Robotics 2010

Without a doubt, robotics has made an incredible progress over the last decades. The vision of developing, designing and creating technical systems that help humans to achieve hard and complex tasks, has intelligently led to an incredible variety of solutions. There are barely technical fields that could exhibit more interdisciplinary interconnections like robotics. This fact is generated by highly complex challenges imposed by robotic systems, especially the requirement on intelligent and autonomous operation. This book tries to give an insight into the evolutionary process that takes place in robotics. It provides articles covering a wide range of this exciting area. The progress of technical challenges and concepts may illuminate the relationship between developments that seem to be completely different at first sight. The robotics remains an exciting scientific and engineering field. The community looks optimistically ahead and also looks forward for the future challenges and new development

Robotic Functional Gait Rehabilitation with Tethered Pelvic Assist Device

The primary goal of human locomotion is to stably translate the center of mass (CoM) over the ground with minimum expenditure of energy. Pelvic movement is crucial for walking because the human CoM is located close to the pelvic center. Because of this anatomical feature, pelvic motion directly contributes to the metabolic expenditure, as well as in the balance to keep the center of mass between the legs. An abnormal pelvic motion during the gait not only causes overexertion, but also adversely affects the motion of the trunk and lower limbs. In order to study different interventions, recently a cable-actuated robotic system called Tethered Pelvic Assist Device (TPAD) was developed at ROAR laboratory at Columbia University. The cable-actuated system has a distinct advantage of applying three dimensional forces on the pelvis at discrete points in the gait cycle in contrast to rigid exoskeletons that restrict natural pelvic motion and add extra inertia from the rigid linkages. However, in order to effectively use TPAD for rehabilitation purposes, we still need to have a better understanding of how human gait is affected by different forces applied by TPAD on the pelvis. In the present dissertation, three different control methodologies for TPAD are discussed by performing human experiments with healthy subjects and patients with gait deficits. Moreover, the corresponding changes in the biomechanics during TPAD training are studied to understand how TPAD mechanistically influences the quality of the human gait. In Chapter 2, an ‘assist-as-needed’ controller is implemented to guide and correct the pelvic motion in three dimensions. Here, TPAD applies the correction force based on the deviation of the current position of the pelvic center from a pre-defined target trajectory. This force acts on the pelvic center to guide it towards the target trajectory. A subject in the device experiences a force field, where the magnitude becomes larger when the subject deviates further away from the target trajectory. This control strategy is tested by performing the experiments on healthy subjects with different target pelvic trajectories. Chapter 3 describes a robotic resistive training study using a continuous force on the pelvis to strengthen the weak limbs so that subjects can improve their walking. This study is designed to improve the abnormal gait of children with Cerebral Palsy (CP) who have a crouch gait. Crouch gait is caused by a combination of weak extensor muscles that do not produce adequate muscle forces to keep the posture upright, coupled with contraction of muscles that limit the joint range of motion. Among the extensor muscles, the soleus muscle acts as the major weight-bearing muscle to prevent the knees from collapsing forward during the middle of the stance phase when the foot is on the ground. Electromyography, kinematics, and clinical measurements of the patients with crouch gait show significant improvements in the gait quality after the resistive TPAD training performed over five weeks. Both Chapters 2 & 3 present interventions that are bilaterally applied on both legs. Chapter 4 introduces a training strategy that can be used for patients who have impairments in only one leg which results in manifests as asymmetric weight-bearing while walking. This training method is designed to improve the asymmetric weight bearing of the hemiparetic patients who overly rely on the stronger leg. The feasibility of this training method is tested by experiments with healthy subjects, where the controller creates an asymmetric force field to bring asymmetry in weight bearing during walking. In summary, the present dissertation is devoted to developing new training methods that utilize TPAD for rehabilitation purposes and characterize the responses of different force interventions by investigating the resulting biomechanics. We believe that these methodologies with TPAD can be used to improve abnormal gait patterns that are often observed in cerebral palsy or stroke patients

Joint Trajectory Generation and High-level Control for Patient-tailored Robotic Gait Rehabilitation

This dissertation presents a group of novel methods for robot-based gait rehabilitation which were developed aiming to offer more individualized therapies based on the specific condition of each patient, as well as to improve the overall rehabilitation experience for both patient and therapist. A novel methodology for gait pattern generation is proposed, which offers estimated hip and knee joint trajectories corresponding to healthy walking, and allows the therapist to graphically adapt the reference trajectories in order to fit better the patient's needs and disabilities. Additionally, the motion controllers for the hip and knee joints, mobile platform, and pelvic mechanism of an over-ground gait rehabilitation robotic system are also presented, as well as some proposed methods for assist as needed therapy. Two robot-patient synchronization approaches are also included in this work, together with a novel algorithm for online hip trajectory adaptation developed to reduce obstructive forces applied to the patient during therapy with compliant robotic systems. Finally, a prototype graphical user interface for the therapist is also presented

