关键词: 拖拉机, 制动性能, 气压制动, 改进粒子群算法

Abstract: In order to further improve the safety of pneumatic braking system under complex road surface, the braking performance of agricultural fourwheel tractor was studied. Aiming at the shortage of convergence speed and accuracy of standard particle swarm optimization (PSO), an improved particle swarm optimization (IPSO) algorithm was proposed. The results of four test functions of the two algorithms showed that IPSO had faster convergence speed and higher accuracy. Through the test and system identification method, the pneumatic braking system model was identified, and based on this, a simulation model of ABS braking performance of agricultural fourwheel tractor with pneumatic braking system was built considering the drivers operation behavior, so as to restore the real braking process. The braking performance of IPSO-PID control algorithm under special road surface was simulated and analyzed. The results showed that the braking distance and braking time of ABS controlled by IPSO-PID were 15.12 m and 219 s, respectively, which were 8.25% and 10.61% shorter than those without control. In the case of staggered road braking, the braking distance and braking time of ABS controlled by IPSO-PID were 15.47 m and 2.29 s, which were 781% and 10.55% shorter than those without control, respectively. 

Key words: tractor, braking performance, pneumatic brake, improved particle swarm optimization algorithm