Weed　control　is　a　huge　problem　in　organic　vegetable　farming.　Even　though　there　are　machines　available　for　inter-row　weeding,　manual　weeding　is　the　only　choice　for　adequately　controlling　weeds,　particularly　in　the　space　between　plants　(also　called　intra-row　weeding).　Unfortunately,　manual　weeding　is　highly　labor　intensive　and　costly.　Robotic　or　automatic　weeding　would　be　one　of　the　potential　solutions　for　solving　the　problem.　However,　some　of　the　technical　challenges　need　to　be　removed　for　automatic　weeding.　One　of　such　technical　challenges　is　that　the　weeding　end-effector　needs　to　reach　target　precisely　to　remove　weeds　located　very　close　to　the　plant　while　the　robotic　vehicle　is　continuously　moving　on　a　generally　uneven　and　uncertain　field　surfaces.　This　study　was　aimed　at　assessing　the　performance　of　an　end-effector　auto-leveling　system　designed　to　accurately　control　the　position　of　weeding　end-effectors　during　field　operations　in　vegetable　crops.　The　performance　assessment　was　conducted　via　a　set　of　field　experiments　using　a　specifically　designed　and　fabricated　robotic　platform　with　leveling　system.　To　achieve　the　desired　level　of　performance　in　actual　field　conditions,　the　prototype　system　required　to　maintain　the　end-effector　base　at　horizontal　position　within　a　+/-　0.25　degrees　angular　error　when　the　prototype　is　operating　under　a　field　condition　causing　up　to　-11　degrees　to　11　degrees　variation　in　roll　and　pitch　angles.　The　test　results　verified　that　the　developed　end-effector　base　leveling　system　could　maintain　the　drift　of　the　end　effector　tip　position　within　18　mm,　and　maintain　the　roll　and　pitch　angular　error　within　0.2　degrees.　Meanwhile,　based　on　the　concept　of　proof　research,　it　is　safe　to　say　the　corresponding　position　error　caused　by　angular　error　of　the　leveling　plate　was　limited　in　1　mm　when　the　leveling　plate　at　a　height　of　50　cm　under　field　condition.　The　experiment　results　can　prove　that　the　leveling　system　can　efficiently　reduce　the　effect　of　the　rough　field.　(C)　2018,　IFAC　(International　Federation　of　Automatic　Control)　Hosting　by　Elsevier　Ltd.　All　rights　reserved.