Pipeline robot posture stability control method and system

Abstract

The application provides a pipeline robot posture stability control method and system, and relates to the technical field of posture control. The application obtains speed data, curve data and the roll angle of each wheel of the robot in the pipeline curve, analyzes and determines the equivalent centrifugal force of each wheel of the pipeline robot, sets a limit roll angle, determines a safety margin, determines to execute a deceleration strategy or a compensation strategy according to the safety margin, determines the centrifugal force imbalance degree based on the equivalent centrifugal force, and further determines the centrifugal compensation torque. The comprehensive roll angle and the jitter compensation torque are obtained to apply the reverse compensation torque to each wheel by applying the torque to the wheel. The effect of the compensation strategy is verified, and the deceleration strategy is executed if the effect is unqualified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of posture control, in particular to a pipeline robot posture stability control method and system. BACKGROUND

[0002] With the increasing complexity and scale of urban underground pipe network systems, pipeline robots play an irreplaceable role in the inspection, cleaning and maintenance of pipelines for water supply, drainage, oil and gas transportation, etc. These robots can replace manual work to enter narrow, humid, toxic or dangerous environments with poor accessibility, perform high-definition video recording, leakage detection, pipe wall damage identification and other tasks, greatly improving the safety and intelligent level of municipal management and energy transportation. However, the inside of the pipeline is not an ideal straight path, and there are generally complex structures such as bends, tees and reducers. When the robot travels in the curved section, it will be subjected to the coupling effect of centrifugal force, gravity, pipe wall contact force and driving force, and is prone to posture instability, which manifests as body tilting, lateral shaking or even overall overturning. This instability not only leads to blurred images and distorted sensor data, but also may cause the robot to be stuck, fall or be damaged, directly threatening the continuity of the task and the safety of the equipment.

[0003] The existing technology mainly focuses on two types of methods: speed regulation and torque compensation. However, both methods have obvious limitations. The speed regulation method reduces the centrifugal force effect by reducing the travel speed, which is simple and reliable, but severely sacrifices the inspection efficiency and economic efficiency, making it difficult to meet the real-time requirements of large-scale, long-period pipeline detection. The torque compensation method generates an anti-overturning torque by applying a braking force or driving force to some wheels, but in the actual variable pipeline environment, due to the strong nonlinearity of the robot's dynamic response and the complexity of system jitter factors, the compensation strategy with fixed parameters often appears rigid, which may lead to control lag due to insufficient compensation or system oscillation due to excessive compensation, and cannot adapt to changes in different motion states throughout the journey.

[0004] The above information disclosed in the background section is only used to enhance the understanding of the background of the present disclosure, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] The purpose of the present application is to provide a pipeline robot posture stability control method and system to solve the problems raised in the background.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] A pipeline robot posture stability control method, the specific steps comprising:

[0008] Step 1: Obtain the speed data, curvature data of the bend and the roll angle of each wheel of the robot in the pipeline bend, and analyze to determine the equivalent centrifugal force at each wheel of the pipeline robot;

[0009] Step 2: Set a limit roll angle, determine a safety margin based on the limit roll angle and the roll angle, determine a control strategy according to the safety margin, the control strategy is a deceleration strategy or a compensation strategy, if the compensation strategy is adopted, proceed to step 3, if the deceleration strategy is adopted, proceed to step 5;

[0010] Step 3: Determine the centrifugal force imbalance based on the equivalent centrifugal force at all wheels, and further determine the centrifugal compensation torque; determine the comprehensive roll angle of the pipeline robot based on the roll angle of the wheel, obtain the jitter acceleration of the pipeline robot, determine the jitter compensation torque based on the jitter acceleration, determine the reverse compensation torque of each wheel based on the positional relationship between the wheel and the center of the bend, the centrifugal force imbalance, the centrifugal compensation torque, the comprehensive roll angle, the jitter acceleration and the jitter compensation torque, and apply the reverse compensation torque to each wheel by applying torque to the wheel;

[0011] Step 4: Measure the jitter acceleration of the pipeline robot after executing the compensation strategy, and compare it with the jitter acceleration before executing the compensation strategy, determine whether the compensation strategy is qualified according to the comparison result, if not, proceed to step 5;

[0012] Step 5: Set a deceleration step and a centrifugal iteration termination condition, decelerate the current speed by the deceleration step, if the centrifugal iteration termination condition is met, reduce the speed of the pipeline robot to the speed at the iteration termination; if the centrifugal iteration termination condition is not met within a preset number of iterations, halve the speed of the pipeline robot.

