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MBDynモデル集

## 11. 減速ギア

### 入力ファイル

```# reduction_gear.mbd

#-----------------------------------------------------------------------------
# [Data Block]

begin: data;
problem: initial value;
end: data;

#-----------------------------------------------------------------------------
# [<Problem> Block]

begin: initial value;
initial time:   0.;
final time:     5.;
time step:      1.e-4;
max iterations: 10;
tolerance:      1.e-7;
end: initial value;

#-----------------------------------------------------------------------------
# [Control Data Block]

begin: control data;
output frequency: 100;
structural nodes: 2;
rigid bodies:     2;
joints:           3;
forces:           3;
end: control data;

#-----------------------------------------------------------------------------
# Design Variables
set: real M_Gear1 = 0.1; #[kg] Mass of Gear1
set: real M_Gear2 = 0.1; #[kg] Mass of Gear2
set: real R_Gear1 = 0.1; #[m] Radius of Gear1
set: real R_Gear2 = 0.3; #[m] Radius of Gear2

set: real K_GroundSpring = 5; #[Nm/rad] Stiffnes Coefficient of Ground Spring
#         attached to Gear2

set: real K_Gear1_Gear2 = 100000.; #[N/m] Stiffness Coefficient of Contact
set: real C_Gear1_Gear2 = 100.;    #[Ns/m] Damping Coefficient of Contact

#-----------------------------------------------------------------------------
# Intermediate Variables
set: real I_Gear1 = M_Gear1*R_Gear1^2./2.; #[kgm^2] Moment of Inertia of Gear1
set: real I_Gear2 = M_Gear2*R_Gear2^2./2.; #[kgm^2] Moment of Inertia of Gear2

#-----------------------------------------------------------------------------
# Reference Labels
set: integer Ref_Gear1 = 1;
set: integer Ref_Gear2 = 2;

# Node Labels
set: integer Node_Gear1 = 1;
set: integer Node_Gear2 = 2;

# Body Labels
set: integer Body_Gear1 = 1;
set: integer Body_Gear2 = 2;

# Joint Labels
set: integer JoRevp_Gear1       = 1;
set: integer JoRevp_Gear2       = 2;
set: integer JoTotp_Gear1_Input = 3;

# Force Labels
set: integer CoStr_Gear1              = 1;
set: integer CoStr_Gear2              = 2;
set: integer CoStr_Gear2_GroundSpring = 3;

#-----------------------------------------------------------------------------
# Scalar Functions
scalar function: "cubstep",
cubicspline, do not extrapolate,
-0.03, 0.00,
-0.02, 0.00,
-0.01, 0.00,
0.00, 0.00,
1.00, 1.00,
1.01, 1.00,
1.02, 1.00,
1.03, 1.00;

#-----------------------------------------------------------------------------
# References
reference: Ref_Gear1,
null,                 # absolute position
euler, pi/2., 0., 0., # absolute orientation
null,                 # absolute velocity
null;                 # absolute angular velocity

reference: Ref_Gear2,
0., 0., -R_Gear1-R_Gear2, # absolute position
euler, pi/2., 0., 0.,     # absolute orientation
null,                     # absolute velocity
null;                     # absolute angular velocity

#-----------------------------------------------------------------------------
# [Nodes Block]

begin: nodes;

#-----------------------------------------------------------------------------
# Nodes
structural: Node_Gear1, dynamic,
reference, Ref_Gear1, null, # absolute position
reference, Ref_Gear1, eye,  # absolute orientation
reference, Ref_Gear1, null, # absolute velocity
reference, Ref_Gear1, null; # absolute angular velocity

structural: Node_Gear2, dynamic,
reference, Ref_Gear2, null, # absolute position
reference, Ref_Gear2, eye,  # absolute orientation
reference, Ref_Gear2, null, # absolute velocity
reference, Ref_Gear2, null; # absolute angular velocity

end: nodes;

#-----------------------------------------------------------------------------
# [Elements Block]

begin: elements;

#-----------------------------------------------------------------------------
# Bodies
body: Body_Gear1, Node_Gear1,
M_Gear1,               # mass
null,                  # relative center of mass
diag, 1., 1., I_Gear1; # inertia matrix

body: Body_Gear2, Node_Gear2,
M_Gear2,               # mass
null,                  # relative center of mass
diag, 1., 1., I_Gear2; # inertia matrix

#-----------------------------------------------------------------------------
# Joints
joint: JoRevp_Gear1,
revolute pin,
Node_Gear1,
null,                             # relative offset
hinge, eye,                       # relative orientation
reference, Ref_Gear1, null,       # absolute pin position
hinge, reference, Ref_Gear1, eye; # absolute pin orientation

joint: JoRevp_Gear2,
revolute pin,
Node_Gear2,
null,                             # relative offset
hinge, eye,                       # relative orientation
reference, Ref_Gear2, null,       # absolute pin position
hinge, reference, Ref_Gear2, eye; # absolute pin orientation

joint: JoTotp_Gear1_Input,
total pin joint,
Node_Gear1,
position, null,                                  # relative offset
position, reference, Ref_Gear1, null,            # absolute position
rotation orientation, reference, Ref_Gear1, eye, # absolute rotation orientation
position constraint,
inactive, inactive, inactive,
null,
orientation constraint,
inactive, inactive, active,
single, 0., 0., 1., string, "2.*pi*3.*sin(2.*pi*Time/4.)*model::sf::cubstep(Time)";

#-----------------------------------------------------------------------------
# Plugin Variables
set: [element, AZ_Gear1, JoRevp_Gear1, joint, string="rz"];
set: [element, WZ_Gear1, JoRevp_Gear1, joint, string="wz"];
set: [element, AZ_Gear2, JoRevp_Gear2, joint, string="rz"];
set: [element, WZ_Gear2, JoRevp_Gear2, joint, string="wz"];

#-----------------------------------------------------------------------------
# Forces
couple: CoStr_Gear1,
follower,
Node_Gear1,
single, 0., 0., 1.,
string, "-K_Gear1_Gear2*(AZ_Gear1*R_Gear1+AZ_Gear2*R_Gear2)*R_Gear1\
-C_Gear1_Gear2*(WZ_Gear1*R_Gear1+WZ_Gear2*R_Gear2)*R_Gear1";

couple: CoStr_Gear2,
follower,
Node_Gear2,
single, 0., 0., 1.,
string, "-K_Gear1_Gear2*(AZ_Gear1*R_Gear1+AZ_Gear2*R_Gear2)*R_Gear2\
-C_Gear1_Gear2*(WZ_Gear1*R_Gear1+WZ_Gear2*R_Gear2)*R_Gear2";

couple: CoStr_Gear2_GroundSpring,
follower,
Node_Gear2,
single, 0., 0., 1.,
string, "-K_GroundSpring*AZ_Gear2";

end: elements;
```