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Volume 26 (2021): Issue 3 (September 2021)

Volume 26 (2021): Issue 2 (June 2021)

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Volume 25 (2020): Issue 4 (December 2020)

Volume 25 (2020): Issue 3 (September 2020)

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Volume 24 (2019): Issue 4 (December 2019)

Volume 24 (2019): Issue 3 (September 2019)

Volume 24 (2019): Issue 2 (June 2019)

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Volume 23 (2018): Issue 4 (November 2018)

Volume 23 (2018): Issue 3 (August 2018)

Volume 23 (2018): Issue 2 (May 2018)

Volume 23 (2018): Issue 1 (February 2018)

Volume 22 (2017): Issue 4 (December 2017)

Volume 22 (2017): Issue 3 (August 2017)

Volume 22 (2017): Issue 2 (May 2017)

Volume 22 (2017): Issue 1 (February 2017)

Volume 21 (2016): Issue 4 (December 2016)

Volume 21 (2016): Issue 3 (August 2016)

Volume 21 (2016): Issue 2 (May 2016)

Volume 21 (2016): Issue 1 (February 2016)

Volume 20 (2015): Issue 4 (December 2015)

Volume 20 (2015): Issue 3 (August 2015)

Volume 20 (2015): Issue 2 (May 2015)

Volume 20 (2015): Issue 1 (February 2015)

Volume 19 (2014): Issue 4 (December 2014)

Volume 19 (2014): Issue 3 (August 2014)

Volume 19 (2014): Issue 2 (May 2014)

Volume 19 (2014): Issue 1 (February 2014)

Volume 18 (2013): Issue 4 (December 2013)

Volume 18 (2013): Issue 3 (August 2013)

Volume 18 (2013): Issue 2 (June 2013)

Volume 18 (2013): Issue 1 (March 2013)

Journal Details
Format
Journal
eISSN
2353-9003
First Published
19 Apr 2013
Publication timeframe
4 times per year
Languages
English

Search

Volume 19 (2014): Issue 3 (August 2014)

Journal Details
Format
Journal
eISSN
2353-9003
First Published
19 Apr 2013
Publication timeframe
4 times per year
Languages
English

Search

15 Articles
Open Access

Numerical Effectiveness of Different Formulations of the Rigid Finite Element Method

Published Online: 02 Sep 2014
Page range: 475 - 485

Abstract

Abstract

The paper presents an application of different formulations of the rigid finite element method (RFEM) to dynamic analysis of flexible beams. We discuss numerical effectiveness of the classical RFEM and an alternative approach in which continuity of displacements is preserved by means of constraint equations. The analysis is carried out for a benchmark problem of the spin-up motion in planar and spatial cases. Torsion is omitted for numerical simulations and two cases of the new approach are considered. The results obtained by means of these methods are compared with the results obtained using a nonlinear two-node superelement

Keywords

  • flexibility of links
  • rigid finite element method
  • dynamic analysis
  • nonlinear motion
  • numerical effectiveness
Open Access

Nonlinear Vibrations of Orthogonal Mechanism of Shaking Table

Published Online: 02 Sep 2014
Page range: 487 - 501

Abstract

Abstract

The dynamics of orthogonal mechanism in the presence of a shaking table of fixed cargo is studied. The focus is on the vibrational motion of the mechanism in slow-speed motor rotation. The analysis of the solutions for motion nonlinear equations showed that the angular velocity of the guiding link oscillates according to the harmonic law about a mean value. The character of changing its amplitude, depending on the weight of the cargo and the length of the guiding link, is determined. Dependence of the mean angular velocity on the motor torque is set.

Keywords

  • orthogonal mechanism
  • dynamics
  • asymptotic method
  • essentially nonlinearity
  • stability
Open Access

Analysis of Links Positions in Landing Gear Mechanism

Published Online: 02 Sep 2014
Page range: 503 - 512

Abstract

Abstract

This article contains a kinematic analysis of an aircraft chassis mechanism in a range of positions. The mechanism of the chassis is made up of several smaller subsystems with different functions. The first mechanism is used to eject the chassis before landing (touchdown) and fold it to hatchway after the lift off. The second mechanism is designed to perform rotation of the crossover with the wheel, in order to adjust the position of the wheel to fit it in the limited space in the hold. The third mechanism allows movement of the chassis resulting from the change in length of the damper. To determine the position of the following links of the mechanism calculus of vectors was applied in which unit vectors were used to represent the angular position of the links. The aim of the analysis is to determine the angle of convergence and the angle of heel wheels as a function of the variable length of hydraulic cylinder, length of the shock absorber, length of the regulations rods

Keywords

  • aircrafts
  • landing gear
  • mechanics
  • kinematics
Open Access

A Specific Problem of Mechanism Synthesis

Published Online: 02 Sep 2014
Page range: 513 - 522

Abstract

Abstract

A technique for path synthesis is employed to design a feeder for carrying products between two points. The feeder is assumed to be a one degree of freedom system of six links connected by means of revolute joints. The mathematical basis of the concept is presented. An exemplary solution is presented and discussed

Keywords

  • six-bar linkage
  • path synthesis
  • feeder design
Open Access

Parameters Estimation for the Spherical Model of the Human Knee Joint Using Vector Method

Published Online: 02 Sep 2014
Page range: 523 - 537

Abstract

Abstract

Position and displacement analysis of a spherical model of a human knee joint using the vector method was presented. Sensitivity analysis and parameter estimation were performed using the evolutionary algorithm method. Computer simulations for the mechanism with estimated parameters proved the effectiveness of the prepared software. The method itself can be useful when solving problems concerning the displacement and loads analysis in the knee joint

Keywords

  • model
  • knee joint
  • vector method
  • estimation
  • position and displacements
Open Access

Application of Multi-Valued Weighting Logical Functions in the Analysis of a Degree of Importance of Construction Parameters on the Example of Hydraulic Valves

Published Online: 02 Sep 2014
Page range: 539 - 548

Abstract

Abstract

In the optimization process, changes in the construction parameters value influence the behaviour of functions depending on time. Weighting logical coefficients for the stabilisation time are taken into consideration here, i.e., a shorter (better) stabilisation time has a more important (bigger) value of the weighting coefficient. An example of applying weighting logical functions in the analysis of a degree of importance of construction parameters of a hydraulic valve is presented in the paper

Keywords

  • optimization process
  • weighting logical coefficients
  • hydraulic valves
  • pomps
Open Access

Decision Optimization of Machine Sets Taking Into Consideration Logical Tree Minimization of Design Guidelines

Published Online: 02 Sep 2014
Page range: 549 - 561

Abstract

Abstract

The method of minimization of complex partial multi-valued logical functions determines the degree of importance of construction and exploitation parameters playing the role of logical decision variables. Logical functions are taken into consideration in the issues of modelling machine sets. In multi-valued logical functions with weighting products, it is possible to use a modified Quine - McCluskey algorithm of multi-valued functions minimization. Taking into account weighting coefficients in the logical tree minimization reflects a physical model of the object being analysed much better

Keywords

  • optimization
  • logical tree minimization
  • modified Quine- McCluskey algorithm
  • proportional valve
Open Access

Graph Models of Automobile Gears - Kinematics

Published Online: 02 Sep 2014
Page range: 563 - 573

Abstract

Abstract

In the present paper, kinematical analysis of an automotive gear is described. Versatile graph based methods have been utilized for this purpose. An application of mixed, contour and bond graphs gives the same results. It allows the detection of possible mistakes as well as a deeper insight into the designed artifact. The graphs can also be used for further analyses which will be published in a separate document

Keywords

  • kinematical analysis
  • ratios
  • mixed graphs
  • contour graphs
  • bond graphs
Open Access

Neuro-Fuzzy Control of a Robotic Manipulator

Published Online: 02 Sep 2014
Page range: 575 - 584

Abstract

Abstract

In this paper, to solve the problem of control of a robotic manipulator’s movement with holonomical constraints, an intelligent control system was used. This system is understood as a hybrid controller, being a combination of fuzzy logic and an artificial neural network. The purpose of the neuro-fuzzy system is the approximation of the nonlinearity of the robotic manipulator’s dynamic to generate a compensatory control. The control system is designed in such a way as to permit modification of its properties under different operating conditions of the two-link manipulator

