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Ride comfort is of great importance feature for the heavy truck, its optimization can improve the driver's driving conditions to reduce fatigue, and make the goods safer. Primary factors that can influence ride comfort are form and parameters of suspension, which are suspension stiffness, suspension damp and their combination. When the form of suspension is confirmed, more reasonable parameters can be selected by optimization method to improve ride comfort. Ride comfort optimization analysis belongs to the combinatorial optimization problem, at the same time, the nonlinear characteristics in optimization is essentially a nonlinear multimodal optimization problem. In this paper, at first, a nine degree of freedom vehicle vibration model was established; Vehicle driver seat acceleration simulation tests were conducted with different vehicle speed. Also, both time and frequency domain analysis was implemented with MATLAB software development platform. On the whole, with the increase of the speed of the vehicle, the acceleration root mean square of vehicle driver seat became larger, so the vehicle ride comfort performance reduced. Especially at low speed and high acceleration change is more obvious. But in 40~80 km/h, the acceleration change quite gentle. That means to achieve the better economy and the vehicle ride comfort performance, the vehicle speed keeping in a medium speed is better. Based on C level road and the speed of 70 km/h, with an eight by four dump truck as experimental object, the ride comforttests were conducted, moreover the test results compared with the results of simulation. The compared results showed that the simulation and the test were very close. And then, today technology was coming to a stage of intersection, infiltration, and interaction with multi subjects. More and more issues on complexity, non linearity, and system have come to us. To deal with such complexity of system, conventional techniques have become incapable, and to seek an optimization algorithm, which adapt to large scale parallel with intelligent characteristics, has been a primary research target of related subjects. The artificial fish algorithm was proposed to optimize ride comfort. The artificial fish swarm algorithm (AFSA), anew method based on animal behaviors and the typical application of behaviorism artificial intelligence, was proposed byan internal scholar in recent years. It used the operators such as prey, swarm, follow and random behavior. The algorithm parameters, such as population, step size, sense of distance, the largest try number, crowded degree coefficient and the largest number of iterations, has a great impact on the performance of the convergence. At the end, the artificial fish algorithm was used to optimize ride comfort by reasonable selection of the suspension parameters. The objective function was the acceleration root mean square of vehicle driver seat to be minimized. The decision variables were front suspension stiffness and damp. Moreover AFSA need to set up the appropriate algorithm parameters. For example, population scale, step size, sense of distance, the largest try number, crowded degree coefficient and the largest number of iterations was 100, 100, 20 000, 100, 9 and 50. Where the population scale N was called the number of possible values of suspension parameters within the value range, step size was suspension parameters increasing or decreasing the amount of each iteration, and sense of distance visual was variables scope of each iteration. Optimization results show that the acceleration root mean square average fell by 16.82%, the biggest fell by 21.24% in 60 km/h, so it effectively improves the ride comfort h performance of heavy vehicles. [ABSTRACT FROM AUTHOR]

The hydraulic steering-by-wire system abandons the mechanical connection between hand wheel and front steering wheels, and thus the driver′s intent is delivered via electrical signal. The actuator of hydraulic steering by wires system is the hydraulic cylinder. ECU (electronic control unit) generates the corresponding electric current to control the opening of electro hydraulic proportional servo valve after receiving the steering signal, which correspondingly leads to the displacement of steering hydraulic cylinder. The displacement direction determines the steering direction and the magnitude determines the steering angle. At present, asymmetric hydraulic cylinders are mostly adopted. However, due to the piston areas are varied as the piston rod moves in different directions, even if the opening of electro hydraulic proportional servo valve and the pressure are fixed, the displacements of the piston rod vary under stretch and retracting condition. Combining hydraulic steering by wire system with asymmetric hydraulic cylinder, we know that accuracy adjustment of steering is essentially the adjustment of the hydraulic cylinder piston rod's displacement on the left or right side. Therefore, the traditional PID(proportional integral derivative) control of hydraulic steering by wire system is not efficient for precise control of steering angle. Considering the error is either positive or negative in steering angel, to improve control accuracy, the hydraulic cylinder can be regarded as different hydraulic cylinders with different piston areas working alternately. This paper presented the idea of dual channel PID control, in which way the 2 hydraulic cylinders (positive or negative error) used different channels with different