Project

• N_B is the number of teeth in the base gear.

• N_BF is the number of teeth in the follower gear.

Explanation:

• B is for rotational mechanical conversing port associated with the base or input shaft.
• F is follower rotational mechanical conversing port associated with the follower or output shaft

Variable Ratio Transmission Block:

The Variable Ratio Transmission block represents a gearbox that dynamically transfers motion and torque between the two connected driveshaft axes, the base and the follower.

When you choose to have the block ignore the dynamics of transmission compliance, it constrains the driveshafts to corotate with a variable gear ratio that you control. You can choose whether the follower axis rotates in the same or opposite direction as the base axis. If the follower and base axis rotate in the same direction, ω_F and ω_B have the same sign. If the follower and base axis rotate in opposite directions, ω_F and ω_B have opposite signs.

Transmission compliance introduces internal time delay between the axis motions. Unlike a gear, a variable ratio transmission does not act as a kinematic constraint. You can also control the torque loss caused by transmission and viscous losses.

Explanation:

• B is Base pulley or drive pulley.
• F is follower pulley or driven pulley.
• R is variable transmission ratio.

Vehicle body block:

The Vehicle Body block represents a two-axle vehicle body in longitudinal motion. The vehicle can have the same or a different number of wheels on each axle. For example, two wheels on the front axle and one wheel on the rear axle. The vehicle wheels are assumed identical in size. The vehicle can also have a center of gravity (CG) that is at or below the plane of travel.

The block accounts for body mass, aerodynamic drag, road incline, and weight distribution between axles due to acceleration 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 include an externally-defined mass and an externally-defined inertia. The mass, inertia, and center of gravity of the vehicle body can vary over the course of simulation in response to system changes.

Explanation:

Input:

• W-Physical signal input port for headwind speed.
• Beta-Physical signal input port for road incline angle.
• CG -Center of gravity Physical signal input port for road incline angle.
• M- mass Physical signal input port for the mass, in kg, of the externally-defined mass.
• J-external moment of inertia Physical signal input port for the moment of inertia, in kg*m^2, of the externally-defined mass.

Output

• V longitudinal velocity-Physical signal output port for vehicle longitudinal velocity
• NF front axel-Physical signal output port for vehicle longitudinal velocity
• NR Rear axel-Physical signal output port for normal force on the rear axle. Wheel forces are considered positive if acting downwards.

Converisng:

Conserving port associated with the horizontal motion of the vehicle body. Connect tire traction motion to this port.

Double Shoe Brake Block:

Explanation:

The Double-Shoe Brake block represents a frictional brake with two pivoted rigid shoes that press against a rotating drum to produce a braking action. The rigid shoes sit inside or outside the rotating drum in a diametrically opposed configuration. A positive actuating force causes the rigid shoes to press against the rotating drum. Viscous and contact friction between the drum and the rigid shoe surfaces cause the rotating drum to decelerate.

Double-shoe brakes provide high braking torque with small actuator deflections in applications that include motor vehicles and some heavy machinery. The model employs a simple parameterization with readily accessible brake geometry and friction parameters.

Limitations:

• Contact angles smaller than 45° produce less accurate results.

• The brake uses the long-shoe approximation.

• The brake geometry does not self-lock.

• The model does not account for actuator flow consumption.

Input:

• F-Actuating force,Physical signal input port associated with the applied actuating force.
• T-External fault trigger,Physical signal input port associated with the applied actuating force.

Conversing:

• S-Drum Shaft Rotation,Rotational conserving port associated with the rotating drum shaft.
• H-Heat flow,Thermal conserving port associated with heat flow.

Tire block:

The Tire (Magic Formula) block models a tire with longitudinal behavior given by the Magic Formula [1], an empirical equation based on four fitting coefficients. The block can model tire dynamics under constant or variable pavement conditions.

The longitudinal direction of the tire is the same as its direction of motion as it rolls on pavement. This block is a structural component based on the tire block.

To increase the fidelity of the tire model, we can specify properties such as tire compliance, inertia, and rolling resistance. However, these properties increase the complexity of the tire model and can slow down simulation. Consider ignoring tire compliance and inertia if simulating the model in real time or if preparing the model for hardware-in-the-loop (HIL) simulation.

