Malaga

This paper develops a novel approach to combining probabilistic motion planners. Rather than trying to develop a single planner that works over a wide range of environments, we develop a strategy for combining different motion planners within a single framework. Specifically we examine how planners designed for open spaces and those designed for narrow passages can be integrated within a single planning framework. Information that is normally discarded in the planning process is used to identify regions as being potentially 'narrow' or 'cluttered', and we then apply the planner most suited for that region based on this information. Experimental results demonstrate our approach outperforms the basic PRM approach as well as a Gaussian sampler designed for narrow regions in three test environments.

The development of mechatronic products - in particular across the domain borders - is challenging. Possible interdisciplinary improvements are neglected and design inconsistencies are neither prevented nor identified efficiently. Moreover, the complexity of mechatronic products is growing continuously due to an ongoing impact of software on product functions. In addition, the quality of a product is often judged by the quality of its functions. Thus it becomes hard to track the functions of a specific product and how they are realized and the quality of the product functions cannot be assured. Daimler is facing this problem by extending the traditional requirement list with functional requirements in the early design stages. This function oriented product description (FOPD) is leading to a mature product specification, because it is able to grow and adapt while designing the current mechatronic product and the following product generations of one product family. This work presents a novel approach to gain a benefit directly from the FOPD for the succeeding design process. Therefore the authors provide directions for deriving the so-called extended function structure (EFS) from a FOPD. The EFS is enhancing the traditional function structure by considering sensors, actors and the control logic explicitly. This approach will be exemplified in a case study.

This paper describes SANCHO, a mobile robot intended to perform within crowded areas as a servant, for instance as a fair or congress host. This robot has been constructed upon a commercial platform on which a number of sensors and devices have been integrated. A software control architecture has been implemented and adapted to this particular robot, enabling it to perform in human scenarios. Among the different subsystems of the control architecture developed for SANCHO, we highlight in this paper two of the most relevant ones: the navigation component which permits the robot to navigate in a safe and robust manner within crowded and dynamic environments, and the communication component which provides different possibilities for human-robot interaction. We illustrate the performance of SANCHO through a number of experiences carried out in public shows.

Maximal-length binary shift register sequences have been known for a long time. They have many interesting properties, one of them is that when taken in blocks of n consecutive positions they form 2 n - 1 different codes in a closed circular sequence. This property can be used for measuring absolute angular positions as the circle can be divided in as many parts as different codes can be retrieved. This paper describes how a closed binary sequence with arbitrary length can be effectively designed with the minimal possible block-length, using linear feedback shift registers (LFSR). Such sequences can be used for measuring a specified exact number of angular positions, using the minimal possible number of detectors allowed by linear methods.

This paper reports on the experience of the 2008 international summer school on mechatronics, jointly organized by the University of M'alaga (Spain) and the Technical University of Dresden (Germany). An important part of the hands-on practice and two student competitions have been based on the LEGO Mindstorms NXT Set. To stimulate lab work with representative general purpose software tools, LabVIEW and the NXT add-ons have been used. The paper proposes basic LabVIEW structures for several LEGO case study practices. A description of the course as well as an assessment on student competences are also included.

This paper deals with the localization and trajectory tracking control problems of tracked mobile robots under slip conditions. The proposed control law consists of the modification of a well-known control algorithm based on the feedback linearization technique, in which additional parameters have been included in order to compensate for the slip effects. Furthermore, an Indirect Kalman Filter has been used to improve the localization of the robot. Real tests show promising results.

In this paper, a new iterative learning algorithm is proposed for repetitive nonlinear systems. The control system employs a combination of state feedback and iterative learning control (ILC) in which the coefficients of states are learned similar to ILC methods. The control system is in a closed loop format both in iteration domain (because of ILC) and in time domain (because of feedback control) which improves the robustness of the conventional ILC. The convergence of the control algorithm is also proved. Finally, simulation results for a 5-DOF manipulator have been presented to illustrate that the proposed algorithm is more robust than a first order P type ILC method at the presence of white Gaussian noise as a nonrepeating disturbance.

