This　article　studies　the　cooperative　tracking　control　problem　for　multiple　mobile　robots　over　a　directed　communication　network.　First,　it　is　shown　that　the　closed-loop　system　is　uniformly　globally　asymptotically　stable　under　the　proposed　distributed　continuous　feedback　control　law,　where　an　explicit　strict　Lyapunov　function　is　constructed.　Then,　by　investigating　the　convergence　rate,　it　is　further　proven　that　the　closed-loop　system　is　globally　K-exponentially　stable.　Moreover,　to　make　the　proposed　control　law　more　practical,　the　distributed　continuous　feedback　control　law　is　generalized　to　a　distributed　sampled-data　feedback　control　law　using　the　emulation　approach,　based　on　the　strong　integral　input-to-state　stable　Lyapunov　function.　Numerical　simulations　are　presented　to　validate　the　effectiveness　of　the　proposed　control　methods.