Mecanum wheel moving platform capable of adaptively balancing center of mass

Abstract

The invention relates to a Mecanum wheel moving platform capable of self-adaptively balancing the center of mass, which comprises a bearing platform, a Mecanum wheel train, a counterweight adjusting system and a controller, and is characterized in that the Mecanum wheel train comprises a plurality of Mecanum wheel mechanisms which are symmetrically mounted below the bearing platform; the balance weight adjusting system comprises a plurality of balance weight adjusting mechanisms with the number equal to that of the Mecanum wheel mechanisms, the multiple balance weight adjusting mechanisms are evenly installed above the bearing platform, and the controller is arranged on the bearing platform and electrically connected with the Mecanum wheel mechanisms and the balance weight adjusting mechanisms. The rotating speed of each Mecanum wheel is dynamically adjusted by controlling current output, and meanwhile, each counterweight adjusting mechanism is controlled to adjust the position of the counterweight block on the bearing platform according to the current signal, so that the mass center of the whole Mecanum wheel moving platform is self-adaptively balanced. The self-adaptive mass center balance in the moving process of the Mecanum wheel moving platform can be effectively achieved, the application range is wide, and the implementation cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of Mecanum wheel mobile platforms, and in particular to a Mecanum wheel mobile platform capable of adaptively balancing the center of mass. Background Art

[0002] The working principle of the Mecanum wheel is that the roller axis and the hub axis are arranged at 45° in space. A Mecanum wheel system usually consists of two sets of Mecanum wheels in a mirror relationship. The mechanism for achieving omnidirectional movement is that the roller is a grounding component, and its driving force can be decomposed into forward force and lateral force, and omnidirectional movement is achieved by offsetting or enhancing the forces. Therefore, the Mecanum wheel is driven separately. However, when the Mecanum wheel system is unevenly loaded, the Mecanum wheel in the direction of the center of mass offset will bear a greater load, resulting in an increase in the driving force, which in turn causes an increase in the component force, so that the forward force or lateral force cannot be completely offset, which causes the movement to deviate. This problem seriously limits the promotion of the Mecanum wheel, making its scope of application mostly concentrated in small cargo transportation, or designing it into a large Mecanum wheel system with 8 or 12 wheels, which greatly increases the cost. Summary of the invention

[0003] The object of the present invention is to provide a Mecanum wheel mobile platform capable of adaptively balancing the center of mass, which can effectively realize adaptive center of mass balance during the movement of the Mecanum wheel mobile platform, has a wide range of applications and low implementation cost.

[0004] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a Mecanum wheel mobile platform capable of adaptively balancing the center of mass, comprising a load-bearing platform, a Mecanum wheel train, a counterweight adjustment system and a controller, wherein the Mecanum wheel train comprises a plurality of Mecanum wheel mechanisms, wherein the plurality of Mecanum wheel mechanisms are symmetrically installed below the load-bearing platform, wherein the counterweight adjustment system comprises a plurality of counterweight adjustment mechanisms equal in number to the number of the Mecanum wheel mechanisms, wherein the plurality of counterweight adjustment mechanisms are evenly installed above the load-bearing platform, wherein the controller is disposed on the load-bearing platform and is electrically connected to each Mecanum wheel mechanism and the counterweight adjustment mechanism, respectively, so as to dynamically adjust the rotation speed of each Mecanum wheel by controlling the current output, and at the same time, each counterweight adjustment mechanism is controlled according to the current signal to adjust the position of the counterweight block thereon on the load-bearing platform, so as to adaptively balance the center of mass of the entire Mecanum wheel mobile platform.

[0005] Furthermore, the Mecanum wheel mechanism includes a servo driver, a drive motor, a first coupling, a reducer and a Mecanum wheel. The servo driver and the drive motor are installed below the load-bearing platform via a suspension mechanism. The output shaft of the drive motor is connected to the reducer via the first coupling, and the reducer is connected to the Mecanum wheel to drive the Mecanum wheel to rotate. The controller is electrically connected to the drive motor through the servo driver to adjust the current value in real time according to the speed control requirement of the Mecanum wheel, output a corresponding current signal to the drive motor to control its rotation, and sample the output current signal at the same time.

