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This dissertation comprises three autonomous essays on topics in labor economics. The first chapter investigates the impact of socio-cultural, technological, and other transformative factors on employees' labor market decisions over recent decades, focusing specifically on the mobility of young workers in terms of job and occupation transitions. Data from the National Longitudinal Surveys of Youth (NLSY79 and NLSY97) indicate a marked increase in job mobility among young participants across different cohorts. Analysis of these datasets demonstrates that the influence of age on the likelihood of changing jobs has become more negative for the second cohort. This shift is primarily driven by changes in the impact of age for specific socio-demographic groups of respondents. Additionally, there is a notable between-cohort rise in the relationship between both upward and downward job transitions and occupational mobility. The second essay explores the consequences of the rise in industrial robot installations on shifts in population size and employment within local labor markets, which may be substantially affected by the rapid advancement of robotics technology in recent decades. The cross-sectional study reveals discernible gender disparities in the impacts of robot adoption. The effect of robotization on the labor force participation rate is negative for men and unmarried women yet positive for married women. As industrial robots are predominantly programmed to perform routine tasks in manufacturing industries traditionally associated with heavy manual male-dominated labor, the anticipated impact of robot exposure on employment in the manufacturing sector is predictably negative for male workers. For women, this effect is conversely positive. It was also found that robot penetration leads to an increase in the share of family income attributed to females within married-couple households. The extended cross-sectional analysis in the third chapter indicates that the impact of robotization on local labor markets is more negative for younger people. Fixed-effects models using panel data analysis reveal that robot adoption unexpectedly reduces migration but enhances labor force participation, opposing recent scholarly findings. Employing an alternative robot adoption variable that is based on technology adoption within individual industries and, therefore, can only be utilized to analyze employment-related dependent variables yields more robust and statistically significant results, indicating a negative impact of robot exposure on employment. Nevertheless, panel data analysis does not support the previous chapter's findings regarding gender differences in the impact of robot penetration. These discrepancies may be attributed to differences in the structure, methodology, and nature of cross-sectional versus panel data and the methodological differences in measuring robotization. / Doctor of Philosophy / This work consists of three separate essays on labor economics. The first chapter looks at how cultural, technological, and other big changes have affected people's job choices over the past few decades. Data from two surveys of young people show that young workers are changing jobs more often now. Age is found to have a bigger negative effect on job changes for the younger cohort. This change mainly affects specific socio-demographic groups. There is also a stronger link between moving up or down in jobs and changing occupations. The second essay examines how the increase in the use of industrial robots affects the population and employment in local labor markets. The study finds that robots affect men and unmarried women negatively but have a positive impact on married women. Since robots usually do routine tasks in manufacturing, which is a male-dominated field, this hurts male workers' job prospects but helps women. Robots also lead to a higher share of family income coming from women in married households. The third chapter shows that robots impact younger people in local job markets more negatively. Using different data, it is found that robots surprisingly reduce migration but increase labor force participation. This finding is different from those of other studies. A new way of measuring robot use within specific industries shows that robots negatively affect employment. However, this new analysis does not support the earlier findings about gender differences. These differences may come from how data is collected and analyzed and the methods used to measure robot use.