Keywords

  • robotic manipulator
  • force control
  • neuro-fuzzy system
Open Access

Dynamic Axle Load of an Automotive Vehicle When Driven on a Mobile Measurement Platform

Published Online: 02 Sep 2014
Page range: 585 - 597

Abstract

Abstract

An analysis of the dynamic axle load of an automotive vehicle (AV) when it is driven on a mobile measurement platform is presented in this paper. During the ride, the time characteristic of the dynamic force N(t), acting on the axle, was recorded. The effect of the vehicle axle mass on the maximum dynamic force value and the dynamic coefficient were studied. On this basis it was attempted to calculate the total vehicle’s weight. Conclusions concerning the dynamic loads of the vehicle axles in relation to the reduced axle mass, were drawn. The optimal axle mass value, for which the dynamic coefficient reaches a minimum, was calculated

Keywords

  • mechanic vibrations
  • dynamic load
  • automotive vehicle axle
Open Access

Motion Planning of a Novel 2-DOF Parallel Manipulator Applied as Driving Simulator of the Wheel Loader

Published Online: 02 Sep 2014
Page range: 599 - 608

Abstract

Abstract

A novel parallel manipulator with 3 legs (2 actuated by linear actuators and one supporting pillar),which is applied in a wheel loader driving simulator, is proposed in this paper. The roll angle and the pitch angle of the platform are derived in closed-form of functions of the variable lengths of two actuators. The linear velocity and acceleration of the selected point and angular velocity of the moving platform are determined and compared with measurement results obtained in the respective point and in the body of the wheel loader. The differences between the desired and actual actuator displacements are used as feedback to compute how much force to send to the actuators as some function of the servo error. A numerical example with a proposed mechanism as a driving simulator is presented

Keywords

  • simulator
  • wheel loader driving
  • motion planning
Open Access

Static and Dynamic Analysis of a Pump Impeller with a Balancing Device Part I: Static Analysis

Published Online: 02 Sep 2014
Page range: 609 - 619

Abstract

Abstract

This part of the work presents the design and static analysis of an impeller for a single-stage pump. The impeller is directly connected with a balancing device. The impeller needs to have a properly designed system of longitudinal and lateral clearances on both sides. With the simplifying assumptions concerning the flow and distribution of pressure in the longitudinal and lateral clearances, the static analysis involved deriving relationships between the impeller geometry and the basic performance parameters of the pump. A numerical example was used to show the calculation procedure of static characteristics for the predetermined parameters

Keywords

  • pump impeller
  • balance device
  • static analysis
Open Access

Static and Dynamics of a Pump Impeller with a Balancing Device Part II: Dynamic Analysis

Published Online: 02 Sep 2014
Page range: 621 - 631

Abstract

Abstract

This paper presents the theoretical study of the system comprising an impeller and a balancing device. It deals with the dynamic analysis of the system, i.e., the axial vibrations of the impeller, and the system stability. The dynamic analysis took into account linearized hydrodynamic forces and moments generated in the longitudinal clearances of the seals of the impeller. The theoretical analysis was supplemented with a numerical example with characteristics determined for a real single-stage centrifugal pump

Keywords

  • dynamic analysis
  • pump impeller
  • balance device
  • stability condition
Open Access

The Analysis of Pedaling Techniques with Platform Pedals

Published Online: 02 Sep 2014
Page range: 633 - 642

Abstract

Abstract

The paper analyzes a pedaling technique with platform pedals in which the influence of the geometric and tribological parameters on the torque course of the active forces in the crank rotation axis is determined. Distribution of forces of feet acting on pedals as a function of the crank rotation angle was performed and on this basis the specific pedaling zones and their ranges and the courses of the value of variable active torque and pedaling work during the full cycle were determined. The course of changes in the movements in the ankle joint is described with a function depending on the crank and limb position and loading of the joint. A numerical example has also been presented and a discussion of the results has been carried out

