We have been developing exoskeleton robots for assisting the motion of physically weak individuals such as elderly or slightly disabled in daily life. In this paper we propose an EMG-based control of a three degree of freedom (3-DOF) exoskeleton robot for the forearm pronation/supination motion, wrist flexion/extension motion and ulnar/radial deviation. The paper describes the hardware design of the exoskeleton robot and the control method. The skin surface electromyographic (EMG) signals of muscles in forearm of the exoskeleton’s user and the hand force/forearm torque are used as input information for the proposed controller. By applying the skin surface EMG signals as main input signals to the controller, automatic control of the robot can be realized without manipulating any other equipment. Fuzzy control method has been applied to realize the natural and flexible motion assist. An experiment has been performed to evaluate the proposed exoskeleton robot.

Категория: Ищем научные статьи | Нет комментариев »

Force feedback from the virtual world can greatly enhance the sense of immersion even for simple applications. The ISU force reflecting exoskeleton enables the user to interact dynamically with simulated environments by providing an electro-magnetic haptic interface between the human and the environment. This paper describes the force and trajectory control interface for the PUMA 560 manipulator that supports the ISU force reflecting exoskeleton hand tracking system. The combined exoskeleton-PUMA system allows the application of virtual forces to the digits of the human finger. Two different typical synthetic environments are programmed and tested using the ISU force reflecting exoskeleton haptic interface device. The experimental results shows that the magnetic interface gives adequate force levels for perception of virtual objects, enhancing the feeling of immersion in the virtual environment, and that the PUMA 560 provides adequate tracking and free motion capabilities for the ISUexoskeleton system

Категория: Ищем научные статьи | Нет комментариев »

A human wearing an exoskeleton-type assistive device results in a parallel control system that includes two controllers: anexoskeleton controller and a human brain that includes the spinal cord and the cerebrum. Unknown and complicated characteristics of the brain dynamically interact with the exoskeleton controller, which makes the controller design challenging. In this paper, the motion control system of a human is regarded as a feedback control loop that consists of the brain, muscles, and the dynamics of the extended human body. The brain is modeled as a control algorithm amplified by a fictitious gain (FG). The FG is adjusted to compensate for characteristic changes in the muscle and human body dynamics due to physical impairment, varying load, or any other causes. In this paper, an exoskeleton controller that realizes the FG is designed, and its performance and robustness are discussed.

Категория: Ищем научные статьи | Нет комментариев »

As a stage toward a complete upper-arm motion assisted exoskeleton robot (i.e., 7DOF) this paper focused on the development of a 2DOF exoskeleton robot to rehabilitate and to ease wrist joint movements. To perform essential daily activities the movement of shoulder, elbow, and wrist play a vital role and proper functioning of the upper-limb is essential. We therefore have been developing an exoskeleton robot (ExoRob) to rehabilitate and to ease upper limb motion. The proposed 2DOF ExoRob is designed to be worn on the lateral side of the forearm in order to provide naturalistic movements (i.e., flexion/extension and radial/ulnar deviation) of the wrist joint. This paper also focuses on the modeling and control of the proposed ExoRob. A kinematic model of ExoRob has been developed based on modified Denavit-Hartenberg notations. In dynamic simulations of the proposed ExoRob, a nonlinear sliding mode control technique is employed, where trajectory tracking that corresponds to typical rehab (passive) exercises has been carried out to evaluate the performances of the developed model and controller. Moreover experiments were carried out with PID controller to further evaluate the developed model regard to trajectory tracking. Simulated and experimental results show that the controller is able to maneuver the ExoRob efficiently to track the desired trajectories, which in this case consisted in passive arm movements. Such movements are typically used in rehabilitation and could be performed very efficiently with the developed ExoRob and the controller.

Категория: Ищем научные статьи | Нет комментариев »