Izvestiya MGTU MAMI

BACKGROUND: Existing design methods for axial-piston pumps are optimized for operation with mineral oils and typical materials. The methodology for designing pumps with valve distribution specifically adapted for use with highly corrosive seawater and modern wear-resistant friction pairs remains unexplored. This study aimed to address this gap.

AIM: Development of a design methodology for an axial-piston pump with valve distribution, intended for operation using seawater as the working fluid.

METHODS: The selection criterion was the compatibility of the pump component design with seawater operation. The focus of the study was the performance and reliability of key components. The target parameters were valve response rate, bearing load capacity, and wear resistance of the “nitrided titanium – Victrex WG102 plastic” friction pair. The methods employed included mathematical modeling, calculations based on well-known fluid dynamic methods and wear theories.

RESULTS: The calculations of the proposed design showed that the valve opening speed increased by 2.7 times compared to the standard design, while the closing speed increased by 4 times. The tilt angle of the thrust sliding bearing sectors was 0°0’23”; testing confirmed the bearing’s load capacity.

CONCLUSION: As a result of the study, the design methodology for an axial-piston pump using “seawater” as the working fluid was developed.

BACKGROUND: Peristaltic pumps are widely used in the pharmaceutical, chemical and food industries, microbiology, robotics, and other fields requiring sterility and precise flow rate. Currently, in addition to the most common rotary peristaltic pumps, linear peristaltic pumps are also produced. Their drive design typically allows to implement relatively simple and accurate flow rate control. However, there are only a few peristaltic pump design methodologies that focus on rotary or diaphragm pump designs.

AIM: Obtaining mathematical dependencies, physical quantities and a calculation algorithm necessary for the design calculation of a linear peristaltic pump, which allows to determine its main parameters by solving the optimization problem for given values of pump flow and pressure.

METHODS: In the considered design the pump tube is compressed transversely by three flat pushers in turn. The study utilized a mathematical flow model derived from the Bernoulli equation, a bisection method for extremum searching, and numerical simulations using the Finite Element Method and the Finite Volume Method.

RESULTS: The change of tube shape of the pump depending on its geometric parameters and material properties was studied. The necessary for design calculation function that approximate the dependence between the geometric parameters of a compressed tube were obtained. The dependence of the gap in the compressed region of the tube from the magnitude of the compressive force was determined. An algorithm for calculating the main pump parameters was developed.

CONCLUSION: A design calculation methodology for a peristaltic pump with a linear tube and three compression pushers, designed for pumping highly viscous liquids, has been developed. However, further refinement of the methodology remains necessary, as the optimal tube compression ratio and the impact of the pushers shape on pump performance remain unclear.

BACKGROUND: The study of dynamic processes in the engine-load system is one of the potential resources for improving the performance of internal combustion engines (ICEs) operating in various types of vehicles. Currently, mathematical modeling methods are useful for studying these complex processes, as their effectiveness is significantly reduced by the time and cost of in-kind testing. However, despite the obvious potential of this approach, mathematical modeling of small-sized multi-purpose diesel engines operating in vehicles, as well as dynamic processes in the engine-load system, have not yet received attention in the scientific literature.

AIM: Development of a mathematical model of the “small-sized multipurpose diesel engine–load” system using a self-propelled vehicle as an example, taking into account intra-cycle and inter-cycle dynamics.

METHODS: This paper considers an improved mathematical model of the ‘’small-sized multipurpose diesel engine–load’’ system. The model’s system of equations is based on the laws of conservation of energy, mass, and the equations of motion of rigid elements. It includes differential equations for the rate of change of the working fluid’s temperature and density in the cylinder, an ideal-gas equation of state, and differential equations for the change in angular velocity and engine shaft angle. The time-varying load torque was determined using a mathematical model of the chassis based on vehicle dynamics theory. The mathematical description was implemented using the PascalABC programming language.

RESULTS: The mathematical model was tested using the TMZ-450D (1Ch8.5/8.0) small-sized air-cooled multipurpose diesel engine as part of a self-propelled vehicle’s prototype. The paper presents the results of modeling intra-cycle (pressure, temperature, instantaneous angular velocity) and inter-cycle changes in parameters and dynamic modes, obtained for the acceleration of a self-propelled vehicle from rest on a level section of road at the first gear. The intra-cycle dynamics of the system are represented by graphs of the time-varying pressure and temperature in the cylinder and the instantaneous crankshaft rotational velocity. The inter-cycle dynamics are represented by graphs of the cycle-averaged values of rotational velocity, power, fuel consumption, engine torque, and load torque.

CONCLUSION: The developed mathematical framework and software enable solving problems of determining the influence of the design and operational parameters of the “small-sized multipurpose diesel engine–load” system on the operation of the diesel engine in a vehicle, and in particular, on its traction dynamics. The proposed approach can form the basis for a method for determining the reasonable parameters of a small-sized multipurpose diesel engine, taking into account the properties of the energy consumer with which the engine is to operate in a single system.

BACKGROUND: The traction electric drive control system is one of the key mechatronic systems of an electric vehicle, which determines the implementation of acceleration dynamics, regenerative braking, and motion stabilization. The complexity of the traction electric drive structure, the expansion of the number of modes and operating states, as well as the need to interact with third-party components, requires the structuring of the upper-level software architecture. A structured approach simplifies the development and scaling of the traction electric drive control system. Therefore, the development of a functional architecture and structure with an algorithm registry is relevant.

AIM: Development of the functional structure and the algorithm registry of the mechatronic control system for the vehicle’s traction electric drive, which ensures the generation of control actions, data processing, diagnostics, and monitoring of the mechatronic system’s safety.

METHODS: The traction electric drive control system software has been decomposed. The data flows and software module interactions have been analyzed to create the functional structure and the algorithm registry.

RESULTS: The functional structure of the software of the mechatronic control system of the traction electric drive has been developed. The composition of functional groups, functions and algorithms providing processing of the received data, determination of driving modes, formation of traction and regenerative torque, limitation of slip of driven wheels and axles, as well as control of safe operation of the mechatronic system is presented.

CONCLUSION: The proposed functional structure and algorithm registry allow to organize the software of the mechatronic traction electric drive control system, to ensure scalability and integration with third-party systems. The results obtained can find application in the development of the upper-level software of the mechatronic traction electric drive control system.

BACKGROUND: The JGB37-520 direct current (DC) gear motor series are widely used in robotics and low-power electric drive systems; however, experimentally validated data on their electromechanical parameters lack in open scientific sources. The present study aims to fill this gap by means of experimental determination of the parameters of the motor as an integral electromechanical device.

AIM: Experimental determination of the main electromechanical parameters of the JGB37-520 DC motor equipped with a reduction gear and an incremental encoder, used in low-power electric drive systems, for the subsequent application of the obtained data in the development of mathematical models and control systems.

METHODS: The study object was a JGB37-520 DC motor assembled with a reduction gear and an incremental encoder. The motor without the gearbox was not considered due to the lack of practical application. The study was conducted under laboratory conditions. The winding resistance and inductance were determined using direct electrical measurement methods. The determination of the k_e and k_m coefficients, as well as the moment of inertia of the output shaft, was based on experiments with a mechanical load of known weight, where the winding current, angular velocity, and angular acceleration of the shaft were measured. The measured indicators included the electrical and mechanical parameters of the motor required for its mathematical description.

RESULTS: During the study, one sample of the JGB37-520 DC motor with a reduction gear and an incremental encoder was experimentally studied. The winding resistance and inductance, the moment of inertia of the output shaft, the kₑ coefficient relating angular velocity to back-electromotive force, and the kₘ coefficient relating electromagnetic torque to the winding current were determined. The obtained values describe the motor as a single electromechanical object and can be used in building the motor’s mathematical model.

CONCLUSION: As a result of the conducted study, the main electromechanical parameters of the JGB37-520 motor with a reduction gear and an incremental encoder were experimentally determined. The obtained data make it possible to use this motor in problems of modeling and synthesis of control systems for low-power electric drives.