Piezoelectric-driven outer pipeline climbing robot and driving method thereofTechnical Field
The invention relates to the technical field of pipeline robots, in particular to a piezoelectric driven outer pipeline climbing robot and a driving method thereof.
Background
The small-diameter metal or PE pipe has wide application in modern industry and urban construction due to the characteristics of light weight, corrosion resistance, high pressure resistance and the like. These pipes are commonly used in a number of fields such as water supply, drainage, gas transportation, chemical pipelines, agricultural irrigation, and cable protection. They not only improve the delivery efficiency, but also reduce maintenance costs and potential leakage risks due to their good tightness and durability. However, even high quality tubing may suffer from performance degradation due to environmental factors, material aging, or construction damage as the service time increases. Periodic inspection and inspection is critical to ensure safe operation of the piping system. It can discover potential problems such as corrosion, cracks, blockage or other structural damage in time, thereby avoiding serious consequences such as leakage, explosion or service interruption which can be caused. In view of this, the research of the outer pipeline climbing robot is particularly important. These robots can be moved along the pipe automatically or semi-automatically, and the pipe is inspected comprehensively using built-in sensors and cameras. The outer pipeline climbing robot may perform tasks more efficiently and more safely than traditional inspection methods, especially in difficult to reach or dangerous environments. They can reduce labor costs, reduce operational risks, and provide more accurate inspection data.
At present, the outer pipeline climbing robots are various in types and can be divided into rolling type, clamping type, bionic type and adsorption type according to clamping modes. Suction robots, however, generally rely on vacuum suction or magnetic suction, limiting their environment of use. Wheeled robots are mainly designed for cylindrical climbing poles, with weak climbing capacity for rectangular or other polygonal surfaces. The foot clamping robot requires the use of a large motor and a complex transmission mechanism to achieve sufficient load capacity.
Based on the above-described drawbacks of the robots, piezoelectric driving robots have been developed. Compared with the traditional motor and pneumatic element, the piezoelectric driver has the characteristics of high efficiency, high precision, outage self-locking, quick response capability, low noise, electromagnetic interference resistance and the like, so that the robot can perform accurate position and speed control, and the accuracy and the safety of a detection task are very important. The pressure point driving transmission is simple and efficient, a more compact and simple structural design can be realized, flexible operation in a narrow pipeline space is facilitated, the maintenance cost is reduced, and electromagnetic interference is avoided. Furthermore, the piezoelectric driver is capable of achieving a wide variety of motion patterns, including bending and torsion, which provides great flexibility in the actuation of the robot in complex pipe structures. In view of this, the piezoelectric driven small outer pipe climbing robot exhibits great advantages in terms of improving pipe detection efficiency, reducing maintenance costs, and enhancing environmental adaptability of the robot.
However, the existing piezoelectric driven robot has a single property and can only be used for a pipeline with a specific size and a specific shape, which brings great limitation to the detection work of the robot. Therefore, a piezoelectric driving robot which is suitable for pipelines with various sizes and shapes and has high stability is urgently needed.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide the outer pipeline climbing robot driven by piezoelectricity and the driving method thereof, and the high speed, the quick response and the high positioning precision of the robot in the pipeline are realized by adopting the piezoelectricity driving technology. Through crescent breach crawling tooth and elastic clamping structure's design, promoted the adaptability of robot to different pipeline shapes and sizes by a wide margin.
In order to achieve the above object, the present invention is realized by the following technical scheme:
The first aspect of the invention provides a piezoelectric driven outer pipeline climbing robot, comprising a transducer unit,
The transducer unit comprises a vibration mechanism and a crawling mechanism, the vibration mechanism comprises a vibration body and piezoelectric ceramic plates, a plurality of piezoelectric ceramic plates are arranged on the upper surface of the vibration body, the crawling mechanism is arranged on the lower surface of the vibration body, the crawling mechanism comprises a plurality of crawling teeth, the distance is set between the crawling teeth at intervals, the vibration body is excited to vibrate by applying excitation voltage to the piezoelectric ceramic plates, and the crawling teeth are further driven to move to the ground, so that the climbing process of the robot is realized.
