presenting a railbound forging manipulator
TRANSCRIPT
-
8/10/2019 Presenting a Railbound Forging Manipulator
1/6
Presenting a Railbound Forging Manipulator
PETRESCU Florian Ion1, a *,PETRESCU Relly Victoria
2,b
1Polytechnic University of Bucharest, Theory of Mechanisms and Robots department, Bucharest,
RO
2Polytechnic University of Bucharest, Transport, Traffic and Logistics department, Bucharest, RO
* The corresponding author
Keywords:Railbound forging manipulator, heavy load, control, reliability, manipulate objects to beforged, moving on a railway, precision, stability, geometry, structure, cinematic, forces.
Abstract.Heavy payload forging manipulators are mainly characterized by large load output and
large capacitive load input. The relationships between outputs and inputs have greatly influence
about the control and the reliability. Forging manipulators have become more prevalent in theindustry today. They are used to manipulate objects to be forged. The most common forging
manipulators are moving on a railway to have a greater precision and stability. They have been
called the railbound forging manipulators. In this paper one presents the general aspects of a
railbound forging manipulator, like geometry, structure, general kinematics and forces of the main
mechanism from such manipulator. Kinematic scheme shows a typical forging manipulator, with
the basic motions in operation process: walking, motion of the tong and buffering. The lifting
mechanism consists of several parts including linkages, hydraulic drives and motion pairs. An idea
of establishing the incidence relationship between output characteristics and actuator inputs is
proposed.
Introduction
A railbound forging manipulator is presented in the fig. 1.
Fig. 1.Photo of a railbound forging manipulator
-
8/10/2019 Presenting a Railbound Forging Manipulator
2/6
Presenting a Railbound Forging Manipulator
The kinematic chain plan (the kinematic diagram) of the main mechanism, which fall within a
single plane or in one or more of the other plane parallel to each other, is presented in the fig. 2 [1-
5].
Fig. 2.Cinematic schema of a forging manipulator main mechanism
Nomenclature
c1 - lifting hydraulic cylinder; c2 -the buffer hydraulic cylinder;
c3 -leaning hydraulic cylinder; l1, l2, l3variable lengths;
A-L linkages; A, B, K, F fixed linkages; 1, 3, 6, 8, 10 - variable angles; a-g constant
lengths; xB, yB, xA, yA, xK, yK, xF, yF
constant coordinates; , , 4
constant angles; - an anglewhich must be maintained constant (=-) to keep permanently the segment GM horizontally.
Fm1, Fm2, Fm3the driving forces of the mechanism.
Mechanism structure
Then can be determined easily and the structural schema (see the fig. 3).
Fig. 3.Structural schema of a forging manipulator main mechanism
-
8/10/2019 Presenting a Railbound Forging Manipulator
3/6
Applied Mechanics and Materials Vol.
The structural formula can be determined from the structural diagram (relationship 1).
)11,10,6(1)9,8,5(1)4,3(0)7,2,1(1)0( DMDMDMDMEF (1)
It is obtained: three motor dyads, one classic dyad, and a fundamental item 0 [1-5].
The mobility of the mechanism is determined with the formula (2).
33033015211323 453 CCmM (2)
It follows three degrees of freedom corresponding to the three actuators (motors) linear.
The wiring diagram can be determined now using the structural formula (see the fig. 4).
Fig. 4.Wiring diagram of a forging manipulator main mechanism
Mechanism kinematics
Permanently one knows the constant lengths (a-g) and the coordinates (xB, yB, xA, yA, xK, yK, xF,
yF), and the angle who must to be maintained constant [1-5].
In direct kinematics one knows l1, l2and must be determined: intermediary (with systems I, II,
III) l3, 1, 3, 6, 8, 10and finaly (with system IV) xM, yM[1-5].
In inverse kinematics one knows xM, yMand must be determined 1, 3, 6, 8, 10, l1, l2, l3with
systems I, II, III, IV.
It takes four independent vector contours (KLFK, KIGEDB, AHIK, AHGM) and one can write
the below systems (I, II, III, IV) [1-5].
813
813
sin)sin()(
cos)cos()(
lgyy
lgxx
FK
FK (I)
36102
36102
sinsinsin)(
coscoscos)(
ealyy
ealxx
KA
KA (III)
613
613
sin2sinsin
cos2coscos
alby
albx
K
K (II)
6103
6103
sin)sin(sin)(
cos)cos(cos)(
aflyy
aflxx
MA
MA (IV)
Inverse kinematics relationships computing
Then can be determined easily the parameters 1, 3, 6, 8, 10, l1, l2, l3solving the four systemsI, II, III, IV. Following relationships are obtained (systems 3 and 4) [1-5].
