Overhead crane anti-swing system based on the Pontryagin’s maximum principle

Overhead cranes are widely used at industrial enterprises for transportation of materials and products. They are successfully adaptable to technological processes used at an enterprise and their exploitation is inexpensive; in addition, the price of cranes is relatively low. However, extension of requirements set for technological processes results in shortened time for transportation and stiffened requirements for accuracy of cargo delivery and cargo safety. In the attempts to satisfy the latter requirements, particular attention is paid to swings of the cargo-holding rope. There is a number of factors that cause increased requirements for the control system of the crane drive. The slewing movement affects the total system of the crane and aggravates the crane movement control. In modern overhead cranes, the abilities and qualification of an operator (who is assisted by a certain anti-swing system) predetermine the cargo swings and the accuracy of its positioning. The said circumstance latterly caused a particular attention to computerisation of overhead crane control. However, a nonlinearity of the mechanical system of a crane and complicated control of swings often cause undesirable swings, in particular in the beginning and the end of cargo transporting process, thus reducing the efficiency of usual crane control systems. In addition, it should be taken into account that the parameters of a crane, as a controlled mechanical system, depend on the cargo and the conditions of its transportation. Consequently, a development of an effective cargo swing reduction system is a currently topical engineering problem

Dynamic reaction forces of an overhead crane on lifting

In the recent period, girder bridge cranes are replaced with double-beam overhead cranes with a rectangular cross-section of the beams. In addition, new materials are used for producing them thus applying other values of allowable loads and deformations. The paper focuses on two overhead cranes working for JSC Vilniaus kranai (Vilnius Cranes). The presented mathematical model provides an opportunity to assess the structural peculiarities of the above introduced cranes. The calculated results of dynamic loads appearing in the beginning and the end of the lifting process and having an impact on the lifting mechanism and metal structure are provided in the article

Skysčių mechanika. Hidraulinių ir pneumatinių sistemų elementai ir pavaros

Mokomoji knyga skiriama universitetų technikos fakultetų dieninio, vakarinio ir neakivaizdinio skyriaus studentams, studijuojantiems skysčių mechanikos ir hidraulinių sistemų disciplinas. Ja taip pat galės naudotis aukštesniųjų technikos mokyklų studentai, nagrinėjantys ir baigiamuosiuose darbuose taikantys hidraulines sistemas arba jų elementus. Leidinys parengtas ir išleistas už Europos struktūrinių fondų lėšas, jomis finansuojant VGTU Transporto inžinerijos, Biomechanikos ir Aviacinės mechanikos inžinerijos projektą „Studijų programų atnaujinimas pagal ES reikalavimus, gerinant studijų kokybę ir taikant inovatyvius studijų metodus“ pagal Lietuvos 2007–2013 m. Žmogiškųjų išteklių veiksmų programos 2 prioriteto „Mokymasis visą gyvenimą“ VP1-2.2-ŠMM-07-K priemonę „Studijų kokybės gerinimas, tarptautiškumo didinimas“. Projekto kodas Nr. VP1-2.2-ŠMM 07-K-01-023, finansavimo ir administravimo sutartis Nr. VP1-2.2-ŠMM-07-K-01-023

Krovos darbų mašinos. Konvejeriai

Mokmoji knyga skiriama universitetų techniškųjų fakultetų dieninio, vakarinio ir neakivaizdinio skyriaus studentams, studijuojantiems krovos darbų mašinas. Ja taip pat gali naudotis aukštesniųjų technikos mokyklų studentai, nagrinėjantys krovos darbų bei krovinių mechanizuoto bei automatizuoto transportavimo darbus krovinių terminaluose bei gamybos procese. Leidinys parengtas ir išleistas už Europos struktūrinių fondų lėšas, jomis finansuojant VGTU Transporto inžinerijos, Biomechanikos ir Aviacinės mechanikos inžinerijos projektą „Studijų programų atnaujinimas pagal ES reikalavimus, gerinant studijų kokybę ir taikant inovatyvius studijų metodus“ pagal Lietuvos 2007–2013 m. Žmogiškųjų išteklių veiksmų programos 2 prioriteto „Mokymasis visą gyvenimą“ VP1-2.2-ŠMM-07-K priemonę „Studijų kokybės gerinimas, tarptautiškumo didinimas“. Projekto kodas Nr. VP1-2.2-ŠMM 07-K-01-023, finansavimo ir administravimo sutartis Nr. VP1-2.2-ŠMM-07-K-01-023

