Exoskeletons are attracting a great attention as a new means of rehabilitation devices. In such applications, control algorithms of exoskeletons are often inspired by nature for natural and effective assistance for patients. In this paper, a control algorithm is inspired by aquatic therapy. Aquatic therapy has various benefits for rehabilitation processes based on useful properties of water, e.g. buoyancy and drag. However, realization of such effects is challenged by limitations in hardware, such as mechanical impedance or impreciseness of actuator forces. Therefore, the resistive forces generated by actuators, which cause serious discomfort to patients, are precisely modeled and compensated to realize the control algorithm inspired by aquatic therapy effectively. The proposed methods are implemented in SUBAR developed by Sogang University and verified by experiments.

Категория: Ищем научные статьи | Нет комментариев »

In this paper, we propose a power assist device for lower back flexion and extension, when carrying a heavy load. To see the effect of the device, we model a human body and analyze a compression force in his lower back, as well as the evaluation of a supported force at a hand position. A prototype of the device is manufactured and a controller of the device is developed, which can follow a voluntary human motion assisting his strength.

Категория: Ищем научные статьи | Нет комментариев »

For robot teleoperation, a lot of research has been done to control the slave robot from a remote site using a masterarm. The concept of a distributed controller architecture for the masterarm is introduced in the paper. To reduce possible non-uniform time delay and to have higher position command update rate, the host controller with distributed satellite controllers is developed. Each satellite controller measures the corresponding joint angle, while the host controller performs initial calibration, inverse kinematics calculation, and position commands generation. The host controller and the satellite controllers are networked via a SPI (serial peripheral interface) protocol. For force feedback, the host controller solves the joint torque relations based on the kinematics of the masterarm and the satellite controller controls each joint’s torque. This distributed controller greatly reduces calculation and control loads and makes the electrical wiring very simple. In order to measure finger movement of the operator, the master hand is developed using infrared light. A similar slave satellite controller for this master hand is interfaced to the host controller via a SPI network. For teleoperation of the KIST humanoid robot which has two arms and two hands, the masterarm controller with one host controller and 16 satellite controllers is implemented. Force feedback with less than 2 msec update rate is achieved. This masterarm/hand is also integrated with a graphic model instead of using the slave robot. The experimental results show the performance of the distributed controller

Категория: Ищем научные статьи | Нет комментариев »

The feasibility of an alternative method to support body weight in a powered exoskeleton is demonstrated. Instead of using an overhead suspension system, body weight is supported by augmenting the joint moments through virtual model control. The advantages of this novel method is that it allows for independent support of the left and right leg, and does not interfere with the excitation of cutanous afferents and balance of the body or trunk. Results show that after a short familiarization period the activity of muscles during initial stance reduces and kinematics become close to normal.

Категория: Ищем научные статьи | Нет комментариев »

Chronic hand impairment is common following stroke. This paper presents an actuated thumb exoskeleton (ATX) to facilitate research in hand rehabilitation therapy. The ATX presented in this work permits independent bi-directional actuation in each of the 5 degrees-of-freedom (DOF) of the thumb using a mechanism that has 5 active DOF and 3 passive DOF. The ATX is able to provide considerable joint torques for the user while still allowing backdrivability through flexible shaft transmission. A prototype has been built and experiments were conducted to evaluate the closed-loop position control. Further improvement and future work are discussed.

Категория: Ищем научные статьи | Нет комментариев »