A Novel 3D Printed Wrist Rehabilitation Robot: Design, Development and Optimal Trajectory Planning

Rehabilitation of patients suffering after stroke impairment is a lengthy process and requires experienced therapists. These limitations have led to the introduction of rehabilitation robots that can operate for a longer time while eliminating the lack of professional therapists. In this thesis, we propose a two-degrees-of-freedom robot for wrist rehabilitation, referred to as MOCH. The MOCH mechanism comprises a remote center of motion (RCM) mechanism with a rotation center outside of the robot structure. When the patient holds the robot end-effector, coinciding the RCM of the robot with the rotation axis of the wrist, allows pure rotational motion of the hand. As the RCM lies out of the robot structure, there is less risk of interference with the patient. Furthermore, MOCH benefits a novel actuation that enables the actuators to be grounded, reducing the inertia and the size of the robot. The optimal design of MOCH is provided considering the mechanical criteria and requirements of the wrist rehabilitation. Based on the proposed design, a prototype of the robot is developed with a total mass of 1.3 kg using 3D printing technology. Additionally, we introduce a novel methodology for passive rehabilitation exercise, exploiting the wrist dynamics which removes the complexity of force/impedance control approaches. This method involves designing an optimal trajectory within the limits of the wrist motion, and to keep the applied torque on the patient's hand in a safe range without using force sensors. The proposed trajectory is tested on a healthy individual using the implemented prototype

Ground Robotic Hand Applications for the Space Program study (GRASP)

This document reports on a NASA-STDP effort to address research interests of the NASA Kennedy Space Center (KSC) through a study entitled, Ground Robotic-Hand Applications for the Space Program (GRASP). The primary objective of the GRASP study was to identify beneficial applications of specialized end-effectors and robotic hand devices for automating any ground operations which are performed at the Kennedy Space Center. Thus, operations for expendable vehicles, the Space Shuttle and its components, and all payloads were included in the study. Typical benefits of automating operations, or augmenting human operators performing physical tasks, include: reduced costs; enhanced safety and reliability; and reduced processing turnaround time

Design and Validation of a Variable Stiffness Three Degree of Freedom Planar Robot Arm

The need exists for robotic manipulators that can interact with an environment having uncertain kinematic constraints. A robot has been designed and built for proof of concept of a passive variable compliance control strategy that can vary joint stiffness to achieve higher performance dexterous manipulation. This novel planar robot incorporating variable stiffness actuators and common industrial controls allows the robot to comply with its environment when needed but also have high stiffness for precise motion control in free space. To perform both functions well, a high stiffness ratio (max/min stiffness) is required. A stiffness ratio up to 492 was achieved. The robot performance was evaluated with the task of turning a crank to lift a weight despite nominal positioning inaccuracy. The novel variable stiffness robot was able to complete the task faster and with lower constraint forces than a traditional force-controlled stiff robot. The time to complete the task using passive variable stiffness control was twenty-nine times faster with constraint forces less than one fifth those achieved using traditional active compliance control

Development of an upper-body robotic rehabilitation platform that furthers motor recovery after neuromuscular injuries

This dissertation presents the development of an upper-body exoskeleton and its control framework for robotic rehabilitation of the arm and shoulder after a neurological disorder such as a stroke. The first step is designing an exoskeleton hardware that supports natural mobility of the human upper body with a wide range of motion for enabling most rehabilitation exercises. The exoskeleton is equipped with torque-controllable actuation units for implementing various robotic rehabilitation protocols based on force and impedance behaviors. The control framework is designed to exhibit a highly backdrivable behavior with a gravity compensation for the robot's weight and optional gravity support for user's arm weight to promote voluntary movements of patients with motor impairments. The control framework also serves as a `substrate' of other robotic control behaviors for rehabilitation exercises by superimposing desired force or impedance profiles. A stability analysis is performed to examine the coupled stability between the robot and human. After designing the hardware and control, several experiments are carried out to test the mobility and dynamic behavior of the robot. Lastly, a human subject study evaluates the effectiveness of the robot's shoulder mechanism and control algorithm in assisting the coordination around the shoulder. The results show that the robot induces desirable coordination in the presence of abnormalities at the shoulder.Mechanical Engineerin

