Lin et al

Lin et al.

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• Parameters of the Robot
• Procedure
• Calibration

Parameters of the Robot (up)

• Di: diameter of the wheels
• n: reduction ratio ([n:1]) of the transmission coupled with each motor of the wheels
• Ce: resolution (ppr) of the encoder coupled with each motor of the wheels

Three-wheeled omnidirectional robot:

• l: distance from the robot's geometric center to the wheels' contact point with the ground

Four-wheeled omnidirectional robot:

• l1: distance between the robot's front and rear wheels
• l2: distance between the robot's left and right wheels

Procedure (up)

1. Measure the absolute position and orientation (note: the method requires both position and orientation data) of the robot and initialize the odometry system with that position
2. Run the robot through a curvilinear motion in CW direction (ω < 0):
   • Set the initial radius (R0) taking into consideration the available space (ω0 = v / R0 or ω0 = vn / R0)
   • Set a radius decreasing ration (r%)
   • Update the linear velocities of the robot after each l 180º curve (v{l+1} = r% * v{l} or vn{l+1} = r% * vn{l})
   • Measure the absolute pose after the robot has gone through 0.5m linear displacement (based on odometry)
3. Repeat steps 1-2 if needed (for noise robustness)
4. Repeat steps 1-3 in CCW direction
5. Repeat steps 1-4 with linear velocity in direction of vn
6. Compute the kinematic parameters using the least-squares algorithm
7. Adjust the robot parameters given the result from the previous step

Calibration (up)

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