Page 80 - The Mechatronics Handbook

6.4 Design of Mechatronic Systems

One of the most challenging problems in mechatronic systems design is the system architecture synthesis,
system integration, optimization, as well as selection of hardware (actuators, sensors, power electronics,
ICs, microcontrollers, and DSPs) and software (environments, tools, computation algorithms to perform
control, sensing, execution, emulation, information flow, data acquisition, simulation, visualization,
virtual prototyping, and evaluation). Attempts to design state-of-the-art high-performance mechatronic
systems and to guarantee the integrated design can be pursued through analysis of complex patterns and
paradigms of evolutionary developed biological systems. Recent trends in engineering have increased the
emphasis on integrated analysis, design, and control of advanced electromechanical systems. The scope
of mechatronic systems has continued to expand, and, in addition to actuators, sensors, power electronics,
ICs, antennas, microprocessors, DSPs, as well as input/output devices, many other subsystems must be
integrated. The design process is evolutionary in nature. It starts with a given set of requirements and
specifications. High-level functional design is performed first in order to produce detailed design at the
subsystem and component level. Using the advanced subsystems and components, the initial design is
performed, and the closed-loop electromechanical system performance is tested against the requirements.
If requirements and specifications are not met, the designer revises or refines the system architecture,
and other solutions are sought. At each level of the design hierarchy, the system performance in the
behavioral domain is used to evaluate and refine the design process and solution devised. Each level of
the design hierarchy corresponds to a particular abstraction level and has the specified set of activities
and design tools that support the design at this level. For example, different criteria are used to design
actuators and ICs due to different behavior, physical properties, operational principles, and performance
criteria imposed for these components. It should be emphasized that the level of hierarchy must be defined,
e.g., there is no need to study the behavior of millions of transistors on each IC chip because mechatronic
systems integrate hundreds of ICs, and the end-to-end behavior of ICs is usually evaluated (ICs are
assumed to be optimized, and these ICs are used as ready-to-use components). The design flow is
illustrated in Fig. 6.3.
Automated synthesis can be attained to implement this design flow. The design of mechatronic
systems is a process that starts from the specification of requirements and progressively proceeds to
perform a functional design and optimization that is gradually refined through a sequence of steps.
Specifications typically include the performance requirements derived from systems functionality,
operating envelope, affordability, and other requirements. Both top-down and bottom-up approaches
should be combined to design high-performance mechatronic systems augmenting hierarchy, integ-
rity, regularity, modularity, compliance, and completeness in the synthesis process. Even though the

Achieved System Desired System
Performance: Performance:
Behavioral Domain Behavioral Domain
System
Design,
Synthesis, and
Optimization
System Synthesis in
Structural/Architectural
Domain

FIGURE 6.3 Design flow in synthesis of mechatronic systems.

©2002 CRC Press LLC