A wall step transition motion process control method of a multi-mode mobile robot

Abstract

The application discloses a kind of wall surface step transition movement process control methods of multi-mode mobile robot, comprising: based on the dynamics equation of the step transition process of multi-mode mobile robot is constructed to the constraint of changing environment;Analysis transition process, the attitude angle trajectory planning of multi-mode mobile robot transition process is carried out, and the attitude angle trajectory planning result is input into controller as control target quantity, realizes the trajectory tracking control of attitude angle;Based on adaptive sliding mode control, the attitude angle controller of the step transition process of multi-mode mobile robot is designed, and according to position open-loop control quantity and attitude closed-loop control quantity, a mixed controller is designed;The virtual control quantity output by the mixed controller is converted into drive element control instruction, input into drive element, corresponding movement is generated, so as to change the position and attitude of multi-mode mobile robot, complete step transition.The application can realize the step transition process of multi-mode mobile robot.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mobile robots, in particular to a wall step transition motion process control method of a multi-mode mobile robot. BACKGROUND

[0002] In the field of robots, mobile robots have always been a research hotspot and have been maturely applied in industrial production, logistics transportation and military reconnaissance fields to undertake corresponding work tasks. With the deepening of research, in order to cope with the needs of complex working environment and diversified tasks, mobile robots need to break through the limitations of single motion mode and have the ability of multi-mode motion, therefore, multi-mode mobile robot system emerges as the times require. Since the multi-mode mobile robot greatly expands the working space of the mobile robot, it can adapt to more complex working environment and has more flexible working ability, so it has broad application prospect and great development potential.

[0003] Multi-mode mobile robot refers to a mobile robot with multiple motion modes. By integrating multiple motion mechanisms and cooperating with control strategies for different scenes, flexible movement in different terrains can be achieved by switching motion modes, such as wheel-leg multi-mode mobile robot, wheel-track multi-mode mobile robot, flight-ground multi-mode mobile robot, ground-underwater multi-mode mobile robot, and ground-wall climbing multi-mode mobile robot. The control method proposed in the present application is mainly for a multi-mode robot that can realize ground and wall motion.

[0004] The domestic control method research based on wall climbing robots includes the following published patents: a wall climbing robot control method, device, equipment and storage medium, a wall climbing robot control method, etc. Similar foreign research includes the VertiGo robot of the Swiss Federal Institute of Technology.

[0005] The current research and technology focus on solving the stable wall climbing control of the robot on relatively flat walls. However, during the process of climbing a vertical wall, the actual wall climbing robot still has a motion similar to climbing a step, such as the scenario of the robot climbing from a vertical wall to a horizontal platform. At this time, the robot needs to turn 90° from the vertical wall climbing state to the horizontal motion state, and the existing multi-mode wall climbing robot has not solved this problem. The motion transition process from the vertical wall to the horizontal platform requires a significant change in the position and attitude of the multi-mode mobile robot to achieve it, which puts higher requirements on the stable control of the robot and needs to propose a targeted motion control strategy. SUMMARY

[0006] To address the technical problems existing in the prior art, this invention proposes a control method for the transition motion of a multi-mode mobile robot over a wall or step. This control method is based on a hybrid control method that combines open-loop control and closed-loop attitude control, enabling the multi-mode mobile robot to achieve the transition motion from a vertical wall to a horizontal step.

[0007] To achieve the above objectives, the present invention provides a method for controlling the transition motion of a multi-mode mobile robot on a wall staircase, comprising:

[0008] Based on changing environmental constraints, a dynamic model of the step transition process of a multi-mode mobile robot is constructed.

[0009] The step transition process of the multi-mode mobile robot is analyzed, the attitude angle trajectory of the multi-mode mobile robot transition process is planned, and the attitude angle trajectory planning result is used as the control target quantity of the multi-mode mobile robot and input into the controller to realize the trajectory tracking control of the attitude angle.

[0010] An attitude angle controller for a multi-mode mobile robot with a step transition process based on adaptive sliding mode control is designed, and a hybrid controller is designed based on the open-loop control quantity of position and the closed-loop control quantity of attitude.

[0011] The virtual control quantity output by the mixer is converted into control commands for the drive element, which are then input into the drive element to generate corresponding motion, thereby changing the position and posture of the multi-mode mobile robot and completing the step transition process.

[0012] Preferably, the dynamic model of the step transition process of the multi-mode mobile robot is as follows:

[0013]

[0014] In the formula, These are the accelerations in the Y and Z directions at the center of mass of the multi-mode mobile robot, respectively. These are the roll angle and angular acceleration at the center of mass of the multi-mode mobile robot, respectively; F af F ar These represent the aerodynamic forces generated by the front and rear propellers of the multi-mode mobile robot; α f α r These represent the angles of the front and rear vector servos of the multi-mode mobile robot; I x Let l be the rotational inertia about the X-axis at the center of mass of the multimodal mobile robot; af l ar N represents the vertical distance from the center of the two propellers of the multi-mode mobile robot to its center of mass; Z M N These are the unknown environmental constraints and the constraint torques they generate.

