Establishment And Solution Of The Optimal Design Model Of Tractor Steering Trapezoid Mechanism

Agriculture is China’s primary industry,as a basic industry to support China’s development of social and economic,agricultural mechanical operations can improve land yield and labor productivity,but also transfer labor force,reduce labor intensity,improve the ability to resist natural disasters,increase farmers’ income and ensure the quality of agricultural products.Tractor is self-propelled power machine that used for pull and drive all kinds of operating machinery to complete the mobile operatio.Its performance directly affects the qualit y of agricultural operations because it is the main tool of agricultural production and transportation.The front wheel steering widely used agricultural wheeled tractor,and at the same time with the integral steering trapezoidal mechanism.As the main component of steering system,tractor steering trapezoidal mechanism’s design directly determines the performance of tractor in turn,also has a large influence on the dirigibility of tractor,driving comfort and safety and the service life of steering wheel.Therefore,this paper carries out research on the optimization design of tractor steering trapezoid mechanism.According to ackerman’s principle,when the tractor turns,each steering wheel should rotate around the same instantaneous center to ensure that each steering wheel is rolling without sideswipe,but the actual situation often can’t satisfy this requirement.This paper analyzes the movement of tractor integral steering trapezoid mechanism under ideal and actual conditions.Take the sum of the error’s square between actual steering angle of the steering wheel and theory angle of the steering wheel within the scope of turn is minimum as the objective function,and considering the use condition of tractors and other vehicles is different,because trac tors except on the road still need to work in the field,puts forward a new weighting function that more in line with the actual working condition of tractor.Finally establish the mathematical model for optimal design of steering trapezoidal.In order to solve the optimization model,the traditional real number genetic algorithm is improved.The improved algorithm adopts the evolutionary strategy of twice elite retention.And the repetitive individuals in the population are eliminated to ensure the divers ity of the population.In terms of selection operator,the group selection operator is used to enlarge the distance between the two parent individuals to enlarge the diversity of the population.In the aspect of crossover operation,a new crossover operator based on plane vector rotation is proposed.This operator can produce the offspring that are closer to the optimal solution through more detailed exploration of the search area,and make multiple offspring compete then retain the outstanding individual.The combined mutation operator is used to take into account the global search ability and local search ability of the algorithm.In order to test the validity and computation efficiency of algorithm,selecting the four different test function was calculate b y the improved algorithm,the results show that compared with the traditional real-coded genetic algorithm,the improved real-coded genetic algorithm can avoid local convergence,reach the optimal,and the optimal speed faster,can find the optimal solution in the evolution of the less algebra.Four types of steering trapezoid mechanism are selected for exampl of optimal design,and the error between the theoretical angle and the actual angle of steering wheel before and after optimization is analyzed.The results show that the error ddecreases significantly,the effect of optimiize design was good.The method presented in this paper can guide the actual producction.