PID parameter values. The characteristic of dual channel control was that when the errors, whose magnitudes were same and positivity and negativity were different, were adjusted with different PID values, the control current of electro hydraulic proportional servo valves was not same. However, the difference of cavity work area finally guaranteed the same displacement of hydraulic cylinder piston rod, namely the accuracy of adjustment. In addition, in order to avoid the low accuracy of a simplified mathematical model as well as the time consuming defect of other software, we used SimHydraulics to build the physical model of hydraulicsteering by wire system conforming to the real platform, whose preferences consulted the reality; the simulation of following response and steering angle pulse test of the steering wheel was completed, the test rig of hydraulic steering by wire system was set up, and then IPA15F2K61S2 chip of STC was chosen, which was written to the dual channel control program to be a controller of the hydraulic steering by wire system platform. The steering wheel angle was the input signal of controller, and the product of the actual angle and the steering ratio was a feedback signal. The output signal of the controller was the current controlling the electromagnetic proportional servo valve. The experiments of the steering wheel were completed under the control of single channel and dual channels on platform; and the effect of dual channel PID control on the system was analyzed by combining simulation and experiment results. Under the dual channel PID control, the simulation results showed that, the following error was 0.473° and the step response time was 0.273 s, the errors indifferent directions were almost the same, and they were both superior to the performance of the traditional PID control, for which the following error was 1.315° and the step response time was 0.334 s. Moreover, compared with single channel PID control, the error of dual channel PID control decreased by 64%, and the response speed increased by 18%. The results of experiments on platform were consistent with the simulation, which indicated that under the control of dual channel PID, the response of hydraulic steering by wire system was faster, the following error was smaller, and the errors in positive and negative direction were almost the same. Thus, it is concluded that the system under the control of dual channel PID has superior following performance and control precision as well as more desirable stability and reliability. [ABSTRACT FROM AUTHOR]

There is a large area of low productive soil, many soil types, and different low productive reasons in Heilongjiang Province. So improving low productive soil has important significance for agriculture. Subsoil fertilization is a comprehensive soil improvement technology which can improve subsoil′s bad physical and chemical properties. Studying team has done research on improving planosol with subsoil fertilization, and this technology has the effect of continually increasing yield, but there is lack of the research on other soil types, and the practical mechanical tools. In this paper, the subsoil fertilization plow was researched according to the subsoil fertilization technology requirements, and applied on the improvement of carbonate meadow chernozem and thin layer black soil, which was aimed to clarify its soil improvement effect on soil physical and chemical properties and corn yield, and provide the mechanical and technological support for its wide application in low production soil. The field contrast method was applied in this study, and 3 treatments were set which included deep loosing(DL), subsoil fertilization(SF) and control(CK). The result showed that the effects of subsoil fertilization and deep loosing on soil physical and chemical properties, yield characteristics and yield were not consistent. The lasting effect of deep loosing and subsoil fertilization on deceasing soil shear strength was obvious. For carbonate meadow chernozem and thin layer black soil, the soil shear strength was decreased by 7.14 and 5.41 kPa under DL treatment, and by 12.16 and 8.20 kPa under SF treatment respectively compared with that of the CK in the first year after soil improvement; the soil shear strength was decreased by 0.68 and 2.25 kPa under DL treatment, and by 6.65 and 11.31 kPa under SF treatment respectively compared with that of the CK in the second year after soil improvement. The bulk density and hardness were the same as the above change. Subsoil fertilization could improve soil air permeability and saturated hydraulic conductivity; the air permeability coefficient was respectively 3.22 and 15.28 times higher than the CK on the 10-30 cm soil layer of carbonate meadow chernozem and thin layer black soil in the first year after improvement, and 5.17 and 3.78 times after the second year; the saturated hydraulic conductivity was respectively 8.93 and 7.68 times higher than that of the CK after the first year, and respectively 12.62 and 3.38 times after the second year. The effect of deep loosing was not obvious. The DL and SF treatment could improve water consumption of subsoil, and the order of water consumption was CK>DL>SF in 0-30 cm soil layer, and SF>DL>CK in 30-60 cm soil layer. The water consumption in subsoil layer was 30% of total water consumption, and 10% more than the CK. The total phosphorus and available phosphorus were increased by 0.05 g/kg and 3.21 mg/kg under SF treatment compared with the CK in 20-30 cm soil layer