[0013] Further, the direction pointing to the center of the bend is called the inner side of the bend, and the direction opposite to the inner side of the bend is called the outer side of the bend; if the roll angle deviates to the outer side of the bend, the roll angle is set to a positive value, if the roll angle deviates to the inner side of the bend, the roll angle is set to a negative value, the comprehensive roll angle is the sum of all roll angles, if the comprehensive roll angle is positive, the comprehensive roll angle deviates to the outer side of the bend, if the comprehensive roll angle is negative, the comprehensive roll angle deviates to the inner side of the bend;

[0014] The formula for calculating the equivalent centrifugal force is:

[0015]

[0016] wherein, is the equivalent centrifugal force received by the i-th wheel of the pipeline robot, is the mass of the pipeline robot, is the speed of the pipeline robot, is the bend radius at the position of the pipeline robot; Let be the roll angle of the i-th wheel of the pipeline robot, where the roll angle of the wheel is the angle between the wheel and the vertically upward direction, and i is the index of the wheel.

[0017] Furthermore, the absolute values ​​of the roll angles of each wheel are compared to determine the absolute value of the maximum roll angle. The difference between the absolute value of the limit roll angle and the absolute value of the maximum roll angle is calculated. This difference is the safety margin. A safety margin threshold is preset. If the safety margin is less than the safety margin threshold, a deceleration strategy is used for control. If the safety margin is not less than the safety margin threshold, a compensation strategy is used for control.

[0018] Furthermore, based on the position of the wheels in the pipe, the wheels are divided into inner wheels and outer wheels. The wheels on the side of the pipe robot closer to the center of the pipe bend are called inner wheels, and the wheels on the side of the pipe robot farther away from the center of the pipe bend are called outer wheels.

[0019] The logic for calculating the centrifugal force imbalance is as follows: analyze the equivalent centrifugal force of all wheels to obtain the centrifugal force imbalance.

[0020] The formula for calculating the centrifugal force imbalance is:

[0021]

[0022] in, For the centrifugal force imbalance of the pipeline robot, Let be the weight of the i-th wheel of the pipeline robot. The total number of wheels, The equivalent centrifugal force on the i-th wheel of the pipeline robot is given by weighting the following criteria: if the wheel is the outer wheel, the weight is set to 1; if the wheel is the inner wheel, the weight is set to -1.

[0023] The jitter acceleration is the maximum jitter acceleration in the most recent control cycle;

[0024] The formula for calculating the jitter compensation torque is:

[0025]

[0026] For the vibration compensation torque of the pipeline robot, Let be the component of the pipe robot's jitter acceleration in the direction of the pipe robot's motion. The radius of the wheel;

[0027] The centrifugal compensation moment is a first centrifugal compensation moment or a second centrifugal compensation moment, and the second centrifugal compensation moment is greater than the first centrifugal compensation moment, a preset centrifugal imbalance threshold, if the centrifugal imbalance is less than the centrifugal imbalance, the first centrifugal compensation moment is used as the centrifugal compensation moment, if the centrifugal imbalance is not less than the centrifugal imbalance threshold, the second centrifugal compensation moment is used as the centrifugal compensation moment;

[0028] Further, if the comprehensive roll angle deviates to the outside of the curve, a reverse compensation moment of the sum of the centrifugal compensation moment and the jitter compensation moment is applied to the inner wheel, and a reverse compensation moment of the jitter compensation moment is applied to the outer wheel.

[0029] If the comprehensive roll angle deviates to the inside of the curve, a reverse compensation moment of the jitter compensation moment is applied to the inner wheel and the outer wheel.

[0030] Further, the jitter acceleration of the pipeline robot after the compensation strategy is executed is obtained, if the jitter acceleration of the pipeline robot is less than the jitter acceleration before the compensation strategy is executed, the compensation strategy is determined to be qualified, otherwise, the compensation strategy is determined to be unqualified.

[0031] Further, the deceleration strategy specifically comprises: setting a deceleration step, decelerating the current speed according to the deceleration step, and calculating the equivalent centrifugal force and the centrifugal imbalance, iterating, if the centrifugal iteration termination condition is met, the speed of the pipeline robot is reduced to the speed at the iteration termination; if the centrifugal iteration termination condition is not met within a preset iteration number, the speed of the pipeline robot is halved.

[0032] The centrifugal iteration termination condition is that the centrifugal force is less than a preset centrifugal force threshold, and the centrifugal imbalance is less than a centrifugal imbalance threshold.

[0033] The application further provides a pipeline robot posture stability control system, which is used for the pipeline robot posture stability control method and specifically comprises:

[0034] A centrifugal analysis module is configured to obtain speed data of the robot in the pipeline curve, curve curvature data, and roll angle of each wheel, and analyze and determine the equivalent centrifugal force of each wheel of the pipeline robot.

