Mircea Neagoe | Transylvania University of Brasov (original) (raw)

Papers by Mircea Neagoe

Research paper thumbnail of On the Kinematic Calibration of a Stewart Platform

This paper presents several results regarding the kinematic calibration of a Stewart platform. Fi... more This paper presents several results regarding the kinematic calibration of a Stewart platform. Firstly, a general method for the precision modeling of parallel robots is proposed by the authors and applied in the case of the Stewart platform. Thus, an accuracy model of the Stewart platform is established, taking into account the errors of the geometrical parameters. Next, on the basis of the precision model and the experimental data for the accuracy of the Stewart platform, some algorithms used in kinematic calibration were generated and tested; overcoming some numerical difficulties, the actual deviations of the geometrical parameters were identified. Thus, the correct values of geometrical parameters and, implicitly, the correct kinematic model used in command/control were obtained. Finally, the importance of the calibration in the optimization of the kinematic models is emphasized, based on the numerical results. According to these aspects, the accuracy of the Stewart platform model was significantly increased.

Research paper thumbnail of Correction to: Emerging Issues and Challenges with the Integration of Solar Power Plants into Power Systems

Springer proceedings in energy, 2020

The original version of this chapter's first reference had wrong URLs as CrossRef and Google Scho... more The original version of this chapter's first reference had wrong URLs as CrossRef and Google Scholar & reference 108 had incorrect title of the paper and wrong Google Scholar, CrossRef. These have been corrected. The correction chapter has been updated with the changes.

Research paper thumbnail of Emerging Issues and Challenges with the Integration of Solar Power Plants into Power Systems

Springer proceedings in energy, 2020

The characteristics of solar-generated electricity, including intermittency, uncertainty, and non... more The characteristics of solar-generated electricity, including intermittency, uncertainty, and non-synchronous power generation, lead to some technical challenges to large-scale power grid integration. Each of those characteristics causes an economic challenge as well as reverse power flow, power quality issues, dynamic stability, and big data challenges. This paper aims to comprehensively investigate the existing challenges with the integration of high-penetration solar power plants, particularly Photovoltaic (PV) power plants, into power systems and corresponding solutions to improve the security, reliability, and resiliency of power systems.

Research paper thumbnail of On the Use of the Vaucanson Planetary Transmission in the Renewable Energy Systems. Part II: Power Circulation and Efficiency

The paper main objective is to model and analyze the properties of the Vaucanson planetary transm... more The paper main objective is to model and analyze the properties of the Vaucanson planetary transmission for using it as reducer or amplifier in the renewable energy systems. The power circulation and the efficiency of the initial Vaucanson reducer are presented in the second part of the paper. On the basis of the presented properties, useful conclusions for the use of the transmission in renewable energy systems are formulated.

Research paper thumbnail of Kinematical and Dynamic Aspects of a Cycloidal Planetary Reducer with Modified Structure

The paper deals with some representative geometrical and dynamic aspects of a new cycloidal reduc... more The paper deals with some representative geometrical and dynamic aspects of a new cycloidal reducer variant with modified structure, proposed by the authors: geometrical optimization of the cycloidal gear, analysis of the transmission ratio and efficiency, and analysis of the dynamic response in a relevant functioning case.

Research paper thumbnail of On the Use of the Vaucanson Planetary Transmission in the Renewable Energy Systems. Part I: Velocities and Torques

The paper main objective is to model and analyze the properties of the Vaucanson planetary transm... more The paper main objective is to model and analyze the properties of the Vaucanson planetary transmission in order to establish the possibility of using it in renewable energy systems. The structural features, the kinematical and static modeling of the initial Vaucanson speed reducer are presented in the first part of the paper.

Research paper thumbnail of Comparative energy performance analysis of four wind turbines with counter-rotating rotors in steady-state regime

Energy Reports, Nov 1, 2022

Research paper thumbnail of Cam Profiles Generation as Follower Envelopes with MATLAB Programs

The paper describes the use of MATLAB software in the synthesis of cam mechanisms as follower env... more The paper describes the use of MATLAB software in the synthesis of cam mechanisms as follower envelopes, using motion data read from file. Disk cams with translating and oscillating followers, flat-faced, pointed and with roller are discussed, as well as wedge cams with roller-follower. Full MATLAB programs are provided, together with the description of the required input Excel files. These can serve to intuitively demonstrate the relationship between follower motion program, follower bias and the occurrence of cam undercut. By importing the MATLAB envelope plots into AutoCAD, the respective cam profiles can be manually extracted to polylines with added accuracy.