[0006] Furthermore, the counterweight adjustment mechanism includes a base, a slide rail, a counterweight motor, a second coupling, a screw and a counterweight block. The base is fixedly installed above the carrying platform, the counterweight motor is fixedly installed on the carrying platform, and its output shaft is fixedly connected to the horizontally arranged screw via the second coupling to drive the screw to rotate, the slide rail is arranged parallel to the screw and fixedly connected to the carrying platform, the counterweight block is spirally matched with the screw and slidingly matched with the slide rail at the same time, thereby converting the rotational motion of the screw into horizontal linear motion of the counterweight block; the controller is electrically connected to the counterweight motor to control the rotation of the counterweight motor, thereby changing the position of the counterweight block on the carrying platform.

[0007] Furthermore, the counterweight adjustment mechanism includes two slide rails, which are arranged in parallel on the left and right sides of the screw rod and fixedly connected to the bearing platform, and the counterweight block slides with the two slide rails at the same time; the counterweight adjustment mechanism also includes two bearing seats, which are respectively fixedly installed on the front and rear sides of the base, and the front and rear ends of the screw rod are rotatably connected to the base via the bearing seats, and the front and rear ends of the two slide rails are respectively fixedly connected to the bearing seats.

[0008] Further, the Mecanum wheel system includes four Mecanum wheel mechanisms, which are symmetrically arranged in pairs and distributed at the left front, right front, left rear and right rear positions below the carrying platform; the counterweight adjustment system includes four counterweight adjustment mechanisms, which are correspondingly arranged on the carrying platform above the corresponding Mecanum wheel mechanisms, the center of each counterweight adjustment mechanism coincides with the center of the corresponding Mecanum wheel in the vertical direction, and one end of each counterweight adjustment mechanism faces the geometric center of the mobile platform, so as to position each counterweight adjustment mechanism.

[0009] Furthermore, the counterweight motor on the Mecanum wheel mechanism is installed at one end close to the geometric center of the mobile platform.

[0010] Furthermore, the control logic of the Mecanum wheel mobile platform during operation is:

[0011] S1. When the Mecanum wheel mobile platform starts working, the system is initialized first; then, the controller outputs corresponding current signals to the drive motors through the servo drivers according to the speed control requirements, so as to drive each Mecanum wheel to rotate at a set speed;

[0012] S2. When the Mecanum wheel mobile platform is unevenly loaded, the controller detects that the rotation speed of each Mecanum wheel does not meet the set rotation speed control requirement, that is, controls each servo driver to generate a current signal of different magnitude to the corresponding drive motor to generate different driving forces to ensure that each Mecanum wheel can still rotate at the set speed; at the same time, the controller samples the output current signal;

[0013] S3, the controller calculates the current center of mass position of the Mecanum wheel mobile platform according to all sampled current signals and based on the relationship between the current and the load of the drive motor;

[0014] S4, the controller calculates the displacement of the counterweight blocks on each counterweight adjustment mechanism according to the current center of mass position, with the goal of balancing the center of mass position of the entire Mecanum wheel mobile platform, and ensures that the counterweight blocks on each counterweight adjustment mechanism do not exceed the maximum displacement range;

[0015] S5, the controller converts the calculated displacement of the counterweight blocks on each counterweight adjustment mechanism into the control steps of the counterweight motors on each counterweight adjustment mechanism, and controls the corresponding configuration motors to work, driving each counterweight block to move to a set position;

[0016] S6, the controller updates the center of mass position and calculates and adjusts the output current value in real time according to the updated center of mass position, and then outputs the corresponding current signal to the drive motor through the servo driver to drive each Mecanum wheel to rotate;

[0017] S7, the controller detects whether the rotation speed of each Mecanum wheel meets the set rotation speed control requirement, and if so, completes an adaptive center of mass balance, otherwise returns to step S2, controls each servo driver to generate current signals of different sizes to the corresponding drive motor to generate different driving forces, and samples the current signal at the same time, and continues to execute steps S3-S6 until the center of mass balance of the Mecanum wheel mobile platform is achieved.

