The article considers an example of the application of the existing mathematical model of an overhead crane to equipment with irreversible structural defects. The course of the solution of the problem is considered: obtaining primary data, finding the existing mathematical model of the crane, adapting it to the problem in question, building a computational model, modeling and analyzing the results obtained. The peculiarity of a crane as a control object is the non-typical state of the metal structure. The overhead crane is in this state after prolonged operation of the equipment with incorrect loading and control modes. As a result of such operating modes, significant wear of the wheels and the rail track take place. Worn elements must be replaced. The frequency of wheel replacement is very intensive, and is about twice a year. The process of replacing wheels with corner boxes is a very expensive procedure – it is necessary to buy equipment, stop the warehouse for a few days and attract staff. To eliminate such costs, it is proposed to conduct a simulation of the crane in order to identify methods of controlling it. The result of the first stage of modeling is the answer to the question: is it possible to operate the crane that is deformed using the correctly selected control mode.

The intensification of construction production imposes very strict requirements on the safety of construction machines. When carrying out lifting and hoisting operations using overhead cranes, production safety is primarily determined by the technical condition of the undercarriage and crane runways, as well as metal constructions. The authors deal with the issues related to modeling and research of the stress-strain state of metal structures of an overhead crane. A model of the crane metal structure is proposed, which includes the main and end box-section crane girders. To study possible geometric movements of the crane, a model of an overhead crane was designed in KOMPAS-3D software environment. The model contains main and end box-section girders. The model allows determining the maximum possible misalignment of the crane and runout of one of the sides. To determine the bending, tensile and compressive stresses in the bridge truss and the deformations of the crane metal structures, depending on the working loads, a 3D model of the bridge crane was created in the ADW Winmachine software environment. With its help, the bending stiffness of the crane bridge was established. These values are necessary to compile a mathematical model of an overhead crane as a control object in the synthesis of an automatic control system.

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Abstract.The most effective methods of organizing construction work are complex mechanization and automation of construction. Complex mechanization allows selecting the machines participating in the construction process according to their productivity. In this regard, it is necessary to take into account the structural features of construction machines that affect the overall pace of work. In order to shorten the cycle time, the design of a modern excavator's hydraulic system ensures the combined operation of two degrees of mobility in pairs: platform-boom, boom-arm, and arm-bucket. When designing and creating a system for automatic control of excavator actuating mechanisms, it is necessary to take into account the interrelation and mutual influence of hydraulic drives when working together from a source of limited power, the pump station of an excavator. Such a time combination of operations is possible when carrying out transportation to move the bucket to load and unload, while soil excavation is performed by turning the handle or bucket, and in these conditions, a large load of the feeding power station does not allow combining these operations. The paper presents a structural diagram of the concurrent operation of two hydraulic excavator actuators, which reflects the existence of connections between the hydraulic motors of the actuators.