Andrzej Maczynski - Academia.edu (original) (raw)

Papers by Andrzej Maczynski

Transport and Telecommunication Journal

In many road safety, traffic management, and travel planning analyses, it is useful to classify r... more In many road safety, traffic management, and travel planning analyses, it is useful to classify road sections according to risk level. Such classification is labour-intensive and needs to be reviewed periodically. The authors propose a model for identifying a discrete risk class for road sections based on selected traffic flow parameters, which are available in most measurement systems monitoring current traffic conditions. The Surrogate Safety Measures approach was applied in the model formulated using Principal Components Analysis. As input to the model SSMs are used in the form of a set of hourly average traffic flow parameters. The SSMs used are: the percentage of light vehicles exceeding the speed limit by a value in the range 21 to 30 km/h; the percentage of light vehicles exceeding the speed limit by more than 30 km/h; the traffic volume of light vehicles; the traffic volume of heavy vehicles and the mean speeds of light vehicles and heavy vehicles. This paper presents result...

Transport and Telecommunication Journal, 2021

Speed is a crucial factor in the frequency and severity of road accidents. Light and heavy vehicl... more Speed is a crucial factor in the frequency and severity of road accidents. Light and heavy vehicles speed in free-flow traffic at six locations on Poland’s national road network was analyzed. The results were used to formulate two models predicting the mean speed in free-flow traffic for both light and heavy vehicles. The first one is a multiple linear regression model, the second is based on an artificial neural network with a radial type of neuron function. A set of the following input parameters is used: average hourly traffic, the percentage of vehicles in free-flow traffic, geometric parameters of the road section (lane and hard shoulder width), type of day and time (hour). The ANN model was found to be more effective for predicting the mean free-flow speed of vehicles. Assuming a 5% acceptable error of indication, the ANN model predicted the mean free-flow speed correctly in 84% of cases for light and 89% for heavy vehicles.

Energies, 2021

The challenge of maintaining the required level of mobility and air quality in cities can be met ... more The challenge of maintaining the required level of mobility and air quality in cities can be met by deploying an appropriate management system in which the immediate vicinity of roads is monitored to identify potential pollution hotspots. This paper presents an integrated low-cost system which can be used to study the impact of traffic related emission on air quality at intersections. The system was used for three months in 2017 at five locations covering intersections in the centre of a mid-sized city. Depending on the location, pollution hotspots with high PM2.5 and PM10 concentrations occurred 5–10% of the time. It was shown that despite the close mutual proximity of the locations, traffic and the immediate surroundings lead to significant variation in air quality. At locations with adverse ventilation conditions a tendency towards more frequent occurrences of moderate and sufficient air quality was observed than at other locations (even those with more traffic). Based on the res...

Sensors, 2021

This paper presents the analyses of the signals recorded by the main sensors of a WIM test statio... more This paper presents the analyses of the signals recorded by the main sensors of a WIM test station in the cases of abnormal runs (i.e., runs with the changes of trajectory or the dynamics of vehicle motion). The research involved strain gauges which are used for measuring the weight of vehicles, inductive loops, as well as piezoelectric sensors used, inter alia, to detect twin wheels and to determine where a vehicle passes through a station. Since the designers intend the station to be able to implement the direct enforcement function, the selection of runs deviating from the normative ones constitutes an important issue for the assessment of the measurement reliability. The study considered the location of the trajectory of the runs, the dynamics (acceleration/braking) and the trajectory changes. The change in the amplitude and the value of the signal recorded by the strain gauges as a function of the location (position) of the contact between sensor and tires is a noteworthy obser...

Communications in Computer and Information Science, 2015

This article presents the assumptions and results of research aimed at comparing the radar system... more This article presents the assumptions and results of research aimed at comparing the radar systems and video detection devices. The experiment was conducted on a multilane road section, outside the built-up area. The paper compares the effectiveness of traffic volume detection and vehicle classification. Presented analyses describe the variability in terms of vehicle intensity and as a function of weather conditions.

