Apparatus and method for controlling the speed of a combine harvester

A method of controlling the ground speed of a combine harvester including apparatus comprising:

• one or more sensors each generating one or more signals that correspond during use of the combine harvester to variables of a harvesting process;
• and
• a processor,
• the method further comprising the steps of generating in each of one or more sensors one or more signals that correspond during use of the combine harvester to variables of a harvesting process, and in dependence on the values of the signals operating at least two control devices connected in a feedback arrangement comprising two loops in a first loop of which a first signal corresponding to the ground speed of the combine harvester is fed back as an input to a first control device that is capable of adjusting the ground speed relative to a set value, and in a second loop of which the first signal is fed together with a second signal indicative of the flow rate of crop through the combine harvester to a second control device that generates as a third signal the set value, the third signal being input to the first control device.