CN116118896A - Service robot chassis and control method thereof - Google Patents
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- B62D57/00—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track
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- B25J11/008—Manipulators for service tasks
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Abstract
The invention discloses a service robot chassis and a control method thereof, and belongs to the technical field of robots. The robot adopts a chassis structure with combined legs and feet, and comprises a main body, a first mechanical leg and foot module, a second mechanical leg and foot module and a hardware circuit module. The first mechanical leg foot module and the second mechanical leg foot module are symmetrically arranged on two sides of the main body, the bottom is provided with the moving wheels, different moving modes can be switched according to different scenes, and the combined advantages of high wheel type moving efficiency and strong foot type terrain adaptability are achieved. When the robot runs on the flat ground, the direct-drive motor drives the wheels to move; when the robot encounters a complex terrain, the motions such as single-foot standing, jumping and the like can be realized by driving the joint motor to change the gesture of the leg, so as to pass through the complex obstacle. The invention combines the advantages of the wheeled robot and the foot type robot, and effectively improves the mobility of the service robot.
Description
Technical Field
The invention belongs to the technical field of robots, and particularly relates to a service robot chassis and a control method thereof.
Background
With the progress of technology and the development of the robot field, robots are gradually applied to improve the living standard and quality of people, wherein service robots, which are a kind close to the lives of people, have been started to move into the fields of vision of people.
Mobility is the most critical ring of service robots, determining the stability, flexibility and maneuverability of the service robots. At present, the service robots mainly comprise wheeled robots, foot robots and wheels, have the advantage of high moving speed, can improve moving efficiency, but have poor adaptability and are more laborious when coping with complex terrains; the foot type robot has the super adaptability to the ground, has rich movement modes, has good flexibility and stability, can easily cope with complex ground, but has complex structure, higher development cost and lower movement efficiency. The wheel foot type can switch corresponding moving modes according to different scenes by adding wheels at the tail ends of the legs of the foot type, so that the wheel type super-strong adaptability has the advantages of high wheel type moving efficiency and super-strong adaptability.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a service robot chassis and a control method thereof. The invention combines the structure of the parallel foot robot to use the plane parallel structure of two legs, has five rotating joints, and has more compact structure and higher strength. As a robot platform, a mechanical arm can be arranged on the platform, and a tail end control joint is added to adapt to complex working conditions.
The specific technical scheme adopted by the invention is as follows:
in a first aspect, the present invention provides a service robot chassis, comprising a main body, a first mechanical leg foot module, a second mechanical leg foot module, and a hardware circuit module;
the first mechanical leg foot module and the second mechanical leg foot module are symmetrically arranged on two sides of the main body; the first mechanical leg and foot module comprises a first motor, a second motor, a first connecting piece, a second connecting piece and a first moving wheel with a fifth motor, and the second mechanical leg and foot module comprises a third motor, a fourth motor, a third connecting piece, a fourth connecting piece and a second moving wheel with a sixth motor; the first motor, the second motor, the third motor and the fourth motor are respectively positioned at the left front, the left rear, the right front and the right rear of the main body, and the output shaft is respectively and rotatably connected with a first connecting piece, a second connecting piece, a third connecting piece and a fourth connecting piece which can flex and stretch in the vertical direction to adjust the height of the main body; the lower end parts of the first connecting piece and the second connecting piece are rotationally connected with an output shaft of a fifth motor, and the lower end parts of the third connecting piece and the fourth connecting piece are rotationally connected with an output shaft of a sixth motor;
the main body is provided with a hardware circuit module, and the hardware circuit module comprises a microcontroller, a motor control board, an information acquisition module, a power supply module and a wireless debugging module; the power supply module is used for providing working voltage for the whole circuit system and the motor; the first motor, the second motor, the third motor, the fourth motor, the fifth motor and the sixth motor are all connected with a motor control board, and the motor control board is connected with the microcontroller and is communicated by using CAN; the information acquisition module adopts CAN communication to communicate with the microcontroller; the wireless debugging module uses DBUS protocol, uses USART to communicate with the microcontroller in serial port, and controls the movement of the service robot chassis through the wireless remote controller.