Ocean Engineering & Oceanography, 2013

This book describes new methods developed for modelling dynamics of machines commonly used in the... more This book describes new methods developed for modelling dynamics of machines commonly used in the offshore industry. These methods are based both on the rigid finite element method, used for the description of link deformations, and on homogeneous transformations and joint coordinates, which is applied to the modelling of multibody system dynamics. In this monograph, the bases of the rigid finite element method and homogeneous transformations are introduced. Selected models for modelling dynamics of offshore devices are then verified both by using commercial software, based on the finite element method, as well as by using additional methods. Examples of mathematical models of offshore machines, such as a gantry crane for Blowout-Preventer (BOP) valve block transportation, a pedestal crane with shock absorber, and pipe laying machinery are presented. Selected problems of control in offshore machinery as well as dynamic optimization in device control are also discussed. Additionally, numerical simulations of pipe-laying operations taking active reel drive into account are shown.

In the paper the 3-D model of a telescopic mobile crane is presented. In the model flexibilities ... more In the paper the 3-D model of a telescopic mobile crane is presented. In the model flexibilities and damping have been taken into account and also the number of degrees of freedom can be chosen according to the complexity of an approach. The algorithm of optimisation of drive functions for the slewing upper structure is given. The main goal of optimisation was to ensure load positioning at the end point of a work cycle in the case when oscillations are minimal. In order to achieve appropriate numerical effectiveness, the optimisation problem was solved for the simple, fully rigid model of a mobile crane. The method of compensating neglected flexibilities of the base structure of the crane and inner disturbances connected with the feedback control system via digital PID controller is presented.

Open Engineering, 2020

Overloaded vehicles pose a real threat to road safety and significantly contribute to the degrada... more Overloaded vehicles pose a real threat to road safety and significantly contribute to the degradation of the road surface. High-Speed Weigh in Motion (HS-WIM) stations are the commonly used method of eliminating them from traffic. In Poland, HS-WIM stations operate in pre-selection mode, sending information to services about the potential exceedance of acceptable standards by a specific vehicle. The article presents the results of the data analysis from selected HS-WIM stations operating on the national road network in Poland indicating significant limitations of the effectiveness of the whole system. The main reason for this may be that carriers use the knowledge about the HS-WIM stations location and working time to avoid inspections. The results presented in the paper indicate, among other things, that in some locations the share of vehicles overloaded with traffic increases significantly outside the working hours of the controlling services. For Light Commercial Vehicle, the sha...

In the paper, a method of final positioning of a load in slewing motion for jib cranes is propose... more In the paper, a method of final positioning of a load in slewing motion for jib cranes is proposed. The method is based on the so called ”map of basic functions”. The map stores drive functions of jib slewing motion for particular slew angles chosen so that they form a kind of base. The basic functions are determined for certain operational parameters (angle of jib slew, time of slewing, crane radius, mass of the load, length of the rope, etc.) using optimisation methods. Drive functions for different parameters, particularly for different slew angles, are calculated by a crane control system directly before slewing. Linear interpolation is used for this task. The method proposed has been experimentally verified using a physical model of a jib crane. Key words: crane, positioning, experimental investigation 1.

Journal of Theoretical and Applied Mechanics, 2003

In the paper a method of load positioning and minimization of load final oscillations in rotary c... more In the paper a method of load positioning and minimization of load final oscillations in rotary cranes has been presented. Drive functions of the slewing of an upper structure have been determined by means of dynamic optimisation. In the optimisation task a simplified model has been used. A completely stiff supporting structure of the crane has been assumed. A feedback control system has been proposed to compensate for influences of flexibilities that have not been taken into account during the optimisation and for inaccurate knowledge of parameters of the model. The effectiveness of the control system for two different controlled variables has been analysed. A special coefficient for quantitative analysis has been proposed. Results of numerical simulations have been presented.

