19 research outputs found
Accelerated optimization evaluation of the main technical characteristics of the passenger aerial ropeway
In the article the mathematical model and the technique of the accelerated optimization estimation of the main technical characteristics of the passenger aerial ropeway (step and height of intermediate supports, tension force of the bearing ropes) are developed. To calculate the optimal values of these technical characteristics, the task of technical and economic optimization was previously developed. The optimization task was based on the minimization of the objective function — the cost of the aerial ropeway construction, taking into account a number of structural constraints. The accelerated optimization estimate is based on the fact that the position of the minimum point of the objective function should be searched along the line of one of the mentioned constraints – constraint on the minimum of tension force of the bearing ropes. This allowed us to propose two ways of accelerated optimization evaluation: 1) reduction of the dimension of the optimization problem; 2) replacement of the search for the minimum of the objective function by the solution of a nonlinear algebraic equation. The proposed algorithm of accelerated optimization evaluation of the main technical characteristics of the passenger aerial ropeway allows to obtain exactly the same values as the result of solving the previously developed problem of technical and economic optimization, but with the use of more simple mathematical methods
Modeling of working processes in the throttle-adjustable hydraulic drive of manipulation systems with conjoint movement of links during operation of mobile machines
The article proposes a functional-structural scheme and a mathematical model of working hydrodynamic processes in a throttle-adjustable hydraulic drive of handling systems (cranes-manipulators) of mobile transport-technological machines during the conjoint movement of two links. The model allows to perform computer simulations of the kinematics and dynamics of the elements of the metal structure of the manipulator and hydrodynamic working processes in the hydraulic drive as jointly occurring and interacting processes. A description of a computer program that implements the developed mathematical model is given. The program allows to calculate the change in time of movement, speed and acceleration of the moving link of the handling system, pressure and volumetric flow rate of the working fluid in the characteristic points of the hydraulic system and a number of other parameters. The operation of the hydraulic drive of the real manipulation system was simulated and the obtained results were analyzed. The adequacy of simulation results and real physical phenomena observed during the operation of mobile machines is shown. The conjoint movement of two links is a source of increased nonstationarity of hydraulic processes in a throttle-adjustable hydraulic drive
Computer simulation of the general stability loss of the mobile transport and technological machines equipped with boom lift manipulator
The mathematical models and methods of computer modeling of the process of stability loss (overturning) for mobile transport and technological machines equipped with boom lift manipulators are under consideration in this article. This mobile machines are equipped with outriggers, including built-in anchor devices based on piercing the soil of the working elements. The simplest mathematical model, which is a second-order differential equation with respect to the angle of rotation of the system around the center of gravity, allows you to simulate the process of tipping when the manipulator is overloaded, caused by a sharp increase in the load moment or a hurricane gust of wind. However, this model is not informative for practice, as it is more important f to prevent an emergency situation with the rollover of a mobile transport and technological machine than to analyze in advance how it will happen. Therefore, the original model was modified. It’s taking into account the interaction of the anchor device with the ground in the framework of the dynamic system «load – boom lift manipulator – base chassis – outriggers – anchor devices – support ground».
The model takes into account possible variants of initial soil compaction in the area of the outrigger anchor device implementation, which causes a change in its stiffness characteristics used in the simulation. Using proposed in the article approaches performed computer modeling of buckling of the crane Fassi M30A.13, mounted on a truck chassis GAZ-Next
Improving the safety of operation mobile transport and technological machines with manipulators when working with outriggers
A new design of the outriggers for mobile transport and technological machines with manipulators was developed.
A new type of a outrigger allow to increase the overall stability when manipulator is working. The main support com-plemented by an anchoring device for the counteracting for machine overturning and shear service loads. The working element of the anchor device is inserted into the base surface at an angle. This ensures the formation of stress fields be-tween the main support and anchor device. The FEM-simulation confirm the effectiveness of new outrigger design. It is theoretically found that working on the anchor device trying to escape from the base surface. Its front surface is consistently crack the soil by the rotating displacement of its adjacent layers along lines that would lead to the formation of the characteristic buckling of originally flat surface. The main support is counteracting for this process. Thus a sec-ond shear direction (perpendicular to the first direction) is create and significant increase of additional holding moment for 10..40 % (depending on base chassis). If angle between anchor device and base surface is 30...45 degrees the maxi-mum efficiency will be obtained
The effect of topography on the choice of optimal step intermediate supports along the line of the cable metro