[0018] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a Mecanum wheel mobile platform with adaptively balanced center of mass, which solves the balance problem during the movement of the platform. Compared with the prior art, it has higher stability, stronger adaptability and better energy efficiency performance, and provides a new implementation solution for the development of omnidirectional mobile platforms. It has strong practicality and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a stereoscopic diagram of a Mecanum wheel mobile platform according to an embodiment of the present invention;

[0020] Figure 2 is a top view of a Mecanum wheel mobile platform according to an embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the structure of a Mecanum wheel mechanism in an embodiment of the present invention (the servo drive is not shown);

[0022] Figure 4 is a side view of a counterweight adjustment mechanism in an embodiment of the present invention;

[0023] Figure 5 is a top view of the counterweight adjustment mechanism in an embodiment of the present invention (the base is not shown);

[0024] Figure 6 is a schematic diagram of the working state of each counterweight adjustment mechanism before the center of mass position is adjusted in an embodiment of the present invention;

[0025] Figure 7 It is a schematic diagram of the working status of each counterweight adjustment mechanism after the center of mass position is adjusted in an embodiment of the present invention.

[0026] In the figure: 1-driving motor; 2-first coupling; 3-reducer; 4-Mecanum wheel; 100-Mecanum wheel mechanism; 200-carrying platform; 300-counterweight adjustment mechanism; 301-counterweight motor; 302-second coupling; 303-screw; 304-counterweight block; 400-controller. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] like Figure 1-2As shown, the present embodiment provides a Mecanum wheel mobile platform capable of adaptively balancing the center of mass, comprising a carrying platform 200, a Mecanum wheel train, a counterweight adjustment system and a controller 400, wherein the Mecanum wheel train comprises a plurality of Mecanum wheel mechanisms 100, wherein the plurality of Mecanum wheel mechanisms 100 are symmetrically mounted below the carrying platform 200, the counterweight adjustment system comprises a plurality of counterweight adjustment mechanisms 300 equal in number to the number of the Mecanum wheel mechanisms, wherein the plurality of counterweight adjustment mechanisms 300 are evenly mounted above the carrying platform 200, the controller 400 is disposed on the carrying platform 200 and is electrically connected to each Mecanum wheel mechanism 100 and the counterweight adjustment mechanism 300, respectively, so as to dynamically adjust the rotation speed of each Mecanum wheel by controlling the current output, and at the same time, control each counterweight adjustment mechanism to adjust the position of the counterweight block thereon on the carrying platform according to the current signal, so as to adaptively balance the center of mass of the entire Mecanum wheel mobile platform.

[0031] like Figure 3 As shown, the Mecanum wheel mechanism includes a servo driver, a drive motor 1, a first coupling 2, a reducer 3 and a Mecanum wheel 4. The servo driver and the drive motor 1 are installed below the carrier platform 200 via a suspension mechanism. The output shaft of the drive motor is connected to the reducer 3 via the first coupling 2, and the reducer 3 is connected to the Mecanum wheel 4 to drive the Mecanum wheel to rotate. The controller is electrically connected to the drive motor through the servo driver to adjust the current value in real time according to the speed control requirement of the Mecanum wheel, output a corresponding current signal to the drive motor to control its rotation, and sample the output current signal at the same time.

[0032] In this embodiment, if Figure 4-5 As shown, the counterweight adjustment mechanism includes a base, a slide rail, a counterweight motor 301, a second coupling 302, a screw 303 and a counterweight block 304. The base is fixedly installed above the supporting platform 200, the counterweight motor 301 is fixedly installed on the supporting platform 200, and its output shaft is fixedly connected to the horizontally arranged screw 303 via the second coupling 302 to drive the screw 303 to rotate, the slide rail is arranged parallel to the screw 303 and fixedly connected to the supporting platform 200, the counterweight block 304 is spirally matched with the screw 303 and slidingly matched with the slide rail, thereby converting the rotational motion of the screw into the horizontal linear motion of the counterweight block; the controller 400 is electrically connected to the counterweight motor 301 to control the rotation of the counterweight motor, thereby changing the position of the counterweight block on the supporting platform.

[0033] In this embodiment, the counterweight adjustment mechanism includes two slide rails, which are arranged in parallel on the left and right sides of the screw rod and fixedly connected to the bearing platform, and the counterweight block slides with the two slide rails at the same time; the counterweight adjustment mechanism also includes two bearing seats, which are fixedly installed on the front and rear sides of the base respectively, and the front and rear ends of the screw rod are rotatably connected to the base via the bearing seats respectively, and the front and rear ends of the two slide rails are fixedly connected to the bearing seats respectively.

