Segway New Zealand’s managing director Philip Bendall completed a degree in Mechanical Engineering at the University of Auckland. So he was thrilled when Dr Karl Stol of the School of Engineering purchased two Segway Personal Transporters (PTs) in 2006.
One Segway PT – an i180 model – is used primarily for promotional purposes, such as interesting secondary school students in pursuing the profession of Engineering. The other – a p133 model – has been put to work in the laboratory, and modified almost beyond recognition. It has also been mounted with frickin’ laser beam! For peaceful purposes, of course.
The p133 has been part of many research projects over the last six years. The essence of how a Segway PT works is embodied in the engineering field known as Dynamics and Controls. This year, PhD student Ronald Chan is one of several utilising the highly modified p133 as a research platform.
Ronald’s project and those of other students seek to improve the performance of self-balancing machines used for autonomous robotic purposes. The first project in this area was entitled “Development of a Two-Wheeled Balancing Platform for Autonomous Applications”).
Another project uses a laser range-finder and a special algorithm to improve riding up and over bumps (“Step detection and Traversal by a Two-Wheeled Robot”).
Such dynamic problems are complex to model and are a very interesting field of study. There is little doubt that balancing machines will become more common and more useful as this decade progresses.
The Mechanical Engineering department decided to replace the p133’s two Controller Boards and Balance Sensor Array (the gyroscopes and accelerometers) with their own units, as the proprietary code belonging to Segway, Inc. was not available to them. The Balance Sensor Array (BSA) has been replaced by an off-the-shelf IMU (Inertial Motion Unit) that provides similar data to the BSA, but also adds an electronic magnetic compass (however this component cannot be used because the strong magnetic fields created by the p133’s electric motors generate interference). The Controller Boards have been replaced by a standard PC that communicates wirelessly with the p133 and runs the Mechanical Engineering department’s own custom software that balances and moves the p133 around. The p133’s motors are controlled with signals via a RS-232 interface, and a USB interface has been added to handle the increased data transfer rates required for certain applications. Sharp-eyed observers will notice the gearboxes hhave been deliberately installed upside down to raise the height of the platform.