Journal of Theoretical and Applied Mechanics, 2008

In the paper, a method of final positioning of a load in slewing motion for jib cranes is propose... more In the paper, a method of final positioning of a load in slewing motion for jib cranes is proposed. The method is based on the so called "map of basic functions". The map stores drive functions of jib slewing motion for particular slew angles chosen so that they form a kind of base. The basic functions are determined for certain operational parameters (angle of jib slew, time of slewing, crane radius, mass of the load, length of the rope, etc.) using optimisation methods. Drive functions for different parameters, particularly for different slew angles, are calculated by a crane control system directly before slewing. Linear interpolation is used for this task. The method proposed has been experimentally verified using a physical model of a jib crane.

Journal of Theoretical and Applied Mechanics, 2010

In the paper, mathematical models for dynamic analysis of a BOP crane under sea weaving condition... more In the paper, mathematical models for dynamic analysis of a BOP crane under sea weaving conditions are presented. The BOP crane is a kind of gantry crane. It is installed on drilling platforms and used for transportation of the Blowout Preventor (BOP). The most important features characterising its dynamics are: motion of the crane base caused by sea weaving, clearance in the supporting system (between the support and rails), impacts of the load into guides and a significant weight of the load. In order to investigate dynamics of the system, its mathematical model taking into consideration all these features has been formulated. Equations of motions have been derived using homogenous transformations. In order to improve numerical effectiveness of the model, the equations have been transformed to an explicit form. The input in the drive of the travel system has been modelled in two ways: the kinematic input via a spring-damping element and the force input. Exemplary results of numeri...

The monograph deals with selected issues associated with steering of working movements of the jib... more The monograph deals with selected issues associated with steering of working movements of the jib cranes. Three methods of final positioning of the cargo crane in the slewing of the upper structure have been proposed. They vary not only with the algorithm and the structure of the control system but also with the required measurement equipment. In case of cranes founded on the moveable base, in particular the offshore cranes, the problem of stabilization of the cargo position is important. A way to solve this problem is presented in the book. It assumes the simultaneous use of drives: drum winch and special auxiliary system. The work contains description of the crane models: the basic one, taking into account flexibilities and damping in the selected subsystems, its modifications and simplified models used in the optimization tasks. The results of the indirect verification of the basic model are also presented. A physical model of the rotary crane has been used, to carry out experime...

Communications in Computer and Information Science, 2016

In the article, the authors presented preliminary concept for an information system on road condi... more In the article, the authors presented preliminary concept for an information system on road conditions in the city’s transport network, which also makes it possible to carry out short-term weather prediction to provide users with early warning of impending deterioration of traffic conditions. The system consists of three layers: the measuring, computing and information. In this paper, the authors are especially focused on the first layer, which is a fundamental part of the system.

Archive of Mechanical Engineering, 2013

In offshore pedestal cranes one may distinguish three components of considerable length: a pedest... more In offshore pedestal cranes one may distinguish three components of considerable length: a pedestal, a boom and a frame present in some designs. It is often necessary in dynamical analyses to take into account their flexibility. A convenient and efficient method for modelling them is the rigid finite element method in a modified form. The rigid finite element method allows us to take into account the flexibility of the beam system in selected directions while introducing a relatively small number of additional degrees of freedom to the system. This paper presents a method for modelling the pedestal, the frame and the boom of an offshore column crane, treating each of these components in a slightly different way. A custom approach is applied to the pedestal, using rigid finite elements of variable length. Results of sample numeric computations are included.

Offshore pedestal cranes are devices installed on offshore platforms or vessels. A characteri-sti... more Offshore pedestal cranes are devices installed on offshore platforms or vessels. A characteri-stic feature of any floating object is the significant movement caused by sea waving. These movements cause that the offshore cranes are exposed to dynamic loads reasonably higher than structures of similar operational parameters but operated on land. Therefore, they are equipped with special systems for overload reduction. One of them is the shock absorber. The paper presents a mathematical model of an offshore pedestal crane with a shock absor-ber. Results of numerical simulations are presented to assess the effectiveness of the shock absorber in conditions when large dynamic overloads occur. Key words: modelling, offshore crane, shock absorber 1.

