Self-adaptive gravity center adjusting two-wheeled vehicle balance control method and system

Abstract

The invention relates to a self-adaptive gravity center adjusting two-wheeled vehicle balance control method and system, and the method comprises the steps that an active gravity center control unit is arranged on a two-wheeled vehicle, and the active gravity center control unit comprises a counterweight structure and an adjusting motor for driving the counterweight structure to rotate; the control method comprises the steps of constructing an affine nonlinear dynamic model based on the two-wheeled vehicle and the counterweight structure, establishing a self-adaptive sliding mode controller based on the affine nonlinear dynamic model and disturbance, and solving the affine nonlinear dynamic model through the self-adaptive sliding mode controller so as to output an input torque for driving the counterweight structure. The adjusting motor drives the balance weight structure to incline by a certain angle based on the input torque so as to generate aligning torque to enable the two-wheeled vehicle to recover the balance state. The gravity center of the two-wheeled vehicle is automatically adjusted according to the change of the roll angle of the vehicle body of the two-wheeled vehicle by utilizing the weight of the two-wheeled vehicle, so that the self-balance of the two-wheeled vehicle under the static and interference conditions is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of two-wheeled vehicle control, and specifically to an adaptive center-of-gravity adjustment two-wheeled vehicle balance control method and system. Background Art

[0002] Two-wheeled robots have the advantages of simple structure, small turning radius, flexible driving, and low energy consumption, and have been widely studied. A two-wheeled vehicle is a typical two-wheeled robot and has natural operation advantages in narrow spaces such as jungles, mountains, and streets; driverless two-wheeled vehicles can not only be applied to automated operations such as express delivery, transportation, and urban patrol in cities, but also be used for intelligent operations such as dangerous rescue, field patrol, surveillance, and data collection in the wild.

[0003] A non-coaxial two-wheeled vehicle itself is a non-holonomic constraint system, with characteristics such as non-linearity, under-actuation, and strong coupling. It has lateral instability and is difficult to maintain stability in an operating environment with large terrain fluctuations such as mountains, deserts, and jungles. When disturbed, it is difficult to maintain balance only relying on the front fork system and its own inertia, and it is easy to lose balance and tip over.

[0004] Most current traditional structural designs use a momentum wheel or a control moment gyroscope to provide a lateral restoring moment, or balance through the inertial moment generated by the first wheel's steering and speed. The momentum wheel only generates a restoring moment during acceleration and deceleration, and the vibration generated during its high-speed rotation is large, which is likely to cause system instability; relying on a moment gyroscope for balance requires maintaining the high-speed rotation of the gyroscope, which not only consumes a large amount of energy but also has poor safety; the method relying only on the first wheel's steering is difficult to maintain balance at rest and low speeds; current control algorithms such as the proportional integral derivative control method and the linear quadratic regulator control method have poor control effects and poor robustness, and are prone to rollover in an unstructured environment and undulating terrain, and the balance ability is limited. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the purpose of the present invention is to provide an adaptive center-of-gravity adjustment two-wheeled vehicle balance control method and system, configured with an adaptive sliding mode controller, which uses the own weight of the two-wheeled vehicle to autonomously adjust the center of gravity of the two-wheeled vehicle according to the change of the inclination angle of the two-wheeled vehicle, and realizes the self-balancing of the two-wheeled vehicle under static and disturbed conditions.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows: An adaptive center-of-gravity adjustment two-wheeled vehicle balance control method, comprising: A passive center-of-gravity control unit is arranged on the two-wheeled vehicle, and the passive center-of-gravity control unit includes a counterweight structure and an adjustment motor for driving the counterweight structure to tilt; Construct an affine nonlinear dynamic model based on the two-wheeled vehicle and the counterweight structure; An adaptive sliding mode controller is established based on an affine nonlinear dynamic model and perturbations. The affine nonlinear dynamic model is solved by the adaptive sliding mode controller to output the input torque of the counterweight structure. The adjustment motor drives the counterweight structure to tilt at a certain angle based on the input torque, so as to generate a restoring torque to make the two-wheeled vehicle return to the balanced state.

[0007] Furthermore, the affine nonlinear dynamic model is:

[0008]

[0009]

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

[0016] Among them, respectively represent the masses of the two-wheeled vehicle and the counterweight structure, respectively represent the lengths of the two-wheeled vehicle and the counterweight structure, represents the distance from the two-wheeled vehicle to the underactuated joint, represents the distance from the center of gravity of the counterweight structure to the driving joint, respectively represent the moments of inertia of the two-wheeled vehicle and the counterweight structure, is the acceleration due to gravity, is the roll angle of the two-wheeled vehicle, is the angle of rotation of the counterweight structure relative to the two-wheeled vehicle, is the output torque of the adjustment motor, is the model uncertainty perturbation, is the external perturbation, represents the roll angle of the two-wheeled vehicle of the equivalent inertia term, represents the roll angle of the two-wheeled vehicle and the angle of rotation of the counterweight structure relative to the two-wheeled vehicle between the inertial coupling term, represents the angle of rotation of the counterweight structure relative to the two-wheeled vehicle of the equivalent inertia term, is the roll angle of the two-wheeled vehicle The gravitational moment of is the angle at which the counterweight structure rotates relative to the two-wheeler The gravitational moment of is the Coriolis force and centrifugal force terms of the vehicle body, is the Coriolis force and centrifugal force terms of the counterweight structure, is the roll angular velocity of the vehicle body, is the angular velocity of the counterweight structure, is the roll angular acceleration of the vehicle body, is the angular acceleration of the counterweight structure, , , are function intermediate variables respectively.

[0017] Furthermore, the perturbation includes model uncertainty and external perturbation, where the absolute value of the model uncertainty is less than or equal to the model uncertainty threshold, and the absolute value of the external perturbation is less than or equal to the external perturbation threshold.

