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Morales, Daniel Ortiz
Alternative names
Publications (10 of 14) Show all publications
La Hera, P. & Morales, D. O. (2015). Model-Based Development of Control Systems for Forestry Cranes. Journal of Control Science and Engineering, 2015, Article ID 256951.
Open this publication in new window or tab >>Model-Based Development of Control Systems for Forestry Cranes
2015 (English)In: Journal of Control Science and Engineering, ISSN 1687-5249, E-ISSN 1687-5257, Vol. 2015, article id 256951Article in journal (Refereed) Published
Abstract [en]

Model-based methods are used in industry for prototyping concepts based on mathematical models. With our forest industry partners, we have established a model-based workflow for rapid development of motion control systems for forestry cranes. Applying this working method, we can verify control algorithms, both theoretically and practically. This paper is an example of this workflow and presents four topics related to the application of nonlinear control theory. The first topic presents the system of differential equations describing the motion dynamics. The second topic presents nonlinear control laws formulated according to sliding mode control theory. The third topic presents a procedure for model calibration and control tuning that are a prerequisite to realize experimental tests. The fourth topic presents the results of tests performed on an experimental crane specifically equipped for these tasks. Results of these studies show the advantages and disadvantages of these control algorithms, and they highlight their performance in terms of robustness and smoothness.

National Category
Robotics Control Engineering
Identifiers
urn:nbn:se:umu:diva-112787 (URN)10.1155/2015/256951 (DOI)000361955200001 ()
Available from: 2015-12-14 Created: 2015-12-14 Last updated: 2018-06-07Bibliographically approved
Ortiz Morales, D., La Hera, P., Westerberg, S., Freidovich, L. & Shiriaev, A. (2015). Path-constrained motion analysis: an algorithm to understand human performance on hydraulic manipulators. IEEE Transactions on Human-Machine Systems, 45(2), 187-199
Open this publication in new window or tab >>Path-constrained motion analysis: an algorithm to understand human performance on hydraulic manipulators
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2015 (English)In: IEEE Transactions on Human-Machine Systems, ISSN 2168-2291, Vol. 45, no 2, p. 187-199Article in journal (Refereed) Published
Abstract [en]

We propose a novel method to analyze how human operators use hydraulic manipulators of heavy-duty equipment. The approach is novel in the sense that it applies knowledge of motion planning and optimization techniques used in robotics. As an example, we consider the case of operating a forestry crane. To that end, we use motion data that has been recorded during standard operation with the help of sensors and a data acquisition unit. The data backs up the notion that operators work by performing repeatable patterns observed in the trajectories of the manipulator's joints. We show how this nominal behavior is computed, and consequently this allow us to present the following: 1) an analytical procedure to analyze motions, 2) how to represent the "performance" of the operator in a 2D plot, 3) an example of how to use this information to suggest customized control settings, and 4) some complementary ideas needed for improving efficiency through automation.

Keywords
forestry, human performance analysis, hydraulic manipulators, manual control
National Category
Robotics Control Engineering
Identifiers
urn:nbn:se:umu:diva-87595 (URN)10.1109/THMS.2014.2366873 (DOI)000351468500004 ()
Available from: 2014-04-04 Created: 2014-04-04 Last updated: 2018-06-08Bibliographically approved
Ortiz Morales, D. (2015). Virtual Holonomic Constraints: from academic to industrial applications. (Doctoral dissertation). Umeå: Umeå Universitet
Open this publication in new window or tab >>Virtual Holonomic Constraints: from academic to industrial applications
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Whether it is a car, a mobile phone, or a computer, we are noticing how automation and production with robots plays an important role in the industry of our modern world. We find it in factories, manufacturing products, automotive cruise control, construction equipment, autopilot on airplanes, and countless other industrial applications.

        Automation technology can vary greatly depending on the field of application. On one end, we have systems that are operated by the user and rely fully on human ability. Examples of these are heavy-mobile equipment, remote controlled systems, helicopters, and many more. On the other end, we have autonomous systems that are able to make algorithmic decisions independently of the user.

        Society has always envisioned robots with the full capabilities of humans. However, we should envision applications that will help us increase productivity and improve our quality of life through human-robot collaboration. The questions we should be asking are: “What tasks should be automated?'', and “How can we combine the best of both humans and automation?”. This thinking leads to the idea of developing systems with some level of autonomy, where the intelligence is shared between the user and the system. Reasonably, the computerized intelligence and decision making would be designed according to mathematical algorithms and control rules.

