energy vehicle were expressed through the corresponding normal soil reactions. When calculating multiaxle running systems, it was taken into account that the rolling resistance coefficient depends on the number of wheel passes along one trace and the degree of soil deformation by previous passes. Normal reactions of the soil to the energy module supports have been determined by considering the modular energotechnological unit as a whole, equating to zero the sum of the forces projection on the OZ axis and the sum of the moments at the point of contact between the energy module’s front wheels and the soil.Results and discussion The influence of the kinematic mismatch between the third axle and the second one on the undercarriage efficiency was investigated. Analyzing the dependence of the running system efficiency on the kinematic mismatch of the first and third axles at the traction of 30 kilonewtons, the extremes of all the dependencies at the kinematic mismatch between the third bridge and the second one different unit were detected.Conclusions It has been revealed that the change in the efficiency of the chassis system of the modular energotechnological unit depends on the kinematic mismatch between the third axle and the second one at a predetermined kinematic mismatch between the first axle and the second axle, which is a structural feature for 4K4 wheeled tractors. The excess in the values of running system efficiency equals 1.04-1.06 if the constructive kinematic mismatch between the third bridge and the second one is within 1.06-1.08.

SIMULATION MODELING OF TRACTION AND DYNAMIC INDICATORS OF TRACTORS ON THE BASIS OF POWERMIX FIELD CYCLES TEST

The paper presents a mathematical model for determining the traction and dynamic performance of tractors using PowerMix field test cycles. The mathematical model was successfully tested, during which a set of traction-dynamic parameters of a wheeled tractor with the maximum discrepancy on individual indicators relative to experimental data, which is -8.4… + 7.9%. A plan of a simulation experiment is proposed, which takes into account the distribution of the annual volume of spring and summer-autumn tractor work by typical agricultural operations, and includes loading traction cycles with power take-off through PTO and hydraulic system of the tractor. To assess the efficiency of tractors based on a set of traction-dynamic indicators obtained from field PowerMix test cycles, developed a method of bringing the simulation results to the performance of the base tractor with a capacity of 100 kW, which corresponds to the basic cycles PowerMix. The technique makes it possible to compare tractors of arbitrary design solutions and power. As an example, the results of modeling the traction and dynamic performance of the New Holland T6.180 tractor on PowerMix field test cycles determined the average values of productivity and per hectare of fuel consumption plowed by the base tractor, which are 1,239 ha / h and 14.58 kg / ha, respectively

Wheel Slip Control Applied to an Electric Tractor for Improving Tractive Efficiency and Reducing Energy Consumption.

This work presents an automatic slip control solution applied to a two-wheel-drive (2WD) electric tractor. Considering that the slip can be maintained within a specific range that depends on the type of soil, it is possible to increase the tractive efficiency of the electric vehicle (EV). The control system can be easily designed considering only the longitudinal dynamics of the tractor while using simple proportional-integral (PI) controllers to drive the inverters associated with the rear wheels. The introduced solution is tested on an experimental electric tractor prototype traveling on firm soil considering case studies in which the slip control is enabled and disabled. The acquired results demonstrate that the slip control allows for obtaining a more stable performance and reduced energy consumption.

Analysis of lithium-ion thermostabilization systems traction batteries of electric vehicles

Problem. The paper solves an important scientific and practical problem that allows to increase the competitive advantages of agricultural producers through the use of modern energy-efficient tractors with electric transmission. The control system of the traction electric drive is a component of the modern electric tractor of the fourth traction class which has become the most widespread and is intended for providing movement in the modes of various loading. The study of electric motors of a modern electric tractor of the fourth traction class is carried out. The electric motor is characterized by input and output parameters, internal parameters or state parameters, external influences. Methodology. The methods of theoretical basic electrical engineering have been developed in the production and calculation of circuits. Also classical methods of statistics of signals from ADC are used. Results. The technique of processing information from the current, voltage and temperature sensors using a mathematical apparatus without using harmonic analysis is presented. The hardware implementation of the proposed method allows the use of simplified computing tools. Originality. Complex analysis of the data obtained from the current, voltage and temperature sensors is carried out. During the analysis, the range of velocities with stable operation of the measurement system was determined. Based on the data obtained, it is concluded that the use of a horn antenna as a concentrator substantially eliminates lateral interference and extends the range of possible velocity measurements. It is shown that the level of sampling significantly affects the upper limit of the measurement speed. Practical value. It is shown that: As a result of the work, an important scientific and practical problem was solved, which allows to increase the energy efficiency of tractors through the use of tractors of the fourth traction class electric drive. To maintain the maximum energy efficiency of the traction electric drive of the tractor in the modes of various loads, its control system must include means of displaying the current state of the energy parameters of the power plant. The electrical equipment must include an on-board computer, which helps the driver to make the optimal tasks of work, according to preliminary calculations, as well as display the information needed on the route, the state of the vehicle, means of communication. communication of the car with the external environment, with the navigation system, etc. The on-board computer provides information to the touch screen with programmable virtual controls, and communicates with the driver's mobile systems. The study of electric motors of a fifth traction class electric tractor was carried out. As an object of motor control, it is characterized by input and output parameters, internal parameters or state parameters, external influences. An algorithm for selecting the parameters of the traction motor system has been developed and a circuit implementation of the control system has been offered.

