2) Lower Body Exoskeleton-based Compliant Bipedal Walking Support for Paraplegia:
In this research, the main purpose is to enable individuals who suffer impaired lower body functionality, to regain walking ability with the support of a wearable robotic system. Our emphasis is the utilization of active compliance and software-controlled passivity in a way to relieve the upper body support that is needed to maintain dynamic balance. That way, individuals may experience somewhat more ergonomic and comfortable walking locomotion. The same property also enables them to step over unexpected terrain irregularities.
Despite impressive exoskeleton systems, not much of them investigated paraplegia walking on uneven surfaces. Therefore, in this study, we would like to make a step towards that direction, even though our system is not completely ready for clinical experimentation. We conducted several experiments on various able-bodied human subjects. The results seem promising; our proposed controller (Virtual Admittance Controller) has potentials to be utilized for compliant walking support for paraplegia patients.
Related Publications: A journal paper is under preparation.
[IC23] Barkan Ugurlu, Hironori Oshima, and Tatsuo Narikiyo, Lower Body Exoskeleton-Supported Compliant Bipedal Walking for Paraplegics: How to Reduce Upper Body Effort?, in Proc. of the IEEE International Conference on Robotics and Automation (ICRA), Hong Kong, 2014, pp. 1354-1360. [pdf]
1) Robotic Rehabilitation and Power Augmentation Using a Wearable Upper Body Exoskeleton:
In order to promote robotic rehabilitation and power augmentation, a wearable exoskeleton is constructed with 3 objectives in mind: Versatility, cost-efficiency and competency&safety. The whole system is actuated via electrical actuators with harmonic gears. It includes no sensors except encoders.
To this end, I exploited off-the-shelf joint-level compensation techniques developed for robot manipulators to achieve torque/force-sensorless control while handling exoskeleton-based robotic rehabilitation and power augmentation tasks. In evaluating the performance of the exoskeleton, I conducted 3 types of experiments: i) Power Augmentation to manipulate objects with unknown mass. ii) Patient-active Rehabilitation task in which the human-wearer moves his arm against the robot arm with real-time adjustable impedance (muscle-strenghtening exercise). iii) Patient-passive Rehabilitation task in which the exoskeleton moves the human-wearer's arm to prevent myolysis without being influenced on the human parameters.
Its lower body is used to enable exoskeleton-based walking support for paraplegia patients. This study is still an ongoing process.
Related Publications: [J7] Barkan Ugurlu, Masayoshi Nishimura, Kazuyuki Hyodo, Michihiro Kawanishi, and Tatsuo Narikiyo, Proof of Concept for Robot-aided Upper Limb Rehabilitation Using Disturbance Observers, IEEE Transactions on Human-Machine Systems, Accepted, in print. (SCI) [pdf]
Remarks: This project is carried out in Toyota Technological Institute (TTI), Nagoya, Japan. The system is constructed before I join to TTI as a post-doc fellow. I designated necessary control algorithms and carried out experiments. Working on this system forced me to come up with the idea of testing to what extent state-of-the-art compensation techniques are useful for a torque-sensorless force control strategies only based on the estimation of external torques.