CN-121995944-A - Wheel leg robot reconstruction stability control method considering influence of rigidity of foot wheel

CN121995944ACN 121995944 ACN121995944 ACN 121995944ACN-121995944-A

Abstract

The invention discloses a stability control method for reconstructing a wheel leg robot by considering the influence of rigidity of a foot wheel, which comprises the steps of 1, establishing a wheel leg robot coordinate system, 2, calculating and outputting ideal displacement of a quenching and tempering center sliding block motion in the reconstruction process of the wheel leg robot by inputting deviation and deviation change rate of ideal ZMP and actual ZMP into a fuzzy controller, 3, differentiating the ideal displacement of the sliding block to obtain ideal speed, inputting the ideal displacement and ideal speed in the reconstruction process into an LQG controller to obtain control voltage, then inputting the control voltage into a dynamics model of an adjusting mass center mechanism to obtain actual displacement of the quenching and tempering center sliding block in the reconstruction process, and 4, calculating the actual ZMP value of the wheel leg robot, and feeding the difference between the actual ZMP and the ideal ZMP back into the fuzzy controller to form closed loop control of stability. The invention can realize that the actual ZMP position of the robot approaches to the ideal position in the reconstruction process under the influence of the rigidity of the foot wheel, thereby improving the stability of the system during reconstruction.

Inventors

LIU JUN
WANG RONG

Assignees

合肥工业大学

Dates

Publication Date: 20260508
Application Date: 20260209

Claims (6)