Analysis of 4-dof force/torque sensor for intelligent gripper

This paper describes the development of a six-axis gripper force sensor that measure forces f_x,f_y and f_zand M_x,M_y and M_z simultaneously, and the intelligent gripper will be using the six-axis sensor for grasping or holding any object with the force calculated. To grasp any object of unknown dimensions and weight by using an intelligent gripper safely the forces are to be calculated along the gripping direction and gravitational direction, and perform the force control with the measured forces. Thus, the intelligent gripper should be composed of six-axis gripper force sensor that measure forces f_x,f_y and f_z and M_x,M_y and M_zat the same time. In this paper, a six-axis gripper force sensor for measuring forces f_x,f_y and f_zand M_x,M_y and M_z simultaneously were newly modeled using 16 strain gauges. The structure of a six-axis wrist force/moment sensor was modeled for an intelligent hand in robot newly. And the sensing elements of it were designed by using FEM design system ANSYS. All along the way the stress points are found out where max. And min. stresses are applicable and the design of sensor is done so

Design of Novel Sensors and Instruments for Minimally Invasive Lung Tumour Localization via Palpation

Minimally Invasive Thoracoscopic Surgery (MITS) has become the treatment of choice for lung cancer. However, MITS prevents the surgeons from using manual palpation, thereby often making it challenging to reliably locate the tumours for resection. This thesis presents the design, analysis and validation of novel tactile sensors, a novel miniature force sensor, a robotic instrument, and a wireless hand-held instrument to address this limitation. The low-cost, disposable tactile sensors have been shown to easily detect a 5 mm tumour located 10 mm deep in soft tissue. The force sensor can measure six degrees of freedom forces and torques with temperature compensation using a single optical fiber. The robotic instrument is compatible with the da Vinci surgical robot and allows the use of tactile sensing, force sensing and ultrasound to localize the tumours. The wireless hand-held instrument allows the use of tactile sensing in procedures where a robot is not available

Glove Exoskeleton for Extra-Vehicular Activities: Analysis of Requirements and Prototype Design

The objective of the thesis is the development of a prototype of a lightweight hand exoskeleton designed to be embedded in the gloved hand of an astronaut and to overcome the stiffness of the pressurized space suit. The system should be able to provide force and precision to the hand grip. The project involves various elements, in particular the analysis of the characteristics of the hand and of the EVA glove. Moreover solutions related to sensor and actuator should be investigated. Finally the study and the design of an appropriate robotic structure able to fullfit the requirements have to be performed

Physical Diagnosis and Rehabilitation Technologies

The book focuses on the diagnosis, evaluation, and assistance of gait disorders; all the papers have been contributed by research groups related to assistive robotics, instrumentations, and augmentative devices

MRI-VisAct: a Bowden cable-driven MRI compatible series viscoelastic actuator

Presence of the strong magnetic fields in the Magnetic Resonance Imaging (MRI) environment limits the integration of robotic rehabilitation systems to the MRI process. The tendency to improve imaging quality by the amplification of magnetic field strength further tightens the bidirectional compatibility constraints on MRI compatible rehabilitation devices. We present the design, control, and characterization of MRI-VisAct—a low-cost, Bowden cable-actuated rotary series viscoelastic actuator that fulfills the bidirectional compatibility requirements to the maximum extend. Components of MRI-VisAct that are placed in the magnet room are built using nonconductive, diamagnetic MRI compatible materials, while ferromagnetic/paramagnetic components are placed in the control room, located outside the MRI room. Power and data transmission are achieved through Bowden-cables and fiber optics, respectively. This arrangement ensures that neuroimaging artifacts are minimized, while safety hazards are eliminated, and the device performance is not affected by the magnetic field. MRIVisAct works under closed-loop torque control enabled through series viscoelastic actuation. MRI-VisAct is fully customizable; it can serve as the building block of higher degrees of freedom MRI compatible robotic devices