doc. Ing. Jiří Krejsa, Ph.D.
E-mail:   krejsa@fme.vutbr.cz  Dept.:   Institute of Solid Mechanics, Mechatronics and Biomechanics Dept. of Mechatronics Position:   Associate Professor Room:   A2/720

Supervised courses:

• Artifical Inteligence (RAI)
• Introduction to Signal Processing (RSZ)
• Introduction to Signal Processing (RSZ-A)
• Kinematics (4KI)
• Kinematics (4KI-A)

Publications:

• RIPEL, T.; KREJSA, J.; HRBÁČEK, J.; ČIŽMÁŘ, I.:
  Active Elbow Orthosis, InTech Europe
  journal article in Web of Science
• RIPEL, T.; KREJSA, J.; HRBÁČEK, J.:
  Patient Activity Measurement in Active Elbow Orthosis,
  Mechatronics 2013, pp.817-824, ISBN 978-3-319-02293-2, (2013), Springer International Publishing
  conference paper
  akce: 10th International Conference on Mechatronics, Brno, 07.10.2013-09.10.2013
• KREJSA, J.; VĚCHET, S.; HRBÁČEK, J.; RIPEL, T.; ONDROUŠEK, V.; HRBÁČEK, R.; SCHREIBER, P.:
  Presentation robot Advee,
  Engineering Mechanics, Vol.18, (2012), No.5/6, pp.307-322, ISSN 1802-1484, Association for Engineering Mechanics
  journal article - other
• KREJSA, J.:
  Reduction of face detection false positives in mobile robot interaction using proximity sensors,
  Mendel 2011, pp.540-545, ISBN 978-80-214-4302-0, (2011)
  conference paper
  akce: 17th International Conference of Soft Computing, MENDEL 2011, Brno University of Technology, 15.06.2011-17.06.2011
• KREJSA, J.; VĚCHET, S.:
  MOBILE ROBOT MOTION PLANNER VIA NEURAL NETWORK,
  Engineering Mechanics 2011, 17th International conference may 9-12, 2011, Svratka, Czech republic, pp.227-230, ISBN 978-80-87012-33-8, (2011), Institute of Thermomechanics, Academy of Sciences of the Czech Republic
  conference paper
  akce: Engineering Mechanics 2011, Svratka, 09.05.2011-12.05.2011
• HRBÁČEK, J.; RIPEL, T.; KREJSA, J.:
  Ackermann mobile robot chassis with independent rear wheel drives,
  Proceedings of EPE-PEMC 2010, pp.T5-46-T5-51, ISBN 978-1-4244-7856-9, (2010)
  conference paper
  akce: 14th International Power Electronics and Motion Control Conference (EPE-PEMC) , Makedonie, 06.09.2010-08.09.2010
• RIPEL, T.; HRBÁČEK, J.; KREJSA, J.:
  Ackerman Steering chassis with independently driven back wheels,
  Proceedings of the 1st international conference Robotics in Education, RiE 2010, pp.127-132, ISBN 978-80-227-3353-3, (2010), Slovak University of Technology
  conference paper
  akce: Robotics in Education, Bratislava, 16.09.2010-17.09.2010
• KREJSA, J.; VĚCHET, S.; HRBÁČEK, J.; SCHREIBER, P.:
  High Level Software Architecture for Autonomous Mobile Robot,
  Recent Advances in Mechatronics 2008 - 2009, pp.185-190, ISBN 978-3-642-05021-3, (2009), Springer
  conference paper
  akce: Mechatronics 2009, Luhačovice, 18.11.2009-20.11.2009
• KREJSA, J.; VĚCHET, S.:
  Scan Matching Based SLAM - Dealing with Dynamic Obstacles,
  Modelling and Optimization of Physical Systems, pp.59-62, ISBN 978-83-60102-50-3, (2008)
  conference paper
  akce: 12th International Seminar of Applied Mechanics, Wisla, 13.06.2008-15.06.2008
• KREJSA, J.; VĚCHET, S.; HOUFEK, L.:
  GA In Shock Absorber Identification Task,
  Simulation Modelling of Mechatronic Systems III, pp.177-187, ISBN 978-80-214-3559-9, (2007), Brno University of Technology
  book chapter
• KREJSA, J.; HOUFEK, L.; VĚCHET, S.:
  The Influence of GA Initial Boundaries on the Identification of Nonlinear Damping Characteristics of Shock Absorber,
  Recent Advances in Mechatronics, pp.411-415, ISBN 978-3-540-73955-5, (2007), Springer
  conference paper
  akce: Mechatronics 2007, Warsaw, 19.09.2007-21.09.2007
• KREJSA, J.; VĚCHET, S.:
  Improving Rapidly Exploring Trees Method Using Two Trees,
  Book of Extended Abstracts, pp.186-187, ISBN 80-86246-27-2, (2006), Institute of Theoretical and Applied Mechanics
  conference paper
  akce: Engineering Mechanics 2006, Svratka, 15.05.2006-18.05.2006

