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Transcript of Universal Mechanism Simulation of Tracked Vehicle Dynamics with Universal Mechanism @umlab.ru...
Universal Mechanism
Simulation of Tracked Vehicle Dynamicswith
Universal Mechanism
www.umlab.ru [email protected]
Universal mechanism
Universal Mechanism
Contents
Examples of tracked vehicle (TV) models
Main components of TV models
Development of a model of TV
Models of force elements
Simulation of TV dynamics
Universal Mechanism
Examples of TV models
Tank371 bodies, 1916 d.o.f.
TV of different types
Crawler transporter263 bodies, 1332 d.o.f.
Excavator138 bodies, 128 d.o.f.
Universal Mechanism
Examples of tracked vehicle (TV) models
Main components of TV models
Development of a model of TV
Models of force elements
Simulation of TV dynamics
Universal Mechanism
Main components of TV model
Sprocket
Rollers
Idler with tension device
Track links Suspension and road wheels
Components of a track model
Main system of coordinates for TV model
Universal Mechanism
Main components of TV model
Standard suspensions as subsystems
Torsion bar suspension Suspension bogie
Suspension torsion bogie Fixed suspension
Universal Mechanism
Main components of TV model
Standard models of idler with tension device
Simplified model of idler on a crank
Advanced model of idler on a crank
Idler on a slider
Universal Mechanism
Main components of TV model
RoRo Ro
r
Rs
h
μ/2
Ro
μ/2
h
Rs
LJ
RT
RP
r
Generator of sprocket tooth profile
Universal Mechanism
Main components of TV model
Standard track link models
Track link with rigid joint Track link with flexible joint (bushing)
Track link with two parallel bushings (double pin)
Universal Mechanism
Main components of TV model
User defined components Registration of a new component of TV
Universal Mechanism
Examples of tracked vehicle (TV) models
Main components of TV models
Development of a model of TV
Models of force elements
Simulation of TV dynamics
Universal Mechanism
Development of TV model
Track is generated automatically with the help of components from the database
Step.1 Setting track structure
Universal Mechanism
Development of TV model
Step.6 Completion of track model. Adding dampers
Dampers
Characteristics of shock absorber
Universal Mechanism
Examples of tracked vehicle (TV) models
Main components of TV models
Development of a model of TV
Models of force elements
Simulation of TV dynamics
Universal Mechanism
Models of force elements
Wheel-link interaction
S
R
δ
Normal contact force is proportional to the area S of penetration
SF
Universal Mechanism
Models of force elements
21
02
3
0 )()(,)(
cd
dFcPF
Wheel-link interaction
Force versus penetration model
Here δ0 is the deflection under the load P; c(δ) is the stiffness versus penetration law
Universal Mechanism
Models of force elements
Wheel-link interaction
The obtained relations are generalized for a contact of a wheel with a polyline corresponding to the track chain.
Universal Mechanism
Models of force elements
Restrictive force and moment
C
ht
T
yx
y αx
.
,
xaxxaxx
yyy
dcM
ydycF
The force and moment prevent the lateral shift and rotation of a link
Universal Mechanism
Models of force elements
Track-ground interaction
Two main model of the ground: Spring-damper model without sinkage Soil with sinkage
Contact point
Universal Mechanism
Models of force elements
Bekker ground model
nc zkb
kp
Here p is the normal link-ground pressureb is the minimal size on the contact patch b (length of a track link)n, kc , k are the model parametersz is the sinkage depth
Universal Mechanism
Models of force elements
Examples of terrain models
Normal force versus sinkage depth for different soils
Universal Mechanism
Models of force elements
Example of track load force versus sinkage by loading and unloading/reloading processes
Loading
Unloading/Reloading
Universal Mechanism
Модели силовых взаимодействий
Tangential strength(Janosi, Hanamoto)
Kjepczj 1tan),(
Here j is the shear displacement of the link since the first contact with soilp is the normal pressurec is the cohesion is the angle of internal frictionK is an empirical constant
Universal Mechanism
Examples of tracked vehicle (TV) models
Main components of TV models
Development of a model of TV
Models of force elements
Simulation of TV dynamics
Universal Mechanism
Simulation of TV dynamics
Dynamic analysis of TV as a set of tests
List of auxiliary tests:EquilibriumTrack tensionComputation of initial velocities
List of main tests:Vertical harmonic loadingStraight motionOpen loop steeringTest with driver:
2D curve 3D testing area
Universal Mechanism
Simulation of TV dynamics
Test: straight motion
Harmonic irregularities in opposite phase
Universal Mechanism
Simulation of TV dynamics
Тест: движение по прямой
In-phase harmonic irregularities
Test: straight motion
Universal Mechanism
Simulation of TV dynamics. Open steering test
Longitudinal speed 8 m/s Difference in sprocket speeds 0.7 m/s
Universal Mechanism
Simulation of TV dynamics. Open steering test
Longitudinal speed 0 m/s Difference in sprocket speeds 0.7 m/s
Universal Mechanism
Simulation of TV dynamics
Driver model: closed loop control for TV turning
Desired path
TV
Lp
x
y
)( dttyKV
Closed loop control
Universal Mechanism
Simulation of TV dynamics: testing area
Testing area is created in one of the CAD programs (SolidWorks, Inventor, PRO/E…)
A set of routes is specified by the user
Speed along the route can be variable
Universal Mechanism
Simulation of TV dynamics: test with driver
Testing area
Speed history along the route
Universal Mechanism
Simulation results
Any kinematic variables (trajectories, velocities, accelerations of any point, angles of rotation, angular velocities and accelerations of bodies) Plots of applied forces Plots of reaction forces Plots of special variables related to TV dynamics Animation files Special tools for multivariant calculations and processing of their results Factorial experiments
Universal Mechanism
Processor requirements
UM implements parallel computation of TV dynamics with the help of multithreading
It is strongly recommended to use
multi-core processors
The highest performance is achieved on eight-core processors
(four physical + four logical cores)
Universal Mechanism
Simulation of Tracked Vehicle Dynamicswith
Universal Mechanism
www.umlab.ru [email protected]
Universal mechanism