This work presents a solution to solve Industrial Cranes kinematic control problem also called Automatic Travel Control (ATC) [10]. Aspects such as optimal trajectory reference calculation considering: process cycle time and distance travelled minimization, improvements in mechanical transmission systems useful life, prohibited areas and obstacles in the crane workspace, etc., and load position control with close tracking of trajectory reference avoiding excessive load swinging angles too, are analyzed and tackled applying Intelligent Control Techniques based on Genetic Algorithms and Neural Networks. The use of numerical and Hardware in the Loop (HiL) simulations, together with rapid prototyping advanced tools make quick changes and fast iterations between conceptual, preliminary, detailed, prototyping and validation design stages possible, allowing to reduce embedded control system development time and also increasing industrial crane overall quality.

In this paper, a robust-adaptive controller is developed for trajectory tracking of two rigid-link electrically-driven (RLED) robot manipulators carrying a rigid object. First, the dynamic model of the cooperative robots is derived. This model is written in a combined form such that the forces exerted by the object on the manipulators are not explicitly appeared in the dynamic model. A robust-adaptive controller is then applied to the cooperative robotic system in the voltage input level in order to asymptotically stabilize the tracking error. The robust-adaptive controller has the advantage that it does not require an exact knowledge of the dynamical equation of the system as well as its parameters. Furthermore, the controller does not need the measurement of the forces and moments at the contact points. Finally, simulation and experimental results are provided to illustrate the performance of the control algorithm.

This paper proposes an in-pipe robot adaptable to pipe diameter change. The robot can adapt to 400 to 700 mm diameter piping. A pantograph mechanism provides the adaptability and the robot drives using tracks. One track module consists of front and rear tracks connected by an active joint with structural compliance. Its passive foldable characteristics provide information of the frontal space and help keeping contact with the surface on which it travels. This paper also suggests two control algorithms. One is a method to keeping proper normal force without pressure sensors. The other is a posture control to move in curved pipe by pantograph angle detection. These algorithms are verified by experiment.

Tactile sensors are applied to different areas like robotics, medicine or virtual reality. Many of these sensors are based on piezoresistive films that cover an array of electrodes. This approach is simple and cheap and seems to be able to fit the requirements of applications like manipulation with robotic hands or grippers. Local preprocessing is a must in these systems to reduce errors and interferences and cope with the large amount of data from the sensor. This paper presents a circuitry based on a FPGA to implement the interface to the tactile sensor. The approach consists in a direct connection and can save area and get a more compact solution than other proposals that need more integrated circuits. Results from a first implementation based on a development board are shown to illustrate the feasibility of this strategy.

In this paper a new approach to detect skin in coloured images is proposed. The new method uses the classification of the three colour components of the RGB system (Red, Green and Blue), with a skin classifier. The proposed approach uses an adaptive methodology embedded in the skin classifier algorithm for pixel classification. The adaptive algorithm varies the image brightness in each one of the RGB colour components, in order to reduce the influence of different illumination environments (lighting conditions). Experimental results show the validity of the proposed methodology.

The non-destructive inspection of generator stators is a repetitive and cost-intensive task. For some types with very small entrance gaps (around 9 mm height), it was even necessary to always remove the rotor. This paper describes the design and prototype implementation of a new robotic crawler which is only 8 mm high and thus can inspect all types of generators with the rotor installed. Different solutions of how to realize torque transmission and attraction forces at such a small size are discussed, as well as the design of magnetic guiding wheels with a mechanism to fold them when passing the narrow entrance gap. The paper concludes with some test results - both in an artificial test environment and in real generators - and provides an outlook on future improvements of the prototype.

This article presents the mechanical design, hardware architecture and control scheme for critic joints in biped robots. A dynamic simulator was developed in order to quantify torque and currents motor requirements for different gait trajectories. The particular characteristics of biped robots has led to an important design effort in transmission systems, which is deeply discussed before presenting our choice. A specific electronic architecture has been proposed in order to provide the maximum accuracy in trajectory tracking for critic joints. Thus, an absolute encoder located at the output shaft will provide, through the CAN bus, the necessary information to properly correct the joint reference from the global stabilizer. A model-free approach and a Smith predictor on the loop are combined to deal with the transmission uncertainty and the network delays, respectively.