[0034] According to different load requirements and precision requirements, the present invention can freely select different types of counterweight adjustment mechanisms. If high precision and large thrust are required, a screw drive module can be used, which can provide higher precision and greater load capacity. For application scenarios that require higher speed but do not require precise positioning and thrust, a synchronous belt drive module can be selected, which is more suitable for high-speed transmission and has lower precision requirements. Depending on the use environment, the system can adapt to different types of linear slide modules. When there is a lot of dust in the environment, a closed linear slide module should be selected to prevent the dust from affecting the transmission system; in a dust-free environment, an open linear slide module can be selected to reduce costs and improve transmission efficiency. For maintainability and high load requirements, when selecting a linear slide module, it is recommended to use a linear rail type linear slide module under high load conditions to enhance its load-bearing capacity and stability; when the load is light, an optical axis type linear slide module can be selected, which has a simple structure and is easy to maintain. Through these reasonable selections and combinations, the efficient operation and reliability of the entire counterweight adjustment system under different working conditions can be ensured.

[0035] In this embodiment, the Mecanum wheel system includes four Mecanum wheel mechanisms, which are symmetrically arranged in pairs and distributed at the left front, right front, left rear and right rear positions below the load-bearing platform; the counterweight adjustment system includes four counterweight adjustment mechanisms, which are correspondingly arranged on the load-bearing platform above the corresponding Mecanum wheel mechanisms, and the center of each counterweight adjustment mechanism is vertically coincident with the center of the corresponding Mecanum wheel, and one end of each counterweight adjustment mechanism is oriented toward the geometric center of the mobile platform, so as to position each counterweight adjustment mechanism. The counterweight motor on the Mecanum wheel mechanism is installed at one end close to the geometric center of the mobile platform.

[0036] The control logic of the Mecanum wheel mobile platform during operation is as follows:

[0037] S1. When the Mecanum wheel mobile platform starts working, the system is initialized first; then, the controller outputs corresponding current signals to the drive motors through the servo drivers according to the speed control requirements, so as to drive each Mecanum wheel to rotate at a set speed;

[0038] S2. When the Mecanum wheel mobile platform is unevenly loaded, the controller detects that the rotation speed of each Mecanum wheel does not meet the set rotation speed control requirement, that is, controls each servo driver to generate a current signal of different magnitude to the corresponding drive motor to generate different driving forces to ensure that each Mecanum wheel can still rotate at the set speed; at the same time, the controller samples the output current signal;

[0039] S3, the controller calculates the current center of mass position of the Mecanum wheel mobile platform according to all sampled current signals and based on the relationship between the current and the load of the drive motor;

[0040] S4, the controller calculates the displacement of the counterweight blocks on each counterweight adjustment mechanism according to the current center of mass position, with the goal of balancing the center of mass position of the entire Mecanum wheel mobile platform, and ensures that the counterweight blocks on each counterweight adjustment mechanism do not exceed the maximum displacement range;

[0041] S5, the controller converts the calculated displacement of the counterweight blocks on each counterweight adjustment mechanism into the control steps of the counterweight motors on each counterweight adjustment mechanism, and controls the corresponding configuration motors to work, driving each counterweight block to move to a set position;

[0042] S6, the controller updates the center of mass position and calculates and adjusts the output current value in real time according to the updated center of mass position, and then outputs the corresponding current signal to the drive motor through the servo driver to drive each Mecanum wheel to rotate;

[0043] S7, the controller detects whether the rotation speed of each Mecanum wheel meets the set rotation speed control requirement, and if so, completes an adaptive center of mass balance, otherwise returns to step S2, controls each servo driver to generate current signals of different sizes to the corresponding drive motor to generate different driving forces, and samples the current signal at the same time, and continues to execute steps S3-S6 until the center of mass balance of the Mecanum wheel mobile platform is achieved.

[0044] Due to different loads, the driving motor overcomes different ground friction forces, resulting in different rotation currents of the four Mecanum wheels. The relationship between the current and load of the driving motor is described in detail as follows.