[0018] Furthermore, the method for establishing the adaptive sliding mode controller is as follows: Perform a global coordinate transformation to transform the original state system corresponding to the affine nonlinear dynamic model into a new cascaded form system through a diffeomorphism transformation, and obtain the dynamic equation of the new cascaded form system; Design a balance controller for the dynamic equation of the new cascaded form system, set the sliding mode surface, and establish an adaptive sliding mode controller based on the balance controller.

[0019] Furthermore, the method for performing a global coordinate transformation to transform the original state system corresponding to the affine nonlinear dynamic model into a new system state and establishing the dynamic equation of the new cascaded form system is as follows: Obtain the new system state, specifically:

[0020]

[0021]

[0022]

[0023] Among them, is the original system state, is the state of the new cascaded form system, is the coupling state, is the generalized momentum, and are the angle and velocity of the counterweight structure respectively, is the core transformation function, is the Lagrangian function, which is used to describe the energy characteristics of the system and obtain the dynamic characteristics of the system through partial derivative operations; Obtain the dynamic equation of the new cascaded form system, specifically:

[0024] where, represents the negative value of the gravitational torque of the generalized momentum , represents the velocity of the counterweight structure of the comprehensive dynamic coupling term, is the total disturbance that couples the model uncertainty disturbance and the external disturbance;

[0025] where, is the equivalent mass coupling term.

[0026] Furthermore, design a balance controller for the dynamic equation of the new cascaded form system. The method of setting the sliding mode surface and establishing an adaptive sliding mode controller based on the balance controller is specifically as follows: The balance controller is represented by the equilibrium point, specifically

[0027] Then the equilibrium point of the new system state after the diffeomorphism mapping is:

[0028] The new system dynamic equation satisfies is reversible, and is bounded; Design the sliding mode hyperplane:

[0029]

[0030] where, represents the deviation between the current roll state of the two-wheeled vehicle and the vertical position, represents the deviation of the dynamic characteristics of the current roll direction of the two-wheeled vehicle, represents the nonlinear characteristics of represents the dynamic change rate of, are respectively the weight coefficients in the sliding mode hyperplane; According to the design method of the sliding mode controller for the underactuated system, design the sliding mode controller. The input torque of the system is:

[0031]

[0032] Among them, for feedforward compensation based on the model, used to cancel the error caused by model uncertainty and external disturbance, is a constant, representing the model uncertainty disturbance of the maximum amplitude, representing the external disturbance or the maximum amplitude of the coupling disturbance, is the sliding mode gain, is the sliding mode surface.

[0033] An adaptive center-of-gravity adjustment two-wheeler balance control system, comprising: A two-wheeler balance module, used to set an active center-of-gravity control unit on the two-wheeler, and the active center-of-gravity control unit includes a counterweight structure and an adjustment motor for driving the counterweight structure to tilt; An affine nonlinear dynamics model module, used to construct an affine nonlinear dynamics model based on the two-wheeler and the counterweight structure; An adaptive sliding mode controller module, used to establish an adaptive sliding mode controller based on the affine nonlinear dynamics model and the disturbance, and solve the affine nonlinear dynamics model through the adaptive sliding mode controller to output the input torque of the counterweight structure; An adjustment module, used to adjust the motor to drive the counterweight structure to tilt a certain angle based on the input torque, so as to generate a restoring torque to make the two-wheeler return to the balanced state.

[0034] Further, in the two-wheeler balance module, the two-wheeler includes a first wheel, a second wheel and a vehicle body, the first wheel is arranged on the front side of the vehicle body, the second wheel is arranged on the rear side of the vehicle body, the first wheel steers through a first driving mechanism, the second wheel goes straight through a second driving mechanism, and the counterweight structure and the adjustment motor are arranged on the vehicle body and between the first wheel and the second wheel; The affine nonlinear dynamics model module is used to construct an affine nonlinear dynamics model based on the vehicle body and the counterweight structure.

[0035] An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, it implements the above-mentioned adaptive center-of-gravity adjustment two-wheeler balance control method.

[0036] Further, the processor selects an STM32 main control board, which is equipped with an IMU sensor for two-wheeler attitude recognition. The IMU sensor communicates with the STM32 main control board through the USART serial port, and the STM32 main control board sends control signals to the adjustment motor of the active center-of-gravity control unit and the two-wheeler.

[0037] A non-transitory computer-readable storage medium stores a computer program thereon, and when the computer program is executed by a processor, it implements the adaptive center-of-gravity adjustment two-wheeled vehicle balance control method as described above.

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects: The adaptive center-of-gravity adjustment two-wheeled vehicle balance control method provided by the present invention adopts an active center-of-gravity adjustment technology, realizes dynamic adjustment of the center-of-gravity position through its own weight, can automatically adjust the center-of-gravity according to the inclination state of the vehicle body, generates a restoring moment, and keeps the vehicle body always balanced. Compared with the traditional passive balance method, the active center-of-gravity adjustment technology of the present invention can significantly improve the self-balancing ability of the two-wheeled vehicle, adapt to more complex terrains, and has no additional weight, strong robustness, and high energy utilization rate.

