Cam-Shaped Soft Gripper With PVDF/Graphene Piezoelectric Sensor

Abstract In the era of growing integration of intelligent sensors in automated systems, propelled by advancements in industrial automation and the Internet of Things (IoT). This paper presents an innovative polyvinylidene difluoride (PVDF)/graphene piezoelectric membrane sensor specifically designed for direct force measurement. The remarkable properties of the piezoelectric material enable direct utilization without polarization. With a flexible design for easy installation at contact points between components, the sensor is tailored to the geometric shapes of components, finding application in soft grippers for object manipulation. The proposed novel piezoelectric sensor undergoes systematic evaluation through standardized experiments, obtaining measurements of different force magnitudes and corresponding voltage signal variations. The collected data is utilized to establish fitting models, thereby enhancing the reliability of the sensor’s data. The coefficient of determination (R squared) is employed as a metric to assess the goodness of fit of the models. Additionally, experimental results provide insights into the applicable range and voltage variations of the piezoelectric sensor. This research integrates a piezoelectric membrane sensor into an innovative cam-shaped soft gripper made of polydimethylsiloxane (PDMS) and demonstrates its application in agricultural automation by measuring the clamping force in plant seedlings. This cam-shaped gripper incorporates a novel self-alignment concept in its mechanism, enhancing its efficiency and mitigating potential damage to plant seedlings during the clamping process. Experiments with cam-shaped soft grippers demonstrate minimal deviation in gripping force.