Keywords

  • cycling
  • platform-pedal
  • pedaling
  • cycling efficiency
Open Access

Differential Kinematics Of Contemporary Industrial Robots

Published Online: 02 Sep 2014
Page range: 643 - 659

Abstract

Abstract

The paper presents a simple method of avoiding singular configurations of contemporary industrial robot manipulators of such renowned companies as ABB, Fanuc, Mitsubishi, Adept, Kawasaki, COMAU and KUKA. To determine the singular configurations of these manipulators a global form of description of the end-effector kinematics was prepared, relative to the other links. On the basis of this description , the formula for the Jacobian was defined in the end-effector coordinates. Next, a closed form of the determinant of the Jacobian was derived. From the formula, singular configurations, where the determinant’s value equals zero, were determined. Additionally, geometric interpretations of these configurations were given and they were illustrated. For the exemplary manipulator, small corrections of joint variables preventing the reduction of the Jacobian order were suggested. An analysis of positional errors, caused by these corrections, was presented

Keywords

  • kinematics
  • manipulators
  • mechanical system
  • robot kinematics
15 Articles
Open Access

Numerical Effectiveness of Different Formulations of the Rigid Finite Element Method

Published Online: 02 Sep 2014
Page range: 475 - 485

Abstract

Abstract

The paper presents an application of different formulations of the rigid finite element method (RFEM) to dynamic analysis of flexible beams. We discuss numerical effectiveness of the classical RFEM and an alternative approach in which continuity of displacements is preserved by means of constraint equations. The analysis is carried out for a benchmark problem of the spin-up motion in planar and spatial cases. Torsion is omitted for numerical simulations and two cases of the new approach are considered. The results obtained by means of these methods are compared with the results obtained using a nonlinear two-node superelement

Keywords

  • flexibility of links
  • rigid finite element method
  • dynamic analysis
  • nonlinear motion
  • numerical effectiveness
Open Access

Nonlinear Vibrations of Orthogonal Mechanism of Shaking Table

Published Online: 02 Sep 2014
Page range: 487 - 501

Abstract

Abstract

The dynamics of orthogonal mechanism in the presence of a shaking table of fixed cargo is studied. The focus is on the vibrational motion of the mechanism in slow-speed motor rotation. The analysis of the solutions for motion nonlinear equations showed that the angular velocity of the guiding link oscillates according to the harmonic law about a mean value. The character of changing its amplitude, depending on the weight of the cargo and the length of the guiding link, is determined. Dependence of the mean angular velocity on the motor torque is set.

Keywords

  • orthogonal mechanism
  • dynamics
  • asymptotic method
  • essentially nonlinearity
  • stability
Open Access

Analysis of Links Positions in Landing Gear Mechanism

Published Online: 02 Sep 2014
Page range: 503 - 512

Abstract

Abstract

This article contains a kinematic analysis of an aircraft chassis mechanism in a range of positions. The mechanism of the chassis is made up of several smaller subsystems with different functions. The first mechanism is used to eject the chassis before landing (touchdown) and fold it to hatchway after the lift off. The second mechanism is designed to perform rotation of the crossover with the wheel, in order to adjust the position of the wheel to fit it in the limited space in the hold. The third mechanism allows movement of the chassis resulting from the change in length of the damper. To determine the position of the following links of the mechanism calculus of vectors was applied in which unit vectors were used to represent the angular position of the links. The aim of the analysis is to determine the angle of convergence and the angle of heel wheels as a function of the variable length of hydraulic cylinder, length of the shock absorber, length of the regulations rods

Keywords

  • aircrafts
  • landing gear
  • mechanics
  • kinematics
Open Access

A Specific Problem of Mechanism Synthesis

Published Online: 02 Sep 2014
Page range: 513 - 522

Abstract

Abstract

A technique for path synthesis is employed to design a feeder for carrying products between two points. The feeder is assumed to be a one degree of freedom system of six links connected by means of revolute joints. The mathematical basis of the concept is presented. An exemplary solution is presented and discussed

Keywords

  • six-bar linkage
  • path synthesis
  • feeder design
Open Access

Parameters Estimation for the Spherical Model of the Human Knee Joint Using Vector Method

