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Bell High engineering students build robot

Automation is everywhere today.  Seems you can’t go anywhere or do anything these days without automation being right there by your side.  Automation makes our lives as humans much easier and is usually employed in the tireless, thankless, repetitive type jobs that many of us are not interested in doing.  That takes us to the story of the Bell High School Engineering Academy students and Coach Mehl’s need for a clean gym floor.  Coach Mehl’s basketball team often times had to clean the gym floor before, during and after each game due to the debris that accumulated on the floor.  This was typically accomplished by one or more of the basketball players manually dragging a large sweeping type boom around the gym floor to remove any debris and or moisture from the floor.  This provided for a better, safer basketball court for each of the games.

One afternoon while speaking to Mr. Barselou, Trenton and Bell High School Engineering Academy instructor, Coach Mehl asked if there was a better way to get this job done.  Mr. Barselou brought coach Mehl’s question to us at BHS Engineering Academy.  We discussed and researched what options were currently available and determined that the best course of action was to simply design and build a robot to accomplish this task.

Our engineering class had to come up with a design that worked with the specifications that Coach Mehl wanted.  We brainstormed a multitude of ideas while searching online for parts, off the shelf as they are called, that we thought would work the best for the robot and be cost effective.  Through the use of Solidworks, our 3D computer modeling software that we use in engineering, we designed a 30” wide x 40” long tubular steel frame. The robot had to be big enough to hold the weight of an 8’ sweeper beam, but also small enough to fit through a doorway so Coach Mehl could “pilot” it into his storage room and park it out of the way when he was done with it.  The frame housed two DC powered step-down (gear reduction) motors which provide power to the left and right mid-frame mounted traction wheels.  The entire system was designed to be remotely operated, much like any remote controlled car, truck or plane.  Once the preliminary design was done and parts were ordered we had to start the building process.

To build the robot we all had to learn basic metal fabrication skills and learn to weld. With that knowledge we had to fabricate the frame, or main body of the robot.  Once the frame was put together, it was time to install the controls.  This required each of us to learn basic electrical circuitry and electrical skills to install the 12 volt DC battery, wiring harnesses and 15 amp dual brushed motor controllers.  The dual DC brushed motor drives the system with very high torque, and low speed, to pull the sweeper beam.  The motors turn large pneumatic wheels that grip the floor but don’t scratch the surface, all while being balanced by single swivel wheels located in the front and back of the machine.

As with any engineering project, once we put it all together we had some complications.  First the drive motor shafts failed.  Every attempt we made to rectify the shortfall failed.  Once it was decided to weld the drive shaft versus employing locking pins or bolts we finally were able to resolve that issue. But just as we solved that problem the dual motor speed control got overloaded and burned up.  This forced us to redesign the control and drive system yet again to employ a larger, more powerful, 60 amp speed control.  Just when we thought it was all good and ready to go we found out that the large pneumatic tires were breaking traction with the floor and spinning freely whenever the robot hit a patch of cleaning solution on the floor. As a result it was back to the drawing board for all of us once again.  Thankfully, while brain-storming possible solutions we were able to design and construct a low cost, highly effective water removal system in front of each of the drive wheels to keep them from breaking traction with the gym floor.

The robot is designed to travel three to six miles per hour, via remote control, and run for approximately 1-1/2 hours on a single charge.  To date, the robot cost the Engineering Academy approximately $500 to design and construct but the learning and knowledge we’ve gained from the process is invaluable.  The project team leader was Zac McPhearson, a junior at BHS.  Team members include;  Reese Rankin and Sara O’Sullivan who completed most of the steel fabrications, Dale Douglas who did the welding and electrical work,  Molly O’Sullivan prepped, primed, painted and installed the robots LED lighting and Emily Skawienski who’s primary responsibility was design and research.

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