[0015] Preferably, the posture angle trajectory planning of the multi-mode mobile robot transition process comprises:

[0016] According to the initial state roll angle and the terminal state roll angle of the step transition process, B-spline interpolation processing is performed to obtain a posture angle trajectory planning result.

[0017] Preferably, in the step transition process, the initial state of the multi-mode mobile robot is that the front wheels are suspended on the water platform surface and the rear wheels contact the vertical wall surface, and the terminal state of the multi-mode mobile robot is that both wheels are located on the water platform surface.

[0018] Preferably, the posture angle controller of the multi-mode mobile robot step transition process is designed based on adaptive sliding mode control, comprising:

[0019] A sliding surface is defined.

[0020] Based on the sliding surface, an adaptive sliding mode control law and an environmental constraint torque adaptive estimation law are designed respectively.

[0021] According to the adaptive sliding mode control law and the environmental constraint torque adaptive estimation law, a Lyapunov function V is constructed, and if the Lyapunov function V satisfies V≥0 and then the control is stable; wherein, is the derivative of Lyapunov.

[0022] Preferably, the sliding surface is:

[0023]

[0024] In the formula, c is a sliding surface design parameter; and s are the error values of the roll angle and the angular velocity of the multi-mode mobile robot respectively, and s is a sliding surface.

[0025] The adaptive sliding mode control law is:

[0026]

[0027] In the formula, M is the closed-loop control output of the posture controller; is the expected angular acceleration of the roll angle at the center of mass of the multi-mode mobile robot; and ε is an equal-speed approach law parameter. is the estimated value of the environmental constraint torque; I x is the moment of inertia of the multi-mode mobile robot around the X axis at the center of mass; and sgn(s) is a function of the sliding surface s, sgn(s)=1 when s>0, and sgn(s)=-1 when s<0.

[0028] The environmental constraint torque adaptive estimation law is:

[0029]

[0030] wherein, is an environment constraint torque adaptive estimation law;

[0031] The Lyapunov function V is:

[0032]

[0033] wherein, is the error between the actual value of the environmental torque and the estimated value of the environmental torque.

[0034] Preferably, the mixing controller is designed according to the position open-loop control quantity and the attitude closed-loop control quantity, comprising:

[0035] The attitude control quantity generated by the attitude closed-loop controller is combined with the open-loop control quantity converted from the open-loop remote control instruction, and the mixed control quantity is distributed through the mixing controller. The distributed instruction is converted into a control instruction and transmitted into the driving element, so as to finally control the multi-mode mobile robot to generate motion;

[0036] The mixing controller equation is:

[0037]

[0038] wherein, F yf , F yr , F zf , F zr are the y-axis and z-axis components of the aerodynamic force generated by the front and rear groups of propellers of the multi-mode mobile robot; F y , F z are open-loop control quantities input by a remote controller; M is a closed-loop control quantity output by an attitude controller; l af , l ar are vertical distances from the centers of the two groups of propellers to the center of mass of the multi-mode mobile robot.

[0039] Preferably, the virtual control quantity output by the mixing controller is converted into a driving element control quantity as follows:

[0040]

[0041] wherein, F af is an aerodynamic force control quantity of the front group of propellers; F ar is an aerodynamic force control quantity of the rear group of propellers; α f is a vector rudder angle control quantity of the front group of propellers; α r is an angle control quantity of the rear group of vector rudders.

[0042] Preferably, the position and attitude of the multi-mode mobile robot are changed, comprising:

[0043] After obtaining the control amount of the aerodynamic force of each propeller and the control amount of the angle of the vector rudder, the control instructions are converted and input into the driving element, and the driving element is controlled to generate corresponding actions, thereby changing the position and posture of the multi-mode mobile robot.

[0044] Preferably, under the condition of relying only on the attitude angle feedback, the multi-mode mobile robot realizes the step transition process through the mixed architecture of open-loop position control and closed-loop attitude control.

