Wall surface step transition motion process control method of multi-mode mobile robot

Abstract

The invention discloses a wall surface step transition motion process control method for a multi-mode mobile robot, and the method comprises the steps: constructing a kinetic equation of a step transition process of the multi-mode mobile robot based on changing environmental constraints; the transition process is analyzed, attitude angle trajectory planning of the transition process of the multi-mode mobile robot is carried out, an attitude angle trajectory planning result is used as a control target quantity to be input into a controller, and trajectory tracking control of an attitude angle is achieved; designing an attitude angle controller in the step transition process of the multi-mode mobile robot based on self-adaptive sliding mode control, and designing a hybrid controller according to the position open-loop control quantity and the attitude closed-loop control quantity; and the virtual control quantity output by the hybrid controller is converted into a driving element control instruction, and the driving element control instruction is input into a driving element to generate corresponding motion, so that the position and the posture of the multi-mode mobile robot are changed, and step transition is completed. The step transition process of the multi-mode mobile robot can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of mobile robots, and in particular to a method for controlling a wall-step transition motion process of a multi-mode mobile robot. Background Art

[0002] Mobile robots have long been a research hotspot in the field of robotics, having been maturely applied in fields such as industrial production, logistics and transportation, and military reconnaissance, fulfilling corresponding tasks. As research deepens, mobile robots need to break through the limitations of a single motion mode and possess multimodal motion capabilities to cope with complex operating environments and diverse tasks. Consequently, multimodal mobile robot systems have emerged. Because multimodal mobile robots significantly expand their workspace, enabling them to adapt to more complex working environments while also providing greater flexibility, they possess broad application prospects and enormous development potential.

[0003] A multimodal mobile robot refers to a mobile robot with multiple motion modes. By integrating multiple motion mechanisms and coordinating control strategies for different scenarios, it can achieve flexible movement in different terrains by switching motion modes. For example, there are wheel-leg multimodal mobile robots, wheel-track multimodal mobile robots, flying-ground multimodal mobile robots, ground-underwater multimodal mobile robots, and ground-wall-climbing multimodal mobile robots. The control method proposed in this invention is mainly aimed at a multimodal robot that can achieve ground and wall motion.

[0004] Domestic research on control methods based on wall-climbing robots has published patents including: a wall-climbing robot control method, device, equipment and storage medium, a wall-climbing robot control method, etc.; similar research abroad includes: the VertiGo robot of the Swiss Federal Institute of Technology in Zurich.

[0005] Current research and technology focuses on solving the problem of stable wall-climbing control for robots on relatively flat walls. However, in practice, wall-climbing robots often experience motion similar to climbing stairs when climbing vertical walls. For example, when climbing from a vertical wall to a horizontal platform, the robot needs to flip 90° from the vertical climbing state to the horizontal motion state. Existing multi-mode wall-climbing robots have not yet solved this problem. The transition from a vertical wall to a horizontal platform requires a significant change in the position and posture of the multi-mode mobile robot. This process places higher demands on the robot's stable control and requires a targeted motion control strategy. Summary of the Invention

[0006] In order to solve the technical problems existing in the above-mentioned prior art, the present invention proposes a wall-step transition motion process control method for a multi-mode mobile robot. The control method is based on a hybrid control method combining open-loop control and closed-loop posture control, so that the multi-mode mobile robot can realize the transition motion from climbing over a vertical wall to a horizontal step.

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

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

[0009] Analyzing the step transition process of the multi-mode mobile robot, performing attitude angle trajectory planning for the multi-mode mobile robot during the transition process, and inputting the attitude angle trajectory planning result into the controller as the control target quantity of the multi-mode mobile robot to achieve attitude angle trajectory tracking control;

[0010] Design an attitude angle controller for a multi-mode mobile robot during step transition based on adaptive sliding mode control, and design a mixer based on the position open-loop control variable and the attitude closed-loop control variable.

