Variable-gage link control method and system for a tunnel crawling robot

Abstract

The application provides a variable-diameter connecting rod control method and system for a channel crawling robot, and relates to the field of special robots, and comprises the following steps: controlling a variable-diameter connecting rod mechanism to open, and acquiring rotation angle data of a connecting rod hinge in the variable-diameter connecting rod mechanism in real time, and acquiring pressure data of a pressure receiving part in the variable-diameter connecting rod mechanism in real time; determining whether the rotation angle reaches an expected angle according to the rotation angle data, acquiring a reasonable pressure range corresponding to the expected angle after the expected angle is reached, determining a fine adjustment strategy according to a comparison result of the pressure data and the reasonable pressure range, and executing the fine adjustment strategy until the pressure data meets the reasonable pressure range; after the fine adjustment strategy is executed, the variable-diameter connecting rod mechanism is controlled to continue to open, and when it is detected that the pressure data sharply increases and the rotation angle data does not change, it is determined that the variable-diameter is completed. The reliability of variable-diameter completion determination is significantly improved, the problems of unstable support or excessive driving caused by inaccurate determination are solved, the work efficiency is improved, and the error is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of special robots, in particular, to a variable-diameter connecting rod control method and system for a channel crawling robot. BACKGROUND

[0002] In the development process of modern industrial automation and complex mechanical systems, the precise control of mechanical structures is increasingly critical. As an important component of many mechanical structures, variable-diameter connecting rods are widely used in various scenarios. For example, in the field of industrial channel detection robots, channel detection robots need to enter the interior of channels of different diameters to perform detection work. To adapt to the change of the channel diameter, a screw-nut pair is often used to drive a parallel connecting rod mechanism to realize variable-diameter function, so as to ensure that the robot can stably travel in the channel and carry out detection work. In the chopping device of large agricultural harvesting machinery, to meet the chopping needs of different crops, the diameter of the roller is adjusted by the variable-diameter connecting rod to realize efficient chopping of different thicknesses of crop stems. In construction equipment, some telescopic support structures also use variable-diameter connecting rods to flexibly adjust the support radius according to different support scenarios, ensuring the stable operation of the equipment. However, the current variable-diameter connecting rod faces many challenges in practical application. On the one hand, in mechanical structures, the precise control of the opening radius and support pressure of the variable-diameter connecting rod directly affects the working performance and stability of the entire mechanical structure. For example, in channel detection robots, if the variable-diameter connecting rod cannot accurately adjust the opening radius, it may cause the robot to be blocked in the channel and fail to complete the detection task; in agricultural harvesting machinery, improper control of the support pressure of the variable-diameter connecting rod will result in uneven quality of chopped feed, affecting the nutritional value of the feed. On the other hand, with the advancement of industrial upgrading and the concept of intelligent manufacturing, the automation and intelligentization of mechanical structures are increasingly required, and traditional variable-diameter connecting rod control technology has been difficult to meet the current needs of high-precision and intelligent control.

[0003] In the process of implementing the present application, the applicant found that in the field of special robots, robots for crawling in channels mostly have variable-diameter walking mechanisms, but their variable-diameter implementation mainly relies on motor running time control or mechanical limit switch triggering, lacking precise judgment of the actual working state. For example, only by presetting the motor rotation time to control the opening degree of the connecting rod, the actual opening state is easy to deviate from the expected state due to factors such as roughness of the channel wall and mechanical wear of the connecting rod; mechanical limit switches have the problems of response lag and easy vibration-induced false triggering. Therefore, how to accurately control the variable-diameter of the walking mechanism of the channel crawling robot has become a technical problem to be solved. SUMMARY

[0004] The application aims to at least solve one of the technical problems in the prior art or related art, and discloses a variable-diameter connecting rod control method and system for a channel crawling robot, which improves the variable-diameter connecting rod control accuracy of the channel crawling robot, especially improves the reliability of variable-diameter completion determination, and further guarantees the safety and stability of the robot when performing a task.

[0005] The first aspect of the application discloses a variable-diameter connecting rod control method for a channel crawling robot, which comprises the following steps: sending a start signal to a driving motor of a variable-diameter connecting rod mechanism to drive the variable-diameter connecting rod mechanism to start opening, and acquiring rotation angle data of a connecting rod hinge in the variable-diameter connecting rod mechanism and pressure data of a pressure receiving part in the variable-diameter connecting rod mechanism in real time; determining whether the rotation angle reaches an expected angle according to the rotation angle data; after the expected angle is reached, acquiring a reasonable pressure range corresponding to the expected angle, determining a fine-tuning strategy according to a comparison result of the pressure data and the reasonable pressure range, and executing the fine-tuning strategy until the pressure data meets the reasonable pressure range; the fine-tuning strategy comprises: controlling the driving motor to rotate forward or controlling the driving motor to rotate reversely; and after the fine-tuning strategy is executed, the variable-diameter connecting rod mechanism continues to open, and when it is detected that the pressure data sharply increases and the rotation angle data does not change, it is determined that the variable-diameter is completed.

