Development of Active Support Splint driven by Pneumatic Soft Actuator (ASSIST)

In this study, in order to realize an assist of independent life for the elderly or people in need of care and relieve a physical burden for care worker, an active support splint driven by pneumatic soft actuator (ASSIST) has been developed. ASSIST consists of a plastic interface with the palm and arm and two rotary-type soft actuators put in both sides of appliance. In this paper, the fundamental characteristics of ASSIST is described, and then the effectiveness of this splint is experimentally discussed. Finally, the operation of ASSIST based on a human intention is described. </p

Advancing the Functionality and Wearability of Robotic Hand Orthoses Towards Activities of Daily Living in Stroke Patients

Post stroke rehabilitation is effective when a large number of motor repetitions are provided to patients. However, conventional physical therapy or traditional desktop-size robot aided rehabilitation do not provide sufficient number of repetitions due to cost and logistical barriers. Our vision is to realize a wearable and functional hand orthosis that could be used outside of controlled, clinical settings, thus allowing for more training repetitions. Furthermore, if such a device can prove effective for Activities of Daily Living (ADLs) while actively worn, this can incentivize patients to increase its use, further enhancing rehabilitative effects. However, in order to provide such clinical benefits, the device must be completely wearable without obtrusive features, and intuitive to control even for non-experts. In this thesis, we thus focus on wearability, functionality, and intuitive intent detection technology for a novel hand robot, and assess its performance when used both as a rehabilitative device and an assistive tool. A fully wearable device must deliver meaningful manipulation capability in small and lightweight package. In this context, we investigate the capability of single-actuator devices to assist whole hand movement patterns through a network of exotendons. Our prototypes combine a single linear actuator (mounted on a forearm splint) with a network of exotendons (routed on the surface of a soft glove). We investigate two possible tendon network configurations: one that produces full finger extension (overcoming flexor spasticity) and one that combines proximal flexion with distal extension at each finger. In experiments with stroke survivors, we measure the force levels needed to overcome various levels of spasticity and to open the hand for grasping using the first of these configurations, and qualitatively demonstrate the ability to execute fingertip grasps using the second. Our results support the feasibility of developing future wearable devices able to assist a range of manipulation tasks. In order to further improve the wearability of the device, we propose two designs that provide effective force transmission by increasing moment arms around finger joints. We evaluate the designs with geometric models and experiment using a 3D-printed artificial finger to find force and joint angle characteristics of the suggested structures. We also perform clinical tests with stroke patients to demonstrate the feasibility of the designs. The testing supports the hypothesis that the proposed designs efficiently elicit extension of the digits in patients with spasticity as compared to existing baselines. With the suggested transmission designs, the device can deliver sufficient extension force even when the users have increased muscle tone due to fatigue. The vision of an orthotic device used for ADLs can only be realized if the patients are able to operate the device themselves. However, the field is generally lacking effective methods by which the user can operate the device: such controls must be effective, intuitive, and robust to the wide range of possible impairment patterns. The variety of encountered upper limb impairment patterns in stroke patients means that a single sensing modality, such as electromyography, might not be sufficient to enable controls for a broad range of users. To address this significant gap, we introduce a multimodal sensing and interaction paradigm for an active hand orthosis. In our proof-of-concept implementation, EMG is complemented by other sensing modalities, such as finger bend and contact pressure sensors. We propose multimodal interaction methods that utilize this sensory data as input, and show they can enable tasks for stroke survivors who exhibit different impairment patterns. We then assess the performance of the robotic orthosis for two possible roles: as a therapeutic tool that facilitates device mediated hand exercises to recover neuromuscular function, or as an assistive device for use in everyday activities to aid functional use of the hand. 11 chronic stroke (> 2 years) patients with moderate muscle tone (Modified Ashworth Scale ≤ 2 in upper extremity) engage in a month-long training protocol using the orthosis. Individuals are evaluated using standardized outcome measures, both with and without orthosis assistance. The results highlight the potential for wearable and user-driven robotic hand orthoses to extend the use and training of the affected upper limb after stroke. The advances proposed in this thesis have the potential to enable robotic based hand rehabilitation during daily activities (as opposed to isolated hand exercises with limited upper limb engagement) and over extended periods of time, even in a patient’s home environment. Numerous challenges must still be overcome in order to achieve this vision, related to design (compact devices with easier donning/doffing), control (robust yet intuitive intent inferral), and effectiveness (improved functionality in a wider range of metrics). However, if these challenges can be addressed, wearable robotic devices have the potential to greatly extend the use and training of the affected upper limb after stroke, and help improve the quality of life for a large patient population

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

Wearable exoskeleton systems based-on pneumatic soft actuators and controlled by parallel processing

