Page 58 - The Mechatronics Handbook

FIGURE 4.3 Example of a small mechatronic system: The ALAMBETA device for measurement of thermal prop-
erties of fabrics and plastic foils (manufactured by SENSORA, Czech Republic). It employs a unique measuring
method using extra thin heat flow sensors, sample thickness measurement incorporated into a head drive, micro-
processor control, and connection with a PC.

1981, multi-boxes (desktop or tower case, monitor, keyboard, mouse) or single-box (notebook) micro-
computers became a daily-used personal tool for word processing, spreadsheet calculation, game playing,
drawing, multimedia processing, and presentations. When connected in a local area network (LAN) or
over the Internet, these “personal computers (PCs)” are able to exchange data and to browse the World
Wide Web (WWW).
Besides these “visible” computers, many embedded microcomputers are hidden in products such as
machines, vehicles, measuring instruments, telecommunication devices, home appliances, consumer
electronic products (cameras, hi-fi systems, televisions, video recorders, mobile phones, music instru-
ments, toys, air-conditioning). They are connected with sensors, user interfaces (buttons and displays),
and actuators. Programmability of such controllers brings flexibility to the devices (function program
choice), some kind of intelligence (fuzzy logic), and user-friendly action. It ensures higher reliability and
easier maintenance, repairs, (auto)calibration, (auto)diagnostics, and introduces the possibility of their
interconnection—mutual communication or hierarchical control in a whole plant or in a smart house.
A photograph of an electrically operated instrument is given in Fig. 4.3.
Embedded microcomputers are based on the Harvard architecture where code and data memories are
split. Firmware (program code) is cross-compiled on a development system and then resides in a non-
volatile memory. In this way, a single main program can run immediately after a supply is switched on.
Relatively expensive and shock sensitive mechanical memory devices (hard disks) and vacuum tube
monitors have been replaced with memory cards or solid state disks (if an archive memory is essential)
and LED segment displays or LCDs. A PC-like keyboard can be replaced by a device/function specifically
labeled key set and/or common keys (arrows, Enter, Escape) completed with numeric keys, if necessary.
Such key sets, auxiliary switches, large buttons, the main switch, and display can be located in water and
dust resistant operator panels.
Progress in circuit integration caused fast development of microcontrollers in the last two decades.
Code memory, data memory, clock generator, and a diverse set of peripheral circuits are integrated with
the CPU (Fig. 4.4) to insert such complete single-chip microcomputers into an application specific PCB.
Digital signal processors (DSPs) are specialized embedded microprocessors with some on-chip periph-
erals but with external ADC/DAC, which represent the most important input/output channel. DSPs have
a parallel computing architecture and a fixed point or floating point instruction set optimized for typical
signal processing operations such as discrete transformations, filtering, convolution, and coding. We can
find DSPs in applications like sound processing/generation, sensor (e.g., vibration) signal analysis,

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