Soft Sensor Based On Dielectric Elastomer: Optimization And Application In The Human Upper Limbs Motion Measurement

In recent years,the demands of human motion capture have been increasing in the fields of exoskeleton robots,human-computer interaction,sports and rehabilitation research,and many other areas.Some technologies for human motion capture are already applied in engineering,but they suffer from serious limitations in adaptation,comfort and accuracy,and so on.Dielectric elastomer sensors(DESs)are soft and lightweight,can be worn directly on the human body,and also can overcome the above disadvantages.So,the sensor was used to measure the motion of wrist,elbow and shoulder based on the performance optimization of the existing senor in laboratory in this paper.The following work had been done in this paper.The phenomenon of capacitance relaxation discovered by experiments was studied.The phenomenon means that the capacitance of the DE will decrease with time if the deformation is invariable.It has a severe influence on the accuracy of DESs.So,the impact factors and some possible reason of capacitance relaxation were studied by related experiments in this paper.And the method was given to reduce the accuracy falling caused by capacitance relaxation.Some methods had been proposed to solve the problem of the existing sensor in laboratory.Including: fabricating the dielectric elastomer membrane in the clean room to avoid the defection;bonding the protection layer and the electrode with oxygenplasma treatment to ensure the uniform thickness of protection layer;proposing a digital filtering method to filter the 50 Hz electromagnetic noise.Some design proposal had been proposed to guide the design of DESs because various sensors were needed to measure joint motion accurately.And these criterions were validated by experiments.Then,the performance parameters of the sensor were tested,such as linearity,hysteresis and sensitivity,and so on.In upper limbs motion measurement in this paper,some sensors had been designed according to the characteristic of every joint motion for wrist,elbow and shoulder.Then,these sensors were worn on body to measure joint motion.To improve measurement accuracy,decoupling method was given for wrist motion and shoulder motion.