        This thesis considers these topics and shows the importance of fundamental mathematics and control design to develop automated systems that can execute desired tasks. All of this work is based on some of the most modern concepts in the subjects of robotics and control, which are synthesized by a method known as the Virtual Holonomic Constraints Approach. This method has been useful to tackle some of the most complex problems of nonlinear control, and has enabled the possibility to approach challenging academic and industrial problems. This thesis shows concepts of system modeling, control design, motion analysis, motion planning, and many other interesting subjects, which can be treated effectively through analytical methods. The use of mathematical approaches allows performing computer simulations that also lead to direct practical implementations.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2015. p. 57
Series
Robotics and control lab, ISSN 1654-5419 ; 7
Keywords
Virtual Holonomic Constraints, modeling, control, motion planning, under-actuated systems, forestry cranes, hydraulic manipulators
National Category
Control Engineering Robotics
Identifiers
urn:nbn:se:umu:diva-87707 (URN)978-91-7601-196-6 (ISBN)
Public defence
2015-02-02, MA121, MIT-Huset, Umeå Universitet, Umeå, 13:00 (English)
Opponent
Supervisors
Available from: 2015-01-12 Created: 2014-04-07 Last updated: 2018-06-07Bibliographically approved
Ortiz Morales, D., Westerberg, S., La Hera, P., Mettin, U., Freidovich, L. & Shiriaev, A. (2014). Increasing the level of automation in the forestry logging process with crane trajectory planning and control. Journal of Field Robotics, 31(3), 343-363
Open this publication in new window or tab >>Increasing the level of automation in the forestry logging process with crane trajectory planning and control
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2014 (English)In: Journal of Field Robotics, ISSN 1556-4959, E-ISSN 1556-4967, Vol. 31, no 3, p. 343-363Article in journal (Refereed) Published
Abstract [en]

Working with forestry machines requires great amount of training to be sufficiently skilledto operate forestry cranes. In view of this, introducing automated motions, as those seenin robotic arms, is ambitioned by this industry for shortening the amount of training timeand make the work of the operator easier. Motivated by this fact, we have developedtwo experimental platforms for testing control systems and motion planning algorithms inreal-time. They correspond to a laboratory setup and a commercial version of a hydraulicmanipulator used in forwarder machines. The aim of this article is to present the results ofthis development by providing an overview of our trajectory planning algorithm and motioncontrol method, with a subsequent view of the experimental results. For motion control,we design feedback controllers that are able to track reference trajectories based on sensormeasurements. Likewise, we provide arguments to design controllers in open-loop for thecase of machines lacking of sensing devices. Relying on the tracking efficiency of thesecontrollers, we design time efficient reference trajectories of motions that correspond tologging tasks. To demonstrate performance, we provide an overview of an extensive testingdone on these machines.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2014
Keywords
tree harvesting systems; robotic manipulators; excavator; industrialization
National Category
Robotics Control Engineering
Identifiers
urn:nbn:se:umu:diva-86214 (URN)10.1002/rob.21496 (DOI)000333934200001 ()
Available from: 2014-04-04 Created: 2014-02-20 Last updated: 2018-06-08Bibliographically approved
La Hera, P. & Ortiz Morales, D. (2014). Non-linear dynamics modelling description for simulating the behavior of forestry cranes. International journal of Modeling, identification and control, 21(2), 125-138
Open this publication in new window or tab >>Non-linear dynamics modelling description for simulating the behavior of forestry cranes
2014 (English)In: International journal of Modeling, identification and control, ISSN 1746-6172, E-ISSN 1746-6180, Vol. 21, no 2, p. 125-138Article in journal (Refereed) Published
Abstract [en]

Model-based design is a standard framework widely adopted in modern industry. It is used for designing multi-domain engineering solutions based on computer-aided simulation technology. Currently, this approach is also being viewed as a tentative method for designing modern heavy-duty machine technology. Under this motivation, our aim is to present how modeling techniques can be used for simulating dynamics of forestry machines. To this end, we consider a forestry crane, and propose mathematical models and calibration techniques, such that model-based methods can subsequently be applied. The complexity of the machine is represented by first principle laws, in which the mechanical system is modeled by Euler-Lagrange formulations, and the hydraulic system is modeled by principles of fluid dynamics. The calibration algorithms are performed by statistical algorithms based on linear and nonlinear least-squares methods. The results of simulation show a significant correspondence between the simulated and observed variables, validating our procedures.