Research of the efficiency of use of shock absorbers with controlled dissipative force in motor cars

Shock absorbers are chosen according to a certain average influence, so in a wider range of an influence of vibrations as well as on changes of the weight of the transported cargo a scantiness of ordinary shock absorbers comes to light. In the article, possibilities of an application of a shock absorber with magnetic liquid are discussed. In such case, dissipative features may be changed dependently on the level on vibrations of the amortized object. For this purpose, a feedback receiving signals from a seismic sensor is used.[...]

The investigation of vibro-isolating features of transmissions of vehicles in elastic centrifugal couplings using the method of identification of dynamic processes in half-couplings on the universal dynamic test stand

The presented paper describes the investigation of vibro-isolating features of transmissions of vehicles using universal dynamic test stand. The stand is protected by copyright and distinguishes itself for many advantages in comparison with the existing stands: it is contactless, precise in a wide frequency range, power-saving, high-speed. Due to low exploitation expenses and wide possibilities it is fit for the investigation of dynamic characteristics of various vehicles. On the said stand using the method of the identification of experiment dynamic processes, the investigation of vibroisolating features of rotor systems has been performed. The errors caused by the unevenness of rotation of connecting shafts, the adequacy of the calculated models and the dangerous resonance frequencies have been determined. First Published Online: 19 Dec 201

Transporto priemonių movos su keičiamomis charakteristikomis

Couplings abruptly changing their torsional rigidity and carrying capacity when the transmitted torque reaches a particular value are considered. This state is achieved either changing the conditions of the deformation of a flexible member or by excluding it from torque transmission. In the presented paper the conditions of mode variation are determined and some relationships for determining major parameters of couplings are given.Lietuviška santrauka. Nagrinėjamos movos, kurių sukamasis standis ir apkrovos kinta šuoliškai priklausomai nuo perduodamo sukamojo momento reikšmės. Movomis perduodant sukamąjį momentą, pavaros darbo tolygumą galima užtikrinti keičiant tampraus elemento judesio deformavimo sąlygas arba visai eliminuojant jį iš sukamojo momento perdavimo proceso. Nustatytos movos sukamojo judesio perdavimo proceso iš vieno režimą į kitą sąlygos, pateikiamos movos pagrindinių parametrų nustatymo matematinės formulės

Pipeline robots with elastic elements

In the article constructions of the pipeline robots with elastic elements are reviewed and the scheme of new original construction is presented. The mathematical models of a robot with one-dimensional vibration exciter with two degrees of freedom were developed and the equations of movement were formed and written. The mathematical model of the pipeline robot with circular elements is formed and its motion equations are presented. First Published Online: 19 Dec 201

Vibration isolating couplings for operation in various excitation

The paper considers couplings of variable torsional rigidity and carrying capacity which varies depending on loading. Couplings are tested under varying deformation conditions of flexible element and when some additional supports are introduced. Two types of couplings having ring- and arch-shaped flexible elements are considered. Coupling performance under changing conditions is described. The couplings analysed are used in the systems of mechanical transmision

Development of pipe crawling robots with vibratory drives and investigation of their kinematic parameters

In the article the classification of pipe crawling robots with vibratory drives is presented, their advantages and imperfections are reviewed. The schemes of the construction of a pipe crawling robot with a vibratory impulse drive and a pipe crawling robot with a vibratory pneumatic drive are discussed. The dynamic models of a robot with a vibratory impulse drive and of a robot with a vibratory pneumatic drive were developed and the equations of their movement were formed and written. First Published Online: 19 Dec 201