Wheeled Mobile Robots:Wheel Types and Geometry of wheel.

 Suggested topic  :Locomotion in mobile robotics

Wheeled mobile robots:

The wheel is one of the widely used locomotion techniques in mobile robotics. as its efficiency and simplicity of mechanical implementation. and in addition to these qualities body balancing is not a constraint in general wheeled mobile robot scenarios, because in most cases the wheeled robots are designed as all wheels are in contact with the ground so just 3 wheels are enough to ensure stability.

Wheel Design:

Wheel designs are classified into 4 types in general.

1. Standard wheel:

 Two degrees of freedom -->rotation around the wheel axis and contact point,
 Having a primary axis of rotation so it is highly directional.
 -To move in a different direction the wheel should first steer along a vertical axis .

Standard wheel for robotics


2. Caster wheel

two degrees of freedom rotation around an offset steering joint.

Caster wheel and geometry of wheels

3. Swedish wheel

Three degrees of freedom -->rotation around the wheel axis, around the roller, around the contact point.Functions as a standard wheel with Low resistance in direction change.

Swedish wheel in Robotics


4. Ball or spherical wheel:

  multi-degree of freedom Complete Omni-directional.

Requirement of suspension system :

Regardless of the type of wheel, the robot is designed for multiple /all-terrain fields and with more than 3 wheels requires a suspension system to maintain wheel contact with the ground.

The Geometry of the wheel :

The term wheel Geometry is used to represent wheel arrangements.
wheel geometry = How we arrange wheels in a system
The wheel geometry and type of wheel are closely linked to each other.
so, when we design the locomotion mechanism of a robot we have to decide on these two parts simultaneously.
The fundamental characteristics like maneuverability, controllability, and stability of robots depend on the combination of wheel geometry and type of wheel.

Maneuverability:

Capability of being steered or directed.

Controllability

Refers to the ability to drive a system from one state to another.

Dynamic stability

The measure of the ability of a robot to maintain its balance while in motion.

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Read:

Locomotion in mobile robotics. 

What is mavros?.

Introduction to robotics. 

Different types of robots?

ROS : 5 Major advantages of using ROS.

Important branches of robotics?