Servo - July 2011

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NOW

ROBOTS: FORM OR FUNCTION?

by Tom Carroll

There were some interesting comments on the various threads of the Seattle Robotics Society’s server in early April about what was more important: how a robot looked or how well it performed. Interestingly, both of these attributes are subject to personal preferences, especially the aesthetics of a particular robot. Most of us are quite content to build a robot that looks as good as we can make it, and have all of the physical and programmed functions work how we want them to work. At some point — as we scavenge or craft all of the parts of the robot that we can — we settle on the robot’s final appearance. The robot’s physical look is quite often either the result of a lot of time-consuming machining, carving, and polishing, or it is the outcome of what nice looking ‘things’ we can find to put on our creation. We can add circuits, sensors, motors, wheels, arms, claws, batteries, and even external lights that we buy or find somewhere within our stock of saved parts.

As far as function goes, we can test the many lines of code that we spent hours trying out on the bench, debugging, deleting, adding new code, and finally, loading it into our microcontroller. We can sit down with a CAD program and lay out the chassis and add the many motors, sensors, appendages, drive wheels, and external shell to approximate our final design. Most of the time, we have to measure the sizes of larger components such as motors, batteries, and drive systems that we have already located or purchased, and figure out where we need to place and mount them to have them function as we planned. Without going into complex differential equations, we can use finite element analysis programs to hone kinematics and the robot’s operations over different terrains to determine motor and gearbox sizes and configurations in the design process. Of course, robot design is certainly more complex than the few steps I just mentioned.

at a particular robot and feel that it is truly a work of art. They can view sleek lines, hidden motors, wires, and circuitry, and see a magnificent robot. Many builders have tried and succeeded to build a copy of the Johnny Five robot from the film, “Short Circuit,” shown in Figure 1. In that movie, there were no wires snaking up the arms of the robot and all of the articulated joints hid the internal components.

Many people have told me that they feel the Johnny Five robot was one of the most beautiful of all movie robots for that reason. Yes, it was a studio action prop, remotely-controlled by multiple special-effects operators on the sidelines, but the electronics and mechanics made Johnny Five one of the most complex action props ever used. These days, studios find it cheaper to construct computer-generated robots, such as the NS-5s from the Will Smith film, i-Robot — especially when the script called for a thousand robots as in Figure 2.

In a way, we can view function in the same light. People who have no idea just how hard it is to build a complex robot may laugh if they happen to see a bipedal humanoid take a few wobbly steps and then