Published Online: 02 Sep 2014
Page range: 523 - 537

Abstract

Abstract

Position and displacement analysis of a spherical model of a human knee joint using the vector method was presented. Sensitivity analysis and parameter estimation were performed using the evolutionary algorithm method. Computer simulations for the mechanism with estimated parameters proved the effectiveness of the prepared software. The method itself can be useful when solving problems concerning the displacement and loads analysis in the knee joint

Keywords

  • model
  • knee joint
  • vector method
  • estimation
  • position and displacements
Open Access

Application of Multi-Valued Weighting Logical Functions in the Analysis of a Degree of Importance of Construction Parameters on the Example of Hydraulic Valves

Published Online: 02 Sep 2014
Page range: 539 - 548

Abstract

Abstract

In the optimization process, changes in the construction parameters value influence the behaviour of functions depending on time. Weighting logical coefficients for the stabilisation time are taken into consideration here, i.e., a shorter (better) stabilisation time has a more important (bigger) value of the weighting coefficient. An example of applying weighting logical functions in the analysis of a degree of importance of construction parameters of a hydraulic valve is presented in the paper

Keywords

  • optimization process
  • weighting logical coefficients
  • hydraulic valves
  • pomps
Open Access

Decision Optimization of Machine Sets Taking Into Consideration Logical Tree Minimization of Design Guidelines

Published Online: 02 Sep 2014
Page range: 549 - 561

Abstract

Abstract

The method of minimization of complex partial multi-valued logical functions determines the degree of importance of construction and exploitation parameters playing the role of logical decision variables. Logical functions are taken into consideration in the issues of modelling machine sets. In multi-valued logical functions with weighting products, it is possible to use a modified Quine - McCluskey algorithm of multi-valued functions minimization. Taking into account weighting coefficients in the logical tree minimization reflects a physical model of the object being analysed much better

Keywords

  • optimization
  • logical tree minimization
  • modified Quine- McCluskey algorithm
  • proportional valve
Open Access

Graph Models of Automobile Gears - Kinematics

Published Online: 02 Sep 2014
Page range: 563 - 573

Abstract

Abstract

In the present paper, kinematical analysis of an automotive gear is described. Versatile graph based methods have been utilized for this purpose. An application of mixed, contour and bond graphs gives the same results. It allows the detection of possible mistakes as well as a deeper insight into the designed artifact. The graphs can also be used for further analyses which will be published in a separate document

Keywords

  • kinematical analysis
  • ratios
  • mixed graphs
  • contour graphs
  • bond graphs
Open Access

Neuro-Fuzzy Control of a Robotic Manipulator

Published Online: 02 Sep 2014
Page range: 575 - 584

Abstract

Abstract

In this paper, to solve the problem of control of a robotic manipulator’s movement with holonomical constraints, an intelligent control system was used. This system is understood as a hybrid controller, being a combination of fuzzy logic and an artificial neural network. The purpose of the neuro-fuzzy system is the approximation of the nonlinearity of the robotic manipulator’s dynamic to generate a compensatory control. The control system is designed in such a way as to permit modification of its properties under different operating conditions of the two-link manipulator

Keywords

  • robotic manipulator
  • force control
  • neuro-fuzzy system
Open Access

Dynamic Axle Load of an Automotive Vehicle When Driven on a Mobile Measurement Platform

Published Online: 02 Sep 2014
Page range: 585 - 597

Abstract

Abstract

An analysis of the dynamic axle load of an automotive vehicle (AV) when it is driven on a mobile measurement platform is presented in this paper. During the ride, the time characteristic of the dynamic force N(t), acting on the axle, was recorded. The effect of the vehicle axle mass on the maximum dynamic force value and the dynamic coefficient were studied. On this basis it was attempted to calculate the total vehicle’s weight. Conclusions concerning the dynamic loads of the vehicle axles in relation to the reduced axle mass, were drawn. The optimal axle mass value, for which the dynamic coefficient reaches a minimum, was calculated

