A Novel Design and Implementation of a 4-DOF Upper Limb Exoskeleton for Stroke Rehabilitation with Active Assistive Control Strategy

We developed a robot, CUREs (Chulalongkorn University Rehabilitation Robotic Exoskeleton system), for upper extremity rehabilitation. The active assistive control strategy based on the impedance force control is developed and implemented to obtain assistive-resistive paths tracking for rehabilitation activities. The desired trajectory or rehabilitated training pattern for each specific patient need to be assigned first by a medical doctor and a physical therapy. The therapist can program the desired trajectory by guiding the patient arm based on the assigned path pattern and the set of via points will be stored and used for generating the desired trajectory. The desired trajectory will be stored specific for the patient and can be called back anytime. During the rehabilitation, the robot can assist and resist the patient’s arm to follow the desired trajectory. If the patient has difficulty moving his arm to track the desired path, the robot will help by adding more torque to help the patient to move his arm to reduce the error between the desired path and the actual posture. And if the patient himself can move his arm tracking the desired path, the robot will not apply any more force to assist or resist. The necessary state variables such as angular position and torque can be recorded during the training. The main purpose of the experiment, follow the medical ethic, is to assure that there is no side effect for using this rehabilitation robot. Five subacute stroke patients participated in this pilot study. All patients have severe upper extremity weakness. The medical doctor will assign the training pattern based on patient condition. The result showed that the Fugl-Meyer Assessment Upper Extremity Scale was improved after 10 days of training in all participants without any sign of side effect.We developed a robot, CUREs (Chulalongkorn University Rehabilitation Robotic Exoskeleton system), for upper extremity rehabilitation. The active assistive control strategy based on the impedance force control is developed and implemented to obtain assistive-resistive paths tracking for rehabilitation activities. The desired trajectory or rehabilitated training pattern for each specific patient need to be assigned first by a medical doctor and a physical therapy. The therapist can program the desired trajectory by guiding the patient arm based on the assigned path pattern and the set of via points will be stored and used for generating the desired trajectory. The desired trajectory will be stored specific for the patient and can be called back anytime. During the rehabilitation, the robot can assist and resist the patient’s arm to follow the desired trajectory. If the patient has difficulty moving his arm to track the desired path, the robot will help by adding more torque to help the patient to move his arm to reduce the error between the desired path and the actual posture. And if the patient himself can move his arm tracking the desired path, the robot will not apply any more force to assist or resist. The necessary state variables such as angular position and torque can be recorded during the training. The main purpose of the experiment, follow the medical ethic, is to assure that there is no side effect for using this rehabilitation robot. Five subacute stroke patients participated in this pilot study. All patients have severe upper extremity weakness. The medical doctor will assign the training pattern based on patient condition. The result showed that the Fugl-Meyer Assessment Upper Extremity Scale was improved after 10 days of training in all participants without any sign of side effect

Mechanical Power to Identify Human Performance for a Lower Limb Rehabilitation Robot

Rehabilitation robots usually provide trainings with a certain training modality and activity. The patient’s performance measure such as mechanical power is also derived for those specific trainings. This article aims to demonstrate the implementation of our lower limb rehabilitation robot in sitting position for providing the training with games and to propose the derivation of the human mechanical power as a performance measure. The control algorithm for active exercise and the integration of the related software and hardware are also developed to offer proper environment for a game session. The derivation of the mechanical power of a human subject in the training is verified with active and passive cycling exercises. Three healthy subjects participate in the game sessions provided by the robot. It is found that the game sessions can provide the movement training with sufficient intensity. Moreover, the mechanical power obtained from the proposed method is able to identify the intensity of training tasks, human performance, and human attention in the training

A 3D End-Effector Robot for Upper Limb Functional Rehabilitation of Hemiparesis Patients

Robot-assisted therapy is a new type of rehabilitation that allows for highly repetitive, intensive, adaptable, and quantifiable physical training. It is increasingly being used to restore motor function, particularly in stroke survivors with upper limb paresis. The end-effector type robot allows natural movements without complex structure which is ideal for functional rehabilitation training. A 3D end-effector base on a five-bar linkage has been proposed to improve the common end-effector type that covers mechanical design, dynamic control strategy, and application of rehabilitation training or exercise. The dynamic controllers are deweighting with gravity compensation, passive mobilization or active assistive, and the virtual spring-damper wall concept. These controllers are used for developing functional rehabilitation training or exercise from an engineering point of view based on experiences in developing various types of rehabilitation robots. The experiments, based on the performance of the controllers, have been conducted with healthy subjects. The experimental results have shown very promising results and can be extended to various types of functional rehabilitation

The optimal control and design of a flexible manipulator arm

Ph.D.Wayne J. Boo

A Lower Limb Rehabilitation Robot in Sitting Position with a Review of Training Activities

Robots for stroke rehabilitation at the lower limbs in sitting/lying position have been developed extensively. Some of them have been applied in clinics and shown the potential of the recovery of poststroke patients who suffer from hemiparesis. These robots were developed to provide training at different joints of lower limbs with various activities and modalities. This article reviews the training activities that were realized by rehabilitation robots in literature, in order to offer insights for developing a novel robot suitable for stroke rehabilitation. The control system of the lower limb rehabilitation robot in sitting position that was introduced in the previous work is discussed in detail to demonstrate the behavior of the robot while training a subject. The nonlinear impedance control law, based on active assistive control strategy, is able to define the response of the robot with more specifications while the passivity property and the robustness of the system is verified. A preliminary experiment is conducted on a healthy subject to show that the robot is able to perform active assistive exercises with various training activities and assist the subject to complete the training with desired level of assistance

Design studies on a robotic device for ultrasonic inspection

To be presented at Fourth CISM-IFToMM Symposium on Theory and Practice of Robots and Manipulators, Warsaw, Poland, September 8-12, 1981.Design studies in progress on a special purpose robot are described. The robot is to be used for ultrasonic inspection of extruded and forged parts immersed in water in a large tank. The studies focus on establishing the best tradeoff between light weigh, with the associated fast movement time for large motion, and rigidity – as characterized by high structural natural frequency. High natural frequency allows high servo bandwidth and consequently faster response to small disturbances and greater dynamic accuracy