[0035] A strategy selection module is configured to set a limit roll angle, determine a safety margin based on the limit roll angle and the roll angle, determine a control strategy according to the safety margin, the control strategy is a deceleration strategy or a compensation strategy, if the compensation strategy is adopted, step 3 is performed, if the deceleration strategy is adopted, step 5 is performed.

[0036] The strategy compensation module is used for determining a centrifugal imbalance degree based on equivalent centrifugal forces at all wheels, and then determining a centrifugal compensation torque; determining a comprehensive roll angle of the pipeline robot based on a roll angle of the wheel, obtaining a jitter acceleration of the pipeline robot, determining a jitter compensation torque based on the jitter acceleration, determining a reverse compensation torque of each wheel based on a positional relationship between the wheel and the center of the curve, the centrifugal imbalance degree, the centrifugal compensation torque, the comprehensive roll angle, the jitter acceleration and the jitter compensation torque, and applying the reverse compensation torque to each wheel by applying a torque to the wheel;

[0037] The compensation evaluation module is used for measuring the jitter acceleration of the pipeline robot after the compensation strategy is executed, and comparing the jitter acceleration with the jitter acceleration before the compensation strategy is executed, judging whether the compensation strategy is qualified according to a comparison result, and entering step 5 if the compensation strategy is not qualified.

[0038] The strategy deceleration module is used for setting a deceleration step and a centrifugal iteration termination condition, decelerating iteration of a current speed according to the deceleration step, reducing the speed of the pipeline robot to the speed at the iteration termination if the centrifugal iteration termination condition is met, and halving the speed of the pipeline robot if the centrifugal iteration termination condition is not met within a preset iteration number.

[0039] Compared with the prior art, the present application has the following beneficial effects:

[0040] The present application introduces a key criterion of "safety margin" to construct a dual-mode controller. When the attitude risk is low (sufficient safety margin), the system preferentially adopts the torque compensation mode to actively offset the unbalanced torque through accurate motor torque distribution, thereby maintaining stability without speed reduction and ensuring the inspection efficiency. When the attitude risk is high (insufficient safety margin), the system intelligently switches to the deceleration mode to eliminate the risk by quickly reducing the speed, which is the most reliable way.

[0041] The compensation strategy of the present application is not single and fixed. It quantifies the instability degree by "centrifugal imbalance degree" and accordingly calls different compensation torques in different levels (first, second), realizing the fine control of "small deviation fine tuning and large deviation strong intervention". At the same time, the "jitter compensation torque" is introduced to include the influence of the robot's own vibration into the compensation system, making the control model more close to the actual complex working conditions.

[0042] The present application does not end after executing the compensation in an "open loop" manner, but adds a key "post-compensation evaluation" link. The control effect is verified by comparing the jitter accelerations before and after the compensation, and the deceleration strategy is switched if the compensation is not qualified. This closed-loop design enables the system to have the ability of "self-verification and error correction", preventing the system from being in a loss of control state when the compensation strategy is not effective, thereby greatly enhancing the reliability and safety of the system. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The whole method flowchart of the present application is shown.

[0044] Figure 2 The whole system structure diagram of the present application is shown. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with specific examples.

[0046] It should be noted that, unless otherwise defined, technical terms or scientific terms used in the present application should be understood as the common meanings understood by those skilled in the art to which the present application belongs. The terms "first", "second" and similar terms used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, without excluding other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "up", "down", "left", "right" and the like only represent relative positional relationships, which can change accordingly when the absolute positions of the described objects change.

[0047] Embodiment:

[0048] Please refer to Figure 1 The present application provides a technical solution:

[0049] A pipeline robot posture stability control method, the specific steps comprising:

[0050] Step 1: Obtain the speed data of the robot in the pipeline curve, the curve curvature data and the roll angle of each wheel, and analyze and determine the equivalent centrifugal force at each wheel of the pipeline robot;

[0051] Further, the direction pointing to the center of the curve is called the inner side of the curve, and the direction opposite to the inner side of the curve is called the outer side of the curve; if the roll angle deviates to the outer side of the curve, the roll angle is set to a positive value, if the roll angle deviates to the inner side of the curve, the roll angle is set to a negative value, the comprehensive roll angle is the sum of all roll angles, if the comprehensive roll angle is positive, the comprehensive roll angle deviates to the outer side of the curve, if the comprehensive roll angle is negative, the comprehensive roll angle deviates to the inner side of the curve;

[0052] The formula for calculating the equivalent centrifugal force is:

[0053]

[0054] wherein, is the equivalent centrifugal force experienced by the i-th wheel of the pipe robot, is the mass of the pipe robot, is the speed of the pipe robot, is the curvature radius of the bend where the pipe robot is located; is the roll angle of the i-th wheel of the pipe robot, the roll angle of the wheel being the angle between the wheel and the vertical upward direction, i being the index of the wheel.