[0045] Compared with the prior art, the present application has the following advantages and technical effects:

[0046] (1) The present application proposes a wall step transition motion process control method for a multi-mode mobile robot. Through this control method, the step transition process of the multi-mode mobile robot can be realized. That is, by controlling the speed of the propeller carried by the multi-mode mobile robot and the angle of the vector rudder, the size and direction of the aerodynamic force generated thereby are controlled, thereby controlling the movement of the position and the change of the posture of the multi-mode mobile robot, and completing the step transition process of the multi-mode mobile robot from the vertical wall to the water platform;

[0047] (2) Based on the mixed control mode combining open-loop control and closed-loop control, the propeller and the vector rudder carried by the multi-mode mobile robot are dynamically adjusted by the mixed controller, so that the step transition process of the multi-mode mobile robot is completed without exceeding the physical limit, and the problem of controlling the step transition process of the multi-mode mobile robot without relying on global state feedback is solved in the case that the sensor resources carried by the multi-mode mobile robot system are limited. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this application. The embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0049] Figure 1 A flow chart of a wall step transition motion process control method for a multi-mode mobile robot according to an embodiment of the present application;

[0050] Figure 2 A control process schematic diagram of a multi-mode mobile robot step transition process according to an embodiment of the present application;

[0051] Figure 3 An application flow chart of a wall step transition motion process control method for a multi-mode mobile robot according to an embodiment of the present application;

[0052] Figure 4 A multi-mode mobile robot step transition process coordinate system established in a mechanical analysis diagram according to an embodiment of the present application;

[0053] Figure 5 A schematic diagram of a desired motion process for a step transition of a multi-mode mobile robot according to an embodiment of the application;

[0054] Figure 6 A schematic diagram of a planned attitude angle trajectory for a step transition process of a multi-mode mobile robot according to an embodiment of the application;

[0055] Figure 7 A schematic diagram of a simulation result of attitude angle trajectory tracking for a step transition process of a multi-mode mobile robot according to an embodiment of the application;

[0056] Figure 8 A schematic diagram of a simulation result of attitude centroid trajectory for a step transition process of a multi-mode mobile robot according to an embodiment of the application. DETAILED DESCRIPTION

[0057] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0058] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a group of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown herein.

[0059] The embodiment proposes a wall step transition motion process control method for a multi-mode mobile robot, as shown in Figure 1 , comprising:

[0060] Based on the changing environmental constraints, a dynamics model of the step transition process of the multi-mode mobile robot is constructed;

[0061] The step transition process of the multi-mode mobile robot is analyzed, the attitude angle trajectory of the multi-mode mobile robot transition process is planned, and the attitude angle trajectory planning result is input as a control target quantity of the multi-mode mobile robot into the controller to realize the trajectory tracking control of the attitude angle;

[0062] An attitude angle controller for the step transition process of the multi-mode mobile robot is designed based on adaptive sliding mode control, and a hybrid controller is designed according to the position open-loop control quantity and the attitude closed-loop control quantity;

[0063] The virtual control quantity output by the hybrid controller is converted into a driving element control instruction, which is input into the driving element to generate corresponding motion, thereby changing the position and attitude of the multi-mode mobile robot and completing the step transition process.

[0064] Specifically, the embodiment is directed to a wheeled multi-mode mobile robot based on the propelling of rotor aerodynamic force, and proposes a transition motion control method enabling the robot to smoothly transition from a vertical wall surface to a water platform. The robot is equipped with a passive wheeled mobile mechanism, and can freely move on the ground and on the wall through a four-rotor propulsion system with the ability to adjust the direction of the aerodynamic force vector. In the ground moving mode, the multi-mode mobile robot can change the direction of the aerodynamic force vector generated by the propeller by controlling the angle of the vector rudder, thereby providing the driving force required for the movement of the multi-mode mobile robot, and realizing the motion of the multi-mode mobile robot on the flat ground. In the wall climbing mode, the multi-mode mobile robot changes the direction of the aerodynamic force vector generated by the propeller, so that the aerodynamic force can simultaneously provide the compression force required for the multi-mode mobile robot to climb the wall and the driving force for the movement on the wall, thereby realizing the motion of the multi-mode mobile robot climbing the wall.

[0065] The multi-mode mobile robot is equipped with four propellers and two vector rudders as driving elements. The aerodynamic force generated by each propeller can be independently controlled. The two propellers are grouped in the direction of the vehicle head, and each two propellers are connected to one vector rudder. The vector direction of the aerodynamic force generated by the two groups of propellers can be independently adjusted by controlling the angles of the front and rear vector rudders. By controlling the size and vector direction of the aerodynamic force generated by the propeller, the roll angle attitude and the position along the Y and Z axes of the multi-mode mobile robot are changed, so that the multi-mode mobile robot realizes the action of crossing the wall convex angle and moves from the vertical wall to the water platform.

[0066] In view of the task requirement of the robot to perform step transition motion during wall climbing movement, the embodiment provides a transition motion process control method for the multi-mode mobile robot to cross the steps on the wall surface, which can enable the multi-mode mobile robot to smoothly transition from the vertical wall to the water platform and complete the step crossing action on the wall surface.

