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Skip to 0 minutes and 1 second Now going to talk about the Grimblebot, which is a self-balancing robot which utilises ultrasonic sensors and closed loop control. The Grimblebot, which is named after lecturer James Grimbleby, is a self-balancing robot. It was initially developed as a final year project, and then it became a second year project that a lot of students did if they were studying to do electronic engineering. Effectively, it uses ultrasonic sensors to detect if it’s falling over, and then uses closed loop feedback control to stay upright. So that’s what it looks like. So wheels at the bottom, circuit board, batteries, and so forth, and some electronics here, and this is its ultrasonic sensor. So it senses by sending an ultrasonic beam downwards.

Skip to 0 minutes and 54 seconds It echoes off the carpet and comes back, so therefore, the device can work out how far away is from the carpet. If it detects that it is leaning– for instance, it’s leaning to the right, then it will drive the motors to the right to get it back up to balance again. Let’s watch it in action.

Skip to 1 minute and 15 seconds Here we are. You see the Grimblebot. If it’s shaking around and starting to lean down, it moves. If it goes too far, it goes back again. As you can see, quite nicely. It’s controlling itself.

Skip to 1 minute and 32 seconds See it from the back. Move it around to the front.

Skip to 1 minute and 41 seconds So in summary, what we have here is a nice example of closed loop control, which has been achieved with a mixture of electronics, sensing, control theory for balancing, implemented using its own computer.


The Grimblebot is a self-balancing robot which utilises ultrasonic sensors to detect if it is falling over and closed loop control to stay upright. To find out more about the Grimblebot and to watch it in action, take a look at this video.

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Begin Robotics

University of Reading

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