The design of a sensitivity model of a digital servosystem with cascade control and dead-beat control algorithms is described. The problem of sensitivity model instability is discussed and a possible approach to obtaining a stable model proposed. An explicit relation was derived relating the changes of dead-beat control algorithm parameters to the absolute sensitivity functions of the measured output variable. The computer simulation results of parameter synthesis applied to the dead-beat dc motor armature current and angular speed control algorithms indicate that the tuning of control algorithm parameters is completed after a single iteration for smaller changes of drive parameters, while two or more iterations are required in case of large changes of drive parameters. The developed method for synthesis of time optimal controller parameters could be suitable for adaptive control with self-tuning of control algorithm parameters.