[0006] According to the variable-diameter connecting rod control method for the channel crawling robot, preferably, the method further comprises the following steps: simulating various pipeline environments by building an experimental platform, recording the rotation angle data and the pressure data of the variable-diameter connecting rod mechanism when the variable-diameter connecting rod mechanism reaches a stable state under various channel diameters, and establishing a data model of the corresponding relationship between the rotation angle data and the pressure data, so as to acquire the reasonable pressure range corresponding to the expected angle from the data model.

[0007] According to the variable-diameter connecting rod control method for the channel crawling robot, preferably, the method further comprises the following step: after the variable-diameter is completed, determining the elongation of the variable-diameter connecting rod mechanism according to the rotation angle data and the length of the connecting rod.

[0008] According to the variable-diameter connecting rod control method for the channel crawling robot, preferably, the step of determining whether the rotation angle reaches the expected angle according to the rotation angle data specifically comprises the following steps: setting the expected angle according to the channel diameter; in the process of opening the variable-diameter connecting rod mechanism, the rotation angle data is detected and compared with the expected angle in real time, if the deviation is greater than 1°, the variable-diameter connecting rod mechanism continues to open, and the detection is restarted after pausing for 100 ms for every 0.5° adjustment until the deviation is less than or equal to 0.5°.

[0009] According to the variable-diameter connecting rod control method for the channel crawling robot, preferably, the variable-diameter connecting rod mechanism specifically comprises:

[0010] The four-bar linkage is composed of two long connecting rods and two short connecting rods, the lower long connecting rod is hinged to the robot body, and the upper long connecting rod is hinged to the bottom of the walking unit;

[0011] The connecting rod is hinged at one end to the middle hinge point of the four-bar linkage and is used for connecting the walking unit at the other end;

[0012] The bottom of the walking unit is hinged to the upper long connecting rod of the four-bar linkage and the connecting rod;

[0013] The variable-diameter rod is hinged at one end to the robot body and at the other end to the middle hinge point of the four-bar linkage, and is used for driving the four-bar linkage to expand or contract;

[0014] The screw rod assembly is fixed on the robot body, and the nut is connected to the support rod;

[0015] The support rod is connected at one end to the nut and at the other end to the middle part of the variable-diameter rod, and is used for supporting and pushing the variable-diameter rod;

[0016] The driving motor is connected to the screw rod assembly and is used for driving the screw rod assembly.

[0017] According to the variable-diameter connecting rod control method for the channel crawling robot disclosed in the present application, preferably, the hinge point of the connecting rod is the hinge point of the lower long connecting rod of the four-bar linkage and the robot body, and the pressure point is the connection point of the support rod and the nut.

[0018] According to the variable-diameter connecting rod control method for the channel crawling robot disclosed in the present application, preferably, the pressure data surge and the rotation angle data remain unchanged, and specifically includes: detecting the pressure value increase amplitude > 20N / s and the angle change amount < 0.1° for multiple times continuously at intervals of 100ms.

[0019] The second aspect of the present application discloses a variable-diameter connecting rod control system for a channel crawling robot, comprising: a memory for storing program instructions; a processor for calling the program instructions stored in the memory to realize the variable-diameter connecting rod control method for the channel crawling robot according to any of the above technical solutions.

[0020] Compared with the prior art, the beneficial effects of the present application at least include: establishing a "pressure-angle" two-dimensional real-time feedback mechanism to accurately control the elongation of the variable-diameter connecting rod (which can still operate stably under abnormal conditions such as loose wear of the connecting rod), solving the problems of unstable support or excessive driving, and ensuring that the robot's telescopic foot can be stably supported on the inner wall of the channel, thereby ensuring walking stability; the dual-determination logic of "pressure surge + angle stability" can accurately capture the moment when the connecting rod mechanism is in rigid contact with the inner wall of the channel: the pressure surge reflects that the connecting rod has borne effective support force, and the angle stability proves that the mechanical structure is no longer deformed, and the combination of the two ensures the accuracy of the determination of the variable-diameter completion from the two dimensions of force and motion. By establishing a data model, the accuracy of pressure determination is improved, and the rotation angle of the connecting rod is dynamically adjusted to realize the cooperative optimization of pressure and angle. Without adding additional detection devices, the elongation of the variable-diameter connecting rod mechanism can be automatically calculated through the length of the connecting rod and the rotation angle of the connecting rod, thereby determining the pose of the robot. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A flowchart of a variable-diameter connecting rod control method for a channel crawling robot according to an embodiment of the present application is shown.