Preferably, the information acquisition module comprises an external information acquisition module and a self-posture acquisition module, wherein the external information acquisition module comprises a plurality of photoelectric sensors, and the self-posture acquisition module comprises an inertia measurement unit, a torque detection unit and a motor encoder.
Preferably, the first connecting piece, the second connecting piece, the third connecting piece and the fourth connecting piece are formed by fixedly connecting a glass fiber board and a carbon fiber board through CNC workpieces.
Preferably, the power supply module comprises a voltage stabilizing module and a 24V lithium battery, and the voltage stabilizing module can output a 5V direct current power supply based on the lithium battery.
Preferably, the first motor, the second motor, the third motor, the fourth motor and the hardware circuit module are all arranged on the main body.
Preferably, the microcontroller uses an ARM chip as a main controller.
In a second aspect, the present invention provides a method for controlling a chassis of a service robot according to any one of the first aspect, specifically including:
sensing the change of the surrounding external environment and the change of the self posture of the service robot through the information acquisition module; the information acquired by the information acquisition module is fused through the hardware circuit module, and the behavior parameters of the wheel and the legs are calculated and cooperatively processed to complete target motion control acquired by the wireless debugging module;
on balance control, a dynamic model based on wheels and legs is as follows:
y＝Cx+Du
wherein 
ζ represents a state variable; />
Representing the first derivative of the state variable, y representing the system output, A representing the system matrix, B representing the control matrix, C representing the output matrix, D representing the direct transfer matrix, x representing the displacement in the lateral direction, +.>
For the first order of displacement in the lateral direction, u represents the system input force, +.>
Expressed as deviation from the equilibrium position of the pendulum +.>
Balance for pendulum distanceThe first order derivative of the deviation of the position, M represents the total mass of the first moving wheel and the second moving wheel, M represents the mass of the first moving wheel and the second moving wheel which are removed in the chassis of the service robot, g is gravity acceleration, and l is the length from the moving wheel to the mass center of the two connecting rods connected with the first order derivative;
the control law is designed to be a linear combination of system states through a hardware circuit module, namely:
u＝Kξ
designing a linear quadratic regulator to calculate a state feedback gain matrix K, and defining a cost function as follows:
wherein J represents a cost function, Q represents a semi-positive definite matrix, R represents a positive definite matrix, and t represents time;
minimizing the cost function when K satisfies
k＝R -1 B T P，
Wherein P is a constant matrix and satisfies
A T P+PA+Q-PBR -1 B T P＝0
Solving a Riccati equation to obtain a state feedback gain matrix K;
in steering control, obtaining moment output according to the error of the course angular velocity obtained by resolving the course angular velocity and the gesture through a proportional-differential controller, and superposing the moment output u obtained by balance control;
in leg length control, a proportional-differential controller is used for simulating spring damping, and the left leg length and the right leg length of the robot are controlled according to a given target leg length;
on roll angle adaptation, proportional control is used to overcome the change in the roll attitude of the robot, and the resulting torque output is superimposed on the leg length control.
Preferably, the derivation process of the kinetic model is as follows:
taking the center of the connecting line of the contact points of the first moving wheel and the ground as an origin; based on the origin, the horizontal direction is backward in the positive x direction, the horizontal direction is upward in the positive z direction, and a plane rectangular coordinate system is established;
for the horizontal direction:
wherein N is the horizontal component of the reaction force of the movable wheel pair rod, F is the external force,
is the second derivative of displacement in the transverse direction, θ is the pitch angle, and b is the coefficient of friction; p is the vertical component of the reaction force of the movable wheel pair lever;
from the moment balance equation
Wherein I is the moment of inertia of the rod,
is the second derivative of the pitch angle;
combining to obtain
wherein ,
is the first order of deviation of pitch angle, +.>
Is the second derivative of the deviation of the pitch angle;
linearizing the model at equilibrium, i.e. θ=pi, with
Expressed as deviation from equilibrium position, i.e. the pendulum distance
Thus in the equilibrium position, it is possible to obtain:
substituting the above approximation into a nonlinear model and replacing/replacing with u may result in:
neglecting the lever weight and drag effects, the model can be simplified to:
the system equation is subjected to pull-type change, so that the following steps are obtained:
(M+m)X(s)s 2 -mlΦ(s)s 2 ＝U(s)
ml 2 Φ(s)s 2 -mglΦ(s)＝mlX(s)s 2
wherein X(s) is an image function of X, wherein Φ(s) is
Where U(s) is an image function of U and s is a complex frequency.
