Aiming at the problems of poor adaptability and low operational safety of agricultural machinery in hilly and mountainous areas, this study conducts the design and experimental research on a high-precision autonomous positioning system for the multi-crop combined harvester. The Beidou and Inertial Measurement Unit (IMU) high-precision positioning system based on Network Real-Time Kinematic (NRTK) was designed, and the hardware selection and software development of the autonomous positioning system were completed. The NRTK fixed base station in complex field environments was deployed Based on 4G communication, and dynamic differential calculations were performed with the random positions of the machinery to accurately obtain positioning data. Using the STM32L475 chip as the core information processor, efficient processing of real-time position information of combined harvester was realized based on coordinate conversion and attitude error correction of the autonomous positioning system. Performance tests were carried out using a selfdeveloped the combined harvester. The results show that: the positioning error of the designed autonomous positioning system is less than 2 cm; when the harvester's speed ranges from 0.4 to 1.2 m/s, the maximum speed measurement error is less than 0.05 m/s, and the average speed measurement error is approximately 0.014 m/s, which meets the autonomous positioning accuracy requirements of the machinery.

Aiming at the adaptability and safety problems of agricultural machinery in hilly and mountainous areas, the remote driving control system of agricultural full hydraulic chassis is designed based on ARM-Linux platform. The whole remote driving system is composed of Web upper computer, server system and chassis drive system. According to the requirements of chassis operation, the STM32F407 is used as the lower computer to realize the running control and motion status monitoring of the chassis. Taking the I.MX6ULL as the hardware platform, the Linux as the software platform, and 4G communications as the Web Server, the remote driving of the chassis is realized through Web pages on the computer. It can be seen from the test results that the minimum RTT delay from the Web page driving to the lower computer is 170 ms; the maximum RTT delay is 1310 ms, and the average RTT delay is 222.75 ms. The real-time interactivity of the control system meets the needs of remote driving of the agricultural machinery. The research provides a theoretical basis and technical reference for the development of the remote driving system of the agricultural machinery.

In order to improve the automation level of the crawler tractor leveling system, an adaptive leveling control system was designed for the developed crawler tractor leveling device. The overall hardware of the leveling control system was determined and the software system of the leveling device was designed using the proportional algorithm. The designed leveling control system is composed of the real-time detection part, control part, driving part and display part. The system can realize the real-time detection of the tractor inclination angle, and complete rapid leveling of the leveling device. The test results of the leveling control system show that the leveling accuracy and leveling time of the lateral and longitudinal slope increase with the increase of the tractor inclination angle. The leveling accuracy and stability of the longitudinal slope are better than that of lateral slope leveling, and the leveling speed is higher than that of the lateral slope. The coordination leveling accuracy is higher than the independent leveling accuracy of the lateral slope and longitudinal slope, and the collaborative leveling accuracy of the longitudinal slope is better than that of the independent leveling accuracy. The developed leveling control system can independently complete the leveling work under the actual working conditions of the crawler tractor. The leveling accuracy can be in 1° and the leveling time is in 0-6 s. The leveling accuracy and time can meet the design requirements.

In view of the problems of the output power and operation, when the multi-function machine in hilly and mountainous areas driving in the field, the hydraulic control drive system of small multi-function agricultural hydraulic chassis is designed. The key components of the hydraulic drive system were selected and matched. The hydraulic system simulation model was established in AMESim simulation analysis software, and the dynamic analysis of the hydraulic system operation under different conditions is carried out. The simulation analysis results show that the hydraulic system has a large impact and vibration when it is started instantaneously, and the hydraulic system has smaller impact and vibration when it is started stably. It is consistent with the actual working state of the hydraulic chassis. Under the two starting controls, the maximum flow of the hydraulic pump is 50L/min, the motor torque is about 440N • m, and the motor stable pressure is 6Mpa, the motor speed is 96 r/min, which is within the bearing range of the hydraulic components. The simulation output parameters are basically consistent with the theoretical calculation results, and meeting the design requirements. The chassis performance test results show that the maximum crossing height of the chassis is 200mm, the crossing width is 300mm, the maximum deviation of high-speed straight driving is 2.57m, it can stably pass 20° slope, and the operation is stable and the steering is flexible. All performance parameters can better meet the requirements of chassis operation in hilly and mountainous areas.

Garlic harvesting is an important part during the garlic production process. Currently, the major obstacles of the garlic industry development are labour intensity, high farming time, significant losses and low efficiency. According to the characteristics of garlic cultivation in China and based on the current design experience, a half-fed and self-propelled garlic harvester, suitable for garlic producing within most areas of China, was developed. The main working parts contain the devices of stalk-dividing, stalk-lifting, stalk-clamping and conveying, clod-removing, align-cut seedling, as well as garlic collecting system, etc. To ensure the digging effect and improve working quality and stability of the machine, the combined working principle of digging and lifting has been adopted. The functions of garlic align-cut device are to align garlic and cut garlic from seedling; the handle length of cut garlic is accordance with production requirements at the same time. Through the field performance test of the garlic harvester, the operation performance is tested for stalk lifting device and align-cut device in different operating conditions. The operating performance in field is assessed through testing the machine's key performance indicators for different operating speeds. Solutions were suggested after analysing the main causes that impact its operating performance. Testing results showed: the machine has good manoeuvrability and high working efficiency; garlic loss rate <= 1.8%, garlic picking broken rate <= 2.1%, containing soil rate <= 12.8%; all the performance indexes met the design requirements.

