In this paper identification of dynamic systems under conditions of unlubricated friction is analyzed and problems related to the dynamics of materials frictional interaction are considered. Algorithms of automatic control and catastrophe theory were used to study frictional properties of materials. The authors developed a special device to study tribotechnical characteristics of materials. A mathematical algorithm for studying the tribological contact in the form of a tribological system based on the input-output models is presented. The scope of application, requirements for input and output data, use of the algorithm in case of contact surface evolution are determined. The results obtained indicate the nonlinear friction behavior for friction couples PTFE-Copper, PTFE-Steel and PTFE-Titanium. The relationship between the stability of the system and changes occurring in the tribocontact was found. Processing of obtained dynamic characteristics of tribological interaction of friction couples shows periods of material wear and energy consumption for the formation of a new surface in terms of time