Nonlinear Dynamics, 2003

In the paper the 3-D model of a telescopic mobile crane is presented. In the model flexibilities ... more In the paper the 3-D model of a telescopic mobile crane is presented. In the model flexibilities and damping have been taken into account and also the number of degrees of freedom can be chosen according to the complexity of an approach. The algorithm of optimisation of drive functions for the slewing upper structure is given. The main goal of optimisation was to ensure load positioning at the end point of a work cycle in the case when oscillations are minimal. In order to achieve appropriate numerical effectiveness, the optimisation problem was solved for the simple, fully rigid model of a mobile crane. The method of compensating neglected flexibilities of the base structure of the crane and inner disturbances connected with the feedback control system via digital PID controller is presented.

AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe

The article presents the results of road tests related to repeatability evaluation of the mobile ... more The article presents the results of road tests related to repeatability evaluation of the mobile road weather sensor readings. This kind of sensors is increasingly used by road administrators to assess current state of roads. They can be also used to identify road sections where local changes in friction occur most often. The carried out tests concern the repeatability of readings for different lighting conditions (day and night) and vehicle speed. The research was performed using the Lufft MARWIS sensor on roads with different traffic intensity and different standards of winter maintenance.

Journal of Theoretical and Applied Mechanics, 2012

Offshore pedestal cranes are devices installed on offshore platforms or vessels. A characteristic... more Offshore pedestal cranes are devices installed on offshore platforms or vessels. A characteristic feature of any floating object is the significant movement caused by sea waving. These movements cause that the offshore cranes are exposed to dynamic loads reasonably higher than structures of similar operational parameters but operated on land. Therefore, they are equipped with special systems for overload reduction. One of them is the shock absorber. The paper presents a mathematical model of an offshore pedestal crane with a shock absorber. Results of numerical simulations are presented to assess the effectiveness of the shock absorber in conditions when large dynamic overloads occur.

Przegląd Mechaniczny, 2004

Transport and Telecommunication Journal

In many road safety, traffic management, and travel planning analyses, it is useful to classify r... more In many road safety, traffic management, and travel planning analyses, it is useful to classify road sections according to risk level. Such classification is labour-intensive and needs to be reviewed periodically. The authors propose a model for identifying a discrete risk class for road sections based on selected traffic flow parameters, which are available in most measurement systems monitoring current traffic conditions. The Surrogate Safety Measures approach was applied in the model formulated using Principal Components Analysis. As input to the model SSMs are used in the form of a set of hourly average traffic flow parameters. The SSMs used are: the percentage of light vehicles exceeding the speed limit by a value in the range 21 to 30 km/h; the percentage of light vehicles exceeding the speed limit by more than 30 km/h; the traffic volume of light vehicles; the traffic volume of heavy vehicles and the mean speeds of light vehicles and heavy vehicles. This paper presents result...

Transport and Telecommunication Journal, 2021

Speed is a crucial factor in the frequency and severity of road accidents. Light and heavy vehicl... more Speed is a crucial factor in the frequency and severity of road accidents. Light and heavy vehicles speed in free-flow traffic at six locations on Poland’s national road network was analyzed. The results were used to formulate two models predicting the mean speed in free-flow traffic for both light and heavy vehicles. The first one is a multiple linear regression model, the second is based on an artificial neural network with a radial type of neuron function. A set of the following input parameters is used: average hourly traffic, the percentage of vehicles in free-flow traffic, geometric parameters of the road section (lane and hard shoulder width), type of day and time (hour). The ANN model was found to be more effective for predicting the mean free-flow speed of vehicles. Assuming a 5% acceptable error of indication, the ANN model predicted the mean free-flow speed correctly in 84% of cases for light and 89% for heavy vehicles.

