CN110321572B - Pipeline crawling robot system analysis and verification method - Google Patents

Abstract

Translated fromChinese

本发明涉及一种管道爬行机器人系统分析与验证方法，在三维建模软件中建立机器人本体结构的三维模型；对三维模型采用六面体网格进行网格划分，将得到的机器人本体有限元模型导入进ADAMS中进行分析设置；在ADAMS中，对压电陶瓷驱动器施加电压信号，使机器人本体有限元模型产生向前位移；在MATLAB中，对压电陶瓷驱动器施加电压信号，使机器人本体有限元模型产生向前位移，与在ADAMS中向前位移一致。本发明管内移动机器人是以压电双层膜为基本结构，利用惯性冲击原理达到运动的目的。结构简单，操作方便易于实现，可在软、硬狭小的管道内进行移动，可在恶劣的工况下工作，有良好的发展前景。

The invention relates to a system analysis and verification method of a pipeline crawling robot. A three-dimensional model of the robot body structure is established in three-dimensional modeling software; The analysis settings are performed in ADAMS; in ADAMS, a voltage signal is applied to the piezoelectric ceramic driver, so that the finite element model of the robot body generates forward displacement; in MATLAB, a voltage signal is applied to the piezoelectric ceramic driver to generate the finite element model of the robot body. Forward displacement, consistent with forward displacement in ADAMS. The mobile robot in the tube of the invention takes the piezoelectric double-layer membrane as the basic structure, and uses the principle of inertial impact to achieve the purpose of movement. The structure is simple, the operation is convenient and easy to implement, it can be moved in soft and hard narrow pipes, and it can work in harsh working conditions, and has a good development prospect.

Description

Pipeline crawling robot system analysis and verification method

Technical Field

The invention relates to the field of pipeline crawling robot system analysis, in particular to a pipeline crawling robot system analysis and verification method.

Background

Various micro pipelines are used in thermal power plants, nuclear power plants, chemical plants, civil buildings and the like, and the safe use of the micro pipelines needs regular maintenance. However, due to the limitation of narrow space, automatic maintenance has certain difficulty. Only taking a nuclear power station as an example, the pipeline with the inner diameter of about 20mm has a plurality of pipelines, and the labor condition of workers is severe when the reactor is stopped and checked. Therefore, the research and application of the robot automatic inspection technology in the micro-pipeline are necessary. The micro robot can move back and forth in the soft and hard narrow pipelines, can be loaded with sensors such as a camera and the like for detection, and can be applied to medicine such as digestive tract detection or industry such as nuclear power station micro pipeline crack detection.

At present, various countries have certain research, such as: japanese DENSO developed a micro-robot for the automated detection of small industrial pipelines in 1995. The robot mainly comprises a support body, an inertia block and an elastic support leg, and is designed according to the inertia impact principle on the basis of the inverse piezoelectric effect. And people have studied domestically, such as: "integrated system of small industrial pipeline robot mobile detector" developed by Shanghai university (precision mechanical engineering system) includes: the robot mechanism and the control technology (including a spiral wheel moving mechanism, a planet wheel moving mechanism, a piezoelectric plate driving moving mechanism and the like), the robot in-pipe position detection technology, the eddy current detection and the video detection application technology in the industrial pipeline with the inner diameter of 20mm are vertically arranged, and an in-pipe automatic detection robot system is formed on the basis. The system can realize the mobile detection of cracks and defects in the 20mm pipeline. Most of the robots adopt an inertial impact type motion principle, and at present, extensive theoretical and experimental researches are carried out on the driving principle at home and abroad, but the researches are not comprehensive and deep enough.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a pipeline crawling robot system analysis and verification method.

The technical scheme adopted by the invention for realizing the purpose is as follows:

a pipeline crawling robot system analysis and verification method comprises the following processes:

step 1: establishing a three-dimensional model of a robot body structure in three-dimensional modeling software;

step 2: carrying out mesh division on the three-dimensional model by adopting a hexahedral mesh, and importing the obtained finite element model of the robot body into ADAMS for analysis and setting;

and step 3: in ADAMS, a voltage signal is applied to a piezoelectric ceramic driver, so that a finite element model of a robot body generates forward displacement;

and 4, step 4: in MATLAB, applying a voltage signal to a piezoelectric ceramic driver to enable a finite element model of a robot body to generate forward displacement, judging whether the forward displacement is consistent with the forward displacement in ADAMS, and if so, verifying to be true; otherwise, returning to thestep 2.

