Seismic　isolators　have　been　extensively　utilized　in　the　field　of　structural　vibration　control　due　to　their　superior　control　effectiveness　in　reducing　absolute　acceleration　responses.　However,　this　effectiveness　comes　with　a　compromise　on　large　isolation　deformation,　which　may　result　in　various　issues,　such　as　pounding　and/or　unseating　damages　of　bridge　decks.　To　address　these　issues,　a　negative　stiffness　enhanced　tuned　mass　damper　(NS-TMD)　was　proposed,　aiming　to　minimize　absolute　acceleration　while　simultaneously　limiting　isolation　deformation,　and　its　control　effectiveness　has　been　demonstrated.　However,　the　previous　studies　primarily　focused　on　single-objective　optimization　without　considering　NS-TMD　stroke,　and　the　conventional　negative　stiffness　(NS)　devices,　e.g.,　the　pre-compressed　helical　springs　with　revolute　joints,　could　not　be　well　compatible　with　NS-TMD　due　to　limited　operating　range.　To　this　end,　this　study　proposes　a　novel　NS-TMD,　which　consists　of　a　TMD　with　a　curved-type　mass　block　and　an　NS　element　based　on　a　cam-roller-spring　(CRS)　mechanism.　The　working　mechanism　of　the　novel　NS-TMD　is　first　introduced,　and　its　mechanical　model　is　formulated.　This　novel　system　is　then　applied　to　a　typical　isolated　bridge　to　illustrate　its　control　effectiveness.　Equilibrium　equations　and　state　space　formulations　of　the　system　are　derived.　Subsequently,　parametric　analysis　on　NS-TMD　is　performed,　followed　by　the　proposal　of　a　multi-objective　optimization　strategy　to　simultaneously　minimize　the　relative　displacement　of　the　bridge　deck　and　the　stroke　of　NS-TMD.　Finally,　the　control　performance　of　NS-TMD　is　systematically　evaluated.　Numerical　results　show　that　the　optimized　NS-TMD　not　only　reduces　the　deck　displacement　of　the　bridge　system　(with　a　maximum　reduction　ratio　of　49.50　%)　but　also　decreases　its　absolute　acceleration.　Furthermore,　NS-TMD　can　achieve　superior　control　performance　in　terms　of　the　deck　displacement,　while　limiting　the　stroke　within　a　reasonable　range.　In　summary,　NS-TMD　is　a　highly　efficient　alternative　to　conventional　TMDs　in　terms　of　control　effectiveness　and　feasibility.　©　2024　Elsevier　Ltd