Band: Abstracts der Vorträge des 6. Workshops der Automed 2006 Editors: T. Ellerbrock

In September 2006 an integrated European project was launched entitled "Flexible Assembly Systems through Workplace-Sharing and Time-Sharing Human-Machine Cooperation (PISA) ". PISA belongs to the research area "next generation of flexible assembly technology and processes ". The general aim of the project is to develop intelligent assist systems (IAS) in order to support the human worker instead of replace him. Thus, flexibility should not be reached through fully automated assembly systems but should instead support the better integration of human workers.

BACKGROUND:Gait restoration is an integral part of rehabilitation of brain lesioned patients. Modern concepts favour a task-specific repetitive approach, i.e. who wants to regain walking has to walk, while tone-inhibiting and gait preparatory manoeuvres had dominated therapy before. Following the first mobilization out of the bed, the wheelchair-bound patient should have the possibility to practise complex gait cycles as soon as possible. Steps in this direction were treadmill training with partial body weight support and most recently gait machines enabling the repetitive training of even surface gait and even of stair climbing.RESULTS:With treadmill training harness-secured and partially relieved wheelchair-mobilised patients could practise up to 1000 steps per session for the first time. Controlled trials in stroke and SCI patients, however, failed to show a superior result when compared to walking exercise on the floor. Most likely explanation was the effort for the therapists, e.g. manually setting the paretic limbs during the swing phase resulting in a too little gait intensity. The next steps were gait machines, either consisting of a powered exoskeleton and a treadmill (Lokomat, AutoAmbulator) or an electromechanical solution with the harness secured patient placed on movable foot plates (Gait Trainer GT I). For the latter, a large multi-centre trial with 155 non-ambulatory stroke patients (DEGAS) revealed a superior gait ability and competence in basic activities of living in the experimental group. The HapticWalker continued the end effector concept of movable foot plates, now fully programmable and equipped with 6 DOF force sensors. This device for the first time enables training of arbitrary walking situations, hence not only the simulation of floor walking but also for example of stair climbing and perturbations.CONCLUSION:Locomotor therapy is a fascinating new tool in rehabilitation, which is in line with modern principles of motor relearning promoting a task-specific repetitive approach. Sophisticated technical developments and positive randomized controlled trials form the basis of a growing acceptance worldwide to the benefits or our patients.

The paper presents a novel concept of lightweight and inherently safe robotic systems for assisting the locomotion recovery therapy and training. This concept, referred to as STRING-MAN, is established on string-puppet idea and utilizes modular wire robot components and advanced artificial muscles drives. An overview of the system's fundamental components, such as mechanical structure, patient-machine interface, sensory systems, control algorithms, etc., is given in the paper. The results of initial experiments clearly demonstrate the benefits and potential of new concept. Finally further development of STRING-MAN idea towards practical and inherently safe robotic rehabilitation assistants has also been presented.

PISA is a European Integrated Project (IP) in the research area “next generation of flexible assembly technology and processes”. The general aim of the project is to develop intelligent assist systems (IAS) in order to support the human worker instead of replacing him. Thus, flexibility should not be reached through fully automated assembly systems but should instead support the better integration of human workers. This paper gives a report on the project, launched in September 2006.

The growing number of product variants, smaller lot sizes, reduced time to market and shorter lifecycles of products have lead to increasing demands on automation equipment and concepts. As a solution, hybrid human integrated approaches are proposed. The idea is to combine human flexibility, intelligence and skills with the advantages of sophisticated technical systems. Intelligent assist systems (IAS) represent a novel class of assembly systems capable of working with human operators in two modes: workplace sharing and time sharing. This paper presents a novel collaborative robot system (“Cobot”) capable of sharing the workspace with the human co-worker and collaborating with him through direct physical contact.