Industrirobotar är idag en väsentlig del i tillverkningsindustrin där de bland annat används för att minska kostnader, öka produktivitet och kvalitet och ersätta människor i farliga eller slitsamma uppgifter. Höga krav på noggrannhet och snabbhet hos robotens rörelser innebär också höga krav på de matematiska modeller som ligger till grund för robotens styrsystem. Modellerna används där för att beskriva det komplicerade sambandet mellan robotarmens rörelser och de motorer som orsakar rörelsen. Tillförlitliga modeller är också nödvändiga för exempelvis mekanisk design, simulering av prestanda, diagnos och övervakning. En trend idag är att bygga lättviktsrobotar, vilket innebär att robotens vikt minskas men att den fortfarande kan hantera en lika tung last. Orsaken till detta är främst att minska kostnaden, men också säkerhetsaspekter spelar in. En lättare robotarm ger dock en vekare struktur där elastiska effekter inte längre kan försummas i modellen om man kräver hög prestanda. De elastiska effekterna beskrivs i den matematiska modellen med hjälp av fjädrar och dämpare. Denna avhandling handlar om hur dessa matematiska modeller kan tas fram genom systemidentifiering, vilket är ett viktigt verktyg där mätningar från robotens rörelser används för att bestämma okända parametrar i modellen. Det som mäts är position och moment hos robotens alla motorer. Identifiering av industrirobotar är ett utmanande problem bland annat eftersom robotens beteende varierar beroende på armens position. Den metod som föreslås i avhandlingen innebär att man först identifierar lokala modeller i ett antal positioner. Var och en av dessa beskriver robotens beteende kring en viss arbetspunkt. Sedan anpassas parametrarna i en global modell, som är giltig för alla positioner, så att den så väl som möjligt beskriver det lokala beteendet i de olika positionerna. I avhandlingen analyseras olika metoder för att ta fram lokala modeller. För att få bra resultat krävs att experimenten är omsorgsfullt utformade. För att minska osäkerheten i den globala modellens identifierade parametrar ingår också valet av optimala positioner för experimenten. Olika metoder för att identifiera parametrarna jämförs i avhandlingen och experimentella resultat visar användbarheten av den föreslagna metoden. Den identifierade robotmodellen ger en bra global beskrivning av robotens beteende. Resultatet av forskningen har även gjorts tillgängligt i ett datorverktyg för att noggrant kunna ta fram lokala modeller och identifiera parametrar i dynamiska robotmodeller. / Industrial robots are today essential components in the manufacturing industry where they are used to save costs, increase productivity and quality, and eliminate dangerous and laborious work. High demands on accuracy and speed of the robot motion require that the mathematical models, used in the motion control system, are accurate. The models are used to describe the complicated nonlinear relation between the robot motion and the motors that cause the motion. Accurate dynamic robot models are needed in many areas, such as mechanical design, performance simulation, control, diagnosis, and supervision. A trend in industrial robots is toward lightweight robot structures, where the weight is reduced but with a preserved payload capacity. This is motivated by cost reduction as well as safety issues, but results in a weaker (more compliant) mechanical structure with enhanced elastic effects. For high performance, it is therefore necessary to have models describing these elastic effects. This thesis deals with identification of dynamic robot models, which means that measurements from the robot motion are used to estimate unknown parameters in the models. The measured signals are angular position and torque of the motors. Identifying robot models is a challenging task since an industrial robot is a multivariable, nonlinear, unstable, and resonant system. In this thesis, the unknown parameters (typically spring-damper pairs) in a physically parameterized nonlinear dynamic model are identified, mainly in the frequency domain, using estimates of the nonparametric frequency response function (FRF) in different robot configurations/positions. Each nonparametric FRF then describe the local behavior around an operating point. The nonlinear parametric robot model is linearized in the same operating points and the optimal parameters are obtained by minimizing the discrepancy between the nonparametric FRFs and the parametric FRFs (the FRFs of the linearized parametric robot model). Methods for estimating the nonparametric FRF from experimental data are analyzed with respect to bias, variance, and nonlinearities. In order to accurately estimate the nonparametric FRF, the experiments must be carefully designed. To minimize the uncertainty in the estimated parameters, the selection of optimal robot configurations/positions for the experiments is also part of the design. Different parameter estimators are compared in the thesis and experimental results show the usefulness of the proposed identification procedure. The identified nonlinear robot model gives a good global description of the dynamics in the frequency range of interest. The research work is also implemented and made easily available in a software tool for accurate estimation of nonparametric FRFs as well as parametric robot models.