[0039] The adaptive center-of-gravity adjustment two-wheeled vehicle balance control method provided by the present invention can adjust control parameters in real time according to different working conditions, and has strong robustness to model uncertainties and external disturbances. Traditional methods such as PID control and LQR control are difficult to adapt to the strongly non-linear and strongly coupled two-wheeled vehicle system, while sliding mode control can effectively suppress the influence of model uncertainties and external disturbances by introducing a sliding mode surface and constraining the trajectory of the system near the sliding mode surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings described herein are used to provide a further understanding of the present invention and form a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 is a flowchart of an adaptive center-of-gravity adjustment two-wheeled vehicle balance control method of the present invention; Figure 2 is a control principle diagram of an adaptive center-of-gravity adjustment two-wheeled vehicle balance control method of the present invention; FIG. 3(a) is the result of the roll angle change data of the two-wheeled vehicle righting experiment of the present invention; FIG. 3(b) is the result of the rotation angle change data of the active center-of-gravity adjustment unit of the two-wheeled vehicle righting experiment of the present invention; FIG. 4(a) is the result of the roll angle change data of the two-wheeled vehicle cross-country experiment of the present invention; FIG. 4(b) is the result of the rotation angle change data of the active center-of-gravity adjustment unit of the two-wheeled vehicle cross-country experiment of the present invention; Figure 5 is a schematic diagram of an adaptive center-of-gravity adjustment two-wheeled vehicle balance control system of the present invention; Figure 6 is a schematic diagram of the two-wheeled vehicle of the present invention; Figure 7 is a schematic diagram of the balanced state of the two-wheeled vehicle of the present invention; Figure 8 Schematic diagram for the balance restoration of the two - wheel vehicle of the present invention in the first - direction tilt state; Figure 9 Schematic diagram for the balance restoration of the two - wheel vehicle of the present invention in the second - direction tilt state.

[0041] Wherein, 1, vehicle body; 2, counterweight structure; 3, first wheel; 4, second wheel; 5, synchronous belt; 6, main control board; 7, steering servo; 8, brushless motor; 9, first driving wheel; 10, second driving wheel; 11, front fork; 12, battery; 13, attitude sensor; 14, adjustment motor. Specific embodiments

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0043] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are 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 orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0044] Embodiment 1 Embodiment 1 provides an adaptive center - of - gravity adjustment two - wheel vehicle balance control method, as shown in Figure 1 , Figure 2 and Figure 6 shown, including: Step S1: Set an active center - of - gravity control unit on the two - wheel vehicle, and the active center - of - gravity control unit includes a counterweight structure 2 and an adjustment motor 14 for driving the counterweight structure 2 to tilt; Step S2: Construct an affine non - linear dynamic model based on the two - wheel vehicle and the counterweight structure 2; Step S3: Establish an adaptive sliding - mode controller based on the affine non - linear dynamic model and the disturbance, and solve the affine non - linear dynamic model through the adaptive sliding - mode controller to output the input torque of the counterweight structure 2; Step S4: The adjustment motor 14 drives the counterweight structure 2 to tilt at a certain angle based on the input torque, so as to generate a restoring torque to make the two-wheeled vehicle return to the balanced state.

[0045] An adaptive center-of-gravity adjustment two-wheeled vehicle balance control method provided in this embodiment. The adaptive sliding mode controller is used to control the self-balancing of the two-wheeled vehicle on unstructured terrain. The proposed adaptive center-of-gravity adjustment two-wheeled vehicle balance control method can effectively suppress the influence of unstructured terrain disturbances and has good robustness. The two-wheeled vehicle designed in this embodiment has the advantages of high energy utilization rate, long endurance time, and strong robustness, has good passability under complex terrains such as rugged mountains, deserts, and gobi, and has broad application prospects in the fields of rescue, logistics distribution, inspection, and surveying.

[0046] The active center-of-gravity adjustment unit provided in this embodiment can realize the balance control of the two-wheeled vehicle robot during stationary and full-terrain operation. By adjusting the position of the active center-of-gravity control unit, the center-of-gravity position of the two-wheeled vehicle is changed, thereby generating the lateral restoring torque provided in this embodiment, and then adjusting the roll angle provided in this embodiment. When the two-wheeled vehicle tilts to any side, an adaptive center-of-gravity adjustment two-wheeled vehicle balance control method provided in this embodiment is used to control the active center-of-gravity adjustment unit of the two-wheeled vehicle, so that it quickly rotates to a specific angle in the opposite direction of the tilt, thereby obtaining a torque against gravity in the roll direction and making the two-wheeled vehicle adjust to the desired position.

[0047] In step S2 of this embodiment, an affine nonlinear dynamic model based on the two-wheeled vehicle and the counterweight structure 2 is constructed:

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056] Among them, respectively represent the masses of the two-wheeled vehicle and the counterweight structure 2, respectively represent the lengths of the two-wheeled vehicle and the counterweight structure 2, represents the distance from the two-wheeled vehicle to the underactuated joint, represents the distance from the center of gravity of the counterweight structure 2 to the drive joint, respectively represent the moments of inertia of the two-wheeled vehicle and the counterweight structure 2, is the acceleration due to gravity, is the roll angle of the two-wheeled vehicle, is the angle by which the counterweight structure 2 rotates relative to the two-wheeled vehicle, is the output torque of the adjustment motor 14, is the model uncertainty perturbation, is the external perturbation, represents the roll angle of the two-wheeled vehicle of the equivalent inertia term, represents the roll angle of the two-wheeled vehicle and the angle by which the counterweight structure 2 rotates relative to the two-wheeled vehicle between the inertial coupling terms, represents the angle by which the counterweight structure 2 rotates relative to the two-wheeled vehicle of the equivalent inertia term, is the roll angle of the two-wheeled vehicle of the gravitational torque, is the angle by which the counterweight structure 2 rotates relative to the two-wheeled vehicle of the gravitational torque, is the Coriolis force and centrifugal force terms of the vehicle body, is the Coriolis force and centrifugal force terms of the counterweight structure, is the roll angular velocity of the vehicle body, is the angular velocity of the counterweight structure, is the roll angular acceleration of the vehicle body, is the angular acceleration of the counterweight structure, 、 、 are respectively the function intermediate variables.