1. A stability control method for a wheel leg robot reconstruction taking influence of rigidity of foot wheels into consideration comprises a vehicle body, a horizontal lifting mechanism, an adjusting mass center mechanism and a foldable leg mechanism, wherein the vehicle body consists of a front vehicle body and a rear vehicle body, the horizontal lifting mechanism, the adjusting mass center mechanism and the foldable leg mechanism are arranged on a top plate of the rear vehicle body, the horizontal lifting mechanism is in a left-right symmetrical arrangement mode, a lower rod piece of the horizontal lifting mechanism is connected with the front vehicle body, an upper rod piece and an electric push rod form a movable pair, the tail end of the upper rod piece is directly fixedly connected with a lifting motor output shaft of the rear vehicle body, the adjusting mass center mechanism consists of a transverse ball screw sliding rail, a longitudinal ball screw sliding rail, a driving motor and a sliding block carried by the sliding rail, the foldable leg mechanism is in a symmetrical design, the two leg mechanisms are identical in structure, and are respectively composed of a thigh, a shank joint, a knee joint and an ankle joint are correspondingly configured on a supporting foot with four foot wheels, and the stability control method is characterized by comprising the following steps: step one, establishing a coordinate system in the reconstruction process of the wheel leg robot; step two, establishing the displacement of the sliding block in the mass center adjusting mechanism according to the step (1) Control voltage with the driving motor An electromechanical dynamics model in between; (1) in the formula (1), the components are as follows, Representing an equivalent current constant of the adjusting centroid mechanism; Representing an equivalent torque constant of the adjustment centroid mechanism; Is the transmission ratio of the transverse ball screw and the longitudinal ball screw, and , Leads of transverse and longitudinal ball screws; And The equivalent moment of inertia and the equivalent viscous damping coefficient of the mass center adjusting mechanism are respectively; In order to adjust the acceleration of the centroid slider, To adjust the speed of the centroid slider; Step three, a reconstructed nonlinear vibration model of the wheel-leg robot is established, and the vertical elastic force of the foot wheel of the wheel-leg robot is calculated, so that an improved ZMP criterion of the wheel-leg robot after the rigidity of the foot wheel is considered is obtained; Step four, obtaining the wheel leg robot in the reconstruction process according to the improved ZMP criterion Moment of time of day of actual zero moment point ; Fifthly, taking the center of the sole support area of the wheel leg robot as an ideal zero moment point position Will be From the ideal zero moment point position Deviation of (2) Deviation rate of change Input into the fuzzy controller and output the sliding block in the mass center adjusting mechanism Ideal displacement of time of day Will be After differentiation, the slide block is obtained Ideal speed of time ; Step six, will Ideal displacement of the slider at the moment And ideal speed Is input into the LQG controller and obtained by a Kalman state observer in the LQG controller Observed value of moment slider displacement And observed value of velocity And the deviation of the two is used for calculating and adjusting the driving motor of the mass center mechanism Control voltage at time Thereby obtaining the wheel leg robot Actual zero moment point position at time ; Step seven, will Assignment to And then returning to the fourth step for sequential execution until the wheel leg robot is in reconstruction And the position approaches to an ideal position, so that the stability control of the wheel leg robot in the reconstruction process is realized.
2. The method for controlling the stability of the reconstruction of the legged robot considering the influence of the rigidity of the foot wheel according to claim 1, wherein the first step is performed as follows: Step 1.1, establishing a basic coordinate system on the horizontal plane where the supporting feet are located Will be Origin of (2) Is arranged at the middle position of the two foot bottom plates, The positive direction of the shaft is the advancing direction of the wheel leg robot, and the basic coordinate system The positive direction of the axis is vertical to the horizontal plane and faces upwards, and the basic coordinate system The positive direction of the axis being perpendicular to Shaft and method for producing the same The axis lying in the plane pointing to the outer side of the vehicle body; Step 1.2, sequentially establishing an appendage coordinate system of a left leg ankle joint, an appendage coordinate system of a left knee joint and an appendage coordinate system of a left hip joint, an appendage coordinate system of a right leg ankle joint, an appendage coordinate system of a right knee joint, an appendage coordinate system of a right hip joint and an appendage coordinate system of a horizontal lifting mechanism, and marking any one appendage coordinate system as an a-th appendage coordinate system Any one of lifting joints corresponding to the left ankle joint, the left knee joint, the left hip joint, the right ankle joint, the right knee joint, the right hip joint and the horizontal lifting mechanism is marked as an a-th joint, 。
3. The method for controlling the stability of the reconstruction of the legged robot considering the influence of the rigidity of the foot wheel according to claim 2, wherein the third step is performed as follows: Step 3.1, establishing a reconstructed nonlinear vibration model of the wheel leg robot according to the formula (2); (2) in the formula (2), the amino acid sequence of the compound, Is the total mass of the wheel leg robot, , The center of mass of the wheel leg robot in the reconstruction process is respectively Acceleration and displacement changes in the axial direction, , Respectively the actual vertical displacement and the vertical acceleration of the wheel leg robot, , Is the pitch angle and pitch angle acceleration of the wheel leg robot, Is the center of mass of the wheel leg robot Acceleration in the axial direction, g is gravitational acceleration, , Is the linear rigidity of the front and rear foot wheels, , Is the nonlinear coefficient of the front and rear foot wheels, Is the rotational inertia of the wheel leg robot relative to the center of mass, Is the distance between the centroid and the forefoot wheel axle, Is the distance between the mass center and the rear foot wheel axle; step 3.2, will And After assignment, solving the equation (2) to obtain the deformation of the forefoot wheel Deformation of the rear foot wheel ; Step 3.3, calculating the vertical elasticity of the front foot wheel according to the step (3) And vertical elasticity of rear foot wheel : (3) In the formula (3), the amino acid sequence of the compound, And Is the vertical elasticity of the front wheel and the rear wheel, And For the linear stiffness of the front and rear wheels, And Is the nonlinear coefficient of the front foot wheel and the rear foot wheel, And Is the vertical deformation of the front foot wheel and the rear foot wheel; step 3.4, establishing a ZMP criterion after the improvement of the wheel leg robot according to the formula (4): (4) In the formula (4), the amino acid sequence of the compound, Is any first one of a horizontal lifting mechanism, a sliding block for adjusting a mass center mechanism, two thighs, 2 calves and 2 support feet of a robot The mass of the individual components is such that, Is the number of components, and =8, 、 The first is the wheel leg robot Of individual members Axial sum The acceleration of the center of mass in the axial direction, 、 The first is the wheel leg robot The mass centre of each component being in the basic coordinate system Axial sum An axial coordinate; And The vertical elasticity of the front foot wheel and the vertical elasticity of the rear foot wheel are respectively.
4. A method for controlling the stability of a legged robot reconstruction taking into account the influence of the stiffness of a foot wheel according to claim 3, wherein the sixth step is performed as follows: Step 6.1, will Actual displacement of the slider at the moment And actual speed And Control voltage at time Inputting into Kalman state observer for processing to obtain Observing displacement of the slide at a moment And observation speed ; Step 6.2, the sliding block is arranged on Ideal displacement of time of day With the slide block Time of day observation displacement Deviation of (2) And Ideal speed of time And observation speed Deviation of (2) Input into LQG controller to obtain driving motor in formula (5) Control voltage at time : (5) In the formula (5), the amino acid sequence of the compound, Is an optimal feedback gain matrix; Is that Error state vector of moment of time, and ; Step 6.3, will Substituting into (2) to obtain the sliding block in the mass center adjusting mechanism Actual displacement of time of day And actual speed ; Step 6.4, will Inputting the improved ZMP criterion, and outputting the position of the wheel leg robot in Actual zero moment point position at time 。
5. An electronic device comprising a memory and a processor, wherein the memory is configured to store a program that supports the processor to perform the stability control method of any one of claims 1-4, the processor being configured to execute the program stored in the memory.
6. A computer readable storage medium having a computer program stored thereon, characterized in that the computer program when executed by a processor performs the steps of the stability hierarchy control method of any one of claims 1 to 4.