The three-dimensional model of the robot body structure comprises: a rigid frame at the periphery of the bimorph piezoelectric film and a moving support mechanism which is formed by elastic support legs fixedly connected with the rigid frame.

The bimorph piezoelectric film is formed by bonding piezoelectric ceramic sheets on two sides of an elastic metal sheet, is consistent with a rigid frame on the periphery of the bimorph piezoelectric film in shape and is circular or regular polygon, and 3-4 circular through holes are axially and uniformly distributed near the edge.

The elastic supporting legs are elastic steel wires and penetrate through the rigid frame and the circular through holes of the bicrystal piezoelectric film to be fixedly connected with the rigid frame and the circular through holes of the bicrystal piezoelectric film.

The analysis settings include settings for materials, properties, boundary conditions, and application of loads.

The load is applied by applying an impact load to the bimorph piezoelectric film.

The step of applying a voltage signal to the piezoelectric ceramic driver to enable the finite element model of the robot body to generate forward displacement comprises the following steps:

step 1: applying pressing force on the robot and the pipe wall, and generating friction force when the robot moves relative to the pipe wall;

step 2: the driving voltage is gradually applied to the piezoelectric ceramic driver to make the mass block move forward;

and step 3: when the acceleration of the mass block is larger than the friction force of the pipe wall to the robot, the robot body moves forwards.

The judging whether the forward displacement is consistent with the forward displacement in the ADAMS comprises the following steps:

and if the forward displacement output in the MATLAB and the forward displacement error output in the ADAMS are smaller than a set error threshold value, judging that the forward displacement and the ADAMS are consistent, and otherwise, judging that the forward displacement and the ADAMS are inconsistent.

The invention has the following beneficial effects and advantages:

1. the robot moving in the pipe takes a piezoelectric double-layer film as a basic structure and achieves the aim of movement by utilizing the inertial impact principle. The structure is simple, the operation is convenient and the realization is easy;

2. the invention can move in the soft and hard narrow pipelines and can work under the severe working conditions;

3. the ADAMS is adopted for analog simulation, the contact analysis units of the contact surfaces of the robot supporting leg and the pipe wall are divided by adopting the surface-surface contact units TARGE170 and CONTA174, and the result shows that the structure has enough strength;

4. compared with simulation results of MATLAB/Simulink modules, ADAMS software has the advantages that the result error is small, the orders of magnitude are completely consistent, and the reliability is good;

5. the invention has good development prospect in the field of micro-robots.

Drawings

FIG. 1 is a graphical representation of a robot mathematical model of the present invention;

FIG. 2 is a view of the robot body structure of the present invention;

FIG. 3 is a cloud of finite element simulated displacement and stress of the present invention;

FIG. 4 is a waveform diagram of the forward and reverse of the robot of the present invention;

FIG. 5 is a block diagram of the control system of the present invention;

FIG. 6 is a schematic diagram of a system simulation of the present invention;

FIG. 7 is a graph of the shift in ADAMS for the present invention;

FIG. 8 is a graph of the displacement of the present invention in MATLAB;

wherein, 1 is inertial mass block, 2 is bimorph piezoelectric film, 3 is the dabber, 4 is the piezoelectricity backup pad, 5 is the elastic support leg.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

The invention provides a pipeline crawling robot system, wherein an inertial impact driver consists of a mobile positioning body, a piezoelectric ceramic driver and a mass block, one micro-displacement period of the inertial impact driver is divided into 2 phases, the 2 phases of motion are repeated, and the inertial impact driver can realize continuous forward (backward) motion. A method for analyzing and verifying a pipeline robot system mainly comprises a structure design module, a control design module and a finite element simulation.