[0055] is the centrifugal force experienced by the pipe robot when passing through the bend, as the pipe is circular and the environment inside the pipe is complex, the pipe robot is likely to not travel horizontally forward, at this time the wheel is not vertical upward, the angle between the pipe robot and the vertical upward direction, i.e. the roll angle of the wheel; the centrifugal force is orthogonally decomposed, wherein the equivalent centrifugal force component in the plane of the wheel is offset by the weight of the pipe robot and will not affect the attitude of the pipe robot, and the equivalent centrifugal force component perpendicular to the plane of the wheel directly affects the attitude balance of the pipe robot when passing through the bend, analysis of the equivalent centrifugal force can further obtain the influence of the equivalent centrifugal force on different wheels, providing an important theoretical basis for later compensation control.

[0056] Step 2: setting a limit roll angle, and determining a safety margin based on the limit roll angle and the roll angle, determining a control strategy according to the safety margin, the control strategy being a deceleration strategy or a compensation strategy, if the compensation strategy is adopted, step 3 is performed, if the deceleration strategy is adopted, step 5 is performed;

[0057] The limit roll angle can be determined by inviting experts in the field to analyze and demonstrate based on the actual size and shape of the pipe and the pipe robot, and then giving the maximum roll angle of the wheel without affecting the normal driving of the pipe robot as the limit roll angle. Based on the structural parameters and operating environment of the pipe robot, the attitude stability boundary of the pipe robot at different speeds and bend curvatures is determined through dynamic simulation, the angle of multiple pipe robot rollovers is simulated, the average value is taken as 90%, to determine the limit roll angle, and the safety margin threshold is set to 20%-30% of the limit roll angle, which not only reserves sufficient response margin for the control system, but also avoids frequent triggering of the deceleration strategy due to too conservative threshold setting. This is prior art and will not be described here.

[0058] Further, the logic of obtaining the safety margin is: comparing the absolute values of the roll angles of the wheels to determine the maximum absolute value of the roll angle, calculating the difference between the limit roll angle and the maximum absolute value of the roll angle, and the difference is the safety margin. A safety margin threshold is preset. If the safety margin is less than the safety margin threshold, it means that the pipeline robot is in an unstable state. Immediate and stable control means are used to avoid the pipeline robot from rolling over and other direct causes of pipeline robot operation termination instability accidents, i.e., directly using a deceleration strategy for control. If the safety margin is not less than the safety margin threshold, it means that the posture of the pipeline robot is relatively far from the limit, and there is a relatively large control margin. A fine-tuning method can be used to slowly compensate for the posture stability of the pipeline robot, i.e., using a compensation strategy for control. The present application divides the pipeline robot into relatively unstable and relatively stable postures through the safety margin, and uses different control strategies for different situations. The appropriate control strategy can be used for the actual motion of the pipeline robot to achieve the posture stability control that meets the actual situation of the pipeline robot.

[0059] Step 3: determining the centrifugal force imbalance degree based on the equivalent centrifugal forces at all wheels, and further determining the centrifugal compensation torque; determining the comprehensive roll angle of the pipeline robot based on the roll angles of the wheels, obtaining the shaking acceleration of the pipeline robot, determining the shaking compensation torque based on the shaking acceleration, and determining the reverse compensation torque of each wheel based on the positional relationship between the wheels and the center of the curve, the centrifugal force imbalance degree, the centrifugal compensation torque, the comprehensive roll angle, the shaking acceleration and the shaking compensation torque, and applying the reverse compensation torque to each wheel by applying torque to the wheels;

[0060] Further, the wheels are divided into inner wheels and outer wheels based on the positions of the wheels in the pipeline. The wheels on the side of the pipeline robot close to the center of the curve of the pipeline are referred to as inner wheels, and the wheels on the side of the pipeline robot away from the center of the curve of the pipeline are referred to as outer wheels.

[0061] The logic of calculating the centrifugal force imbalance degree is: analyzing the equivalent centrifugal forces of all wheels to obtain the centrifugal force imbalance degree.

[0062] The formula for calculating the centrifugal force imbalance degree is:

[0063]

[0064] wherein, is the centrifugal force imbalance degree of the pipeline robot, is the weight of the i-th wheel of the pipeline robot, is the total number of wheels, is the equivalent centrifugal force received by the i-th wheel of the pipeline robot, and the specific weight setting basis is: if the wheel is an outer wheel, the weight is set to 1, and if the wheel is an inner wheel, the weight is set to -1.

