| Force sensors are widely used in military equipments,medical equipments,automotive manufacturing,consumer electronics and robotics.The existing multi-dimensional force sensors are mainly decoupled by signal processing circuits or software algorithms,which requires complex software algorithms and interface circuit compensation technology.In view of the problems such as large volume,expensive price,poor decoupling effect and difficult mass producing of multi-dimensional force sensors,this thesis designs a self-decoupling multi-force signals sensor based on MEMS technology,which can measure force and moment signals of six-axis in space.This kind of sensor has the characteristics of low cross effect and resistance to dynamic environmental interference.The innovation of this thesis is that a novel and special sensor structure is designed,which can measure the six-axis force and moment signals,achieve self-decoupling without the help of algorithms.The main research contents completed in this thesis are as follows:（1）A six-axis force and moment capacitive multi-force signals sensor based on MEMS technology is designed,and its structure is optimized based on ANSYS software.The results show that the structure can achieve the measurement and decoupling of six-axis force and moment signals.The first-order natural frequency of the multi-force signals sensor is greater than 10000 Hz,the multi-force signals sensor also has a wide bandwidth and good anti-resonance ability.The measuring range of the triaxial force signals can reach 2.5 N and the measuring range of shear force signals can be overloaded to 8.5 N.The measuring ranges of X（Y）-axis moment and Z-axis moment are 14 m N·m and 200 m N·m respectively.The sensitivity of shear force and normal force are 0.1028 N-1and 139.99 f F/N respectively.The sensitivity of X（Y）-axis moment and Z-axis moment are 0.1482（m N·m）-1and 0.0016（m N·m）-1respectively.The shear force linearity of the sensor reaches 99.825%,the normal force linearity reaches 98.631%,the X（Y）-axis moment linearity reaches 99.89%and the Z-axis moment linearity reaches 99.97%.（2）The dynamic transmission characteristics of MEMS multi-force signals sensor are researched.The sensor displacement error caused by inertia is simulated and analyzed by applying acceleration signal to the mass block of the central boss.The results show that under the acceleration of 5g（g is the gravitational acceleration）,the total capacitance fluctuation of the sensor in the Z-axis direction reaches 0.08 f F.The total capacitance fluctuation reaches 0.24 f F in the X or Y-axis direction,proving that the sensor has the ability to resist the impact of 5g environment.（3）The effects of silicon layer thickness,U-beam width,initial distance between Z-axis plate and electrode on the main performance of the multi-force signals sensor are quantitatively researched.The results show that,when the thickness of silicon layer decreases from 290μm to250μm,the sensitivities of X（Y）and Z-axis force signals increase by 8.85%and 112.30%respectively.The sensitivities of X（Y）and Z-axis moment signals increase by 54.73%and 31.25%respectively.The overload measuring capability of X（Y）force signals of sensor is reduced by31.25%,the maximum measuring ranges of X（Y）and Z-axis moment signals are reduced by39.28%and 12.50%respectively.When the width of U-beam decreases from 70μm to 50μm,the sensitivities of X（Y）and Z-axis force signals increase by 184.20%and 114.44%respectively.The sensitivities of X（Y）and Z-axis moment signals increase by 57.71%and 237.50%respectively.The overload measuring capability of X（Y）-axis force signal of the sensor is reduced by 64.71%,and the maximum measuring range of Z-axis force signal is reduced by 20.00%.The maximum measuring ranges of X（Y）and Z-axis moment signals of the sensor are reduced by 14.28%and 50.00%respectively.When the initial distance between Z-axis plate and electrode is reduced from 70μm to 60μm and 50μm,the Z-axis initial capacitance of the sensor increases by 12.60%and 32.48%respectively.The sensitivity of Z-axis force signal increases by 53.05%and 157.88%respectively.The measuring linearity of Z-axis force signal is reduced by 1.44%and 3.87%respectively.（4）The process flow of MEMS multi-force signals sensor is designed,the process flow diagram is drawn,the steps and details of process flow are optimized.In addition,the processing layout of the multi-force signals sensor is drawn based on L-edit software. |