[0011] The virtual control quantity output by the mixer is converted into a drive element control instruction, which is input into the drive element to generate corresponding movement, 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:

[0013]

[0014] Where, are the accelerations in the Y and Z directions at the center of mass of the multi-modal mobile robot, respectively; are the roll angle and angular acceleration of the multi-modal mobile robot at the center of mass; F af 、F ar are the aerodynamic forces generated by the front and rear propellers of the multi-mode mobile robot; α f , α r are the angles of the front and rear vector servos of the multi-mode mobile robot; I x is the moment of inertia of the multimodal 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 propellers to the center of mass of the multi-mode mobile robot; N Z 、M N are the unknown environmental constraint force and the constraint torque it generates, respectively.

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

[0016] According to the roll angles at the initial and final states of the step transition process, B-spline interpolation processing is performed to obtain the attitude angle trajectory planning results.

[0017] Preferably, during the step transition process, the starting state of the multi-mode mobile robot is that the front wheels are suspended on the horizontal surface and the rear wheels contact the vertical wall, and the ending state of the multi-mode mobile robot is that both wheels are on the horizontal surface.

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

[0019] Define the sliding surface;

[0020] Based on the sliding mode 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. If the Lyapunov function V satisfies V≥0 and Then the control is stable; is Lyapunov's derivative.

[0022] Preferably, the sliding surface is:

[0023]

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

[0025] The adaptive sliding mode control law is:

[0026]

[0027] Where M is the closed-loop control quantity output by the attitude controller; is the expected angular acceleration of the roll angle at the center of mass of the multimodal mobile robot; ε is the parameter of the constant velocity reaching law; is the estimated value of the environmental constraint torque; I x is the moment of inertia of the multimodal mobile robot around the X-axis at the center of mass; sgn(s) is a function of the sliding surface s, when s>0, sgn(s)=1, when s<0, sgn(s)=-1;

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

[0029]

[0030] Where, is the adaptive estimation law for the environmental constraint torque;

[0031] The Lyapunov function V is:

[0032]

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

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

[0035] The attitude control variable generated by the attitude closed-loop controller is combined with the open-loop control variable 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 to the drive element, ultimately controlling the multi-mode mobile robot to produce movement.

[0036] Wherein, the mixer equation is:

[0037]

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

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

[0040]

[0041] Where, F af is the aerodynamic control quantity of the first set of propellers; F ar is the aerodynamic control quantity of the rear set of propellers; α f is the vector servo angle control value of the first set of propellers; α r It is the angle control value of the latter set of vector servos.

[0042] Preferably, changing the position and posture of the multimodal mobile robot comprises:

[0043] After obtaining the aerodynamic control quantity of each set of propellers and the angle control quantity of the vector servo, they are converted into control instructions and input into the drive elements, which control the drive elements to produce corresponding actions, thereby changing the position and posture of the multi-mode mobile robot.

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

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

[0046] (1) The present invention proposes a control method for a multi-mode mobile robot's wall-step transition motion process. This control method can realize the step transition process of the multi-mode mobile robot. That is, by controlling the rotation speed of the propeller carried by the multi-mode mobile robot and the angle of the vector servo, the magnitude and vector direction of the aerodynamic force generated thereby are controlled, thereby controlling the movement of the multi-mode mobile robot's position and the change of its posture, and completing the step transition process of the multi-mode mobile robot from a vertical wall to a horizontal platform.

[0047] (2) Based on a hybrid control method that combines open-loop control with closed-loop control, the propeller and vector servo carried by the multi-mode mobile robot are dynamically adjusted through the mixer, so that the multi-mode mobile robot can complete the step transition process without exceeding the physical limitations. This solves the control problem of the multi-mode mobile robot step transition process that does not rely on global state feedback when the sensor resources carried by the multi-mode mobile robot system are limited. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

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

[0050] Figure 2 Schematic diagram of the control process of the step transition process of the multi-mode mobile robot according to an embodiment of the present invention;

[0051] Figure 3 This is a flowchart of an application of a method for controlling a wall-step transition motion process of a multi-mode mobile robot according to an embodiment of the present invention;

[0052] Figure 4 The coordinate system for the step transition process of the multi-mode mobile robot according to an embodiment of the present invention is established on the mechanical analysis diagram;

[0053] Figure 5 Schematic diagram of the expected motion process of a multi-mode mobile robot step transition according to an embodiment of the present invention;

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

[0055] Figure 7 Schematic diagram of the simulation results of the posture angle trajectory tracking during the step transition process of the multi-mode mobile robot according to an embodiment of the present invention;