[0065] When the pipe robot is subjected to the effect of centrifugal force, the inner wheel and the outer wheel will produce different effects. Since the centrifugal force is directed to the outer wheel, the pipe robot has a tendency to evert, so the centrifugal effect on the outer wheel is to tighten the outer wheel, while the centrifugal effect on the inner wheel is to relax the wheel, the effects are completely opposite. Therefore, this is the inevitable result of the pipe robot subjected to the centrifugal force. However, for the whole system, the real cause of the unstable posture of the pipe robot is the comprehensive imbalance after the centrifugal effect of the inner and outer wheels is offset. The centrifugal imbalance reflects the comprehensive imbalance after the centrifugal effect of the inner and outer wheels is offset, and reflects the net evert tendency caused by the centrifugal force. The larger the value is, the more serious the comprehensive imbalance after the centrifugal effect of the outer wheel is offset, and the greater the evert tendency, which needs a large compensation, and vice versa.

[0066] The jitter acceleration is the maximum jitter acceleration in the last control cycle. Since the pipe robot has a high jitter frequency, a representative maximum jitter acceleration is needed to represent the comprehensive jitter situation. If the maximum can keep the pipe robot stable, other moments will be easier to keep the pipe robot stable. Therefore, the jitter acceleration is the maximum jitter acceleration in the last control cycle. One control cycle is 30-70 seconds.

[0067] The pipe robot will produce jitter when it runs, which will also cause the posture of the pipe robot to be unstable. Relatively speaking, the influence caused by the centrifugal force is smaller, but it cannot be ignored.

[0068] The formula for calculating the jitter compensation torque is:

[0069]

[0070] For the jitter compensation torque of the pipe robot, is the component of the jitter acceleration of the pipe robot in the direction of the pipe robot motion, is the wheel radius;

[0071] is the force generated by the jitter in the direction of the pipe robot motion, according to the formula of torque, is the torque of the wheel of the pipe robot in the direction of the pipe robot motion. Since the directions of all the wheels are approximately directed to the direction of the pipe motion, the torque of the wheel of the pipe robot in the direction of the pipe motion is calculated by The jitter compensation torque of each wheel is analyzed. The jitter compensation torque considers the influence of the jitter of the pipe robot on the posture of the pipe robot, which can make the posture analysis of the pipe robot more accurate.

[0072] The centrifugal compensation moment is a first centrifugal compensation moment or a second centrifugal compensation moment, and the second centrifugal compensation moment is greater than the first centrifugal compensation moment. A preset centrifugal force imbalance threshold is provided. If the centrifugal force imbalance is less than the centrifugal force imbalance threshold, it indicates that the influence of the centrifugal force on the posture of the pipeline robot is relatively small, and a smaller centrifugal compensation moment, i.e., the first centrifugal compensation moment, can be used. If the centrifugal force imbalance is not less than the centrifugal force imbalance threshold, it indicates that the influence of the centrifugal force on the posture of the pipeline robot is relatively large, and a larger centrifugal compensation moment, i.e., the second centrifugal compensation moment, needs to be used. The second centrifugal compensation moment is used as the centrifugal compensation moment. In this embodiment, the posture instability of the pipeline robot caused by the centrifugal force is analyzed by the centrifugal force imbalance threshold, different centrifugal compensation moments are used for compensation according to different situations, and more accurate adaptive control is achieved.

[0073] The first centrifugal compensation moment and the second centrifugal compensation moment are preset centrifugal compensation moments, which can be determined by experts in the field according to the actual structure and control system of the pipeline robot. First, the critical compensation moment at which the pipeline robot will lose stability at a typical curve speed is measured through experiments or simulations. Since the compensation moment is the superposition of various moments, at this time, the centrifugal force is the most important factor. Therefore, 50% of the critical compensation moment is set as the first centrifugal compensation moment, which is used to cope with slight centrifugal force imbalance. 85% of the critical centrifugal force moment is set as the second centrifugal compensation moment.

[0074] Further, the reverse of the reverse compensation moment is the direction opposite to the motion.

[0075] If the integrated roll angle deviates to the outside of the curve, a reverse compensation moment with the sum of the centrifugal compensation moment and the jitter compensation moment is applied to the inner side wheel, and a reverse compensation moment with the size of the jitter compensation moment is applied to the outer side wheel.

[0076] Since the direction of the jitter compensation moment is the motion direction, the inner side wheel and the outer side wheel both have jitter in the motion direction, so the jitter compensation moment needs to be applied to both sides of the wheel. If the integrated roll angle deviates to the outside of the curve, it indicates that the posture of the pipeline robot in the pipeline is that the inner side wheel is high and the outer side wheel is low, and the centrifugal force has a tendency to overturn the pipeline robot. A reverse compensation moment with the size of the centrifugal compensation moment is also needed to be applied to the inner side wheel to form a speed difference and offset the tendency to overturn the pipeline robot, so a reverse compensation moment with the sum of the centrifugal compensation moment and the jitter compensation moment needs to be applied to the inner side wheel.

