Principles of construction of mechatronic systems

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Figure 1.2 – Generalized scheme of the machine with a computer-controlled traffic
Examples of such influences are cutting forces for machining operations, 
contact forces and moments of forces during assembly, reaction force of a 
liquid jet during a hydraulic cutting operation. External environments can be 
broadly divided into two main classes: deterministic and nondeterministic. 
Deterministic include environments for which parameters of perturbing 
influences and characteristics of objects of work can be predetermined with 
the degree of accuracy necessary for designing the MS. Some environments 
are nondeterministic in nature (e.g., extreme environment: underwater, under-
ground, etc.). 
The characteristics of technological media can generally be determined 
using analytical and experimental studies and computer modeling techniques.
For example, to evaluate the cutting forces during machining, a series of 
experiments are carried out on special research installations, the parameters 
of vibration effects are measured on vibration tables with the subsequent 
formation of mathematical and computer models of perturbing effects on the 
basis of experimental data. However, the organization and conduct of such 

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studies require too complicated and expensive equipment and measurement 
technologies.
So for the preliminary assessment of the force effects on the operating body 
during the operation of robotic removal of the oblong from cast products, it is 
necessary to measure the actual shape and dimensions of each workpiece. 
In such cases it is expedient to apply methods of adaptive management, 
which allow you automatically to adjust the law of motion of the MS directly in 
the progress of the operation.
The structure of the traditional machine includes the following main 
components: a mechanical device, the final link of which is the working element; 
a drive unit including power converters and actuators; a computer control 
device, the upper level for which is the human operator, or another computer 
entering the computer network; sensors designed to transmit information to the 
control device on the actual state of the machine blocks and the movement of 
the MS.
Thus, the presence of three compulsory parts – mechanical (or rather electro-
mechanical), electronic and computer associated with energy and information 
flows, is the primary feature that distinguishes mechatronic systems.
The electromechanical part includes mechanical links and transmissions, 
working element, electric motors, sensors and additional electrical elements 
(brakes, couplings). The mechanical device is designed to transform the move-
ments of the links into the required movement of the working body. 
The electronic part consists of microelectronic devices, power converters 
and electronics of measuring circuits. The sensors are designed to collect 
data on the actual state of the external environment and objects of work, 
the mechanical device and the drive unit, followed by initial processing and 
transfer of this information to the computer control device (CCD). The CCD of 
a mechatronic system usually includes a computer and motion controllers. The 
computer control device performs the following main functions:
I. Controlling the process of mechanical motion of a mechatronic module 
or a multidimensional system in real time with the processing of sensory 
information.
II. The organization of management of functional movements of the 
MS, which involves the coordination of the control of the mechanical 
movement of the MS and the accompanying external processes. As 
a rule, discrete inputs/outputs of the device are used to implement the 
function of controlling external processes.
III. Interaction with the human operator through the human-machine 
interface in (off-line) and direct-motion modes of the MS in (on-line).

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IV. Organization of data exchange with peripheral devices, sensors and 
other devices of the system. The task of the mechatronic system is the 
transformation of the input information coming from the upper control 
level into a targeted mechanical movement with control based on the 
feedback principle. It is characteristic that electric energy (less often 
hydraulic or pneumatic) is used in modern systems as an intermediate 
energy form. 
The essence of the mechatronic approach to design [2] consists in integrating 
into a single functional module two or more elements of possibly even different 
physical nature. In other words, at the design stage, the traditional structure 
of the machine excludes at least one interface as a separate device, while 
preserving the physical transformation entity performed by this module. In an 
ideal variant for the user, the mechatronic module, having received information 
on the control purpose, will perform the specified functional movement with 
the desired quality indicators.
The hardware integration of elements into single design modules must 
necessarily be accompanied by the development of integrated software.
The MS software should provide a direct transition from the design of the 
system through its mathematical modeling to real-time control of functional 
motion. The use of the mechatronic approach in the creation of computers with 
computer control determines their main advantages in comparison with the 
traditional means of automation:
• relatively low cost due to the high degree of integration, unification and 
standardization of all elements and interfaces; 
• high quality of realization of complex and precise movements due to 
application of methods of intellectual control; 
• high reliability, durability and noise immunity; 
• constructive compactness of modules (up to miniaturization in 
micromachines);
• Improved weight and size characteristics of machines due to simplification 
of kinematic chains;
• the ability to integrate functional modules into complex systems and 
complexes for specific customer tasks.

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