Design And Experimental Research Of A Herringbone Biped Piezoelectric Robot

In recent years,with the rapid development of robot technology,small and micro robots are more and more used in the fields of bioengineering,military reconnaissance,micro-manipulation,optical precision tracking and so on.Intelligence,light weight,miniaturization,precision,multi-degree-of-freedom driving has become the key development directions of robot technology development.Piezoelectric actuator has the advantages of fast response,high resolution,simple structure and no electromagnetic interference,which provides a new direction for the technological breakthrough of small and micro robots.According to the structure,the piezoelectric robot can be divided into sandwich structure and patch structure.Although the former can achieve nanometer resolution,it generally has a larger volume and weight,which is not conducive to the lightweight of piezoelectric robots;The latter is easier to realize lightweight design,has low requirement for driving signal and is easy to realize multi degree of freedom topology.In order to realize the lightweight,multi degree of freedom driving and portable power supply of small and micro piezoelectric robot,a herringbone-shaped bipedal patch structure is designed,and an inertial driving mode excited by continuous sawtooth wave signal is planned.The feasibility of the design is verified by theoretical and experimental research.Firstly,this thesis analyzes the principle of stick-slip inertial driving for one-dimensional motion of a herringbone piezoelectric robot.On this basis,the configuration of a single driving foot and the arrangement of two driving feet are planned,and the excitation mode of the herringbone piezoelectric robot is determined.Based on the finite element simulation with ANSYS software,the relationship between the structural parameters,the excitation voltage and the output of the herringbone piezoelectric robot is determined,and the selection of various structural parameters and materials of the physical prototype is determined by this relationship.The first five resonant frequencies of the piezoelectric robot are obtained by modal analysis,which can be used as a reference for the selection of excitation signal.By establishing a dynamic model,the frequency response function of the robot's single-step displacement and velocity is obtained,which provides a theoretical basis for the design of piezoelectric robots of this type.By comparing the numerical simulation results of the dynamic model with the finite element analysis results,the accuracy of the kinetic model is verified.Secondly,according to the excitation signal type of the piezoelectric robot designed before,the compact driving power supply of the herringbone piezoelectric robot is developed.According to the actual requirements of the herringbone piezoelectric robot for the driving signal and the physical characteristics of the driving power,the overall design scheme and technical index of the driving power supply are proposed.The DC boost module and the linear amplifier circuit module of the driving power supply are simulated and designed by using Multisim simulation software.The circuit wiring design is completed by using the Lichuang EDA software,the prototype of driving power supply is manufactured and its input and output characteristics are tested.The test results show that the compact drive power designed in this thesis meets the design requirements of the herringbone piezoelectric robot.Finally,the physical prototype of the robot is developed.In order to expand the degree of freedom,a piezoelectric robot array which can be used to realize the motion of linear freedom and the rotation degree of freedom around the plane axis is presented.On this basis,the hardware and software design of attitude angle control scheme based on PID algorithm is completed.Two sets of experimental test systems are established,and the corresponding measurement scheme is constructed.Using the experimental test system,the output characteristics of the driving foot of the piezoelectric robot,the physical characteristics of a single piezoelectric robot and the physical characteristics of the piezoelectric robot array are studied respectively.The experimental results show that the output characteristic of the driving foot is good,the response time is less than 3ms,and the first resonance frequency is67.6Hz;the robot can walk on different materials;When the excitation signal is20V_p-p and 130Hz,the walking speed can reach 1.53mm/s and the single step displacement can reach 117?m,which means it has highe resolution and highe walking speed at the same time;And The motion speed of the piezoelectric robot array is approximately linear with the voltage amplitude;When the driving signal amplitude is 24V_p-p,the piezoelectric robot array can achieve the fastest motion speed of about 1333?m/s under 130Hz excitation;The piezoelectric robot array realizes the closed-loop control of attitude angle,and the response speed of the system is about 0.33°/s when it rotates counterclockwise.The response speed of clockwise rotation is about 0.22°/s.The steady-state error of clockwise rotation is about 8%,and that of counter clockwise rotation is less than 3%.The piezoelectric robot developed in this thesis is compared with the similar piezoelectric robot in recent years.The results show that the robot designed in this thesis has significant advantages in motion speed,structure size,multi degree of freedom motion topology,simple excitation mode and so on.