[0045] In this embodiment, the driving motor is a DC motor, and the basic equation of the DC motor includes:

[0046] Voltage equation: U = IR arm +K e ω

[0047] Torque equation: M motor =K t I

[0048] Among them, U is the motor voltage, I is the motor current, R arm is the armature resistance, K e is the back electromotive force constant, ω is the motor speed, M motor is the motor output torque, K t is the torque constant; the motor output power is calculated through the motor efficiency η motor Converted into output mechanical power P mesh =η motor ·U·I, the motor output torque is amplified to M after being decelerated by the reducer output =M motor ·n·η gear , where n is the reduction ratio, η gear is the reducer efficiency.

[0049] The friction torque of the Mecanum wheel is determined by the friction coefficient μ and the load F. n and wheel radius R, its friction torque M friction =μF n R; output torque M after the reducer is decelerated output is equal to the friction torque of the Mecanum wheel motion, so there exists M motor ·n·η gear =μF n R; Combined with the motor torque equation, the relationship between current and load is solved as follows:

[0050]

[0051] Further considering the motor efficiency η motor , the relationship between current and load is:

[0052]

[0053] This formula is valid for conditions where the critical load is not exceeded.

[0054] When the load is less than the critical load, the current and load satisfy the above equation and the speed decreases linearly with the increase of load; when the load is equal to the critical load, the speed is When the load is greater than the critical load, stalling may occur and the motor is prone to accidents.

[0055] According to the relationship between current and load, the current center of mass position of the Mecanum wheel mobile platform can be calculated from the current values ​​of the four Mecanum wheels. The specific instructions are as follows.

[0056] The four Mecanum wheels are symmetrically distributed in a rectangular shape, with a wheelbase of 2a and a wheelbase of 2b. The coordinate system is established with the geometric center of the mobile platform as the coordinate origin; the position coordinates of the four Mecanum wheels are respectively expressed as: wheel 1 (a1, b1), wheel 2 (a2, b2), wheel 3 (a3, b3), wheel 4 (a4, b4), where (a1, b1) = (a, b), (a2, b2) = (-a, b), (a3, b3) = (-a, -b), (a4, b4) = (a, -b). The vertical force balance equation, the moment balance equation around the x-axis, and the moment balance equation around the y-axis in the static equilibrium equation are established as follows:

[0057]

[0058] The relationship between current and load can be obtained by combining the coordinates (x, y) of the center of mass position:

[0059]

[0060] Among them, F n1 、F n2 、F n3 、F n4 are the single wheel load capacities of the four Mecanum wheels, F n1 +F n2 +F n3 +F n4 =F n , I1, I2, I3, and I4 represent the driving motor currents of the four Mecanum wheels respectively.

[0061] Based on the calculated current center of mass position, the displacement of the counterweight blocks on each counterweight adjustment mechanism is calculated, and different priorities are assigned to different counterweight adjustment mechanisms, and different control signals are output to the corresponding counterweight motors to make them work and drive the counterweight blocks to move on the bearing platform, thereby changing the center of mass position;

[0062] Assume the mass of the counterweight is m and the moving distance of the counterweight is s. i , where s i It represents the displacement of the counterweight block along the horizontal line connecting the center of the counterweight adjustment mechanism and the geometric center of the mobile platform with the center of the counterweight adjustment mechanism as the origin (unit vector in Movement toward the geometric center of the mobile platform is negative, and movement in the opposite direction is positive, i = 1, 2, 3, 4, and the movement of the four counterweights does not interfere with each other. The maximum displacement distance of the counterweight is s max , that is, the displacement range of the counterweight is [-s max ,s max ].

[0063] The goal of center of mass balance is to adjust s1, s2, s3, and s4 so that the center of mass of the Mecanum wheel mobile platform returns from the current center of mass position (x, y) to the geometric center of the mobile platform (0, 0).

[0064] The key point of the above mobile counterweight principle is to use the center of mass balance equation. Assume that the current center of mass position is (x, y), and the mass of the Mecanum wheel mobile platform minus the counterweight is M, which satisfies the center of mass equation:

[0065]

[0066] According to the positions and center of mass equations of the four counterweight blocks, the counterweight displacement equations are obtained:

[0067]

[0068] The counterweight displacement is obtained by the minimum norm solution:

[0069]

[0070] According to the counterweight displacement equation group, the dynamic regression equation of the platform center of mass can be obtained:

[0071]

[0072] When x=0,y=0,s i =0, the counterweight does not move; when x>0, the right counterweight (s1, s4>0) moves inwards, and the left counterweight (s2, s3>0) moves outwards; the calibration coefficient can be adjusted according to the actual operating conditions to adapt the system.