-
8/10/2019 Presenting a Railbound Forging Manipulator
4/6
Presenting a Railbound Forging Manipulator
)arccos(cos)(sin)sin(sin
sin
)cos(coscos
)arccos(cos)(sinsinsin2
sin
coscos2cos
];sin)sin(cos)cos[(4)sin()cos(4
);arccos(coscos
101010
3
610
3
610
111
3
61
3
61
03
66
222
0
22
442662
3
2
2
2
1
2
3
2
2321
6
sign
l
yyfa
l
xxfa
sign
l
bya
l
bxa
Al
bybxabybxaA
eAAlAA
AAAAAA
AM
AM
K
K
KKKK
(3)
)sin(sin)cos(cos
)]sin([2)sin(4
)]cos([2)cos(4)]sin([)]cos([)sin()cos(3
)arccos(cos)(sin)sin(
sin
)cos(cos
)]sin([)]cos([
)arccos(cos)(sinsinsin
sin
coscoscos
6106104
3
2
22222
1
888
1
38
1
38
2
3
2
31
333
61023
61023
KAKA
AMK
AMK
AMAMKK
FK
FK
FKFK
KA
KA
yyaxxaA
fyyabyaA
fxxabxaAfyyfxxbybxaA
sign
l
gyy
l
gxx
gyygxxl
sign
e
alyye
alxx
(4)
Determining driving forces of the main mechanism
RELATIONSHIPS COMPUTING
In step 1 (starting from system 5) it calculated the all external forces from the mechanism (The
inertia forces, gravitational forces and the force of the weight of the cast part).
1010
11,1011,10
11,10
88
8989
89
7
77
7
35
55
5
44
44
4
66
66
66
33
33
3
11
1212
12
11,10
1010
1010
8
88
88
7
77
77
5
55
55
4
44
44
6
66
3
33
33
1
11
11
0
G
i
G
iy
G
G
ix
G
G
i
G
iy
G
G
ix
G
M
i
M
M
iy
M
M
ix
G
i
G
iy
G
G
ix
G
G
i
G
iy
G
G
ix
G
G
i
G
iy
G
G
ix
G
H
i
H
iy
G
HGixG
G
i
G
iy
G
GixG
G
i
G
iy
G
GixG
JM
gmymF
xmF
JM
gmymF
xmF
JM
gMyMF
xMF
JM
gmymF
xmF
JM
gmymF
xmF
JM
gmymF
xmF
JM
gmymF
xmxmF
JM
gmymF
xmF
JM
gmymF
xmF
M
(5)
Is then calculated all the forces from couplers. In the end we can determine and (three) driving
forces [1-5]. In figure 5 can be monitored engine element c1 composed of kinematic elements 8-9.
-
8/10/2019 Presenting a Railbound Forging Manipulator
5/6
Applied Mechanics and Materials Vol.
Determine motive power Fm1with relations of the system 6; being two relations of calculation may
be carried out a check.
8
8
)8(
8
8
)8(
sin0sin0
cos0cos0
8
181
8
181
y
L
iy
G
m
y
L
iy
Gmy
x
L
ix
G
m
x
L
ix
Gmx
RF
FRFFF
RFFRFFF
(6)
Fig. 5.Kinematics schema of the motor mechanism c1
In figure 6 can be monitored engine element c2 composed of kinematic elements 10-11, and
determine motive power Fm2with relations of the system 7 [1-5].
Fig. 6.Kinematics schema of the motor mechanism c2
10
10
)10(
10
10
)10(
sin0sin0
cos
0cos0
10
2102
10
2102
y
H
iy
G
m
y
H
iy
Gmy
x
H
ix
G
m
x
H
ix
Gmx
RFFRFFF
RFFRFFF
(7)
-
8/10/2019 Presenting a Railbound Forging Manipulator
6/6
Presenting a Railbound Forging Manipulator
In figure 7 can be monitored engine element c3 composed of kinematic elements 1-2, and
determine motive power Fm3with relations of the system 8 [1-5].
Fig. 7.Kinematics schema of the motor mechanism c2
1
1
)1(
1
1
)1(
sin0sin0
cos
0cos0
1
313
1
313
y
E
iy
G
m
y
E
iy
Gmy
x
E
ix
G
m
x
E
ix
Gmx
RFFRFFF
RFFRFFF
(8)
Conclusions
Forging manipulators themselves have become more prevalent in the industry today.
An idea of establishing the incidence relationship between output characteristics and actuator
inputs is proposed (see the relations from systems 3 and 4).The main problems are solving positions, speeds and motor forces of the main mechanism. In
the end we can determine and (three) driving forces (the relations from systems 6-8).
References
[1]F. Gao, W. Z. Guo, Q. Y. Song, F. S. Du, Current Development of Heavy-duty Manufacturing
Equipment, Journal of Mechanical Engineering, Vol. 46, No. 19, 2010, p. 92-107.
[2]H. Ge, F. Gao, Type Design for Heavy-payload Forging Manipulators, Chinese Journal of
Mechanical Engineering, Vol. 25, No. 2, 2012, p. 197-205.
[3]G. Li, D.S. Liu, Dynamic Behavior of the Forging Manipulator under Large Amplitude
Compliance Motion, Journal of Mechanical Engineering, Vol. 46, No. 11, 2010, p. 21-28.
[4]C. Yan, F. Gao, W. Guo, Coordinated kinematic modeling for motion planning of heavy-duty
manipulators in an integrated open-die forging center, Journal of Engineering Manufacture,
Vol. 223, No. 10, 2009, p. 1299-1313.
[5]K. Zhao, H. Wang, G. L. Chen, Z. Q. Lin, Y. B. He, Compliance Process Analysis for Forging
Manipulator, Journal of Mechanical Engineering, Vol. 46, No. 4, 2010, p. 27-34.