Energies, 2021

The challenge of maintaining the required level of mobility and air quality in cities can be met ... more The challenge of maintaining the required level of mobility and air quality in cities can be met by deploying an appropriate management system in which the immediate vicinity of roads is monitored to identify potential pollution hotspots. This paper presents an integrated low-cost system which can be used to study the impact of traffic related emission on air quality at intersections. The system was used for three months in 2017 at five locations covering intersections in the centre of a mid-sized city. Depending on the location, pollution hotspots with high PM2.5 and PM10 concentrations occurred 5–10% of the time. It was shown that despite the close mutual proximity of the locations, traffic and the immediate surroundings lead to significant variation in air quality. At locations with adverse ventilation conditions a tendency towards more frequent occurrences of moderate and sufficient air quality was observed than at other locations (even those with more traffic). Based on the res...

Sensors, 2021

This paper presents the analyses of the signals recorded by the main sensors of a WIM test statio... more This paper presents the analyses of the signals recorded by the main sensors of a WIM test station in the cases of abnormal runs (i.e., runs with the changes of trajectory or the dynamics of vehicle motion). The research involved strain gauges which are used for measuring the weight of vehicles, inductive loops, as well as piezoelectric sensors used, inter alia, to detect twin wheels and to determine where a vehicle passes through a station. Since the designers intend the station to be able to implement the direct enforcement function, the selection of runs deviating from the normative ones constitutes an important issue for the assessment of the measurement reliability. The study considered the location of the trajectory of the runs, the dynamics (acceleration/braking) and the trajectory changes. The change in the amplitude and the value of the signal recorded by the strain gauges as a function of the location (position) of the contact between sensor and tires is a noteworthy obser...

Communications in Computer and Information Science, 2015

This article presents the assumptions and results of research aimed at comparing the radar system... more This article presents the assumptions and results of research aimed at comparing the radar systems and video detection devices. The experiment was conducted on a multilane road section, outside the built-up area. The paper compares the effectiveness of traffic volume detection and vehicle classification. Presented analyses describe the variability in terms of vehicle intensity and as a function of weather conditions.

Ocean Engineering & Oceanography, 2013

This book describes new methods developed for modelling dynamics of machines commonly used in the... more This book describes new methods developed for modelling dynamics of machines commonly used in the offshore industry. These methods are based both on the rigid finite element method, used for the description of link deformations, and on homogeneous transformations and joint coordinates, which is applied to the modelling of multibody system dynamics. In this monograph, the bases of the rigid finite element method and homogeneous transformations are introduced. Selected models for modelling dynamics of offshore devices are then verified both by using commercial software, based on the finite element method, as well as by using additional methods. Examples of mathematical models of offshore machines, such as a gantry crane for Blowout-Preventer (BOP) valve block transportation, a pedestal crane with shock absorber, and pipe laying machinery are presented. Selected problems of control in offshore machinery as well as dynamic optimization in device control are also discussed. Additionally, numerical simulations of pipe-laying operations taking active reel drive into account are shown.

In the paper the 3-D model of a telescopic mobile crane is presented. In the model flexibilities ... more In the paper the 3-D model of a telescopic mobile crane is presented. In the model flexibilities and damping have been taken into account and also the number of degrees of freedom can be chosen according to the complexity of an approach. The algorithm of optimisation of drive functions for the slewing upper structure is given. The main goal of optimisation was to ensure load positioning at the end point of a work cycle in the case when oscillations are minimal. In order to achieve appropriate numerical effectiveness, the optimisation problem was solved for the simple, fully rigid model of a mobile crane. The method of compensating neglected flexibilities of the base structure of the crane and inner disturbances connected with the feedback control system via digital PID controller is presented.

