Skip to 0 minutes and 2 secondsOK. It's time to do the first exercise. And this is about working out how you need to command the robot to move around.

Skip to 0 minutes and 12 secondsThis is the web page you will use. It's got a title. It tells you a little bit about what's going on, gives you the task that you do. It tells you how you can use the keyboard to do the particular controls. The web page is looking like this. But if your browser is longer than wider, it might appear like that. But I'll show it in the first mode. So what you do in this particular exercise is to specify what the speed should be of the left motor and for the right motor, and to see what actually happens. Now, when you specify a speed, as you view the robot from the outside, a positive speed means the wheel will turn clockwise.

Skip to 0 minutes and 58 secondsTo explain what I mean, I just quickly go over to this web page. Here, we've got the two wheels of the ERIC robot. Here, you're looking at the right wheel from the outside. So the wheel is in front of the circuit board and the battery pack. Here, you're looking from the same side, where you can see the battery pack and the board in front of the wheel. And at the moment both, speeds are positive. So the left wheel is going anti-clockwise, and the right wheel is going clockwise. So if I want the left wheel to go in this direction, I need to unclick that.

Skip to 1 minute and 34 secondsAnd now, both wheels seem to be going in the same direction, which you would want to do, perhaps, to make the robot go forward.

Skip to 1 minute and 45 secondsSo back to the web page. What you need to do is to put different numbers in. So you put a number in here. It's an integer between minus 40 and 40. If I put in 4 and I press Start, the robot does that. If I want to make that 0, I could make it 0, make the other one 4. I can press Stop, and then Start again. If I put 4 in and start, again, the thing goes round. But, to stop it, I have the option of reversing the connection of the left motor, so that now, we shall see the robot going in a straight line. It's now going off the screen.

Skip to 2 minutes and 31 secondsWhen that happens, you can just click into the middle and it's there. So those are the sort of commands that you need. In terms of using the keyboard, if I type the L key I'm ready into the field where I can put in a speed. So I can type in 8. If I type R, I can go to do the right speed. And if I type W, it toggles the reverse left motor connection. And S starts and stops. So that's the web page. So another thing you can do is you can move the robot up and down using the M, J, K, and I. So M moves it down. J moves it to the left.

Skip to 3 minutes and 10 secondsSo what you need to do in this particular exercise is to see what happens when you try different values for the left and the right motor. Work out what you have to do to make the robot go forwards or go backwards, or spin to the left or to the right, and investigate the reverse left motor option. Have fun.


Before you get started on your first simulation, watch this video to see how ERIC, the University’s very own mobile robot, responds to simple commands embedded within a computer program.

Looks easy? Or not so easy? Curious to find out how to ‘drive’ a robot for yourself ? Great! Now you’re ready to move onto the the next step and master the basic instructions that will enable you to get started.

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This video is from the free online course:

Begin Robotics

University of Reading