Research paper thumbnail of Dynamic features of a planetary speed increaser usable in small hydropower plants

dimension, 2010

Abstract:-The planetary chain transmission analyzed in this paper as a speed increaser for small ... more Abstract:-The planetary chain transmission analyzed in this paper as a speed increaser for small hydropower plants is proposed by the authors. The dynamic model of the chain speed increaser is presented in the paper, based on Lagrange and Newton-Euler methods. The ...

Research paper thumbnail of One-DOF Mechanisms for Dual-Axis Solar Tracking

Springer eBooks, Oct 19, 2013

This paper presents a comparative study of one DOF mechanisms with one input and two correlated o... more This paper presents a comparative study of one DOF mechanisms with one input and two correlated outputs connected to both diurnal and elevation orientation movements from dual-axis solar tracking systems. Based on known solutions from the literature, the paper provides a systematization of the existing one DOF mechanism variants; thus, there were identified two main categories: (a) four-bar spatial linkage, with or without adjusting link lengths, and (b) planar linkage serially connected with a cam mechanism. The comparative kinematical studies of two representative one DOF mechanism variants allow highlighting the advantages and drawbacks each category, the compound mechanism with cylindrical cam and 4R planar linkage being the most recommended for tracking small PV systems. Considering applications based on location Brasov, Romania, there are drawn useful conclusions for researchers, designers and specialists to set the best orientation solution suitable to a given location.

Research paper thumbnail of Solar Heating & Cooling Energy Mixes to Transform Low Energy Buildings in Nearly Zero Energy Buildings

Research paper thumbnail of Sustainable Communities

Green energy and technology, 2020

Research paper thumbnail of Modeling and Optimization of the Global Solar Irradiance Collecting Efficiency

International Journal of Green Energy, Nov 21, 2014

ABSTRACT This article presents a mathematical model for estimating the direction of the maximal g... more ABSTRACT This article presents a mathematical model for estimating the direction of the maximal global solar irradiance (MGSI) based on actual values of direct/beam and diffuse irradiance, model that can be used to determine a correct value of the global collecting efficiency of solar tracking systems. Using this model, the collecting efficiency can be improved by tracking the solar conversion surface to minimize its incidence angle with the maximal global irradiance instead of the beam irradiance. The analysis of the numerical results obtained using in-field data-based simulations showed a significant improvement of the real collecting efficiency, especially during cloudy days when the diffuse irradiance is preponderant.

Research paper thumbnail of General method and algorithms used for accuracy modelling of parallel robots

International journal of biomechatronics and biomedical robotics, 2009

The paper deals with a new method and three derived general algorithms useful for accuracy studie... more The paper deals with a new method and three derived general algorithms useful for accuracy studies of parallel robots. The proposed modelling can be used to evaluate the accuracy of parallel-type structure, considering both the independent kinematic parameters and the geometric parameters as error sources. This method is based on the use of homogenous operators and it can be applied to any parallel robot with any configuration and complexity. The results obtained through the accuracy models allow us to establish the region of maximum precision; consequently, the optimal placement of the task becomes possible. Also, the precision models are useful mathematical tools for robot calibration.

Research paper thumbnail of High Degree Accuracy Modelling and Calibration of Serial Robots with Large Errors

Kluwer Academic Publishers eBooks, May 31, 2006

The paper deals with the improvement of accuracy modelling and calibration process, in the case o... more The paper deals with the improvement of accuracy modelling and calibration process, in the case of serial robots with large errors. Beginning from the first degree kinematic modelling, a general third-degree modelling of errors in serial robot chains is generated and applied ...

Research paper thumbnail of On a new cycloidal planetary gear used to fit mechatronic systems of RES

The paper deals with a new variant of a cycloidal planetary transmission (CPT) with modified stru... more The paper deals with a new variant of a cycloidal planetary transmission (CPT) with modified structure, proposed by the authors, able to accomplish high kinematical ratio and high efficiency, useful to fit mechatronic systems of Renewable Energy Systems (RES). Through the conceptual design approach, six new transmission variants were generated and the principle solution was established. Further on, optimization studies on the geometrical features and dynamic behavior of the new planetary gear were performed. Based on a physical prototype and using a modern high-tech stand, experimental researches on the efficiency of the new cycloidal transmission tested as reducer were performed. The obtained experimental results comply with the theoretical model, and some performance features of the transmission prototype are thus derived.

