In this paper we present a method to calibrate the surface EMG signal-to-force-relationship online. For this, a simple biomechanical model composed of bones and muscles is used. The calibration is based on an online optimization algorithm where the error between the movement of the human and the movement computed with the biomechanical model is minimized. The proposed method is part of a control system for an exoskeleton robot that should aid the wearer in everyday-life situations like walking, standing up and sitting down. In contrast to existing methods for the calculation of the EMG signal-to-force-relationship, we are not interested in the exact force values of every single muscle, but our model groups some muscles together and uses the EMG signal of one of those muscles as a representative for the group to simplify calculations. The performance of the presented method was investigated on the leg movement in sagittal plane without contact to the environment.

(далее…)

Категория: Научные статьи | Нет комментариев »

In this paper, a mouse-shaped haptic device is proposed. The device solves conventional problems of previously developed devices such as structure and control complexity and operating difficulties. We adopted multiple finger inputs in order to carry out complicated tasks and in order to highly adapt to the environment. To develop the multi-fingered haptic device, we focused on anatomical knowledge and neurophysiology. Since there is a primacy of the visual information over somatic sensation, we believe the movable range of human fingers does not necessarily have to be completely satisfied, i.e. visual information can compensate for the difference between the displacement of the haptic device and that of the slave device in a master-slave system. We applied this feature to miniaturize and simplify the device. To confirm the usefulness of our developed device for a virtual reality system, we carried out three experiments: position control, familiarization and force feedback. The results show the effectiveness of the developed haptic device.

(далее…)

Категория: Научные статьи | Нет комментариев »

Exoskeletons for human performance augmentation are controlled and wearable devices or machines that can increase the speed, strength, and endurance of the operator. So far most researchers focus on the upper limb exoskeletons. To help those who need to travel long distances by feet with heavy loads such as infantry soldiers, this paper presents a control principle of a lower extremity exoskeleton. An exoskeleton foot is designed to measure the human and the exoskeleton’s ZMP. Using the measured human ZMP as the reference together with the human leg position signals, the exoskeleton’s ZMP is modified by trunk compensation. Test prototypes and initial experiment results are also demonstrated.

(далее…)

Категория: Научные статьи | Нет комментариев »