Artificial neural network to predict traction performance of autonomous ground vehicle on a sloped soil bin and uncertainty analysis

• ANN models were developed to estimate the AGV’s traction behavior on slopes. • Uncertainty analysis quantified the reliability and robustness of ANN model output. • ANN is a promising, robust, and reliable method to predict off-road vehicle’s traction performance. • Predictive traction models would empower the multi-AGV’s operation on a high slope. A fleet of autonomous ground vehicles (AGV) is envisioned to expand farming to arable land suitable for production except for being too steep for conventional equipment. The success of proposed multi-AGV system largely depends on the traction performance of the individual AGVs on unevenly sloped terrain and optimization of the AGVs control variables. Therefore, the drawbar pull performance of a prototype AGV was evaluated in a soil bin at varying slopes, speeds, and drawbar pull (DP). The AGV’s traction performance was expressed in three metrics: tractive efficiency (TE), travel reduction ratio (TRR), and power number (PN). Optimizing the control variables is intricate and ill-defined, which requires an accurate model to predict the performance of the proposed multi-AGV system. Hence, this study aims to design an artificial neural network (ANN) to estimate the traction behavior of the AGV on a sloped testbed as a function of AGV’s speed, applied DP, and slope. A multi-layer perceptron feed-forward ANN architecture with a single hidden layer trained with a back-propagation algorithm was adopted. A series of ANN models with increasing complexity and different hidden layer activation functions were developed for each response variable, i.e., ANN-TE, ANN-TRR, and ANN-PN. A re-sampling-based method, K-fold cross-validation, was employed to estimate the model generalization error. The model success was evaluated via Mean Squared Error (MSE) and the Coefficient of Determination ( R 2 ) against a test set. The final predictive model was trained on the entire data set, and the observed R 2 was 0.933, 0.882 and 0.858, respectively, for ANN-TE, ANN-TRR, and ANN-PN. Subsequently, a Monte-Carlo Simulation based uncertainty analysis was carried out to demonstrate the model strength and the degree of uncertainty by constructing a 95% prediction interval. This study shows ANN as a promising, robust, and reliable method to predict traction performance in agricultural tillage-traction studies and developed models can empower the multi-AGV system on steep-uneven slope terrain.

ПРИМЕНЕНИЕ ШИН УВЕЛИЧЕННОЙ РАЗМЕРНОСТИ, КАК СПОСОБ ПОВЫШЕНИЯ ЭФФЕКТИВНОСТИ РАБОТЫ МАШИННО-ТРАКТОРНОГО АГРЕГАТА

It is known that one of the most effective ways to improve the traction performance of wheeled vehicles is to increase the area of contact between the propeller and the supporting surface. The performance indicators from the use of tires of increased dimension are presented, by reducing the level of unproductive losses for self-movement, slipping and processing of over-compacted soil along the tire track. The results of comparative assessments of traction and operational and technological indicators of the T-150K tractor on plowing with serial tires of dimension 21.3R24 and tires 66x43R25 with DW36x25 disks are presented. As a result of the study, an increase in the traction efficiency of the tractor on a stubble background by 11 - 44.5% was obtained. An increase of 1.36 times in the traction force developed by the tractor compared to the serial version with a slipping level of 15% was obtained. Comparative evaluation of performance indicators found that when working with a 5-furrow plow, the performance of the unit with 66x43R25 tires was 40% higher than that of the serial sample, and per hectare fuel consumption was 38% lower. When working with a 4-furrow plow, the differences in productivity by options amounted to 36%, and specific fuel consumption - 32%.