Further, the transducer unit further includes a mounting roller including a front side roller and a rear side roller, which are mounted at the front end and the rear end of the vibrator, respectively, the mounting roller being used for fixing the chucking mechanism.
Still further, still include fixture, fixture includes two upper and lower fixed loading boards, installs a transducer unit through the installation roller on two fixed loading boards respectively, connects two fixed loading boards through the screw, utilizes spring and nut to fix the screw.
Further, the vibrator is made of an alumina material.
Furthermore, the upper surface of the vibrator is stuck with two longitudinal vibration piezoelectric ceramic plates with the same specification through a coupling agent.
Further, the longitudinal vibration piezoelectric ceramic plates are polarized along the thickness direction, and the two piezoelectric ceramic plates are arranged in the same direction.
Further, the crawling teeth are triangular prism-shaped, one rectangular surface is connected with the lower surface of the vibrating body, and an arc blade structure is adopted in the middle of the edge contacted with the ground.
The second aspect of the invention provides a driving method of the piezoelectric driven outer pipeline climbing robot of the first aspect, comprising the following steps:
applying excitation voltage with the same amplitude and the same frequency to the piezoelectric ceramic plate to excite the vibration body to vibrate;
according to the task requirement, adjusting the phase difference of excitation voltage between the piezoelectric ceramic plates to drive the crawling teeth to move to the ground by the vibrating body;
after use is completed, the excitation voltage is turned off, and the transducer unit is reset.
Further, when the phases of the two excitation signals are 180 degrees different from each other, the front piezoelectric ceramic plate is elongated in the length direction, the rear piezoelectric ceramic plate is shortened in the length direction, when the front piezoelectric ceramic plate is shortened in the length direction, the rear piezoelectric ceramic plate is elongated in the length direction, and under the excitation of the two piezoelectric ceramic plates, the vibration body is promoted to complete second-order bending vibration, and meanwhile the crawling teeth are driven to move to the ground, so that the transducer unit moves backwards.
Further, when the phase difference is 0 degree, the piezoelectric ceramic plates on the front side and the rear side act identically, so that the vibration body is promoted to complete third-order bending vibration, and meanwhile, the crawling teeth are driven to move to the ground, so that the transducer unit moves forwards.
The one or more of the above technical solutions have the following beneficial effects:
The invention discloses a piezoelectric-driven outer pipeline climbing robot and a driving method thereof, and designs a piezoelectric-driven small outer pipeline climbing robot aiming at the problems of large volume, low positioning accuracy, insufficient application scene and the like of the existing outer pipeline climbing robot. By adopting the piezoelectric driving technology, the high speed, the quick response and the high positioning precision of the robot in the pipeline are realized. The improvement effectively solves the problem that the transmission structure is bloated in the traditional driving system, obviously reduces the volume of the robot in pipeline climbing, improves the adaptability and control precision of the robot, and meets the accurate detection requirement in a complex environment. In addition, the same-mode variable-order actuation mode of the frequency-conversion phase-modulation excitation piezoelectric transducer unit is adopted, so that the driving and configuration of the robot are simplified. This design reduces errors in the manufacturing and assembly process, making the robotic system simpler and more reliable. The improvement not only improves the controllability of the system, but also simplifies the system integration under multiple application scenes, and greatly improves the application flexibility of the robot in different working environments.
The invention adopts the arc blade structure similar to the crescent notch on the crawling tooth of the crawling tooth, and the designed crescent notch crawling tooth and the elastic clamping structure greatly improve the adaptability of the robot to different pipeline shapes and sizes. The crescent notch crawling tooth can effectively grasp pipes of various shapes such as round pipes or square pipes, and the elastic clamping structure enables the robot to work stably on the pipes of different pipe diameters. The design enhances the applicability of the robot, so that the robot can efficiently work under various pipeline conditions, thereby widening the application range of the robot and meeting the requirements of different pipeline detection and maintenance tasks.
Additional aspects of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.