[0077] If the integrated roll angle deviates to the inside of the curve, a reverse compensation moment with the size of the jitter compensation moment is applied to the inner side wheel and the outer side wheel.

[0078] Since the direction of the jitter compensation moment is the moving direction, the inner wheel and the outer wheel both have jitter in the moving direction, so the jitter compensation moment needs to be applied to both sides of the wheel. If the comprehensive roll angle deviates to the inner side of the curve, it indicates that the posture of the pipe robot in the pipe is that the outer wheel is high and the inner wheel is low at this time. At this time, the overturning trend caused by the centrifugal force is directly offset by the support force of the pipe on the pipe robot, so the centrifugal compensation moment is not needed to compensate, and only the jitter compensation moment in the moving direction needs to be compensated.

[0079] In the embodiment, considering the actual posture of the pipe robot when passing the curve of the pipe, it is determined whether the centrifugal moment compensation needs to be performed according to the actual posture, and the adaptive stability control in the pipe is completed.

[0080] Step 4: The jitter acceleration of the pipe robot after the compensation strategy is executed is measured, and is compared with the jitter acceleration before the compensation strategy is executed, and whether the compensation strategy is qualified is judged according to the comparison result, if not qualified, then step 5 is entered;

[0081] Generally, after the compensation strategy is executed, the compensation strategy is qualified, but since the centrifugal compensation moment is a preset constant value, in the case of extremely large or extremely small centrifugal force, the effect of the compensation strategy may be small, or even have a reverse effect. In the case of only having enough control margin (the safety margin is not less than the safety margin threshold value), the compensation strategy can be performed, otherwise, if in the extreme case, the pipe robot cannot maintain stability, and accidents may occur directly. Since the effect of the compensation strategy may be small, or even have a reverse effect, the stability of the pipe robot after compensation needs to be verified to ensure the posture stability of the pipe robot.

[0082] Further, the jitter acceleration of the pipe robot after the compensation strategy is executed is obtained, if the jitter acceleration of the pipe robot is less than the jitter acceleration before the compensation strategy is executed, it is judged that the compensation strategy is qualified, otherwise, the compensation strategy is not qualified.

[0083] Step 5: The deceleration step and the centrifugal iteration termination condition are set, the current speed is iteratively reduced according to the deceleration step, if the centrifugal iteration termination condition is met, the speed of the pipe robot is reduced to the speed at the iteration termination; if the centrifugal iteration termination condition is not met within a preset iteration number, the speed of the pipe robot is halved.

[0084] Further, the deceleration strategy is specifically: the deceleration step is set, the current speed is iteratively reduced according to the deceleration step, and the equivalent centrifugal force and the centrifugal force imbalance degree are calculated, if the centrifugal iteration termination condition is met, the speed of the pipe robot is reduced to the speed at the iteration termination; if the centrifugal iteration termination condition is not met within a preset iteration number, the speed of the pipe robot is halved;

[0085] The centrifugal iteration termination condition is that the equivalent centrifugal force is less than a preset centrifugal force threshold value, and the centrifugal force imbalance degree is less than a centrifugal force imbalance degree threshold value.

[0086] The application further provides a pipeline robot posture stability control system, which is used for the pipeline robot posture stability control method and specifically comprises the following components:

[0087] A centrifugal analysis module is configured to acquire speed data, curve curvature data and the roll angle of each wheel of the robot in the pipeline curve, and analyze and determine the equivalent centrifugal force at each wheel of the pipeline robot.

[0088] A strategy selection module is configured to set a limit roll angle, determine a safety margin based on the limit roll angle and the roll angle, and determine a control strategy according to the safety margin, wherein the control strategy is a deceleration strategy or a compensation strategy.

[0089] A strategy compensation module is configured to determine a centrifugal force imbalance degree based on the equivalent centrifugal force at all wheels, and further determine a centrifugal compensation torque; determine a comprehensive roll angle of the pipeline robot based on the roll angle of the wheels, acquire the shaking acceleration of the pipeline robot, determine a shaking compensation torque based on the shaking acceleration, determine a reverse compensation torque of each wheel based on the positional relationship between the wheels and the curve center, the centrifugal force imbalance degree, the centrifugal compensation torque, the comprehensive roll angle, the shaking acceleration and the shaking compensation torque, and apply the reverse compensation torque to each wheel by applying a torque to the wheels.