While the accessibility and technology behind industrial robots is improving as well as becomingless expensive, the installation and conguration of industrial robot cells still proves tobe an expensive venture, especially for small and mid-sized companies. It is therefore of greatinterest to simulate robot cell installations, both for verication of system functionality as wellas for demonstration purposes for clients.However, the construction and conguration of a simulated robot cell is a time-consumingprocess and requires expertise that is often only found in engineers who are experienced withsoftware programming and spacial kinematics. If the process were to be simplied it would bringgreat advantages not only concerning the more ecient use of the time of software engineers butalso in marketing applications.As this paper will show, the use of Virtual Reality (VR) in simulating, displaying andcontrolling robots is a well investigated subject. It has been shown that VR can be used to showrobot simulation in more detail and to specify path movement in task programming. This paperfocuses upon nding and evaluating an intuitive Human Robot Interface (HRI) for interactingwith simulated robots using virtual reality.An HRI is proposed and evaluated, using the Oculus Rift Head Mounted Display (HMD)to display a 3-dimensional (3D) VR environment of a Robot Cell in ABB RobotStudio. Usingmarker-based tracking enabled by ARToolkit, the user's position in real world coordinates isforwarded to the virtual world, along with the position and orientation of a hand-held tool thatallows the user to manipulate the robot targets that are part of the simulated robots program.The system as an HRI was successful in giving the user a strong sense of immersion andgiving them a much better understanding of the robot cell and the positions of the dened robottargets. All participants were also able to dene robot targets much faster with the proposedinterface than when using the standard RobotStudio tools. Results show that the performance ofthe tracking system is adequate with regards to latency and accuracy for updating user positionand hand-held tool when using a video capture resolution of 640x480.

Motion planning is central to the efficient operation and autonomy of robots in the industry. Generally, motion planning of industrial robots is treated in a two-step approach. First, a geometric path between the start and goal position is planned where the objective is to achieve as short path as possible together with avoiding obstacles. Alternatively, a pre-defined geometric path is provided by the end user. Second, the velocity profile along the geometric path is calculated accounting for system dynamics together with other constraints. This approach is computationally efficient, but yield sub-optimal solutions as the system dynamics is not considered in the first step when the geometric path is planned. In this thesis, an alternative to the two-step approach is investigated and a trajectory planner is designed and implemented which plans both the geometric path and the velocity profile simultaneously. The motion planning problem is formulated as an optimal control problem, which is solved by a direct collocation method where the trajectory is parametrised by splines, and the spline nodes and knots are used as optimization variables. The implemented trajectory planner is evaluated in simulations, where the planner is applied to a simple planar elbow robot and ABB's SCARA robot IRB 910SC. Trade-off between computation time and optimality is identified and the results indicate that the trajectory planner yields satisfactory solutions. On the other hand, the simulations indicate that it is not possible to apply the proposed method on a real robot in real-time applications without significant modifications in the implementation to decrease the computation time.

Orientador: João Mauricio Rosario / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-22T16:01:59Z (GMT). No. of bitstreams: 1 Hervella_Cassio_M.pdf: 6637417 bytes, checksum: a9b3d4d37dcc1eba14ccf5bd3013af19 (MD5) Previous issue date: 1997 / Resumo: Neste trabalho foi projetado, desenvolvido e implementado um sistema de controle programável flexível, para aplicação principal no controle de manipuladores e robôs industriais. Como método de abordagem global de um problema de controle automático, podemos dividí-lo em quatro partes principais, a primeira sendo a medição, aquisição e tratamento das grandezas a controlar, a segunda sendo o algoritmo de controle e o sistema de acionamento, a terceira sendo a automatização via programação e simulação de trajetórias e tarefas, e finalmente, a quarta parte sendo a interface homem-máquina. Sendo assim, subdividiu-se o sistema de controle desenvolvido em quatro módulos principais, sendo eles, o módulo de Monitoramento e Supervisão, o módulo de Controle e Acionamento, o módulo de Programação e Simulação e o módulo de Interface com o Usuário; por sua vez, estes módulos são compostos por vários sub-sistemas modulares, que foram projetados, desenvolvidos e testados separadamente, para que fossem flexíveis e confiáveis, tendo sido integrados em seguida, de várias maneiras, de modo a atender às características específicas de cada aplicação. Dentre os sistemas desenvolvidos, temos, por exemplo, interfaces de interface de entrada e saída de dados digitais, interfaces de supervisão de posição, interfaces de acionamento de potência, interfaces de decodificação de sinais de encoders; programas de testes para as interfaces desenvolvidas, programa de interface gráfica para utilização pelo usuário, e outros. Numa aplicação típica, no controle de um robô industrial, podemos ter diversos tipos de atuadores, sensores, mecanismos e arquiteturas do sistema mecânico a controlar, assim, com