Place, publisher, year, edition, pages
Inderscience Enterprises Ltd, 2014
Keywords
forestry machines, forestry cranes, hydraulic manipulators, dynamic modelling, model calibration, identification, simulation, real–time implementation, nonlinear dynamics, heavy–duty machinery, mathematical modelling, Euler–Lagrange formulations, fluid dynamics
National Category
Control Engineering Robotics
Identifiers
urn:nbn:se:umu:diva-87577 (URN)10.1504/IJMIC.2014.060006 (DOI)
Available from: 2014-04-04 Created: 2014-04-04 Last updated: 2018-06-08Bibliographically approved
Ortiz Morales, D., La Hera, P. & Ur Rehman, S. (2013). Generating Periodic Motions for the Butterfly Robot. In: Amato, N. (Ed.), Intelligent Robots and Systems (IROS), 2013 IEEE/RSJ International Conference on: . Paper presented at IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) Location: Tokyo, Japan Date: Nov 3-8, 2013 (pp. 2527-2532). IEEE conference proceedings
Open this publication in new window or tab >>Generating Periodic Motions for the Butterfly Robot
2013 (English)In: Intelligent Robots and Systems (IROS), 2013 IEEE/RSJ International Conference on / [ed] Amato, N., IEEE conference proceedings, 2013, p. 2527-2532Conference paper, Published paper (Refereed)
Abstract [en]

We analyze the problem of dynamic non-prehensile manipulation by considering the example of thebutterfly robot. Our main objective is to study the problem of stabilizing periodic motions, which resemble some form of juggling acrobatics. To this end, we approach the problem by considering theframework of virtual holonomic constraints. Under this basis, we provide an analytical and systematic solution to the problems of trajectory planning and design of feedback controllers to guarantee orbital exponential stability. Results are presented in the form of simulation tests.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2013
Series
IEEE International Conference on Intelligent Robots and Systems, ISSN 2153-0858
Keywords
Underactuated mechanical systems, limit cycles, virtual holonomic constraints, transverse linearization
National Category
Robotics
Identifiers
urn:nbn:se:umu:diva-86210 (URN)10.1109/IROS.2013.6696712 (DOI)000331367402100 ()978-1-4673-6358-7 (ISBN)
Conference
IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) Location: Tokyo, Japan Date: Nov 3-8, 2013
Available from: 2014-02-20 Created: 2014-02-20 Last updated: 2018-06-08Bibliographically approved
Ortiz Morales, D. & La Hera, P. X. (2012). Design of energy efficient walking gaits for a three-link planar biped walker with two unactuated degrees of freedom. In: Robotics and Automation (ICRA), 2012 IEEE International Conference on: . Paper presented at 2012 IEEE International Conference on Robotics and Automation (ICRA), Location: St Paul, MN, Date: May 14-18, 2012 (pp. 148-153). New York: IEEE Computer Society
Open this publication in new window or tab >>Design of energy efficient walking gaits for a three-link planar biped walker with two unactuated degrees of freedom
2012 (English)In: Robotics and Automation (ICRA), 2012 IEEE International Conference on, New York: IEEE Computer Society, 2012, p. 148-153Conference paper, Published paper (Other academic)
Abstract [en]

We consider the example of a three-link planar biped walker with two passive links. The main objective is to design symmetric periodic gaits in flat ground, that can be exponentially stabilized by feedback control. To this end, we apply recent advances in nonlinear control, to propose a systematic procedure to the problems of gait synthesis and control design. The core of the method lays on a nontrivial coordinate transformation, in order to approach the problem in a state-dependent form. For gait synthesis, such procedure allows a reduction of the search space, with the feasibility of considering energetic performance for optimization. For control design, this allows to apply concepts of transverse linearization, to design a nonlinear feedback control law, which performance is studied by numerical simulations.

Place, publisher, year, edition, pages
New York: IEEE Computer Society, 2012
Series
IEEE International Conference on Robotics and Automation, ISSN 2152-4092
Keywords
Walking robots, underactuated mechanical systems, limit cycles, virtual holonomic constraints, transverse linearization
National Category
Computer Sciences Robotics
Identifiers
urn:nbn:se:umu:diva-61582 (URN)10.1109/ICRA.2012.6224874 (DOI)000309406700023 ()978-1-4673-1405-3 (ISBN)
Conference
2012 IEEE International Conference on Robotics and Automation (ICRA), Location: St Paul, MN, Date: May 14-18, 2012
Available from: 2012-11-27 Created: 2012-11-20 Last updated: 2018-06-08Bibliographically approved
Ortíz Morales, D. & La Hera, P. X. (2012). Design of stable walking gaits for biped robots with several underactuated degrees of freedom. In: Dynamic Walking Conference 2012, Pensacola, Florida, U.S.A.: . Paper presented at Dynamic Walking Conference 2012, Pensacola, Florida, U.S.A. 21 - 25 May 2012.
Open this publication in new window or tab >>Design of stable walking gaits for biped robots with several underactuated degrees of freedom
2012 (English)In: Dynamic Walking Conference 2012, Pensacola, Florida, U.S.A., 2012Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

Dynamic walking gaits are theoretically reflected by theperiodic solutions exhibited by nonlinear impulsive dynamicalsystems [1]. In practice, such solutions, knownas limit cycles, can exist either as a natural responseof the system, e.g. passive walkers, or by the use offeedback control. Analytically, finding these solutionsis certainly challenging, and the complexity of the problemincreases considerably if a mixture in between passiveand actuated joints are considered, i.e. underactuatedrobots.

