| 摘要 |
<p>The speed of a harvester is controlled by electrical signals derived from the functioning of the harvester. A first signal is obtained by sensing the density of some or all of the harvester output and a second signal is obtained from the drive for the harvesting apparatus. The first and second signals are compared to produce a difference signal with which the forward speed of the harvester is controlled so as to reduce the difference signal to a minimum. An indication of whether the actual speed of the harvester is correct or too slow or too fast at any instant, for a given crop loss is provided by three differently coloured lamps. The output from the straw shaker, the output from the sieve due to the air blast, and the output from the main sieve are sensed to provide output signals which are either treated separately or jointly to provide three individual signals or a composite signal relating to output density.</p> |
