Intelligent Robots: Development and Teaching Methods | Machines | Engineering

Intelligent robots are third generation robots, broadly termed as adaptive and communicating robots. intelligent robots equipped with one or more advanced external sensors, interfaced with other machines, and communicating with other computers.

Interfaced with machine vision, proximity and other sensor systems (i.e. tactile, force, torque) the robot can acquire randomly positioned and oriented work pieces, inspect them for gross defects, transport them to assigned position in relation to other work pieces, do insertions or other mating functions; performing fastening operations, and finally verify acceptable completion of these intermediate assembly process.

The major functional elements of an intelligent robot system are:

(a) The capability of a robot system to adapt to its immediate environment by sensing changes or differences from some pre-specified standard conditions and by computing, in real time, the necessary corrections for trajectories and/or manipulative actions.

(b) The capability of interacting and communicating with associated devices and with other computers so that smoothly integrated manufacturing system can be implemented, incorporating fail safe procedures and alternate courses of actions to maintain production continuity.

Development of Intelligent Robots:

Industrial robots have been steadily developing as key components in factory automation. Recent trends indicate an increasing need to improve the engineering of certain aspects of robotics including teaching (the robot), adaptability to a system (including expansion of the system), and a robot support system.

The uses of industrial robots have expanded from the initial duties of material handling, spot welding, arc welding and painting to assembling, sealing, deburring and inspection. In addition to the use of robots in manufacturing industries as a high-performance terminal device for factory automation, various robots are used in non-manufacturing industries, like inspection robot in nuclear power industry and service robots in tertiary industries.

At present the emphasis of robot developing is shifting from hardware to software. More efforts are being made to make the robot user-friendly and to expand its application.

Majority of intelligent robot presently available are vertical and horizontal-articulated type robots. Robots like the Cartesian coordinates type, the cylindrical coordinates type and the polar coordinates are also available but in small number. The latest design of intelligent robot are the pendulum type and spinal type (elephant nose type).

Attempts are now on to develop multi-freedom type robot with a redundancy of six or more axes, thus it will be a robot combined with traveling units of various types. Attempts are also in the direction of weight reduction, by adopting new structural materials and rational structure designing techniques.

Operation speed of 5 m/s has been attained with DC and AC servo motors, and speed also increased for a short time to 10 m/s through the use of a direct drive motor. On an industrial robot with a limited range of motion, acceleration greatly influences the cycle time. Rigidity is the basic factor in achieving high speed and high precision.

The software servo system has initiated a trend to adopt total digital servo system in order to increase precision. New control logics are being applied to improve response and path accuracy. Programmable controllers enable improve operability and expandability. The higher performance and increased functions make robots less easy to operate and maintain the teaching process more complicated and time-consuming.

Teaching Methods of Intelligent Robots:

Various teaching methods of intelligent robot are:

(i) Direct Teaching:

Since a robot can be led directly to the necessary position and posture, the direct teaching method is simpler. Operation by way of a joy stick handle attached to the operation panel is the easiest method, after direct teaching has been initiated.

(ii) Expert System Based on Artificial Intelligence Technology:

With this system, details of the work know how is stored into an intelligent data base in advance. The operator inputs basic common conditions such as, in the case of arc welding, the material type, thickness, etc. If the welding path is input, then all work conditions are determined based on the basic common conditions such as, in the case of arc welding, the material type, thickness, etc.

If the welding path is input, then all work conditions are determined based on the basic conditions stored in the intelligent data base. The teaching data is automatically created on an expert level (level of the intelligent data base). If an expert tries to improve the quality of the intelligent data base, users of the data base can work at the expert level.

(iii) Off-Line Teaching:

In this method, the teaching data for other robots is used, numerical values and commands are entered from the keyboard, or graphics are entered in conversation form with the CRT screen. In all cases, data for work conditions, which is associated with its knowhow, must be entered in the same manner as in the expert system.

(iv) “Computer Aided Design/Computer Aided Manufacturing” (CAD/CAM) System:

In this system the intelligent robot work data is prepared from CAD data from the first designing process. This system is a kind of off-line teaching system. Since an actual robot is not used to input data for path creation, the coordinates system data must be corrected and simulation is necessary before loading the created data.

intelligent robot are inevitable for application in fields where the work is extremely difficult or impossible for human beings to perform.

Some of such examples are:

Work requiring speed, precision or function exceeding human ability, or that which requires entering a sterile environment, vacuum, outer space, the sea floor or around a nuclear reactor, places that a man cannot enter easily or at all.

Assembly in the optical industry, needs high precision which is extremely difficult for humans to perform. Electronic parts are manufactured in a sterile room where only robots can work as humans are considered to be source of dust.