薯类收获机挖掘深度自动控制系统设计与试验

为了提升薯类收获机械自动化水平，提高明薯率，降低伤薯率和漏挖率，减小挖掘阻力，根据垄作薯类作物种植模式，以牵引式薯类收获机为载体，采用传感器和微处理器控制技术，设计了一种挖掘深度自动控制系统。该系统包括前仿形装置、挖掘机构、液压装置和控制系统。以垄沟地面为研究对象，采用接触式深度探测机构，其仿形深度和宽度可调节，挖掘深度实时调整可有效实现减阻降耗。建立挖掘深度调节模型，设计双阈值死区控制算法，实现系统精确稳定控制，有效避免控制信号频繁跳变和超调，提高薯类作物收获性能指标。田间试验表明，具有挖掘深度自动控制功能的薯类收获机其明薯率为97.37%，伤薯率为1.49%，漏挖率为1.59%。相比采用人工收获，其明薯率提升了2.20个百分点，伤薯率降低了1.41个百分点，漏挖率降低了2.00个百分点。

Development of Automatic Depth Control System Employed in Potato Harvester

In order to improve the automation level of potato harvesting machinery, improve the potato obvious rate and reduce the injury rate and undug rate, with the traction-type potato harvester as the carrier, an automatic depth control system designed. Sensor and microprocessor control technology was used. The system included the front profiling device, the digging mechanism, the hydraulic device and the control system. Using the excavation depth real-time adjustment algorithm, the excavation depth adjustment model was established, and the precise control of the harvester excavation depth was effectively realized, and the harvest performance index of potato crops was improved. Finally, test was carried out to verify the effectiveness of the automatic depth control system. According to the growth depth of sweet potato, the initial excavation depth was 260 mm. The machine harvested six ridges with automatic depth control device and six ridges without the device. Harvest trials were performed interlaced and a total of 12 ridges were harvested for comparative test, and the harvest speed was 1.4~1.6m/s. The test results showed that with manual depth control the average potato obvious rate was 95.17%, the average injury rate was 2.90% and the average undug rate was 3.59%. With the automatic depth control the average potato obvious rate was 97.37%, the average injury rate was 1.49%, and the average undug rate was 1.59%. Through comparison, it can be seen that after the use of automatic depth control device in the harvest process, the average potato obvious rate was increased by 2.20 percentage points, the average injury rate was decreased by 1.41 percentage points, and the average undug rate was decreased by 2.00 percentage points. Harvest performance indicators exceeded the qualified value requirements. It can be seen that after the 4UGS2 double row potato harvester was installed with the automatic deep control device, it can change the excavation depth according to the change of the bottom of the ridge. The harvester can improve its operation performance index, reduce the loss in the harvest process, and thus increase the economic benefits.