CN-119682897-B - Double-wheel robot with double-wheel driving and double-steering control and control method

CN119682897BCN 119682897 BCN119682897 BCN 119682897BCN-119682897-B

Abstract

The invention provides a double-wheel robot with double-wheel driving and double-steering control and a control method, wherein a guide rail sliding block mechanism which is arranged in the extending degree direction is arranged at the front end of a frame of a vehicle body module, a front trunk connecting plate is fixedly connected with a sliding block and has linear motion freedom, a rear trunk connecting plate is fixedly arranged at the rear end of the frame in the front-back position, a front motion module is connected to the front trunk connecting plate, the rear motion module is connected to the rear trunk connecting plate, the structure is consistent and comprises thighs, shanks and wheels respectively, and the double-wheel robot is configured to switch among three different configurations of a bicycle, a self-balancing vehicle and an oblique vehicle, wherein the oblique vehicle is used for connecting the configuration change between the bicycle and the balancing vehicle. The double-wheel robot and the control method can realize smooth switching of two configurations of the bicycle and the self-balancing vehicle, and solve the over-constraint problem caused by a redundant driver by introducing the structural deformation freedom degree of the double-wheel vehicle and the active control of the degree of freedom.

Inventors

WANG XUEFENG
SUN BOTIAN
Lang Qinglin
LI MINGHE

Assignees

北京大学

Dates

Publication Date: 20260505
Application Date: 20241023

Claims (4)

