Investigations On A Soft Strain Sensor Used On Measurement Of Lower Limbs Motion

In recent years,with the aging of the population,exoskeleton robots have been wide used in assisted rehabilitation,assisted walking and physical development.At present,sensors developed for traditional robots have some problems,such as poor wearability,poor biocompatibility and poor adaptability.In order to achieve the motion assistance of multidegree-of-freedom and multi-motion state more effectively and ensure the flexibility,realtime and reliability of the interaction between the wearer and the skeleton,a flexible sensor system is needed to monitor the wearer's motion.It provides intelligent sensing technology support for adaptive exoskeleton control in complex environment.Therefore,a set of soft sensors which can be applied to lower limb motion measurement in complex land and water environments is developed in this paper.The main work of this paper includes:Firstly,this paper designs and manufactures the sensor according to its application scenario and corresponding technical requirements,including theoretical model building,sensor body structure design,circuit design,material selection and process design.Then,the performances of the sensor are measured by land and underwater experiments to meet the requirements of the complex environment and a number of performance requirements;through the measurement of the performance of the sensor,technical indicators are provided for the application of the sensor.The measured performance includes the static performance(linearity,return error),service life,stability and the ability to resist water disturbance(water flow,water pressure)in the water environment.Finally,a human lower limb motion measurement system is developed based on soft sensors,and experiments of human lower limb motion measurement on land and underwater are carried out.Through the analysis of the experimental results,the measurement effect of the sensor system is evaluated,including the measurement accuracy of sagittal angle of the lower limb joints on land and the discrimination of the motion mode of the lower limb of the underwater human body.