The mechanical structure module, a miniature linear driver based on the bicrystal piezoelectric film, comprises a driving mechanism which is sleeved on a central shaft, one end or two ends of the driving mechanism are respectively positioned by an inertia mass block and a fixed sleeve, and the middle of the driving mechanism is isolated by an insulating isolation sleeve to form a plurality of bicrystal piezoelectric films, and a mobile supporting mechanism which is formed by a rigid frame at the periphery of the bicrystal piezoelectric films and elastic supporting legs fixedly connected with the rigid frame; the bimorph piezoelectric film is formed by bonding piezoelectric ceramic sheets on two sides of an elastic metal sheet, and is characterized in that the bimorph piezoelectric film and a peripheral rigid frame are corresponding to be round, or a regular quadrangle or a regular polygon, and 3-4 small round through holes are uniformly distributed in the circumferential direction near the edge; the elastic supporting legs are elastic steel wires and penetrate through the rigid frame and the small through holes of the circular holes of the bimorph piezoelectric films to be fixedly connected with the rigid frame and the small through holes of the circular holes of the bimorph piezoelectric films.

The control module achieves the purpose of motion driving by utilizing the inertial impact principle. The robot is mainly formed by connecting a piezoelectric double-layer film structure and an inertial mass in series through a brass shaft. When working voltage is applied, each piezoelectric double-layer film can deform, and the deformation is converted into linear displacement of the integral structure by the inertial impact mechanism. The movement process is as follows:

firstly, pre-applying initial pressing force on the robot and the pipe wall, so that when the robot moves relative to the pipe wall, a friction force is generated;

in the second step, a driving voltage is gradually applied to the piezo-ceramic driver, and the mass moves forward due to the growth of the piezo-ceramic due to the piezo-effect, as shown in the process of fig. 1 (a → b). Because the acceleration is small, the reaction force of the mass block to other parts of the robot is smaller than the friction force of the pipe wall to the robot, and the robot body is kept still;

thirdly, when the driving voltage jumps from b to a, in the process (b → a) of fig. 1, the mass block approaches the piezoelectric ceramic driver at a large acceleration, and the reaction force of the mass block to the robot body is far greater than the friction force of the pipe wall to the body, so that the robot body generates forward displacement; the above processes are circularly reciprocated to realize the motion of the robot.

The piezoelectric ceramic driver inputs sawtooth waves with two shapes to realize the forward and backward movement of the robot. The parameter range of the input voltage signal of the piezoelectric ceramic driver. The amplitude is adjustable between 0 and + 150V; the frequency should be between 10Hz and 10 kHz.

The control system structure of the robot is in the form of an upper computer and a lower computer, the upper computer is a PC (personal computer), the lower computer is a designed robot driving device, and the communication between the upper computer and the lower computer is RS232C serial port communication. The upper computer is used for providing a human-computer interface and sending a control command of the robot to the lower computer through the RS232 serial port. And after receiving the command, the lower computer interprets the command, generates a waveform and amplifies the waveform to drive the piezoelectric ceramics of the robot.

To verify the reliability of the present invention, the present system was simulated by MATLAB. The body of the robot can realize the movement under the drive of a given signal under the action of a drive signal.

Fig. 1 shows a mathematical model of the robot of the present invention.

By providing a voltage triangle wave, the inertial mass is subjected to a vibration excitation. During the vibration of the mass block, when the inertia force is large enough to overcome the friction force between the elastic legs and the pipe wall, the robot body moves forwards for a certain distance. Wherein the maximum static friction coefficient between the elastic legs and the pipe wall is 0.4, and the dynamic friction coefficient is 0.2. Here, F is the amplitude of the vibration force generated by the bimorph actuator. Its value can be obtained according to the specifications of the bimorph actuator and the related derivations. The simulation here may take a driving force of 0.2N.

Fig. 2 is a view showing a structure of a robot body according to the present invention.

The method mainly comprises the following steps: the piezoelectric actuator comprises 3 elastic supporting legs, 4 piezoelectric supporting plates, 2 piezoelectric film drivers, a mandrel and an inertial mass block. Two piezoelectric film drivers are connected in series through a mandrel, and an inertia block and an elastic supporting leg with certain mass are configured, so that the mobile robot in the small tube can be formed. The robot can move by adopting a piezoelectric film drive and utilizing an inertial impulse type motion principle (IDM). The IDM driving principle has the following advantages: a large range of motion (in centimeters) can be achieved; the resolution can reach the nanometer level; simple structure and easy realization. The driving principle is applied to research and development of a novel driver based on piezoelectric driving.

FIG. 3 is a cloud diagram of finite element simulated displacement and stress of the present invention; wherein (a) is a finite element simulation displacement diagram, and (b) is a stress cloud diagram.