[0056] Figure 8 This is a schematic diagram of the simulation results of the center of mass trajectory of the multi-mode mobile robot during the step transition process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0057] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. 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 flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0059] This embodiment proposes a method for controlling the wall-step transition motion process of a multi-mode mobile robot. Figure 1 ,include:

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

[0061] Analyzing the step transition process of the multi-mode mobile robot, performing attitude angle trajectory planning for the multi-mode mobile robot during the transition process, and inputting the attitude angle trajectory planning result into the controller as the control target quantity of the multi-mode mobile robot to achieve attitude angle trajectory tracking control;

[0062] Design an attitude angle controller for a multi-mode mobile robot during step transition based on adaptive sliding mode control, and design a mixer based on the position open-loop control variable and the attitude closed-loop control variable.

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

[0064] Specifically, this embodiment is directed to a wheeled multi-mode mobile robot propelled by rotor aerodynamics, and proposes a transition motion control method that enables it to smoothly climb from a vertical wall to a horizontal step. The robot has a passive wheeled motion mechanism and, through a four-rotor propulsion system capable of adjusting the direction of the aerodynamic force vector, enables it to move freely on both the ground and walls. In ground movement mode, the multi-mode mobile robot can control the angle of the vector servo to change the direction of the aerodynamic force vector generated by the propeller to provide the driving force required for the multi-mode mobile robot to move, thereby achieving the movement of the multi-mode mobile robot on flat ground. In wall climbing movement 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 required compression force for the multi-mode mobile robot to climb the wall and the driving force for movement on the wall, thereby achieving the movement of the multi-mode mobile robot to climb the wall.

[0065] The multimodal mobile robot is equipped with four propellers and two vector servos as drive elements. The aerodynamic force generated by each propeller can be independently controlled. The propellers are grouped in pairs along the vehicle's front, with each pair connected to a vector servo. The vector direction of the aerodynamic force generated by the two propellers can be independently adjusted by controlling the angles of the front and rear vector servos. By controlling the magnitude and vector direction of the aerodynamic force generated by the propellers, the multimodal mobile robot's roll angle and position along the Y and Z axes can be changed, allowing the multimodal mobile robot to climb over a protruding wall corner and move from a vertical wall to a horizontal surface.

[0066] In response to the task requirement that the robot needs to perform step climbing during the process of wall climbing, this embodiment provides a transition motion process control method for a multi-mode mobile robot to climb over steps on a wall surface, which can enable the multi-mode mobile robot to smoothly climb from a vertical wall to a horizontal surface and complete the wall step climbing action process.

[0067] Furthermore, the effect of the aerodynamic force generated by the propeller and the rotation angle of the vector servo 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 perpendicular to the horizontal direction. The horizontal direction is defined as the Y-axis, the vertical direction as the Z-axis, the direction perpendicular to the horizontal direction as the X-axis, and the angle of rotation around the X-axis as the roll angle. The establishment of coordinate system and mechanical analysis of step transition process of multi-mode mobile robot are as follows Figure 4 shown.

[0068] The dynamic model of the multi-modal mobile robot based on the Newton-Euler method is as follows:

[0069]

[0070] Where, are the accelerations in the Y and Z directions at the center of mass of the multi-modal mobile robot, respectively; are the roll angle and angular acceleration of the multi-modal mobile robot at the center of mass; F af 、F ar are the aerodynamic forces generated by the front and rear propellers of the multi-mode mobile robot; α f , α r are the angles of the front and rear vector servos of the multi-mode mobile robot; I x is the moment of inertia of the multimodal 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 propellers to the center of mass of the multi-mode mobile robot; N Z 、M N are the unknown environmental constraint force and the constraint torque it generates, respectively.

[0071] Furthermore, the posture angle trajectory planning of the multi-mode mobile robot during the transition process is performed, including:

[0072] According to the roll angles at the initial and final states of the step transition process, B-spline interpolation processing is performed to obtain the attitude angle trajectory planning results.

[0073] Specifically, the multimodal mobile robot's step transition process begins with its front wheels suspended above a horizontal surface, with the robot tilted and resting on a convex corner of a wall. The robot ends with both wheels resting on the horizontal surface. The starting and ending positions of the entire step transition process are fixed. The initial attitude angle of the multimodal mobile robot is measured experimentally or through simulation, with the ending attitude angle being 0 degrees. These initial and ending positions are used to plan the trajectory of the multimodal mobile robot's attitude angle.

