Research On Safety Control Of Robotic Arm Based On Flexible Skin With Distance And Pressure Sensing

With the unceasing improvement of industrial automation,information and intelligent level,robot technology has ushered in a rapid development,and the application field of robot has become very extensive,subsequently,the working environment of robot becomes complex and dynamic,especially in the human-robot collaboration,medical care and family service scenarios,interaction and even more contact between human and robot become more frequent;in the face of such a dynamic environment,the robot need the ability of perceiving environmental information to improve the reliability and security of the human-robot interaction.Therefore,based on the six DOF robotic arm developed by our laboratory,we design a flexible skin which can perceive distance and pressure information at the same time,which can realize the safe operation of robotic arm by combining the active and passive safety control method,and carry on the corresponding simulation and experiment.Aiming at the safety research of the robot arm,a new flexible sensitive skin is designed.The skin structure has certain elasticity,which can reduce the contact stress effectively when the robot arm contacts with people or objects.Pressure sensor and distance sensor are arranged inside the skin,which empowers the skin to perceive the surface force information of robot arm and surrounding distance information.Based on pressure sensor and distance sensor,robotic arm wrapped in the flexible skin can perceive the surrounding proximity and the size and location of the contact force,preparing to premise for the research of human-robot interaction safety control.In the study of active safety control,robotic arm can foresee danger,and take safety strategies to avoid it.Firstly,sensor signal is processed by particle filter(PF)and kalman filter(KF),diatance information is reduced noise by combineing the particle filter with kalman noise in the end.Finally,according to the valid data,robotic arm can avoid obstacles,pass the narrow space without contact and judge the speed of closing objects to take appropriate measures.In passive safety control,a simple spring-damp system,composed of elastic skin and robot arm,is the first barrier in the passive safety system,the second is observation of the collision force during human-robot interaction by using the flexible thin film pressure sensor in the skin.Then the information is used in the intentionally and unintentionally contact scenarios in order to enhance the security and intuitive of human and robot physical interaction.Finally,the skin prototype is integrated into the robotic arm,the experimental platform is set up,and the active and passive safety control method of robotic arm is to be carried out experimental study.The experimental study of robotic includes mainly the safety around/through and close to objects of robotic arm based on distance sensor and the intentionally and unintentionally contact of robotic arm based on the pressure sensor.Finally,the research is verified by simulation and experimental results in this paper.