The transfer functions available to cancel X(s) and Φ(s) are:
wherein Ppend (s) is a transfer function with pitch angle as output, P cart And(s) is a transfer function with the cart position as an output. Converting it into a state space equation representation can be obtained:
y＝Cx+Du
wherein 
Compared with the prior art, the invention has the following beneficial effects:
the invention designs a novel mechanical mechanism of the service robot, greatly improves the motion capability of the service robot, provides a simplified simpler dynamic model, has better fault tolerance, and provides a robust control algorithm for the model.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic diagram of a hardware circuit module according to the present invention;
FIG. 3 is a schematic diagram of a control algorithm according to the present invention;
FIG. 4 is a schematic view of a common posture mode of the present invention;
FIG. 5 is a schematic diagram of a standing posture mode of the present invention;
FIG. 6 is a schematic diagram of a walking gesture pattern of the present invention;
FIG. 7 is a schematic diagram of a multi-machine collaboration mode of a robotic chassis;
FIG. 8 is a schematic diagram of a four-foot stretcher mode of the robot chassis;
the reference numerals in the drawings are: the device comprises a main body 1, a first motor 2, a first connecting piece 3, a second motor 4, a second connecting piece 5, a fifth motor 6, a third motor 7, a third connecting piece 8, a fourth motor 9, a fourth connecting piece 10, a sixth motor 11, a hardware circuit module 12 and an inertial measurement unit 13.
Detailed Description
The invention is further illustrated and described below with reference to the drawings and detailed description. The technical features of the embodiments of the invention can be combined correspondingly on the premise of no mutual conflict.
As shown in fig. 1, a service robot chassis provided by the present invention mainly includes a main body 1, a first mechanical leg foot module, a second mechanical leg foot module, and a hardware circuit module 12. The main body 1 is used as a trunk, and the first mechanical leg foot module and the second mechanical leg foot module are symmetrically arranged on two sides of the main body 1 and are respectively used as a left leg and a right leg. The structure and connection of the components will be described in detail.
The first mechanical leg foot module comprises a first motor 2, a second motor 4, a first connection 3, a second connection 5 and a first moving wheel with a fifth motor 6. The first motor 2 is mounted on the left front side of the main body, and its output shaft is rotatably connected to the upper end of the first connecting member 3 and constitutes the left thigh. The second motor 4 is installed at the left rear side of the main body, and its output shaft is rotatably connected with the upper end of the second connecting piece 5 and forms a left hip joint. The lower ends of the first connecting piece 3 and the second connecting piece 5 are both rotatably connected with the output shaft of the fifth motor 6 and form a left calf, and the first connecting piece 3 and the second connecting piece 5 are of a structure capable of being bent and stretched in the vertical direction to adjust the height of the main body 1. Under this kind of structure, first mechanical leg foot module wholly constitutes left leg structure.