[0057] In step S3 of this embodiment, the perturbation includes model uncertainty and external perturbation , the external perturbation includes the perturbation of random lateral wind force, the error between the model and the real system, the friction generated by the rotation of the adjustment motor 14, and the vibration caused by rotation, etc. Assuming that the generated perturbation is within a certain range, then the perturbation satisfies:

[0058] where, is the model uncertainty threshold, is the external perturbation threshold.

[0059] In this embodiment, the non - linear coupling degree of the affine non - linear dynamic model is severe. Therefore, through diffeomorphic transformation, the original state system is mapped to another global coordinate system, becoming a cascade - form system that is easier to control, and an adaptive sliding - mode controller is designed for control. In step S4 of this embodiment, the method for establishing the adaptive sliding - mode controller is as follows: Step S401: Perform a global coordinate transformation. The original state system corresponding to the affine non - linear dynamic model is transformed into a new cascade - form system through diffeomorphic transformation, and the dynamic equation of the new cascade - form system is obtained; Step S402: Design a balancing controller for the dynamic equation of the new cascade - form system, set the sliding - mode surface, and establish an adaptive sliding - mode controller based on the balancing controller.

[0060] The method for performing a global coordinate transformation to transform the original state system corresponding to the affine non - linear dynamic model into a new system state through diffeomorphic transformation and establishing the dynamic equation of the new cascade - form system is as follows: In step S401 of this embodiment, obtaining the new cascade - form system is specifically as follows:

[0061]

[0062]

[0063]

[0064] Among them, is the original system state, is the state of the new cascade - form system, is the coupling state, is the generalized momentum, and are respectively the angle and velocity of the counterweight structure, is the core transformation function, is the Lagrangian function, which is used to describe the energy characteristics of the system and obtain the dynamic characteristics of the system through partial - derivative operations; The method for obtaining the dynamic equation of the new cascade - form system is specifically as follows:

[0065] Among them, represents the negative value of the gravitational torque of the generalized momentum , represents the comprehensive dynamic coupling term of the velocity of the counterweight structure, is the total disturbance of the coupling model uncertainty disturbance and the external disturbance;

[0066] Among them, is the equivalent mass coupling term.

[0067] In step S402 of this embodiment, the method for designing a balanced controller for the dynamic equation of the new cascaded form system, setting the sliding mode surface, and establishing an adaptive sliding mode controller based on the balanced controller is specifically as follows: The balanced controller is represented by the equilibrium point, specifically:

[0068] Then the equilibrium point of the new system state after the diffeomorphism mapping is:

[0069] The dynamic equation of the new system satisfies reversible, and bounded conditions; Design the sliding mode hyperplane:

[0070]

[0071] Among them, represents the deviation between the current roll state and the vertical position of the two-wheeled vehicle, represents the deviation of the dynamic characteristics of the current roll direction of the two-wheeled vehicle, represents the nonlinear characteristics of, represents the dynamic change rate of, are respectively the weight coefficients in the sliding mode hyperplane; According to the design method of the sliding mode controller for the underactuated system, design the sliding mode controller, and the input torque of the system is:

[0072]

[0073] Among them, is used for feedforward compensation based on the model, is used to cancel the error caused by model uncertainty and external disturbance, is a constant, represents the model uncertainty disturbance the maximum amplitude of, represents the external disturbance or the maximum amplitude of the coupling disturbance, is the sliding mode gain, is the sliding mode surface.

[0074] In summary, the underactuated two-wheeled vehicle configuration designed by the present invention has severe non-linear coupling and underactuated characteristics. Traditional linearization methods can only achieve approximate linearization within a very small range near the equilibrium point. Due to the non-linear coupling characteristics of the system of the present invention, global rigorous linearization cannot be performed. To address this difficulty, the present invention designs a global coordinate transformation to convert the affine non-linear dynamic model corresponding to the proposed configuration into a strict feedback cascade standard form, and designs a sliding mode controller to enable the drive part of the system to reach the sliding mode condition. Through the coupling relationship between the drive part and the underactuated part of the system, the self-stabilization of the underactuated part is finally achieved.

[0075] The counterweight structure 2 designed by the present invention. Utilizing the own weight of the two-wheeled vehicle without adding extra weight, it autonomously adjusts the center of gravity of the two-wheeled vehicle according to the change of the inclination angle of the two-wheeled vehicle, realizes the self-balancing of the two-wheeled vehicle under static and interference conditions, the maximum turning angle of the two-wheeled vehicle can reach ±12°, it has strong anti-interference ability, high energy utilization rate, and stable control effect.

[0076] The present invention designs an adaptive sliding mode controller to achieve optimal balance control; cooperates with the active center of gravity control unit and the two-wheeled vehicle to realize the self-balancing of the two-wheeled vehicle under driving and interference; has better performance under unstructured terrain and undulating terrain, has good robustness to state fluctuations caused by external random disturbances and terrain, and can smoothly pass through slopes with a height exceeding 4 times the wheel diameter of the two-wheeled vehicle; during the process of passing through continuous slopes such as blind paths and speed bumps, the roll angle of the two-wheeled vehicle never exceeds 5.7°.

[0077] According to the above technical solutions, a two-wheeled vehicle prototype is designed and its functions are experimentally verified and analyzed.

[0078] First, a return-to-normal experiment is carried out. The two-wheeled vehicle prototype with an added active center of gravity control unit, in cooperation with the adaptive sliding mode controller, can maintain balance on its own when stationary. The two-wheeled vehicle prototype is subjected to return-to-normal experiments at different angles, and the measured roll angles include 3°, 6°, 9°, and 12°. The experimental results are shown in Figures 3(a) and 3(b). The results show that the two-wheeled vehicle prototype can quickly return to normal within 1 s, reach the equilibrium point, the maximum return-to-normal angle can reach 12°, and the rotation angle of the counterweight structure 2 responds quickly within -85° to 57°.

