Inpracticalrobotmotionplanning,robotsusuallydonothavefullmodelsoftheirsurrounding,andhencenocompleteandcorrectplanexistsfortherobotstobeexecutedfully.Inmostreal-worldproblemsarobotoperatesinjustapartially-knownenvironment,meaningthatmostoftheenvironmentisknowntotherobotatthetime