1. A two-wheeled robot control method with two-wheeled drive and two-wheeled steering control, the two-wheeled robot comprising: The vehicle body module comprises a vehicle frame (1), a front trunk connecting plate (2) and a rear trunk connecting plate (3), wherein a guide rail sliding block mechanism (11) which is arranged along the length direction is arranged at the front end of the vehicle frame (1), the front trunk connecting plate (2) is fixedly connected with a sliding block and has linear motion freedom degree, the rear trunk connecting plate (3) is fixedly arranged at the rear end of the vehicle frame (1) at the front and rear positions, the front motion module (41) and the rear motion module (42) are connected onto the front trunk connecting plate (2), and the rear motion module (42) is connected onto the rear trunk connecting plate (3), has consistent structure and comprises thighs (403), lower legs (405) and wheels (407) respectively; the two-wheeled robot is configured to switch between three different modes of motion of a bicycle, a self-balancing cart, and an oblique cart, wherein the oblique cart is used to engage the mode switch between the bicycle and the balancing cart; The method is characterized in that: Establishing a two-wheeled vehicle coordinate system, comprising respectively recording angles of thighs (403) and calves (405) of a front movement module (41) relative to an axis of a hip rotating motor (401) as The rear movement module (42) is During the movement, the four angles are kept at fixed angles The axis extension lines of the front and rear hip rotating motors (401) respectively pass through the centers of the front and rear hub motors (406), and the extension distance is kept as The thigh (403) and the shank (405) are formed as a rigid body which rotates around the hip rotating motor (401), wherein the center of the guide rail is defined Is set as a reference position of the front movement module (41) with a distance from the axis of the rear trunk hip rotating motor (401) of The distance between the axis of the hip leg bending motor (402) and the plane of the frame (1) is that The thigh (403) and the shank (405) are of the length The radius of the wheel is From the geometrical relationship ; Establishing a coordinate system for the two-wheeled vehicle, wherein an inertial coordinate system fixedly connected with the ground is Wherein As the origin point of the light beam, Is an orthogonal vector in a general horizontal plane, Vertically downward, in Wherein the frame (1) is fixedly connected with Wherein Is the mass center of the frame (1) and the position thereof is Vector quantity Vector along the longitudinal axis of the frame (1) The vertical frame (1) faces downwards, and the front trunk and the rear trunk are fixedly connected respectively Wherein the origin is On the plane of the frame (1), the position is that Wherein Vector for the offset of the slide block of the front trunk relative to the center of the slide rail Vector along the axis direction of the respective hip-leg-bending motor (402) Is directed downwards along the direction of the steering shaft, and the fixed connection of the front wheel (407) and the rear wheel (407) is respectively Wherein Is fixedly connected with the center of mass of the wheel hub motor (406), coincides with the center of shape of the wheel hub motor (406) and is positioned in Vector quantity Respectively along the rotation axis direction of the front wheel (407) and the rear wheel (407), and the contact points of the front wheel and the ground are respectively The plane motion process of the double-wheel robot keeps balance, namely the inclination angle is zero, and the direction vector is In the vertical direction and And (3) with Respectively parallel with the circle centers of the front wheel and the rear wheel To the contact point Vectors of (2) are respectively , ; The course angle of the frame (1) relative to the ground system is recorded as The rotation angle of the front trunk and the rear trunk relative to the longitudinal axis of the frame (1) is The rotation angle of the front wheel and the rear wheel relative to the initial position is In the initial state, the device is in a state of being in contact with the body, ; In parallel with each other, And (3) with Respectively parallel with coordinate system The transformation relation between them is with Which represents a slave coordinate system To the point of Homogeneous transformation matrix of (a) transformation matrix The translation vectors of (a) are respectively And the rotation matrices are respectively , For the coordinate system A kind of electronic device Rotation of the shaft A rotation matrix of angles; both wheels (407) do not slip, their contact points with the road surface Two speed constraint equations exist at each point The positions of (2) are: ; ; time derivative of contact position to obtain speed , For wheels with pure rolling movement, contact points And The speed at this point should be Combining the previous coordinate system change relation to obtain a non-complete constraint equation of the two-wheel vehicle: ; ; Due to The constraint equation is equivalent to four algebraic equations, and the positive kinematic form is written as The constraint equation is equivalent to four algebraic equations, and the positive kinematic expression of the two-wheeled vehicle is obtained by solving the algebraic equation set: ; and obtaining a positive kinematic expression of the two-wheeled vehicle by solving the equation set: ; Giving a kinematic relationship between a working space and a configuration space of a two-wheeled vehicle robot, wherein the working space comprises three plane motion degrees of freedom And a degree of freedom for structural deformation While the configuration space comprises the rotational speed of the front and rear wheels (407) And front and rear handle bar corners These four independent variables; During exercise, the origin of the front trunk Is kept at the initial position I.e. And taking it and its derivative form Substituting into a positive kinematic equation to obtain: ; ; wherein the first expression represents the kinematic relationship of the planar motion working space and the configuration space, and the last expression is for maintaining The physical meaning of the servo constraint condition which is required to be artificially added is that the speed components of the front wheel and the rear wheel along the longitudinal axis direction of the frame (1) are the same.
2. The method for controlling the double-wheel robot with double-wheel driving and double-steering control according to claim 1, wherein the front movement module (41) and the rear movement module (42) are provided with a hip rotation motor (401), a hip leg bending motor (402), a knee joint motor (404) and a hub motor (406), the hip rotation motor (401) is arranged at the uppermost end of the movement module and is configured to change the direction of the movement module relative to the frame (1), the hip leg bending motor (402) is arranged below the hip rotation motor (401) and the rotating shaft is perpendicular to the rotating shaft of the hip rotation motor (401), the hip leg bending motor (402) is connected with the knee joint motor (404) through a thigh (403) connecting piece, the knee joint motor (404) is connected with the hub motor (406) through a shank (405), and the hub motor (406) is in driving connection with wheels (407).
3. The method according to claim 2, wherein the front movement module (41)/rear movement module (42) is configured to perform an extension and retraction movement by the hip leg bending motor (402) and the knee joint motor (404), and the hip rotation motor (401) and the knee joint motor (404) have the same fixed angle in movement to maintain the height of the wheel to the frame (1) and center the wheel (407) over the axis of the hip rotation motor (401).
4. The two-wheeled robot control method with two-wheeled drive and two-steering control according to claim 1, characterized in that the frame (1) is provided with a linear position sensor, both ends of which are provided on the front frame (1) and the rear frame (1), respectively, to measure the relative displacement between them, and an inertial measurement unit configured to measure the vehicle body posture.

