A scene-adaptive robot self-adjusting wrist joint and control method thereof

Abstract

The present invention discloses a scene-adaptive robot self-adjusting wrist joint and a control method thereof, aiming to provide a structure capable of adjusting the angle of the wrist joint according to the movement requirements of a wall-climbing robot. The wrist structure adopts a two-stage adjustment mechanism, and realizes wrist angle adjustment and suction cup angle fine-tuning respectively through a wrist adjustment mechanism and a suction cup fine-tuning structure, and carries an inertial measurement unit on the suction cup to sense its angle information in real time. The controller adjusts the orientation of the adsorption device according to the target angle and the angle information fed back by the inertial measurement unit by a closed-loop control method to adapt to the changes in the wall angle and the posture of the wall-climbing robot. The wrist joint has the advantages of a wide angle adjustment range, a strong load capacity, a high adjustment accuracy, and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and in particular to a scene-adaptive robot self-adjusting wrist joint and a control method thereof. Background Art

[0002] A wall-climbing robot is a robot designed to crawl on vertical or inclined surfaces. They are often used in building inspections, maintenance operations, search and rescue missions, and pipeline inspections. Traditional wall-climbing robots often rely on the following main technologies or functions:

[0003] Adsorption technologies: These technologies allow the robot to remain fixed on vertical surfaces. Common adhesion technologies include using vacuum suction cups, magnetic materials, or using piercing the surface to achieve gripping effects.

[0004] Mobility and Navigation: Robots are typically equipped with wheels, feet, tracks, or other mechanisms for mobility, and require navigation systems to ensure that the robot can effectively locate and plan paths in uncertain environments.

[0005] Control systems: Advanced control technologies ensure that robots can respond to emergencies, automatically adjust their behavior according to environmental changes, and complete more complex tasks.

[0006] The wrist structure is the mechanical interface between the robot body and the robot foot (which may include adhesion devices or other contact surfaces). This part is critical to the performance of the robot because they need to remain stable at different contact angles and surfaces. However, most existing wall-climbing robots have rigid wrist joints or very limited range of motion. The rigid structure cannot adjust according to the changes in the robot's posture relative to the wall, which may cause the adhesion to weaken or even fall off.

[0007] Therefore, the prior art still needs to be improved and enhanced. Summary of the invention

[0008] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a scene-adaptive robot self-adjusting wrist joint and a control method thereof, aiming to solve the problem that most of the wall-climbing robots in the prior art are rigid in design of the wrist joint, or the movable range of the joint is very limited, and the rigid structure cannot be adjusted according to the changes in the robot's posture relative to the wall, which may lead to weakened adhesion or even falling off.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] In a first aspect, a scene-adaptive wrist adjustment method for a mobile robot includes a controller, which further includes:

[0011] A wrist adjustment mechanism, one end of which is connected to the end of the leg of the foot-type mobile robot;

[0012] A suction cup fine-adjustment mechanism connected to the other end of the wrist adjustment mechanism;

[0013] A suction cup assembly, hinged at the center of the suction cup fine-tuning mechanism;

[0014] The inertial measurement unit is arranged on the suction cup fine-tuning mechanism.

[0015] Furthermore, the wrist adjustment mechanism comprises:

[0016] A fixing seat connected to the end of the leg of the foot-type mobile robot by bolts;

[0017] A first transmission mechanism is disposed on the fixed seat;

[0018] a second transmission mechanism, hinged to the first transmission mechanism;

[0019] A first drive motor is provided on the second transmission mechanism and is meshedly connected with the first transmission mechanism through gears;

[0020] The second drive motor is disposed on the second transmission mechanism and is meshedly connected with the second transmission mechanism through gears.

[0021] Furthermore, the first transmission mechanism comprises:

[0022] A first worm gear bracket is arranged on the fixing seat, and a bracket hole is provided on the first worm gear bracket;

[0023] A first worm gear is keyed to the first worm gear bracket;

[0024] The first worm is arranged on the second transmission mechanism and meshedly connected with the first worm wheel.

[0025] Furthermore, the second transmission mechanism comprises:

[0026] A second worm gear bracket, wherein the second worm gear bracket is provided with a rotating shaft and a worm gear center axis, the rotating shaft is provided with a disc, the second worm gear bracket is rotatably connected to the first worm gear bracket via the rotating shaft passing through the bracket hole, and the second worm gear bracket is provided with a positioning hole;

[0027] A second worm gear is hinged to the second worm gear bracket through the worm gear center axis and connected to the suction cup fine-tuning mechanism;

[0028] The second worm is arranged in the positioning hole and meshedly connected with the second worm wheel.

