Force constraint reducing omnidirectional pipeline robot based on Mecanum wheels and control method

Abstract

The invention discloses a force constraint reducing omnidirectional pipeline robot based on Mecanum wheels. The force constraint reducing omnidirectional pipeline robot comprises a laser radar, at least three driving wheel sets arranged in a central symmetry mode and a modular rack. Each driving wheel set is composed of a swing rod, a synchronous belt transmission structure, a pair of Mecanum wheels, a driving motor and a reducing motor. The variable-diameter motor is in linkage with the swing rod through the double-rope-winding mechanism, the radial extension amplitude of the wheel set is accurately adjusted, and the device is adaptive to the inner diameters of different pipelines. Omnidirectional movement of the robot is achieved through rotation direction combination and differential control of the Mecanum wheels. The laser radar collects pipeline contour data in real time, motion parameters are dynamically adjusted in combination with the multi-axis motion controller, and stable operation in a complex pipeline environment is ensured. Through modular wheel set layout, active reducing adjustment and high-degree-of-freedom motion control, the problems that a traditional robot is limited in motion and poor in reducing adaptability are solved, and the robot is particularly suitable for intelligent inspection and maintenance tasks of narrow, bent and reducing pipelines.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline robots, and specifically, to a force-constrained variable-diameter omnidirectional pipeline robot based on Mecanum wheels and a control method therefor. Background Art

[0002] As the core carrier for transporting energy such as oil and natural gas, the safety and reliability of pipelines are directly related to industrial production efficiency, environmental protection, and public safety. However, during long-term operation, pipelines are prone to leakage due to aging, corrosion, foundation settlement, or external force damage. Especially in the scenarios of transporting high-risk media (such as methane and hydrogen sulfide), leakage may trigger major accidents such as combustion and explosion, and environmental pollution. Traditional detection methods mainly rely on manual inspection, acoustic wave monitoring, or fixed sensors, which have problems such as low efficiency, high cost, and poor real-time performance. Moreover, it is difficult to cover elbows, variable diameters, and multi-branch areas in complex pipe networks, resulting in significant detection blind spots and missed detection risks.

[0003] In recent years, pipeline robot technology has gradually become a research hotspot for solving the above problems. Although existing wheeled or tracked pipeline robots can achieve basic movement functions, traditional drive structures (such as fixed wheel sets or tracks) are difficult to turn flexibly in narrow pipelines, especially unable to continuously rotate around their own axes, resulting in limited sensor vision and high missed detection rates. Moreover, most robots rely on rigid structures and lack an active variable-diameter adjustment mechanism, making it difficult to adapt to different pipe diameters or cross-section mutation areas, and prone to jamming. In addition, existing robots mostly adopt a single drive mode and cannot coordinately adjust the rotational speed and radial position of the wheel sets, resulting in slow attitude adjustment and poor motion stability under complex working conditions. Finally, traditional designs are difficult to adapt to diverse task requirements through modular adjustment of the number of wheel sets, rotation directions, or sensor configurations. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a force-constrained variable-diameter omnidirectional pipeline robot based on Mecanum wheels and a control method therefor. A drive structure composed of multiple groups of Mecanum wheels with different rotation directions and an omnidirectional wheel set forms a closed force structure with the inner wall of the pipeline. By driving the wheel sets at different rotational speeds and directions, the pipeline robot can move forward, backward, turn, spin, and move in a spiral in the pipeline, increasing the flexibility of the pipeline robot body. Moreover, the high integration of the Mecanum wheel drive structure is fully utilized to simplify the drive mechanism of the pipeline robot, improve the operating stability, and enable it to adapt to the detection work in high-speed and highly complex pipeline environments.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is: a force-constrained variable-diameter omnidirectional pipeline robot based on Mecanum wheels, including a frame, a lidar is provided at one end of the frame, and at least three groups of drive wheel sets are provided on the frame; Each of the drive wheel sets includes a variable-diameter motor at the center. On both sides of the variable-diameter motor, a first drive motor and a second drive motor are respectively fixed. The drive shafts of the first drive motor and the second drive motor are respectively movably arranged on different swing rods. A first right-handed Mecanum wheel and a second right-handed Mecanum wheel are respectively arranged on the two swing rods; Between the first drive motor and the first right-handed Mecanum wheel, and between the second drive motor and the second right-handed Mecanum wheel, they are respectively in transmission cooperation through synchronous transmission belts; The variable-diameter motor is linked with the swing rod through a winding rope to control the radial extension amplitude of the drive wheel set.

