الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Combines and reapers harvest the grain crops, the green grass and other similar plants therefore, the cutter bar should be able to cut from 50 to 100 mm above the ground surface. The cutting parts should also be protected from hitting the rocks or the soil.
It should also be considered that any crop remains of cutting height on the ground after the harvest are losses.
The muddy conditions found in rice growing area proved difficulty, because the cutter could hit the ground when the combine header would sink into the soil. Running the stubble cutter into the soil would cause it to jam or partially plug up, making it ineffective.
Combines, in Egypt, face another big problem which hinders its movement on the agricultural land during the harvest. This problem is the jutting parts of the covered drainage rooms which are covered by plants and invisible to the combine operator. As a result, the combine crashes on these rooms causing great damage to it.
The main purpose of this study was to cut the crop at the lowest possible level by designing and manufacturing automatic control unit which controls upping/downing the combine header, in order to avoid the obstacles which face it when lowering the cutter bar level. On the other hand, designing and manufacturing another automatic control unit that stops the combine to protect the combine header from crashing on the high obstacles such as the jutting parts of the covered drainage rooms that spread over the agricultural land in Egypt.
Both automatic control units have been constructed locally at the engineering workshop of Rice Mechanization Center (R.M.C), Meet El-Deeba, Kafrelsheikh Governorate, Egypt during the year of 2006.
The experiments were carried out during rice harvest season of 2007 in order to compare two combine systems for the combine (Yanmar-CA65V) under the same different operating conditions. The first combine has two automatic control units (combine with control system). But the second combine doesn’t have two automatic control units (combine without control system or the conventional combine). All experiments performed at the research farm of Rice Mechanization Center.
The obtained results may be summarized as follows:
1- The combine with control system gave a good performance at forward speed of 2.5 km/h and cutting height of 0.05 m.
2- The conventional combine gave a good performance at forward speed of 2.5 km/h and cutting height of 0.10 m.
3- The combine with control system is strongly recommended since it gives lower loss and costs, and higher field efficiency compared to the conventional combine.