[0029] Furthermore, the suction cup fine-tuning mechanism comprises:

[0030] A suction cup support frame connected to the wrist adjustment mechanism;

[0031] At least three third drive motors are arranged on the suction cup support frame at circumferential intervals at an angle of 120°;

[0032] A lead screw connected to the third drive motor;

[0033] A slider, slidably connected to the suction cup support frame and connected to the lead screw;

[0034] At least two thrust bearings are provided at opposite ends of the slider;

[0035] A rotatable hinge connected to the slider via one of the thrust bearings;

[0036] A connecting rod, one end of which is connected to the slider via the rotatable hinge;

[0037] The sliding sleeve is connected to the other ends of the three connecting rods and is located at the center of the suction cup support frame.

[0038] Furthermore, the suction cup assembly comprises:

[0039] Suction cup;

[0040] A connecting rod is arranged on the suction cup, and an axial limiting protrusion and a circumferential limiting protrusion are arranged on the connecting rod. The connecting rod is connected to the sliding sleeve via the circumferential limiting protrusion.

[0041] Furthermore, the suction cup support frame is provided with a protrusion, and the protrusion is connected to the second worm gear.

[0042] Furthermore, the suction cup fine-tuning mechanism also includes:

[0043] A platform is extended and connected to the connecting rod to carry the inertial measurement unit.

[0044] In a second aspect, a method for controlling a wrist joint of a mobile robot by adaptively adjusting the scene, based on the above-mentioned method, comprises:

[0045] The inertial measurement unit is used to monitor the angle state of the suction cup in real time. When the legged mobile robot moves on the changing wall surface, the position and angle of the wall surface can be identified by equipping the robot with a camera or other visual sensors.

[0046] The tilt angle of the foot landing point is obtained through image processing algorithms, and this information is transmitted to the controller;

[0047] The controller calculates a control signal for adjusting the wrist joint according to the target angle, and converts the target angle into a control signal for the wrist adjustment mechanism;

[0048] The control signal is transmitted to the wrist adjustment mechanism, and the wrist adjustment mechanism adjusts the corresponding angle according to the signal so that the wrist achieves the desired tilt angle.

[0049] The technical solution adopted by the present invention has the following beneficial effects:

[0050] In the present application, the suction cup angle information detected by the inertial measurement unit is introduced into the controller as a feedback value for real-time processing. The controller adjusts the gain according to the feedback suction cup angle information and the desired target, and transmits the control signal to the three third drive motors of the suction cup fine-tuning mechanism to coordinately control the direction of the suction cup, thereby realizing closed-loop control of the mechanism and real-time adjustment, improving control accuracy and stability, and can also adjust and optimize the wrist posture through the wrist adjustment mechanism according to the requirements of different surfaces and environments, thereby improving the adaptability and application range of the robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of the structure of a scene-adaptive adjustment wrist joint of a mobile robot provided by the present invention;

[0052] Figure 2 A schematic diagram of the structure of a wrist adjustment mechanism for scene adaptive adjustment of the wrist joint of a mobile robot provided by the present invention;

[0053] Figure 3 A schematic diagram of the structure of a second worm gear support for scene-adaptive adjustment of a wrist joint of a mobile robot provided by the present invention;

[0054] Figure 4 A schematic diagram of the structure of a suction cup fine-tuning mechanism for scene-adaptive adjustment of the wrist joint of a mobile robot provided by the present invention;

[0055] Figure 5 A schematic diagram of the structure of a suction cup assembly for scene-adaptive adjustment of the wrist joint of a mobile robot provided by the present invention.

[0056] 1. Fixed seat; 2. First worm gear bracket; 3. Second worm gear bracket; 4. First drive motor; 5. First worm; 6. First worm gear; 7. Second worm; 8. Second worm gear; 9. Inertial measurement unit; 10. Universal hinge; 11. Top cover; 12. Suction cup; 13. Third drive motor; 31. Disc; 32. Rotating shaft; 33. Positioning hole; 34. Worm gear center axis; 14. Lead screw; 15. Slider; 16. Thrust bearing; 17. Rotatable hinge; 18. Connecting rod; 19. Sliding sleeve; 20. Suction cup support frame; 21. Axial limit protrusion; 22. Circumferential limit protrusion; 23. Extending platform. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0058] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component.

[0059] It should also be noted that the same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0060] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0061] In this example, see Figure 1 The mechanism adopts two structural schemes at the same time to realize the control of the direction of the suction cup 12. Through the superposition of the two structural movements, it realizes the characteristics of wide adjustment range and high adjustment accuracy.