[0090] A compensation evaluation module is configured to measure the shaking acceleration of the pipeline robot after the compensation strategy is executed, and compare the shaking acceleration with the shaking acceleration before the compensation strategy is executed, and determine whether the compensation strategy is qualified according to the comparison result.

[0091] A strategy deceleration module is configured to set a deceleration step and a centrifugal iteration termination condition, decelerate the current speed according to the deceleration step, and reduce the speed of the pipeline robot to the speed at the iteration termination if the centrifugal iteration termination condition is met, or halve the speed of the pipeline robot if the centrifugal iteration termination condition is not met within a preset iteration number.

[0092] The above formulas are dimensionless values, and the formulas are obtained by collecting a large amount of data to simulate a formula closest to the actual situation, and the preset parameters in the formulas are set by a person skilled in the art according to the actual situation.

[0093] The above-described embodiments can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented by software, the above-described embodiments can be implemented in whole or in part in the form of a computer program product. A person of skill in the art can be aware that units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on the specific application and design constraints of the technical solution.

[0094] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, and can be located in one place or distributed on multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiments according to actual needs.

[0095] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art cannot easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for posture stabilization control of a pipe robot, characterized by, The specific steps include: Step 1: acquiring speed data, curvature data of the bend and the roll angle of each wheel of the robot in the pipeline, and analyzing to determine the equivalent centrifugal force at each wheel of the pipeline robot; Step 2: setting a limit roll angle, determining a safety margin based on the limit roll angle and the roll angle, determining a control strategy according to the safety margin, the control strategy being a deceleration strategy or a compensation strategy, if the compensation strategy is adopted, proceeding to step 3, if the deceleration strategy is adopted, proceeding to step 5; Step 3: determining the centrifugal force imbalance degree based on the equivalent centrifugal force at all wheels, and further determining a centrifugal compensation torque, determining a comprehensive roll angle of the pipeline robot based on the roll angle of the wheel, acquiring the shaking acceleration of the pipeline robot, determining a shaking compensation torque based on the shaking acceleration, determining a reverse compensation torque for each wheel based on the positional relationship between the wheel and the center of the bend, the centrifugal force imbalance degree, the centrifugal compensation torque, the comprehensive roll angle, the shaking acceleration and the shaking compensation torque, and applying the reverse compensation torque to each wheel by applying a torque to the wheel; Step 4: measuring the shaking acceleration of the pipeline robot after the compensation strategy is executed, and comparing it with the shaking acceleration before the compensation strategy is executed, judging whether the compensation strategy is qualified according to the comparison result, if not, proceeding to step 5; Step 5: setting a deceleration step and a centrifugal iteration termination condition, decelerating the current speed by the deceleration step, if the centrifugal iteration termination condition is met, reducing the speed of the pipeline robot to the speed at the iteration termination, if the centrifugal iteration termination condition is not met within a preset iteration number, reducing the speed of the pipeline robot by half; The wheels are divided into inner wheels and outer wheels based on the position of the wheels in the pipeline, the wheels on the side of the pipeline robot close to the center of the pipeline bend are referred to as inner wheels, and the wheels on the side of the pipeline robot away from the center of the pipeline bend are referred to as outer wheels; The logic for calculating the centrifugal force imbalance degree is that the equivalent centrifugal forces of all wheels are analyzed to obtain the centrifugal force imbalance degree; The formula for calculating the centrifugal force imbalance degree is: wherein, is the centrifugal force imbalance degree of the pipe robot, is the weight of the i-th wheel of the pipe robot, is the total number of wheels, is the equivalent centrifugal force received by the i-th wheel of the pipe robot, and the specific weight setting is as follows: if the wheel is an outer wheel, the weight is set to 1, and if the wheel is an inner wheel, the weight is set to -1. The shaking acceleration is the maximum shaking acceleration in the last control cycle; The formula for calculating the shaking compensation torque is: a shaking compensation torque for the pipe robot, a component of the shaking acceleration of the pipe robot in the direction of motion of the pipe robot, a wheel radius, a mass of the pipe robot; The centrifugal compensation torque is a first centrifugal compensation torque or a second centrifugal compensation torque, and the second centrifugal compensation torque is greater than the first centrifugal compensation torque, a preset centrifugal force imbalance degree threshold is set, if the centrifugal force imbalance degree is less than the centrifugal force imbalance degree threshold, the first centrifugal compensation torque is used as the centrifugal compensation torque, if the centrifugal force imbalance degree is not less than the centrifugal force imbalance degree threshold, the second centrifugal compensation torque is used as the centrifugal compensation torque; If the comprehensive roll angle is inclined to the outside of the bend, a reverse compensation torque of the sum of the centrifugal compensation torque and the shaking compensation torque is applied to the inner wheels, and a reverse compensation torque of the shaking compensation torque is applied to the outer wheels; If the comprehensive roll angle is inclined to the inside of the bend, a reverse compensation torque of the shaking compensation torque is applied to the inner wheels and the outer wheels. The shaking acceleration of the pipeline robot after the compensation strategy is executed is obtained, if the shaking acceleration of the pipeline robot is less than the shaking acceleration before the compensation strategy is executed, it is judged that the compensation strategy is qualified, otherwise, the compensation strategy is unqualified.