Open Engineering, 2020

Overloaded vehicles pose a real threat to road safety and significantly contribute to the degrada... more Overloaded vehicles pose a real threat to road safety and significantly contribute to the degradation of the road surface. High-Speed Weigh in Motion (HS-WIM) stations are the commonly used method of eliminating them from traffic. In Poland, HS-WIM stations operate in pre-selection mode, sending information to services about the potential exceedance of acceptable standards by a specific vehicle. The article presents the results of the data analysis from selected HS-WIM stations operating on the national road network in Poland indicating significant limitations of the effectiveness of the whole system. The main reason for this may be that carriers use the knowledge about the HS-WIM stations location and working time to avoid inspections. The results presented in the paper indicate, among other things, that in some locations the share of vehicles overloaded with traffic increases significantly outside the working hours of the controlling services. For Light Commercial Vehicle, the sha...

In the paper, a method of final positioning of a load in slewing motion for jib cranes is propose... more In the paper, a method of final positioning of a load in slewing motion for jib cranes is proposed. The method is based on the so called ”map of basic functions”. The map stores drive functions of jib slewing motion for particular slew angles chosen so that they form a kind of base. The basic functions are determined for certain operational parameters (angle of jib slew, time of slewing, crane radius, mass of the load, length of the rope, etc.) using optimisation methods. Drive functions for different parameters, particularly for different slew angles, are calculated by a crane control system directly before slewing. Linear interpolation is used for this task. The method proposed has been experimentally verified using a physical model of a jib crane. Key words: crane, positioning, experimental investigation 1.

Journal of Theoretical and Applied Mechanics, 2003

In the paper a method of load positioning and minimization of load final oscillations in rotary c... more In the paper a method of load positioning and minimization of load final oscillations in rotary cranes has been presented. Drive functions of the slewing of an upper structure have been determined by means of dynamic optimisation. In the optimisation task a simplified model has been used. A completely stiff supporting structure of the crane has been assumed. A feedback control system has been proposed to compensate for influences of flexibilities that have not been taken into account during the optimisation and for inaccurate knowledge of parameters of the model. The effectiveness of the control system for two different controlled variables has been analysed. A special coefficient for quantitative analysis has been proposed. Results of numerical simulations have been presented.

Journal of Theoretical and Applied Mechanics, 2008

In the paper, a method of final positioning of a load in slewing motion for jib cranes is propose... more In the paper, a method of final positioning of a load in slewing motion for jib cranes is proposed. The method is based on the so called "map of basic functions". The map stores drive functions of jib slewing motion for particular slew angles chosen so that they form a kind of base. The basic functions are determined for certain operational parameters (angle of jib slew, time of slewing, crane radius, mass of the load, length of the rope, etc.) using optimisation methods. Drive functions for different parameters, particularly for different slew angles, are calculated by a crane control system directly before slewing. Linear interpolation is used for this task. The method proposed has been experimentally verified using a physical model of a jib crane.

Journal of Theoretical and Applied Mechanics, 2010

In the paper, mathematical models for dynamic analysis of a BOP crane under sea weaving condition... more In the paper, mathematical models for dynamic analysis of a BOP crane under sea weaving conditions are presented. The BOP crane is a kind of gantry crane. It is installed on drilling platforms and used for transportation of the Blowout Preventor (BOP). The most important features characterising its dynamics are: motion of the crane base caused by sea weaving, clearance in the supporting system (between the support and rails), impacts of the load into guides and a significant weight of the load. In order to investigate dynamics of the system, its mathematical model taking into consideration all these features has been formulated. Equations of motions have been derived using homogenous transformations. In order to improve numerical effectiveness of the model, the equations have been transformed to an explicit form. The input in the drive of the travel system has been modelled in two ways: the kinematic input via a spring-damping element and the force input. Exemplary results of numeri...

The monograph deals with selected issues associated with steering of working movements of the jib... more The monograph deals with selected issues associated with steering of working movements of the jib cranes. Three methods of final positioning of the cargo crane in the slewing of the upper structure have been proposed. They vary not only with the algorithm and the structure of the control system but also with the required measurement equipment. In case of cranes founded on the moveable base, in particular the offshore cranes, the problem of stabilization of the cargo position is important. A way to solve this problem is presented in the book. It assumes the simultaneous use of drives: drum winch and special auxiliary system. The work contains description of the crane models: the basic one, taking into account flexibilities and damping in the selected subsystems, its modifications and simplified models used in the optimization tasks. The results of the indirect verification of the basic model are also presented. A physical model of the rotary crane has been used, to carry out experime...