Description

Double-wheel robot with double-wheel driving and double-steering control and control method Technical Field The invention relates to the technical field of double-wheel robots, and particularly provides a double-wheel robot with double-wheel driving and double-steering control and a control method. Background The two-wheeled vehicle has simple structure and flexible mobility, and is suitable for crowded and complex environments. Bicycles and self-balancing vehicles are two main configurations of two wheelers, and their combination allows good stability of movement of the two wheelers at both higher and lower travel speeds. Because of the inconsistent configuration space of the two classes of vehicles, configuration switching of the bicycle and balance car in a two-dimensional planar work space requires the introduction of redundant drives, which can create over-restraint and wheel slip. The main types of two-wheeled vehicles include bicycles and self-balancing vehicles. Both wheels of the bicycle are placed along the longitudinal axis of the frame, essentially a static instability system, the direction of advance of which is different from the direction of toppling. When it moves at higher speeds, lateral centrifugal forces can be generated to balance the dumping gravitational moment. Based on the characteristics, the bicycle can obtain a stable equilibrium state through the active control of the steering angle of the handlebar at high speed, and even can realize self-stabilization under the condition of no active control. However, the balance state stability of the bicycle at low speed is poor. Unlike bicycle mechanisms, the self-balancing vehicle is driven by two coaxial driving wheels, the advancing direction of which is the same as the dumping direction. Under the low-speed and near-static state, the self-balancing vehicle can maintain balance by utilizing inertial force by changing the angular acceleration of the driving wheel. However, since the vehicle body acceleration is used to maintain balance, the speed controllability of the self-balancing vehicle is limited, and it is difficult to achieve high acceleration and deceleration performance. Meanwhile, since the destabilizing direction is parallel to the traveling direction, the balance car generally does not travel at a high speed in consideration of safety after destabilization. If the two-wheel vehicle can be switched between two modes of the bicycle and the self-balancing vehicle, the advantages of the two modes can be considered, and the two-wheel vehicle has better maneuverability, flexibility and balancing capacity in a wide speed range. Switching between the two modes of the bicycle and the self-balancing vehicle requires that the two-wheeled vehicle have omnidirectional movement with three degrees of freedom in a plane. The self-balancing vehicle has no steering wheel, but two wheels are driven independently, so that two degrees of freedom of forward and autorotation can be realized. Currently, neither of these two configurations achieves planar omni-directional motion. Intuitively, when two wheels rotate to a configuration of a self-balancing vehicle, a driven wheel cannot be driven by a driving wheel, so that a singular point of driving control is generated. From the configuration space point of view, this is due to the fact that there is an essential difference in the configuration of the self-balancing vehicle and the dual-steering bicycle. Therefore, in order to realize the two-wheeled vehicle switching between the two modes of the bicycle and the self-balancing vehicle and to realize the planar three-degree-of-freedom motion, both wheels are required to be steered and driven. However, this design contains four control inputs, exceeding the number of planar degrees of freedom of movement, creating an overconstraint. The presence of over-constraints can cause slipping of the wheels, making the kinematic and dynamic models of the vehicle based on non-slip conditions ineffective, causing vibrations of the frame and making dexterous maneuvers difficult. Disclosure of Invention Based on the above, the invention provides a double-wheel robot with double-wheel driving and double-steering control and a control method thereof, so as to realize smooth switching of two configurations of a bicycle and a self-balancing vehicle, and solve the over-constraint problem caused by a redundant driver by introducing the deformation freedom degree of the double-wheel vehicle structure and the active control of the degree of freedom. In order to achieve the above object, in a first aspect, the present invention provides a dual-wheel robot with dual-wheel driving and dual-steering control, comprising a vehicle type module, a front movement module and a rear movement module, wherein the vehicle type module comprises a vehicle frame, a front trunk connecting plate and a rear trunk connecting plate, the front end of the vehicle frame is provided with a guide rai