This　article　proposes　a　hierarchical　control　strategy　to　address　semi-ABS　control　as　well　as　the　precise　clamping　force　control　problems　for　an　integrated　electric　parking　brake　(iEPB)　system.　To　this　end,　a　detailed　system　model,　including　modeling　of　the　motor,　transmission　mechanism,　friction　and　braking　torque,　is　constructed　for　controller　and　observer　design,　and　a　sliding-mode-based　observer　(SMO)　is　proposed　to　estimate　the　load　torque　by　using　the　motor　rotational　speed　without　installing　a　force　sensor.　In　addition,　a　stable　and　reliable　tire-road　friction　coefficient　(TRFC)　estimation　method　is　adopted,　and　the　desired　slip　ratio　(DSR)　is　observed　as　the　target　that　the　rear　wheels　cycle　around.　At　the　upper　level　of　the　hierarchical　control　structure,　the　desired　clamping　forces　of　the　rear　wheels　are　generated　using　a　sliding　mode　control　(SMC)　technique,　and　the　control　objective　is　to　track　the　DSR　to　make　full　use　of　the　road　condition.　At　the　lower　level,　the　motor　is　controlled　to　track　the　desired　clamping　force　generated　from　the　upper　controller.　The　hardware-in-the-loop　(HIL)　experimental　results　demonstrate　the　effectiveness　and　high　tracking　precision　of　the　proposed　strategy　under　different　road　conditions,　and　the　estimation　parameters　based　on　the　proposed　observers　are　timely　and　accurate　to　satisfy　the　control　requirements.