Adaptive Control System
Published on Aug 15, 2016
From In an ideal scenario of intelligent machine tools the human mechanist was almost replaced by the controller. During the last decade many efforts have been made to get closer to this ideal scenario, but the way of information processing within the CNC did not change too much.
The paper summarizes the requirements of an intelligent CNC evaluating the advancement of technology in this field using different adaptive control systems. In this paper a low cost concept for artificial intelligence named Knowledge Server for Controllers (KSC) is introduced. It allows more devices to solve their intelligent processing needs using the same server that is capable to process intelligent data. The KSC concept is used in an open CNC environment to build up an intelligent CNC.
RESULTS IN INTELLIGENT CNC s:
On the one hand in the recent literature one can find many different topics related to intelligent CNCs. Unfortunately they often do not mean intelligent behaviors but the application of intelligent methods. Sometimes it is the case that authors call their devices "intelligent" if one module of the system contains based method. On the other hand (2) the key controller vendors leave everything to the users or machine tool builders offering PC/Windows based CNCs. With these systems any software modules (e.g. even adaptive control based ones) can be coupled into the controller but they do not offer J real solutions or methodologies, but only software possibilities.
The following list summarizes the most important active research topics in this field. A real intelligent CNC would contain most of these issues.
1) Fuzzy logic based concurrent control of some operating parameters
(E.g. cutting speed, depth of cut, feed rate) independently from the
Given tool and the work piece.
2) Neural nets and fuzzy rules in the CNC's control algorithms.
3) Optimal path planning, real-time correction of the trajectory.
4). Compensation of temperature (and other) deformations.
5) Life time management of the tools and other parts of the machine tool including self-diagnostics.
6) Tool breakage detection (maybe forecasting) and tool wear Monitoring (maybe compensation) with AI methods.
7) The utilization of CNC management (setup, orders, etc.) via Intelligent agents.
Intelligent parts of a CNC can be classified into three groups, namely:
(1) Tool monitoring,
(2) operation/machine tool modeling and
(3) Adaptive control.
A general problem in all the three groups is that the adaptive control based solutions are typically limited and valid only in a very narrow field. If one changes some parameters of the operation or the environment, the earlier successful methods become false
Adaptive Control System :
In adaptive control, the operating parameters automatically adapt themselves to conform to new circumstances such as changes in the dynamics of the particular process and any arise.
The adaptive would check load conditions, adapt an appropriate desired braking profile (for ex: antilock brake system and traction control), and then use feed back to implement it. With advanced adaptive controllers the gain may vary continuously with changes in operating condition.
Purpose of adaptive control:
• to optimize production rate
• to optimize product cost
to minimize cost