基于人机工效学的农机座椅自动调平系统设计与试验

针对拖拉机在高低垄犁地作业过程，驾驶舱倾斜导致驾驶员坐姿变化，影响驾驶员乘坐舒适性的问题，设计了结构紧凑的座椅椅面调平机械装置，并基于单片机开发了调平装置控制器，调平精度为0.67°。为了提高调平过程中驾驶员的乘坐舒适性，搭建了模拟拖拉机座椅倾斜状态试验台，研究了试验台中座椅倾斜不同角度情况下对驾驶员上躯干姿态的影响。试验结果表明人体胸椎和腰椎投影偏移随着座椅倾斜角度的增加而增大，但座椅倾斜3°时投影偏移远小于倾斜5°时投影偏移，由此确定座椅调平系统工作阈值为3°。通过主观评价试验，确定座椅调平的速度为6～8 mm/s时，驾驶员的舒适性较高。在东方红LX754型拖拉机上开展实车试验，结果表明，座椅调平后驾驶员的腰部受力更加均匀、调平系统对于驾驶员的操作性及适应性有促进作用，验证了该系统的实用性。

Design and Test of Automatic Leveling System for Agricultural Machinery Seat Based on Ergonomics

Aiming at the problem that the driver''s sitting posture changes due to the cockpit tilt during the tractor ploughing operation on high and low ridges, which affects the driver''s ride comfort, a tractor seat leveling control system based on the driver''s comfort was designed, a seat leveling control strategy based on the driver''s ride comfort was proposed, and a seat leveling system controller was developed to feed back the seat tilt state in real time according to the seat angle sensor. The automatic leveling of the seat was realized. In order to better improve the driver''s riding comfort in the leveling process, a test-bed simulating the tilt state of tractor seat was built, and the influence of seat tilt on the driver''s upper torso posture under different angles in the test-bed was studied. The test results showed that the projection offset of human thoracic spine and lumbar spine was increased with the increase of seat tilt angle, but the projection offset when the seat was tilted at 3° was far less than that when the seat was tilted at 5°, which determined the operating threshold of the seat leveling system. Through the subjective evaluation test, it was determined that the driver''s comfort was higher when the speed of seat leveling was 6~8mm/s. Finally, the real vehicle test was carried out on Dongfanghong LX754 tractor. The comparison test of driver''s back muscle electromyography evaluation showed that the lumbar force was uniform compared with that without adjustment, which can well protect the driver''s lumbar muscle. The tractor operation accuracy test and the tractor straight-line driving path tracking test showed that the use of the seat leveling system improved the operation efficiency of the steering wheel and gear. After the seat leveling, the average error of operating the tractor straight-line was reduced by 3% and the maximum transverse error was reduced by 8%, which verified the practical value of the system. This research can improve the ride comfort of drivers.