[0067] Further, the effect of the size of the aerodynamic force generated by the propeller and the rotation angle of the vector rudder on the center of mass of the multi-mode mobile robot is analyzed. During the step transition process, the center of mass of the multi-mode mobile robot moves horizontally and vertically, and rotates along the direction perpendicular to the horizontal direction. The horizontal direction is defined as the Y axis, the vertical direction is defined as the Z axis, and the direction perpendicular to the horizontal direction is defined as the X axis. The angle of rotation around the X axis direction is the roll angle The establishment of the coordinate system and the mechanical analysis of the step transition process of the multi-mode mobile robot are shown in Figure 4 .

[0068] The multi-mode mobile robot dynamics model based on the Newton-Euler method is as follows:

[0069]

[0070] In the formula, are the Y and Z direction accelerations at the center of mass of the multi-mode mobile robot, respectively; are the roll angle and angular acceleration at the center of mass of the multi-mode mobile robot, respectively;F af , F ar are the aerodynamic forces generated by the front and rear propellers of the multi-mode mobile robot; a f , a r are the angles of the front and rear rudders of the multi-mode mobile robot; I x is the moment of inertia of the multi-mode mobile robot around the X axis at the center of mass; l af , l ar are the vertical distances from the centers of the two groups of propellers to the center of mass of the multi-mode mobile robot; N Z , M N are the unknown environmental constraint forces and the constraint torques generated thereby.

[0071] Further, the attitude angle trajectory planning for the transition process of the multi-mode mobile robot is performed, including:

[0072] According to the starting state roll angle and the ending state roll angle of the step transition process, B-spline interpolation processing is performed to obtain the attitude angle trajectory planning result.

[0073] Specifically, the starting position of the step transition process of the multi-mode mobile robot is that the front wheel is suspended on the water platform surface and the body is inclined and parked on the wall convex corner, and the ending position is that both wheels of the multi-mode mobile robot are located on the water platform surface. The starting position and the ending position of the entire step transition process are fixed, and the initial position attitude angle of the multi-mode mobile robot is measured by experiment or simulation, and the ending position attitude angle is 0 degrees. The initial position and the ending position are used to plan the trajectory of the attitude angle of the multi-mode mobile robot.

[0074] In the step transition process, the starting state is that the front wheel of the multi-mode mobile robot is suspended on the water platform surface and the rear wheel contacts the vertical wall surface, and the ending state is that both wheels of the multi-mode mobile robot are located on the water platform surface.

[0075] Further, the result of the attitude angle trajectory planning is preset in the controller of the multi-mode mobile robot as the control target quantity input into the controller, so that the trajectory tracking control of the attitude angle can be realized through the controller.

[0076] Further, the attitude angle controller for the step transition process of the multi-mode mobile robot is designed based on adaptive sliding mode control, including:

[0077] a sliding surface is defined;

[0078] based on the sliding surface, an adaptive sliding mode control law and an environmental constraint torque adaptive estimation law are designed, respectively;

[0079] According to the adaptive sliding mode control law and the environment constraint torque adaptive estimation law, a Lyapunov function V is constructed, if the Lyapunov function V satisfies V ≥ 0 and then the control is stable; wherein, is the derivative of the Lyapunov function.

[0080] Specifically, the sliding mode surface is:

[0081]

[0082] In the formula, c is a sliding mode surface design parameter; respectively, the error value and the angular velocity error value of the roll angle of the multi-mode mobile robot, s is a sliding mode surface;

[0083] The adaptive sliding mode control law is:

[0084]

[0085] In the formula, M is the closed-loop control output of the attitude controller; is the expected angular acceleration of the roll angle at the center of mass of the multi-mode mobile robot; and ε is a constant approach law parameter; is the estimated value of the environment constraint torque; I x is the rotational inertia of the multi-mode mobile robot around the X axis at the center of mass; sgn(s) is a function of the sliding mode surface s, sgn(s) = 1 when s > 0, and sgn(s) = -1 when s < 0;

[0086] The environment constraint torque adaptive estimation law is:

[0087]

[0088] In the formula, is the environment constraint torque adaptive estimation law;

[0089] The Lyapunov function V is:

[0090]

[0091] In the formula, is the error between the actual value of the environmental torque and the estimated value of the environmental torque, and the calculation method is

[0092] Further, a hybrid controller is designed according to the position open-loop control and the attitude closed-loop control, comprising:

[0093] The attitude control quantity generated by the attitude closed-loop controller is combined with the open-loop control quantity converted from the open-loop remote control instruction, power distribution is performed through the hybrid controller, the distributed instruction is converted into a control instruction and transmitted into the driving element, and finally the motion of the multi-mode mobile robot is controlled;

[0094] The hybrid controller equation is:

[0095]

[0096] In the formula, F yf , F yr , F zf , and F zr are the y-axis and z-axis components of the aerodynamic forces generated by the front and rear groups of propellers of the multi-mode mobile robot; F y , F z are open-loop control quantities input by the remote controller; M is a closed-loop control quantity output by the attitude controller; l af , l ar are the vertical distances from the centers of the two groups of propellers to the center of mass of the multi-mode mobile robot.

