| The hilly area has great potential for agricultural economic development.However,due to the special landform of fragmentary plots in the field,the large and medium-sized agricultural machinery are unable to enter the field for operation,and the demand for small mountainous agricultural machinery is strong.The crawler chassis,which has excellent performance such as low ground pressure,flexible steering and good maneuverability,can be regarded as a kind of optimal scheme for small mountain agricultural machinery power chassis.At present,the research and development mode of tracked chassis is dominated by the traditional mode,which is difficult to adapt to the rapidly changing market demand.Therefore,the research on the driving performance of small mountain tracked chassis and its influencing factors based on virtual prototype technology has important theoretical significance and demand background.Based on the topography and geomorphology of the hilly areas,this paper prototyped a small mountain crawler chassis,and used the combination of theoretical analysis,numerical simulation and experimental research to study the driving performance of the crawler chassis and its influencing factors.The main research work of this paper is:1.Combined with the characteristics of terrain and landform in hilly and mountainous areas and the test requirements,the design requirements for the crawler chassis test platform were put forward,and the design scheme of crawler chassis was determined on the basis of referring to the existing crawler chassis structure.According to the design indexes,the structure design and model selection calculation of the crawler chassis' s walking device,power system and overall machine layout are carried out,and the static analysis of the key bearing components is carried out to verify the bearing capacity of the chassis.On this basis,the trial production of crawler chassis is completed,which provides a platform for the real vehicle test.2.Combined with the test requirements of the crawler chassis,the test parameters such as driving speed,driving wheel speed,torque and tension are determined,and the corresponding test system is set up,the test scheme is designed,and the actual vehicle test and data collection are completed under four working conditions: idling,straight running on hard road,straight running on soft road and climbing road.3.Based on the analysis of kinematics and dynamics for the main working conditions of the crawler chassis,the multi-body dynamics model of the crawler chassis was established with the help of the multi-body dynamics software RecurDyn.The effectiveness and reliability of the model were verified by the results of the real vehicle test.Real vehicle test and simulation analysis of the comparison results show that the no matter in the rigid pavement or on the soft road environment,caterpillar chassis average driving speed,driving rotary torque and track parameters such as tension has good consistency,the relative error is not more than 5%,indicating that the established crawler chassis multi-body dynamic model is effective and credible,can objectively reflect the dynamic characteristics in the process of crawler chassis drive.4.Based on the established multi-body dynamics model of the crawler chassis,the driving performance of the crawler chassis when it goes straight,turns,climbs and surmounts obstacles is simulated and analyzed,and the influence of the crawler pre-tensioning force,soil parameters,driving speed and the position of the mass center on its driving performance is studied.The results show that: for this type of crawler chassis,the appropriate crawler pretensioning force is 70% and 80% of the weight of the whole vehicle;The smoothness and lateral stability of hard road are slightly worse than that of soft road,but the steering stability is better.Can run on the slope stability of the slope is less than 20 °;The limit obstacle height of hard pavement and clay pavement was 366 mm and 411 mm respectively,and the limit obstacle width was 877 mm and 827 mm respectively. |
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