Mobile manipulation control method and system of quadruped robot with operation arm

Patent metadata

Field	Value
Publication number	US-11813752-B2
Application number	US-202318329674-A
Country	US
Kind code	B2
Filing date	Jun 6, 2023
Priority date	Jun 7, 2022
Publication date	Nov 14, 2023
Grant date	Nov 14, 2023

Abstract

A mobile manipulation control method of a quadruped robot with an operation arm, including: obtaining current pose information of the legged mobile manipulator; decomposing a task into subtasks, and prioritizing the subtasks; based on the pose information and a dynamic model, generating a motion trajectory under each subtask; based on the dynamic model, optimizing an optimal plantar force of a supporting leg and an end-of-arm force under each subtask; based on a multi-task spatial projection method, calculating desired control quantity of all joints under different subtasks; and (d) optimizing the optimal plantar force and the desired control quantity with the whole-body dynamic model as a constraint to obtain control torques; and based on the control torques, controlling the legged mobile manipulator's motion. A control system is further provided.

First claim

What is claimed is:

1. A mobile manipulation control method of a legged mobile manipulator, comprising:
(a) obtaining current pose information of the legged mobile manipulator;
(b) decomposing a task received by the legged mobile manipulator into a plurality of subtasks, and prioritizing the plurality of subtasks; and based on the current pose information and a dynamic model, generating a whole-body motion trajectory of the legged mobile manipulator for each of the plurality of subtasks; wherein the dynamic model combines a whole-body dynamic model based on all degrees of freedom of the legged mobile manipulator and a simplified centroid dynamic model; and an arm compensation term is introduced into the simplified centroid dynamic model;
(c) based on the dynamic model, finding an optimal plantar force of a supporting leg and an optimal end-of-arm force under each of the plurality of subtasks; and based on a multi-task space projection method, calculating a desired control amount of each of joints of the legged mobile manipulator under the plurality of subtasks; and
(d) with the whole-body dynamic model as a constraint, optimizing the optimal plantar force and the desired control amount to obtain control torques of the joints of the legged mobile manipulator, wherein the joints of the legged mobile manipulator comprise an arm joint; and based on the control torques, controlling motion of the legged mobile manipulator;
wherein the simplified centroid dynamic model is expressed as follows:

m
⁡
(

p
¨

c
⁢
o
⁢
m

d

+
g

)

+

f

c
,
arm

=

∑

i
=
1

c

f
i

+

f

e
,
arm

⁢
I
⁢

ω
˙

b
d

+

n

c
,
arm

=

∑

i
=
1

c

r
i
*

×

f
i

+

n

e
,
arm

wherein m is body's gravity of the legged mobile manipulator; {umlaut over (p)} com d is a linear acceleration at a center of mass of a body of the legged mobile manipulator; {dot over (w)} b d is an angular acceleration; f i is a contact force between the supporting leg and ground; f e,arm is an interaction force between an arm end and a manipulation object; r i * is a vector from a contact point between the supporting leg and the ground to the center of mass of the body; the arm compensation term comprises an equivalent force f c,arm and an equivalent torque n c,arm ; and I is an inertia tensor of the body of the legged mobile manipulator.

2. The mobile manipulation control method of claim 1 , wherein the step of “based on the dynamic model, finding an optimal plantar force of a supporting leg and an optimal end-of-arm force under each of the plurality of subtasks” comprises:
based on an angle and mass of the arm joint, a joint reference coordinate system, a joint inertial parameter, and a mass of the legged mobile manipulator at a current moment, calculating an actual center-of-gravity position of the legged mobile manipulator in a current state; and
according to the actual center-of-gravity position, updating a force arm at the contact point between the supporting leg and ground in the current state; and based on the dynamic model, obtaining the optimal plantar force of the supporting leg and the optimal end-of-arm force by constructing a Quadratic Programming problem.

3. The mobile manipulation control method of claim 1 , wherein the step of “based on a multi-task space projection method, calculating a desired control amount of each of joints of the legged mobile manipulator under the plurality of subtasks” comprises:
mapping a speed value on the whole-body motion trajectory under each of the plurality of subtasks into a joint space based on a manipulation space projection method, and mapping a lower-priority subtask into a null space of a higher-priority subtask, thereby obtaining a desired position, velocity, and acceleration of the joints of the legged mobile manipulator.

4. The mobile manipulation control method of claim 1 , wherein an optimization problem constructed in the step of “with the whole-body dynamic model as a constraint, optimizing the optimal plantar force and the desired control amount to obtain control torques of the joints of the legged mobile manipulator” is expressed as follows:
δ*=arg min δ f T W f δ f +δ a T W a δ a ;

wherein the optimization problem is required to meet the following constraints:

S
f

(

M
⁡
(
q
)

⁢

q
¨

+

h
⁡
(

q
,

q

Assignees

• Univ Shandong

Inventors

• Rong Xuewen
• Xie Aizhen
• Chen Teng
• Zhang guoteng
• Li Yibin
• Lu Guanglin
• Bi Jian
• Fan Yong

Classifications

• B25J9/1664 Primary

  characterised by motion, path, trajectory planning · CPC title

• B25J9/162 Primary

  Mobile manipulator, movable base with manipulator arm mounted on it · 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

• G05B13/042

  in which a parameter or coefficient is automatically adjusted to optimise the performance · CPC title

• G05B2219/40298

  Manipulator on vehicle, wheels, mobile · CPC title