Page 15 - Robotics Designing the Mechanisms for Automated Machinery

4 Introduction: Brief Historical Review and Main Definitions

2. A large body of technical skills and experience, and many innovations, were accu-
mulated by the craftsmen engaged in the production of such automatons. This amal-
gamation of knowledge, skills, and experience found application in the second line of
development mentioned above—development of, and the drive for perfection in,
industry.

We have reason to consider the clepsydra (a type of water clock) as the earliest rep-
resentative of robotic devices. Supposedly invented in 250 B.C., it was able to recycle
itself automatically. The centrifugal-speed governor for steam engines invented in 1788
by James Watt, together with the system of automatically controlled valves, made the
steam engine the first automatic device capable of keeping an almost constant rotat-
ing speed of the fly wheel regardless of changes in the load. Analogously, the internal
combustion engines invented in the nineteenth century serve as an example of another
automatically recycling device realizing repeatedly the suction, compression, and igni-
tion of the fuel mixture. The Industrial Revolution stimulated the creation of a number
of automatically operated machines first in the textile industry and later in machine
tools and other industrial operations. The most brilliant invention of this type was
Jacquard's loom, which had a punched-paper-tape-controlled system for flexible fabric-
pattern production. We will return to this example a number of times, but it is worth
mentioning here that this machine, which was introduced into industry as long ago
as 1801, was based on an idea which is applicable to almost every definition of a robot,
i.e., the machine is programmable and is intended for the execution of a variety of
fabric patterns.
In 1797, Henry Mandslay designed and built a screw-cutting lathe. The main feature
of this machine was that it had a lead screw for driving the carriage on which the cutter
was fastened and which was geared to the spindle of the lathe. Actually, this is a kind
of template or contour machining. By changing the gear ratio practically any thread
pitch could be obtained, i.e., the lead screw controlled a changeable program. Obvi-
ously, this is the precursor of the tracer techniques used widely in lathes and milling
machines. The later tools are to some extent robotic systems. The further refinement
of this machine tool led to the creation of automatic lathes of a purely mechanical
nature for the mass production of parts such as bolts, screws, nuts, and washers. These
machines were, and still are, mechanically programmed, and after two to three hours
the currently produced pattern can be exchanged for another. Many such machines
were first produced between the years 1920 and 1930.
In the 50s, after World War II, numerically controlled (NC) machine tools such as
lathes and milling machines were first introduced into industry. These machines were,
and still are, more flexible from the point of view of program changeability. At this level
of refinement, the relative positioning between the tool and the blank had to be made
by point-to-point programming of the displacements. When computerized numeri-
cally controlled (CNC) machines replaced NC machines, the programming became
more sophisticated—the trajectories were then computed by the computer of the
machine. At this level of refinement the operator had to define both the kind of the
trajectory (say, a straight line or an arc) and the actual parameters of the trajectory
(say, the coordinates of the points connecting the straight line or the center coordi-
nates and the radius of the arc, etc.). Other improvements were made in parallel, e.g.,
continuous measurement of the processed parts to fix the moment at which a tool