National Category
Robotics
Identifiers
urn:nbn:se:umu:diva-61880 (URN)
Conference
Dynamic Walking Conference 2012, Pensacola, Florida, U.S.A. 21 - 25 May 2012
Available from: 2012-11-29 Created: 2012-11-28 Last updated: 2018-06-08Bibliographically approved
La Hera, P., Rehman, B. U. & Morales, D. O. (2012). Electro-hydraulically actuated forestry manipulator: Modeling and Identification. In: 2012 IEEE/RSJ Iinternational Conference on Intelligent Robots and Systems (IROS): . Paper presented at 25th IEEE\RSJ International Conference on Intelligent Robots and Systems (IROS), OCT 07-12, 2012, Algarve, Portugal (pp. 3399-3404). New York: IEEE conference proceedings
Open this publication in new window or tab >>Electro-hydraulically actuated forestry manipulator: Modeling and Identification
2012 (English)In: 2012 IEEE/RSJ Iinternational Conference on Intelligent Robots and Systems (IROS), New York: IEEE conference proceedings, 2012, p. 3399-3404Conference paper, Published paper (Refereed)
Abstract [en]

We present results of modeling dynamics of a forestry manipulator, in which we consider its mechanics, as well as its hydraulic actuation system. The mathematical model of its mechanics is formulated by Euler-Lagrange equations, for which the addition of friction forces is straightforward. Dynamics of the hydraulic system is modeled upon first principle laws, which concern flow through orifices and fluid compressibility. These models lead to a set of equations with various unknown parameters, which are related to the inertias, masses, location of center of masses, friction forces, and valve coefficients. The numerical values of these parameters are estimated by the use of least-square methods, which is made feasible by transforming the models into linear representations. The results of simulation tests show a significant correspondence between measured and estimated variables, validating our modeling and identification approach.

Place, publisher, year, edition, pages
New York: IEEE conference proceedings, 2012
Series
IEEE International Conference on Intelligent Robots and Systems, ISSN 2153-0858
National Category
Robotics
Identifiers
urn:nbn:se:umu:diva-72717 (URN)10.1109/IROS.2012.6385656 (DOI)000317042703152 ()978-1-4673-1736-8 (ISBN)
Conference
25th IEEE\RSJ International Conference on Intelligent Robots and Systems (IROS), OCT 07-12, 2012, Algarve, Portugal
Available from: 2013-06-10 Created: 2013-06-10 Last updated: 2018-06-08Bibliographically approved
La Hera, P. X. & Ortíz Morales, D. (2012). Modeling dynamics of an electro-hydraulic servo actuated manipulator: A case study of a forestry forwarder crane. In: World Automation Congress (WAC), 2012: . Paper presented at World Automation Congress (WAC) 2012, 24-28 June 2012, Puerto Vallarta, Mexico.
Open this publication in new window or tab >>Modeling dynamics of an electro-hydraulic servo actuated manipulator: A case study of a forestry forwarder crane
2012 (English)In: World Automation Congress (WAC), 2012, 2012Conference paper, Published paper (Refereed)
Abstract [en]

System modeling and parameters estimation are key elements to realize model-based control. Here, we present a discussion of modeling dynamics of a forestry forwarder crane, for which standard Euler-Lagrange formulations are used to describe its equations of motion. To calibrate this model according to experimental data, we perform parameter estimation based on the method of least squares. This procedure allows identifying various unknown parameters, which are related to the inertias, masses, location of center of masses, and friction forces coefficients. The results of simulation tests show a significant correspondence between measured and estimated variables, validating our modeling approach.

Series
World Automation Congress proceedings, ISSN 2154-4824
National Category
Robotics
Identifiers
urn:nbn:se:umu:diva-61826 (URN)978-1-4673-4497-5 (ISBN)
Conference
World Automation Congress (WAC) 2012, 24-28 June 2012, Puerto Vallarta, Mexico
Available from: 2012-11-28 Created: 2012-11-26 Last updated: 2018-06-08Bibliographically approved
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