Research On Signal Acquisition And Processing System Of Piezoresistive Polymer-based Flexible Sensor

One of the biggest features of the flexible sensor is that it can be synchronized with the elastic object to be measured,so that real-time detection of the force change of the measured object can be realized.It can be widely used in power electronics,sports equipment,aerospace,environmental monitoring,Human skin,wearable equipment,rail transit and many other fields.Flexible conductive materials made based on polymer micro-nano manufacturing technology are used in many environments due to their good softness and electrical conductivity,which is of great help to meet the needs of human society.As the application requirements in the information age become higher and higher,the expected values and idealized requirements for various performance parameters such as the range,accuracy,and stability of the measured information are gradually increased.Based on the principle of forced assembly,PDMS is used as the base of sensitive components and electrodes,and carbon fiber is added as a conductive filling medium to prepare a polymer-based piezoresistive flexible sensor,which effectively overcomes the difference between the conventional flexible sensor and the sensitive substrate and the electrode substrate.Deformation limitations and output instability.At the same time,combined with the sensor structure,based on the forced assembly theory,a comprehensive theoretical analysis of its conductive measurement mechanism is carried out.According to the sensor piezoresistive characteristic curve,the appropriate force range is selected,the sensor signal acquisition and processing system is designed,and the sensor output signal is sent to the upper computer.The process of interface display has been introduced and analyzed in detail.According to the specific use environment,analyze the possible influencing factors and determine the influence coefficient through experiments.Finally,the static and dynamic alternating loading implementation is carried out under the simulated working condition environment,and the accuracy and characteristics of the flexible sensor resistance output are analyzed under the designed signal acquisition and processing system.The experimental results show that the signal acquisition and processing system passes through a series of operations such as signal acquisition circuit,environmental parameter interference,amplification,filtering and zero drift compensation,and the dynamic alternating load is 10kN?60kN and the frequency is 3Hz,that is,the actual force range.Under the action of the flexible sensor resistance signal stable output,the peak,valley and output voltage of the output signal have a consistent phase.The dynamic and static experimental output resistance range is 310?624.15?,and the sensitivity range is 171-183N/?.The real-time output signal of the sensor can be completely consistent with the pressure curve,and the running state of the rail is effectively monitored to meet the project requirements.However,due to the hysteresis of the elastic recovery of the polymer,the output repeatability of the flexible sensor under the cyclic alternating load is 5.03%and 0.78%lower than that of the static load,respectively.Combined with the static and dynamic experiments,it is verified that the polymer-based flexible sensor can maintain the same deformation characteristics as the measured object,which overcomes the certain deformation and unsynchronization phenomenon of the flexible sensor due to the difference between the sensing element and the electrode structure,and simultaneously outputs and receives The force presents a resistance signal of the mapping relationship.The repeatability of the output signal under dynamic and static experiments is within±7%,which can meet the measurement requirements of the fatigue life of the measured body during cyclic loading.