Description

Wheel leg robot reconstruction stability control method considering influence of rigidity of foot wheel Technical Field The invention belongs to the technical field of robot stability control, and particularly relates to a stability control method for a wheel leg robot reconstruction process. Background The wheel leg robot is a novel wheel leg robot which is based on the structural design of an automobile and can deform between an automobile state and a similar human state. The automobile can run at high speed on the urban flat road surface, can enter the building in a similar manner, and can directly reach the room through gait walking and stair climbing, so that point-to-point rapid and direct is realized. At present, the research direction of the wheel-leg robot mainly comprises mechanical structure and driving design, motion planning and control, environment perception and intelligent decision making, personal intelligence and the like. The reconstruction of the traditional wheel-leg robot between the wheel-type construction state and the leg-type construction state is partial reconstruction, namely, the reconstruction is not greatly different in appearance, structure and mass center position before and after the reconstruction. Many students only analyze and control the wheel-type running or leg-type running motions of the wheel-leg robot, but less researches are involved on the motion stability problem of the wheel-leg robot in the process of switching between different motion configurations. In the aspect of adjusting the stability of the robot, most of the existing researches are to adjust the mass center of the robot to achieve balance by adjusting the rotation rule of the joint motor to deform the leg mechanism, but the leg joint of the robot is also responsible for the unfolding action in the reconstruction process, which leads to the robot occupying a larger enveloping space and having larger energy consumption. In the aspect of the stability control criterion of the wheel leg robot, the stability criterion based on a zero moment point method which considers that the robot is a rigid foot is the main stream, but the traditional criterion failure is caused by the fact that the mass center of the robot changes due to the elasticity of the foot end is not considered. In the aspect of a stability control strategy of the wheel leg robot, most of the control strategies are based on information such as a robot inclination angle acquired by a sensor, and the robot is subjected to traditional feedback control or model-based predictive control, so that the robustness is poor or the calculated amount is huge. Disclosure of Invention The invention aims to solve the defects in the prior art, and provides a stability control method for the reconstruction motion of a wheel leg robot, so that the movement of a sliding block in a centroid adjusting mechanism can be judged and controlled according to the motion parameters of the wheel leg robot, and the centroid position of the wheel leg robot can be changed, thereby improving the stability of the reconstruction motion of the wheel leg robot. In order to achieve the aim of the invention, the invention adopts the following technical scheme: The invention relates to a stability control method for reconstructing a wheel leg robot considering the influence of rigidity of a foot wheel, which comprises a vehicle body, a horizontal lifting mechanism, an adjusting mass center mechanism and a foldable leg mechanism, wherein the vehicle body consists of a front vehicle body and a rear vehicle body, the horizontal lifting mechanism, the adjusting mass center mechanism and the foldable leg mechanism are arranged on a top plate of the rear vehicle body, the horizontal lifting mechanism is in a left-right symmetrical arrangement mode, a lower rod piece of the horizontal lifting mechanism is connected with the front vehicle body, an upper rod piece and an electric push rod form a mobile pair, the tail end of the upper rod piece is directly fixedly connected with a lifting motor output shaft of the rear vehicle body, the adjusting mass center mechanism consists of a transverse ball screw slide rail, a longitudinal ball screw slide rail, a driving motor and a slide block carried by the slide rail, the foldable leg mechanism adopts a symmetrical design, and the two leg mechanisms are identical in structure and are respectively formed by thighs, calves and support feet with four foot wheels, knee joints and ankle joints. Step one, establishing a coordinate system in the reconstruction process of the wheel leg robot; step two, establishing the displacement of the sliding block in the mass center adjusting mechanism according to the step (1) Control voltage with the driving motorAn electromechanical dynamics model in between; (1) in the formula (1), the components are as follows, Representing an equivalent current constant of the adjusting centroid mechanism; Representing an equivale