Page 31 - The Mechatronics Handbook

TABLE 2.2 Properties of Conventional and Mechatronic Design Systems
Conventional Design Mechatronic Design
Added components Integration of components (hardware)
1 Bulky Compact
2 Complex mechanisms Simple mechanisms
3 Cable problems Bus or wireless communication
4 Connected components Autonomous units
Simple control Integration by information processing (software)
5 Stiff construction Elastic construction with damping by electronic feedback
6 Feedforward control, linear (analog) control Programmable feedback (nonlinear) digital control
7 Precision through narrow tolerances Precision through measurement and feedback control
8 Nonmeasurable quantities change arbitrarily Control of nonmeasurable estimated quantities
9 Simple monitoring Supervision with fault diagnosis
10 Fixed abilities Learning abilities

FIGURE 2.3 General scheme of a (classical) mechanical-electronic system.

2.3 Ways of Integration

Figure 2.3 shows a general scheme of a classical mechanical-electronic system. Such systems resulted from
adding available sensors, actuators, and analog or digital controllers to mechanical components. The limits
of this approach were given by the lack of suitable sensors and actuators, the unsatisfactory life time
under rough operating conditions (acceleration, temperature, contamination), the large space require-
ments, the required cables, and relatively slow data processing. With increasing improvements in minia-
turization, robustness, and computing power of microelectronic components, one can now put more
emphasis on electronics in the design of a mechatronic system. More autonomous systems can be envisioned,
such as capsuled units with touchless signal transfer or bus connections, and robust microelectronics.
The integration within a mechatronic system can be performed through the integration of components
and through the integration of information processing.

Integration of Components (Hardware)
The integration of components (hardware integration) results from designing the mechatronic system
as an overall system and imbedding the sensors, actuators, and microcomputers into the mechanical
process, as seen in Fig. 2.4. This spatial integration may be limited to the process and sensor, or to the
process and actuator. Microcomputers can be integrated with the actuator, the process or sensor, or can
be arranged at several places.
Integrated sensors and microcomputers lead to smart sensors, and integrated actuators and microcom-
puters lead to smart actuators. For larger systems, bus connections will replace cables. Hence, there are
several possibilities to build up an integrated overall system by proper integration of the hardware.

Integration of Information Processing (Software)
The integration of information processing (software integration) is mostly based on advanced control

functions. Besides a basic feedforward and feedback control, an additional influence may take place
through the process knowledge and corresponding online information processing, as seen in Fig. 2.4.
This means a processing of available signals at higher levels, including the solution of tasks like supervision

©2002 CRC Press LLC