System Design And Research On Vibtation Feedback Based Grasp Control Of Intelligent Prostheses

With the development of modern industry and transportation, there is a continued increase in the prevalence of people living with limb loss because of accidental injury and natural disasters. On the other hand, the majority of people with lower limb amputations have acquired their amputations as a result of disease processes such as diabetes mellitus. Intelligent prostheses can enhance the ability for grasping and manipulating objects so that the amputees can lead a better life and work better. Thus, it is of great significance to carry on research on how to restore amputees' limb function and to enable them better manipulation of delicate objects in daily life with the assist of intelligent prostheses. This dissertation conduct the research on the sensory feedback of the intelligent prostheses in the process of grasping and research on the vibration feedback based grasp control of the intelligent prostheses. By introducing users into the control loop of the prostheses, the control experience can be improved.In the research about the sensory feedback of the intelligent prostheses, we conduct experiments of grasping mass-variant object and grasping of objects with different shape and stiffness, and collect the outputs of the six tactile array sensors equipped on the SCHUNK Dexterous Hand during the experiment processes. In the data analysis part, the recorded sensor readouts were visualized using pseudo coloring technique to get an intuitive knowledge of the distribution of the pressure during experiments, and also the average force curves were analyzed in order to get more knowledge of force variation under different load conditions.In the research about the vibration feedback based grasp control of the intelligent prostheses, human was included in the control loop of the intelligent prostheses by providing vibration feedback according to the sensory information. First the experiment system was divided into three parts according to the function and were realized separately. Then the grasping experiments were conducted under two conditions, i.e. grasping with visual feedback only and grasping with visual feedback and vibration feedback. In the experiments, objects of different mass and stiffness were used for grasping tasks. Finally we analysed the effects of introducing vibration feedback in the grasp control of intelligent prostheses by comparing the grasp performances under these two experiment conditions.The research on sensory feedback in grasping movement revealed the force distribution and variation on the hand when objects of virable mass and objects with different shape and stiffness were grasped, which was of great significance to the realization of self-adaptive grasping and was also important for bringing out slippage-detection based force control algrithom for grasping objects with virable mass. The research on vibration based grasp control of the intelligent prostheses indicated that the participation of the users in the control loop by providing vibration feedback according to the sensory information on the prostheses can lead to a better performance, thus improve the user experience in amputees' daily life.