of carbonate meadow chernozem, and by 0.01 g/kg and 1.92 mg/kg in 30-40 cm soil layer, and the phosphorus offering intensity of the 2 layers was improved by 5.17 and 17 times compared with the CK; The total phosphorus and available phosphorus were increased by 0.09 g/kg and 15.05 mg/kg under SF treatment compared with the CK in 20-30 cm soil layer of thin layer black soil, and by 4.19 g/kg and 4.96 mg/kg in 30-40 cm soil layer, and the phosphorus offering intensity of the 2 layers was improved by 5.17 and 17 times compared with the CK. Subsoil fertilization and deep loosing could promote the corn growth, increase the length and width of ear, grain number per spike, 100-seed weight and yield. The yield was increased respectively by 18.01% and 14.28% under subsoil fertilization and deep loosing in the first year after soil improvement for carbonate meadow chernozem, and respectively by 6.82% and 2.87% in the second year after soil improvement; the increased yield was respectively 6.45% and 1. 80% in the first year after soil improvement for thin layer black soil, and respectively 11.18% and 5.11% in the second year. The effect of increasing yield for carbonate meadow chernozem is more obvious than that for thin layer black soil. [ABSTRACT FROM AUTHOR]

The application of the path tracking technology on agricultural vehicle makes the robot replace farmers for field operation, and the accuracy, production efficiency and dependability about farming automation are improved effectively. Meanwhile the labor time, labor intensity of drivers and the production cost are saved. The path tracking of agricultural vehicle was studied in an operating condition, and a variety of sensors were installed on the car features of the external environment. Then it generated a four-element in state space by the target path which was given for controling the agricultural vehicles to track the target path automaticly according to the theory of optimal navigation control. The location method of GPS/INS was selected, the navigation system was developed, and the experiment was finished in 2014. According to the needs of automatic walking positioning system, a variety of sensors has been chosen, including the inertial sensor, angle sensor and GPS sensor. Then the serial program was writen to collect the signal from the sensors and calibrate them. In order to meet the requirements of vehicle navigation system, the positioning system with low cost and high precision was developed. The hardware of the system consisted of two GPS modules, two Zigbee wireless transmission modules and an inertial sensor. The data from the sensors are filtered and fused, and finally accurate, reliable vehicle position data was got. The tracking controller based on preview control was designed to obtain the future values and target values of the vehicle. With the target path and its curvature, the feed forward control value was got. There was an error between the current state and the state of vehicle target path that was needed to use LQR for elimination. The performance of the path following controller was simulated by Matlab, then the maximum lateral error was 0.16 m and 0.27 m at the speed of 0.5 m/s and 1 m/s respectively. The results showed that the control method was feasible. The steering control system was designed based on steer-by-wire(SBW) after the study of vehicle navigation control principle. SBW removed out mechanical connection between steering wheel and steering front wheel. It used motors to control front wheel angle and simulated force characteristic. Compared with traditional steering system, SBW had characteristics of ideal steering ratio and active steering control according to vehicle state parameters, and improved safety of driving and handling stability. The strategy of BLDCM was designed in order to make actual front angle follow the desired angle better. PID control and sliding mode variable structure control were applied in strategy of BLDCM and the result of simulation showed that sliding mode variable structure control was better than PID control. This paper designed the electronic control unit of SBW based on chip of MC9S12XET256, mainly including peripheral circuit of MCU, CAN communication circuit, drive circuit of BLDCM, power circuit, signal acquisition and processing circuit, current sampling circuit of motor. Based on the requirement of joint simulation, we designed a bench test for control strategy and hardware, software of ECU in 2015. The results of test bench showed that angle correction was similar with the result of simulation and sliding mode variable structure control was better than PID control in following front angle. Finally, the vehicle steering control test and the vehicle path tracking control test were carried out based on vehicle test platform, which was built personally. The vehicle path tracking system was based on the Windows platform, using Microsoft Visual Studio as the development environment. The integrated navigation system was validated and the test data showed that the integrated navigation system had a high positioning accuracy and the steering system had a reliable tracking performance. The final navigation and positioning accuracy of integrated navigation system was around 0.1 m to 0.5 m and the response speed of the whole system was about 0.1s . The results proved that the system could meet the requirements of agricultural vehicle path tracking control system. [ABSTRACT FROM AUTHOR]