[0074] During the step transition process, the starting state is that the front wheels of the multi-mode mobile robot are suspended on the horizontal platform and the rear wheels touch the vertical wall, and the ending state is that both wheels of the multi-mode mobile robot are on the horizontal platform.

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

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

[0077] Define the sliding surface;

[0078] Based on the sliding mode 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 environmental 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; is Lyapunov's derivative.

[0080] Specifically, the sliding surface is:

[0081]

[0082] Where c is the design parameter of the sliding surface; are the error values ​​of the roll angle and angular velocity of the multi-mode mobile robot, respectively, and s is the sliding surface;

[0083] The adaptive sliding mode control law is:

[0084]

[0085] Where M is the closed-loop control quantity output by the attitude controller; is the expected angular acceleration of the roll angle at the center of mass of the multimodal mobile robot; ε is the parameter of the constant velocity reaching law; is the estimated value of the environmental constraint torque; I x is the moment of inertia of the multimodal mobile robot around the X-axis at the center of mass; sgn(s) is a function of the sliding surface s, when s>0, sgn(s)=1, when s<0, sgn(s)=-1;

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

[0087]

[0088] Where, is the adaptive estimation law for the environmental constraint torque;

[0089] The Lyapunov function V is:

[0090]

[0091] Where, is the error between the actual value of the environmental torque and the estimated value of the environmental torque, which is calculated as follows:

[0092] Furthermore, a mixer is designed based on the position open-loop control quantity and the attitude closed-loop control quantity, including:

[0093] The attitude control variable generated by the attitude closed-loop controller is combined with the open-loop control variable 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 to the drive element, ultimately controlling the multi-mode mobile robot to produce movement.

[0094] The mixer equation is:

[0095]

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

[0097] Furthermore, the virtual control quantity output by the mixer is converted into the control quantity of the driving element as follows:

[0098]

[0099] Where, F af is the aerodynamic control quantity of the first set of propellers; F ar is the aerodynamic control quantity of the rear set of propellers; α f is the vector servo angle control value of the first set of propellers; α r It is the angle control value of the latter set of vector servos.

[0100] Furthermore, changing the position and posture of the multimodal mobile robot includes:

[0101] After obtaining the aerodynamic control quantity of each set of propellers and the angle control quantity of the vector servo, they are converted into control instructions and input into the drive elements, which control the drive elements to produce corresponding actions, thereby changing the position and posture of the multi-mode mobile robot.

[0102] Furthermore, under the condition of relying solely on attitude angle feedback, the step transition process is achieved through a 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 for applying this control method to a multi-mode mobile robot system are as follows:

[0104] (1) Write the control system into a control algorithm.

[0105] (2) Manipulate the initial state of the multimodal mobile robot's transition process from the wall to the step.

[0106] (3) Send open-loop instructions, convert them into control quantities and input them into the control system. The control system generates control instructions to control the aerodynamic force provided by the propeller and the angle of rotation of the vector servo, so that the robot can track the planned posture trajectory and move its position at the same time to complete the step transition process.

[0107] In order to more clearly express the technical solution of the present invention, the following specific embodiments are provided to introduce the solution:

[0108] This embodiment proposes a method for controlling the wall-step transition motion process of a multi-mode mobile robot. The process of the control method is as follows: Figure 1 As shown, specifically including:

[0109] Step 1: Establish a dynamic model for the step transition process of the multi-mode mobile robot. Analyze the effect of the aerodynamic force generated by the propeller and the rotation angle of the vector servo on the center of mass of the multi-mode mobile robot. During the step transition process, the center of mass of the multi-mode mobile robot moves horizontally and vertically, and rotates perpendicular to the horizontal direction. Define the horizontal direction as the Y-axis, the vertical direction as the Z-axis, the direction perpendicular to the horizontal direction as the X-axis, and the angle of rotation around the X-axis as the roll angle.