a substituição de alguns módulos, obtêm-se uma integração flexível que atende as necessidades de cada caso, sem que seja necessário um sistema de controle completamente novo, tomando a automação mais simples, eficiente e rápida. Por exemplo, na automação de um robô, podem ser necessários dois computadores, para que as cargas de processamento de dados de controle e a carga de processamento da interface gráfica com o usuário possam ser divididas entre estes; porém, numa aplicação, como o posicionamento de uma câmera de vídeo, a simplicidade do sistema mecânico, permite a utilização de um único computador, ou mesmo, uma interface dedicada, sendo mantida toda a estrutura global do sistema de controle / Abstract: In this work, it has been designed, developed and implemented a programmable flexible control system, for main application in the control of manipulators and industrial robots. As a global approaxing method for an automatic control problem, we can divide it in four main parts, the first beeing the measument, aquisition and treatment of the variables to control, the second beeing the control algorithm and the actioning system, the third beeing the automation throw programming and simulating of jobs and trajectories, and finally,the fourth beeing the man-machineinterface. Thus, we divided the developed control system in four main modules, which are, the Monitoring and Supervising module, the Actioning and Control module, the Simutation and Programming module and the User's Interface; which are compound by various modular subsystems, that were designed, developed and tested separately, so that they would be dependable and flexible, beeing then integrated, in many ways, to full-fill the specific caracteristics of each application. Within the developed systems, we have, for example, digital data input and output interface boards, position supervising boards, power driving boards, encoder sinal decodifying boards; test programs for the developed boards, graphics interface program to be utilized by the user, and others. In a tipical application, in controlling an industrial robot, we can have many diferent types of actuators, sensors, mechanisms and architectures of the mechanical system to control, thus, by substituting a few modules we can obtain a flexible integration that answers to the needs of each case, without the need of a completely new control system, making the automation more simple,eficient and fast. As an example, in the automation of a robot, may be neccessary two computers, so that the data processing loads of control and the user's graphics interface processing load can be divided between these, but, in an application, like a vídeo camera positioning, the simplicity of the mechanical system, enables the use of only one computer, or even, a dedicated board, beeing keept the global structure of the control system / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Die kollaborative Teilebearbeitung mit Robotern und Werkzeugmaschinen wird in der Fertigung immer wichtiger. Durch die gleichzeitige Arbeit von Robotern und Werkzeugmaschinen kann eine noch effizientere Produktion erreicht werden. Mit der Entwicklung fortschrittlicher simulationsbasierter Lösungen können Hersteller jetzt die Zusammenarbeit von Robotern und Werkzeugmaschinen besser simulieren und überprüfen, um potenzielle Probleme zu erkennen und zu lösen, bevor sie in der realen Fertigung auftreten. Eine solche Lösung ist die NX-Offline-Simulation in Verbindung mit digitalen Zwillingen, mit der Hersteller ihre Teilebearbeitungsprogramme testen und optimieren können. Der Vortrag erläutert kurz das laufende Projekt 'RokoPro' und die Notwendigkeit des Einsatzes von Robotern in der Fertigung und der Simulation zur Überprüfung dieser Lösungen. / Collaborative part processing with robots and machine tools is becoming increasingly important in manufacturing. Even more efficient production can be achieved by having robots and machine tools work simultaneously. With the development of advanced Simulation-based solutions manufacturers can now better simulate and verify the collaboration of robots and machine tools to identify and solve potential problems before they occur in real manufacturing. One such solution is NX offline simulation along with digital twins, which allows manufacturers to test and optimize their part processing programs. The presentation briefly explains the ongoing project “RokoPro” and the need for use of robots in manufacturing and simulation to check those solutions.

The ability to handle and process data for information extraction is getting more and more important. Using extracted data from the business to improve productivity is seen as an important part in developing the business processes. In this thesis, industrial robots and their survival times are analyzed. The work is about predicting the probability that a specific robot will fail during a specified time period. Also, survival analysis is conducted where the median lifetime and conditional median lifetime for industrial robots are estimated. Two approaches are used, logistic regression and survival analysis. A logistic regression model is made to predict the probability for different industrial robots to break during a specified time period. The logistic model achieves an accuracy of 0.694 with even higher accuracy regarding high – and low risk robots. The survival analysis uses a Cox PH model to check validity for proportional hazards and then a parametric model with Weibull distribution is fitted. The parametrical survival model is used to estimate the median lifetime and the remaining median lifetime for the robots. The estimated probabilities and lifetimes can be used as an indication of which robots are in risk of failure.

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