The contact analysis unit division is carried out on the contact surface of the robot supporting leg and the pipe wall by adopting a surface-surface contact unit TARGE170 and a CONTA 174. The total number of units is 2057, the total number of nodes is 14068, and the most degree of freedom of a single node is 4. From fig. 3(a) we can see that: the maximum displacement of the robot after being subjected to the impact load of the vibration of the piezoelectric film is 7.7385 microns, and the maximum Von Mises stress of the robot is only 37.962 MPa. Much less than the yield strength of piezoceramic materials. Therefore, the structural strength of the robot can be deduced to be enough, so that the robot body cannot be damaged in the moving process. In order to prevent the robot from resonating due to the vibration excitation of the piezo film driver, we analyzed its order frequencies. The first 10 frequencies, 356.6, 356.84, 667.3, 914.45, 916.42, 1450.3, 1731.5, 1829.8, 1844.5, 3731.7 are given here. The fundamental frequency can be seen to be 356.6 Hz. For this reason, the external excitation frequency should be kept away from this value as much as possible. Through carrying out statics analysis and modal analysis to robot mechanism, verified the exactness of inertia impact type motion principle to and the validity of this principle application in intraductal walking miniature robot.

Fig. 4 is a waveform diagram illustrating forward and backward movements of the robot according to the present invention; wherein (a) is a forward waveform diagram and (b) is a backward waveform diagram.

The initial pressing force is pre-applied to the robot and the pipe wall, so that when the robot moves relative to the pipe wall, a friction force is generated; the driving voltage is gradually applied to the piezo-ceramic driver, and the mass moves forward due to the piezo-effect as the piezo-ceramic grows in the process (a → b) of fig. 4 (a). Because the acceleration is small, the reaction force of the mass block to other parts of the robot is smaller than the friction force of the pipe wall to the robot, and the robot body is kept still; when the driving voltage jumps from b to a, in the process (b → a) of fig. 4(a), the mass block approaches the piezoelectric ceramic driver at a large acceleration, and the reaction force of the mass block to the robot body is far greater than the friction force of the pipe wall to the body, so that the robot body generates forward displacement; the above processes are circularly reciprocated to realize the motion of the robot.

Fig. 5 is a block diagram of the control system of the present invention.

The control system structure of the robot is in the form of an upper computer and a lower computer, the upper computer is a PC (personal computer), the lower computer is a designed robot driving device, and the communication between the upper computer and the lower computer is RS232C serial port communication. The upper computer is used for providing a human-computer interface and sending a control command of the robot to the lower computer through the RS232 serial port. And after receiving the command, the lower computer interprets the command, generates a waveform and amplifies the waveform to drive the piezoelectric ceramics of the robot. The hardware drive control system adopts a C8051F040 high-speed singlechip of Cygnal company to realize the control of the FPGA waveform generator and realize the data communication between the driver and the upper computer; the generation of sawtooth waveforms is realized by adopting a Cyclone series FPGA chip and a DDS (direct digital frequency synthesis) technology of the American ALTERA company; the waveform amplification and output are achieved using a high voltage power operational amplifier PA90 from APEX corporation, usa.

Fig. 6 shows a schematic diagram of the system simulation of the present invention.

The body of the robot can realize the movement under the drive of a given signal under the action of a drive signal.

FIG. 7 is a graph showing the shift profile in ADAMS of the present invention.

The abscissa is a time axis in seconds (S), and the ordinate represents a moving distance in millimeters (mm).

Fig. 8 shows the displacement curve in MATLAB according to the invention.

The abscissa is a time axis in seconds (S), and the ordinate represents a moving distance in millimeters (mm).