[0073] The counterweight displacement can adopt an optimal algorithm (designed separately and not within the scope of protection of the present invention) to mobilize the four mobile counterweights to move appropriately, so as to improve the movement efficiency and reduce the impact caused by the movement of the counterweight.

[0074] According to the calculated moving distance of the counterweight block, the counterweight motor rotates to drive the screw to rotate so that the counterweight block moves; assuming that the lead of the screw is P, the step angle of the drive motor is α, and the microstep subdivision multiple of the servo driver is N, the rotation angle of the drive motor is obtained as The control steps of the servo drive are

[0075] Figure 6 , 7 It is a schematic diagram of the working status of each counterweight adjustment mechanism before and after the center of mass position is adjusted in this embodiment.

[0076] The Mecanum wheel mobile platform proposed in the present invention is not limited to a four-wheel Mecanum wheel system, and can also be a Mecanum wheel system including six Mecanum wheel mechanisms or eight Mecanum wheel mechanisms that can realize omnidirectional movement. The counterweight adjustment system is configured with a plurality of counterweight adjustment mechanisms equal in number to the number of Mecanum wheel mechanisms. The plurality of counterweight adjustment mechanisms are correspondingly arranged on the bearing platform above the corresponding Mecanum wheel mechanisms. The center of each counterweight adjustment mechanism coincides with the center of the corresponding Mecanum wheel in the vertical direction, and one end of each counterweight adjustment mechanism faces the geometric center of the mobile platform, so as to position each counterweight adjustment mechanism.

[0077] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A Mecanum wheel mobile platform capable of adaptively balancing the center of mass, characterized in that: The invention comprises a load-bearing platform, a Mecanum wheel system, a counterweight adjustment system and a controller. The Mecanum wheel system comprises a plurality of Mecanum wheel mechanisms, which are symmetrically installed below the load-bearing platform. The counterweight adjustment system comprises a plurality of counterweight adjustment mechanisms whose number is equal to that of the Mecanum wheel mechanisms, which are evenly installed above the load-bearing platform. The controller is disposed on the load-bearing platform and is electrically connected to each Mecanum wheel mechanism and the counterweight adjustment mechanism, respectively, so as to dynamically adjust the rotation speed of each Mecanum wheel by controlling the current output, and at the same time, controls each counterweight adjustment mechanism to adjust the position of the counterweight block thereon on the load-bearing platform according to the current signal, so as to adaptively balance the center of mass of the entire Mecanum wheel mobile platform.

2. The Mecanum wheel mobile platform capable of adaptively balancing the center of mass according to claim 1, characterized in that: The Mecanum wheel mechanism includes a servo driver, a drive motor, a first coupling, a reducer and a Mecanum wheel. The servo driver and the drive motor are installed below the load-bearing platform via a suspension mechanism. The output shaft of the drive motor is connected to the reducer via the first coupling. The reducer is connected to the Mecanum wheel to drive the Mecanum wheel to rotate. The controller is electrically connected to the drive motor through a servo driver to adjust the current value in real time according to the speed control requirements of the Mecanum wheel, output a corresponding current signal to the drive motor to control its rotation, and simultaneously sample the output current signal.

3. The Mecanum wheel mobile platform capable of adaptively balancing the center of mass according to claim 1, characterized in that: The counterweight adjustment mechanism includes a base, a slide rail, a counterweight motor, a second coupling, a screw and a counterweight block. The base is fixedly installed above the load-bearing platform, the counterweight motor is fixedly installed on the load-bearing platform, and its output shaft is fixedly connected to the horizontally arranged screw via the second coupling to drive the screw to rotate. The slide rail is arranged parallel to the screw and is fixedly connected to the load-bearing platform. The counterweight block is spirally matched with the screw and slidingly matched with the slide rail, thereby converting the rotational motion of the screw into horizontal linear motion of the counterweight block; the controller is electrically connected to the counterweight motor to control the rotation of the counterweight motor, thereby changing the position of the counterweight block on the load-bearing platform.

