Page 49 - Modern Control Systems

Section 1.6 Mechatronic Systems 23
these hybrid vehicles will never be zero-emission vehicles (since they have internal
combustion engines), they can reduce the level of harmful emissions by one-third to
one-half, and with future improvements, these emissions may reduce even further. As
slated earlier, the modern automobile requires many advanced control systems to
operate. The control systems must regulate the performance of the engine, including
fuel-air mixtures, valve timing, transmissions, wheel traction control, antilock brakes,
and electronically controlled suspensions, among many other functions. On the hy-
brid fuel vehicle, there are additional control functions that must be satisfied. Espe-
cially necessary is the control of power between the internal combustion engine and
the electric motor, determining power storage needs and implementing the battery
charging, and preparing the vehicle for low-emission start-ups. The overall effective-
ness of the hybrid fuel vehicle depends on the combination of power units that are
selected (e.g., battery versus fuel cell for power storage). Ultimately, however, the
control strategy that integrates the various electrical and mechanical components
into a viable transportation system strongly influences the acceptability of the hybrid
fuel vehicle concept in the marketplace. •

The second example of a mechatronic system is the advanced wind power gen-
eration system.

EXAMPLE 1.2 Wind power
Many nations in the world today are faced with unstable energy supplies, often leading
to rising fuel prices and energy shortages. Additionally, the negative effects of fossil fuel
utilization on the quality of our air are well documented. Many nations have an im-
balance in the supply and demand of energy, consuming more than they produce. To
address this imbalance, many engineers are considering developing advanced systems
to access other sources of energy, such as wind energy. In fact, wind energy is one of the
fastest-growing forms of energy generation in the United States and in other locations
around the world. A wind farm now in use in western Texas is illustrated in Figure 1.20.
In 2006. the installed global wind energy capacity was over 59,000 MW. In the
United States, there was enough energy derived from wind to power over 2.5 million
homes, according to the American Wind Energy Association. For the past 35 years,