The second mechanical leg foot module comprises a third motor 7, a fourth motor 9, a third connection 8, a fourth connection 10 and a second moving wheel with a sixth motor 11. The second motor 4 is mounted on the right front side of the main body, and its output shaft is rotatably connected to the upper end of the third connecting member 8 and constitutes the right thigh. The fourth motor 9 is mounted on the right rear side of the main body, and its output shaft is rotatably connected to the upper end of the fourth connecting member 10 and constitutes the right hip joint. The lower end parts of the third connecting piece 8 and the fourth connecting piece 10 are both rotatably connected with the output shaft of the sixth motor 11 and form a right calf, and the third connecting piece 8 and the fourth connecting piece 10 are of structures capable of being bent and stretched in the vertical direction to adjust the height of the main body 1. Under this kind of structure, second mechanical leg foot module wholly constitutes right leg structure.
Based on the above-described structure, the first motor 2, the second motor 4, the third motor 7, and the fourth motor 9 are regarded as joint motors, and the fifth motor 6 and the sixth motor 11 are regarded as hub motors according to the functionality. As shown in fig. 2, a main body 1 of the chassis of the service robot of the present invention is provided with a hardware circuit module 12, and the hardware circuit module 12 mainly includes a microcontroller, a motor control board, an information acquisition module, a power module and a wireless debugging module. Specifically, the power supply module is used for providing working voltage for the whole circuit system and the motor; the first motor 2, the second motor 4, the third motor 7, the fourth motor 9, the fifth motor 6 and the sixth motor 11 are all connected with a motor control board, and the motor control board is connected with a microcontroller and is communicated by using CAN; the information acquisition module adopts CAN communication to communicate with the microcontroller; the wireless debugging module uses DBUS protocol, uses USART to communicate with the microcontroller in serial port, and controls the movement of the service robot chassis through the wireless remote controller.
In this embodiment, the information acquisition module includes an external information acquisition module and a self-posture acquisition module, the external information acquisition module includes a plurality of photoelectric sensors, and the self-posture acquisition module includes an inertial measurement unit 13, a torque detection unit and a motor encoder. The first connecting piece 3, the second connecting piece 5, the third connecting piece 8 and the fourth connecting piece 10 are formed by fixedly connecting a glass fiber plate and a carbon fiber plate through CNC workpieces. The power supply module comprises a voltage stabilizing module and a 24V lithium battery, and the voltage stabilizing module can output a 5V direct current power supply based on the lithium battery. The first motor 2, the second motor 4, the third motor 7, the fourth motor 9 and the hardware circuit module 12 are all disposed on the main body 1. The microcontroller adopts an ARM chip as a main controller.
Based on the chassis of the service robot, the invention also designs a method for realizing the control of the service robot and improving the stability of the service robot by utilizing the hardware circuit module 12, and particularly, the hardware circuit module 12 is divided into a perception layer, a decision layer and a control layer. The sensing layer mainly senses the change of the surrounding external environment and the change of the posture of the robot, the decision layer mainly fuses the information of the torque measuring unit and the inertial measuring unit obtained by the sensing layer, calculates the behavior parameters of the wheels and the legs, cooperates the actions of the wheels and the legs, and the control layer mainly processes the output information obtained by the decision layer, calculates according to an actual model to obtain actual corresponding driving output and outputs the actual driving output to the motor.
As shown in fig. 3, the sensing layer comprises an external information acquisition module and a self-gesture acquisition module, wherein the external information acquisition module senses the external environment through a photoelectric sensor to acquire topographic information; the self-posture acquisition module is fed back through the inertia measurement unit, the torque detection unit and the motor encoder and combines self-posture information. The decision layer comprises a data processing and control algorithm, wherein the data processing is to process external information in the sensing layer and self-posture information into digital signals, obtain better data, send the better data into the control algorithm, and perform behavior calculation according to a robot dynamics model in the control algorithm to obtain a proper control algorithm, and adjust the moment of the hub motor to keep the balance of the movement of the body; and according to the target motion control obtained by the wireless debugging module, the steering and rotating speed of the robot wheel and the leg are coordinated and controlled, so that the motion requirements of forward, backward, reverse self-starting, scram, steering and the like are completed. The control layer is mainly based on data processing, and according to an actual model, the output torque of the decision layer is fused with the model to obtain the torque or current actually output to the motors, and drive signals are sent to the motors to complete control.
