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The first level task among the tasks of analysis and synthesis of the control systems (CS) for multispeed transmissions (MT) is the organization of speed shifts process. The method of synthesis of electrohydraulic schemes of mechatronic CS, that is based on the theory of discrete logical devices is worked out by us (see SAE Tech. Pap. Ser. 2003-01-0319). It was shown, that there is a close relation between the structures of CS and MT. Therefore it is necessary to know the properties of MT as the object of control. The analysis of such properties is the subject of this paper. It is shown that the relation between CS and MT at the level of their structures may be described quite fully with help of three basic parameters of MT kinematics schemes: the number of freedom degrees, the number of control elements (CE), the number of speeds. The concept of generalized CS and MT is introduced.

Modern hydromechanical transmissions are equipped with electronic-hydraulic (mechatronic) control systems having much more functional capabilities compared to classic hydraulic systems. However, automatic hydraulic systems are widely used not only as the basic transmissions' control device and a mechanical part of mechatronic systems but also as an important facility providing reliability and safety of such systems. At the same time such an application has quite a number of restrictions, especially for transmissions with a great number of gearstages. One of the main reasons is the inability to control more than 3 or 4 stages of gears while using the vehicle's speed as a control parameter. It deals with the parabolic characteristic of the output pressure of centrifugal governor used as the vehicle speed sensor. This restriction can be eliminated by using a hydraulic detector of torque converter's turbine (i.e. input shaft of gearbox) speed.

Modern vehicles have a number of safety systems, main of which are basic control systems - steering and braking systems. Requirements to these systems, defined by the vehicles design safety, are regulated by the system of the international and national standards and rules. Mechatronic control systems of the hydromechanical transmissions pertain to the “yongest” automotive systems, and questions dealing with their safety don't have yet the complete theoretical and normative base. The connection between these mechatronic systems safety and their structure is investigated in this paper. The method of the safety analysis with help of the “refusal graphs” is proposed, which permits to bring out and to eliminate the possibility of the dangerous refusals capable to create the crash situations during automobile motion.

The problem of fuel consumption decrease in agricultural machinery may be addressed in several ways. One is to equip mobile agricultural machines (tractors, harvesters, sprayers, fertilizer spreaders, etc.) with on-board computers (BC) capable to measure the fuel flow rate, in particular, which will allow to decrease fuel consumption by these machines due to timely control of the technical conditions of the engine and optimization of the machine operation modes from the point of view of fuel consumption. The article describes a family of diaphragm chamber fuel flow transducers (FFT) for on-board computers of mobile agricultural machines, gives their technical characteristics and laboratory and field test results, and recommendations on connecting them to engines of various power specifications.