This　paper　solves　the　leaderless　consensus　problem　of　multiple　nonholonomic　mobile　robots　over　undirected　graphs　by　a　novel　distributed　event-triggered　controller　where　a　persistently　exciting　signal　is　utilized　to　overcome　the　nonholonomic　constraint.　A　new　triggering　mechanism　containing　two　triggering　conditions　is　developed　with　respect　to　the　cascaded　structure　of　the　closed-loop　system　which　makes　the　leaderless　consensus　problem　tractable　in　the　sense　that　we　no　longer　need　to　find　any　strict　Lyapunov　function　for　the　entire　closed-loop　system.　It　is　proven　in　order　that　the　solution　of　the　closed-loop　system　is　uniformly　globally　bounded,　that　the　full　consensus　subspace　is　uniformly　globally　exponentially　attractive,　and　that　the　Zeno　behavior　shall　never　occur.　A　numerical　example　is　provided　to　validate　the　effectiveness　of　the　proposed　controller.　(c)　2025　Elsevier　Ltd.　All　rights　are　reserved,　including　those　for　text　and　data　mining,　AI　training,　and　similar　technologies.