In article was formulated and solved the problem of conditional nonlinear optimization of the distance between inter-mediate supports during the design of the cable metro lines in highly urbanized environment, taking into account not the horizontal surface of the terrain. The optimization problem involves a single-criterion objective function that expresses the cost of construction of the cable metro line (total cost of intermediate supports and their foundations, traction and carrying steel cables and technical equipment). The specified objective function subject to minimization by finding the optimal combination of the distance between intermediate supports and tension carrying ropes with accounting con-structive, modal, structural and planning constraints in the form of nonlinear inequalities. When constructing the objec-tive function were considered three possible forms sagging of carrying ropes, which can be implemented for various values of the efforts of their tension. Analysis was done of the influence of the angle of the longitudinal slope of the surface relief along the line of the cable metro on the value of the optimal distance between intermediate supports de-pending on the design and cost of intermediate supports and at the cost of 1 km line of the cable metro. Quantitative calculations showed that with the increase of the longitudinal slope of the surface construction cost also increases with nonlinear increasing rate. The dependence of the cost of 1 km of line underground cable metro from the parameters of the relief is of extreme character with a pronounced minimum at small angles of inclination of the terrain surface about 3...60 degrees. The position of the minimum is quite stable and only slightly changes when enough significant change in the cost of intermediate supports and installed on them technological equipment. The most effective conditions for the construction of the cable metro is the terrain with considerable differences in altitude along the length of the route of transport: only if the surface inclination of more than 50...60 degrees cost of 1 km line starts to exceed the cost of 1 km line laid along a strictly horizontal surface. At small angles of inclination of the surface (less than 6...8 degrees) to min-imize the cost of construction of the cable metro line requires more frequent installation of intermediate supports. How-ever, despite the possibility of building a lower and cheaper supports, the observed increased values of the cost of 1 km of optimum option of the line. At large angles of inclination of the surface a need for a more rare setup higher interme-diate supports. Within the tilt angle 10...60 degrees the range of variation of the optimal step is small enough, amount-ing to no more than ±10 % from the value of the step at an angle of inclination of the surface 10 degree. In the range of small angles of inclination of the terrain surface (3...6 degrees) observed abrupt changes in the basic technical and eco-nomic characteristics of the cable metro lines. This is due to the change of the forms sagging of load-bearing ropes. The increase in the number of supporting ropes has a very small economic effect (within 4 %). It does not change the opti-mal characteristics of such line, as a step of the installation and the height of intermediate supports, shape and sagging boom carrying ropes. However, the significantly reduced diameter of the supporting rope and the horizontal force ten-sion. The increase in aggregate strength of carrying ropes provides a directly proportional increase in the optimal step installation of intermediate supports and leads to a marked decrease in the cost of construction of the cable metro lines. At the height of intermediate supports and the horizontal force of the tension carrying ropes of their aggregate strength influence practically does not, however, leads to a significant reduction in the required diameter of the supporting ropes. It also has a positive effect on reducing the cost characteristics of the construction cable metro line. The capacity of the line cable metro has a significant impact on the optimal values of some of its basic technical and economic characteris-tics, in particular, the cost of 1 km line, the step to install intermediate supports, tension and diameter of the supporting ropes. Its increase is possible by increasing the allowed speed passenger cabins and (or) their capacity and quantity. In all these cases, increasing capacity causes the increase in the cost of 1 km of line and the reduction step of the installa-tion of intermediate supports. The degree of influence these areas of increasing capacity is not the same, which suggests the presence for the given value of the theoretical capacity of an optimal combination of speed, capacity and number of passenger cabins, which will be achieved the greatest technical and economic effect during the construction of the cable metro line
Prospects of introduction of innovative technology overhead passenger traffic on the basis of the passenger ropeways for the modernization of the public transport system of the Bryansk city
In relation to the current situation in the field of public transport in the Bryansk city was shown the main problems in the implementation of innovative technology for the aerial passenger transport on the basis of suspended passenger ropeways (Cable metro). Shows the advantages of the cable metro-based mechatronic technology transportation compared to the traditional suspended passenger ropeways. Was made the technical and economic feasibility analysis of the construction of the cable metro in conditions of a highly urbanized urban environment of large cities, metropolises and urban agglomerations. Presented the statistical data on the development of vehicles in the Bryansk city in the period 2004-2016 years and based on the analysis of these data shows the feasibility of the development of aerial passenger transport as the most high-speed and environmentally friendly mode of transport compared with automobile and electric transport. Considered the possible sources of financing of design and construction works and shows the commercial attractiveness of the project to potential investors in the framework of public-private partnerships. For existing urban development and major transport flows of the Bryansk city was formulated proposals for the location of future transport cable metro lines, order their gaskets, the formation routes of movement of the rolling stock. Made the estimation of labor and financial costs for the implementation of the project of modernization of the public transport system of the city of Bryansk on the basis of the suspended passenger ropeways. The proposed option has the following characteristics: the number of transport lines - 6, total length - 54.8 km, total number of passenger boarding stations - 26, hub passenger stations – 6, the total number of intermediate supports – 100...110 pieces with a span between supports of 400...600 m. the cost of construction of transport lines and the purchase of necessary passenger and processing equipment will be according to rough estimates of 10.6 billion RUB, cost of building passenger stations – 1.9 billion RUB
Optimal design of the cable metro with unified intermediate supports
