Method and device for controlling gait of biped robot

Patent metadata

Field	Value
Publication number	US-10031524-B2
Application number	US-201615537117-A
Country	US
Kind code	B2
Filing date	Sep 5, 2016
Priority date	Dec 2, 2015
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A method and a device for controlling a gait of a biped robot. The method includes: selecting gait controlling parameters, and acquiring a movement trajectory of a center of mass when a zero moment point of the biped robot is located within a steady area; obtaining first numerical values of each of the gait controlling parameters of the center of mass and second numerical values of the center of mass; setting a first constraint condition when the step starting phase ends by using the first numerical values, and setting a second constraint condition when the step ending phase starts by using the second numerical values; calculating the movement trajectories of the center of mass in the step starting phase and the step ending phase on the basis of the first constraint condition and the second constraint condition, respectively; and controlling a walking of the biped robot.

First claim

What is claimed is:

1. A method for controlling a gait of a biped robot, the method comprising:
selecting gait controlling parameters of the biped robot in a step starting phase, a mid-step phase and a step ending phase, and acquiring a movement trajectory of a center of mass of the biped robot in the mid-step phase when a zero moment point of the biped robot is located within a steady area;
obtaining, according to the movement trajectory of the center of mass in the mid-step phase, first numerical values of each of the gait controlling parameters of the center of mass when the mid-step phase starts and second numerical values of each of the gait controlling parameters of the center of mass when the mid-step phase ends;
setting a first constraint condition that the center of mass is required to satisfy when the step starting phase ends by using the first numerical values, and setting a second constraint condition that the center of mass is required to satisfy when the step ending phase starts by using the second numerical values;
calculating the movement trajectories of the center of mass in the step starting phase and the step ending phase on the basis of the first constraint condition and the second constraint condition, respectively; and
controlling walking of the biped robot, so that when the biped robot is walking, the movement trajectory of the center of mass satisfies each of the movement trajectories of the center of mass in the step starting phase, the mid-step phase and the step ending phase, to realize a steady walking of the biped robot.

2. The method according to claim 1 , wherein in the controlling of the walking of the biped robot, control is performed so that when the biped robot is walking, the movement trajectory of the center of mass satisfies each of the movement trajectories of the center of mass in the step starting phase, the mid-step phase and the step ending phase, and the controlling comprises:
calculating, according to the movement trajectories of the center of mass in each of the phases, the movement trajectories of hip joints of the biped robot in the step starting phase, the mid-step phase and the step ending phase;
calculating, according to an expected movement height of ankle joints of the biped robot, the movement trajectories of the ankle joints of the two legs in the step starting phase, the mid-step phase and the step ending phase;
by using the movement trajectories of the hip joints and the ankle joints in each of the phases, the structural position relations of the legs of the biped robot and a leg length numerical value, obtaining expected angular trajectories corresponding to the hip joints, the ankle joints and knee joints in each of the phases by calculating;
selecting one or more of the hip joints, the ankle joints and the knee joints as a controlling point(s); and
when the biped robot is walking, detecting in real time a turning angle of the controlling point, and performing self-adaptive tracking controlling on the detected turning angle of the controlling point by using the expected angular trajectories of the controlling point in each of the phases, so that when the biped robot is walking, the movement trajectory of the center of mass satisfies each of the movement trajectories of the center of mass in the step starting phase, the mid-step phase and the step ending phase.

3. The method according to claim 1 , wherein each parameter of the gait controlling parameters comprises three direction components of a forward direction, a lateral direction and a vertical direction when the biped robot is walking; and
wherein, the gait controlling parameters comprise position and speed, or the gait controlling parameters comprise position, speed and acceleration.

4. The method according to claim 3 , further comprises:
according to an initial speed of the center of mass when the mid-step phase starts that is expected to reach and a conversion relation between kinetic energy and potential energy, calculating a height Hz of the center of mass in the vertical direction of the biped robot when the step starting phase ends;
wherein the acquired movement trajectory of the center of mass of the biped robot in the mid-step phase satisfies the following condition: the heights of the center of mass in the vertical direction when the mid-step phase starts and when the mid-step phase ends are both Hz.

5. The method according to claim 4 , wherein the according to an initial speed of the center of mass when the mid-step phase starts that is expected to reach and a conversion relation between kinetic energy and potential energy, calculating a height Hz of the center of mass in the vertical direction of the biped robot when the step starting phase ends comprises:
calculating a distance Δz by which the center of mass has dropped when the step starting phase ends by the following formula:
mgΔz= ½ m ( v 1 2 −v 0 2 );

wherein, v 1 is the initial speed of the center of mass when the mid-step phase starts that is expected to reach, v 0 is the speed at an initial time moment in the step starting phase, m is a mass of the biped robot, and g is gravitational acceleration; and
obtaining the height Hz of the center of mass in the vertical direction when the step starting phase ends from the difference value between the initial height of the center of mass in the vertical direction and the Δz.

6. The method according to claim 4 , wherein:
when the gait controlling parameters are position and speed, the position parameter and the speed parameter both comprise three direction components of a forward direction, a lateral direction and a vertical direction when the biped robot is walking;
the first constraint condition that the center of mass satisfies when the step starting phase ends comprises: a first forward direction constraint condition, a first lateral direction constraint condition and a first vertical direction constraint condition;
the first forward direction constraint condition comprises: when the step starting phase starts, the value of the position parameter and the value of the speed parameter are both equal to 0; and when the step starting phase ends, the value of the position parameter is equal to a first position parameter forward direction numerical value, and the value of the speed parameter is equal to a first speed parameter forward direction numerical value;
the first lateral direction constraint condition comprises: when the step starting phase starts, the value of the position parameter is equal to a half of a distance between the two feet of the biped robot, and the value of the speed parameter is equal to 0; and when the step starting phase ends, the value of the position parameter is equal to a first position parameter lateral direction numerical value, and the value of the speed parameter is equal to a first speed parameter lateral direction numerical value;
the first vertical direction constraint condition comprises: when the step starting phase starts, the value of the position parameter is equal to the initial height of the center of mass of the biped robot, and the value of the speed parameter is equal to 0; and when the step starting phase ends, the value of the position parameter is equal to the height Hz of the center of mass in the vertical direction when the step starting phase ends, and the value of the speed parameter is equal to 0;
the second constraint condition comprises: a second forward direction constraint condition, a second lateral direction constraint condition and a second vertical direction constraint condition;
the second forward direction constraint condition comprises: when the step ending phase starts, the value of the position parameter is equal to a second position parameter forward direction numerical val

Assignees

• Goertek Inc

Inventors

• Su Pengcheng

Classifications

• B25J5/00

  Manipulators mounted on wheels or on carriages (B25J1/00 takes precedence; programme-controlled manipulators B25J9/00 {; vehicle aspects B60, B62, e.g. remote-controlled steering for motor vehicles B62D1/24; control of position of vehicles G05D1/00}) · CPC title

• B62D57/032 Primary

  with alternately or sequentially lifted supporting base and legs; with alternately or sequentially lifted feet or skid (B62D57/024 takes precedence) · CPC title

• B25J9/1602

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

• G05B2219/39208

  Robot is active, realizes planned trajectory by itself · CPC title

• B25J9/1664 Primary

  characterised by motion, path, trajectory planning · CPC title