[0097] Further, converting the virtual control quantity output by the hybrid controller into a driving element control quantity specifically comprises:

[0098]

[0099] In the formula, F af is the aerodynamic force control quantity of the front group of propellers; F ar is the aerodynamic force control quantity of the rear group of propellers; α f is the vector rudder angle control quantity of the front group of propellers; and α r is the angle control quantity of the rear group of vector rudders.

[0100] Further, changing the position and attitude of the multi-mode mobile robot comprises:

[0101] After obtaining the aerodynamic force control quantity of each group of propellers and the angle control quantity of the vector rudder, the control instruction is converted and input into the driving element to control the driving element to generate corresponding actions, thereby changing the position and attitude of the multi-mode mobile robot.

[0102] Further, under the condition of relying only on attitude angle feedback, the step transition process is realized through the hybrid architecture of open-loop position control and closed-loop attitude control.

[0103] The above steps constitute a control method for the step transition process of a multi-mode mobile robot. The steps of applying the control method to a multi-mode mobile robot system are:

[0104] (1) The control system is written into a control algorithm.

[0105] (2) The initial state of the wall-to-step transition process of the multi-mode mobile robot is manipulated.

[0106] (3) An open-loop instruction is sent, which is converted into a control quantity and input into a control system to generate a control instruction through the control system, so that the robot tracks the planned posture trajectory and moves in position, and the step transition process is completed.

[0107] In order to more clearly express the technical solutions of the present application, specific embodiments are provided below to introduce the solutions:

[0108] The embodiment provides a wall-to-step transition motion process control method of a multi-mode mobile robot, and the flow of the control method is as shown in Figure 1 , and specifically includes:

[0109] Step 1: Establishing a dynamic model of the step transition process of the multi-mode mobile robot. The effect of the size of the aerodynamic force generated by the propeller and the rotation angle of the vector rudder on the center of mass of the multi-mode mobile robot is analyzed. In the step transition process, the center of mass of the multi-mode mobile robot moves horizontally and vertically, and rotates in the direction perpendicular to the horizontal direction. The horizontal direction is defined as the Y axis, the vertical direction is defined as the Z axis, and the direction perpendicular to the horizontal direction is defined as the X axis. The rotation angle around the X axis is defined as the roll angle

[0110] The establishment of the coordinate system and the mechanical analysis of the step transition process of the multi-mode mobile robot are as shown in Figure 4 , and the dynamic model of the multi-mode mobile robot obtained based on the Newton-Euler method is as follows:

[0111]

[0112] In the formula, are the accelerations of the center of mass of the multi-mode mobile robot in the Y and Z directions, respectively; is the angular and angular acceleration of the roll angle of the center of mass of the multi-mode mobile robot; F af , F ar are the aerodynamic forces generated by the front and rear groups of propellers of the multi-mode mobile robot, respectively; α f , α r are the angles of the front and rear vector rudders of the multi-mode mobile robot, respectively; I x is the moment of inertia of the center of mass of the multi-mode mobile robot around the X axis; l af , l ar are the vertical distances from the centers of the two groups of propellers of the multi-mode mobile robot to the center of mass; N Z , M N are unknown environmental constraint forces and constraint moments generated thereby.

[0113] Step 2: The posture angle trajectory planning of the step transition process of the multi-mode mobile robot is performed. By analyzing the step transition process of the multi-mode mobile robot, the expected motion process of the step transition state of the multi-mode mobile robot can be obtained, as shown in Figure 5 .

[0114] The multi-mode mobile robot is suspended by the front wheels on the water platform as the initial state of the step transition process. During the motion process of the step transition, the rear wheels of the multi-mode mobile robot are gradually lifted by relying on the change of the size and direction of the aerodynamic force, and at the same time, the front wheels move forward, so that the rear wheels and the front wheels of the multi-mode mobile robot are finally moved to the water platform, completing the step transition process.

[0115] Since the initial position and the final position of the step transition process of the multi-mode mobile robot are fixed, the trajectory of the step transition process of the multi-mode mobile robot is planned.

[0116] Since the sensor resources carried by the multi-mode mobile robot in this embodiment are limited, the multi-mode mobile robot can only obtain real-time feedback of the posture angle, so only the trajectory planning of the posture angle change of the step transition process of the multi-mode mobile robot is performed. Through simulation and experiment, it can be known that the roll angle of the initial state of the step transition process of the multi-mode mobile robot in this embodiment is about 74 degrees, and the roll angle of the final state should be 0 degrees. The trajectory planning result based on the B-spline interpolation method is shown in Figure 6 .

