Optical Design And Experimental Study Of Capacitive Six-dimensional Force Sensor

As one of the most important sensors in robot intelligent and humanized applications,multi-dimensional force/torque sensor provides force information for robot motion control,which is an important part of robot technology motion control.The common multi-dimensional force/torque sensor is mainly resistance strain gauge type,but the strain gauge attachment process is complicated and subject to mechanical wear,which will have certain influence on the measurement results.In this paper,a capacitive multi-dimensional force/torque sensor is designed.The structure and measurement principle of the sensor are given.The decoupling feasibility of the sensor is analyzed by calculation and simulation.The calibration of the capacitance hardware detection circuit and the multi-dimensional force sensor is designed.The platform determines the force/torque loading method.This paper’s main research contents are as follows:(1)Analyze the research status of multi-dimensional force/torque sensors at home and abroad,and analyze the development trend and application prospects of capacitive multi-dimensional force sensors;(2)Comparing the measurement principle of variable pole distance parallel plate,variable area parallel plate,variable medium parallel plate and capacitor based on capacitive edge effect variable pole vertical plate capacitor,the calculation formulas of sensitivity and theoretical linearity of different measurement principles are determined.The advantages and disadvantages of different measurement principles are analyzed.Considering the factors of mechanical structure,the measurement principle of the combination of variable pole parallel plate and capacitive edge effect variable pole vertical plate is selected as the design principle of this paper.(3)The structural design of the six-dimensional force sensor is carried out by finite element analysis.A serpentine beam structure is proposed as the elastic body of the sensor.The structure is more consistent with the effective deformation generated by the full-scale force.For each of the six-dimensional force sensors The stress check was carried out,and the calculation modal analysis was carried out to determine the working frequency band of the sensor.The decoupling of the designed six-dimensional force sensor was qualitatively analyzed and simulated by finite element simulation.Experiments verify the feasibility of decoupling the designed six-dimensional force sensor.(4)Contrasting and analyzing the traditional capacitance detection circuit,for the problems of low precision,obvious drift and easy to be affected by the scattered capacitance,the ADI capacitor digital conversion chip is selected as the capacitance detection scheme of the multi-dimensional force/torque sensor,and the capacitor is designed.The circuit schematic diagram and the hardware circuit the capacitor is designed.The circuit schematic diagram and the hardware circuit board(PCB)are tested,so that the designed capacitive multi-dimensional force sensor has certain anti-interference ability and high integration degree;the sensor static plate is designed according to the mechanical body structure of the sensor,wherein the static electrode of the vertical electrode The board uses a double-layer parallel plate,which increases the sensitivity of the sensor to some extent.The through hole on the designed PCB is slightly larger than the mounting screw,so that the sensor can adjust the initial pole pitch of the vertical plate through the feeler gauge,which can avoid certain errors caused by processing and installation,and the sensitivity of the sensor has certain adjustability;(5)By comparing and analyzing the calibration methods of various multidimensional force/torque sensors,it is determined that the calibration platform of multi-dimensional force/sensor is designed by using the weight calibration platform,and the loading method of each dimension force is analyzed.And static decoupling experiments were carried out on the designed sensors to verify the decoupling feasibility of the sensors.The linearity of the final designed sensor is less than 3.5%,and the decoupling error is less than 3%F.S.