For the robot dynamics model, in the balancing process, the balancing control of the robot in the longitudinal direction is mainly completed, so that the robot dynamics model is simplified into planar motion. Taking the center of the connecting line of the contact points of the first moving wheel and the ground as an origin; based on the origin, the horizontal direction is backward in the positive x direction, the horizontal direction is upward in the positive z direction, and a plane rectangular coordinate system is established. And carrying out stress analysis on the simplified model according to a geometric method:
for the horizontal direction, it is possible to obtain:
wherein M represents the total mass of the first moving wheel and the second moving wheel, M represents the mass of the service robot chassis except the first moving wheel and the second moving wheel, x is the displacement in the transverse direction, N is the horizontal component of the reaction force of the rod connected with the first moving wheel or the second moving wheel, F is the external force, l is the length of the integral mass center formed by the first moving wheel or the second moving wheel to the two connected rods, θ is the pitch angle, b is the friction coefficient,
is the first order of displacement in the lateral direction,/->
Is the second derivative of displacement in the lateral direction.
For the horizontal direction, it is possible to obtain:
where P is the vertical component of the lever reaction force to which the first or second pair of moving wheels is connected.
From the moment balance equation, it can be obtained:
where I is the moment of inertia of the rod,
is the second derivative of the pitch angle.
Combining to obtain
Linearizing the model at equilibrium, i.e. θ=pi, with
Expressed as deviation from equilibrium position, i.e. the pendulum distance
Thus in the equilibrium position, it is possible to obtain:
wherein 
Is the first derivative of the deviation of the pendulum equilibrium position.
Substituting the above approximation into a nonlinear model and replacing F with u can result in:
neglecting the lever weight and drag effects, the model can be simplified to:
the system equation is subjected to pull-type change, so that the following steps are obtained:
(M+m)X(s)s 2 -mlΦ(s)s 2 ＝U(s)
ml 2 Φ(s)s 2 -mglΦ(s)＝mlx(s)s 2
wherein X(s) is an image function of X, wherein Φ(s) is
Where U(s) is an image function of U and s is a complex frequency. The transfer functions available to cancel X(s) and Φ(s) are:
wherein Ppend (s) is a transfer function with pitch angle as output, P cart (s) is a trolley positionSet as the transfer function of the output.
Converting it into a state space equation representation can be obtained:
y＝Cx+Du
wherein 
At the same time:
in balance control, based on a dynamic model of wheels and legs, a control law is designed to be a linear combination of system states through a hardware circuit module, namely:
u＝Kξ
designing a linear quadratic regulator to calculate a state feedback gain matrix K, and defining a cost function as follows:
wherein J represents a cost function, Q represents a semi-positive definite matrix, R represents a positive definite matrix, and t represents time;
minimizing the cost function when K satisfies
K＝Kξ -1 B T P，
Wherein P is a constant matrix and satisfies
A T P+PA+Q-PBR -1 B T P＝0
Solving a Riccati equation to obtain a state feedback gain matrix K;
in steering control, according to the error of the course angular velocity obtained by feedback of the inertia measurement unit and the course angular velocity obtained by calculation of the gesture, the error is subjected to proportional-differential controller to obtain moment output, and the moment output obtained by balance control is superimposed.
In leg length control, leg length is fitted by data fed back from an articulation motor encoder, and spring damping is simulated by using a proportional-differential controller (PD controller), and left and right leg lengths of the robot are controlled according to a given target leg length.
In the roll angle self-adaption, the roll angle error obtained by the roll angle and posture calculation obtained by the inertial measurement unit is controlled by proportion to overcome the change of the roll posture of the robot, and the obtained moment output is superposed on the leg length control.
As shown in fig. 4, the mode of the common posture of the robot chassis in this embodiment can enable the robot to freely move at a high speed under the condition of low center of gravity, and has a fast moving speed and strong maneuverability.
As shown in fig. 5, the standing posture mode of the robot chassis in this embodiment can perform complex motions according to the change of leg length, so as to achieve the advantage of high adaptability of the foot-type robot.
