{fan,sensing,actuator,com,controller}={(StateSpaceModel[-(1/10), 1, (1/10), 0, ]),(TransferFunctionModel[(E^(-s δ)), ]),(TransferFunctionModel[(E^(-s/10)), ]),(TransferFunctionModel[(E^(-s/2)), ]),(TransferFunctionModel[((25+22s)/s), ])};

y0=OutputResponse[SystemsModelFeedbackConnect[SystemsModelSeriesConnect[controller,fan]],UnitStep[t-2],{t,0,20}];
Plot[y0,{t,0,20},PlotRange->All]

remotesys=SystemsModelSeriesConnect[actuator,SystemsModelSeriesConnect[fan,sensing]];
comsys=SystemsModelSeriesConnect[SystemsModelSeriesConnect[com,remotesys],com]

y1=OutputResponse[SystemsModelFeedbackConnect[SystemsModelSeriesConnect[controller,comsys/.δ->1/5]],UnitStep[t-2],{t,0,10}];
Plot[%,{t,0,10},PlotRange->All]

smith=SmithDelayCompensator[comsys,controller];
cl2=SystemsModelFeedbackConnect[SystemsModelSeriesConnect[smith,comsys]];

responses=Prepend[Table[OutputResponse[cl2/.{δ->del}, UnitStep[t - 2], {t, 0,20}],{del,{1/5,5,10,15}}],y0];

Plot[responses, {t, 0,20}, PlotRange -> All,PlotStyle->Prepend[Table[Dashed,{4}],Thick],ImageSize->Medium]