Design of a six degree-of-freedom haptic hybrid platform manipultor

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2010Includes bibliographical references (leaves: 97-103)Text in English; Abstract: Turkish and Englishxv, 115 leavesThe word Haptic, based on an ancient Greek word called haptios, means related with touch. As an area of robotics, haptics technology provides the sense of touch for robotic applications that involve interaction with human operator and the environment. The sense of touch accompanied with the visual feedback is enough to gather most of the information about a certain environment. It increases the precision of teleoperation and sensation levels of the virtual reality (VR) applications by exerting physical properties of the environment such as forces, motions, textures. Currently, haptic devices find use in many VR and teleoperation applications. The objective of this thesis is to design a novel Six Degree-of-Freedom (DOF) haptic desktop device with a new structure that has the potential to increase the precision in the haptics technology. First, previously developed haptic devices and manipulator structures are reviewed. Following this, the conceptual designs are formed and a hybrid structured haptic device is designed manufactured and tested. Developed haptic device.s control algorithm and VR application is developed in Matlab© Simulink. Integration of the mechanism with mechanical, electromechanical and electronic components and the initial tests of the system are executed and the results are presented. According to the results, performance of the developed device is discussed and future works are addressed

Controllable and reversible tuning of material rigidity for robot applications

Tunable rigidity materials have potentially widespread implications in robotic technologies. They enable morphological shape change while maintaining structural strength, and can reversibly alternate between rigid, load bearing and compliant, flexible states capable of deformation within unstructured environments. In this review, we cover a range of materials with mechanical rigidity that can be reversibly tuned using one of several stimuli (e.g. heat, electrical current, electric field, magnetism, etc.). We explain the mechanisms by which these materials change rigidity and how they have been used for robot tasks. We quantitatively assess the performance in terms of the magnitude of rigidity, variation ratio, response time, and energy consumption, and explore the correlations between these desired characteristics as principles for material design and usage

Use of McKibben muscle in a haptic interface

One of the most relevant issues in the development of a haptic interface is the choice of the actuators that are devoted to generating the reflection forces. This work has been particularly focused on the employment of the McKibben muscle to this aim. A prototype of one finger has been realized that is intended to be part of a haptic glove, and is based on an articulated mechanism driven by a McKibben muscle. A dynamic model of the finger has been created and validated; then, it has been used to define the control algorithm of the device. Experimental tests highlighted the static and dynamic effectiveness of the device and proved that a McKibben muscle can be appropriately used in such an application

Research progress of flexible sensor and its interaction technology in force feedback electronic clothing

The sense in simulated reality is the key of human-computer interaction technology. Force feedback interaction technology is an important factor to realize simulated force sense in virtual reality. It can truly reproduce the physical information such as the mass, inertia and hardness of things in the virtual world. This paper summarizes the flexible sensors commonly used in force feedback technology and the development and research status of virtual reality wearable electronic clothing equipment based on force feedback technology, summarizes the principles of several force feedback structures, analyzes and compares their characteristics and main application fields. This paper briefly describes the prospect of force feedback technology, summarizes the trend of high-precision, multi-modal and multi-point interaction of force feedback equipment in the future, and puts forward some suggestions on miniaturization, softness and authenticity of force feedback technology in combination with the application characteristics of wearable electronic clothing

Rehabilitation Engineering

Population ageing has major consequences and implications in all areas of our daily life as well as other important aspects, such as economic growth, savings, investment and consumption, labour markets, pensions, property and care from one generation to another. Additionally, health and related care, family composition and life-style, housing and migration are also affected. Given the rapid increase in the aging of the population and the further increase that is expected in the coming years, an important problem that has to be faced is the corresponding increase in chronic illness, disabilities, and loss of functional independence endemic to the elderly (WHO 2008). For this reason, novel methods of rehabilitation and care management are urgently needed. This book covers many rehabilitation support systems and robots developed for upper limbs, lower limbs as well as visually impaired condition. Other than upper limbs, the lower limb research works are also discussed like motorized foot rest for electric powered wheelchair and standing assistance device

Development of Finger ContracturePrevention System For Early Post StrokeRehabilitation

芝浦尾工業大学2016年

Elbow exoskeleton mechanism for multistage poststroke rehabilitation.