4. The Mecanum wheel mobile platform capable of adaptively balancing the center of mass according to claim 3, characterized in that: The counterweight adjustment mechanism includes two slide rails, which are arranged in parallel on the left and right sides of the screw rod and fixedly connected to the bearing platform, and the counterweight block slides with the two slide rails at the same time; the counterweight adjustment mechanism also includes two bearing seats, which are fixedly installed on the front and rear sides of the base respectively, and the front and rear ends of the screw rod are rotatably connected to the base via the bearing seats respectively, and the front and rear ends of the two slide rails are fixedly connected to the bearing seats respectively.

5. The Mecanum wheel mobile platform capable of adaptively balancing the center of mass according to claim 1, characterized in that: The Mecanum wheel system includes four Mecanum wheel mechanisms, which are symmetrically arranged in pairs and distributed at the left front, right front, left rear and right rear positions below the load-bearing platform; the counterweight adjustment system includes four counterweight adjustment mechanisms, which are correspondingly arranged on the load-bearing platform above the corresponding Mecanum wheel mechanisms, the center of each counterweight adjustment mechanism vertically coincides with the center of the corresponding Mecanum wheel, and one end of each counterweight adjustment mechanism faces the geometric center of the mobile platform, so as to position each counterweight adjustment mechanism.

6. The Mecanum wheel mobile platform capable of adaptively balancing the center of mass according to claim 5, characterized in that: The counterweight motor on the Mecanum wheel mechanism is installed at one end close to the geometric center of the mobile platform.

7. The Mecanum wheel mobile platform capable of adaptively balancing the center of mass according to claim 5, characterized in that: The control logic of the Mecanum wheel mobile platform during operation is as follows: S1. When the Mecanum wheel mobile platform starts working, the system is initialized first; then, the controller outputs corresponding current signals to the drive motors through the servo drivers according to the speed control requirements, so as to drive each Mecanum wheel to rotate at a set speed; S2. When the Mecanum wheel mobile platform is unevenly loaded, the controller detects that the rotation speed of each Mecanum wheel does not meet the set rotation speed control requirement, that is, controls each servo driver to generate a current signal of different magnitude to the corresponding drive motor to generate different driving forces to ensure that each Mecanum wheel can still rotate at the set speed; at the same time, the controller samples the output current signal; S3, the controller calculates the current center of mass position of the Mecanum wheel mobile platform according to all sampled current signals and based on the relationship between the current and the load of the drive motor; S4, the controller calculates the displacement of the counterweight blocks on each counterweight adjustment mechanism according to the current center of mass position, with the goal of balancing the center of mass position of the entire Mecanum wheel mobile platform, and ensures that the counterweight blocks on each counterweight adjustment mechanism do not exceed the maximum displacement range; S5, the controller converts the calculated displacement of the counterweight blocks on each counterweight adjustment mechanism into the control steps of the counterweight motors on each counterweight adjustment mechanism, and controls the corresponding configuration motors to work, driving each counterweight block to move to a set position; S6, the controller updates the center of mass position and calculates and adjusts the output current value in real time according to the updated center of mass position, and then outputs the corresponding current signal to the drive motor through the servo driver to drive each Mecanum wheel to rotate; S7, the controller detects whether the rotation speed of each Mecanum wheel meets the set rotation speed control requirement, and if so, completes an adaptive center of mass balance, otherwise returns to step S2, controls each servo driver to generate current signals of different sizes to the corresponding drive motor to generate different driving forces, and samples the current signal at the same time, and continues to execute steps S3-S6 until the center of mass balance of the Mecanum wheel mobile platform is achieved.