Research paper thumbnail of Dynamic model of a small hydropower plant

The selection of the best turbine for a particular hydro site depends on the site characteristics... more The selection of the best turbine for a particular hydro site depends on the site characteristics and on the power required. For the particular values of the flow and head, the turbine tends to run most efficient at a particular speed. Often, the generator needs to be rotated at a speed greater than the turbine optimum speed. Therefore, a speed

Research paper thumbnail of Comparative analysis of torque-adding wind energy conversion systems with a counter-rotating vs. conventional electric generator

Frontiers in Energy Research

The paper presents a comparative analysis on the steady-state behavior of two counter-rotating wi... more The paper presents a comparative analysis on the steady-state behavior of two counter-rotating wind turbines with same components, where the generator can operate as a counter-rotating (with both a mobile rotor and stator—Case a) vs. conventional (with a fixed stator—Case b) electric machine. These wind energy conversion systems (WECSs) also have two coaxial counter-rotating wind rotors and a one-degree-of-freedom (1-DOF) planetary speed increaser with two inputs and one or two outputs for compatibility with the considered generator. The paper aims at highlighting the efficiency and energy performances of WECSs with a counter-rotating vs. conventional generator by investigating three functional scenarios (A, B, and C) of the two WECS cases (a and b) under the assumption of identical or different counter-rotating wind rotors. A generalized kinetostatic modeling algorithm is first proposed, starting from the general case of WECS with a counter-rotating generator, which allows the esta...

Research paper thumbnail of Dynamic Analysis of a Delta Parallel Robot with Flexible Links and Joint Clearances

Applied Sciences

Delta robot is a lightweight parallel manipulator capable of accurately moving heavy loads at hig... more Delta robot is a lightweight parallel manipulator capable of accurately moving heavy loads at high speed and acceleration along a spatial trajectory. This intensive dynamic process may have a significant impact on the end-effector trajectory precision and motor behavior. The paper highlights the influence on the dynamic behavior of a Delta robot by considering individual and combined effects of clearances and friction in the spherical joints, as well as the flexibility of the rod elements. The CAD modeling of the Delta robot and its motion simulation on a representative spatial trajectory where the maximum allowed values of speed and acceleration are reached were performed using the Catia and Adams software packages. The obtained results show that the methods used were successfully applied and the effects are mutually interconnected, but not cumulative.

Research paper thumbnail of Steady-State Modeling and Simulation of a 1-DOF Dual-Input and Dual-Output Planetary Speed Increaser for Counter-Rotating Wind Turbines

Mechanisms and machine science, 2022

Research paper thumbnail of On the Kinematic Calibration of a Stewart Platform

This paper presents several results regarding the kinematic calibration of a Stewart platform. Fi... more This paper presents several results regarding the kinematic calibration of a Stewart platform. Firstly, a general method for the precision modeling of parallel robots is proposed by the authors and applied in the case of the Stewart platform. Thus, an accuracy model of the Stewart platform is established, taking into account the errors of the geometrical parameters. Next, on the basis of the precision model and the experimental data for the accuracy of the Stewart platform, some algorithms used in kinematic calibration were generated and tested; overcoming some numerical difficulties, the actual deviations of the geometrical parameters were identified. Thus, the correct values of geometrical parameters and, implicitly, the correct kinematic model used in command/control were obtained. Finally, the importance of the calibration in the optimization of the kinematic models is emphasized, based on the numerical results. According to these aspects, the accuracy of the Stewart platform model was significantly increased.

Research paper thumbnail of Correction to: Emerging Issues and Challenges with the Integration of Solar Power Plants into Power Systems

Springer proceedings in energy, 2020

The original version of this chapter's first reference had wrong URLs as CrossRef and Google Scho... more The original version of this chapter's first reference had wrong URLs as CrossRef and Google Scholar & reference 108 had incorrect title of the paper and wrong Google Scholar, CrossRef. These have been corrected. The correction chapter has been updated with the changes.

Research paper thumbnail of Emerging Issues and Challenges with the Integration of Solar Power Plants into Power Systems

Springer proceedings in energy, 2020

The characteristics of solar-generated electricity, including intermittency, uncertainty, and non... more The characteristics of solar-generated electricity, including intermittency, uncertainty, and non-synchronous power generation, lead to some technical challenges to large-scale power grid integration. Each of those characteristics causes an economic challenge as well as reverse power flow, power quality issues, dynamic stability, and big data challenges. This paper aims to comprehensively investigate the existing challenges with the integration of high-penetration solar power plants, particularly Photovoltaic (PV) power plants, into power systems and corresponding solutions to improve the security, reliability, and resiliency of power systems.