Although great development has taken place in agricultural mechanization since reform and opening up, China still faces the big challenge in improving agricultural resource utilization as well as promoting the sustainable development of agriculture at present. As we all know, it is mainly the 5 factors, i.e. water, soil, fertilizer, pesticide and seed that affect sustainable development in the construction of China’s agricultural modernization. The overall development of agriculture in China will be impeded if the resource utilization stays low. There exist some phenomena: 1) the irrigation water use is 360 billion m3 each year, while canal-system water use efficiency is only 0.4~0.6; 2) high-quality cultivated land is lacking; 3) nitrogen use efficiency is about 30%~35%, which is 20% less than developed country; 4) pesticide utilization is merely about 30%, while leads to severe environmental pollution; 5) the demand of seeding quantity is high while there are shortage of high-quality seeds and serious waste of seeds. Accordingly, several technologies and machines in PA (precision agriculture) were put forward in this article so as to meet the requirement of agricultural sustainable development: precision irrigation, precision plow, precision fertilization, precision spraying, and precision sowing. By reviewing the researches at home and abroad, the current situation of PA was analyzed and thus the methods to achieve the 5 mentioned key technologies were presented. Meanwhile, some other suggestions were proposed to push the agricultural mechanization to play a greater and more important role on the utilization of agricultural resource and agricultural sustainable development: 1) further strengthen the combination of agricultural machinery and agronomy as well as the basic study of related theory; 2) carry out in-depth studies on key technologies of maximum utilization of agricultural resource, especially in precision irrigation, precision plow, precision fertilization, precision spraying, and precision sowing; 3) enhance the capacity of independent innovation, namely, the capability of equipment design and manufacture related to PA; 4) accelerate extensive application of precision agricultural machine and equipment. Above all, this paper has provided a scientific guide and policy direction for improving utilization of agricultural resource, promoting agricultural mechanization and agricultural sustainable development. [ABSTRACT FROM AUTHOR]

A flexible chassis is a four-wheel-independent-drive and four-wheel-independent-steer electric vehicle chassis with 4 driving wheels. It can make omnidirectional motions and every driving wheel has an offset steering shaft, which means the rotating surface of the wheel is not coplanar with the steering axis, so that the chassis can make a turn using the force of the wheel. This paper presented a new type of test bench, which was built based on the working characteristics of the driving wheel, in order to resolve some key issues about the dynamics of the driving wheel based on offset steering shaft. The feature of this bench was that steering center of the offset shaft shared the same axis with the center of horizontal turntable below the wheel to simulate its moving on the ground. And a force sensor was connected between the forks of the wheel and the frame of the bench. The force analysis showed the traction force and the power for the steering of the offset shaft. And a record and display software was designed for the bench based on Visual Basic 6.0. First, we completed the whole structure design and analyzed the working principle of the device. Horizontal rotary table drove by the same driving wheel was installed, and its rotary center was the same axis with the steering shaft of the driving wheel which was connected to the frame through the bracket; the sensor was used to test the traction force of the driving wheel moving on the horizontal turntable, and keeping its levelness was supported by 4 small wheels connected to the frame. Second, a test system based on Visual Basic 6.0 was developed to show and record the data of the rotation speed, current and force. And according to the working characteristics of this bench, we analyzed the forces for the driving wheel and its fork, and a model was built and the simulation was carried out based on MATLAB/SIMULINK to make a comparison with the test data. Finally, by testing the bench, we recorded variables, such as the time, rotation speed and current of the driving wheel, and the force of force sensor. We tested the performance of the driving wheel on the bench through loading different weights on the wheel. We analyzed the indices such as the force changing progress and the time spent by stabilization of speed. The result showed that the time spent by the rotation speed of driving wheel changing from zero to stable value was not irrelevant with loading; it was 0.667 s on average. And the force, which could supply power for the offset shaft to steer, had linear relationship with loading. And when the 500 N loading was applied, the turning force was 77.24 N. The various performance indicators met the design requirement, which could make the performances satisfy the requirement of flexible chassis. The test results can provide the reference for the study of flexible chassis and also prove that the bench is feasible and efficient. In addition, the research provides the theoretical and technical references for the control design of four-wheel-independent-drive and four-wheel-independent-steer vehicles. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)