7. MILLILITERS COLLECTED = LITERS PER HECTARE BEING APPLIED
1.6.4. Information and Control Systems
Information and control systems are used on combines to: increase productivity, decrease harvest costs, improve harvest quality, reduce operator stress acquire crop yield and moisture data, and improve harvest management.
Cabs and Controls (Operator Compartment)
Dust proof and sometimes air-conditioned cabs, along with well-arranged, easily reached operating controls make work easier for the operator. If these are provided, the operator can concentrate more on the harvest process and optimize combine capacity. By integrating essential electrically operated functions in a multifunction lever or joy stick control it is possible to adjust the reel and the cutterbar by touch (Fig. 1.294). The work of the operator in changing fields or crops is simplified by systems to adjust the threshing and separating elements. Adjustment settings of several elements according to different crop and harvest conditions are saved in a microprocessor. When required, the threshing and separating elements are set to the stored values in memory by electro-hydraulic controllers. The stored values can be upgraded by operator experience.
Information Systems
Information systems contain supervision and warning devices, decision help for ad- justment of the combine, and the registration of management data. Supervision and warn- ing devices inform the operator about such factors as: the technical condition of the engine (temperature, oil pressure etc.); the rotational speed of the most important shafts; level of grain in the grain tank; tendency for straw walker blockage and grain loss indication.
Grain loss sensors are an essential guide to combine forward speed and therefore the throughput set according to the loss throughput curve. The loss sensors register grain that has bypassed cleaning unit or straw walkers and falls onto the sensors. Grain impacts are converted into impulse signals by a microphone, and the frequency of the impulses
Figure 1.294. Speed control levers with integrated
switches.
Figure 1.295. Sensors for measuring grain throughput.
is indicated to the operator on the grain loss monitors, which accordingly are providing relative loss values, not absolute loss level.
Area capacity, grain throughput and amount of grain harvested per day or per field are important management data. Recording the grain throughput is also necessary for yield mapping. Measuring MOG throughput is important for the forward speed control.
Measuring grain flow is carried out with different sensors (Fig. 1.295). Grain-volume flow devices (paddle wheel, light barriers in the clean grain elevator) are commercially available which require the input of the actual density of the grain for calibration; in addition grain throughput is measured by gamma radiation or capacity changes of the electrical field. The information is indicated on a screen (AgroCom, Claas; Field Star, MF; Green Star, John Deere). With the aid of satellite GPS, field-yield can also be plotted from stored data.
Although volume and torque measuring devices have been examined for determining MOG throughput, the signals are influenced by idle torque and actual crop density. There was only one MOG measuring system in production in 1997 (belt slip of threshing cylinder drive, MF).
Control Systems
Control systems relieve the operator from the need to precisely track the adjustment parameters according to the actual harvest conditions. Important control systems can manage:
• Cutter bar position and platform height
• Leveling of hill combines or cleaning shoes
• Automatic steering down the row for corn harvesters (Fig. 1.296)
One type of sensor for position control of the cutterbar uses two end-mounted height sen- sors, although there may be problems driving backwards. Contactless working ultrasonic sensors for height control are also available.
Figure 1.296. Sensor bars for automatic steering of corn harvesters.
Automatic steering needs stringent safety requirements. Automatic steering in corn rows reduces strain on the operator. Working in the evening in the twilight is possible.
Operating speed with automatic steering is about 10% higher than without.
Automatic adjustment of forward speed dependent on the throughput of MOG and on the losses according to the loss/throughput curve had not been completely solved by 1997. The investigations by Eimer in 1973 [19] have shown fundamental advantages.
Huisman and McGechan [20, 21] judge the economic advantages critically. Measuring the MOG throughput inside the combine, however, is subject to the fundamental fault that the measurement is carried out too late, so keeping the throughput at a constant value is difficult to achieve. Recording crop density in front of the combine is important in order to adjust a constant throughput by changing forward speed. Yield mapping, which analyzes previously harvested rows, allows estimates of crop densities in front of the combine [22].