Mobile robot kinematics

Wheel kinematic constraint
• The first step to a kinematic model of the
robot is to express the constraints on the
motions of individual wheels.
• Under the assumption that wheel undergoes
motion only under conditions of pure rolling
and rotation about the vertical axis through
the contact point, there are two constraints
for every wheel type to be considered.

Wheel kinematic constraints
• 1 st constraint
-concept of rolling: wheel must roll when
motion takes place in the appropriate
direction
• 2 nd constraint
-concept of no lateral slippage: the wheel must
not slide orthogonal to the wheel plane.

Wheel kinematic constraints
• Types of wheels:-
1. Fixed standard wheel
2. Steered standard wheel
3. Castor wheel
4. Sweedish wheel
5. Spherical wheel
• There are two sets of kinematic constraints for each
wheel type:
i. Rolling constraint
ii. Sliding constraint

Mobile robot maneuverability
• Degree of mobility
-
• Degree of steerability
• Degree of maneuverability
• Three wheel configurations

Mobile Robot Workspace
• Holonomic and nonholonomic
• degrees of freedom