Research On Slip Sensing Technology Based On Magneto-piezoresistive Effect

The slip sensor is an intelligent bionic sensor,which is mainly used to detect slip information between the manipulator and the object being grasped.As one of many sensors,it can detect the slip of the object and convert the slip information into electrical signals that can be collected and analyzed.The manipulator control system judges the sliding state of the object through the electrical signal fed back by the slip sensor,and drives the manipulator The flexible grasping of objects makes the manipulator intelligent,thereby extending the field of exploration and facilitating people's lives.According to the sensing mechanism of the slip sensor,it can be divided into: acousto-electric,capacitive,light-sensitive,laser and machine vision slip sensors.Among them,the acoustic-electric slip sensor is caused by the diaphragm structure of the sensitive unit.Its anti-interference ability is weak;capacitive slip sensors are greatly affected by temperature;laser and machine vision slip sensors have poor environmental adaptability.These shortcomings make it difficult for slip sensors to be popularized and applied in actual production and life.Slip sensor technology has also become a card-neck technology that restricts the development of my country's smart industry.It is urgent to develop a slip sensor based on new materials,new sensitive units,and new sensing mechanisms.This paper analyzes and summarizes the shortcomings of the existing slip sensor,and develops a slip sensor based on the magneto-piezoresistive effect as the sensing mechanism.This slip sensor sensitive unit adopts new materials and new sensing mechanisms to improve the sensor's anti-interference ability,piezoresistive linearity and sensitivity;a brand-new finger-type slip sensor housing is designed to reduce the impact of poor rigidity on the slip sensor.The impact of sensory characteristics.The main research contents are:Firstly,the preparation process of the magneto-piezoresistive sensitive unit was optimized: mainly studied the influence of magnetic particle settling,demoulding,bubble removal,curing agent content,silicone oil content and magneto-induced chain formation on the sensing characteristics of the sensitive unit.The sedimentation characteristics of magnetic particles were analyzed and researched,and the sedimentation phenomenon of magnetic particles was effectively improved by increasing the initial viscosity;a new type of sensitive unit preparation mold was designed,and the preparation efficiency of the sensitive unit was improved through a multi-cavity method,and the mold cavity was increased.The draft angle improves the demoldability of the sensitive unit and the smoothness of the surface of the sensitive unit;through experiments,the ratio of curing agent and silicone oil in the sensitive unit is optimized to improve the quality of the sensitive unit;the principle of debubbling air bubbles is analyzed and passed many tests.The secondary adjustment of the bubble discharge pressure improves the bubble elimination rate.Then,a more detailed analysis of the chaining process and principle of the magnetic particles during the curing process of the sensitive unit was carried out,and it was found that the fixed magnetization method was unreasonable.Through the ring current theory and Stokes equation,the force of magnetic particles in viscous liquid is better explained,and the dynamic force model of magnetic particles in the process of magnetic chaining is established.The new dynamic mechanical model can derive the time equation of the external magnetic field.The magnetic particles control the magnetic field according to the time equation of the external magnetic field for magneto-linking.The integrity of the conductive magnetic chain in the finished sensitive unit is improved,thereby improving the conductance of the sensitive unit Rate and linearity of the piezoresistive curve.Then carry out packaging test on the slip sensor: the package adopts pre-compression packaging to encapsulate,put the encapsulated sensitive unit into the slip sensor housing,and test the sensitivity,repeatability,resolution,linearity and other indicators of the sensitive unit,And finally calibrate the slip sensor.Finally,the application of the slip sensor: design a new manipulator,install the slip sensor on the manipulator for grasping experiments,analyze the sensor signal during the grasping experiment,and the signal feedback from the gliding sensor tends to be when the grasping force is constant.Stable.When the object being grasped by the manipulator slips during the lifting process,the signal fluctuates,and the grasping force is increased according to the magnitude of the signal fluctuation until the grasped object no longer slips,achieving the purpose of flexible grasping.