High-resolution　imaging　has　become　a　development　trend　and　is　widely　used　in　military　and　civil　fields.　As　the　carrying　equipment　of　imaging　system,　the　speed　stability　of　tracking　turntable　is　the　basis　of　high-resolution　and　stable　imaging.　At　present,　in　the　aerospace　field,　there　are　high　requirements　for　peak　power　dissipation　and　holding　torque,　so　flexible　joints　such　as　harmonic　gear　drive　are　mostly　used　to　realize　the　function.　The　characteristics　of　flexible　load　have　a　great　impact　on　the　characteristics　of　motion　control,　which　is　easy　to　cause　mechanical　resonance,　lead　to　system　instability,　and　have　a　great　impact　on　speed　stability　and　position　tracking　accuracy.　Therefore,　it　is　necessary　to　study　the　servo　system　of　flexible　load.　In　order　to　solve　the　problems　of　high-precision　position　control　and　speed　stability　at　low　speed　of　flexible　turntable　with　uncertain　load,　on　the　one　hand,　we　comprehensively　consider　the　advantages　and　disadvantages　of　semi-closed-loop　and　full　closed-loop　control　and　design　a　dual-position　loop　feedback　control　system　combined　with　the　analysis　of　dynamic　equation　to　realize　speed　stability　and　high-precision　position　control.　On　the　other　hand,　according　to　the　requirements　of　the　speed　stability　at　low　speed　of　the　turntable,　the　tracking　differentiator　(TD)　is　designed　innovatively　through　the　language　three-point　interpolation　subdivision　and　five-point　pre-deduction　calculation　method.　Finally,　a　dual-position　loop　LLADRC　(language　linear　active　disturbances　rejection　controller)　control　method　based　on　harmonic　gear　drive　is　studied.　By　comparing　the　semi-closed　loop,　dual-position　loop,　dual-position　loop　LADRC　(linear　active　disturbances　rejection　controller,　ADRC),　and　dual-position　loop　LLADRC　methods　through　simulation　analysis,　it　can　be　shown　that　the　double　position　LLADRC　control　method　is　obviously　superior　to　other　schemes　in　terms　of　rapidity,　speed　stability　at　low　speed,　and　position　tracking　accuracy.　The　theoretical　research　is　verified　by　experimental　test.　When　the　given　speed　is　0.1°/s,　taking　the　pitch　axis　as　an　example,　the　pitch　speed　error　is　0.0039°/s　(3σ).　When　the　maximum　speed　of　the　given　curve　is　20°/s　and　the　maximum　acceleration　is　16°/s,　the　position　tracking　error　is　0.0025°　(3σ).　This　control　method　solves　the　problems　of　system　instability　and　low-speed　stability　in　high-precision　control　of　turntable　system　based　on　harmonic　gear　drive　and　provides　a　method　for　high-precision　control　of　high-resolution　imaging　turntable.　©　2022　Yu　Cao　et　al.