8. The Mecanum wheel mobile platform capable of adaptively balancing the center of mass according to claim 7, characterized in that: The current and load of the driving motor have the following relationship: The driving motor is a DC motor, and the basic equation of the DC motor includes: Voltage equation: U = IR arm +K e ω Torque equation: M motor =K t I Among them, U is the motor voltage, I is the motor current, R arm is the armature resistance, K e is the back electromotive force constant, ω is the motor speed, M motor is the motor output torque, K t is the torque constant; the motor output power is calculated through the motor efficiency η motor Converted into output mechanical power P mesh =η motor ·U·I, the motor output torque is amplified to M after being decelerated by the reducer output =M motor ·n·η gear , where n is the reduction ratio, η gear is the reducer efficiency; The friction torque of the Mecanum wheel is determined by the friction coefficient μ and the load F. n and wheel radius R, its friction torque M friction =μF n R; output torque M after the reducer is decelerated output is equal to the friction torque of the Mecanum wheel motion, so there exists M motor ·n·η gear =μF n R; Combined with the motor torque equation, the relationship between current and load is solved as follows: Further considering the motor efficiency η motor , the relationship between current and load is: When the load is less than the critical load, the current and load satisfy the above equation and the speed decreases linearly with the increase of load; when the load is equal to the critical load, the speed is When the load is greater than the critical load, the motor will be blocked and an accident may occur; According to the relationship between current and load, the current center of mass position of the Mecanum wheel mobile platform is calculated from the current values ​​of the four Mecanum wheels; specifically: The four Mecanum wheels are symmetrically distributed in a rectangular shape, with a wheelbase of 2a and a wheelbase of 2b. The coordinate system is established with the geometric center of the mobile platform as the coordinate origin; the position coordinates of the four Mecanum wheels are expressed as: (a1, b1), (a2, b2), (a3, b3), (a4, b4), where (a1, b1) = (a, b), (a2, b2) = (-a, b), (a3, b3) = (-a, -b), (a4, b4) = (a, -b); the vertical force balance equation, the moment balance equation around the x-axis, and the moment balance equation around the y-axis in the static equilibrium equation are established as follows: The relationship between current and load can be obtained by combining the coordinates (x, y) of the center of mass position: Among them, F n1 、F n2 、F n3 、F n4 are the single wheel load capacities of the four Mecanum wheels, F n1 +F n2 +F n3 +F n4 =F n , I1, I2, I3, and I4 represent the driving motor currents of the four Mecanum wheels respectively.

9. The Mecanum wheel mobile platform capable of adaptively balancing the center of mass according to claim 8, characterized in that: Based on the calculated current center of mass position, the displacement of the counterweight blocks on each counterweight adjustment mechanism is calculated, and different priorities are assigned to different counterweight adjustment mechanisms, and different control signals are output to the corresponding counterweight motors to make them work and drive the counterweight blocks to move on the bearing platform, thereby changing the center of mass position; Assume the mass of the counterweight is m and the moving distance of the counterweight is s. i , where s i It represents the displacement of the counterweight block along the horizontal line connecting the center of the counterweight adjustment mechanism and the geometric center of the mobile platform with the center of the counterweight adjustment mechanism as the origin. Movement toward the geometric center of the mobile platform is negative, and movement in the opposite direction is positive. i=1,2,3,4, and the movements of the four counterweight blocks do not interfere with each other. The maximum displacement distance of the counterweight block is s max , that is, the displacement range of the counterweight is [-s max ,s max ]; The goal of center of mass balance is to adjust s1, s2, s3, and s4 so that the center of mass of the Mecanum wheel mobile platform returns from the current center of mass position (x, y) to the geometric center of the mobile platform (0, 0); Assume that the current center of mass position is (x, y), and the mass of the Mecanum wheel mobile platform minus the counterweight is M, which satisfies the center of mass equation: According to the positions of the four counterweight blocks and the center of mass equation, the counterweight displacement equation group is obtained: The counterweight displacement is obtained by the minimum norm solution: According to the counterweight displacement equation group, the dynamic regression equation of the platform center of mass can be obtained: According to the calculated moving distance of the counterweight block, the counterweight motor rotates to drive the screw to rotate so that the counterweight block moves; assuming that the lead of the screw is P, the step angle of the drive motor is α, and the microstep subdivision multiple of the servo driver is N, the rotation angle of the drive motor is obtained as The control steps of the servo drive are 10. The Mecanum wheel mobile platform capable of adaptively balancing the center of mass according to claim 1, characterized in that: The Mecanum wheel train is a Mecanum wheel train that can realize omnidirectional movement and includes 6 Mecanum wheel mechanisms or 8 Mecanum wheel mechanisms. The counterweight adjustment system is configured with a plurality of counterweight adjustment mechanisms whose number is equal to that of the Mecanum wheel mechanisms. The plurality of counterweight adjustment mechanisms are correspondingly arranged on the bearing platform above the corresponding Mecanum wheel mechanisms. The center of each counterweight adjustment mechanism is vertically coincident with the center of the corresponding Mecanum wheel, and one end of each counterweight adjustment mechanism faces the geometric center of the mobile platform, so as to position each counterweight adjustment mechanism.

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