[0062] It should be noted that, in the embodiment of the present invention, the first drive motor 4, the second drive motor and the third drive motor 13 are all reduced speed stepping motors, which can increase the working torque of the motors and achieve wide range adjustment.

[0063] The first structure is a wrist adjustment mechanism, which uses two pairs of worm gears and has a self-locking characteristic, which can greatly increase its load capacity. The first drive motor 4 drives the first transmission mechanism to control the wrist structure to rotate around the axial direction of the leg, and the second drive motor drives the second transmission mechanism to control the wrist structure to swing up and down around the axis of the second worm gear 8.

[0064] Wrist adjustment mechanism such as Figure 2 As shown, the fixing seat 1 is fixed to the end of the leg, the worm gear bracket is fixed to the fixing seat 1 by screw connection, and the first worm gear 6 is provided with a keyway and fixed to the first worm gear bracket 2. The second worm gear bracket 3 is provided with a rotating shaft 32 and a worm gear center axis 34, and the rotating shaft 32 is provided with a disc 31. The second worm gear bracket 3 is rotatably connected to the first worm gear bracket 2 through the rotating shaft 32 passing through the bracket hole, and the second worm gear bracket 3 is provided with a positioning hole 33.

[0065] The second worm gear support 3 Figure 3 As shown, the rotating shaft 32 matches the bracket hole of the first worm gear bracket 2, the disc 31 is sandwiched between the first worm gear bracket 2 and the fixing seat 1, and the rotating shaft 32 of the second worm gear bracket 3 can rotate. Therefore, when the first drive motor 4 drives the first worm wheel 6 to rotate through gear transmission, the first worm 5 moves circumferentially along the first worm wheel 6. The first drive motor 4 and the second drive motor are placed on the second worm gear bracket 3 close to the suction cup 12 to reduce the distance between the leg end and the adsorption structure, and the structure is more compact. The foot end of the wall-climbing robot is driven by the first worm 5 to rotate around the axis of the leg, and the rotation range can reach 360 degrees.

[0066] When the second drive motor drives the second worm 7 to rotate, the second worm wheel 8 drives the foot end to rotate around the worm wheel central axis 34. By controlling the forward and reverse rotation of the second drive motor, the up and down swing of the foot end of the wall-climbing robot can be controlled; when the first drive motor 4 drives the first worm 5 to rotate, the first worm 5 rotates around the axis of the first worm wheel 6, driving the second worm wheel bracket 3 and the suction cup 12 assembly behind the bracket and other components to rotate around the axis of the first worm wheel 6, thereby realizing universal adsorption.

[0067] The second structure is a fine-tuning mechanism for the suction cup 12, which uses a deceleration stepper motor to drive the lead screw 14 to rotate to push the slider 15, and also has a self-locking characteristic. Specifically, in this embodiment, the suction cup support frame 20 is connected to the wrist adjustment mechanism; at least three third drive motors 13 are arranged on the suction cup support frame 20 at an angle of 120°; the lead screw 14 is connected to the third drive motor 13; the slider 15 is slidably connected to the suction cup support frame 20 and connected to the lead screw 14; at least two thrust bearings 16 are arranged at opposite ends of the slider 15; the rotatable hinge 17 is connected to the slider 15 through one of the thrust bearings 16; one end of the connecting rod 18 is connected to the slider 15 through the rotatable hinge 17; the sliding sleeve 19 is connected to the other end of the three connecting rods 18 and is located at the center of the suction cup support frame 20.

[0068] In addition, the suction cup 12 assembly is composed of a suction cup 12 and a connecting rod. The connecting rod is arranged on the suction cup 12, and an axial limit protrusion 21 and a circumferential limit protrusion 22 are arranged on the connecting rod. The connecting rod is connected to the sliding sleeve 19 through the circumferential limit protrusion 22. The suction cup 12 is connected to the top cover 11 on the suction cup support frame 20 through the universal hinge 10, and has two degrees of freedom. When the three third driving motors 13 drive the slider 15 to move to a certain position respectively, due to the provision of the rotatable hinge 17, the slider 15 can further drive the connecting rod 18 to push the sleeve to move downward along the connecting rod. After moving to the limit position, the suction cup 12 rotates to the corresponding angle with the driving of the third driving motor 13. There is an opening on the top cover 11, and a protruding platform 23 is arranged on the protruding suction cup 12 rod to facilitate the installation of the sensor or other measuring elements. The inertial measurement unit 9 installed thereon can sense the angle of the suction cup 12 in real time.