As shown in fig. 6, the walking posture mode of the robot chassis in this embodiment is that the length of the two legs can be respectively adjusted to adapt to uneven road surfaces, and meanwhile, the walking posture of animals can be simulated to walk and go up and down stairs.
As shown in fig. 7, in the multi-machine cooperation mode of the robot chassis in this embodiment, two robots can cooperate with each other to change the two-foot robot into a four-foot stretcher robot.
As shown in fig. 8, in the four-foot stretcher mode of the robot chassis in this embodiment, the four-foot stretcher robot can change the body height to pass through a complex terrain.
The above embodiment is only a preferred embodiment of the present invention, but it is not intended to limit the present invention. Various changes and modifications may be made by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present invention. Therefore, all the technical schemes obtained by adopting the equivalent substitution or equivalent transformation are within the protection scope of the invention.
Claims (8)
1. The service robot chassis is characterized by comprising a main body (1), a first mechanical leg foot module, a second mechanical leg foot module and a hardware circuit module (12);
the first mechanical leg foot module and the second mechanical leg foot module are symmetrically arranged on two sides of the main body (1); the first mechanical leg foot module comprises a first motor (2), a second motor (4), a first connecting piece (3), a second connecting piece (5) and a first moving wheel with a fifth motor (6), and the second mechanical leg foot module comprises a third motor (7), a fourth motor (9), a third connecting piece (8), a fourth connecting piece (10) and a second moving wheel with a sixth motor (11); the first motor (2), the second motor (4), the third motor (7) and the fourth motor (9) are respectively positioned at the left front, the left rear, the right front and the right rear of the main body (1), and the output shaft is respectively and rotatably connected with a first connecting piece (3), a second connecting piece (5), a third connecting piece (8) and a fourth connecting piece (10) which can flex and stretch in the vertical direction to adjust the height of the main body (1); the lower end parts of the first connecting piece (3) and the second connecting piece (5) are rotationally connected with an output shaft of a fifth motor (6), and the lower end parts of the third connecting piece (8) and the fourth connecting piece (10) are rotationally connected with an output shaft of a sixth motor (11);
the main body (1) is provided with a hardware circuit module (12), and the hardware circuit module (12) comprises a microcontroller, a motor control board, an information acquisition module, a power module and a wireless debugging module; the power supply module is used for providing working voltage for the whole circuit system and the motor; the first motor (2), the second motor (4), the third motor (7), the fourth motor (9), the fifth motor (6) and the sixth motor (11) are all connected with a motor control board, and the motor control board is connected with the microcontroller and is communicated by using CAN; the information acquisition module adopts CAN communication to communicate with the microcontroller; the wireless debugging module uses DBUS protocol, uses USART to communicate with the microcontroller in serial port, and controls the movement of the service robot chassis through the wireless remote controller.
2. The service robot chassis according to claim 1, wherein the information acquisition module comprises an external information acquisition module and a self-posture acquisition module, the external information acquisition module comprises a plurality of photoelectric sensors, and the self-posture acquisition module comprises an inertial measurement unit (13), a torque detection unit and a motor encoder.
3. The service robot chassis according to claim 1, wherein the first connecting piece (3), the second connecting piece (5), the third connecting piece (8) and the fourth connecting piece (10) are formed by fixedly connecting a glass fiber board and a carbon fiber board through CNC workpieces.
4. The service robot chassis of claim 1, wherein the power module comprises a voltage regulator module and a 24V lithium battery, the voltage regulator module being capable of outputting a 5V dc power source based on the lithium battery.
5. A service robot chassis according to claim 1, characterized in that the first motor (2), the second motor (4), the third motor (7), the fourth motor (9) and the hardware circuit module (12) are all placed on the main body (1).