[0110] The establishment of coordinate system and mechanical analysis of step transition process of multi-mode mobile robot are as follows Figure 4 As shown in Figure 2, the dynamic model of the multi-mode mobile robot based on the Newton-Euler method is as follows:

[0111]

[0112] Where, are the accelerations in the Y and Z directions at the center of mass of the multi-modal mobile robot, respectively; is the rolling angle and angular acceleration of the multimodal mobile robot at the center of mass; F af 、F ar are the aerodynamic forces generated by the front and rear propellers of the multi-mode mobile robot; α f , α r are the angles of the front and rear vector servos of the multi-mode mobile robot; I x is the moment of inertia of the multimodal 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 propellers to the center of mass of the multi-mode mobile robot; N Z 、M N is the unknown environmental constraint force and the constraint torque it generates.

[0113] Step 2: Plan the posture angle trajectory of the multi-mode mobile robot during the step transition process. By analyzing the step transition process of the multi-mode mobile robot, the desired motion process of the multi-mode mobile robot during the step transition state can be obtained, such as Figure 5 shown.

[0114] The multimodal mobile robot starts with its front wheels suspended on a horizontal platform. During the step transition, the rear wheels of the multimodal mobile robot are gradually lifted up by changes in the size and direction of the aerodynamic force, while the front wheels move forward. Ultimately, both the rear and front wheels of the multimodal mobile robot are moved to the horizontal platform, completing the step transition process.

[0115] Since the initial position and the terminal position of the multi-mode mobile robot during the step transition process are fixed, trajectory planning is performed for the multi-mode mobile robot during the step transition process to plan the trajectory of the multi-mode mobile robot during the step transition process.

[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 on the attitude angle. Therefore, trajectory planning is only performed for the attitude angle changes during the step transition process of the multi-mode mobile robot. Through simulation and experiments, it can be found that the initial state roll angle of the step transition process of the multi-mode mobile robot in this embodiment is about 74 degrees, and the final state roll angle should be 0 degrees. The trajectory planning results based on the B-spline interpolation method are shown in Figure 2. Figure 6 shown.

[0117] Step 3: The result of the multi-mode mobile robot's step transition posture angle trajectory planning is preset into the controller as a target quantity. After the multi-mode mobile robot's step transition posture angle trajectory is planned, it is preset into the control system as a control target quantity, enabling the control system to achieve trajectory tracking control.

[0118] Step 4: Design the attitude angle controller for the multi-mode mobile robot during the step transition process. Based on the attitude angle dynamics equation and the adaptive sliding mode control method, design the attitude angle controller for the multi-mode mobile robot during the step transition process.

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

[0120]

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

[0122]

[0123] Where c is the design parameter of the sliding surface; 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 quantity output by the attitude controller; is the expected angular acceleration of the roll angle at the center of mass of the multimodal mobile robot; ε is the parameter of the constant velocity reaching law, which is a positive constant; is the estimated value of the environmental constraint torque; sgn(s) is a function of the sliding surface s, s>0 makes sgn(s)=1, and s<0 makes sgn(s)=-1.

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

[0128]

[0129] Construct the Lyapunov function 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, which is used to realize the attitude trajectory tracking control of the multi-mode mobile robot.

[0133] Specifically, the sliding mode variable structure control of the multimodal mobile robot needs to be combined with its dynamic equations. According to equation (1), the dynamic equation of the roll angle during the window sill transition of the multimodal mobile robot is shown in equation (7):

[0134]

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

[0136]

[0137] Among them, M is the closed-loop control quantity output by the attitude controller.

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

[0139] The dynamic model of the multimodal mobile robot is a second-order model, and the designed sliding surface is shown in Equation (9):

[0140]

[0141] Taking the derivative of formula (9) we can get As shown in formula (10).

[0142]

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

[0144]

[0145] Where, 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 multimodal mobile robot, is the actual angular acceleration of the roll angle at the center of mass of the multimodal mobile robot.

[0146] The sliding mode control law is designed using the constant velocity reaching law, as shown in Equation (12).

[0147]

[0148] Combining Equations (8), (11), and (12), we can obtain the sliding mode control law of the roll angle, as shown in Equation (13).

[0149]

[0150] definition As shown in formula (14).

[0151]

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

[0153] use Substitute M in formula (13) N , we can get formula (15).