Other Blocks Used:

• Solver Configuration-To specify the solver pramaters.
• Signal Builder- to input brake and throttle and cvt ratio.
• Simulink to PS Conventer-To covert simscape signal to simscape.
• Mechanical reference-To make all the components are damped.
• Rotational free end-It respesents a mechanical rotational port freely.
• Scope-To display different graphs.
• Lookup Table-To insert the cvt values
• Step-To increase or decrease an input value for a defined time travel.
• PS terminator-Terminator for unconnected physical signal outputs.
• Knob-To increase decrease and vise versa of the thrrotle and brake inputs.

BAJA ATV Model without dashboard:

Model:

Explanation:

The throttle signlas are generated by the signal builder block to generic engine.The torque and speed vector are inputted from the matlab workspace.Thn the engin will generate the output rpm which can be taken from the crankshaft output.The speed will be given to IDeal rotational motion sensor to sense the rpm.

The same speed will br given to a simple gear to reduce the speed and the ratio of the gear is 4.The output speed from the gear will be given to variable ratio transmissiopn block(CVT).The speed is controlled by the variable CVT ratios and the controlled output speed is inputted to the vehicle axel.

The brake signal is generated by the signal builder and inputted to the vehicle body the brake to axel.The power from the CVT is inputted to the axel and the vehicle accelerates according to the speed.Then the velocity is taken as output from the vehicle body for futher analysis.

Input Signals:

Throttle starts at 0.3 and then it steps to 1 at he 20th second

THE b rake input remains zero through the whole simulation

torque and speed values in the matlab workspace:

Cvt ratio:

Engine sensor Sub block:

The above image is the engine sublock this measure engine rotational speed as it takes the output of the engine as its input and the outputs engine rpm.

CVT subblock:

This subblock provides theninput and thr output shaft of the cvt with inertia and the measure the inputs shaft rpm and the output shaft rpm.

Vehicle body subblock:

The above model shows tha thte vehicle is rear wheel drive as the output from the gear box is inputted to the axle theen an inertia is added to simulate axel inertia the brake shoe it has a s conversing port as discussed above its connected to the axle,and then the same axle connects the two rear tyres is free to rotate on a rotational free end.All the tyres H hub port is connected together and then connected to the vehicle body NR output ports,While the front are connected to thr NF vehicle body outputs ports,the vehicle body takes the road inclination and the wind velocity from thr physical constants.

Results:

Torque speed plot:

The torque and speed are inputted from the matlab workspace windows to the generic engine block to generate the output RPM accordingly the plot behaviour is generic to all ICE.

Engine speed plot:

The above plot show that the engune rpm generated accoeding tot the throttle speed ands torque inputs the increase in throttle at 20th second resulted in an increase in the engine revolutions from 2250 to 3800 RPM cause all the baja vehicle are of maximum within 4000RPM.

Engine speed vs Gear reduction speed plot:

The above plot shows that we can see that the engine speed is reduced by the gear ratio 4

CVT speed reduction plot:

The engine reduced speed is controlled by various CVT ratios.The maximum RPM is calculated at 1.8 gear ratio which is applicable from the 35thsec.

CVT RATIO =1.18

Maximum RPM = 958.25

Gear ratio = driven/driver

1/1.8=driven/958.25

driven = 958.25/1.8

driven =532.36RPM

the reduced rpm is 532.36

Speed VS throttle plot:

From the above graph we can infer tha the brake is not applied during the drive cycle and the throttle is constant to 0.3 to 20sec and being increased from 0.3 to 1 from 20 sec where it remains constant throughout witht increase in throttle the vehicle speed increased from 30 to 55kmph.

BAJA ATV model DATA EXTRACTION(CVTModel_data)

Model:

Explanation:

The above model is similar tot he previously discussed model theres a small addition is there the CVT ratio and vehicle speed data are extracted using to workspace block.

Results:

The results are same as BAJA ATV model without dashboard but an additional output is the CVT Ratio and Vehicle Velocity to workspace in matlab.