Fig. 1 is a schematic diagram of the overall structure of an outer pipeline climbing robot driven by medium voltage electricity in the first embodiment of the invention;
FIG. 2 is a schematic view of an arc blade structure of a crawling tooth according to a first embodiment of the present invention;
FIG. 3 illustrates the same-mode variable-order actuation principle of a transducer unit according to a first embodiment of the present invention;
FIG. 4 is a diagram illustrating second order bending vibrations in a bi-directional vibration mode according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of third-order bending vibration in a bi-directional vibration mode according to an embodiment of the present invention;
FIG. 6 is a schematic diagram illustrating a combination of a transducer unit and a clamping mechanism according to a first embodiment of the present invention;
wherein, 1, a vibrator, 2, a piezoelectric ceramic plate, 3, crawling teeth, 4, a mounting roller, 5 and an upper energy converter unit, 6, a lower transducer unit, 7, a fixed bearing plate, 8, screws, 9, springs, 10 and nuts.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof;
Embodiment one:
The first embodiment of the invention provides a piezoelectric driven outer pipeline climbing robot, which comprises a transducer unit and a clamping mechanism, wherein the transducer unit comprises a vibration mechanism and a crawling mechanism as shown in fig. 1.
The vibration mechanism comprises a vibration body 1 and a piezoelectric ceramic piece 2, wherein the vibration body 1 is made of an aluminum oxide material and can be elastically deformed according to vibration, specifically, aluminum oxide is used as a material, ceramic parts are fired and cut into ceramic parts according to the size requirement to serve as the vibration body, and piezoelectric ceramics are adhered to the surface of the aluminum oxide ceramics. Compared with the vibration body made of the traditional stainless steel material, the vibration body can output larger motion displacement, response speed and other motion performances with smaller driving voltage, so that the condition of generating an excitation signal is reduced, and the system integration is facilitated. The upper surface of the vibrator 1 is provided with a plurality of piezoelectric ceramic plates 2, and specifically, the upper surface of the vibrator 1 is stuck with two longitudinal vibration piezoelectric ceramic plates 2 with the same specification through a coupling agent. The longitudinal vibration piezoelectric ceramic plates 2 are polarized along the thickness direction, and the two piezoelectric ceramic plates 2 are arranged in the same direction. The condition of the excitation of the second-order bending vibration mode and the third-order bending vibration mode of the vibrator 1 is met in the space position of the piezoelectric ceramic plate, the second-order bending vibration mode and the third-order bending vibration mode are selected to obtain larger displacement than the higher-order mode, and the novel material alumina is selected to be used as the vibrator 1, so that the defect of low resonance frequency of the second-order bending vibration mode and the third-order bending vibration mode is overcome, and more excellent motion performance is achieved. The two piezoelectric ceramics are adhered to fully utilize the surface space of the vibrator 1 and increase the adhering quantity of the piezoelectric ceramics 1. Compared with one piece of piezoelectric ceramic, the two pieces of piezoelectric ceramic can excite larger displacement, so that the performance of the miniature tube climbing robot is optimized. If three piezoelectric ceramics are used, on one hand, the requirement of electric signals is increased, the phase difference of the three piezoelectric ceramics needs to be controlled more accurately, and on the other hand, the second limited space is that the two piezoelectric ceramics fully utilize the surface space, and if the number of the piezoelectric ceramics needs to be increased, the overall size is increased, so that the original purpose of the micro-robot is overcome. Therefore, the invention adopts two piezoelectric ceramics, which can improve the force and power density of the standing wave actuator and improve the speed and load performance of the actuator. In other scenarios, the number of piezoceramics may be adaptively transformed as desired.
The embodiment adopts the piezoelectric driving to design the outer pipeline climbing robot, realizes high speed, quick response and high positioning precision of the robot, and solves the problems of large size, poor adaptability, low control precision and the like of the climbing robot caused by bulkiness of a transmission system.