[0006] In a preferred solution, the number of the drive wheel sets is three to six groups, and multiple groups of drive wheel sets are arranged in central symmetry on the side wall of the frame.

[0007] In a preferred solution, a single group of the drive wheel set includes two wheel bodies, and the rotation combinations of the two wheel bodies include any of the following ways: Double right-handed Mecanum wheel set; Double left-handed Mecanum wheel set; Double omnidirectional drive wheel set; A Mecanum wheel drive wheel set with different rotation combinations composed of a right-handed Mecanum wheel set and a left-handed Mecanum wheel set; A right-handed Mecanum wheel set or a left-handed Mecanum wheel set and an omnidirectional drive wheel set.

[0008] In a preferred solution, when multiple groups of the drive wheel sets include omnidirectional drive wheel sets, the omnidirectional drive wheel sets are used to control the moving speed of the robot, and the Mecanum wheel sets are used to control the rotation direction and angle of the robot.

[0009] In a preferred solution, the winding path of the winding rope is: The winding rope starts from the variable-diameter drive motor, is symmetrically wound around the winding wheels on both sides of the swing rod, and then connected to the swing rod to form a closed-loop linkage structure.

[0010] In a preferred solution, the omnidirectional motion control of the robot includes forward, backward, turning, 360° self-rotation around its own axis, and spiral compound motion.

[0011] In a preferred solution, the lidar obtains the surrounding environment data in real time and transmits it to the control system in the frame for path planning and obstacle avoidance; The control system integrates a motor drive module and a multi-axis motion controller, and dynamically adjusts the motion parameters of the drive wheel set through the feedback data of the lidar.

[0012] Based on the above control method of a force-constrained variable-diameter omnidirectional pipeline robot based on Mecanum wheels, it includes the following steps: 1) Collect the contour data of the inner wall of the pipeline in real time through the lidar; 2) Calculate the change in the inner diameter of the pipeline based on the above contour data; 3) Generate a control signal for the variable-diameter motor based on the above change, and adjust the radial extension amplitude of the swing rod; 4) Generate a rotational speed difference command for the first drive motor and the second drive motor according to a preset motion path or real-time obstacle avoidance requirements, and control the steering and rotational speed combination of the drive wheel set; 5) Synchronously execute the control signals of the variable-diameter motor, the first drive motor, and the second drive motor to realize the adaptive movement of the robot inside the pipeline; The generation of the rotational speed difference command in step 4) includes: 4.1) Determine the steering configuration of the Mecanum wheels in each drive wheel set according to the target movement direction of the robot; 4.2) Calculate the target rotational speeds of the first drive motor and the second drive motor based on the steering configuration and the preset speed; 4.3) Output a pulse width modulation signal to the first drive motor and the second drive motor through a multi-axis motion controller.

[0013] In a preferred solution, in step 3), the generation of the control signal for the variable-diameter motor includes: 1) Calculate the target tightening or releasing length of the winding rope according to the change in the inner diameter of the pipeline; 2) Determine the target rotation angle of the variable-diameter motor based on the linear relationship between the winding rope length and the rotation angle of the variable-diameter motor; Output a pulse signal to the variable-diameter motor to execute the target rotation angle.

[0014] In a preferred solution, in step 5), the synchronous execution of the control signal is achieved in the following manner: Bind the adjustment command of the variable-diameter motor and the rotational speed commands of the first drive motor and the second drive motor into the same time series; Trigger the synchronous execution of each command through a real-time clock signal to ensure the timing consistency of variable-diameter adjustment and motion control.