Since Jul. 2008, Beijing started a clean public transportation plan for the 29th Olympic Games. As a part of this plan, three fuel cell buses will work in a fixed bus line for one year as green energy vehicle demonstration for public. This is the first time to demonstrate homemade fuel cell buses in Beijing. The buses really serve as an ordinary bus on the streets of Beijing. Some control strategies are not adequately mature yet during the complex transient city cycle and are still needed to be optimized with the updating experiment data collected with day-to-day operation. Due to the speciality of fuel cell engine and electrified power-train system, some particular measurement, monitoring and calibration devices are ensuring normal operation of the fuel cell bus in the demonstration. The 3-axial accelerations of the fuel cell buses are the significant parameters to evaluate dynamical performance and manipulation stability. Furthermore they also feature the characteristic of city cycle route in demonstration. In order to measure and monitor the 3-axial accelerations of the fuel cell bus rapidly and conveniently, a novel wireless portable online monitoring system based on Java 2nd Micro Edition (J2ME) and Micro-Electro Mechanical Systems (MEMS) technology is implemented. The monitoring terminal could be a cell phone, PDA or any other smart mobile device with Bluetooth interface. The data exchange between monitoring terminals and VCU (Vehicle Control Unit) is highly secure under the guarantee of the Bluetooth pairing and authentication mechanism.

Ability to detect and to isolate faults which may affect the system depends essentially on instrumentation architecture. This is why, before designing an industrial supervision system, determination of monitoring ability based on technical specifications is important. Used methods in the consulted literature are based on a model given as a set of collected data in different modes (faulty and normal) or under complex differential equations. In the present paper it will be shown how the behavioral, structural and causal properties of the bond graph model can be used for monitoring ability analysis (which part of the system is over, just or under constrained) with no need of calculation. The developed method is applied to the designing a real time monitoring of an electromechanical system.

Object recognition techniques are well known in the field of machine vision, and aim at the classification of certain observed rigid objects based on the information acquired by a specific sensor. These techniques can either be performed in the 2D image space by simply applying suitable image processing algorithms, or in the real world 3D space by performing surface reconstruction of the object's surface and comparing it with a database of known CAD data. This paper presents a combination of techniques which not only recognize and categorize the observed rigid objects but also compute their 3D pose (position and orientation) with respect an industrial robot's workspace frame. This task is very useful in the field of robotics as it allows an industrial robot to simultaneously recognize and follow the displacements of a specific rigid object, among other objects that may co-exist in the same environment.

This paper describes the design strategy of an experimental platform which works as a test bed for teleoperation. It studies the performance of the executed tasks with different configurations and settings. The two key elements of a teleoperation interface are haptics and video perception. They inform the operator about the status of the remote or virtual environment. Specific hardware has been developed for both interactions as explained in the paper. These specific hardware components allow studying different control scheme for haptic devices and visual stereoscopic images on a computer screen. Results of the tests to this date are shown at the end and up-coming experiments are proposed.

This paper presents the development and implementation of a real time hybrid fuzzy-PID control paradigm for an aerodynamic test rig, a twin rotor multi-input-multi-output system (TRMS) which resembles the dynamics of a helicopter in certain aspects. The TRMS can be perceived as a challenging control problem due to its high nonlinearity, the coupling effects between its two axes and the inaccessibility of some of its states and outputs for measurements. The objective of the controller is to move the beam of the TRMS to the desired positions accurately addressing these demanding attributes. The controllers are based on the accurate dynamic models for both vertical and horizontal movements of the system. A fuzzy controller is firstly designed according to the characteristics of the process and then improved with an integrator, in order to reduce the steady state error compared to a conventional fuzzy controller. The responses of the controllers are validated using various reference inputs. A comparative performance study between the developed hybrid fuzzy-PID control approach and the single PID based approach is also made in this investigation.

In this paper, the stability of microstepping is investigated via Lyapunov method. A Lyapunov based control is proposed for the position tracking of a Permanent Magnet (PM) stepper motor. Given static inputs to the two phase PM stepper motor, it is proven that the convergence of equilibrium points is guaranteed by LaSalle's theorem. For position tracking, the relationships between the voltage input and current output of each phase for the position tracking are derived. From the relationships, the Lyapunov based controller is developed for the position tracking. Simulation results showed that the rotor angle and speed tracking performance of the proposed controller are good comparison to microstepping with current feedback PI controller.