In article was formulated and solved the problem of conditional nonlinear technical and economic optimization of the distance between intermediate supports, uniform in height, during the design of the cable metro lines in highly urban-ized city environment. The optimization problem involves a single-criterion objective function that expresses the cost of construction of the cable metro line (total cost of intermediate supports and their foundations, traction and carrying steel cables and technical equipment). The specified objective function subject to minimization by finding the optimal combination of the distance between intermediate supports and tension carrying ropes with accounting constructive, modal, structural and planning constraints in the form of nonlinear inequalities. The optimization algorithm was based on the direct method of optimization type, Hooke-Jeeves, which was modified taking into account the need of varying the height of intermediate supports with a constant step equal to the step of unification. When constructing the objective function were considered three possible forms sagging of carrying ropes, which can be implemented for various values of the efforts of their tension. Analysis was done of the influence of the step unification and minimum size of interme-diate supports on their optimum step, the cost of intermediate supports, the cost of 1 km cable metro line for different values of the angle of the longitudinal slope of the surface relief along the cable metro line. The graph of height of uni-fied supports from the angle of the longitudinal slope of the surface relief has discrete-step type. With the increase of the step unify the discreteness increases: the width of the range of angles of the longitudinal slope of the surface relief within which the height of the supports remains constant, increases. The graph of step installation of unified supports along the cable metro line from the angle of the longitudinal slope of the surface relief also has discrete-step type. The transition to a larger height unified intermediate supports determines the need for installation of supports with a large pitch. Its value then begins to decrease monotonically with further increase of the angle of the longitudinal slope of the surface relief until it needs to transition to the new size of supports. Synchronous change in the optimal values of the height and step of the installation of intermediate supports, depending on the angle of the longitudinal slope of the sur-face relief leads to the fact that the optimal cost characteristics of the cable metro lines are smooth functions. It has an extreme character with a minimum at angles of inclination of the surface elevation ~5 degrees, which is associated with the form of sagging of the load-bearing ropes. Unification of intermediate supports has little effect on the optimal cost characteristics of the cable metro lines. Even for a sufficiently large step of the unification the largest difference in op-timal value is almost insignificant: it lies in the range of 2...3%, increasing with increasing the angle of the longitudinal slope of the surface relief and unit cost of the intermediate support. Unification of intermediate supports according to the height and their step practically does not affect the optimal value for horizontal tension on the load-bearing ropes. It determined mainly by the angle of the longitudinal slope of the surface relief. Deviation of horizontal tension on the load-bearing ropes for the nonstandard supports and the unified supports within the range of angles of inclination of the terrain surface 0...60 degrees is not more than 0.5 to 0.8 %
The influence of anchoring of remote supports on the stability of mobile transport and technological machines equipped with boom lift manipulators
The article presents a mathematical model for calculating the characteristics of stability against overturning for mobile transport and technological machines equipped with boom lift manipulators. This model allows us to perform a quantitative assessment of the degree of influence of anchoring of outriggers on the increase of cargo stability of mobile machines during loading and unloading operations. The mathematical model is universal: it allows to estimate efficiency of additional anchoring irrespective of a design of outriggers and placement of anchor devices. On the example of several types of mobile machines shows the effectiveness of outriggers with built-in anchor devices on the basis of piercing working elements. The quantitative analysis of the impact of anchoring on the increase in the weight of the transported cargo and the maximum departure of the handling system and the reducing the width of the support contour of the mobile machine was performed. The analysis of the influence of anchoring on the increase of the maximum allowed angle of inclination of the support surface on which the mobile machine can be operated under the condition of stability against overturning was performed. These positive effects of additional anchoring of outriggers are important in the operations of special mobile machines, in the operations of loading and unloading operations in extreme conditions or during rescue operations in the aftermath of natural and man-made accidents and catastrophes. The formulas for linear two-factor approximation of the main characteristics of cargo stability against overturning of mobile machines depending on the angle of inclination to the horizon of the support countour and the degree of anchoring of outriggers was proposed. The accuracy of the approximation is maximum within 10%. The proposed recommendations for the rational choice of approximation points can significantly improve its accuracy for specific operating conditions of mobile transport and technological machines
The study of dynamics and strength of hydraulic crane-manipulating installations on a movable chassis
The modified version of previously reviewed technique for dynamics and stress analysis of fixed-base manipulators (articulating cranes) is suggested. The idea is to insert a fictitious six-degrees-of-freedom joint between a fixed support and manipulator’s base thus eliminating fixed base motion constraints. The technique has been implemented in the software package KBCrane and used for dynamics and stress analysis of an articulating crane mounted on a ship rocking in waves. Based on the results of simulation the distribution and level of stress in the crane is estimated
Effectiveness of elastic damping in the pivot joints of cargo boom of crane-manipulating installations at large gaps
The article was the analysis of dynamic processes in the cylindrical hinges with large gaps in the cargo boom crane-manipulating installations of mobile machines in operation. Consider the design of damping device for articulated joints, which creates a braking force of elastic resistance to the displacement of the hinge pin within the large gap. The mechanism of action of the damping devices was considered. Analysis of the effectiveness of damping device for re-ducing the dynamic stress state in the elements of cargo boom metal structures depending on the gap size and the stiff-ness of the damping device was performed. Damping device with an elastic shock absorbing elements substantially reduces the additional impact load at the time of selection of the gap in the joint, slow the growth of clearance in the pivot joint, limit the size of the gap specified value, which must not be exceeded during the entire service life of swivel independently from the intensity of his load