This paper presents a new haptic locomotion interface, which comprises two programmable foot platforms with permanent foot machine contact. It is designed as a scalable and modular system with unit-by-unit extensibility offering up to six plus one degrees of freedom (DOF) per foot. The basic setup comprises three DOF per foot in the sagittal plane.The machine is based on a rigid hybrid parallel-serial robot kinematics structure. It is equipped with electrical direct drive motors, enabling highly dynamic footplate motions. For contact force measurement, six DOF force/torque sensors are mounted under each foot platform. The system was developed for major application in gait rehabilitation, hence great importance was attached to the incorporation of maximum passive and active security measures for machine users and medical operating personnel.The simulator is able to perform walking trajectories with speeds of up to 5 km/h and 120 steps/min. The system is able to simulate not only slow and “smooth” trajectories like walking on an even floor, up/down staircases, but also foot motions like walking on rough ground or even stumbling or sliding, which require high system dynamics.The machine is controlled by a self-developed full-featured robot control whose soft and hardware is based on up-to-date industrial standards and interfaces. The robot control software is based on RTLinux and runs on an industrial PC. The real-time motion generator includes a newly developed Fourier-based algorithm for the interpolation of natural cyclic walking trajectories. For the implementation of asynchronous events (e.g., sliding, stumbling), the controller comprises especially developed algorithms for automatic motion override adaptation. Different modes of haptic behavior needed for gait rehabilitation, ranging from full foot support during swing phase to completely passive behavior, are currently under development.Intuitive and safe machine operation by nontechnical personnel such as clinicians and physiotherapists is achieved via a separate Windows-based graphical user interface software comprising different window areas for machine programming and operation, real-time off-line simulation and online data visualization in two and three dimensions has been developed as well.A working prototype of the system has been built and tested successfully, including all soft and hardware components. Although the machine has been designed and built for major application in gait rehabilitation, its range of applicability is not limited to this area. It could be integrated into any setup requiring a highly dynamic haptic foot interface and permanent foot machine contact if needed.

This paper presents several novel interactive human-robot systems which were recently developed at IPK. These systems were designed for direct physical interaction between humans and robots. The principal structures and functions of the following robotic systems are briefly presented: ROBOPED, an advanced parallel robot for orthopedic diagnostics and rehabilitation, STRING-MAN, a wire robot for gait rehabilitation, and IPK's Kobot, a collaborative manipulator for advanced material handling and assembly.

Computer based models have become an indispensable means for the planning, optimisation and operation of industrial manufacturing systems. The usability and significance of the models strongly depends on their accuracy, availability and functional extent. Today, suitable models for components of automation systems are available only for some types of components. Functionality for simulation purposes is often limited and integration costs are often still considerable. These problems were widely solved for industrial robots in the 'Realistic Robot Simulation' (RRS) projects. There, world-wide standards for Virtual Robot Controllers (VRCs) were created. Now, this success should be transferred to other components of automation systems like programmable logic controllers (PLCs), human-machine interface (HMI) systems, bus systems and effector sensor systems.

For the development of biped robot and artificial limb as well as for the rehabilitation of patients whose legs are injured or have difficulty in movement, a gait phase online identification and calculation of centre of pressure (CoP) system is researched. In previous researches, the force sensitive resistors were fit inside of the shoes, which were called sole sensors. However according to our own experiments, this is not effective method for the identification of the gait phase because there is a relative movement between the foot and shoe if the shoes aren't adequately adapted to the feet. In our research the force sensors are installed on exsole instead of on the insole, which cause the readings to accurately correspond with the physical information of human. 4 pieces of force sensitive resistors, one piece of position sensor and a fibre sensor that is for the measuring of the bend of the legs are used. The 5 normal gait phases such as stance, stance-kneebend, heel-off, swing-bend, swing-extend heel-strike and 4 irregularities such as stance-external-tip over, stance-internal-tip over, forward tipping over, etc. can be identified with a combination's of sensors. CoP can be also calculated in real-time. The identification is independent from the order of the walking. The reliability of the results is 100% attainable. The first gait phase is also identifiable. Additionally, whether human walks fast or quite slowly doesn't influence to the identification result. The system self-calibration is carried out at the beginning of running. It is therefore ensured that the system measurement is 100% identical in relation to the walking of people.