[0079] Next, off-road experiments were conducted. To further verify the balance effect of the two-wheeled vehicle prototype, off-road experiments on the two-wheeled vehicle prototype were carried out under different terrains. The experimental terrains included speed bumps, pedestrian blind paths, and undulating slopes. The height of the speed bumps was 4 cm and 5 cm, and the height of the slope was 20 cm. The wheel diameter of the two-wheeled vehicle prototype was 4.62 cm. The experimental results are shown in Figures 4(a) and 4(b). For the continuously undulating pedestrian blind paths and speed bumps, the roll angle of the active center-of-gravity control unit changed continuously, and the change in the roll angle did not exceed 5.7°, which could ensure the balance of the two-wheeled vehicle prototype. For the slope with a height of 20 cm, the two-wheeled vehicle prototype could also pass quickly and smoothly.

[0080] Embodiment 2 Embodiment 2 provides an adaptive center-of-gravity adjustment two-wheeled vehicle balance control system, which is applied to the above-mentioned adaptive center-of-gravity adjustment two-wheeled vehicle balance control method, as Figure 5 shown, including: A two-wheeled vehicle balance module, which is used to set an active center-of-gravity control unit on the two-wheeled vehicle. The active center-of-gravity control unit includes a counterweight structure 2 and an adjustment motor 14 for driving the counterweight structure 2 to tilt; An affine nonlinear dynamics model module, which is used to construct an affine nonlinear dynamics model based on the two-wheeled vehicle and the counterweight structure 2; A disturbance acquisition module, which is used to acquire disturbances; An adaptive sliding mode controller module, which is used to set a sliding mode surface and establish an adaptive sliding mode controller based on the affine nonlinear dynamics model and the disturbance, and solve the affine nonlinear dynamics model through the adaptive sliding mode controller to output the input torque of the counterweight structure 2; An adjustment module, which is used to drive the counterweight structure to tilt a certain angle based on the input torque by the adjustment motor, so as to generate a restoring torque to make the two-wheeled vehicle return to the balanced state.

[0081] In this embodiment, the two-wheeled vehicle includes a first wheel 3, a second wheel 4, and a vehicle body 1. The first wheel 3 is arranged on the front side of the vehicle body 1, and the second wheel 4 is arranged on the rear side of the vehicle body 1. The first wheel 3 is steered by a first driving mechanism, and the second wheel 4 goes straight through a second driving mechanism. The counterweight structure 2 and the adjustment motor 14 are arranged on the vehicle body 1 and between the first wheel 3 and the second wheel 4, and are used to control the self-balancing of the two-wheeled vehicle under unstructured terrains.

[0082] The affine nonlinear dynamics model module is used to construct an affine nonlinear dynamics model based on the vehicle body 1 and the counterweight structure 2.

[0083] Specifically, the first driving mechanism includes a steering servo 7 and a front fork 11. The steering servo 7 is fixed on the vehicle body 1, the output shaft of the steering servo 7 is fixedly connected to the front fork 11, and the first wheel 3 is fixedly connected to the front fork 11 through a rotating shaft. The first wheel 3 is steered by driving the steering servo 7.

[0084] The second driving mechanism includes a brushless motor 8, a first transmission wheel 9, a second transmission wheel 10 and a synchronous belt 5. The brushless motor 8 is fixed on the vehicle body 1. The first transmission wheel 9 is fixedly connected to the output shaft of the brushless motor 8. The second transmission wheel 10 is fixedly connected to the second wheel 4. The synchronous belt 5 is sleeved on the first transmission wheel 9 and the second transmission wheel 10. The brushless motor 8 drives the first transmission wheel 9 to rotate, and then drives the second transmission wheel 10 and the second wheel 4 to rotate, so that the second wheel 4 generates forward and backward straight-line motions.

[0085] The vehicle body 1 adopts a hollow design in the middle for placing the brushless motor 8 that drives the second wheel 4 and the adjustment motor 14 that drives the counterweight structure 2. Each part is connected by bolts. Among them, the second wheel 4 and the vehicle body 1 are connected by a cross key to ensure the stability of the connection during the transmission process. In this embodiment, the seat and the chain structure are removed. The brushless motor 8 is connected to the second wheel 4 through the synchronous belt 5, the first transmission wheel 9 and the second transmission wheel 10, so as to realize the conversion of the rotation of the brushless motor 8 into the straight-line motion of the second wheel 4.

[0086] In this embodiment, the weight of the two-wheeler itself is utilized to change the center of gravity, improving the energy utilization rate and the endurance time.

[0087] In this implementation, the active center-of-gravity control unit further includes a main control board 6 and an attitude sensor 13. The main control board 6 is an STM32 control board, which is internally provided with an adaptive sliding mode controller. The attitude sensor 13 is an IMU sensor, which is used to receive the data of the attitude sensor 13. The required torque for balancing the two-wheeler is calculated by the adaptive center-of-gravity adjustment two-wheeler balance control method, and this torque is used as the control target of the center-of-gravity adjustment actuator to drive the counterweight structure 2 to move and change the center-of-gravity position of the two-wheeler. When the two-wheeler tilts, the counterweight structure 2 moves in the opposite direction to generate a restoring torque, so that the two-wheeler returns to the balanced position. The counterweight structure 2 is internally provided with a battery 12 and / or other goods to be transported, which is not only used to balance the two-wheeler, but also can supply power. The weight of the devices of the two-wheeler itself is fully utilized to change the center of gravity, with high energy utilization rate and long endurance time. By adjusting the relative position of the counterweight structure 2 and the two-wheeler, the center-of-gravity position of the two-wheeler is changed, generating a lateral restoring torque of the two-wheeler, and then the roll angle of the two-wheeler is adjusted. When the two-wheeler tilts to any side, the active center-of-gravity control unit is controlled by the adaptive center-of-gravity adjustment two-wheeler balance control method proposed by the present invention, so that it quickly rotates to a specific angle in the opposite direction of the tilt, thereby obtaining a torque against gravity in the roll direction, and adjusting the two-wheeler to the desired position. The weight of the two-wheeler is fully utilized to change the center of gravity, with high energy utilization rate, long endurance time, strong robustness and stable driving.