Research paper thumbnail of On the Use of the Vaucanson Planetary Transmission in the Renewable Energy Systems. Part II: Power Circulation and Efficiency

The paper main objective is to model and analyze the properties of the Vaucanson planetary transm... more The paper main objective is to model and analyze the properties of the Vaucanson planetary transmission for using it as reducer or amplifier in the renewable energy systems. The power circulation and the efficiency of the initial Vaucanson reducer are presented in the second part of the paper. On the basis of the presented properties, useful conclusions for the use of the transmission in renewable energy systems are formulated.

Research paper thumbnail of Kinematical and Dynamic Aspects of a Cycloidal Planetary Reducer with Modified Structure

The paper deals with some representative geometrical and dynamic aspects of a new cycloidal reduc... more The paper deals with some representative geometrical and dynamic aspects of a new cycloidal reducer variant with modified structure, proposed by the authors: geometrical optimization of the cycloidal gear, analysis of the transmission ratio and efficiency, and analysis of the dynamic response in a relevant functioning case.

Research paper thumbnail of On the Use of the Vaucanson Planetary Transmission in the Renewable Energy Systems. Part I: Velocities and Torques

The paper main objective is to model and analyze the properties of the Vaucanson planetary transm... more The paper main objective is to model and analyze the properties of the Vaucanson planetary transmission in order to establish the possibility of using it in renewable energy systems. The structural features, the kinematical and static modeling of the initial Vaucanson speed reducer are presented in the first part of the paper.

Research paper thumbnail of Comparative energy performance analysis of four wind turbines with counter-rotating rotors in steady-state regime

Energy Reports, Nov 1, 2022

Research paper thumbnail of Cam Profiles Generation as Follower Envelopes with MATLAB Programs

The paper describes the use of MATLAB software in the synthesis of cam mechanisms as follower env... more The paper describes the use of MATLAB software in the synthesis of cam mechanisms as follower envelopes, using motion data read from file. Disk cams with translating and oscillating followers, flat-faced, pointed and with roller are discussed, as well as wedge cams with roller-follower. Full MATLAB programs are provided, together with the description of the required input Excel files. These can serve to intuitively demonstrate the relationship between follower motion program, follower bias and the occurrence of cam undercut. By importing the MATLAB envelope plots into AutoCAD, the respective cam profiles can be manually extracted to polylines with added accuracy.

Research paper thumbnail of Dynamic features of a planetary speed increaser usable in small hydropower plants

dimension, 2010

Abstract:-The planetary chain transmission analyzed in this paper as a speed increaser for small ... more Abstract:-The planetary chain transmission analyzed in this paper as a speed increaser for small hydropower plants is proposed by the authors. The dynamic model of the chain speed increaser is presented in the paper, based on Lagrange and Newton-Euler methods. The ...

Research paper thumbnail of One-DOF Mechanisms for Dual-Axis Solar Tracking

Springer eBooks, Oct 19, 2013

This paper presents a comparative study of one DOF mechanisms with one input and two correlated o... more This paper presents a comparative study of one DOF mechanisms with one input and two correlated outputs connected to both diurnal and elevation orientation movements from dual-axis solar tracking systems. Based on known solutions from the literature, the paper provides a systematization of the existing one DOF mechanism variants; thus, there were identified two main categories: (a) four-bar spatial linkage, with or without adjusting link lengths, and (b) planar linkage serially connected with a cam mechanism. The comparative kinematical studies of two representative one DOF mechanism variants allow highlighting the advantages and drawbacks each category, the compound mechanism with cylindrical cam and 4R planar linkage being the most recommended for tracking small PV systems. Considering applications based on location Brasov, Romania, there are drawn useful conclusions for researchers, designers and specialists to set the best orientation solution suitable to a given location.

Research paper thumbnail of Solar Heating & Cooling Energy Mixes to Transform Low Energy Buildings in Nearly Zero Energy Buildings

Research paper thumbnail of Sustainable Communities

Green energy and technology, 2020

Research paper thumbnail of Modeling and Optimization of the Global Solar Irradiance Collecting Efficiency

International Journal of Green Energy, Nov 21, 2014

ABSTRACT This article presents a mathematical model for estimating the direction of the maximal g... more ABSTRACT This article presents a mathematical model for estimating the direction of the maximal global solar irradiance (MGSI) based on actual values of direct/beam and diffuse irradiance, model that can be used to determine a correct value of the global collecting efficiency of solar tracking systems. Using this model, the collecting efficiency can be improved by tracking the solar conversion surface to minimize its incidence angle with the maximal global irradiance instead of the beam irradiance. The analysis of the numerical results obtained using in-field data-based simulations showed a significant improvement of the real collecting efficiency, especially during cloudy days when the diffuse irradiance is preponderant.

