农用底盘轮距可调式转向机构

Design of Steering Mechanism with Adjustable Wheel Track

摘要:

针对农用底盘轮距随农作物行距变化而适应性调整的技术需求，基于现有梯形转向机构、平行四边形机构，研究轮距调整联动转向原理，提出轮距调整和转向独立或同时进行的轮距可调式转向机构方案，确定关键参数和转向误差计算方法。设计了一种轮距可调式农用底盘，参照现有底盘相关参数并结合我国部分农作物行距分布情况，确定前桥轮距可调式转向机构关键参数并以最小轮距为基本轮距优化，分析不同轮距时的转向误差，计算结果表明：轮距调整后转向误差仍能满足农田作业转向要求。

Abstract:

The mechanical work such as weeding, spraying and fertilization requires the chassis should move along the crops’ row spacing. Since the row spacing of different crops is various and the row spacing of the same crop in different regions or by different planted methods are also not uniform, there are some problems such as poor flexibility, difficult passing ability, and tendency to destroy the crops when the existing agricultural vehicles running. So the agricultural chassis’ wheel track should be adjustable basing on the different crop spacings, during which the steering must be difficult. At present, steering has been solved by hydraulic drive, servo control the turning wheel, or servo motor control the turning wheel, which are more complicated. According to the demand for the chassis’ adjustable wheel track varying with different row spacings, the linkage principle of wheel track and steering was researched. Based on the Ackerman steering and parallelogram mechanism，the steering mechanism with adjustable wheel track was proposed in which the wheel track adjustment and steering can be completed independently and simultaneously, and the calculation method of key parameters and steering error were ascertained. A kind of agricultural chassis with adjustable wheel track was designed which included steering mechanism with adjustable wheel track on front bridge, adjustable wheel track mechanism and driving system on rear bridge. Basing on the characteristic of mechanism movement and the criterion of mechanical design, considering the present related chassis and the crop planting mode of China, the key parameters of the chassis has been determined. And the key parameters of steering mechanism with adjustable wheel track on front bridge were determined and optimized by taking minimum wheel track as basic wheel track. The steering error calculation results in different wheel tracks showed that the chassis’adjustable wheel track and steering performance could meet the agricultural needs.