Abstract. There exists uncertainties and environmental disturbances, such as mechanism friction and filling water into cups, etc., when a prosthetic hand grasps an object. Those disturbance can not be obtained easily because of the lack of sensors. Thus, a disturbance observe-based fuzzy control is presented for prosthetic hands. The environmental disturbance can be observed by using the proposed disturbance observer. The performance of the observer is analyzed. A fuzzy logical controller is then adopted to track the desired force. Finally, the proposed method is applied to controlling a single-freedom prosthetic hand. The experimental results show that the proposed method is effective.

In order to improve amputees quality of life, electromyogram (EMG) prosthetic hands have been developed to compensate for some daily activities. A force estimation method for prosthetic hands using surface electromyotraphy is proposed in the paper to help amputees. One hand of the subject is tied to imitate amputees. The subjects would grip the force sensor with his healthy hand, while doing the same thing with the tied hand. Meanwhile, EMG signals and force are acquired by LABVIEW. Then a muscle-force model based on stepwise regression method is established .The experiments are carried out to evaluate the grasping force on a single degree of freedom prosthetic hand. The experimental results show that the proposed method is effective.

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Abstract. Despite the rapid developments of prosthetic hands technologies in recent years, there still exists a huge gap between prosthetic hands and human hands in flexibility. The limitation of sensors attached to the prosthetic hand is one of the causes, and another reason is that the materials, weight, and stiffness of the object gripped by a prosthetic hand are unknown. Additionally, the external disturbances in prosthetic hands are not certain. The factors mentioned above lead to difficulties in controlling grasping force of prosthetic hands, and that affects the quality of prosthetic hands applications. Therefore, it is important to design a stable and reliable system to control grasping force. This paper presents a dual-loop control system of grasping force for prosthetic hands, and we carried out some relative experiments based on a single degrees of freedom prosthetic hand. The experiment results show that the proposed control system is effective.