Sistema robótico ambulatorio de rehabilitación de marcha. Solución integrada de inducción de movimientos y descarga parcial de peso del paciente

En esta tesis doctoral se presenta el diseño, el desarrollo y la validación de un dispositivo robótico para el entrenamiento y la rehabilitación de la marcha de personas con deficiencia motora. Se basa en la combinación de un exoesqueleto bilateral activo de miembros inferiores y de una plataforma de descarga parcial de peso, regulable, que proporciona una alta estabilidad y seguridad durante la marcha. Se ha diseñado para proporcionar una marcha natural en un entorno real con una descarga adaptable, con el objeto de potenciar las capacidades motoras residuales del paciente, así como evitar o disminuir importantes problemas que aparecen por períodos largos de sedestación. Inicialmente, se presenta la caracterización de la marcha humana a través de sus parámetros espacio-temporales y cinemáticos, así como los sistemas empleados para su caracterización. Se hace igualmente una revisión del estado del arte de los sistemas tecnológicos de ayuda a la movilidad, proponiendo una clasificación en función de las capacidades motoras del usuario. Se realiza un especial énfasis en los dispositivos vestibles y en los entrenadores de marcha tanto en fase de investigación como comerciales. A partir de este estudio, se detectan las carencias que se marcan como objetivos a cumplir para el entrenador HYBRID, desarrollo central del trabajo realizado en esta tesis doctoral, dentro del proyecto nacional DPI 2011-28160-C03. Se detalla el diseño mecánico realizado, así como la integración hardware e implementación software de los subsistemas y su integración conjunta para su correcto funcionamiento de manera integrada. El sistema se diseña como una plataforma abierta que permite el procesamiento y el registro de señales para la caracterización de la marcha. El sistema ha sido validado con personas sanas como paso previo a la validación clínica. Esta se ha centrado en asegurar la estabilidad y seguridad del dispositivo, caracterizar la marcha desarrollada, comprobar la correcta inducción del movimiento sobre las extremidades inferiores del usuario, caracterizar las fuerzas de suspensión y determinar el grado de acoplamiento entre el sistema y el usuario. Finalmente, se ha validado el sistema con pacientes con lesión medular de distinto grado de afección y capacidades de locomoción. Se ha valorado el impacto metabólico en términos respiratorios, cardíacos y energéticos; además de los parámetros de la marcha desarrollada y las fuerzas de suspensión. Los resultados obtenidos tanto de las escalas objetivas empleadas como de las valoraciones subjetivas de los pacientes se han considerado satisfactorios en un buen grado y se presentan en la memoria, constatando el potencial del dispositivo como herramienta fiable para el entrenamiento de la marcha de personas con un alto grado de discapacidad motora.In this PhD thesis, the design, development and validation of a robotic device for the training and rehabilitation of people with motor deficits is presented. This robotic device is based on the combination of a powered bilateral lower limb exoskeleton and an adjustable partial body weight support platform, that gives high stability and safety during walking. It has been designed to provide natural gait in real environments with an adaptive support, focused on enhancing the residual motor abilities of the patient as well as avoiding or diminishing the numerous and important problems that appear after long periods of sitting. Initially, human gait characterization is presented through its spatio-temporal and kinematic parameters as well as the systems used for it. A review of the state-of-theart of the mobility devices is presented, proposing a classification based on the user's residual motor abilities. Special emphasis is placed on wearable devices and gait trainers in both the research field and the market. From this study, the identified shortcomings are proposed as the objectives to be achieved for the HYBRID gait trainer, framework of development of this PhD Thesis, within the national project DPI 2011-28160-C03. In this sense, the mechanical design, hardware integration, software implementation and integration of the subsystems is presented. The system is designed as an open platform that allows the integration of new functionalities, as well as the processing and recording of sensor signals for the gait characterization. The system has been validated with healthy people as a first step to the clinical validation with people with motor disabilities, people with spinal cord injury in this case. This first validation has been focused on ensuring the stability and safety of the device, the analysis of the gait developed with the HYBRID system, the validation of the induced movement of the lower limb in the user, the characterization of the unloading forces and the assessment of the degree of coupling between the system and the user. Finally, the system has been validated with spinal cord injured patients with different levels of motor disability. The metabolic impact in respiratory, cardiac and energetic terms has been evaluated; in addition to the characterization of the gait parameters and the unloading forces. The results obtained from the clinical scales and user experience evaluation, presented in this PhD thesis, have been considered satisfactory, confirming the potential of the device as a reliable tool for gait training of people with a high degree of motor disability.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Ángel Manuel Gil Agudo.- Secretario: María Dolores Blanco Rojas.- Vocal: Cristina Sánchez López de Pabl