Abstract: This basic robot planning systcm chooscs a motion path to avoid collision with obstaclcs inworkspace.With a camera above the workspace the computer vision can give a simple dcscription of theworld model.The presented algorithm transfers a cartesian description of obstacles into the coordinatcs ofthe first three joints of a manipulator.The free space is described hierarchically by a two-level representa-tion,and a two-level optimization is used for the path planning.Experiments show that the whole systemcan be realized by an IBM—PC with very small memory.The average computation time for one obstacle is10s.