Gyroscopes... Experiments

Sooo with a gyroscope, will they work if you tilt them 90 degrees? I am asking this to see if I can make a program to measure the robots tilt and automatically recover itself.
Thanks for the help :slight_smile:

Yes. The term yaw rate gyroscope is kind of misleading, as the gyroscope can be mounted to measure pitch or roll.

As @Barin said there is nothing that would prevent you from using VEX gyro turned on its side. VEX uses MEMS gyroscope, which is not very accurate to begin with, and you may or may not notice any degradation in its accuracy when measuring pitch or roll.

The biggest problem is that the gyroscope itself measures the rate of the angle change (not the absolute angle) and then software (RobotC) integrates that rate to estimate the position. It is subject to drift errors and any vibrations or bumps could make it even worse. The errors will accumulate as the time passes and robot moves around.

Better approach would be to use VEX accelerometer, because it always measures true acceleration vector. For example, if robot doesn’t move that would be toward the center of the Earth. There are errors too, but they only depend on the quality of the device and the noise in the system and will not grow indefinitely over time like with the integrated value of Gyro.

We used accelerometer during Skyrise. If manipulator was elevated then the robot max speed would be limited depending on the elevation and accelerometer reading. By the angle at which the robot was leaning you could tell in software if you were carrying one or two cubes and whether it should be careful or very-very careful. Despite that and driver training we still managed to fall one time during States.

You could mount a potentiometer with vertical weighted bar able to spin it… when the robot leans, the bar would stay vertical and turn the pot.

Ok, thanks for the first response answer!

Thanks for the information! I never known it uses angle change instead of just normal positioning. I thought it was only for something like using the earth’s compass for the gyroscope or something… So would it be worth the $50, or is there any other methods?

Well then, right after I typed my last bit the “other method(s)” came up! Thanks, I think I may try this :smiley:

This really is a Yaw axis device. The manufacturer sells other devices to cover the other axes. (They’re all dirt cheap, but only this one is directly supported in the VEX world.) The mass and sense elements are micromachined for a particular orientation. It’s possible it will work to some degree, but it’s not guaranteed to do so, and it’s unlikely to work well.

It’s a tiny little multi-tined tuning fork-like device, with non-moving capacitive sense elements interleaved between the movable tines. The moveable element is excited so it vibrates, and the sense elements detect when the vibrations are affected by rotation around the yaw axis. (Actually measuring Coriolis effect.) Gravity will affect the moving tines in a complex way if it rotates in something other than the designed way. The calibration done inside the unit itself as well as the integration of rate information by RobotC won’t properly take the complex effects into account.

No it will not, accelerometers can though.