[0088] In this embodiment, the adaptive sliding mode controller takes the attitude of the two-wheeled vehicle and the position of the counterweight structure 2 of the active center of gravity control unit as inputs, outputs a center of gravity adjustment command, controls the adjustment work, and realizes the balance control of the two-wheeled vehicle. Based on the vehicle dynamics model, an adaptive sliding mode controller is designed, which makes up for the influence of model uncertainty and external disturbances and has strong robustness.

[0089] In this embodiment, it also includes a host computer and a receiving module. The receiving module is arranged on the two-wheeled vehicle to receive the instructions of the host computer, so that the first wheel 3 turns and / or the second wheel 4 goes straight through the second driving mechanism. The receiving module is a Bluetooth receiver or a WIFI receiver.

[0090] In this embodiment, the specific method for adjusting the vehicle body 1 is as follows: Obtain the attitude information of the two-wheeled vehicle through the attitude sensor 13, start the adaptive center of gravity adjustment two-wheeled vehicle balance control method, and calculate the torque required to balance the two-wheeled vehicle; According to the torque, drive the counterweight structure 2 to move by adjusting the motor 14, change the position of the center of gravity of the two-wheeled vehicle, and balance the two-wheeled vehicle; Receive the forward and steering instructions transmitted from the host computer through the receiving module, and the main control board 6 executes the commands; Control the second driving mechanism to drive the first wheel 3 to rotate and control the second driving mechanism to drive the second wheel 4 to go straight through the main control board 6, and control the operation of the two-wheeled vehicle.

[0091] As Figure 7 , it is a schematic diagram of the balanced state of the two-wheeled vehicle of the present invention; as Figure 8 shown, it is a schematic diagram of the two-wheeled vehicle restoring balance in the first direction tilt state. When the two-wheeled vehicle tilts to the left by a certain angle, the counterweight structure 2 tilts to the right by a certain angle to balance the two-wheeled vehicle; as Figure 9 shown, it is a schematic diagram of the two-wheeled vehicle restoring balance in the second direction tilt state. When the two-wheeled vehicle tilts to the right by a certain angle, the counterweight structure 2 tilts to the left by a certain angle to balance the two-wheeled vehicle.

[0092] In this embodiment, the STM32 main control board 6 is selected as the main control module, and an IMU sensor is carried to identify the attitude of the two-wheeled vehicle. The IMU sensor communicates with the main control board 6 through the USART serial port; the main control board 6 is equipped with an RS485 serial port to send control signals to the adjustment motor 14 of the active center of gravity control unit; the main control board 6 drives the brushless motor 8 through the PWM interface to provide control signals; the main control board 6 communicates with the servo control board of the steering servo 7 through the USART serial port; the main control board 6 is connected to the receiving module through the USART serial port to realize communication with the host computer.

[0093] In the specific implementation of this embodiment, the IMU sensor selects the six-axis inertial measurement unit BMI088, which measures the three-axis acceleration and three-axis angular velocity through the accelerometer and gyroscope, and calculates the attitude angle of the body 1 of the two-wheeler through algorithms such as Kalman filtering. The attitude calculation frequency is not less than 200Hz, and the attitude accuracy is better than 0.5°, which can meet the requirements of self-balancing control. The IMU sensor is connected to the main control board 6 through the RS485 interface, and the transmission rate is not less than 115200bps to ensure the real-time and reliable data transmission.

[0094] In the specific implementation of this embodiment, the main control board 6 selects the high-performance microcontroller STM32H743, with a main frequency of not less than 168MHz and a Flash storage capacity of not less than 512KB. It has rich peripheral interfaces such as UART, CAN, SPI, IIC, etc., which can meet the operation requirements of multi-sensor data fusion and complex control algorithms. The power supply voltage of the main control board 6 is 12V, and a DC-DC module is used to step down to 3.3V and 5V to supply power to each module, and power reverse connection protection and TVS suppression protection circuits are provided to improve the reliability of the control system.

[0095] In the specific implementation of this embodiment, the adjustment motor 14 in the active center of gravity control unit uses the XM540-W270-T / R motor of ROBOTIS, which is built-in with an absolute encoder and provides a maximum torque of 10.6N·m under 12V power supply; it can achieve high-precision position and speed control.

[0096] In the specific implementation of this embodiment, the steering control module of the steering servo 7 uses the 50KG double-axis servo RP8-U50H-M of Fashion Star, which is equipped with an absolute encoder and the effective rotation angle is 0-360°.

[0097] In the specific implementation of this embodiment, the brushless motor 8 selects the X2216-KV880 of Langyu, which supports CAN bus and PWM signal control, and can achieve efficient, stable and low-noise drive control. The synchronous belt 5 is 20mm wide and 400mm long, made of high-strength polyurethane material, with the characteristics of anti-tensile, wear-resistant and corrosion-resistant, and has a long service life. The synchronous belt 5 is connected to the first driving wheel 9 and the second driving wheel 10, with sufficient driving torque to ensure the power output of the wheels.