Human assistance innovation is essential in an increasingly aging society and one technology that may be applicable is exoskeletons. However, traditional rigid exoskeletons have many drawbacks. This research includes the design and implementation of upper-limb power assist and rehabilitation exoskeletons based on pneumatic soft actuators. A novel extensor-contractor pneumatic muscle has been designed and constructed. This new actuator has bidirectional action, allowing it to both extend and contract, as well as create force in both directions. A mathematical model has been developed for the new novel actuator which depicts the output force of the actuator. Another new design has been used to create a novel bending pneumatic muscle, based on an extending McKibben muscle and modelled mathematically according to its geometric parameters. This novel bending muscle design has been used to create two versions of power augmentation gloves. These exoskeletons are controlled by adaptive controllers using human intention. For finger rehabilitation a glove has been developed to bend the fingers (full bending) by using our novel bending muscles. Inspired by the zero position (straight fingers) problem for post-stroke patients, a new controllable stiffness bending actuator has been developed with a novel prototype. To control this new rehabilitation exoskeleton, online and offline controller systems have been designed for the hand exoskeleton and the results have been assessed experimentally. Another new design of variable stiffness actuator, which controls the bending segment, has been developed to create a new version of hand exoskeletons in order to achieve more rehabilitation movements in the same single glove. For Forearm rehabilitation, a rehabilitation exoskeleton has been developed for pronation and supination movements by using the novel extensor-contractor pneumatic muscle. For the Elbow rehabilitation an elbow rehabilitation exoskeleton was designed which relies on novel two-directional bending actuators with online and offline feedback controllers. Lastly for upper-limb joint is the wrist, we designed a novel all-directional bending actuator by using the moulding bladder to develop the wrist rehabilitation exoskeleton by a single all-directional bending muscle. Finally, a totally portable, power assistive and rehabilitative prototype has been developed using a parallel processing intelligent control chip

Soft Pneumatic Actuator Fascicles for High Force and Reliability

Soft pneumatic actuators (SPAs) are found in mobile robots, assistive wearable devices, and rehabilitative technologies. While soft actuators have been one of the most crucial elements of technology leading the development of the soft robotics field, they fall short of force output and bandwidth requirements for many tasks. Additionally, other general problems remain open including robustness, controllability, and repeatability. The SPA-pack architecture presented here aims to satisfy these standards of reliability crucial to the field of soft robotics, while also improving the basic performance capabilities of SPAs by borrowing advantages leveraged ubiquitously in biology; namely the structured parallel arrangement of lower power actuators to form the basis of a larger, more powerful actuator module. An SPA-pack module consisting of a number of smaller SPAs will be studied using an analytical model and physical prototype. Experimental measurements show an SPA-pack to generate over 112 N linear force, while the model indicates the benefit of parallel actuator grouping over a geometrically equivalent single SPA scales as an increasing function of the number of individual actuators in the group. For a module of four actuators, a 23 % increase in force production over a volumetrically equivalent single SPA is predicted and validated, while further gains appear possible up to 50 %. These findings affirm the advantage of utilizing a fascicle structure for high-performance soft robotic applications over existing monolithic SPA designs. An example high-performance soft robotic platform will be presented to demonstrate the capability of SPA-pack modules in a complete and functional system

Design of an active orthotic device for joint management.

Existing treatment programs and procedures are incapable of addressing the complications encountered with patients who experience spasticity and hypertonia related joint contractures. Current passive therapy procedures and devices are only capable of managing the extent of joint contractures on patients with chronic and acute onset severe neurological disorders. The project was conceived as a means to develop an active device that is capable of adapting to the state of the joint to mange the extent of contractures and to permit consideration for the prevalence of spastic activity episodes and hypertonia. The project focused on the design of the physical prototype and the controller software in order to regulate the operation of such a device. Additionally, the signal conditioning and sensor package was developed as determined to be appropriate for the requirements of the device. The operation of the device was verified in the bench-top environment in the laboratory and on human subjects in order to qualify, verify, and tune the position tracking capability of the device, spastic activity detection and rejection capability of the device, and the operation of patient controlled devices. The overall operation of the device was evaluated on a group of human subjects. Using simulated contractures and spastic activity episodes, the validity of the preliminary deterministic test data was confirmed as was the appropriate operation of the device. The end prototype devices are capable of responding to a spastic activity episode by maintaining a constant load in addition to mimicking the passive extension behavior of conventional commercial devices

A hand exoskeleton for study of rehabilitation and assistance of spinal cord injury patients

A large number of people experience neurological disorders in their life time, and these patients seek to regain their body functions with rehabilitation and assistive devices. In this dissertation, we present the development of a hand exoskeleton, called Maestro, which is designed to advance research in fields of hand rehabilitation and hand assistive devices. Maestro is mechanically and electrically robust, accurate in sensing and actuation, and compatible to various rehabilitation schemes, subjects, hardware/software, and different operators. As a result of these features, Maestro has led to research on adaptive control theories for diverse properties of hands, the development of a hand-wrist exoskeleton, the development of a novel rehabilitation framework, progress of hand muscle fatigues, and assistance for SCI patients. Particularly on the assistance for SCI patients, we present that the advantage of a compliant hand assistive device may result in high success ratios for grasping various objects required in activities of daily living (ADL) with surface EMG sensors. The hand functions of SCI subjects are evaluated with and without Maestro through a standardized hand function test called Sollerman hand function test (SHFT). The results with six SCI subjects show that the hand functions of C6 and C7 SCI subjects improved with assistance from Maestro.Mechanical Engineerin

Modelling and EMG based Control of Upper Limb Exoskeletons for Hand Impairments

Functional losses associated with hand impairments have led to the growing development of hand exoskeletons. The main challenges are to develop the exoskeletons that work according to the user’s motion intention, which can be done by utilizing the electromyogram signals generated by forearm muscles contributed from the movement and/or grasping abilities of the hand. In this research, modelling and EMG based control of hand exoskeletons with the aim to assist stroke survivors in regaining their hand strength and functionality, and improve their quality of life is presented