Determining the influence of geometric parameters of the traction-transportation vehicle's frame on its tractive capacity and energy indicators

This paper reports results of studying the influence of geometrical parameters of the frame in a traction-transportation vehicle on its traction and energy indicators. A method for estimating the influence of geometrical parameters of the frame in a traction-transportation vehicle on its traction and energy indicators has been substantiated, based on the traction calculation of the tractor and taking into consideration the change in the distance from the hinge of the traction-transportation vehicle to the front and rear drive axles. The method makes it possible to determine the normal reactions, tangent thrust forces, and traction power on the wheels of the machine. The method reported here enables defining the optimal geometric parameters for improving the traction-adhesion and fuel-economic indicators of the traction-transportation vehicle. It was theoretically established that the normal reactions on the front wheels of the studied traction-transportation vehicle are 27,800 N and exceed by 1.95 times the normal reactions on the rear wheels of 14,200 N. This is due to the fact that the distance from the hinge to the corresponding axles of the wheels is 1.89 m and 0.97 m. Increasing the distance from the hinge to the axle of the rear wheels to 1.17 m produces a positive effect on improving the tractive performance of the traction-transportation vehicle. There is an increase in the tractive power on rear wheels to 24.39 kW. The experimental study of the traction-transportation vehicle was performed using an all-wheel-drive machine with a hinge-connected frame as an example. The maximum traction power is 121 kW, which is achieved at a speed of 12 km/h, traction efficiency of 0.68, and a thrust force per hook of 30.2 kN. The difference between the results obtained theoretically and experimentally is 8 %. Applying the method could make it possible to provide designers and manufacturers with recommendations for the construction and improvement of a traction-transportation vehicle, to improve traction and adhesion properties, and reduce the anthropogenic impact on the soil

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.

Analysis of the Effect of Tillage Depth on the Working Performance of Tractor-Moldboard Plow System under Various Field Environments.

The purpose of this study was to analyze the tillage depth effect on the tractor-moldboard plow systems in various soil environments and tillage depths using a field load measurement system. A field load measurement system can measure the engine load, draft force, travel speed, wheel axle load, and tillage depth in real-time. In addition, measurement tests of soil properties in the soil layer were preceded to analyze the effect of field environments. The presented results show that moldboard plow at the same tillage depth had a wide range of influences on the tractor’s working load and performance under various environments. As the draft force due to soil–tool interaction occurred in the range of 5.6–17.7 kN depending on the field environment, the overall mean engine torque and rear axle torque were up to 2.14 times and 1.67 times higher in hard and clayey soil, respectively, than in soft soil environments. In addition, the results showed tractive efficiency of 0.56–0.73 and were analyzed to have a lugging ability of 67.8% with a 44% maximum torque rise. The engine power requirement in hardpan was similar within 3.6–9.6%, but the power demand of the rear axle differed by up to 18.4%.

Fatigue Analysis of Spike Segment of Special Tractor Wheels in Terms of Design Improvement for Chernozem Soil

The driving wheels affect the tractive efficiency, fuel consumption, and soil compaction. This study presents the fatigue analysis of a spike segment that is the main part of an innovative driving wheels designed to improve tractor tractive performance. The design improvement was proposed for Chernozem soil allowing the full penetration of spikes. The spike segment was loaded by forces resulting from the maximum drawbar pull at 100% wheel slip and penetrometer resistance. A drawbar pull increase caused by the spike tires was also calculated. The experiments were performed using a subcompact tractor in the first gear on a grass field at soil moisture 18.8%. Gerber theory was used for the fatigue analysis performed using ANSYS software. The dependances of the safety factor on the horizontal rod diameter and the number of load cycles was constructed. The safety factor of 1.73 calculated for the spike segment made of steel S355 is suitable for the reduction of the actual horizontal rod diameter (12 mm). The fatigue analysis showed a safety factor of 1.28 at 100,000 load cycles in the case of a reduced diameter (10 mm). A diameter of 8 mm was also simulated, but the calculated safety factors do not allow it in terms of safe operation.

Electrical Aircraft Ship Integrated Secure and Traverse System Design and Key Characteristics Analysis

The shipborne helicopter is an essential maritime combat force of the modern navy. However, as the most advanced shipborne helicopter landing assistance system, the ASIST still suffers from the significant disadvantage of the uncontrollable driving speed of the claw. This paper aims to propose an implementation scheme of the EASIST transmission system by selecting an asynchronous motor as the direct power source to solve the problem. On this basis, the speed controller is built by combining the vector control algorithm with an ANFIS control algorithm. In addition, the capture and traction characteristics of EASIST are analyzed, and the capture track of the claw and the maximum load in the traction process are obtained. Finally, the dynamics model of the transmission system is established by power bond graph theory, and the system simulation test is carried out. Simulation results show that the proposed EASIST reduces the capture time by about 60% and dramatically reduces the capture speed. And when towing the shipborne helicopter, EASIST can keep a good speed-tracking effect under the action of wildly varying load force. The research results of this paper are of great significance to broaden the application scope of ASIST and improve the traction efficiency, which plays a vital role in enhancing the combat effectiveness of shipborne helicopters.

