We need some help with our Odometry. We decided to use one horizontal wheel with an inertial sensor and one vertical wheel with a rotation sensor. Both Omniwheels are 3.25 inches. The main confusion I have is which sensors we need to use for each wheel and how to secure it to the robot to ensure they are touching the floor at all times. This is our first time trying to do Odometry since we knew it would severely help our autonomous routine.
The inertial sensor doesn’t attach to a wheel. You would use a rotation sensor for each of the two wheels and use the inertial sensor (not on an axel) for heading.
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Hey!
An inertial sensor is slightly different from a rotational sensor, it tracks the movement of your robot with an accelerometer and gyroscope. For your tracking wheels, either use a rotational sensor or a optical shaft encoder, they will be able to track the rotation of an axle, unlike the inertial sensor. Do NOT use an inertial sensor to try to tract the rotation of an axle, that will break it!!!
The Purdue SIGBots Wiki is a great resource for better understanding what each of the sensors do, as does the store description, but a quick google search should also explain their purpose.
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Where am I supposed to use the inertial sensor?
For odometery with two tracking wheels, you should use the inertial sensor for tracking the heading of the robot i.e. the direction the robot is facing, measured in degrees.
If you are using any traction wheels on the drivetrain, then the horizontal tracking wheel is useless, as it is used to measure side-to-side motion or drift with omni wheels.
If possible, use 2.75" or the new 2" omni wheels for odometry. The smaller diameter means you can get much more accurate measurements.
You don’t attach it to anything but the robot. The little hole you were attempting to fit an axel through is only meant to screw onto metal. The sensor uses an accelerometer and gyroscope to calculate heading so it doesn’t need to be given any information from the wheels. Hope this helps!
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