Acceleration control method for load on powered backpack based on disturbance observer

Patent metadata

Field	Value
Publication number	US-11740611-B2
Application number	US-202016903363-A
Country	US
Kind code	B2
Filing date	Jun 16, 2020
Priority date	Apr 26, 2020
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

The disclosure belongs to the technical field of powered drive devices, and discloses an acceleration control method for a load on a powered backpack based on a disturbance observer. The method includes: S1 setting the desired acceleration of the load on the powered backpack, presetting the initial motor drive current that regulates the movement of the load according to the desired acceleration, measuring the actual acceleration of the load; S2 establishing the disturbance observer for controlling acceleration the load on the powered backpack, using the disturbance observer to calculate the motor drive current that makes the actual acceleration of the load equal to the desired acceleration, so as to realize the acceleration control of the load on the powered backpack.

First claim

What is claimed is:

1. An acceleration control method for a load on a powered backpack based on a disturbance observer, comprising the following steps:
S1 setting a desired acceleration of the load on the powered backpack, presetting an initial motor drive current according to the desired acceleration, and the load begins to move under driving of the initial motor drive current, and measuring the actual acceleration of the load;
S2 establishing the disturbance observer for acceleration control of the load on the powered backpack, and utilizing the disturbance observer to calculate a motor drive current that makes an actual acceleration of the load to be equal to the desired acceleration, thereby achieving acceleration control of the load on the powered backpack, wherein the disturbance observer is operated according to the following calculation formula:
i o =i cmd −i D +i f

wherein i o is the motor drive current, i cmd is a command drive current, that is, the sum of command currents generated by feedback control and feedforward control, i D is a corresponding drive current overcoming the disturbance, and i f is a friction compensation current, that is, a drive current required to eliminate the influence of a friction force.

2. The acceleration control method for the load on the powered backpack based on the disturbance observer according to claim 1 , wherein in step S2, the disturbance observer calculates the corresponding drive current i D overcoming the disturbance for solution according to the following calculation formula:
i D =ĩ−i cmd
wherein ĩ is a theoretical value of the command drive current required for the actual acceleration of the load.

3. The acceleration control method for the load on the powered backpack based on the disturbance observer according to claim 1 , wherein in step S2, the ĩ obtains the solution according to the following calculation formula:
ĩ= −1 [G −1 ( s ) F ( s ) X sl ( s ) s 2 ]
wherein X sl (s)s 2 = [{umlaut over (x)} sl ], {umlaut over (x)} sl is the actual acceleration of the measured load, is Laplace transform, −1 is inverse Laplace transform, s is a complex frequency, G −1 (s) is an inverse of a second-order linear model of the powered backpack, and F(s) is a low-pass filter.

4. The acceleration control method for the load on the powered backpack based on the disturbance observer according to claim 1 , wherein in step S2, the i cmd obtains solution according to the following calculation formula:

i

c
⁢
m
⁢
d

=

i
ff

+

i
PID

⁢

i
ff

=

k
ff

⁢

ℒ

-
1

[

G

-
1

(
s
)

⁢

F
⁡
(
s
)

⁢

X
r

(
s
)

⁢

s
2

]

⁢

i
PID

=

k
p

⁢
e
⁢
r
⁢
r

+

k
i

⁢

∫

err
⁢

dt

+

k
d

⁢

derr

d
⁢
t

wherein i ff is a command current of a feedforward term, k ff is an adjustable feedforward coefficient, X r (s)s 2 = [{umlaut over (x)} r ], the feedforward term is obtained from the calculation of the desired acceleration, i PID is a command current of a PID feedback term, and a load acceleration tracking deviation is err={umlaut over (x)} r −{umlaut over (x)} sl .

5. The acceleration control method for the load on the powered backpack based on the disturbance observer according to claim 1 , wherein in step S2, a friction force model comprises viscous friction and Coulomb friction, and a friction compensation current i f is calculated according to the following formula:

i
f

=

k
v

⁢

x
.

l

+

k
c

⁢

sgn
⁡
(

x
.

l

)

k
bs

wherein k v

Assignees

• Univ Huazhong Science Tech

Inventors

• Xiong cai-hua
• Zhang Qin-Hao
• He Lei
• Liu Chuang
• Chen Wen-Bin

Classifications

• G05B19/416 Primary

  characterised by control of velocity, acceleration or deceleration (G05B19/19 takes precedence) · CPC title

• A45F3/04

  Sacks or packs carried on the body by means of two straps passing over the two shoulders · CPC title

• G05B13/042 Primary

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

• G05B2219/43019

  Compensate acceleration for sudden change in load, shockless · CPC title

• A45F3/00 Primary

  Travelling or camp articles (travelling rugs A47G9/06); Sacks or packs carried on the body (convertible into other articles A45F4/00) · CPC title