[0015] A force-constrained variable-diameter omnidirectional pipeline robot and control method based on Mecanum wheels provided by the present invention, by adopting the above structure, has the following beneficial effects: (1) Through multiple groups of Mecanum wheel drive wheel sets arranged centrally symmetrically, combined with the hybrid layout of different rotation directions (left-handed, right-handed) and omnidirectional wheel sets, it is possible to flexibly control the rotational speed and steering combination of each wheel set, realize the forward, backward, turning, 360° continuous self-rotation around its own axis, and helical composite motion of the robot inside the pipeline, break through the limitation of the single motion mode of traditional wheeled robots, significantly expand the sensor detection range, eliminate the detection blind area, and is particularly suitable for the full-coverage detection of complex structures such as elbows and branch pipelines; (2)Adopt a variable-diameter drive motor and a double-rope linkage mechanism to precisely adjust the radial extension amplitude of the swing rod by tightening or releasing the ropes, enabling the wheel set to adapt to changes in the pipe inner diameter in real time (such as variable-diameter sections and cross-section mutation areas), ensuring that the wheel set always maintains a stable contact pressure with the pipe wall, and avoiding problems of jamming or slipping caused by pipe diameter differences in traditional rigid structures, thus greatly improving the passing ability and operation reliability of the robot in narrow, highly curved, and variable-diameter pipes; (3)The lidar obtains the three-dimensional contour data of the pipe in real time, and combines with a multi-axis motion controller to dynamically adjust the rotation speed and variable-diameter amplitude of the wheel set, realizing autonomous obstacle avoidance, path planning, and smooth switching of complex motion modes. Through technologies such as the linear relationship between the rope length and the rotation angle of the variable-diameter motor, and multi-motor collaborative pulse control, ensure the precise execution of motion parameters (such as speed and rotation angle), and improve the detection and positioning accuracy and operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the drawings and embodiments: Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0017] Figure 2 For the present invention Figure 1 is a schematic diagram of the endwise structure.

[0018] Figure 3 It is a schematic diagram of the drive wheel set structure of the present invention.

[0019] Figure 4 It is a schematic diagram of the detailed structure of the swing rod of the present invention.

[0020] Figure 5 It is a schematic diagram of the rope winding structure of the present invention.

[0021] Figure 6 It is a schematic diagram of the overall structure under another drive wheel set structure of the present invention.

[0022] Figure 7 It is a schematic diagram of the overall structure under the third drive wheel set structure of the present invention.

[0023] In the figure: lidar 1, first drive wheel set 2, swing rod 21, synchronous drive belt 22, first right-handed Mecanum wheel 23, first drive motor 24, second drive motor 25, second right-handed Mecanum wheel 26, variable-diameter motor 27, rope winding wheel 28, rope 29, second drive wheel set 3, third drive wheel set 4, frame 5, omnidirectional drive wheel set 6, Mecanum wheel drive wheel set with different rotation combinations 7, left-handed Mecanum wheel set 8, right-handed Mecanum wheel set 9. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Embodiment 1: AsFigures 1 to 3 As shown in the figure, this embodiment provides a force-constrained variable-diameter omnidirectional pipeline robot based on Mecanum wheels, including: Lidar 1: Installed at the front end of the frame 5, used to scan the inner wall contour of the pipeline in real time and generate three-dimensional environmental data.

[0025] Three groups of centrally symmetric drive wheel sets, including the first drive wheel set 2, the second drive wheel set 3, and the third drive wheel set 4: Each drive wheel set includes: Swing rod 21: Made of aluminum alloy, connected to the frame 5 at both ends through hinges, and a synchronous pulley mounting groove is provided in the middle; Synchronous drive belt 22: Includes a driving wheel, a driven wheel, and a synchronous belt. The driving wheel is fixedly connected to the output shafts of the first driving motor 24 and the second driving motor 25, and the driven wheel is coaxially installed with the first right-handed Mecanum wheel 23 and the second right-handed Mecanum wheel 26; The first right-handed Mecanum wheel 23 and the second right-handed Mecanum wheel 26: Symmetrically arranged on both sides of the swing rod 21, and achieve the same-speed reverse rotation through the synchronous belt drive structure 22; Variable-diameter drive motor 27: Fixed in the middle of the swing rod 21, connected to the two-sided rope winding wheels 28 through the rope 29. The rope 29 starts from the variable-diameter drive motor 27, bypasses the two-sided rope winding wheels 28 in turn, and is fixed to the end of the swing rod 21 to form a closed-loop linkage.

[0026] Frame 5: Adopts a carbon fiber frame structure, with a built-in lithium battery pack and a multi-axis motion controller. The controller communicates with the first driving motor 24, the second driving motor 25, the variable-diameter drive motor 27, and the lidar 1 through the CAN bus.