[0117] Step 3: The result of the posture angle trajectory planning of the step transition process of the multi-mode mobile robot is preset as a target quantity in the controller. After planning the posture angle trajectory of the step transition process of the multi-mode mobile robot, it is preset as a control target quantity in the control system, so that the control system realizes trajectory tracking control.

[0118] Step 4: The posture angle controller of the step transition process of the multi-mode mobile robot is designed. Based on the posture angle dynamics equation and the adaptive sliding mode control method, the posture angle controller of the step transition process of the multi-mode mobile robot is designed.

[0119] The posture angle dynamics equation in the dynamics model is expressed as a dynamics equation related to the control output. The control output of the posture angle controller of the multi-mode mobile robot is the moment M of the virtual control quantity generated by the aerodynamic force at the center of mass, and the dynamics equation related to the control output is as follows:

[0120]

[0121] The sliding mode surface equation is designed as follows:

[0122]

[0123] where c is a sliding surface design parameter; is the error value of the roll angle and the error value of the angular velocity of the multi-mode mobile robot.

[0124] The adaptive sliding mode control law equation is as follows:

[0125]

[0126] where M is the closed-loop control output of the attitude controller; is the expected angular acceleration of the roll angle at the center of mass of the multi-mode mobile robot; ε is an equal-speed reaching law parameter, which is a normal number; is the estimated value of the environmental constraint torque; sgn(s) is a function about the sliding surface s, s>0 makes sgn(s)=1, and s<0 makes sgn(s)=-1.

[0127] The adaptive estimation law equation of the environmental constraint torque is as follows:

[0128]

[0129] The Lyapunov function is constructed as follows:

[0130]

[0131] The designed sliding mode control law and adaptive estimation law satisfy V≥0 and V≤0, so the control is stable.

[0132] The attitude controller of the multi-mode mobile robot can be designed through the adaptive sliding mode control law and the estimation law of the environmental constraint torque, to realize the attitude trajectory tracking control of the multi-mode mobile robot.

[0133] Specifically, the sliding mode variable structure control of the multi-mode mobile robot needs to combine its dynamics equation, according to formula (1), the roll angle dynamics equation in the window transition process of the multi-mode mobile robot is as shown in formula (7):

[0134]

[0135] Since the torque generated by the driving element is the controlled quantity, the roll angle dynamics equation of the multi-mode mobile robot can be simplified, and F af cosα f l af -F ar cosα r l ar =M, and the simplified result is as shown in formula (8).

[0136]

[0137] wherein M is the closed-loop control output of the attitude controller.

[0138] Since the roll angle dynamics equation of the multi-mode mobile robot contains the constraint torque M generated by the unknown environmental constraint force N , in order to improve the robustness of the attitude control of the multi-mode mobile robot, an adaptive sliding mode variable structure control method is adopted to design the estimation law of M N to realize the control of the multi-mode mobile robot.

[0139] The dynamics model of the multi-mode mobile robot is a second-order model, and the sliding mode surface is designed as shown in equation (9):

[0140]

[0141] Taking the derivative of equation (9) can obtain as shown in equation (10).

[0142]

[0143] Substituting into equation (10) can obtain equation (11).

[0144]

[0145] In the equation, is the angular acceleration error of the roll angle at the center of mass of the multi-mode mobile robot, is the expected angular acceleration of the roll angle at the center of mass of the multi-mode mobile robot, is the actual angular acceleration of the roll angle at the center of mass of the multi-mode mobile robot.

[0146] The sliding mode control law is designed using the constant rate approach law, as shown in equation (12).

[0147]

[0148] Equations (8), (11) and (12) are combined to obtain the sliding mode control law of the roll angle, as shown in equation (13).

[0149]

[0150] Define as shown in equation (14).

[0151]

[0152] wherein is the error between the actual value of the environmental torque and the estimated value of the environmental torque.

[0153] Use Instead of M in formula (13) N , formula (15) can be obtained.

[0154]

[0155] Design M N The estimation law is shown in formula (16).

[0156]

[0157] Construct Lyapunov function as shown in formula (17), and derive it as shown in formula (18).

[0158]

[0159] Where the unknown environmental constraint moment M N is a constant, so Therefore Can be written as Therefore, formula (18) can also be written as formula (19).

[0160]

[0161] Bring formula (15), formula (16) into formula (19), formula (20) can be obtained.

[0162]

[0163] According to the Lyapunov function, the designed adaptive sliding mode control law and estimation law satisfy V≥0 and V≤0, so the control system is stable.

[0164] Step 5: Design a hybrid controller to combine the open-loop control amount and the closed-loop control amount, output the control amount decoupling value of the driving element, and further calculate and convert it into the control command of the driving element. Through the dynamic regulation and control of the hybrid controller, the multiple driving elements of the multi-mode mobile robot are controlled.

