Project
PROJECT:
AIM:
To study and analysis the system level all terrain vehicle model(ATV) in simulink and observe results.
OBJECTIVE:
Prepare a technical report explaining the model properties & comments on the results.
ALL TERRAIN VEHICLE:
An all terrain vehicle (ATV) is defined as a motorized off highway vehicle designed to travel on four low pressure or non pneumatic tires,having a seat designed to be straddled by the operator and handlebars for steering control.ATV are subdivided into two types as designated by the manufacturer.type l ATVs are intended by the manufacturer for use by a single operator and no passenger.type ll ATVs are intended by the manufacturer for use by an operator and a passenger,and are equipped with a designated seating position behind the operator.
DISCRIPTION:
Components of a ATV(all terrain vehicle):
1.VEHICLE BODY BLOCK
The vehicle body block represents a two axle vehicle body in longitudind.the vehicle can have the same or a different number of wheels on each axle.the vehicle can also have a central of gravity that is at or below the plane of travel.
the block account for body mass,aerodynamic drag,road incline,and weight distribution between axles due to accelaration and road profile.optionally include pitch and suspension dynamics.the vehicle does not move vertically relative to the ground.
the block has an option to includes an externally difined mass and an externally-defined intertia.the mass inertia and centre of gravity of the vehicle body can vary over the course of simulation in responce to system changes.
2.CVT(CONTINUOUSLY VARIBLE TRANSMISSON)
CTV is a continuously variable transmission system.a continuously variable transmission is an automatic transmission that can change seamlessly through a continous rsnge of gear ratios.this contrasts with other transmission on that provide alimited number of gear ratio in fixed steps.cvt used in car,tractor,motor scooters,snow mobiles,bicycles and earth moving equipment.the most common type of CVT uses two pulleys connected by a belt or chain,however several other designs have also been used at times.
3.GENERIC ENGINE
The generic engine block represents a general internal combustion engine.this block is a suitable generic engine for spark-ignition and diesel.speed-power and speed-torque parameterizations are provided.a throttel physical signal input specifies the normalized engine torque.optional dynamic parameters include crankshaft intertia and responce time lag.a physical signal port outputs the engine fuel consumption rate based on the fuel consumption model that you choose.optional speed and readline controllers prevent engine stall and enble cruise control.
generic engine main port:
a.B-rotational conserving port repressenting the engine block.
b.F-rotational conserving port repressenting the engine crank shaft
c.T-physical siganl input port specifying the normalized engine throttel level.
d.P-physical signal output portreporting the instantaneous engine power in,W
e.FC-physicsl signal output port;reporting the fuel consumption rate in kg/s.
4.SUSPENSION
Suspension is the system of tires,tire air,springs,shock obserbers and linkages and allows relative motion between the ratio.suspension system must support both road holding/handling and ride quality.which are at odds with each other.
5.SIMPLE GEAR
The simple gear block represents a gear box that constrains the connected driveline axes of the base gear,B and the follower gear,f to corotale with a fixed ratio that is specified.
PORTS:
B-base: rotational mechnical conserving port associated with the base,or input,shaft.
F-follower :rotational mechnical conserving port associated with the follower,or output shaft.
6.VARIABLE GEAR RATIO
Represents a variable ratio gear box such as implementes by mechnical belt CVT electric or hydraulic transmission .the physical signal input r defines the ratio of inputs to output angular shaft velocities.connections b(base)and F(follower) are mechnical rotational conserving ports.specify the relation between base and follower rotation directions with the output shaft roatates parameter.
7.DOUBLE SHOE BRAKE
Represents a brake arranged as two pivoted rigid shoes symmetrically installed inside or outside a drum and operated by one actuator.the actuator force causes the shoes to exert a frition torque on a shaft connected to drum.
connection is a conserving rotational terminal associated with the drum shaft.connection f is a physical signal port represting the force input to the actuator.positive force creates friction torque that resists shaft rotation. optionally include thermal effects and expose thermal conserving port H by setting thermal port to model.
8.TIRE BLOCK
Represnts the longtudinal behavour of a highway tire characterized by the tire magic formula. the block is build form tire effects of tire intertia,stiffness and damping can be included.
conncection a is the mechnical rotational conserving port for the wheel axle.
connection H is the mechnical translational conserving port for the wheel hub through which the thrust developed by the tire is applied to the vehicle.
connection N is a physical signal input port that applies the normal force acting on the tire.
connection S is a physical signal output port that reports the tire slip.
MAIN MODEL ATV(ALL TERRAIN VEHICLE) EXPLAINATIOAN
The throttel signal is generated by signal builder block and inputted to generic engine.
The torque and speed vector are inputted from the matlab workspace.
The engine will generate the output RPM which can be taken from the crank shaft output.this speed will be given to the ideal rotational motion sensor to sense the output RPM.
The some ouput speed will be given to a simple gear mechnism to reduce the speed where the gear ratio is 4.
The output speed from the gear reduce will be given variable ratio on transmission block (CVT).
The cut ratio is provided to the variables ratio transmission (CVT) block through signal builder.
The speed is controlled by the variable CVT ratios and the controlled output speed is inputted to the vehicle axle.
The brake signal is generated by the signal builder and inputted to the vehicle body ( double shoe brake) fpr applying the brake to axle.
The power from the CVT is inputted to the axle and the vehicle accelerates according to the speed.
The velocity is taken as output from the vehicle body for further analysis.
THROTTLE INPUT SIGNAL
Throttle starts at 0.3 and then it steps to 1 at the 20th seconds.
BRAKE INPUT SIGNAL
The brake input remains zero through the whole simulation.
TORQUE AND SPEED MATLAB WORKSPACE INPUT
CVT RATIO INPUT
CVT ratio starts at 3.5 than 3 sec. if gradually reduces until it reaches 1 and 33th second and itremains so till the end of the simulation.
RESULTS
TORQUE SPEED PLOT
The torque and speed are inputted from the matlab workspace window to the generic engine blocks to generate the output RPM according. this plot behaviour is generic to all ICE.
ENGINE SPEED
The engine RPM generated according to the throttle,speed and torque inputs.it is clearly evident how to step increse in throttle at 200 sec. resulted in an incresed in the engine revolutions from 2110 to 3410 RPM.
ENGINE SPEED VS GEAR REDUCTION SPEED
the engine speed is reduced by the gear ratio 4.maximum RPM(before reducing)=3383 rpm was reduce to 958.25 rpm which can be verified by diving the 3833 by the gear reduction 4.
CVT SPEED REDUCTION
The engine reduced speed is controlled by various CVT ratios.for verification the maximum RPM is calculated at 1.8 gear ratio which is applicable from 35th second
SPEED VS THROTTLE
From the graph we can infer that brake is not applied during the drive cycle and the throttle is constant 0.3 till 20 sec. where it incresed from 0.3 to 1 from 20 sec where it remains constant thought out.with increase in throttle the vehicle sped incresd from 31 to 56 kmph