[0069] Figure 4 In the figure, the third driving motor 13 is a reduction stepping motor, the angle between two adjacent reduction stepping motors is 120 degrees, and they are fixed on the suction cup support frame 20. Each lead screw 14 driven by the reduction stepping motor is equipped with a slider 15. When the reduction stepping motor rotates forward and backward, the slider 15 can move forward and backward along the axis of the lead screw 14. There is a hole on the upper part of the slider 15, on which a rotatable hinge 17 that can rotate around the axis of the slider 15 hole is installed. In order to ensure the smoothness of rotation and reduce friction, a thrust bearing 16 is installed before and after the slider 15 hole respectively. The rotatable hinge 17 is connected to the connecting rod 18 in an articulated manner, so that the connecting rod 18 can realize axial rotation and swing around the hinge. The connecting rod 18 is connected to the sliding sleeve 19 by a ball joint. When the slider 15 moves forward and backward, the sliding sleeve 19 can be driven to move accordingly. When the three sliders 15 move together, the sliding sleeve 19 can drive the suction cup 12 rod to swing freely in any direction.

[0070] The mechanism uses a three-directional deceleration stepper motor. When the mechanism is working, the sliding sleeve 19 will be simultaneously subjected to upward and downward forces along the direction of the suction cup 12 rod. These forces will offset each other so that the sliding sleeve 19 is in a relatively balanced position. In order to further ensure the certainty of the position of the sliding sleeve 19, axial limiting protrusions 21 are respectively provided at the upper and lower ends of the sliding sleeve 19 in the working area of ​​the suction cup 12 rod. Figure 5 As shown. In addition, in order to limit the rotation of the sleeve 19 on the rod of the suction cup 12, a circumferential limit protrusion 22 is also provided on the rod of the suction cup 12. In this way, when the reduction stepper motor drives the slider 15 to move and thus drives the connecting rod 18 and the sleeve 19, the suction cup 12 will swing along the desired direction and angle. In order to monitor the angle of the suction cup 12, a sensor mounting platform is provided on the rod of the suction cup 12. The platform is parallel to the bottom surface of the suction cup 12. The angle state of the suction cup 12 can be monitored by using the inertial measurement unit 9 to monitor the angle of the platform.

[0071] In the process of the leg-type wall-climbing robot moving or overcoming obstacles, it is very important to keep the adsorption device (suction cup 12) relatively vertical to the wall surface. The present invention designs a control method, which specifically includes the following contents:

[0072] The inertial measurement unit 9 is used to monitor the angle state of the suction cup 12 in real time. When the wall-climbing robot moves on the changing wall surface, its body is equipped with a camera or other visual sensor to identify the position and angle of the wall surface. Through the image processing algorithm, the inclination angle of the foot end landing point is obtained, and this information is transmitted to the control system. The control system calculates the control signal for adjusting the wrist adjustment mechanism according to the target angle, and converts the target angle into the control signal of the wrist adjustment mechanism. The control signal is transmitted to the wrist adjustment mechanism, and the wrist adjustment mechanism adjusts the corresponding angle according to the signal so that the wrist achieves the desired inclination angle.

[0073] Specifically, the controller calculates the number of pulses required for the suction cup 12 to reach the target angle, and controls the accurate number of steps of the first drive motor 4 and the second drive motor driving the worm gear by adjusting the pulse signal to achieve angle positioning. The two pairs of worm gears work together, and the controller simultaneously sends control signals to the first drive motor 4 and the second drive motor driving the two pairs of worm gears, and the wrist mechanism simultaneously performs rotation and pitch movements to achieve rapid adjustment of the wrist posture.

[0074] During the actual operation of the mechanism, due to the existence of errors, there is often a deviation between the actual angle of the suction cup 12 and the expected angle. To solve this problem, it is necessary to use the suction cup 12 fine-tuning mechanism for adjustment. The suction cup 12 angle information detected by the inertial measurement unit 9 is introduced into the controller as a feedback value for real-time processing. The controller adjusts the gain according to the feedback suction cup 12 angle information and the expected target, and transmits the control signal to the three third drive motors 13 of the suction cup 12 angle fine-tuning mechanism to coordinately control the direction of the suction cup 12, thereby realizing closed-loop control of the mechanism. When the difference between the suction cup 12 angle information measured by the inertial measurement unit 9 and the expected angle is within the allowable error range, the control system issues "leg drop" and "adsorb on the wall" commands to the wall-climbing robot. After completing an adsorption cycle, the suction cup 12 angle fine-tuning mechanism returns to its original position when the leg is raised.