[0098] In the specific implementation of this embodiment, the batteries 12 are combined in series and parallel to form a battery 12 group, which provides power for the entire system. The battery 12 group is installed in a waterproof and dustproof configuration bin and is equipped with an intelligent power management system, which can monitor parameters such as the voltage, current, and temperature of the batteries 12 in real time and has functions such as overcharge and over-discharge protection, short-circuit protection, and balanced charging, ensuring the reliability and safety of the power supply system. It is connected to the main control board 6 through a plug, facilitating replacement and maintenance.

[0099] In the specific implementation of this embodiment, the receiving module selects a Bluetooth receiver, and the Bluetooth serial port transparent transmission module selected by the Bluetooth receiver is of the HC06 model to receive the signal transmitted from the upper computer.

[0100] In summary, during the use of an adaptive center-of-gravity adjustment two-wheeled vehicle balance control system provided by this embodiment, it specifically includes: After the main control board 6 is powered on, it establishes communication with the IMU sensor through the RS485 serial port to obtain attitude information such as the pitch angle, roll angle, and heading angle of the vehicle body 1 of the two-wheeled vehicle in real time, and establishes communication with the upper computer through the on-board UART serial port to receive the control instructions and parameter settings sent by the upper computer; After the main control board 6 receives the attitude data sent by the IMU sensor, it starts the adaptive center-of-gravity adjustment two-wheeled vehicle balance control method. According to the attitude angle of the two-wheeled vehicle, it calculates in real time the balance torque required by the two-wheeled vehicle. This torque is used as the control target of the active center-of-gravity control unit and is sent to the adjustment motor 14 through the RS485 serial port. The adaptive center-of-gravity adjustment two-wheeled vehicle balance control method is based on the two-wheeled vehicle dynamics model and designs an adaptive sliding mode control law, which can adjust the control parameters in real time according to different working conditions and has strong robustness, capable of effectively suppressing the influence of model uncertainty and external disturbances; After the adjustment motor 14 receives the torque instruction sent by the main control board 6, it precisely controls the rotation angle and speed of the motor shaft through a servo control algorithm, driving the counterweight structure 2 to slide longitudinally along the two-wheeled vehicle, changing the center-of-gravity position of the two-wheeled vehicle. The mass block uses the battery 12 as the counterweight structure 2, which has a large mass and can significantly change the center-of-gravity position. When the two-wheeled vehicle tilts to the left (right) side, the counterweight structure 2 will move to the right (left) side, generating a restoring torque to push the two-wheeled vehicle back to the right (left), and finally keeping the two-wheeled vehicle in a balanced position; The main control board 6 controls the drive electronic speed controller of the brushless motor 8 through the PWM interface, thereby controlling the rotation speed of the brushless motor 8. The brushless motor 8 transmits power to the second wheel 4 through the synchronous belt 5 to drive the two-wheeler to go straight. The rotation speed of the brushless motor 8 is adjusted in real time according to the difference between the target speed and the actual speed of the two-wheeler through the PID control algorithm to ensure the stable and accurate driving of the two-wheeler. The speed feedback signal is provided by the Hall encoder on the second wheel 4. The encoder measures the speed through the Hall effect and sends the speed pulse signal to the main control board 6 for speed closed-loop control; The main control board 6 communicates with the servo control board of the steering servo 7 through the UART serial port. When receiving the steering control instruction sent by the upper computer, the main control board 6 calculates the target angle of the first wheel 3 according to the error between the current position of the two-wheeler and the desired trajectory, and sends this angle to the servo control board through the UART serial port. The servo control board controls the rotation of the steering servo 7 according to the received target angle, driving the front fork 11 and the first wheel 3 to turn, so that the two-wheeler travels along the desired trajectory.

[0101] Embodiment 3 Embodiment 3 provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the above-mentioned two-wheeler balance control method for adaptive center-of-gravity adjustment.

[0102] The processor selects the STM32 main control board 6, which is equipped with an IMU sensor for attitude recognition of the two-wheeler. The IMU sensor communicates with the STM32 main control board 6 through the USART serial port. The STM32 main control board 6 sends control signals to the adjustment motor 14 of the active center-of-gravity control unit and the two-wheeler.

[0103] Embodiment 4 Embodiment 4 provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the above-mentioned two-wheeler balance control method for adaptive center-of-gravity adjustment.

[0104] The above embodiments are only illustrative examples of the technical solutions of the present invention. The methods involved in the present invention are not limited to the content described in the above embodiments, but are subject to the scope defined by the claims. Any modification, supplement, or equivalent replacement made by those skilled in the art of the present invention on the basis of this embodiment is within the scope protected by the claims of the present invention.

Claims

1. An adaptive center-of-gravity adjustment two-wheeler balance control method, characterized in that, Including: An active center-of-gravity control unit is provided on the two-wheeler. The active center-of-gravity control unit includes a counterweight structure and an adjustment motor for driving the counterweight structure to tilt. Construct an affine nonlinear dynamic model based on the two-wheeler and the counterweight structure. Based on the affine nonlinear dynamic model and the disturbance, establish an adaptive sliding mode controller, and solve the affine nonlinear dynamic model through the adaptive sliding mode controller to output the input torque of the counterweight structure. The adjustment motor drives the counterweight structure to tilt at a certain angle based on the input torque to generate a restoring torque to make the two-wheeler return to the balanced state.