[0154]

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

[0156]

[0157] Construct the Lyapunov function as shown in Equation (17), and take its derivative as shown in Equation (18).

[0158]

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

[0160]

[0161] Substituting equations (15) and (16) into equation (19), we can obtain equation (20).

[0162]

[0163] It can be seen from the Lyapunov function that 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 mixer to combine the open-loop control variable and the closed-loop control variable, output the control variable decoupling value of the drive element, and further calculate and convert it into the control instruction of the drive element. The mixer is used to dynamically control the multiple drive elements of the multi-mode mobile robot.

[0165] The mixer is designed based on the pseudo-inverse method, and the equation is as follows:

[0166]

[0167] Where, F yf 、F yr 、F zf 、F zr are the control quantities of the aerodynamic forces generated by the front and rear propellers of the multi-mode mobile robot in the y-axis and z-axis components; F y 、F z is the open-loop control variable input by the remote controller; M is the closed-loop control variable output by the attitude controller.

[0168] Step 6: Convert the virtual control quantity output by the mixer into a drive element control instruction, input it into the drive element, and control it to produce corresponding movement, thereby changing the position and posture of the multi-mode mobile robot and completing the step transition process.

[0169] The control quantities of the aerodynamic forces generated by the front and rear propellers on the y-axis and z-axis output by the mixer can be further converted to the control quantities of the drive elements. The conversion equation is as follows:

[0170]

[0171] Where, F af is the aerodynamic control quantity of the first set of propellers; F ar is the aerodynamic control quantity of the rear set of propellers; α f is the vector servo angle control value of the first set of propellers; α r It is the angle control value of the latter set of vector servos.

[0172] After obtaining the aerodynamic control quantity of each set of propellers and the angle control quantity of the vector servo, they are converted into control instructions and input into the drive elements. By controlling the drive elements to produce corresponding actions, the position and posture of the multi-mode mobile robot can be changed to achieve a step transition process.

[0173] The hybrid control system process of the multi-mode mobile robot step transition process based on open-loop control and closed-loop control is as follows Figure 2 As shown. 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 mixed power distribution is the mixer designed based on the pseudo-inverse method in step 5; the aerodynamic force and vector servo angle calculation is based on the conversion equation in step 6, which converts the aerodynamic force generated by the front and rear propellers in the y-axis and z-axis components of the mixer into control instructions for the aerodynamic force and the vector servo angle.

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

[0175] according to Figure 3 The control system architecture is shown and the corresponding control algorithm is written.

[0176] Control the multimodal mobile robot to reach the initial state of the step transition process, that is, the state where the front wheels are suspended on the horizontal platform surface.

[0177] Send open-loop instructions, generate control instructions through the control system, control the aerodynamic force provided by the propeller and the rotation angle of the vector servo, so that the robot can track the planned posture trajectory and move at the same time to complete the step transition process.

[0178] In this embodiment, the simulation results of the posture angle trajectory tracking of the multi-mode mobile robot during the step transition process are as follows: Figure 7 As shown. 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 expected trajectory of the posture angle in real time.

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

[0180] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for controlling the wall-step transition motion process of a multi-mode mobile robot, characterized in that: include: Based on the changing environmental constraints, a dynamic model of the step transition process of a multi-modal mobile robot is constructed; Analyzing the step transition process of the multi-mode mobile robot, performing attitude angle trajectory planning for the multi-mode mobile robot during the transition process, and inputting the attitude angle trajectory planning result into the controller as the control target quantity of the multi-mode mobile robot to achieve attitude angle trajectory tracking control; Design an attitude angle controller for a multi-mode mobile robot during step transition based on adaptive sliding mode control, and design a mixer based on the position open-loop control variable and the attitude closed-loop control variable. The virtual control quantity output by the mixer is converted into a drive element control instruction, which is input into the drive element to generate corresponding movement, thereby changing the position and posture of the multi-mode mobile robot and completing the step transition process.

