http://www.ifac-papersonline.net/ en Copyright 01:25 PM Thursday 17, 2012 IFAC-PapersOnline http://www.ifacpapersonline.com 01:25 PM Thursday 17, 2012 01:25 PM Thursday 17, 2012 ET webmaster@ifac-papersonline.net webmaster@ifac-papersonline.net http://www.ifac-papersonline.net/Detailed/25254.html 04:00 PM Wednesday 31, 1969 This paper describes applications of a new kind of unconventional high performance piezoelectric actuator with extraordinary electromechanical coupling (actuator and sensor capabilities), high flexibility, an extremely robust monolithic structure and a high damage tolerance. This is due to the special set-up where unidirectional piezoelectric fibres are energized by a pair of interdigital electrode assemblies. The quasimonolithic structure allows for outstanding mechanical and electrical properties. The special material combination serves the purposes of mechanical stabilisation, good flexibility, high temperature tolerance and maximum achievable adhesion, thus allowing for a complete integration into e.g. carbon reinforced plastics without massive weakening of the load bearing structure. The unique properties of the new actuator together with technical advances in control capabilities are important steps towards a smart material system. The used control algorithm can easily be adapted to different applications for that a versatile solution of active vibration control together with in-situ monitoring of mechanical loads, vibrations or impacts can be realized. Besides flexibility and high robustness the actuators exhibit a low power demand and can be used excellently for energy harvesting. The main objectives of a smart mechatronic system are: realization of active and lightweight constructions, adaptivity to unpredictable service conditions, high robustness, self-diagnostic abilities, high functionality density as well as low power demand and energy harvesting. The most promising active/adaptive materials to meet these objectives are piezoelectric fibre composites (PFC). The presentation will give an overview about mechatronic applications for such unconventional actuators like integration into structures, active vibration reduction, modal analysis, generation of ultrasonic waves and energy harvesting, respectively. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25338.html 04:00 PM Wednesday 31, 1969 The robot localization is an important problem in mobile robotics. This work addresses the problem of global localization in indoor environment by using vision-based technique. This paper proposes innovative idea of using the 3D artificial landmark and the 3D Photonic Mixer Device (PMD) camera for robot localization. Since the 3D camera provides a ready-to-use depth image, there is no extra effort needed to enable the computation of 3D image reconstruction as in stereo vision system and also the range image from PMD camera can be obtained under very low visibility condition. The design of the 3D landmark and the recognition technique can be applicable for other range sensors. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25320.html 04:00 PM Wednesday 31, 1969 This paper describes a behaviour-based navigation system for airborne autonomous robots. The work has been validated by controlling an indoor blimp with a finite-state machine. It is shown that behaviour-based navigation, especially concerning mobile robots for indoor applications, is predestined to perform reconnaissance of unknown areas and moreover for navigation tasks in familiar environment. Due to the inability of most autonomous indoor aerial vehicles to carry heavy sensors, these systems lack of metrical information and therefore the explicit localization is yet impossible until today. The behaviour-based navigation is combined with a variety of path-planning methods (tree-search, potential fields, etc.) using obstacle-maps of known surroundings enabling the robot to acquire a desired position in a correspondent cluster of rooms. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25207.html 04:00 PM Wednesday 31, 1969 This paper describes a hierarchical architecture for rhythmic coordination between robots, which suits a juggling-like ball passing task involving sensorymotor coordination. The proposed architecture contains two passive-control mechanisms, which include (1) open-loop stability of mechano-physical system and (2) entrainment between mechano-physical system and neuron-like pattern generating system. We demonstrate a stable coordinated motion of robots in the two-ball passing task, and show the effectiveness of our approach which exploits system dynamics caused by the interaction between the envirnment and the robots. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25262.html 04:00 PM Wednesday 31, 1969 A service robot for a domestic environment should be able to grasp, move, and release objects. To successfully grasp objects that cannot be expected to be perfectly modelled and whose positions are not exactly known, control algorithms need to handle uncertainty. Such controllers often use information from force/torque, tactile and joint angle sensors. This paper presents a simulation environment and proposes a design approach for controlling robotic grasping under those conditions. Finally, results from simulation of a sample task are presented. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25296.html 04:00 PM Wednesday 31, 1969 The purpose of this paper is to develop a hexapod robot that uses shape memory alloy (SMA) actuators. The design of the robot follows a bio-mimetic approach. This paper first discusses various gaits for six-legged motion. The paper then introduces the characteristics of the SMA actuator and the corresponding driver design. The robot motion controller is implemented with an ARM9 based embedded system. Finally, the test results are presented and the robot performance is discussed. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25226.html 04:00 PM Wednesday 31, 1969 State of the art high speed color printers require sheets be accurately positioned as they arrive at the image transfer station. To accomplish this goal, a steerable nips mechanism has been designed and built. This mechanism is located upstream from the image transfer station. This steerable nips mechanism allows sheets to be precisely controlled in the longitudinal, lateral, and skew directions. In this paper we present the design, sensing strategy, and a control law based on state feedback linearization. Simulation and experimental results show that the proposed controller is able to correct for paper position errors in the above mentioned directions under the condition that the sheet has nonzero initial and final velocities. The system model is nonlinear and subject to four nonholonomic constraints. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25303.html 04:00 PM Wednesday 31, 1969 The evolution of ground transportation power sources from internal combustion engines to a hybrid architecture featuring a fuel cell stack and electric drives necessitates the re-design of the traditional cooling system. The common thermostat and mechanical pump are replaced by smart valves, variable speed pumps, and adjustable radiator fans. In the fuel cell, multiple cooling zones are proposed using servo-motor components to better regulate the temperature and moisture levels as prescribed by the operating conditions. In this paper, multiple thermal loops and dynamic models for a fuel cell cooling system will be presented. A scale experiment, emulating the main fuel cell cooling loop, validated the models and demonstrated temperature tracking capabilities. The coolant temperature was maintained in a ±1.5°C neighborhood of the set point. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25183.html 04:00 PM Wednesday 31, 1969 This paper presents a LiGA (German acronym for LIthografie, Galvanoformung, Abformung) based micro biopsy actuator for the capsular endoscope. The proposed fabricated actuator aims to extract sample tissues inside small gastric intestines, that cannot be reached by conventional biopsy. The actuator size is 10 mm in diameter and 1.8 mm in length. The mechanism is of a slider-crank type. The actuator consists of trigger, rotational module, and micro biopsy tool. The core components are fabricated using the LiGA process, for overcoming the limitations in accuracy of conventional precision machining. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25291.html 04:00 PM Wednesday 31, 1969 This paper is aimed to design a zero-power controller based on the theoretical model and to implement it into a vibration isolation system. To develop the vibration isolation system which is able to isolate ground vibrations as well as to suppress direct disturbance, a positive passive suspension is connected in series with an active negative spring at the outset. The system is further reinforced by using a weight support mechanism to enhance the performance for supporting heavy payloads and/or developing large isolation table. The characteristic of the developed system is treated analytically and the efficacy of the controller performances is verified experimentally. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25331.html 04:00 PM Wednesday 31, 1969 A prototype of a monitor-based augmented reality (AR) system is presented in this paper. The system is completely mobile, consisting of a motorized controllable camera and a laptop with a head set. The human-system interaction is realized by user-oriented interfaces and is speech-based. Advantages of the system are its simplicity and low cost combined with proven usability. Compared to other present tools for presentation of instructions for maintenance and operation, the use of this system results in time savings and lower error rates, as shown by experiments undertaken at the IPP. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25307.html 04:00 PM Wednesday 31, 1969 Inspired by learning feed-forward control structures, this paper considers the adaptation of the parameters of a model-reference based learning feed-forward controller that realizes an inverse model of the process. The actual process response is determined by a setpoint generator. For linear systems it can be proved that the controlled system is asymptotically stable in the sense of Liapunov. Compared with more standard model reference configurations this system has a superior performance. It is fast, robust and relatively insensitive for noisy measurements. Simulations with an arbitrary second-order process and with a model of a typical fourth-order mechatronics process demonstrate this. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25210.html 04:00 PM Wednesday 31, 1969 The side-stepping maneuver of the triple inverted pendulum serves as a benchmark problem for the presentation of a new feedforward control design approach for finite-time transition problems under consideration of output constraints. The inversion-based design treats the transition task as a two-point boundary value problem (BVP) defined in the input-output coordinates of the pendulum model. The new approach allows to directly incorporate constraints of the output and its time derivatives within the BVP, which is solved by a standard Matlab function. A linear LQR controller is used to stabilize the pendulum along the feedforward side-stepping trajectories. Simulation and experimental results for the triple inverted pendulum illustrate the accuracy and robustness of the proposed feedforward/feedback control scheme. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25185.html 04:00 PM Wednesday 31, 1969 The prostate is a small exocrine gland in men responsible for production of the liquid component of the seminal fluid. In North America, prostate cancer accounts to over 300,000 new cases and 40,000 deaths each year and it is the second leading cause of cancer death in men. Low-dose Rate (LDR) brachytherapy is gaining interest as a viable treatment option for prostate cancer due to its low side effects and high benefits. This procedure involves insertion of small seeds of radioactive isotopes into the gland to effect radiation therapy. The present manual approach for needle insertion and the inherent flexibility of brachytherapy needles makes it extremely difficult to achieve accurate and consistent dosimetry. In this paper, we present the design of a new 5 DOF manipulator capable of performing percutaneous needle insertion. The manipulator can perform orientation, insertion and rotation of the needle and linear motion of the plunger to drop radioactive seeds at targeted locations. Some of the key features of the manipulator are backdrivable joints, stationary actuators, redundant sensors and enhanced safety features. The manipulator will become an integral part of a system utilizing real-time 3D ultrasound image guided prostate brachytherapy. In this paper, we describe the mechanical design, construction and assembly of the manipulator. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25325.html 04:00 PM Wednesday 31, 1969 This paper deals with a data fusion algorithm for wheeled mobile robot localization using data from multiple localization systems. One is dead reckoning, which is subject to different systematic and random errors, summing up over time. Still, it offers high resolution in the close-up range and by data fusion with a landmark-based low resolution localization system qualifies for high accuracy path control. Here a data fusion algorithm is developed, which chooses the more reliable data source providing smooth transitions. Furthermore the system makes use of time spans when the availability of both systems is high to improve the quality of the position estimation. The parameters of the error correction algorithm are continuously estimated by a recursive least squares algorithm. The methodology is applied to a 4-wheel omnidirectional wmr. A significant improvement of precision in position estimation against simple dead reckoning can be shown. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25284.html 04:00 PM Wednesday 31, 1969 One of the main issues of any control strategy for braking systems is to face the many uncertainties due to the strong spread of the system's parameters: road conditions, actuator dynamics, tire behaviour, etc. This paper proposes a self-tuning control for an electromechanical braking system. Electromechanical brake system is a promising replacement for hydraulic brakes in the automotive industry. The proposed control can be seen as a minimum seek algorithm in a highly uncertain situation. Only the measure of the wheel angular speed and a rough measure (or estimate) of the actuator force on the brake pads are required. The proposed control is tested by simulation studies. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25335.html 04:00 PM Wednesday 31, 1969 This article deals with the trajectory tracking problem for the angular velocity of a dc-motor shaft using a Boost-converter as the switch regulated electronic drive. The main result of our proposed control scheme is that measuring of the angular velocity is not really necessary and the control law is synthesized using only a linear time-varying combination of the converter current and voltage variables. The voltage reference trajectory for the converter is generated exploiting a partial differential flatness property of the combined system. The reference trajectories of the average control and the input current are calculated via stored energy considerations and planning for the initial and final stationary regimes. The discrete switching control realization of the designed continuous feedback control law is accomplished by means of a traditional PWM-modulation scheme. Experimental results are provided. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25191.html 04:00 PM Wednesday 31, 1969 Audi dynamic steering is a safety relevant electronic steering system. In order to achieve functional safety for this system a structured development process including all safety process aspects and several support processes have been defined and installed. Furthermore, the compliance of the implemented processes with the defined processes is strictly monitored by the internal quality assurance. Additionally, an external assessor is accompanying the product development in order to assure the functional safety of the product according to the requirements of international safety standards. Besides the enforcement of the processes, the challenge in this project is the coordination and monitoring of three suppliers together with the quality assurance and the external assessor. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25288.html 04:00 PM Wednesday 31, 1969 In this article, a Generalized Predictive Control (GPC) is used to perform the active damping of a structure with sloshing phenomena. The studied flexible structure has been designed to have the same dynamic behavior than an aircraft wing (the first bending mode has a frequency of 1.59 Hz). It is composed by a free-clamped beam and a tank and is equipped with piezoelectric actuators. The purposes here are on the one hand to perform the damping of the structure i.e. to perform as efficiently as possible the vibratory disturbances rejection and on the other hand to evaluate the performances of the GPC control law, in the domain of flexible structures. The first part of the article deals with the sizing and the modeling of the active structure using the Lagrangian approach and a FEM software. The second part concerns the control law. The used control law - i.e. GPC - has been chosen because of its good control performances, its compactness and its robustness in front of model mismatches. These advantages are particularly interesting in this study, because the control must be performed for several levels of filling of the tank, in a MIMO, multimodes context. Experiments have been performed (for the control of the first bending mode and the control of the first bending and twisting modes). In each case, GPC is efficient. Moreover, the use of GPC leads to a unique global behavior for the controlled structure, whatever the tank's filling configuration may be. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25193.html 04:00 PM Wednesday 31, 1969 This paper concerns active fault-tolerant control (FTC) for unstable systems. A major obstacle to this problem is that the time delay between the fault appears and the FTC controller becomes active may destabilize the system. In this paper, an active FTC scheme based on gain-scheduled H-infinity controller and neural network is proposed. Under the assumption that the effects of faults on system matrices can be of affine parameter dependence, a reconfigurable robust H-infinity controller is developed, which is a function of the fault effect factors that can be derived on-line from the residual vector of the fault detection and isolation (FDI) mechanism. The proposed method is used for successful FTC control of a double inverted pendulum system with a fault in the tachometer loop of the motor. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25326.html 04:00 PM Wednesday 31, 1969 In interacting of a human being with machines and processes haptic feedback offers new potential. A haptic display gives either a realistic reproduction of feel to the user, like in teleoperating applications, or it renders artificial effects from a virtual reality scenario. A special, highly demanding case is vehicle or aircraft control often referred to as x-by-wire. There are common requirements for all types of force-feedback devices like high accuracy, high dynamics, excellent controllability or high power density. An electro mechanic servo actuator combined with a Harmonic Drive gear gives a good start for setting up a solution. But for further improvement it is worth to have a closer look at both, the HD gear as a single component and its specific behaviour within the mechatronic system, for key aspects like design, reliability, sensor integration, data acquisition and processing. This paper will report distinctive features of force-feedback applications using Harmonic Drive gears, summarise experiences and enumerates some customer's solutions in academic research or being available on the market. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25244.html 04:00 PM Wednesday 31, 1969 This paper presents a new active roll control device. This device uses an original hydraulic actuator, based on two tandem pumps, designed to be used in addition of a reduced anti-roll bar. The actuator control strategy is also original. It is based on hierarchical and hybrid control with a supervisor, a feedforward and a feedback loop whose robust controller is synthesized thanks to the CRONE control methodology. Because of the severe specifications sheets in term of power consumption, the simulated performances are thus limited but interesting. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25290.html 04:00 PM Wednesday 31, 1969 This paper presents active vibration damping of a hydrostatically supported, flexible structure. The objective is to show the capability of active hydrostatic bearings, where the flow rate is controlled by using a fast, dynamic servo valve. To achieve high control performance the robust control concept µ-synthesis is applied successfully. It enables to overcome undesirable properties of the mechatronic system as, weakly damped, low frequency flexible modes, phase lag, slight nonlinearities or non-collocation. For the investigations two test rigs, a rigid mass and a flexible beam, both supported by active hydrostatic bearings are presented. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25189.html 04:00 PM Wednesday 31, 1969 This paper is concerned with the adaptive backstepping sliding-mode control of nonlinear dynamic systems with model uncertainties. The proposed control method suitable for mechatronic systems combines the advantages of sliding-mode control and backstepping methodology, such that the requirement of the matching condition is removed, which seriously clams the application of sliding-mode control. In the control scheme, networks of Gaussian radial basis functions with variable weights are used to compensate the model uncertainties. The adaptive law developed using the Lyapunov synthesis approach guarantees the stability of the control scheme. The performance is illustrated by experimental studies with a flexible-joint manipulator. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/25308.html 04:00 PM Wednesday 31, 1969 Considering rather severe parametric uncertainties and nonlinear uncertainties exist in the dynamic model of pneumatic muscles driven parallel manipulator, a discontinuous projection-based adaptive robust control strategy (ARC) is adopted to effectively handle the effect of various parameter variations of the system and hard-to-model nonlinearities such as the friction forces of the pneumatic muscles and external disturbances of the entire pneumatic system to achieve remarkably precise posture trajectory control. Experimental results are obtained to illustrate the effectiveness of the proposed adaptive robust controller. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif