A stable multi-degree-of-freedom holder and a mobile robot having the holder

Abstract

The application discloses a stable multi-degree-of-freedom holder, which comprises a base, a yaw shaft mechanism, a pitch shaft mechanism and a vertical lifting mechanism. A mobile robot comprising the stable multi-degree-of-freedom holder is also disclosed. The application has the advantages that the whole vertical stabilizing mechanism is simulated as a second-order damping system comprising a virtual spring and a virtual damper, different damping ratios and resonance frequencies can be obtained by adjusting different parameters, the influence of the environment on the load can be effectively reduced when the mobile robot runs on a low-bump road, and the stability is good.

Description

Technical Field

[0001] This invention relates to the technical field of gimbals, and more specifically to a stable multi-degree-of-freedom gimbal and a mobile robot having the gimbal. Background Technology

[0002] Mobile robots possess the ability to move across a wide range of terrains and have high payload capacity and long endurance, making them widely used in military, agriculture, and inspection fields. In recent years, researchers have begun to add end-effector payloads, such as cameras and LiDAR, to mobile robots in practical applications, deploying algorithms such as Simultaneous Localization and Mapping (SLAM) and path planning to achieve more efficient proactive perception tasks. Typical application scenarios include disaster relief and field research.

[0003] However, in the aforementioned scenarios, mobile robots often face harsh and bumpy terrain, including high-frequency, low-impact terrain such as gravel roads and low-frequency, high-impact terrain such as steps. The impacts from these rugged terrains lead to extreme instability in the images transmitted by the mobile robot, as well as degradation of its sensor systems and perception algorithms, resulting in divergent perception and loss of localization. Disaster relief particularly emphasizes the stability of the images transmitted by the mobile robot; only stable images allow rescuers to quickly determine the specific conditions of disaster scenes such as fires and ruins. Field investigations involve tasks such as high-precision map creation and navigation, requiring feature point matching from cameras or radar. This necessitates sufficiently stable images from the camera or radar itself, providing enough feature points for computer processing.

[0004] Chinese invention patent application CN115256398A discloses a multi-functional indoor operating robot for substations. The robot's base is equipped with a lidar, gyroscope, and core controller. The base also includes pit avoidance sensors, obstacle avoidance sensors, and an antenna. A core control board, discharge detection sensor, safety edge sensor, and support frame are mounted on the base. A binocular gimbal is located on top of the support frame, and a high-precision six-axis robotic arm with operating tools and a depth camera is mounted on the arm base. The depth camera uses QR code information and a depth map correction method to accurately analyze and calculate the positional relationship between the end effector and the target. An operating seat is mounted on the support frame and connected to a five-axis linkage grounding switch operating mechanism via a rotating shaft. Compared to existing technologies, this invention, through its unique structure and component design, can enter substations to perform various switching operations on switchgear. The binocular gimbal is equipped with a high-definition visible light camera and a high-precision infrared thermal imager to acquire image data of the surrounding environment. However, this structure is difficult to use in complex, bumpy outdoor environments, and the poor stability of the gimbal can easily lead to blurred images output by the camera. The stability of existing gimbal structures cannot meet the usage requirements, and they suffer from poor stability. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a stable multi-degree-of-freedom gimbal, comprising a base, a yaw axis mechanism, a pitch axis mechanism, and a vertical lifting mechanism. It also provides a mobile robot comprising the aforementioned stable multi-degree-of-freedom gimbal, which has the advantage of good stability.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0007] A stable multi-degree-of-freedom gimbal includes a base, a yaw axis mechanism, a pitch axis mechanism, and a vertical lifting mechanism. The vertical lifting mechanism is mounted on the base, the yaw axis mechanism is mounted on the vertical lifting mechanism, and the pitch axis mechanism is mounted on the yaw axis mechanism. The pitch axis mechanism has a load mounting base. The vertical lifting mechanism includes an optical axis, a lifting seat, a connecting rod, a sliding seat, and a lifting drive component. The optical axis is fixedly mounted on the base, the lifting seat is vertically slidably connected to the optical axis, the sliding seat is slidably connected to the base, and the lifting drive component is mounted on the sliding seat. One end of the connecting rod is fixedly connected to the output shaft of the lifting drive component, and the other end of the connecting rod is hinged to the lifting seat. The lifting drive component simulates a second-order damped system including a virtual spring and a virtual damper on the vertical lifting mechanism by outputting torque. A virtual model controller simulates the thrust output by the virtual spring and virtual damper on the lifting seat. The force output by the virtual model controller on the lifting seat... ,in, This represents the spring constant of the virtual spring. This represents the damping coefficient of the virtual damper. This indicates the height of the lifting seat when the base is subjected to bumps. Indicates the height of the base. This represents the initial length of the virtual spring when it is at rest.

[0008] By setting the entire vertical stabilizing mechanism as a second-order damping system containing virtual springs and virtual dampers, different damping ratios and resonant frequencies can be obtained by adjusting different parameters. This effectively addresses environmental interference, reduces the impact on the load when running on bumpy roads, and achieves better stability.

[0009] Preferably, the torque output by the lifting drive component is... It conforms to the following formula: ,in, Indicates the length of the connecting rod. This indicates the position and height of the connection point between the connecting rod and the lifting drive component.

[0010] This setup allows us to obtain the motor torque needed to simulate the z-axis as a virtual model controller, facilitating the control of the output torque of the lifting drive components. It also enables real-time acquisition of the lifting drive component torque data, which, after processing, can be easily used for future expansion and upgrades.

[0011] Preferably, the base is equipped with a distance sensor, which is used to detect the position and height of the lifting seat.

[0012] With this setting, the height of the lifting seat relative to the base can be substituted into the formula for calculation.

[0013] Preferably, the yaw axis mechanism includes a support base, a yaw bearing, a yaw drive component, a flange, and a yaw mounting bracket. The support base and the yaw drive component are both fixedly mounted on a lifting base. The support base is fixedly connected to the outer ring of the yaw bearing. The output shaft of the yaw drive component is connected to the flange. The flange is fixedly connected to the inner ring of the yaw bearing. The yaw mounting bracket is fixedly connected to the inner ring of the yaw bearing. The pitch axis mechanism is mounted on the yaw mounting bracket.

[0014] This configuration enables yaw axis adjustment, significantly reduces the axial and radial load on the yaw drive components by utilizing yaw bearings, improves the reliability of the yaw drive components, and expands the application scenarios.

[0015] Preferably, the pitch axis mechanism includes a pitch mounting bracket, a pitch drive component, and a rotating shaft. The pitch drive component is fixedly mounted on the yaw axis mechanism. The pitch mounting bracket is rotatably connected to the yaw axis mechanism. The two ends of the rotating shaft are fixedly connected to the output end of the pitch drive component and the pitch mounting bracket, respectively.

[0016] This setting enables pitch axis adjustment.

[0017] Preferably, the base is fixedly connected to a support frame, the support frame is fixedly connected to a support plate, the support plate is fixedly connected to the end of the optical axis away from the base, and the support frame has a weight-reducing cavity inside.

[0018] This setting improves the stability of the optical axis.

[0019] Preferably, the optical axis is provided with sleeves at both ends, and the sleeves at both ends of the optical axis are fixedly connected to the support plate and the base respectively. The sleeves are provided with movable grooves, and the sleeves are provided with fixing members that pass through the movable grooves.

[0020] This setting allows for the fixation of the optical axis.

[0021] Preferably, the optical axis is provided with a linear bearing, and the linear bearing is fixedly connected to the lifting seat.

[0022] This design makes the movement of the lifting seat smoother.

[0023] Preferably, a shock-absorbing pad is provided between the sliding seat and the base.

[0024] This configuration ensures the stability of the lifting drive components.

[0025] A mobile robot comprising the aforementioned stable multi-degree-of-freedom gimbal.

[0026] This configuration effectively addresses environmental interference, reduces the impact on load when running on bumpy roads, and achieves good stability.

[0027] Compared with the prior art, the present invention has achieved beneficial technical effects:

[0028] 1. The entire vertical stabilizing mechanism is simulated as a second-order damping system containing virtual springs and virtual dampers. By adjusting different parameters, different damping ratios and resonant frequencies can be obtained, thereby effectively dealing with environmental interference and effectively reducing the impact on the load when running on bumpy roads, achieving the advantage of good stability.

[0029] 2. A vertical lifting mechanism allows for adjustment of the lifting seat's position along the vertical z-axis on an optical axis that remains relatively constant relative to the base. The lifting seat can carry a load and offers advantages such as structural stability, smooth movement, and rapid response. Three optical axes are evenly distributed around the lifting seat, restricting its movement trajectory. The lifting drive component drives a connecting rod, using the vertical component of the connecting rod's end velocity to lift the gimbal. The lifting drive component is mounted on a sliding seat on a horizontal rail to neutralize the horizontal component of the crank's end velocity. This mechanism occupies minimal space, has a low gimbal height, low frictional resistance in the direction of movement, and is less prone to jamming. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a stable multi-degree-of-freedom gimbal in Embodiment 1 of the present invention;

[0031] Figure 2 This is a schematic diagram of the internal structure of the yaw shaft mechanism in Embodiment 1 of the present invention;

[0032] Figure 3 This is a schematic diagram of the z-axis motion of a stable multi-degree-of-freedom gimbal mounted on a chassis in Embodiment 1 of the present invention;

[0033] Figure 4 This is a schematic diagram of the amplitude-frequency response of the z-axis controller in Embodiment 1 of the present invention;

[0034] Figure 5 This is a mobile robot in Embodiment 2 of the present invention.

[0035] The technical features referred to by the various reference numerals in the accompanying drawings are as follows:

[0036] 11. Base; 12. Distance sensor; 13. Support frame; 14. Support plate; 15. Weight reduction cavity; 21. Optical axis; 22. Sleeve; 23. Movable slot; 24. Fixing component; 25. Linear bearing; 31. Lifting seat; 32. Connecting rod; 33. Sliding seat; 34. Lifting drive component; 35. Shock-absorbing pad; 41. Support seat; 42. Yaw bearing; 43. Yaw drive component; 44. Flange; 45. Yaw mounting bracket; 51. Pitch mounting bracket; 52. Pitch drive component; 53. Rotary shaft. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. However, the scope of protection of this invention is not limited to the specific embodiments described below.

[0038] Example 1:

[0039] refer to Figure 1 and Figure 2A stable multi-degree-of-freedom gimbal includes a base 11, a yaw axis mechanism, a pitch axis mechanism, and a vertical lifting mechanism. The vertical lifting mechanism is mounted on the base 11, the yaw axis mechanism is mounted on the vertical lifting mechanism, the pitch axis mechanism is mounted on the yaw axis mechanism, and the pitch axis mechanism is provided with a load mounting base.

[0040] The vertical lifting mechanism includes an optical shaft 21, a lifting seat 31, a connecting rod 32, a sliding seat 33, and a lifting drive component 34. The optical shaft 21 is fixedly mounted on the base 11 and is vertically oriented. The lifting seat 31 is vertically slidably connected to the optical shaft 21, and the sliding seat 33 is slidably connected to the base 11. The lifting drive component 34 is mounted on the sliding seat 33. One end of the connecting rod 32 is fixedly connected to the output shaft of the lifting drive component 34, and the other end of the connecting rod 32 is hinged to the lifting seat 31. A support frame 13 is fixedly connected to the base 11, and a support plate 14 is fixedly connected to the support frame 13. The support plate 14 is fixedly connected to the end of the optical shaft 21 away from the base 11. A weight-reducing cavity 15 is provided inside the support frame 13. Sleeves 22 are provided at both ends of the optical shaft 21. The sleeves 22 at both ends of the optical shaft 21 are fixedly connected to the support plate 14 and the base 11, respectively. The sleeves 22 are provided with movable grooves 23, and fixing components 24, which are screws, are provided through the movable grooves 23. The optical axis 21 is equipped with a linear bearing 25, which is fixedly connected to the lifting seat 31. A shock-absorbing pad 35 is provided between the sliding seat 33 and the base 11. A distance sensor 12 is installed on the base 11. The distance sensor 12 is used to detect the position and height of the lifting seat 31. The distance sensor 12 is a wire sensor.

[0041] The yaw axis mechanism includes a support base 41, a yaw bearing 42, a yaw drive component 43, a flange 44, and a yaw mounting bracket 45. The support base 41 and the yaw drive component 43 are both fixedly mounted on the lifting base 31. The support base 41 is fixedly connected to the outer ring of the yaw bearing 42. The output shaft of the yaw drive component 43 is connected to the flange 44. The flange 44 is fixedly connected to the inner ring of the yaw bearing 42. The yaw mounting bracket 45 is fixedly connected to the inner ring of the yaw bearing 42. The pitch axis mechanism is mounted on the yaw mounting bracket 45. The yaw bearing 42 is a crossed roller bearing.

[0042] The pitch axis mechanism includes a pitch mounting bracket 51, a pitch drive component 52, and a rotating shaft 53. The pitch drive component 52 is fixedly mounted on the yaw axis mechanism. The pitch mounting bracket 51 is rotatably connected to the yaw axis mechanism. The two ends of the rotating shaft 53 are fixedly connected to the output end of the pitch drive component 52 and the pitch mounting bracket 51, respectively.

[0043] The lifting drive component 34, the yaw drive component 43, and the pitch drive component 52 are all motors.

[0044] The lifting drive component 34 simulates a second-order damping system containing a virtual spring and a virtual damper on the vertical lifting mechanism by outputting torque. A virtual model controller is set up to simulate the virtual spring and virtual damper outputting thrust on the lifting seat 31.

[0045] refer to Figure 3 In this embodiment, the stable multi-degree-of-freedom gimbal is mounted on the chassis of the mobile robot. First, assuming the gimbal's z-axis is vertical, the moving parts along the z-axis include the lifting seat 31, the yaw axis mechanism, the pitch axis mechanism, and the load above them. The initial flat ground height is... The initial height of the lifting seat 31 is In the initial state, the height of base 11 is The distance between the lifting platform 31 and the top of the gimbal is The mass of the moving part along the z-axis is The chassis mass is When the ground becomes bumpy, the current height of the bumpy terrain where the mobile robot is located is... The height of the base 11 is The height of the lifting seat 31 is It is also assumed that the mobile robot chassis has no suspension system, meaning that the connection between the ground and the chassis can be considered rigid.

[0046] At this point, in order to simulate a second-order damped suspension system between the gimbal's lifting seat 31 and the chassis, the lifting drive component 34 needs to drive the connecting rod 32 to apply an external force to the lifting seat 31. Assume the initial length of the virtual spring in the gimbal virtual model controller is... The stiffness coefficient is The damping coefficient of the virtual damper is .

[0047] In the initial stationary state of the mobile robot, the virtual spring is compressed to compensate for the gravity of the moving part of the gimbal along the z-axis. This is the gravity feedforward compensation term in the virtual model controller:

[0048]

[0049] When the mobile robot encounters a protruding obstacle on the ground, the virtual spring continues to be compressed under the inertia of its moving part along the z-axis. Ignoring gravity, the elastic force output of this part is:

[0050]

[0051] Because the chassis and the moving parts of the gimbal along the z-axis move at different speeds, the virtual damper is also compressed, and its damping force output is:

[0052]

[0053] In summary, the output of the virtual model controller is:

[0054]

[0055] in The item can be obtained through the distance sensor 12 placed on the base 11. The term is obtained by differentiating the data measured by distance sensor 12.

[0056] In this way, this patent simulates a second-order damped suspension system between the chassis and the z-axis moving part of the gimbal. Following the analysis method of automobile suspension, the following force equations can be written:

[0057]

[0058] Rearranging the terms, we have:

[0059]

[0060] This patent selects ground terrain height. The second derivative The advantage of choosing this as the system input research object is that it can be regarded as the external disturbance force experienced by the mobile robot; at the same time, the acceleration of the load on the moving part of the gimbal is selected. This selection of the system output as the research object allows for the study of interference affecting the gimbal load. If, after filtering by the virtual suspension, the acceleration experienced by the gimbal load is much less than the second derivative of the terrain height, then the virtual model controller designed in this patent can be considered effective.

[0061] Since this patent assumes a rigid connection between the ground and the chassis, then:

[0062]

[0063]

[0064] Therefore:

[0065]

[0066] The virtual model controller proposed in this patent is analyzed from the perspective of the system transfer function. Taking a Laplace transform on both sides of the equation, we get:

[0067]

[0068] In the formula, s is the complex frequency domain variable of the Laplace transform, and X g The height of the moving part along the Z-axis is x. g The Laplace transform result, X wground terrain height x w The result of the Laplace transform.

[0069] in:

[0070]

[0071]

[0072] Therefore, we have the transfer function:

[0073]

[0074] If we consider the impact of terrain on the vehicle body as interference, then we have:

[0075]

[0076] Right now:

[0077]

[0078] As can be seen, this patent actually constructs an equivalent second-order low-pass filter with a cutoff frequency of:

[0079]

[0080] The damping ratio is:

[0081]

[0082] Its amplitude-frequency response is as follows Figure 4 As shown in the bottom right corner.

[0083] This patent samples the acceleration of a mobile robot along the z-axis under a bumpy environment from a simulation. With a mass of 1, the acceleration can be considered as an external disturbance force. The original data, the data with the controller, and the frequency domain analysis are all as follows: Figure 4 As shown.

[0084] As can be seen, under external impact, due to the compliant control of the virtual model, the acceleration of the system is much smaller than the acceleration caused by the external force, and the controller performs as expected.

[0085] To achieve the force provided by the virtual model controller to the z-axis load It is necessary to calculate the torque required by the motor. This force is generated by the motor driving connecting rod 32, and the force on connecting rod 32 is distributed to the z-axis portion, such as... Figure 3 As shown. Therefore, the formula for calculating motor torque is:

[0086]

[0087]

[0088]

[0089] Solving the simultaneous formulas, we have:

[0090]

[0091] in, This indicates the length of link 32. This indicates the position and height of the connection point between the connecting rod 32 and the lifting drive component 34.

[0092] In summary, this patent yields the motor torque required to simulate a virtual second-order system along the z-axis. By adjusting different virtual stiffness and virtual damping coefficients, a virtual second-order damped system with different responses can be obtained.

[0093] This embodiment has the following advantages:

[0094] The entire vertical lifting mechanism is simulated as a second-order damping system containing virtual springs and virtual dampers. By adjusting different parameters, different damping ratios and resonant frequencies can be obtained, thereby effectively dealing with environmental interference and reducing the impact on the load when running on bumpy roads, achieving the advantage of good stability.

[0095] The motor torque required to simulate the z-axis as a virtual model controller was obtained, facilitating the control of the output torque of the lifting drive component 34. By adjusting different virtual stiffness and virtual damping coefficients, a virtual second-order damping system with different responses can be obtained. Real-time torque data of the lifting drive component 34 can be obtained, and after processing, it can be easily used for subsequent expansion and upgrades.

[0096] The vertical lifting mechanism allows for adjustment of the lifting seat 31 along the vertical z-axis direction on the optical axis 21, which remains unchanged relative to the base 11. The lifting seat 31 can carry a load and features structural stability, smooth movement, and rapid response. Three optical axes 21 are evenly distributed around the lifting seat 31, thus limiting its movement trajectory. The lifting drive component 34 drives the connecting rod 32, using the vertical component of the velocity at the end of the connecting rod 32 to lift the gimbal. The lifting drive component 34 is mounted on a sliding seat 33 on a horizontal slide rail to eliminate the horizontal component of the crank's end velocity. The mechanism occupies little space, has a low gimbal height, low frictional resistance in the direction of movement, and is less prone to jamming.

[0097] The distance sensor 12 can detect the position and height of the lifting seat 31 when it is subjected to bumps, and thus the height of the lifting seat 31 relative to the base 11 can be substituted into the formula for calculation.

[0098] The yaw drive component 43 drives the inner ring of the yaw bearing 42 via the flange 44, which in turn drives the yaw mounting bracket 45 to rotate. The yaw mounting bracket 45 then drives the pitch axis mechanism and load to deflect, thus achieving the function of yaw axis adjustment. The support seat 41 provides support force to the yaw bearing 42, which in turn significantly reduces the axial and radial load on the yaw drive component 43, improving the reliability of the yaw drive component 43 and expanding its application scenarios.

[0099] The pitch mount 51 is used to mount a load, such as a camera. The pitch drive 52 drives the pitch mount 51 to rotate via the pivot 53, causing the pitch mount 51 and the load to flip, thereby realizing the function of pitch axis adjustment.

[0100] The optical axis 21 is further supported by the support frame 13 and the support plate 14, which improves the stability of the optical axis 21 and thus improves the overall stability of the system.

[0101] By setting the movable groove 23, the fixing member 24 passing through the movable groove 23 can pull the sleeve 22 material on both sides of the movable groove 23, so that the sleeve 22 material retracts into the movable groove 23 and clamps the optical axis 21, thereby fixing the optical axis 21 and facilitating the installation and removal of the optical axis 21.

[0102] The linear bearing 25 makes the movement of the lifting seat 31 more stable.

[0103] By setting the shock-absorbing pad 35, the impact on the lifting drive component 34 when the robot travels over bumpy roads can be reduced, thereby improving the stability of the lifting drive component 34.

[0104] Example 2:

[0105] refer to Figure 5 A mobile robot includes a chassis and a stable multi-degree-of-freedom gimbal as described in Embodiment 1. A camera mounted on the gimbal first acquires point cloud data. An algorithm then converts the point cloud data into a raster map, extracts elevation information from the raster map, converts the elevation information into a HoG feature operator, and uses IMU-based driving mode classification as the label for SVM machine learning, with the HoG feature operator as input for training. Subsequently, in a real-world operating environment, the model can directly obtain the expected driving mode from the HoG feature operator, while dynamically adjusting the gimbal control parameters.

[0106] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the invention.

Claims

1. A stable multi-degree-of-freedom gimbal, comprising a base (11), a yaw axis mechanism, and a pitch axis mechanism, characterized in that: It also includes a vertical lifting mechanism, which is mounted on a base (11). The yaw axis mechanism is mounted on the vertical lifting mechanism, and the pitch axis mechanism is mounted on the yaw axis mechanism. The pitch axis mechanism is provided with a load mounting seat. The vertical lifting mechanism includes an optical axis (21), a lifting seat (31), a connecting rod (32), a sliding seat (33), and a lifting drive component (34). The optical axis (21) is fixedly mounted on the base (11). The lifting seat (31) is vertically slidably connected to the optical axis (21). The sliding seat (33) is connected to the base (11). 11) Sliding connection, the lifting drive (34) is mounted on the sliding seat (33), one end of the connecting rod (32) is fixedly connected to the output shaft of the lifting drive (34) and the other end of the connecting rod (32) is hinged to the lifting seat (31); the lifting drive (34) simulates a second-order damping system including a virtual spring and a virtual damper on the vertical lifting mechanism by outputting torque, and a virtual model controller is set to simulate the virtual spring and virtual damper outputting thrust on the lifting seat (31), and the force output by the virtual model controller on the lifting seat (31) is... ,in, This represents the spring constant of the virtual spring. This represents the damping coefficient of the virtual damper. This indicates the position and height of the lifting seat (31) when the base (11) is subjected to bumps. Indicates the position and height of the base (11). This represents the initial length of the virtual spring when it is at rest.

2. The stable multi-degree-of-freedom gimbal according to claim 1, characterized in that: The torque output by the lifting drive (34) It conforms to the following formula: ,in, Indicates the length of link (32), This indicates the position and height of the connection point between the connecting rod (32) and the lifting drive component (34).

3. The stable multi-degree-of-freedom gimbal according to claim 1, characterized in that: The base (11) is equipped with a distance sensor (12), which is used to detect the position and height of the lifting seat (31).

4. The stable multi-degree-of-freedom gimbal according to claim 1, characterized in that: The yaw axis mechanism includes a support base (41), a yaw bearing (42), a yaw drive (43), a flange (44), and a yaw mounting bracket (45). The support base (41) and the yaw drive (43) are both fixedly mounted on the lifting base (31). The support base (41) is fixedly connected to the outer ring of the yaw bearing (42). The output shaft of the yaw drive (43) is connected to the flange (44). The flange (44) is fixedly connected to the inner ring of the yaw bearing (42). The yaw mounting bracket (45) is fixedly connected to the inner ring of the yaw bearing (42). The pitch axis mechanism is mounted on the yaw mounting bracket (45).

5. The stable multi-degree-of-freedom gimbal according to claim 1, characterized in that: The pitch axis mechanism includes a pitch mounting bracket (51), a pitch drive (52), and a rotating shaft (53). The pitch drive (52) is fixedly mounted on the yaw axis mechanism. The pitch mounting bracket (51) is rotatably connected to the yaw axis mechanism. The two ends of the rotating shaft (53) are fixedly connected to the output end of the pitch drive (52) and the pitch mounting bracket (51), respectively.

6. The stable multi-degree-of-freedom gimbal according to claim 1, characterized in that: The base (11) is fixedly connected to a support frame (13), the support frame (13) is fixedly connected to a support plate (14), the support plate (14) is fixedly connected to the end of the optical axis (21) away from the base (11), and the support frame (13) is provided with a weight reduction cavity (15).

7. The stable multi-degree-of-freedom gimbal according to claim 1, characterized in that: The optical axis (21) is provided with sleeves (22) at both ends. The sleeves (22) at both ends of the optical axis (21) are fixedly connected to the support plate (14) and the base (11) respectively. The sleeves (22) are provided with movable grooves (23) and the sleeves (22) are provided with fixing members (24) passing through the movable grooves (23).

8. The stable multi-degree-of-freedom gimbal according to claim 1, characterized in that: The optical axis (21) is provided with a linear bearing (25), and the linear bearing (25) is fixedly connected to the lifting seat (31).

9. The stable multi-degree-of-freedom gimbal according to claim 1, characterized in that: A shock-absorbing pad (35) is provided between the sliding seat (33) and the base (11).

10. A mobile robot, characterized in that: The stable multi-degree-of-freedom gimbal includes any one of claims 1-9.

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