2. The method for controlling the wall-step transition motion process of a multi-mode mobile robot according to claim 1, characterized in that: The dynamic model of the step transition process of the multi-mode mobile robot is: Where, are the accelerations in the Y and Z directions at the center of mass of the multi-modal mobile robot, respectively; are the roll angle and angular acceleration of the multi-modal mobile robot at the center of mass; F af 、F ar are the aerodynamic forces generated by the front and rear propellers of the multi-mode mobile robot; α f , α r are the angles of the front and rear vector servos of the multi-mode mobile robot; I x is the moment of inertia of the multimodal 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 propellers to the center of mass of the multi-mode mobile robot; N Z 、M N are the unknown environmental constraint force and the constraint torque it generates, respectively.

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

4. The method for controlling the wall-step transition motion process of a multi-mode mobile robot according to claim 3, characterized in that: During the step transition process, the initial state of the multi-mode mobile robot is that the front wheels are suspended on the horizontal platform and the rear wheels contact the vertical wall, and the terminal state of the multi-mode mobile robot is that both wheels are on the horizontal platform.

5. The method for controlling the wall-step transition motion process of a multi-mode mobile robot according to claim 1, characterized in that: The attitude angle controller of the multi-mode mobile robot during step transition is designed based on adaptive sliding mode control, including: Define the sliding surface; Based on the sliding mode surface, an adaptive sliding mode control law and an environmental constraint torque adaptive estimation law are designed respectively; According to the adaptive sliding mode control law and the environmental constraint torque adaptive estimation law, a Lyapunov function V is constructed. If the Lyapunov function V satisfies V≥0 and V≤0, the control is stable; wherein V is the derivative of Lyapunov.

6. The method for controlling the wall-step transition motion process of a multi-mode mobile robot according to claim 5, characterized in that: The sliding surface is: Where c is the design parameter of the sliding surface; are the error values ​​of the roll angle and angular velocity of the multi-mode mobile robot, respectively, and s is the sliding surface; The adaptive sliding mode control law is: Where M is the closed-loop control quantity output by the attitude controller; is the expected angular acceleration of the roll angle at the center of mass of the multimodal mobile robot; ε is the parameter of the constant velocity reaching law; is the estimated value of the environmental constraint torque; I x is the moment of inertia of the multimodal mobile robot around the X-axis at the center of mass; sgn(s) is a function of the sliding surface s, when s>0, sgn(s)=1, when s<0, sgn(s)=-1; The environmental constraint torque adaptive estimation law is: Where, is the adaptive estimation law for the environmental constraint torque; The Lyapunov function V is: Where, is the error between the actual value of the environmental torque and the estimated value of the environmental torque.

7. The method for controlling the wall-step transition motion process of a multi-mode mobile robot according to claim 1, characterized in that: Designing a mixer according to the position open-loop control quantity and the attitude closed-loop control quantity includes: The attitude control variable generated by the attitude closed-loop controller is combined with the open-loop control variable 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 to the drive element, ultimately controlling the multi-mode mobile robot to produce movement. Wherein, the mixer equation is: Where, F yf 、F yr 、F zf 、F zr are the components of the aerodynamic force on the y-axis and z-axis generated by the front and rear propellers of the multi-mode mobile robot; F y 、F z are open-loop control quantities input by the remote controller; M is the closed-loop control quantity output by the attitude controller; l af 、l ar are the vertical distances from the centers of the two propellers to the center of mass of the multimodal mobile robot.

8. The method for controlling the wall-step transition motion process of a multi-mode mobile robot according to claim 7, characterized in that: The virtual control quantity output by the mixer is converted into the driving element control quantity: Where, F af is the aerodynamic control quantity of the first set of propellers; F ar is the aerodynamic control quantity of the rear set of propellers; α f is the vector servo angle control value of the first set of propellers; α r It is the angle control value of the latter set of vector servos.

9. The method for controlling the wall-step transition motion process of a multi-mode mobile robot according to claim 8, characterized in that: Changing the position and posture of the multimodal mobile robot includes: After obtaining the aerodynamic control quantity of each set of propellers and the angle control quantity of the vector servo, they are converted into control instructions and input into the drive elements, which control the drive elements to produce corresponding actions, thereby changing the position and posture of the multi-mode mobile robot.

10. The method for controlling the wall-step transition motion process of a multi-mode mobile robot according to any one of claims 1 to 9, characterized in that: Under the condition of relying only on attitude angle feedback, the multimodal mobile robot realizes the step transition process through a hybrid architecture of open-loop position control and closed-loop attitude control.

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