[0022] Figure 2 A structural schematic diagram of a variable-diameter connecting rod mechanism according to an embodiment of the present application is shown.

[0023] Figure 3 A robot working state schematic diagram according to an embodiment of the present application is shown.

[0024] Figure 4 A schematic block diagram of a variable-diameter connecting rod control system for a channel crawling robot according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0025] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the present application, however, the present application can also be implemented in other ways different from those described herein, and therefore, the present application is not limited to the specific embodiments disclosed below.

[0026] As Figure 1 shown, according to an embodiment of the present application, a variable-diameter connecting rod control method for a channel crawling robot is disclosed, comprising:

[0027] Step one: send a start signal to the driving motor of the variable-diameter connecting rod mechanism to drive the variable-diameter connecting rod mechanism to start to open, and real-time acquire the rotation angle data of the connecting rod hinge in the variable-diameter connecting rod mechanism, and real-time acquire the pressure data of the pressure receiving part in the variable-diameter connecting rod mechanism;

[0028] Step two: determine whether the rotation angle reaches the expected angle according to the rotation angle data;

[0029] Step three: after reaching the expected angle, obtain the reasonable pressure range corresponding to the expected angle, determine the fine-tuning strategy according to the comparison result of the pressure data and the reasonable pressure range, and execute the fine-tuning strategy until the pressure data meets the reasonable pressure range; wherein the fine-tuning strategy includes: controlling the driving motor to rotate forward or controlling the driving motor to rotate reverse;

[0030] Step four: after executing the fine-tuning strategy, control the variable-diameter connecting rod mechanism to continue to open, and when it is detected that the pressure data increases sharply and the rotation angle data does not change, it is determined that the variable-diameter is completed.

[0031] According to the above embodiment, preferably, further comprising: simulating multiple pipeline environments by building an experimental platform, recording the rotation angle data and pressure data of the variable-diameter connecting rod mechanism when it reaches a stable state under multiple channel diameters, and establishing a data model of the corresponding relationship between the rotation angle data and the pressure data, so as to obtain the reasonable pressure range corresponding to the expected angle from the data model. For example, a simulated channel test platform (pipe diameter 50-200mm) is built in the laboratory, 100 variable-diameter experiments are performed every 5mm pipe diameter, the angle (0-90°), pressure (0-100N) and connecting rod stable state (whether to slip is determined by high-speed photography) are recorded. Linear regression analysis is performed on 10000 groups of data using MATLAB, and the angle-pressure fitting formula P=0.5θ+25 (R²=0.92) is obtained, and the reasonable pressure range is determined as [P-5, P+5] according to the 95% confidence interval, wherein P represents pressure and θ represents rotation angle. In addition, the linear regression model can be replaced by a BP neural network model, and the network is trained by 10000 experimental data (input angle, output pressure range), and the fitting accuracy is higher (R² is improved to 0.96) in a nonlinear scene (such as elastic deformation of the connecting rod).

[0032] According to the above embodiment, preferably, further comprising: after completing the variable-diameter, determining the elongation of the variable-diameter connecting rod mechanism according to the rotation angle data and the connecting rod length.

[0033] According to the above embodiment, preferably, step two specifically includes: setting the expected angle according to the channel diameter; during the opening of the variable-diameter connecting rod mechanism, the rotation angle data is detected and compared with the expected angle in real time, if the deviation is greater than 1°, the variable-diameter connecting rod mechanism is controlled to continue to open, and it is paused for 100ms to re-detect every 0.5° adjustment until the deviation is less than or equal to 0.5°.

[0034] According to the above embodiment, preferably, the pressure data surge and the rotation angle data remain unchanged, specifically including: detecting the pressure value increase > 20N / s and the angle change < 0.1° for multiple times continuously at an interval of 100ms.