List of publications at Portal BUT

Abstracts of most important papers:

• RIPEL, T.; KREJSA, J.; HRBÁČEK, J.; ČIŽMÁŘ, I.:
  Active Elbow Orthosis, InTech Europe
  journal article in Web of Science
  This paper presents a novel approach to the design of a motorized rehabilitation device – active elbow orthosis (AEO) – inspired by the principles of robotic exoskeletons. The device is currently designed for the elbow joint, but can be easily modified for other joints as well. AEO determines the motion activity of the patient using a strain gauge and utilizes this measurement to control the actuator that drives the forearm part of the orthosis. Patient activity level is related to a free arm measurement obtained via a calibration procedure prior to the exercise. A high-level control module offers several types of exercises mimicking the physiotherapist. The device was successfully verified by tests on a number of patients, resulting in extended range of elbow-joint motion.
• KREJSA, J.:
  Reduction of face detection false positives in mobile robot interaction using proximity sensors,
  Mendel 2011, pp.540-545, ISBN 978-80-214-4302-0, (2011)
  conference paper
  akce: 17th International Conference of Soft Computing, MENDEL 2011, Brno University of Technology, 15.06.2011-17.06.2011
  People detection is essential for mobile robots that are suppose to communicate with human. Face detector can be used as a primary tool for such detection. The paper presents a method of combining the face detector output with distance measurements provided by low cost proximity sensors. The method reduces the false positives given by face detector, thus preventing the robot from starting the conversation when the subject is not present. Data for fusion were taken from the measurements of mobile robot Advee in real world environment. Presented approach is easy to implement on variety of platforms and is computationally cheap. Verification tests were performed with the same robot and about 30 % reduction of false positives was obtained.
• KREJSA, J.; VĚCHET, S.; HRBÁČEK, J.; SCHREIBER, P.:
  High Level Software Architecture for Autonomous Mobile Robot,
  Recent Advances in Mechatronics 2008 - 2009, pp.185-190, ISBN 978-3-642-05021-3, (2009), Springer
  conference paper
  akce: Mechatronics 2009, Luhačovice, 18.11.2009-20.11.2009
  The paper deals with the high level software architecture for autonomous mobile robot Bender II, medium size wheeled nonholonomic mobile robot with Ackerman chassis for both indoor/outdoor environment. High level software uses hybrid approach combining common layered architecture with reactive control. Local navigation including static/dynamic obstacle detection/avoidance is based on laser range finder data. Global navigation in indoor environment is based on fusion of odometry based position estimation with precomputed scan matching localization technique. Architecture description is accompanied by tests results ob-tained in real environment.
• KREJSA, J.; VĚCHET, S.:
  Scan Matching Based SLAM - Dealing with Dynamic Obstacles,
  Modelling and Optimization of Physical Systems, pp.59-62, ISBN 978-83-60102-50-3, (2008)
  conference paper
  akce: 12th International Seminar of Applied Mechanics, Wisla, 13.06.2008-15.06.2008
  Localization and mapping is essential task in autonomous mobile robotics. There is a number of methods dealing with the task. The method called Potential-Based Scan Matching uses proximity sensor data and does not require the odometry readings for successful localization. The method is resistant towards the noise in proximity sensors. The paper is focused on testing the method in dynamically changing environment. Tests were performed for variable size of obstacles and speed of its motion.
• KREJSA, J.; HOUFEK, L.:
  IDENTIFICATION OF SHOCK ABSORBER NONLINEAR MODEL CHARACTERISTICS,
  1, pp.99-102, ISBN 83-60102-30-9, (2006), Wydawnictvo Katedry Mechaniki Stosowanej
  conference paper
  akce: 10th International seminar of Applied Mechanics, Wisla, 16.06.2006-18.06.2006
  The paper shows the possible way of identification of shock absorber nonlinear model characteristics using genetic algorithm. 2 DOF quarter car model is used with nonlinear characteristics of main spring and damping forces defined as piecewise functions. Using time courses of position, velocity and acceleration of both masses under kinematic excitation the characteristics are found. Simulation results are satisfactory.