Research paper thumbnail of General method and algorithms used for accuracy modelling of parallel robots

International journal of biomechatronics and biomedical robotics, 2009

The paper deals with a new method and three derived general algorithms useful for accuracy studie... more The paper deals with a new method and three derived general algorithms useful for accuracy studies of parallel robots. The proposed modelling can be used to evaluate the accuracy of parallel-type structure, considering both the independent kinematic parameters and the geometric parameters as error sources. This method is based on the use of homogenous operators and it can be applied to any parallel robot with any configuration and complexity. The results obtained through the accuracy models allow us to establish the region of maximum precision; consequently, the optimal placement of the task becomes possible. Also, the precision models are useful mathematical tools for robot calibration.

Research paper thumbnail of High Degree Accuracy Modelling and Calibration of Serial Robots with Large Errors

Kluwer Academic Publishers eBooks, May 31, 2006

The paper deals with the improvement of accuracy modelling and calibration process, in the case o... more The paper deals with the improvement of accuracy modelling and calibration process, in the case of serial robots with large errors. Beginning from the first degree kinematic modelling, a general third-degree modelling of errors in serial robot chains is generated and applied ...

Research paper thumbnail of On a new cycloidal planetary gear used to fit mechatronic systems of RES

The paper deals with a new variant of a cycloidal planetary transmission (CPT) with modified stru... more The paper deals with a new variant of a cycloidal planetary transmission (CPT) with modified structure, proposed by the authors, able to accomplish high kinematical ratio and high efficiency, useful to fit mechatronic systems of Renewable Energy Systems (RES). Through the conceptual design approach, six new transmission variants were generated and the principle solution was established. Further on, optimization studies on the geometrical features and dynamic behavior of the new planetary gear were performed. Based on a physical prototype and using a modern high-tech stand, experimental researches on the efficiency of the new cycloidal transmission tested as reducer were performed. The obtained experimental results comply with the theoretical model, and some performance features of the transmission prototype are thus derived.

Research paper thumbnail of Dynamic model of a small hydropower plant

The selection of the best turbine for a particular hydro site depends on the site characteristics... more The selection of the best turbine for a particular hydro site depends on the site characteristics and on the power required. For the particular values of the flow and head, the turbine tends to run most efficient at a particular speed. Often, the generator needs to be rotated at a speed greater than the turbine optimum speed. Therefore, a speed

Research paper thumbnail of Comparative analysis of torque-adding wind energy conversion systems with a counter-rotating vs. conventional electric generator

Frontiers in Energy Research

The paper presents a comparative analysis on the steady-state behavior of two counter-rotating wi... more The paper presents a comparative analysis on the steady-state behavior of two counter-rotating wind turbines with same components, where the generator can operate as a counter-rotating (with both a mobile rotor and stator—Case a) vs. conventional (with a fixed stator—Case b) electric machine. These wind energy conversion systems (WECSs) also have two coaxial counter-rotating wind rotors and a one-degree-of-freedom (1-DOF) planetary speed increaser with two inputs and one or two outputs for compatibility with the considered generator. The paper aims at highlighting the efficiency and energy performances of WECSs with a counter-rotating vs. conventional generator by investigating three functional scenarios (A, B, and C) of the two WECS cases (a and b) under the assumption of identical or different counter-rotating wind rotors. A generalized kinetostatic modeling algorithm is first proposed, starting from the general case of WECS with a counter-rotating generator, which allows the esta...

Research paper thumbnail of Dynamic Analysis of a Delta Parallel Robot with Flexible Links and Joint Clearances

Applied Sciences

Delta robot is a lightweight parallel manipulator capable of accurately moving heavy loads at hig... more Delta robot is a lightweight parallel manipulator capable of accurately moving heavy loads at high speed and acceleration along a spatial trajectory. This intensive dynamic process may have a significant impact on the end-effector trajectory precision and motor behavior. The paper highlights the influence on the dynamic behavior of a Delta robot by considering individual and combined effects of clearances and friction in the spherical joints, as well as the flexibility of the rod elements. The CAD modeling of the Delta robot and its motion simulation on a representative spatial trajectory where the maximum allowed values of speed and acceleration are reached were performed using the Catia and Adams software packages. The obtained results show that the methods used were successfully applied and the effects are mutually interconnected, but not cumulative.

Research paper thumbnail of Steady-State Modeling and Simulation of a 1-DOF Dual-Input and Dual-Output Planetary Speed Increaser for Counter-Rotating Wind Turbines

Mechanisms and machine science, 2022