Measuring Method of Slip Ratio for Tractor Driving Wheels Based on Machine Vision

Tractors are prone to large slips when they are in field operation. The degree of slip plays a vital role in traction efficiency and fuel efficiency. This paper presents a method for measuring the slip ratio of tractors in field operation based on machine vision. The accurate measurement of slip ratio needs to obtain actual velocity and theoretical velocity separately. For obtaining the actual velocity, a monocular camera mounted on the tractor vertically faces down at the ground to collect images. Then, the feature points of inter-frame ground images are matched by the ORB (Oriented FAST and Rotated BRIEF) algorithm for calculating the translational displacement. Next, a homography matrix based on camera calibration is proposed to complete the transformation of a point from the pixel coordinate system to the world coordinate system. Aiming to acquire the theoretical velocity, a method that takes the variations in tire radius into account is proposed, and the tire radii of the driving wheels are indirectly determined by the tire inflation pressure in real-time. The proposed measurement method was verified with an experimental tractor. The results show that the mean absolute errors of the tractor driving wheels’ slip ratio measured by the machine vision method are less than 0.75%, and the maximum of the absolute errors is not more than 2.22%, which shows good performance.

The use of small-sized tractors in agriculture

The most complex and expensive machines on the agricultural machinery market are tractors and combines. The number of agricultural tractors produced in Russia in 2019 amounted to 3,798 units, but only 38.7 of them are domestic, and 61.3% are foreign cars assembled in Russia. All tractors are classified according to purpose, type of propulsion unit and type of frame. By the type of mover, wheeled and tracked tractors are the most common. Wheeled tractors are easy to manufacture, operate, maintain, have a lower cost, and are more versatile. Caterpillar tractors, in turn, are more effective on waterlogged and loose soils, since, due to the larger support area, they have less impact on the ground. The share of small-scale enterprises in gross agricultural production in 2020 increased to 14.3% due to the implementation of state programs for the development of small agribusiness. This category of farms produces about a third of the total volume of grain - 39.4 million tons. Despite the significant role of small-scale enterprises in the agricultural economy of Russia, this category of farms is not sufficiently provided with the necessary agricultural machinery, such as small tractors with the necessary attachments. Moreover, the demand for domestically produced mini tractors is growing every year due to their versatility, operational reliability and ease of maintenance. The lack of mini-tractors in the consumer market forces farmers to use tractors of traction class 1.4 and 2 in the production of products, which leads to excessive pressure on the ground, its overcompaction and destruction of the structure. In addition, on small-area fields with difficult terrain for the operation of equipment, it is impossible to fully implement the efficiency of tractors of this traction class. These factors substantiate the need for further development and manufacture of mini-tractors, taking into account existing global trends, such as the use of artificial intelligence, which includes decision support systems, expert systems, autonomous robots and robotic systems, as well as unmanned units.

Intelligent ballast control system with active load-transfer for electric tractors

For agricultural tractors fixed ballast cannot provide high-efficiency traction under time-varying resistance in the field. Combining the characteristics of electric tractors with high-weight battery packs, this paper develops an intelligent ballast control system including a battery position adjustment (BPA) mechanism and an active ballasting control method. A tractor traction performance prediction model was developed to predict traction performance parameters and load-transfer in real time. The movement of the battery pack enables load-transfer based on the BPA. To ensure the lowest sliding rate of optimal tractive efficiency, an active ballasting control method based on a particle swarm optimisation algorithm was proposed that enabled control of the optimal battery position. The results of MATLAB/Simulink simulation indicate that the traction resistance after grading and pre-treatment not only reduced the frequency of change in the resistance signal but also retain the original trend. The results of a hardware in the loop test showed that the average tractive efficiency in the mode of active ballasting mode higher than that of the no ballasting mode (increased by 6.6%) and fixed ballasting mode (increased by 4.7%). The mean wheel slip in active ballasting mode was lower than that of the no ballasting mode (decreased by 10.3%) and the fixed ballasting mode (decreased by 4.9%). In addition, the front axle dynamic load distribution ratio in active ballasting mode was always greater than 0.2, which ensured the operational stability of the tractor. This study provides theoretical support and technical reference for optimising the traction performance of electric tractors. • An intelligent ballast control system with active load-transfer is developed. • The concept of batteries instead of ballasts. • Battery position adjustment mechanism (BPA) is designed. • Active ballasting control method based on traction performance prediction model. • The maximum average tractive efficiency is increased by 6.6%.