The control system for a robotic walking simulator and rehabilitation device requires enhanced operation modes and control capabilities, compared to conventional industrial robot controllers. In order to be able to implement custom made algorithms at all levels of the controller and to have an extensible and reusable control environment, we decided to develop a full-featured robot control soft and hardware, including a graphical user interface (GUI), as a modular and open system. This paper describes the newly developed robot and simulator controller, including the graphical user interface, especially those features which distinguish it from conventional robot controllers.

This paper presents a novel robotic prototype for advanced gait rehabilitation. This system integrates sophisticated robotic technology with control algorithms. The robot opens up new possibilities for the field of rehabilitation for restoring posture balancing and gait motoric functions. The paper provides an overview of the system's fundamental components, such as mechanical structure, patient-machine interface, sensory systems, control algorithms, etc. The results of some initial experiments also are included.

A new kind of CVT(Continuously Variable Transmission) and COBOT (Collaborative robot) based on differential mechanism is introduced. There are two kinds of COBOT models: the serial and parallel. The principle of COBOT is analyzed and the dynamic model of COBOT is established. Taking the five-bar COBOT as a prototype,the dynamics of serial and parallel COBOT model is developed.

A novel 6-degree of freedom (6DOF) movement measuring system for biomechanical engineering was developed. The 6DOF measuring system is constructed from 3 pieces of 2-dimensional PSD (position sensing detector) and its corresponding light sources, laser-diode. The light sources are modulated laser-diode, which shines directly into the PSD So that the system is not sensitive to environmental factor e.g. magnet, ferromagnetic material, daylight etc. The measuring system was built in the laboratory. This measuring system is to be used in the rehabilitation system.

This paper presents a novel Cobotic system with differential CVT. The new system is significantly cheaper, simpler to control and more efficient than Cobots with S-CVTs. Both path-guidance and power-assist functions can be simply realized with the new system. Basic structures, kinematic and dynamic models, as well as control algorithms, which are essential for design, control synthesis and control of the system, are briefly presented in the paper.

Operating and path planning for mobile robots requires the knowledge of the position and orientation in the workspace. In unknown environments, the robot has to build a map and simultaneously localize itself in this map. This is referred to as “Simultaneous Localization and Map Building” (SLAM). In this paper, an approach to a SLAM method with a 2D laser scanner is described, focusing on robustness for low structured environments, limiting computational complexity for large areas and handling dynamic environments.

A novel 6-degree of freedom (6DOF) movement measuring system for biomechanical engineering was developed. The 6DOF measuring system is constructed from 3 pieces of 2-dimensional PSD (position sensing detector) and its corresponding light sources, laser-diode. The light sources are modulated laser-diode, which shines directly into the PSD So that the system is not sensitive to environmental factor e.g. magnet, ferromagnetic material, daylight etc. The measuring system was built in the laboratory. This measuring system is to be used in the rehabilitation system.

The restoration of walking capability is a key goal for patients after suffering from a stroke, traumatic brain injury or spinal cord injury. The paper describes a robotic device which enables the therapist to let the machine move the patients feet on programmable foot trajectories. On this device the patients feet are permanently fixed on two footplates. Force sensors are mounted on the footplates with compliance control algorithms for online adaptation of the foot trajectories to the patients walking capabilities. Furthermore, the kinematic and kinetic design parameters of the robotic system enable the machine to be used as a universal walking simulator, not just for rehabilitation purposes. In the haptic mode, the machine behaves as a haptic foot device for a variety of virtual ground conditions. Due to the high dynamic range needed to guide real walking trajectories, conventional industrial robots are not suitable for this task. Hence the authors developed a special robot system with high dynamics. This paper describes the development aspects of the design process of the new walking simulator.

Accurate simulation provides a significant means for cost reduction during planning and operation of manufacturing installations. Within the projects Realistic Robot Simulation the standards Robot Controller Simulation (RCS) Interface and Virtual Robot Controller (VRC) Interface were defined by international consortia of leading car makers, robot and simulator manufacturers and line builders, with Fraunhofer IPK, Berlin as project manager. For enabling accurate simulation of complete manufacturing lines, a new project entitled Virtual Programmable Logic Controller (VPLC) is planned. The article outlines the resulting potential of cost reduction throughout the life-time of an installation and gives an overview on the application of the standards for cost reduction.