2. The method of claim 1, wherein: The direction pointing to the center of the curved channel is called the inner side of the curved channel, and the direction opposite to the inner side of the curved channel is called the outer side of the curved channel; if the roll angle deviates to the outer side of the curved channel, the roll angle is set as a positive value, if the roll angle deviates to the inner side of the curved channel, the roll angle is set as a negative value, the comprehensive roll angle is the sum of all roll angles, if the comprehensive roll angle is a positive value, the comprehensive roll angle deviates to the outer side of the curved channel, if the comprehensive roll angle is a negative value, the comprehensive roll angle deviates to the inner side of the curved channel; The formula for calculating the equivalent centrifugal force is: wherein, is the equivalent centrifugal force experienced by the i-th wheel of the pipe robot, is the mass of the pipe robot, is the velocity of the pipe robot, is the radius of curvature of the bend at the location of the pipe robot; is the roll angle of the i-th wheel of the pipe robot, the roll angle of the wheel being the angle between the wheel and the vertical upward direction, i being the index of the wheel.

3. The method of claim 1, wherein The logic for obtaining the safety margin is: comparing the absolute values of the roll angles of each wheel to determine the maximum absolute value of the roll angle, calculating the difference between the limit roll angle and the maximum absolute value of the roll angle, which is the safety margin, presetting a safety margin threshold, if the safety margin is less than the safety margin threshold, using the deceleration strategy for control, if the safety margin is not less than the safety margin threshold, using the compensation strategy for control.

4. The method of claim 1, wherein: The deceleration strategy is specifically: setting a deceleration step, decelerating the current speed according to the deceleration step, and calculating the equivalent centrifugal force and the centrifugal force imbalance degree, iterating, if the centrifugal iteration termination condition is met, the speed of the pipeline robot is reduced to the speed at the iteration termination; If the centrifugal iteration termination condition is not met within the preset number of iterations, the speed of the pipeline robot is halved; The centrifugal iteration termination condition is that the equivalent centrifugal force is less than a preset centrifugal force threshold, and the centrifugal force imbalance degree is less than a centrifugal force imbalance degree threshold.

5. A pipeline robot pose stabilization control system, characterized by: The system is used to implement the pipeline robot posture stability control method of any one of claims 1-4, and specifically comprises: A centrifugal analysis module is configured to obtain speed data, curved channel curvature data, and the roll angle of each wheel of the robot in the curved channel of the pipeline, and analyze and determine the equivalent centrifugal force at each wheel of the pipeline robot. A strategy selection module is configured to set a limit roll angle, determine a safety margin based on the limit roll angle and the roll angle, and determine a control strategy according to the safety margin, wherein the control strategy is a deceleration strategy or a compensation strategy, if the compensation strategy is adopted, step 3 is performed, and if the deceleration strategy is adopted, step 5 is performed. A strategy compensation module is configured to determine a centrifugal force imbalance degree based on the equivalent centrifugal force at all wheels, and further determine a centrifugal compensation torque, determine a comprehensive roll angle of the pipeline robot based on the roll angle of each wheel, obtain a shaking acceleration of the pipeline robot, determine a shaking compensation torque based on the shaking acceleration, determine a reverse compensation torque of each wheel based on the positional relationship between the wheels and the center of the curved channel, the centrifugal force imbalance degree, the centrifugal compensation torque, the comprehensive roll angle, the shaking acceleration, and the shaking compensation torque, and apply the reverse compensation torque to each wheel by applying a torque to the wheel. A compensation evaluation module is configured to measure the shaking acceleration of the pipeline robot after the compensation strategy is executed, and compare it with the shaking acceleration before the compensation strategy is executed, and determine whether the compensation strategy is qualified according to the comparison result, if not, step 5 is entered. A strategy deceleration module is configured to set a deceleration step and a centrifugal iteration termination condition, to perform a deceleration iteration on the current speed according to the deceleration step, to reduce the speed of the pipeline robot to the speed at the iteration termination if the centrifugal iteration termination condition is met, and to halve the speed of the pipeline robot if the centrifugal iteration termination condition is not met within a preset iteration number.

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