[0035] As shown in Figure 2 and Figure 3 According to another embodiment of the application, the specific structure of the variable-diameter connecting rod mechanism of the above embodiment is also disclosed, which specifically includes:

[0036] The four connecting rods are composed of two long connecting rods 1 and two short connecting rods 2, the lower long connecting rod is hinged to the robot body 9, and the upper long connecting rod is hinged to the bottom of the walking unit;

[0037] The connecting rod 3 is hinged at one end to the middle hinge point of the four connecting rods and is used for connecting the walking unit at the other end;

[0038] The walking unit 4 is hinged at the bottom to the upper long connecting rod of the four connecting rods and the connecting rod;

[0039] The variable-diameter rod 5 is hinged at one end to the robot body and at the other end to the middle hinge point of the four connecting rods, and is used for driving the four connecting rods to expand or contract;

[0040] The screw assembly 6 is fixed on the robot body, and the nut is connected to the support rod;

[0041] The support rod 7 is connected to the nut at one end and is hinged to the middle of the variable-diameter rod at the other end, and is used for supporting and pushing the variable-diameter rod;

[0042] The driving motor 8 is connected to the screw assembly and is used for driving the screw assembly.

[0043] In this embodiment, the lower long connecting rod of the four connecting rods is provided with an angle sensor 10 at the hinge with the robot body, and the support rod is provided with a pressure sensor 11 at the connection with the nut. Figure 3 The working state of the three-legged channel crawling robot is shown, and the robot system has three variable-diameter connecting rod mechanisms, each of which has the same hardware structure and the same control logic. The control method of the driving motor includes: controlling the motor by electromagnetic signal width modulation (PWM) method, the electromagnetic signal frequency determines the motor speed (500-5000Hz corresponds to 50-500rpm), and the electromagnetic signal direction signal controls the motor forward and reverse rotation (forward rotation expands the connecting rod, and reverse rotation contracts the connecting rod).

[0044] According to another embodiment of the application, the working process of the industrial channel detection robot (channel crawling robot) in the actual working scene is also disclosed:

[0045] Initialization stage: before entering the channel, the connecting rod is in a closed state (0° angle), and the control unit sends an initial electromagnetic signal (1000 electromagnetic signals, corresponding to 0.5 turns), to drive the motor to drive the connecting rod to start to open.

[0046] Angle adjustment process: the angle sensor feeds back the angle in real time, and when 30° is detected (corresponding to a radius of about 70 mm, which is less than the required 80 mm radius of the 150 mm channel), the control unit continuously outputs the electromagnetic signal, and the angle is increased by 5° every 200 ms, until the angle reaches 65° (at this time, the calculated radius is 78 mm).

[0047] Pressure coordination determination: when the angle is 65°, the pressure sensor detects a value of 28N, and the data model returns a reasonable pressure range of 32.5-42.5N corresponding to 65°. The control unit determines that the pressure is low, and continues to drive the motor to increase the angle to 68°, and the pressure rises to 35N (into the reasonable range).

[0048] Variable radius completion determination: when the connecting rod contacts the inner wall of the channel, the pressure value increases from 35N to 50N within 0.3 seconds, and the angle remains unchanged at 68° (no change for three consecutive detections), and the control unit determines that the variable radius is completed, and the angle is locked at 68°.

[0049] Radius calculation: according to the geometric formula R=L×sinθ (L is the length of the connecting rod 120 mm, and θ is 68°), the final opening radius is calculated as 120×sin68°≈111mm (matching the inner wall radius 75mm of the 150mm channel + the robot body radius 36mm), and the data is stored in the PLC internal register.

[0050] As Figure 4 shown, according to another embodiment of the application, a variable radius connecting rod control system 400 for a channel crawling robot is also disclosed, comprising: a memory 401 for storing program instructions; a processor 402 for calling the program instructions stored in the memory to realize the variable radius connecting rod control method for the channel crawling robot as described above.

[0051] To sum up, the above-mentioned embodiments of the present application solve the problems of low efficiency and easy error in the prior art, improve work efficiency and reduce errors. Specifically: by detecting the angle of the variable-diameter connecting rod rotating joint and the pressure at the pressure receiving part, a "pressure-angle" two-dimensional real-time feedback mechanism is formed, and accurate monitoring and adjustment of the variable-diameter process are realized. The variable-diameter completion is determined based on the "pressure surge and angle stability" determination logic, which ensures stable contact between the variable-diameter system and the inner wall of the channel. By establishing a pressure range model and calling the model data to determine whether the current pressure is within a reasonable range, the angle is dynamically adjusted to realize the coordinated optimization of pressure and angle. According to the angle data after the variable-diameter is completed, the opening radius is automatically calculated, and the posture of the variable-diameter connecting rod system can be grasped without additional measuring equipment.

[0052] All or part of the steps in the various methods of the above-mentioned embodiments can be completed by a program controlling the relevant hardware, which can be stored in a readable storage medium, including Read-Only Memory (ROM), Random Access Memory (RAM), Programmable Read-only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), One-time Programmable Read-Only Memory (OTPROM), Electrically-Erasable Programmable Read-Only Memory (EEPROM), Compact Disc Read-Only Memory (CD-ROM) or other optical disk storage, magnetic disk storage, magnetic tape storage, or any other readable medium capable of carrying or storing data.

[0053] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A variable-diameter linkage control method for a channel crawling robot, characterized in that, include: A start signal is sent to the drive motor of the variable diameter linkage mechanism to drive the mechanism to open, and the rotation angle data at the hinge points of the linkages is acquired in real time, as well as the pressure data at the pressure points. The variable diameter linkage mechanism specifically includes: a four-bar linkage, consisting of two long and two short links, with the lower long link hinged to the robot body and the upper long link hinged to the bottom of the walking unit; and a connecting rod, one end of which is hinged to the middle hinge point of the four-bar linkage, and the other end used to connect to the walking unit. The system comprises: a walking unit; a walking unit, the bottom of which is hinged to the upper long connecting rod of the four-bar linkage and the connecting rod; a variable diameter rod, one end of which is hinged to the robot body and the other end of which is hinged to the middle hinge point of the four-bar linkage, used to drive the four-bar linkage to open or retract; a lead screw assembly, fixed to the robot body, with a lead screw nut connected to a support rod; a support rod, one end of which is connected to the lead screw nut and the other end of which is hinged to the middle of the variable diameter rod, used to support and push the variable diameter rod; and a drive motor, connected to the lead screw assembly, used to drive the lead screw assembly. Determine whether the rotation angle has reached the expected angle based on the rotation angle data; After reaching the expected angle, the reasonable pressure range corresponding to the expected angle is obtained. A fine-tuning strategy is determined based on the comparison between the pressure data and the reasonable pressure range. The fine-tuning strategy is executed until the pressure data meets the reasonable pressure range. The fine-tuning strategy includes: controlling the drive motor to rotate forward or controlling the drive motor to rotate in reverse. After executing the fine-tuning strategy, the variable diameter linkage mechanism is controlled to continue opening. When a surge in pressure data is detected while the rotation angle data remains unchanged, the variable diameter is determined to be complete.

2. The variable-diameter linkage control method for a crawling robot according to claim 1, characterized in that, Also includes: By building an experimental platform to simulate various pipeline environments, the rotation angle data and pressure data of the variable diameter linkage mechanism when it reaches a stable state under various channel diameters are recorded. A data model is established to establish the correspondence between the rotation angle data and the pressure data, so as to obtain the reasonable pressure range corresponding to the expected angle from the data model.

3. The variable-diameter linkage control method for a channel crawling robot according to claim 1, characterized in that, Also includes: After the diameter change is completed, the elongation of the diameter-changing linkage mechanism is determined based on the rotation angle data and the linkage length.

4. The variable-diameter linkage control method for a channel crawling robot according to claim 1, characterized in that, The step of determining whether the rotation angle has reached the expected angle based on the rotation angle data specifically includes: The expected angle is set according to the channel diameter; during the opening process of the variable diameter linkage mechanism, the rotation angle data is detected and compared with the expected angle in real time. If the deviation is greater than 1°, the variable diameter linkage mechanism is controlled to continue opening. The detection is paused for 100ms every time the adjustment is 0.5° until the deviation is less than or equal to 0.5°.

5. The variable-diameter linkage control method for a channel crawling robot according to claim 1, characterized in that, The hinge joint is the lower long link of the four-bar linkage that is hinged to the robot body, and the pressure point is the connection between the support rod and the nut.

6. The variable-diameter linkage control method for a channel crawling robot according to claim 1, characterized in that, The surge in pressure data while the rotation angle data remained unchanged specifically includes: At 100ms intervals, the increase in pressure data and the change in rotation angle data are detected simultaneously. If two adjacent detection results or two or more consecutive detection results show that the pressure increase is >20N / s and the angle change is <0.1°, then the system will detect the increase in pressure value.

7. A variable-diameter linkage control system for a channel crawling robot, characterized in that, include: Memory, used to store program instructions; A processor is configured to invoke the program instructions stored in the memory to implement the variable-diameter linkage control method for a channel crawling robot as described in any one of claims 1 to 6.

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