In order to improve the production efficiency of peanuts in China and increase the yield,a kind of adjustable air suction seeder with plug board is designed for peanut seeding. The seeder is designed for efficient seeding of large seeds such as peanuts. This structure can quickly finish the replacement of the top block during the machine sowing process,and then to achieve the adjustments of seeding rate and seeding spacing of different crops.

This paper designs the straw collecting box of the corn harvester, which is used to recover the corn straw. In the process of harvesting the corn harvester, the device can be able to complete the task of straw collection, which can effectively reduce the labor intensity of the straw recycling, improve the efficiency and quality of straw recycling. Through the virtual prototyping technology, the design of the whole structure of the straw collecting box is completed.

Structure characteristics and cavitations principle of precise dibbler are elaborate, and the mathematical model of the motion trajectory of the dibbler and parametric equations of punching contours are also established in this work. On the basis of parametric equation between punch length and wheel parameter, the effect of dibbler’s radius、fixed duckbill inclination angle 、flexible duckbill inclination angle and the slip ratio to punch length are analyzed, meanwhile in combination of field testing results the effect of wheel parameter toward cavitations size are analyzed in detail. The research results will provide reference for optimal design of the punching planter and for the research and development of new type of sowing wheel.

According to the problems that caving device of the mulching film and punching planter that hard to adjust the plant distance problem and the low frequency of use at present, the plant spacing adjustable dibbler was designed for continuously adjustable planting distance of the caving device. The adjustable dibbler can be realize continuous adjustable of plant spacing in certain range, when the planter was working. It is to achieve the aim of a machine used several purposes, expand the scope of use, and improve the frequency of use. By the UGNX virtual prototyping technology, completed the design of the overall structure of the adjustable dibbler. The study provides reference for the design and development of the mulching film and punching planter.

At present the Maize picker has the large power consumption problem. The paper design a Maize picker device, the device is effective to reduce the power consumption of corn harvest machine work. By the virtual prototyping technology, completed the design of the overall structure of the Maize picker device.

According to the technology requirement and existing problems of the key working parts (punching device) of the peanut mulching film and punching planter, the punching device of the peanut mulching film and punching planter was designed adapt to first mulching film and then sowing. It was introduced the structure and working principle of the punching device, and the punching mechanism are studied. The trajectory of the punching parts was analyzed in the punching process, and the parameter equation of the punching profile was established. On the basis, the main structure parameters of the punching device were analyzed and optimized. The study provides reference and basis for the design and development of the peanut mulching film and punching planter.

Brake problem for a small multi-function chassis of southwest hilly region, design a set brake device, especially suitable for walking speed slow small crawler chassis. The braking device has the advantages of simple and compact structure, light weight, convenient, simple and flexible operate, reasonable use spaces etc. . Through the braking test, proved that the brake braking performance is good, fully meet the requirements of the agricultural machinery braking performance.

Based on the path and collision-free that welding robot should do in the period of machining, a trajectory plan for certain collision-free movement for robot is provided in this paper. The first is searching the collision-free path through subdivision the working space by tangent plane projection in concentric cylinder coordinate system. The second is to assemble the welding robot with three degrees of freedom in order to confirm the collision-free trajectory when welding. Finally, obtain the optimized path by software simulation. Copyright © 2013 IFSA.

This paper designs a new type of the crawler chassis brake system, which is suitable for crawler travel system slow walking speed. Characteristic of braking system has simple and compact structure, light weight, flexible use, convenient assembly and disassembly, large braking force, good braking effect, etc., can solve small crawler chassis brake problem very well.

The failure of the underframe is one of the most important factors affecting the service life of the multi-function chassis. This paper established a virtual model of multi-function chassis by UGNX 3D software; The use of the finite element analyzed model, find the weak link of underframe, and effectively reduce the underframe weight, determine the optimal scheme. Based on the underframe structure design to create the underframe prototype, and passed the test to prove the prototype running smoothly, safe and reliable.

In view of the present agricultural machinery manipulation device of large space occupation, low control precision. In this paper, design a set of steel rope control small multi-function chassis motion manipulation device. By virtual prototype technology, completed the design of the whole structure of controlling device and key components of virtual design.

At present the duckbill seeder has small use range, the low frequency of use, hard to adjust the holes distance problem, design the hole distance adjustable mechanism for continuously adjustable planting distance of duckbilled seeder . The mechanism realizes seeder certain range continuous adjustable distance, to achieve the aim of a machine used several purposes, expand the scope of use, improve the frequency of use. By the virtual prototyping technology, completed the design of the overall structure of the holes distance adjustable device.

Based on basic principles, operational requirements and key parameters of Seed Rope Direct Sowing Machine(SRDSM), the machine was designed and developed. The structural design of the anti-blocking device, sowing device, opening device, banking device, compacting device and assembly of the seed rope direct sowing machine, have been finished with the assistance of UG. The manufacture and testing. of the prototype were carried out. Field test results showed: the machine has good maneuverability and high working efficiency, sowing effect is to meet the operational requirements, and effectively solved the problems of the easy plugging of opener and adjusting difficulty of the numbers of seed in every hole. It provide reference for the research and development of such equipments.