Holonomic constraint

Imagine you are playing with blocks and you can move them around in any direction you want, like forward, backward, left, right, and even diagonally. Now, if you want to make it more challenging, you can say that the blocks can only move in a certain way, like only forward and backward, but not sideways. This is called a constraint.

A holonomic constraint is a type of constraint that restricts movement in a certain way. It means that if you move the object in any direction, you will still have the same amount of freedom to move it again in another direction. For example, if you have a toy truck that can move forward and backward, left and right, and even spin in circles, then it has holonomic constraints.

However, if you have a toy car that can only move forward and backward, then it does not have holonomic constraints because it has lost some of its freedom to move in other directions.

In simpler terms, a holonomic constraint means that you can move something around without any limitations or restrictions like a toy truck. But, if there are constraints that limit the ways you can move something, like a toy car that can only go forward and backward, then it's no longer holonomic.