Page 95 - Biosystems Engineering

76 Chapter Two

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10
9

8

Depth (cm) 7 6

4 5
3

2
1
0 5 10 15 20 25 30 35 40 45 50
Time (s)
FIGURE 2.23 Infl uence of a sinusoidal disturbance with amplitude of 5 cm
(solid) on the controlled response for the closed loop system with a
P-controller (dash) and with designed return ratio L(s) (dash-dot).
this example have not been explained in the theoretical part of this
chapter, it should be seen as a showcase demonstrating to the inter-
ested reader what is possible with biosystems analysis and optimiza-
tion rather than merely illustrating methods described here. We hope
this example teases you, as a reader, to start reading more advanced
books on the topic, like the ones cited throughout the text.
2.6.1 Motivation
Operator comfort is a hot topic in the world of farming machinery.
Operators work long days, and good operators are increasingly
hard to find. Ease of operation and operator comfort in general, are
therefore important aspects in the competition between different
manufacturers.
Environmental legislation is also becoming a more and more
important catalyst for machine automation. Recent legislation has
forced manufacturers to reduce the noise and the exhaust fumes of
their machines during road transport (European Commission 2004,
2005, 2006). Thus, it makes sense to reduce engine speed whenever
possible (i.e., in road conditions). A controller can now be designed to
control the pump setting and the engine speed of the diesel engine
such that the engine speed is minimized without losing acceleration
performance (Coen et al. 2008a, 2008b).