More than three million people are suffering from stroke in England. The process of post-stroke rehabilitation consists of a series of biomechanical exercises- controlled joint movement in acute phase; external assistance in the mid phase; and variable levels of resistance in the last phase. Post-stroke rehabilitation performed by physiotherapist has many limitations including cost, time, repeatability and intensity of exercises. Although a large variety of arm exoskeletons have been developed in the last two decades to substitute the conventional exercises provided by physiotherapist, most of these systems have limitations with structural configuration, sensory data acquisition and control architecture. It is still difficult to facilitate multistage post-stroke rehabilitation to patients sited around hospital bed without expert intervention. To support this, a framework for elbow exoskeleton has been developed that is portable and has the potential to offer all three types of exercises (external force, assistive and resistive) in a single structure. The design enhances torque to weight ratio compared to joint based actuation systems. The structural lengths of the exoskeleton are determined based on the mean anthropometric parameters of healthy users and the lengths of upperarm and forearm are determined to fit a wide range of users. The operation of the exoskeleton is divided into three regions where each type of exercise can be served in a specific way depending on the requirements of users. Electric motor provides power in the first region of operation whereas spring based assistive force is used in the second region and spring based resistive force is applied in the third region. This design concept provides an engineering solution of integrating three phases of post-stroke exercises in a single device. With this strategy, the energy source is only used in the first region to power the motor whereas the other two modes of exercise can work on the stored energy of springs. All these operations are controlled by a single motor and the maximum torque of the motor required is only 5 Nm. However, due to mechanical advantage, the exoskeleton can provide the joint torque up to 10 Nm. To remove the dependency on biosensor, the exoskeleton has been designed with a hardware-based mechanism that can provide assistive and resistive force. All exoskeleton components are integrated into a microcontroller-based circuit for measuring three joint parameters (angle, velocity and torque) and for controlling exercises. A user-friendly, multi-purpose graphical interface has been developed for participants to control the mode of exercise and it can be managed manually or in automatic mode. To validate the conceptual design, a prototype of the exoskeleton has been developed and it has been tested with healthy subjects. The generated assistive torque can be varied up to 0.037 Nm whereas resistive torque can be varied up to 0.057 Nm. The mass of the exoskeleton is approximately 1.8 kg. Two comparative studies have been performed to assess the measurement accuracy of the exoskeleton. In the first study, data collected from two healthy participants after using the exoskeleton and Kinect sensor by keeping Kinect sensor as reference. The mean measurement errors in joint angle are within 5.18 % for participant 1 and 1.66% for participant 2; the errors in torque measurement are within 8.48% and 7.93% respectively. In the next study, the repeatability of joint measurement by exoskeleton is analysed. The exoskeleton has been used by three healthy users in two rotation cycles. It shows a strong correction (correlation coefficient: 0.99) between two consecutive joint angle measurements and standard deviation is calculated to determine the error margin which comes under acceptable range (maximum: 8.897). The research embodied in this thesis presents a design framework of a portable exoskeleton model for providing three modes of exercises, which could provide a potential solution for all stages of post- stroke rehabilitation

Wearable Systems for the Hand with High Functionality and Usability for Virtual Reality

Department of Mechanical EngineeringAs an advanced physical human-robot interaction (pHRI), there has been a surge of interest in a haptic device for virtual reality (VR) field. Especially, wearable force feedback devices which can measure the human???s motion and apply the feeling of the object have been actively investigated. It is ideal to measure all motions of the user, and apply the feelings to all body parts, but it requires many sensors and actuators, resulting that bulky and heavy system. Therefore, the wearable system, which focuses on some body parts which are essential for interacting with virtual environments, should be developed by considering the number of sensors and actuators practically. When it comes to the body parts, the hand is important to grasp and manipulate the object, and interact with external environments. In terms of realizing the feeling of the object, the kinesthetic (force feedback) information mainly affect to distinguish the geometry of the object and manipulate the object, rather than tactile information such as pressure, shear, temperature, etc. Consequently, the wearable force feedback systems for the hand have been actively investigated. For realizing the feeling of the object, various stiffness should be generated by the force feedback system. Since the stiffness is the force change along the position change, two main functions of finger motion measurement and force feedback are required. Those functions can be summarized as functionality. Other subjective factors can be summarized as usability. The usability is the ease of use and usefulness, including quantifiable characteristics, such as user task performances, subjective satisfaction, learnability and user; in this study, it was interpreted as design, wearability, ease of use, etc. However, there are few wearable systems for the hand to utilize the applications for virtual reality. The main reason is that the hand has relatively many degrees of freedom (DOFs) and range of motion (ROM), and generate large force compared to its small size; the wearable systems which could measure the finger motion accurately and apply the precise force were large and heavy because many actuators and sensors were required. In other words, the wearable systems that satisfied high functionality were poor in usability. For high usability, many devices by small motors have been developed, but the corresponding functionality were deteriorated. Designing the system that satisfies both functionality and usability seems to be a trade-off problem, but the wearable system for virtual reality can be applied to the real world only when both elements are satisfied. Therefore, the main goal of this dissertation is to develop a system of both high functionality and usability in order to apply to the actual virtual reality field. Especially, this study aims to enhance the usability by proposing new methods for wearability, ease of use, and by using a small motor to reduce the system weight, but maintain the functionality through various mechanical approaches such as cable and linkage driven mechanisms. First, finger motion measurement systems have been investigated because accurate measurement of the finger motion itself has been challenged due to its many degrees of freedom (DOFs) and range of motion (ROM) based on complex anatomical structures. A compact and glove-type system with potentiometers, springs and flexible wires was proposed to calculate the finger joint angle by length change of the cable. For high functionality and usability, the system which could measure three-dimensional finger motion for users of various hand sizes without a calibration process was developed. Second, the wearable force feedback systems, which achieve both finger motion measurement and force control, were developed. A dual-cable system was proposed to combine force feedback structures on the aforementioned finger motion measurement system with cables. A linkage mechanism based wearable system, called as WeHAPTIC (Wearable Haptic Interface of Accurate Position Tracking and Interactive force Control), were developed to overcome the limitations of the previous system. It was designed to directly connect fingertips and the system to allow various users, to easily worn by latchet based one click structure and to calibrate system with only one simple posture. Lastly, WeHAPTIC-Light was exploited to reduce the system weight by changing to small motors. The cable and linkage driven mechanisms were combined to measure the finger motion without any calibration process and permit fast finger motion. Lastly, extensive experiments were performed for performance verification of our system as the haptic device. Not only physical assessment of the system, but also psychophysical evaluation, which is a quantitative evaluation related to human perception ability, were conducted in this dissertation for comprehensive performance evaluation as the haptic interface.clos

Development of a 4-DoF Active Upper Limb Orthosis

In this paper, the designs and manufacturing process of a powered upper limb orthosis are presented. The orthosis is an exoskeleton worn on one arm by the user and fixed to the trunk. The orthosis’ architecture, design, and manufacturing process are presented and discussed. Estimations of the ranges of movement related to daily living activities are presented. The preliminary tests to verify the functionality of the design show encouraging results