Page 39 - Robot Builders Source Book - Gordon McComb

28 Introduction: Brief Historical Review and Main Definitions

Analyzing Figure 1.28, we can offer the "waiter" several possible courses. For
example, from the bar or counter it can move through the following points:

1. A1-A2-A3-A4-B4-B3-B2-B1-C1-C2-C3-C4-D4-D3-D2-D1, or,
2. A1-A2-A3-A4-B4-C4-D4-D3-D2-D1-C1-B1-B2-B3-C3-C2-C1, etc.
The criteria we must satisfy here are:

• The minimal service time (which includes the distribution of meals, the col-
lection of dishes, the distribution of bills, and the collection of money);
• The optimal number of dishes on the trays;
• The minimal disturbance to the customers.

If the mobile robot is propelled on tracks, then a separate drive is required for navi-
gation of the tracks. If it is propelled by wheels, a steering wheel is required (3-wheel
designs are conventional), or each wheel is equipped with an independent drive of a
special kind (see Figure 9.55).
In the case of the above-described cafeteria, control could be effected, for instance,
by colored strips on the floor combined with a system capable of counting the number
of times the robot crosses each strip. The memory of the "waiter's" computer is pro-
grammed with the action it has to perform after each crossing point. The commands
would be of the kind:

• Go ahead;
• Stop;
• Turn left or right; or
• Turn around.
If such a vehicle were combined with a manipulator, we would obtain a very flexible
device which would be able to handle, for example, a suspicious object such as a bomb.

2. Exoskeletons

Let us imagine a person working in a "hostile environment," such as under water
or in space. His safety suit must withstand high pressures (external or internal). Obvi-
ously, the joints of such a suit, its weight, and its resistance to the environment will
hamper the movement of the person. Thus, special means must be provided to com-
pensate for these harmful forces. These means can comprise an external energy source
linked to a type of amplifier which permits the person enclosed in the safety suit to
act almost normally as a result of the fact that the real forces developed by the device
are significantly larger than those developed by the working person. We can then
"extrapolate" the situation of the hostile environment to normal circumstances to
provide a person with a means of protection from the environment or with a means
of handling heavy objects which are far beyond the limits of a normal person. What-
ever the specific application of use of the device, it must: 1) free the skeleton of the
person from physical overloads; 2) amplify the person's muscular efforts; and 3) provide
feedback to enable the user to gauge the reaction of the object being manipulated.
The first requirement described above indicates that the device has an auxiliary
function to the human skeleton, hence the name, exoskeleton. One possible design
comprises a double-layered structure. The internal layer, which includes the control
mechanism, makes direct contact with the operator. The external cover follows the
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