tir38

After assembling the hardware for my SLAM (Simultaneous Localization and Mapping) robot, I set about to write the code which controls the drive motors, senses obstacles, and records the robot’s path. Lego’s NXT kit comes with a rather basic visual programming language called NXT-G. This program, which constructs programs by creating essentially flow charts, is almost counterintuitive to anyone with command line programing experience. I decided instead to use the third-party programming language called Not eXactly C (NXC) and its associated IDE, Bricx Command Center.
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A while ago, during a job interview with Dr. Steve Dickerson from CAMotion, I was propositioned with a design problem: design an end effector which could grapple small rolls of tape (imagine the shape of 10 quarters stacked on top of each other). These rolls collect at the bottom of a ramp in rows of four. Each row needs to be grabbed and them moved to a packing station. The moving is performed by CAMotion’s existing hardware/control software and is ancillary to the end effector design problem. It is recommended that the grappling be accomplished by an already developed vacuum-suction system. So the problem simplifies to packaging the vacuum system in the end effector such that it maximizes payload capacity and speed.

I developed a solution which took inspiration from the multiple firing chamber design of the revolver handgun. Six rows of four suction cups are positioned in a circular fashion.

Sketch	Solidworks

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I have plans to utilize the Lego NXT system for several upcoming robotics projects. The success of these projects depends on the capabilities of the kit’s ultrasonic (US) range finder. I created a test rig with the US sensor and NXT brick and conducted several experiments in order to characterize the sensor.

Test rig: wood block, measuring tape, protractor, US sensor, NXT brick (from left to right).
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