Keywords

  • mechanic vibrations
  • dynamic load
  • automotive vehicle axle
Open Access

Motion Planning of a Novel 2-DOF Parallel Manipulator Applied as Driving Simulator of the Wheel Loader

Published Online: 02 Sep 2014
Page range: 599 - 608

Abstract

Abstract

A novel parallel manipulator with 3 legs (2 actuated by linear actuators and one supporting pillar),which is applied in a wheel loader driving simulator, is proposed in this paper. The roll angle and the pitch angle of the platform are derived in closed-form of functions of the variable lengths of two actuators. The linear velocity and acceleration of the selected point and angular velocity of the moving platform are determined and compared with measurement results obtained in the respective point and in the body of the wheel loader. The differences between the desired and actual actuator displacements are used as feedback to compute how much force to send to the actuators as some function of the servo error. A numerical example with a proposed mechanism as a driving simulator is presented

Keywords

  • simulator
  • wheel loader driving
  • motion planning
Open Access

Static and Dynamic Analysis of a Pump Impeller with a Balancing Device Part I: Static Analysis

Published Online: 02 Sep 2014
Page range: 609 - 619

Abstract

Abstract

This part of the work presents the design and static analysis of an impeller for a single-stage pump. The impeller is directly connected with a balancing device. The impeller needs to have a properly designed system of longitudinal and lateral clearances on both sides. With the simplifying assumptions concerning the flow and distribution of pressure in the longitudinal and lateral clearances, the static analysis involved deriving relationships between the impeller geometry and the basic performance parameters of the pump. A numerical example was used to show the calculation procedure of static characteristics for the predetermined parameters

Keywords

  • pump impeller
  • balance device
  • static analysis
Open Access

Static and Dynamics of a Pump Impeller with a Balancing Device Part II: Dynamic Analysis

Published Online: 02 Sep 2014
Page range: 621 - 631

Abstract

Abstract

This paper presents the theoretical study of the system comprising an impeller and a balancing device. It deals with the dynamic analysis of the system, i.e., the axial vibrations of the impeller, and the system stability. The dynamic analysis took into account linearized hydrodynamic forces and moments generated in the longitudinal clearances of the seals of the impeller. The theoretical analysis was supplemented with a numerical example with characteristics determined for a real single-stage centrifugal pump

Keywords

  • dynamic analysis
  • pump impeller
  • balance device
  • stability condition
Open Access

The Analysis of Pedaling Techniques with Platform Pedals

Published Online: 02 Sep 2014
Page range: 633 - 642

Abstract

Abstract

The paper analyzes a pedaling technique with platform pedals in which the influence of the geometric and tribological parameters on the torque course of the active forces in the crank rotation axis is determined. Distribution of forces of feet acting on pedals as a function of the crank rotation angle was performed and on this basis the specific pedaling zones and their ranges and the courses of the value of variable active torque and pedaling work during the full cycle were determined. The course of changes in the movements in the ankle joint is described with a function depending on the crank and limb position and loading of the joint. A numerical example has also been presented and a discussion of the results has been carried out

Keywords

  • cycling
  • platform-pedal
  • pedaling
  • cycling efficiency
Open Access

Differential Kinematics Of Contemporary Industrial Robots

Published Online: 02 Sep 2014
Page range: 643 - 659

Abstract

Abstract

The paper presents a simple method of avoiding singular configurations of contemporary industrial robot manipulators of such renowned companies as ABB, Fanuc, Mitsubishi, Adept, Kawasaki, COMAU and KUKA. To determine the singular configurations of these manipulators a global form of description of the end-effector kinematics was prepared, relative to the other links. On the basis of this description , the formula for the Jacobian was defined in the end-effector coordinates. Next, a closed form of the determinant of the Jacobian was derived. From the formula, singular configurations, where the determinant’s value equals zero, were determined. Additionally, geometric interpretations of these configurations were given and they were illustrated. For the exemplary manipulator, small corrections of joint variables preventing the reduction of the Jacobian order were suggested. An analysis of positional errors, caused by these corrections, was presented

Keywords

  • kinematics
  • manipulators
  • mechanical system
  • robot kinematics

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