[0075] However, when the wall-climbing robot lowers its legs, the angle of the suction cup 12 changes with the angle of the legs. During the movement of the wall-climbing robot, the angle between the legs in the adsorption state and the wall also changes. Therefore, the angle of the suction cup 12 needs to be dynamically adjusted to maintain the ideal angle between the suction cup 12 and the wall.

[0076] When the wall surface is a flat, unchanging plane, since the sensor on the suction cup 12 detects the angle of the suction cup 12 relative to the earth's surface, the target angle change of the foot end of the wall-climbing robot can be ignored, and real-time control is performed with the suction cup 12 perpendicular to the wall surface as a fixed target angle.

[0077] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the schemes disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed in this disclosure. The description and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the claims.

Claims

1. A scene-adaptive wrist joint of a mobile robot, comprising a controller, characterized in that: It also includes: A wrist adjustment mechanism, one end of which is connected to the end of the leg of the foot-type mobile robot; A suction cup fine-tuning mechanism is connected to the other end of the wrist adjustment mechanism, and the suction cup fine-tuning mechanism includes: A suction cup support frame connected to the wrist adjustment mechanism; At least three third drive motors are arranged on the suction cup support frame at circumferential intervals at an angle of 120°; A lead screw connected to the third drive motor; A slider, slidably connected to the suction cup support frame and connected to the lead screw; At least two thrust bearings are provided at opposite ends of the slider; A rotatable hinge connected to the slider via one of the thrust bearings; A connecting rod, one end of which is connected to the slider via the rotatable hinge; A sliding sleeve connected to the other end of the three connecting rods and located at the center of the suction cup support frame; A suction cup assembly is hinged at the center of the suction cup fine-tuning mechanism, and is composed of a suction cup and a connecting rod. The connecting rod is arranged on the suction cup, and an axial limiting protrusion and a circumferential limiting protrusion are arranged on the connecting rod. The connecting rod is connected to the sliding sleeve through the circumferential limiting protrusion. The inertial measurement unit is arranged on the suction cup fine-tuning mechanism.

2. The scene-adaptive wrist joint of a mobile robot according to claim 1, characterized in that: The wrist adjustment mechanism comprises: A fixing seat connected to the end of the leg of the foot-type mobile robot by bolts; A first transmission mechanism is disposed on the fixed seat; a second transmission mechanism, hinged to the first transmission mechanism; A first drive motor is provided on the second transmission mechanism and is meshedly connected with the first transmission mechanism through gears; The second drive motor is disposed on the second transmission mechanism and is meshedly connected with the second transmission mechanism through gears.

3. The scene-adaptive wrist joint of a mobile robot according to claim 2, characterized in that: The first transmission mechanism comprises: A first worm gear bracket is arranged on the fixing seat, and a bracket hole is provided on the first worm gear bracket; A first worm gear is keyed to the first worm gear bracket; The first worm is arranged on the second transmission mechanism and meshedly connected with the first worm wheel.

4. The scene-adaptive wrist joint of a mobile robot according to claim 3, characterized in that: The second transmission mechanism comprises: A second worm gear bracket, wherein the second worm gear bracket is provided with a rotating shaft and a worm gear center axis, the rotating shaft is provided with a disc, the second worm gear bracket is rotatably connected to the first worm gear bracket via the rotating shaft passing through the bracket hole, and the second worm gear bracket is provided with a positioning hole; A second worm gear is hinged to the second worm gear bracket through the worm gear center axis and connected to the suction cup fine-tuning mechanism; The second worm is arranged in the positioning hole and meshedly connected with the second worm wheel.

5. The scene-adaptive wrist joint of a mobile robot according to claim 4, characterized in that: The suction cup support frame is provided with a protrusion, and the protrusion is connected to the second worm gear.

6. The scene-adaptive wrist joint of a mobile robot according to claim 1, characterized in that: The suction cup fine-tuning mechanism also includes: A platform is extended and connected to the connecting rod to carry the inertial measurement unit.

7. A control method for scene-adaptive wrist adjustment of a mobile robot as claimed in claim 1, characterized in that: include: The inertial measurement unit is used to monitor the angle state of the suction cup in real time. When the foot-type mobile robot moves on the changing wall surface, the camera equipped on its body can identify the position and angle of the wall surface. The tilt angle of the foot landing point is obtained through image processing algorithms, and this information is transmitted to the controller; The controller calculates a control signal for adjusting the wrist joint according to the target angle, and converts the target angle into a control signal for the wrist adjustment mechanism; The control signal is transmitted to the wrist adjustment mechanism, and the wrist adjustment mechanism adjusts the corresponding angle according to the signal so that the wrist achieves the desired tilt angle.

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