Summary: This note presents a new memoryless
controller design method for singular systems with delayed state and control by the linear matrix inequality (LMI) technique. Since lemma and theorem in the paper by S.-S. Hung
and T.-T. Lee
[J. Franklin Inst. 336, 911–923 (1999; Zbl 0979.93031
)] are incorrect, the errors are pointed out. And then we present the new state feedback
controller design algorithm for singular systems with delayed state and control by the LMI approach. All solutions including controller gain can be obtained simultaneously because the presented condition is an LMI regarding all variables.