Gait planning method, robot and computer-readable storage medium

Patent metadata

Field	Value
Publication number	US-12304084-B2
Application number	US-202218091292-A
Country	US
Kind code	B2
Filing date	Dec 29, 2022
Priority date	Mar 2, 2022
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

A gait planning method for a robot includes: constructing a first phase variable of a gait planning of the robot, wherein the first phase variable is a function of two position components of a torso of the robot on a horizontal plane; constructing a second phase variable based on the first phase variable, wherein the second phase variable is a function of the first phase variable, and a slope of the second phase variable is smaller than a slope of the first phase variable when a foot of a swing leg of the robot starts to touch a support surface; and performing the gait planning on the foot of the swing leg using the second phase variable to obtain a planned trajectory of the foot of the swing leg.

First claim

What is claimed is:

1. A computer-implemented gait planning method for a robot, comprising:
constructing, by a processor of the robot, a first phase variable for gait planning of the robot, wherein the first phase variable is a function of two position components of a torso of the robot on a horizontal plane;
determining, by the processor, a product of the first phase variable and a preset adjustment coefficient, and obtaining a ratio between an inverse hyperbolic sine function of the product and an inverse hyperbolic sine function of the preset adjustment coefficient as a second phase variable;
performing, by the processor, the gait planning on a foot of a swing leg of the robot using the second phase variable to obtain a planned trajectory of the foot of the swing leg; and
controlling, by the processor, the robot to move according to the planned trajectory of the foot of the swing leg.

2. The method of claim 1 , wherein constructing the first phase variable of the gait planning of the robot comprises:
establishing a functional relationship between the first phase variable and the two position components of the torso of the robot on the horizontal plane using a binary quadratic equation with undetermined coefficients;
establishing a system of solution equations for each undetermined coefficient of the binary quadratic equation according to a preset value of the first phase variable at an initial moment and a preset value of the first phase variable at a termination moment;
simplifying a number of the undetermined coefficients of the binary quadratic equation according to the system of solution equations to obtain a simplified functional relationship;
constructing an optimization objective function corresponding to the simplified functional relationship; and
calculating each of the undetermined coefficients of the binary quadratic equation according to the optimization objective function and a preset optimization algorithm, so as to complete the constructing of the first phase variable.

3. The method of claim 2 , wherein establishing the functional relationship between the first phase variable and the two position components of the torso of the robot on the horizontal plane using the binary quadratic equation with undetermined coefficients, comprises:
establishing the functional relationship as follows: Φ=a 1 x w +a 2 y w +a 3 x w y w +a 4 x w 2 +a 5 y w 2 +a 6 , where x w and y w represent the two position components of the torso of the robot on the horizontal plane, a 1 , a 2 , a 3 , a 4 , a 5 and a 6 are the undetermined coefficients, and Φ is the first phase variable.

4. The method of claim 2 , wherein establishing the system of solution equations for each undetermined coefficient of the binary quadratic equation according to the preset value of the first phase variable at the initial moment and the preset value of the first phase variable at the termination moment, comprises:
establishing a first solution equation of the binary quadratic equation according to the preset value of the first phase variable at the initial moment;
establishing a second solution equation of the binary quadratic equation according to the preset value of the first phase variable at the termination moment;
substituting a preset position error relationship into the second solution equation to obtain derivative solution equations of the second solution equation, wherein the position error relationship is a relationship between two position error components of the torso of the robot on the horizontal plane; and
using the first solution equation and the derivative solution equations of the second solution equation as the system of solution equations.

5. The method of claim 2 , wherein the optimization objective function is as follows: J=Σ(Φ(t i )−t i /T) 2 , where T is a cycle of a linear inverted pendulum model of the robot, t i is an i-th moment in the cycle, Φ(t i ) is a value of the first phase variable corresponding t i , and J is the optimization objective function.

6. A robot comprising:
one or more processors; and
a memory coupled to the one or more processors, the memory storing programs that, when executed by the one or more processors, cause performance of operations comprising:
constructing a first phase variable for gait planning of the robot, wherein the first phase variable is a function of two position components of a torso of the robot on a horizontal plane;
determining a product of the first phase variable and a preset adjustment coefficient, and obtaining a ratio between an inverse hyperbolic sine function of the product and an inverse hyperbolic sine function of the preset adjustment coefficient as a second phase variable; and
performing the gait planning on a foot of a swing leg of the robot using the second phase variable to obtain a planned trajectory of the foot of the swing leg, and controlling the robot to move according to the planned trajectory of the foot of the swing leg.

7. The robot of claim 6 , wherein constructing the first phase variable of the gait planning of the robot comprises:
establishing a functional relationship between the first phase variable and the two position components of the torso of the robot on the horizontal plane using a binary quadratic equation with undetermined coefficients;
establishing a system of solution equations for each undetermined coefficient of the binary quadratic equation according to a preset value of the first phase variable at an initial moment and a preset value of the first phase variable at a termination moment;
simplifying a number of the undetermined coefficients of the binary quadratic equation according to the system of solution equations to obtain a simplified functional relationship;
constructing an optimization objective function corresponding to the simplified functional relationship; and
calculating each of the undetermined coefficients of the binary quadratic equation according to the optimization objective function and a preset optimization algorithm, so as to complete the constructing of the first phase variable.

8. The robot of claim 7 , wherein establishing the functional relationship between the first phase variable and the two position components of the torso of the robot on the horizontal plane using the binary quadratic equation with undetermined coefficients, comprises:
establishing the functional relationship as follows: Φ=a 1 x w +a 2 y w +a 3 x w y w +a 4 x w 2 +a 5 y w 2 +a 6 , where x w and y w represent the two position components of the torso of the robot on the horizontal plane, a 1 , a 2 , a 3 , a 4 , a 5 and a 6 are the undetermined coefficients, and Φ is the first phase variable.

9. The robot of claim 7 , wherein establishing the system of solution equations for each undetermined coefficient of the binary quadratic equation according to the preset value of the first phase variable at the initial moment and the preset value of the first phase variable at the termination moment, comprises:
establishing a first solution equation of the binary quadratic equation according to the preset value of the first phase variable at the initial moment;
establishing a second solution equation of the binary quadratic equation according to the preset value of the first phase variable at the termination moment;
substituting a preset position error relationship into the second solution equation to obtain derivative solution equations of the second solution equation, wherein the position error relationship is a relationship between two position error components of the torso of the robot on the horizontal plane; and
using the first solution equation and the derivative solution equations of the second solution equation as the system o

Assignees

• Ubtech Robotics Corp Ltd

Inventors

• Luo Qiuyue
• Liu Yizhang
• Ge Ligang
• Chen Chunyu
• Zhou Jiangchen
• Yan Meng

Classifications

• G05B13/04

  involving the use of models or simulators · CPC title

• B25J9/1653

  parameters identification, estimation, stiffness, accuracy, error analysis · CPC title

• B25J9/163

  learning, adaptive, model based, rule based expert control · CPC title

• B25J9/1602

  characterised by the control system, structure, architecture · CPC title

• Y02T10/40

  Engine management systems · CPC title