Claims (4)

Translated fromChinese

1.一种管道爬行机器人系统分析与验证方法，其特征在于：包括以下过程：1. a pipeline crawling robot system analysis and verification method, is characterized in that: comprise the following process:步骤1：在三维建模软件中建立机器人本体结构的三维模型；Step 1: Establish a 3D model of the robot body structure in the 3D modeling software;所述机器人本体结构的三维模型包括：双晶压电薄膜外围的刚性框架以及与刚性框架固定连接弹性支撑脚构成的移动支持机构；The three-dimensional model of the robot body structure includes: a rigid frame on the periphery of the bimorph piezoelectric film and a moving support mechanism composed of elastic support feet fixedly connected with the rigid frame;所述的双晶压电薄膜是由弹性金属薄片的两面粘合压电陶瓷片构成，双晶压电薄膜与其外围的刚性框架形状一致，为圆形或正多边形，在靠近边缘有轴向均布的3～4个圆形穿孔；The bimorph piezoelectric film is composed of two sides of an elastic metal sheet bonded to piezoelectric ceramic sheets. The bimorph piezoelectric film has the same shape as its peripheral rigid frame, which is a circle or a regular polygon, and has axial uniformity near the edge. 3 to 4 circular perforations of the cloth;步骤2：对三维模型采用六面体网格进行网格划分，将得到的机器人本体有限元模型导入进ADAMS中进行分析设置；Step 2: Use hexahedral mesh to divide the three-dimensional model, and import the obtained finite element model of the robot body into ADAMS for analysis and setting;步骤3：在ADAMS中，对压电陶瓷驱动器施加电压信号，使机器人本体有限元模型产生向前位移；Step 3: In ADAMS, apply a voltage signal to the piezoelectric ceramic driver, so that the finite element model of the robot body is displaced forward;步骤4：在MATLAB中，对压电陶瓷驱动器施加电压信号，使机器人本体有限元模型产生向前位移，并判断该向前位移与在ADAMS中向前位移是否一致，如果一致，则验证成立；否则，返回步骤2；Step 4: In MATLAB, apply a voltage signal to the piezoelectric ceramic driver, so that the finite element model of the robot body generates a forward displacement, and judge whether the forward displacement is consistent with the forward displacement in ADAMS. If it is consistent, the verification is established; Otherwise, go back to step 2;所述对压电陶瓷驱动器施加电压信号，使机器人本体有限元模型产生向前位移包括以下步骤：The applying a voltage signal to the piezoelectric ceramic driver to make the finite element model of the robot body generate forward displacement includes the following steps:步骤1：在机器人和管壁上施加压紧力，当机器人相对管壁有运动趋势时，产生摩擦力；Step 1: Apply a pressing force on the robot and the pipe wall, when the robot has a tendency to move relative to the pipe wall, a friction force is generated;步骤2：驱动电压逐渐加到压电陶瓷驱动器上，使质量块向前运动；Step 2: The driving voltage is gradually added to the piezoelectric ceramic driver to make the mass move forward;步骤3：当质量块加速度大于管壁对机器人的摩擦力时，机器人本体向前移动；Step 3: When the acceleration of the mass block is greater than the frictional force of the pipe wall on the robot, the robot body moves forward;所述判断该向前位移与在ADAMS中向前位移是否一致，包括：The judging whether the forward displacement is consistent with the forward displacement in ADAMS includes:如果在MATLAB中输出的向前位移与在ADAMS中输出的向前位移误差小于设定误差阈值，则判定二者一致，否则不一致。If the forward displacement output in MATLAB and the forward displacement error output in ADAMS are less than the set error threshold, it is determined that the two are consistent, otherwise they are inconsistent.2.根据权利要求1所述的管道爬行机器人系统分析与验证方法，其特征在于：所述弹性支撑脚为弹性钢丝，贯穿刚性框架和双晶压电薄膜的圆形穿孔而与其固定连接。2 . The method for analyzing and verifying a pipeline crawling robot system according to claim 1 , wherein the elastic support feet are elastic steel wires, which penetrate the rigid frame and the circular perforations of the bimorph piezoelectric film and are fixedly connected to them. 3 .3.根据权利要求1所述的管道爬行机器人系统分析与验证方法，其特征在于：所述分析设置包括对材料、属性、边界条件进行设置以及载荷的施加。3 . The method for analyzing and verifying a pipeline crawling robot system according to claim 1 , wherein the analysis setting includes setting materials, properties, boundary conditions and applying loads. 4 .4.根据权利要求3所述的管道爬行机器人系统分析与验证方法，其特征在于：所述载荷的施加为对双晶压电薄膜施加冲击载荷。4 . The method for analyzing and verifying a pipeline crawling robot system according to claim 3 , wherein the load is applied by applying an impact load to the bimorph piezoelectric film. 5 .

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