2. The adaptive center-of-gravity adjustment two-wheeled vehicle balance control method according to claim 1, wherein, The affine nonlinear dynamic model is: Wherein, respectively represent the masses of the two-wheeled vehicle and the counterweight structure, respectively represent the lengths of the two-wheeled vehicle and the counterweight structure, represents the distance from the two-wheeled vehicle to the underactuated joint, represents the distance from the center of gravity of the counterweight structure to the driving joint, respectively represent the moments of inertia of the two-wheeled vehicle and the counterweight structure, is the acceleration due to gravity, is the roll angle of the two-wheeled vehicle, is the angle of rotation of the counterweight structure relative to the two-wheeled vehicle, is the output torque of the adjustment motor, is the model uncertainty perturbation, is the external perturbation, represents the roll angle of the two-wheeled vehicle of the equivalent inertia term, represents the roll angle of the two-wheeled vehicle and the angle of rotation of the counterweight structure relative to the two-wheeled vehicle between the inertia coupling terms, represents the angle of rotation of the counterweight structure relative to the two-wheeled vehicle of the equivalent inertia term, is the roll angle of the two-wheeled vehicle of the gravity moment, is the angle of rotation of the counterweight structure relative to the two-wheeled vehicle of the gravity moment, is the Coriolis force and centrifugal force terms of the vehicle body, is the Coriolis force and centrifugal force terms of the counterweight structure, is the roll angular velocity of the vehicle body, is the angular velocity of the counterweight structure, is the roll angular acceleration of the vehicle body, is the angular acceleration of the counterweight structure, , , are respectively the function intermediate variables.

3. The adaptive center-of-gravity adjustment two-wheeler balance control method according to claim 2, wherein The method for establishing the adaptive sliding mode controller is: Perform a global coordinate transformation to transform the original state system corresponding to the affine nonlinear dynamic model into a new cascaded form system through a diffeomorphism transformation, and obtain the dynamic equation of the new cascaded form system. Design a balance controller for the dynamic equation of the new cascaded form system, set the sliding surface, and establish an adaptive sliding mode controller based on the balance controller.

4. The adaptive center-of-gravity adjustment two-wheeler balance control method according to claim 3, characterized in that The method for performing a global coordinate transformation to transform the original state system corresponding to the affine nonlinear dynamic model into a new system state through a diffeomorphism transformation and establishing the dynamic equation of the new cascaded form system is: Obtain the new system state, specifically: Among them, is the original system state, is the new cascaded form system state, is the coupling state, is the generalized momentum, and are respectively the angle and velocity of the counterweight structure, is the core transformation function, is the Lagrangian function, which is used to describe the energy characteristics of the system and obtain the dynamic characteristics of the system through partial derivative operations; Obtain the dynamic equation of the new cascaded form system, specifically: Among them, represents the negative value of the gravitational moment of the generalized momentum, represents the comprehensive dynamic coupling term of the velocity of the counterweight structure, is the total disturbance that couples the model uncertainty disturbance and the external disturbance; Among them, is the equivalent mass coupling term.

5. The adaptive center-of-gravity adjustment two-wheeled vehicle balance control method according to claim 4, wherein The method for designing a balance controller for the dynamic equation of the new cascaded form system, setting the sliding surface, and establishing an adaptive sliding mode controller based on the balance controller is specifically: The balance controller is represented by the equilibrium point, specifically Then the equilibrium point of the new system state after the diffeomorphism mapping is: The new system dynamics equation satisfies reversibility and the condition of boundedness; Design the sliding mode hyperplane: Among them, represents the deviation of the current roll state of the two-wheeled vehicle from the vertical position, represents the deviation of the dynamic characteristics of the current roll direction of the two-wheeled vehicle, represents the nonlinear characteristics, represents the dynamic change rate of, are respectively the weight coefficients in the sliding mode hyperplane; According to the design method of the sliding mode controller for the underactuated system, design the sliding mode controller, and the input torque of the system is: Among them, is used for feedforward compensation based on the model, to offset the errors caused by model uncertainty and external disturbances, is a constant, represents the maximum amplitude of the model uncertainty disturbance ; represents the maximum amplitude of the external disturbance or the coupling disturbance, is the sliding mode gain, is the sliding mode surface. It should be noted that there seems to be a semicolon (;) missing in the original Chinese text at the end of the description of the maximum amplitude of the model uncertainty disturbance in the English translation. It is recommended to check and correct the original text if necessary.

6. An adaptive center-of-gravity adjustment two-wheeler balance control system, characterized in that, Including: A two-wheeler balance module for providing an active center-of-gravity control unit on the two-wheeler. The active center-of-gravity control unit includes a counterweight structure and an adjustment motor for driving the counterweight structure to tilt. An affine nonlinear dynamic model module for constructing an affine nonlinear dynamic model based on the two-wheeler and the counterweight structure. An adaptive sliding mode controller module for establishing an adaptive sliding mode controller based on the affine nonlinear dynamic model and the disturbance, and solving the affine nonlinear dynamic model through the adaptive sliding mode controller to output the input torque of the counterweight structure. An adjustment module for driving the counterweight structure to tilt at a certain angle based on the input torque through the adjustment motor to generate a restoring torque to make the two-wheeler return to the balanced state.

7. The adaptive center-of-gravity adjustment two-wheeler balance control system according to claim 6, wherein: In the two-wheeler balance module, the two-wheeler includes a first wheel, a second wheel, and a vehicle body. The first wheel is provided on the front side of the vehicle body, the second wheel is provided on the rear side of the vehicle body. The first wheel is steered by a first drive mechanism, the second wheel goes straight through a second drive mechanism, and the counterweight structure and the adjustment motor are provided on the vehicle body and between the first wheel and the second wheel. The affine nonlinear dynamic model module is used to construct an affine nonlinear dynamic model based on the vehicle body and the counterweight structure.

8. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the adaptive center-of-gravity adjustment two-wheeler balance control method according to any one of claims 1 to 5.

9. The electronic device according to claim 8, characterized in that: The processor selects an STM32 main control board, which is equipped with an IMU sensor for two-wheeler attitude recognition. The IMU sensor communicates with the STM32 main control board through the USART serial port, and the STM32 main control board sends control signals to the adjustment motor of the active center-of-gravity control unit and the two-wheeler.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the adaptive center-of-gravity adjustment two-wheeler balance control method according to any one of claims 1 to 5.

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