Wheels - NTheuws/linorobot2_software GitHub Wiki
The wheels that will be used depend on the type of robot you want to use. Here the available types and the amount of wheels required will be determined.
There are 3 different types of robots that're currently supported:
- 2 Wheel drive (2WD), 2 wheels + 1/2 caster wheels
- 4 Wheel drive (4WD), 4 wheels
- Mecanum, 4 mecanum wheels (omnidirectional)
Depending on the choice you'll be needing more or less wheels, motors and motor drivers. This will be mentioned in each part, but do keep it in mind.
In case you're building a 2WD robot, for the robot to drive properly, 1 or 2 caster wheels are used to keep the balance without being in the way of the robot's movement. So if this'll be your choice, you're looking to get 2 wheels and 1 or 2 caster wheels.
Since the robot isn't capable of turning the wheels, it'll be turning motors on and off to rotate and move. For this all 4 wheels will be powered the same way. If 4WD is your choice, you'll be needing 4 wheels.
These are omnidirectional wheels, which uses rollers that're placed diagonally on the surface of each wheel. When the wheels rotate, they'll be moving sideways instead of straight forwards/backwards. When powering certain motors the direction of which the robot moves can be determined. This enables the robot to not only make the normal movements a 2WD and 4WD can do, but also move sideways and diagonally.
Figure 1 shows the top view of a robot and the orientation of the motors and wheels.
For 2WD, make sure to use MOTOR1 and MOTOR2. Both Mecanum and 4WD use all 4 motors.
In case of mecanum wheels, it also shows the orientation of the rollers on the 4 wheels. The wheels' orientation is very important. When looking at the robot from the top, the rollers on the wheels have to point towards the center of the robot. This should automatically mean the rollers on the bottom of the wheels should form a diamond shape.
The arrows show the X and Y-axis for the Inertial Measurement Unit(IMU), this will be mentioned again later.
Figure 1: Orientation of the robot
Depending on the choice you'll be needing a different amount of wheels:
- 2WD: 2 wheels and 1 or 2 caster wheels.
- 4WD: 4 wheels.
- Mecanum: 4 mecanum wheels.
Previous step: Required hardware
Next step: Motor drivers