[0027] Working principle: Variable-diameter adjustment: When the inner diameter of the pipeline changes, the lidar 1 detects the pipe diameter data and transmits it to the controller. The controller calculates the target tightening length of the rope 29, drives the variable-diameter motor 27 to rotate, and pulls the swing rod 21 to extend outward or contract inward through the rope 29, so that the first right-handed Mecanum wheel 23 and the second right-handed Mecanum wheel 26 always adhere to the pipe wall.

[0028] Omnidirectional movement: Different movement modes are achieved by adjusting the rotational speed difference of the Mecanum wheels in the three groups of drive wheel sets. For example, when the three groups of wheel sets rotate in the same direction, the robot moves straight forward; when the two-sided wheel sets rotate in the opposite direction, the robot spins around the axis; when the wheel sets have differential cooperation, a spiral movement is achieved.

[0029] Embodiment 2: As Figure 6 shown, on the basis of the first embodiment, this embodiment replaces the first drive wheel set 2 with an omnidirectional wheel set 6, and the second drive wheel set 3 and the third drive wheel set 4 adopt left-handed Mecanum wheel sets 8.

[0030] The rollers of the omnidirectional wheel set 6 are arranged obliquely at 45°, supporting lateral sliding motion.

[0031] Motion mode optimization: The omnidirectional wheel set 6 is responsible for providing the lateral movement degree of freedom, and the second drive wheel set 3 and the third drive wheel set 4 provide longitudinal thrust and rotational torque; By controlling the rotation speed of the omnidirectional wheel set 6, the lateral offset of the robot within the bend is achieved, avoiding collision with the pipe wall.

[0032] Application scenario: Suitable for pipe environments with dense bends or requiring lateral obstacle avoidance.

[0033] Embodiment 3: As Figure 7 shown, this embodiment adopts a hybrid layout of a left-handed Mecanum wheel set 8, a right-handed Mecanum wheel set 9 and an omnidirectional wheel set 6, and the three wheel sets are annularly distributed at 120°.

[0034] Wheel set configuration: Left-handed Mecanum wheel set 8: Double left-handed Mecanum wheels, providing a counterclockwise rotational torque through differential control; Right-handed Mecanum wheel set 9: Double right-handed Mecanum wheels, providing a clockwise rotational torque through differential control; Omnidirectional wheel set 6: Two sets of omnidirectional wheels, supporting lateral compensation motion.

[0035] By adjusting the rotational speed difference between the left-handed Mecanum wheel set 8 and the right-handed Mecanum wheel set 9, the rotational angular velocity of the robot around the axis is controlled; The omnidirectional wheel set 6 dynamically adjusts the lateral thrust according to the pipe wall friction coefficient to ensure motion stability.

[0036] Advantages: In the variable diameter and bend composite area, the hybrid layout can simultaneously achieve high-speed rotation and precise pose adjustment, suitable for high-complexity detection tasks.

Claims

1. A force-constrained variable-diameter omnidirectional pipeline robot based on Mecanum wheels, characterized in that: It includes a frame (5), a lidar (1) is provided at one end of the frame (5), and at least three groups of drive wheel sets are provided on the frame (5); Each group of the drive wheel sets contains a variable-diameter motor (27) at the center. A first drive motor (24) and a second drive motor (25) are respectively fixed on both sides of the variable-diameter motor (27). The drive shafts of the first drive motor (24) and the second drive motor (25) are respectively movably arranged on different swing rods (21). A first right-handed Mecanum wheel (23) and a second right-handed Mecanum wheel (26) are respectively provided on the two swing rods (21); A synchronous drive belt (22) is respectively used for transmission and cooperation between the first drive motor (24) and the first right-handed Mecanum wheel (23), and between the second drive motor (25) and the second right-handed Mecanum wheel (26); The variable-diameter motor (27) is linked with the swing rod (21) through a rope (29) to control the radial extension amplitude of the drive wheel set.

2. The omnidirectional pipeline robot with variable diameter under force constraint based on Mecanum wheels according to claim 1, wherein: The number of the drive wheel sets is three to six groups, and multiple groups of drive wheel sets are symmetrically arranged at the side wall of the frame (5) in a central symmetry manner.