[0165] Design a hybrid controller based on pseudo-inverse method, the equation is as follows:

[0166]

[0167] In the formula, F yf , F yr , F zf , F zr are the y-axis and z-axis component control amounts of the aerodynamic force generated by the front and rear two groups of propellers of the multi-mode mobile robot; F y , F z are the open-loop control amounts input by the remote controller; M is the closed-loop control amount output by the attitude controller.

[0168] Step 6: The virtual control quantity output by the hybrid controller is converted into a driving element control instruction, which is input into the driving element to control it to generate corresponding movement, thereby changing the position and posture of the multi-mode mobile robot and completing the step transition process.

[0169] The y-axis and z-axis component control quantities of the aerodynamic forces generated by the front and rear two groups of propellers output by the hybrid controller are further converted to obtain the driving element control quantity, and the conversion equation is as follows:

[0170]

[0171] In the formula, F af is the aerodynamic force control quantity of the front group of propellers; F ar is the aerodynamic force control quantity of the rear group of propellers; a f is the vector rudder angle control quantity of the front group of propellers; a r is the angle control quantity of the rear group of vector rudders.

[0172] After obtaining the aerodynamic force control quantity and the angle control quantity of the vector rudder of each group of propellers, they are converted into control instructions and input into the driving element to control the driving element to generate corresponding actions, so that the position and posture of the multi-mode mobile robot can be changed to realize the step transition process.

[0173] The hybrid control system flow of the step transition process of the multi-mode mobile robot based on open-loop control and closed-loop control is shown in Figure 2 . Among them, the expected value of the roll angle is the attitude angle trajectory planning result in step 2; the controller is the attitude closed-loop controller based on adaptive sliding mode control in step 4; the hybrid power distribution is the hybrid controller designed based on the pseudo-inverse method in step 5; the aerodynamic force and vector rudder angle calculation is based on the conversion equation in step 6, which converts the y-axis and z-axis component control quantities of the aerodynamic forces generated by the front and rear two groups of propellers output by the hybrid controller into the control instructions of the aerodynamic force and the vector rudder angle.

[0174] This embodiment lists the application flow of a control method for the step transition process of a multi-mode mobile robot in a multi-mode mobile robot system, as shown in Figure 3 . The application flow of the control method in the multi-mode mobile robot system includes:

[0175] According to the control system architecture shown in Figure 3 , the corresponding control algorithm is written.

[0176] The multi-mode mobile robot is controlled to reach the initial state of the step transition process, i.e., the state that the front wheels are suspended on the water platform surface.

[0177] The open-loop instruction is sent to generate a control instruction through a control system to control the aerodynamic force provided by the propeller and the angle of rotation of the rudder machine, so that the robot tracks the planned posture trajectory and moves at the same time to complete the step transition process.

[0178] In this embodiment, the posture angle trajectory tracking simulation results of the step transition process of the multi-mode mobile robot are as shown in Figure 7 Figure 7 It can be seen that when the control method proposed in this embodiment is used to control the step transition process of the multi-mode mobile robot, the posture angle can track the planned posture angle expected trajectory in real time.

[0179] The center of mass movement trajectory simulation results of the step transition process of the multi-mode mobile robot are as shown in Figure 8 Figure 8 It can be seen that by combining the hybrid control method of open-loop control and closed-loop control, the center of mass of the multi-mode mobile robot can be controlled, and finally the step transition process of the multi-mode mobile robot is realized. Figure 8 The center of mass trajectory of the multi-mode mobile robot in the above figure can be divided into two segments, the first segment of the curve trajectory is the step transition process of the multi-mode mobile robot, and the second segment of the straight line trajectory is the multi-mode mobile robot completing the step transition process, and then switching to the ground moving mode and continuing to move forward for a distance.

[0180] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.​​

Claims

1. A method for controlling the transition motion of a multi-mode mobile robot over a wall staircase, characterized in that, include: Based on changing environmental constraints, a dynamic model of the step transition process of a multi-mode mobile robot is constructed. The step transition process of the multi-mode mobile robot is analyzed, the attitude angle trajectory of the multi-mode mobile robot transition process is planned, and the attitude angle trajectory planning result is used as the control target quantity of the multi-mode mobile robot and input into the controller to realize the trajectory tracking control of the attitude angle. An attitude angle controller for a multi-mode mobile robot with a step transition process based on adaptive sliding mode control is designed, and a hybrid controller is designed based on the open-loop control quantity of position and the closed-loop control quantity of attitude. The virtual control quantity output by the mixer is converted into control commands for the drive element, which are then input into the drive element to generate corresponding motion, thereby changing the position and posture of the multi-mode mobile robot and completing the step transition process. A hybrid controller is designed based on the position open-loop control quantity and the attitude closed-loop control quantity, including: The attitude control quantity generated by the attitude closed-loop controller is combined with the open-loop control quantity converted from the open-loop remote control command. The power is distributed through the mixer. The distributed command is converted into a control command and transmitted into the drive element, ultimately controlling the multi-mode mobile robot to generate motion. The mixer equation is as follows: ， In the formula, , , , These are the components of the aerodynamic force generated by the front and rear propellers of the multi-mode mobile robot along the y-axis and z-axis, respectively. , All are open-loop control quantities input by the remote control; This is the closed-loop control quantity output by the attitude controller; , These are the vertical distances from the center of the two propellers to the center of mass of the multi-mode mobile robot.