The lower surface of the vibrating body 1 is provided with a crawling mechanism, the crawling mechanism comprises a plurality of crawling teeth 3, the whole design has prismatic characteristics, and specifically, as shown in fig. 2, the crawling teeth 3 are in a triangular prism shape, and one rectangular surface is connected with the lower surface of the vibrating body. The shape design of the crawling teeth can enable the crawling teeth 3 to be in linear line contact with the pipeline, so that the force of the crawling teeth 3 on the pipeline is increased, the two sides of the crawling teeth 3 are in linear design to facilitate climbing of rectangular pipelines with different pipe diameters or other polygonal pipelines, and the crawling teeth 3 are in arc edge structures similar to crescent shapes in the middle of edges in ground contact, so that climbing of circular pipelines with different pipe diameters is facilitated. Specifically, the length of the arc blade structure in the middle of the crawling tooth is set to be 8mm, and the straight line structures at two sides except the middle arc structure can be in contact with the pipeline, as shown in fig. 2, so that if the width of the square pipeline is greater than 8mm, the square pipeline can have good line contact according to old people, and a good climbing effect can be achieved. It should be specifically noted that the length of the arc blade structure in the present invention can be set in a customized manner according to the actual situation.
The position of the crawling teeth 3 is determined by the driving principle of an ultrasonic actuator, so that the crawling teeth 3 can meet the requirement of different movement directions in different vibration modes. The distance is set for to the interval between the tooth 3 of crawling, sets up two teeth 3 of crawling in this embodiment, through applying excitation voltage to piezoceramics piece 2, excitation vibration body 1 vibrates, further drives the tooth 3 of crawling to the ground motion, realizes the climbing process of robot. It should be specifically noted that the ground movement in the present invention refers to the movement of the robot on the ground, the pipeline, and other scenes.
When excitation voltages of the same amplitude and the same frequency are applied to the piezoelectric ceramic plates on the upper side of the vibrator 1, respectively (the excitation signals are sinusoidal signals), longitudinal vibrations are excited on the vibrator 1. When the phases of the two excitation signals are 180 degrees different from each other, the front side piezoelectric ceramic plate lengthens in the length direction, the rear side piezoelectric ceramic plate lengthens in the length direction under the excitation of the front side piezoelectric ceramic plate and the rear side piezoelectric ceramic plate, the vibration body 1 is promoted to complete second-order bending vibration, the vibration mode is shown in fig. 4, and meanwhile the crawling teeth 3 are driven to move oppositely, so that the actuator moves backwards, as shown by lines a and b in fig. 3. When the phase difference is 0 degrees, the piezoelectric ceramic plates 2 on the front side and the rear side act identically, the vibration body 1 is promoted to complete three-order bending vibration, the vibration mode is shown in fig. 5, and meanwhile, the crawling teeth 3 are driven to move to the ground, so that the actuator moves forwards, bidirectional movement is realized, and the characteristic of the climbing movement of a squirrel is completed, as shown by c and d lines in fig. 3.
The small pipe climbing robot is designed in the smallest possible size in this embodiment as a target, and the requirements of the electrical signal cannot be made too high. The realization frequency of the second-third-order bending vibration mode is related to the overall size of the transducer unit, and the length of the vibrator when the maximum driving force to weight ratio is selected by test is 60mm. The corresponding electrical signals are then most suitably adjusted to a thickness of 3mm, and the drive frequencies are determined to be 19kHz and 37kHz. Furthermore, the piezoelectric ceramics are selected to meet the requirement of amplifying the displacement of the vibrator to the greatest extent, so that the selected piezoelectric ceramics are attached to the wave crest and the wave trough generated by vibration, and the size is adjusted and set in a self-defining way according to the requirement. The distance between the two patches is required to be determined according to the wave crest and the wave trough of the second-third-order bending vibration mode of the vibrator, and the position generated by the wave crest and the wave trough is related to the size of the vibrator, so that the patches can be adjusted and set in a self-defining mode according to the size of the vibrator.
The specification of the crawling tooth has small relation with the mode of realizing second-third-order bending vibration, the crawling tooth serves as an output point of displacement and force in the invention, the size is small, the influence on vibration of the vibrator is small, and therefore the size can be adjusted and set in a self-defined mode as required.
The piezoelectric transducer unit is excited by frequency conversion phase modulation in the mode of same-mode variable-order actuation, the driving and configuration are simple, the manufacturing and assembly errors are reduced, and the integration of a multi-application scene system is easy to realize.
