The paper presents an optimized synthesis method of the symmetrical 7-RR(RRRR)RR seven-bar linkage. The proposed synthesis method consists in the analytical computation of the links’ lengths of the seven-bar linkage by avoiding singularities in an imposed dexterous workspace. The aim of this method is to obtain the largest variation of the mechanism’s height between its folded position (minimum configuration) and its extended position (maximum configuration) while also keeping the size of the robot in the horizontal direction as minimum as possible, by considering the minimum input transmission angle. The most optimized seven-bar linkage structure is intended to be used for the design of a disinfection robot with folding mechanism in order to be able to disinfect the hard-to-reach areas from the medical environment.