2. The method for controlling the transition motion of a multi-mode mobile robot on a wall step according to claim 1, characterized in that, The dynamic model of the step transition process of the multi-mode mobile robot is as follows: ， In the formula, , These are the accelerations in the Y and Z directions at the center of mass of the multi-mode mobile robot, respectively. , These are the roll angle and angular acceleration at the center of mass of the multi-mode mobile robot, respectively. , These are the aerodynamic forces generated by the front and rear propellers of the multi-mode mobile robot, respectively. , These represent the angles of the front and rear vector servos of the multi-mode mobile robot; Let be the rotational inertia about the X-axis at the center of mass of the multi-mode mobile robot; , These are the vertical distances from the center of the two propellers of the multi-mode mobile robot to its center of mass, respectively. , These are the unknown environmental constraints and the constraint torques they generate.

3. The method for controlling the transition motion of a multi-mode mobile robot on a wall step according to claim 1, characterized in that, Performing attitude angle trajectory planning for the transition process of the multi-mode mobile robot includes: Based on the initial and final roll angles of the step transition process, B-spline interpolation is performed to obtain the attitude angle trajectory planning results.

4. The method for controlling the transition motion of a multi-mode mobile robot on a wall step according to claim 3, characterized in that, During the transition to the steps, the multi-mode mobile robot starts with its front wheels suspended on the horizontal platform and its rear wheels in contact with the vertical wall. The multi-mode mobile robot terminates with both wheels on the horizontal platform.

5. The method for controlling the transition motion of a multi-mode mobile robot on a wall step according to claim 1, characterized in that, An attitude angle controller for a multi-mode mobile robot's step transition process based on adaptive sliding mode control is designed, including: Define the sliding surface; Based on the sliding surface, an adaptive sliding mode control law and an adaptive estimation law for environmental constraint torques are designed respectively. Based on the adaptive sliding mode control law and the adaptive estimation law of environmental constraint torques, a Lyapunov function V is constructed. If the Lyapunov function V satisfies... and If the control is stable, then the control is stable; among them, It is the derivative of Lyapunov.

6. The method for controlling the transition motion of a multi-mode mobile robot on a wall step according to claim 5, characterized in that, The sliding surface is: ， In the formula, c is the design parameter of the sliding surface; , These represent the error values ​​for the roll angle and angular velocity of the multi-mode mobile robot, respectively. It is a sliding surface; The adaptive sliding mode control law is as follows: ， In the formula, This is the closed-loop control quantity output by the attitude controller; The desired angular acceleration for the roll angle at the center of mass of the multi-mode mobile robot; These are the parameters of the isotropic reaching law; This is an estimate of the environmental constraint torque; Let be the rotational inertia about the X-axis at the center of mass of the multi-mode mobile robot; Let sgn(s) be a function of the sliding surface s, where s>0 and sgn(s)=1, and s<0 and sgn(s)=-1. The adaptive estimation law for the environmental constraint torque is: ， In the formula, An adaptive estimation law for environmental constraint torques; The Lyapunov function V is: ， In the formula, This represents the error between the actual value and the estimated value of the environmental torque.

7. The method for controlling the transition motion of a multi-mode mobile robot on a wall step according to claim 1, characterized in that, The virtual control quantity output by the mixer is converted into the control quantity of the drive element as follows: ， In the formula, This is the aerodynamic control quantity for the previous set of propellers; This is the aerodynamic control quantity for the next set of propellers; This is the vector servo angle control value for the previous set of propellers; This is the angle control value for the next set of vector servos.

8. The method for controlling the transition motion of a multi-mode mobile robot on a wall step according to claim 7, characterized in that, Changing the position and orientation of the multi-mode mobile robot includes: After obtaining the aerodynamic control quantities of each propeller group and the angular control quantities of the vector servo motor, they are converted into control commands and input into the drive element. The drive element is then controlled to produce corresponding actions, thereby changing the position and attitude of the multi-mode mobile robot.

9. The method for controlling the transition motion of a multi-mode mobile robot on a wall step according to any one of claims 1-8, characterized in that, Under conditions where only attitude angle feedback is relied upon, the multi-mode mobile robot achieves the step transition process through a hybrid architecture of open-loop position control and closed-loop attitude control.

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