Communications in Computer and Information Science, 2016

In the article, the authors presented preliminary concept for an information system on road condi... more In the article, the authors presented preliminary concept for an information system on road conditions in the city’s transport network, which also makes it possible to carry out short-term weather prediction to provide users with early warning of impending deterioration of traffic conditions. The system consists of three layers: the measuring, computing and information. In this paper, the authors are especially focused on the first layer, which is a fundamental part of the system.

Archive of Mechanical Engineering, 2013

In offshore pedestal cranes one may distinguish three components of considerable length: a pedest... more In offshore pedestal cranes one may distinguish three components of considerable length: a pedestal, a boom and a frame present in some designs. It is often necessary in dynamical analyses to take into account their flexibility. A convenient and efficient method for modelling them is the rigid finite element method in a modified form. The rigid finite element method allows us to take into account the flexibility of the beam system in selected directions while introducing a relatively small number of additional degrees of freedom to the system. This paper presents a method for modelling the pedestal, the frame and the boom of an offshore column crane, treating each of these components in a slightly different way. A custom approach is applied to the pedestal, using rigid finite elements of variable length. Results of sample numeric computations are included.

Offshore pedestal cranes are devices installed on offshore platforms or vessels. A characteri-sti... more Offshore pedestal cranes are devices installed on offshore platforms or vessels. A characteri-stic feature of any floating object is the significant movement caused by sea waving. These movements cause that the offshore cranes are exposed to dynamic loads reasonably higher than structures of similar operational parameters but operated on land. Therefore, they are equipped with special systems for overload reduction. One of them is the shock absorber. The paper presents a mathematical model of an offshore pedestal crane with a shock absor-ber. Results of numerical simulations are presented to assess the effectiveness of the shock absorber in conditions when large dynamic overloads occur. Key words: modelling, offshore crane, shock absorber 1.

Nonlinear Dynamics, 2003

In the paper the 3-D model of a telescopic mobile crane is presented. In the model flexibilities ... more In the paper the 3-D model of a telescopic mobile crane is presented. In the model flexibilities and damping have been taken into account and also the number of degrees of freedom can be chosen according to the complexity of an approach. The algorithm of optimisation of drive functions for the slewing upper structure is given. The main goal of optimisation was to ensure load positioning at the end point of a work cycle in the case when oscillations are minimal. In order to achieve appropriate numerical effectiveness, the optimisation problem was solved for the simple, fully rigid model of a mobile crane. The method of compensating neglected flexibilities of the base structure of the crane and inner disturbances connected with the feedback control system via digital PID controller is presented.

AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe

The article presents the results of road tests related to repeatability evaluation of the mobile ... more The article presents the results of road tests related to repeatability evaluation of the mobile road weather sensor readings. This kind of sensors is increasingly used by road administrators to assess current state of roads. They can be also used to identify road sections where local changes in friction occur most often. The carried out tests concern the repeatability of readings for different lighting conditions (day and night) and vehicle speed. The research was performed using the Lufft MARWIS sensor on roads with different traffic intensity and different standards of winter maintenance.

Journal of Theoretical and Applied Mechanics, 2012

Offshore pedestal cranes are devices installed on offshore platforms or vessels. A characteristic... more Offshore pedestal cranes are devices installed on offshore platforms or vessels. A characteristic feature of any floating object is the significant movement caused by sea waving. These movements cause that the offshore cranes are exposed to dynamic loads reasonably higher than structures of similar operational parameters but operated on land. Therefore, they are equipped with special systems for overload reduction. One of them is the shock absorber. The paper presents a mathematical model of an offshore pedestal crane with a shock absorber. Results of numerical simulations are presented to assess the effectiveness of the shock absorber in conditions when large dynamic overloads occur.

Przegląd Mechaniczny, 2004