**What is path planning?**

Path planning as the name suggests is the ability of the robot to plan a collision free path from its current location or configuration to a goal configuration.(See figure below)

**What are the main classifications of planning algorithm?**

Path planners are broadly classified as follows

**Geometric Planners:** Geometric planners compute paths that are collision free. They incorporate the size of the robot while computing collision free paths

**Kinematic Planners:** Mere geometric plans do not entail their execution since the robot kinematics may not permit them to do so. For example a geometric planner for a car may compute a path that allows for lateral motion of the car as long as it is collision free. However a car cannot move laterally since its kinematics prevent it from doing so.

**Dynamic Planners:** During motion on rough and uneven terrain the terrain ground interactions play a crucial role in determining the feasibility of a kinematic and geometrically consistent path. Planners that consider the dynamics of the vehicle and plan paths that are dynamically feasible are considered dynamic planners.

**What are the prominent geometric planning algorithms?**

Geometric planning algorithms have their roots in computational geometry. The popular algorithms include the visibility graph computed over a configuration space[1], the vornoi diagrams [2], cell decomposition methods [3] and grid based gradient descent methods [4]