The transducer unit further comprises a mounting roller 4, the mounting roller 4 comprising a front side roller and a rear side roller, mounted at the front end and the rear end of the vibrator, respectively, the mounting roller 4 being adapted to fix the gripping mechanism. As shown in fig. 6, the clamping mechanism includes an upper fixed bearing plate 7 and a lower fixed bearing plate 7, wherein the two fixed bearing plates 7 are respectively provided with a transducer unit through a mounting roller 4, the two fixed bearing plates are connected through a screw 8, the screw 8 is fixed by a spring 9 and a nut 10, in this embodiment, the screw is a force application screw, the spring is a longitudinal coil spring, and the nut is a force application nut.
Specifically, in this embodiment, a pair of transducer units are encircling to form a bionic micro pipe climbing robot based on squirrel motions, two transducer units are connected to a fixed bearing plate 7 through a transducer unit installation roller 4, then are connected to upper and lower fixed bearing plates 7 through a force application screw, a longitudinal coil spring is connected in series between the upper fixed bearing plate 7 and the force application nut, and foot surfaces of the two transducer units face each other. When the force application nut is screwed, the longitudinal spiral spring is extruded, downward pressure is generated on the upper energy converter unit 5, and meanwhile, a reaction force is also generated on the force application nut, the reaction force indirectly acts on the force application screw, and the force application screw generates upward pressure on the lower energy converter unit 6, so that the pipeline is clamped against the influence of self gravity. By controlling the frequency and phase of the excitation signals of the upper transducer unit 5 and the lower transducer unit 6, the bidirectional movement of the micro tube climbing robot can be realized.
In this embodiment, after the clamping mechanism is added, in order to make the micro climbing robot move upwards, the upper transducer unit 5 and the lower transducer unit 6 are excited by piezoelectric ceramics to work in a third-order bending vibration mode, the phases of the four piezoelectric ceramics are the same, and the frequencies are the same, if the micro climbing robot moves downwards, the upper transducer unit 5 and the lower transducer unit 6 are excited by piezoelectric ceramics to work in a second-order bending vibration mode, the phases of the two piezoelectric ceramics of the same transducer unit are mutually different by 180 degrees, the frequencies are the same, and the phases and the frequencies of piezoelectric ceramics at the same positions between the two transducer units are the same.
According to the invention, by designing the crescent notch crawling teeth and the elastic clamping structure, the adaptability of the outer pipeline climbing robot square tube/round tube in different shapes and with different sizes of pipe diameter pipelines is improved.
The miniature pipe climbing piezoelectric robot based on the squirrel bionic motion mechanism designed by the embodiment can keep motion performance basically unchanged under environments with different pipe diameters and different pipe types, can achieve the motion speed of 0.18m/s and the high load ratio of 5.6 times under the condition that an excitation signal is low voltage 30V, realizes breakthrough of the miniature pipe climbing piezoelectric robot in performance, and reveals application prospects of the miniature pipe climbing piezoelectric robot in various industrial environments.
Embodiment two:
The second embodiment of the present invention provides a driving method for the outer pipeline climbing robot driven by piezoelectricity in the first embodiment, comprising the following steps:
And step 1, applying excitation voltage with the same amplitude and the same frequency to the piezoelectric ceramic plate to excite the vibration body to vibrate.
And 2, adjusting the phase difference of excitation voltages between the piezoelectric ceramic plates according to task requirements to enable the vibrating body to drive the crawling teeth to move to the ground.
And 3, after the use is completed, turning off the excitation voltage and resetting the transducer unit.
In the step 2, when the phases of the two excitation signals are 180 degrees different, the front piezoelectric ceramic plate is elongated in the length direction, the rear piezoelectric ceramic plate is shortened in the length direction, when the front piezoelectric ceramic plate is shortened in the length direction, the rear piezoelectric ceramic plate is elongated in the length direction, and under the excitation of the two piezoelectric ceramic plates, the vibration body is promoted to complete second-order bending vibration, and meanwhile the crawling teeth are driven to move to the ground, so that the transducer unit moves backwards.
When the phase difference is 0 degree, the piezoelectric ceramic plates at the front side and the rear side act identically, so that the vibration body is promoted to complete three-order bending vibration, and meanwhile, the crawling teeth are driven to move to the ground, so that the transducer unit moves forwards.
The steps involved in the second embodiment correspond to those of the first embodiment, and reference is made to the relevant description of the first embodiment for the implementation manner.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.