3. The omnidirectional pipeline robot with variable diameter under force constraint based on Mecanum wheels according to claim 2, wherein: A single group of the drive wheel sets includes two wheel bodies, and the rotation direction combinations of the two wheel bodies include any of the following methods: Double right-handed Mecanum wheel set (9); Double left-handed Mecanum wheel set (8); Full omnidirectional drive wheel set (6); A Mecanum wheel drive wheel set (7) composed of a right-handed Mecanum wheel set (9) and a left-handed Mecanum wheel set (8) with different rotation combinations; A right-handed Mecanum wheel set (9) or a left-handed Mecanum wheel set (8) and a full omnidirectional drive wheel set (6).

4. The omnidirectional pipeline robot with variable diameter under force constraint based on Mecanum wheels according to claim 3, wherein: When a full omnidirectional drive wheel set (6) is included in multiple groups of the drive wheel sets, the full omnidirectional drive wheel set (6) is used to control the moving speed of the robot, and the Mecanum wheel set is used to control the rotation direction and angle of the robot.

5. The omnidirectional pipeline robot with variable diameter under force constraint based on Mecanum wheels according to claim 1, wherein: The winding path of the rope (29) is: the rope (29) starts from the variable-diameter drive motor (27), is symmetrically wound around the rope wheels (28) on both sides of the swing rod (21), and then is connected to the swing rod (21) to form a closed-loop linkage structure.

6. The omnidirectional pipeline robot with variable diameter under force constraint based on Mecanum wheels according to claim 1, characterized in that: The omnidirectional motion control of the robot includes forward movement, backward movement, turning, 360° self-rotation around its own axis, and spiral compound movement.

7. The omnidirectional pipeline robot with variable diameter under force constraint based on Mecanum wheels according to claim 1, wherein: The lidar (1) acquires surrounding environment data in real time and transmits it to the control system in the frame (5) for path planning and obstacle avoidance; The control system integrates a motor drive module and a multi-axis motion controller, and dynamically adjusts the motion parameters of the drive wheel set through the data fed back by the lidar (1).

8. A control method for a force-constrained variable-diameter omnidirectional pipeline robot based on Mecanum wheels according to any one of claims 1-7, characterized in that It includes the following steps: 1) Collect the contour data of the inner wall of the pipeline in real time through the lidar (1); 2) Calculate the change amount of the inner diameter of the pipeline according to the above contour data; 3) Generate a control signal for the variable-diameter motor (27) based on the above change amount to adjust the radial extension amplitude of the swing rod (21); 4) Generate a rotational speed difference instruction for the first drive motor (24) and the second drive motor (25) according to the preset motion path or the real-time obstacle avoidance requirement, and control the steering and rotational speed combination of the drive wheel set; 5) Synchronously execute the control signals of the variable-diameter motor (27), the first drive motor (24), and the second drive motor (25) to realize the adaptive motion of the robot in the pipeline; The generation of the rotational speed difference instruction in step 4) includes: 4.1) Determine the steering configuration of the Mecanum wheels in each drive wheel set according to the target movement direction of the robot; 4.2) Calculate the target rotational speeds of each first drive motor (24) and second drive motor (25) based on the steering configuration and the preset speed; 4.3) Output a pulse width modulation signal to the first drive motor (24) and second drive motor (25) through a multi-axis motion controller.

9. The control method of a force-constrained variable-diameter omnidirectional pipeline robot based on Mecanum wheels according to claim 8, wherein: In step 3) above, the generation of the control signal for the variable diameter motor (27) includes: 1) Calculate the target tightening or releasing length of the winding rope (29) according to the change amount of the inner diameter of the pipeline; 2) Determine the target rotation angle of the variable diameter motor (27) based on the linear relationship between the length of the winding rope (29) and the rotation angle of the variable diameter motor (27); Output a pulse signal to the variable diameter motor (27) to execute the target rotation angle.

10. The control method of an omnidirectional pipeline robot with force-constrained variable diameter based on Mecanum wheels according to claim 8, characterized in that: In step 5) above, the synchronous execution of the control signal is achieved by the following method: Bind the adjustment instruction of the variable diameter motor (27) and the rotational speed instructions of the first drive motor (24) and second drive motor (25) into the same time series; Trigger the synchronous execution of each instruction through a real-time clock signal to ensure the timing consistency between the variable diameter adjustment and the motion control.

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