6. The service robot chassis of claim 1, wherein the microcontroller employs an ARM chip as a master controller.
7. A method of controlling a service robot chassis according to any one of claims 1 to 6, comprising the steps of:
sensing the change of the surrounding external environment and the change of the self posture of the service robot through the information acquisition module; the information acquired by the information acquisition module is fused through the hardware circuit module (12), and the behavior parameters of the wheel and the legs are calculated and cooperatively processed to complete target motion control acquired by the wireless debugging module;
on balance control, a dynamic model based on wheels and legs is as follows:
y＝Cx+Du
wherein 
ζ represents a state variable; />
Representing the first derivative of the state variable, y representing the system output, A representing the system matrix, B representing the control matrix, C representing the output matrix, D representing the direct transfer matrix, x representing the displacement in the lateral direction, +.>
For the first derivative of the displacement in the lateral direction u represents the system input,/i>
Expressed as deviation from the equilibrium position of the pendulum +.>
For first order guiding of deviation of the swing distance from the balance position, M represents total mass of the first moving wheel and the second moving wheel, M represents mass of the first moving wheel and the second moving wheel which are divided in the chassis of the service robot, g is gravitational acceleration, and l is length from the moving wheel to mass centers of two connecting rods connected with the first moving wheel and the second moving wheel;
the control law is designed to be a linear combination of system states through a hardware circuit module (12), namely:
u＝Kξ
designing a linear quadratic regulator to calculate a state feedback gain matrix K, and defining a cost function as follows:
wherein J represents a cost function, Q represents a semi-positive definite matrix, R represents a positive definite matrix, and t represents time;
minimizing the cost function when K satisfies
K＝R -1 B T P，
Wherein P is a constant matrix and satisfies
A T P+PA+Q-PBR -1 B T P＝0
Solving a Riccati equation to obtain a state feedback gain matrix K;
in steering control, obtaining moment output according to the error of the course angular velocity obtained by resolving the course angular velocity and the gesture through a proportional-differential controller, and superposing the moment output obtained by balancing control;
in leg length control, a proportional-differential controller is used for simulating spring damping, and the left leg length and the right leg length of the robot are controlled according to a given target leg length;
on roll angle adaptation, proportional control is used to overcome the change in the roll attitude of the robot, and the resulting torque output is superimposed on the leg length control.
8. The method for controlling a chassis of a service robot according to claim 7, wherein the dynamic model is derived as follows:
taking the center of the connecting line of the contact points of the first moving wheel and the ground as an origin; based on the origin, the horizontal direction is backward in the positive x direction, the horizontal direction is upward in the positive z direction, and a plane rectangular coordinate system is established;
for the horizontal direction:
wherein N is the horizontal component of the reaction force of the movable wheel pair rod, F is the external force,
is the second derivative of displacement in the transverse direction, θ is the pitch angle, and b is the coefficient of friction; p is the vertical component of the reaction force of the movable wheel pair lever; />
From the moment balance equation
Wherein I is the moment of inertia of the rod,
is the second derivative of the pitch angle;
combining to obtain
wherein ,
is the first order of deviation of pitch angle, +.>
Is pitchSecond derivative of the deviation of the angle;
linearizing the model at equilibrium, i.e. θ=pi, with
Expressed as deviation from equilibrium position, i.e. the pendulum distance
Thus in the equilibrium position, it is possible to obtain:
substituting the above approximation into a nonlinear model and replacing F with u can result in:
neglecting the lever weight and drag effects, the model can be simplified to:
the system equation is subjected to pull-type change, so that the following steps are obtained:
(M+m)X(s)s 2 -lΦ(s)s 2 ＝(s)
ml 2 Φ(s)s 2 -glΦ(s)＝lX(s)s 2
wherein X(s) is an image function of X, wherein Φ(s) is
Where U(s) is the image function of U and s is the complex frequency;
the transfer functions available to cancel X(s) and Φ(s) are:
wherein Ppend (s) is a transfer function with pitch angle as output, P cart (s) is a transfer function with the cart position as output;
converting it into a state space equation representation can be obtained:
y＝Cx+Du
wherein 
/>
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