Workspace:

BAJA ATV Model with Dashboard(cvtModel_dashboard)

Model:

Explanation:

The model workflow is similair to BAJA ATV model without Dashboard but the throttle and brake inputs are controlled by the user with knobs.

Dashboard:

User controls:

Results:

Engine speed :

Here the speed of the engine is generated according to the inputs like throttle brake torque and speed vectors.The runtime is not defined so that the throttle and brake are controlled buy the user.The step up is throttle and step down is brake input.

Engine speed VS Gear reduction speed plot:

The engine speed is reduced byt he factor of 4 at any moment in the drive cycle as it is evident by the curve.

CVT speed reduction plot:

The CV gear reduction plot shows that at a cinstant reduction ratio of 1.8 the applicable at these large time frame and it can be verified by taking 689 as constant RPm adn to divide by 1.8 which gives us 383 RPM thats what showed in the plot.

Speed VS throttle :

From the graph we can infer that the vehicle is accelerating while throttle is applied and decelarated while break is appied .The constant speed areas represents no changes in throttle or braking.

BAJA ATV MODEL mapped lookup table witout dashboard

Model:

Explanation:

The model workflow process is similar to the above prosess without dashboard expect that it used instead of signal builder blocks for brake and throttle the step value is o and at 20 sec throttle input will increase from 0.3 to 1 then remains constant throught the process.

Brake input:

Throttle input:

CVT SUBBLOCK:

Explanation:

The CVt Subblock is the same as the previous model BAJA ATV model without dashboard but instaed of signal builder block fo CVT ratio 2D lookup table is used the file name as Lookuptable_data.mat.

Lookup table:

A lookup table is an array of data that maps input values to output values, thereby approximating a mathematical function. Given a set of input values, a lookup operation retrieves the corresponding output values from the table.

• Interpolation is a process for estimating values that lie between known data points.
• Extrapolation is a process for estimating values that lie beyond the range of known data points.
• Rounding is process for approximating a value by altering the digits according to a known rule.

Given input values simulink performs a lookup operation to retrive hte corresponding output values from the table. If the lookup table does not define the input values the block estimates the output values based on nearby table values.

At last the vehicle speed output is given as a feedback to the 2D table so that we cab verify.

Results:

CV ratio plot:

We compare the above plot the ratio varied from 2.3 to 1.8 within a timespan of 80 sec which is same the previous BAJA ATV and from 32 sec its constant ratio of 1.8 compared to 35 sec in the first model.

CVT ratio vs Vehicle velocity:

0 to 20 kmph the cvt ratio is 2.3

20 to 30 kmph cvt ratio down to 2.03

30 to 50 kmph the cvvt ratio drops down to 1.8

50kmph and above the cvt ratio is cinstant at 1.8

Where we can conclude that bthe vehicle accelerates, decelerates and remains constant when the CVt ratio is being varied.

Engine Speed:

The above graph is similar to first model

CVT SHAFT SPEED:

The output shaft speed is similar to the first plot

Speed vs throttle plot:

BAJA ATV MODEL MAPPED LOOKUP TABLE WITH DASHBOARD(cvtModel_dashboard_mapped):

Model:

Dashboard:

Explanation:

The model workflow is same as the process of baja atv model mapped lookup table without dashboard but the throttle and brake inputs are controlled by the user with the knob followed by the vehicle speed is given as feedback.

Results:

CVT ratio plot:

In this BAJA ATV model the engine is pre set to run at 3300 rpm with the throttle value of 0.3 and the velocity at 45kmph.CVT has maximum speed of the engine is perdinined as 2.3 and 1.8. When the simulation is satrted then initial throttle value 0.3 is achiched so thart the CVT ratio is 1.85.Increase in throttle is being increased the CVT ratrio towards 1.8 While braking is applied the CVT ratio increase so that it can achieve the nearest stae of 2.3

Engine speed plot:

the above graph we can se that the vehicle was firat running at an rpm of 3300 adn then throttled and then braking applied then brake is released so that the engine rpm is increased again.

CVT SPEED reduction plot:

Speed vs throttle:

From the above plot we can see that when the throttle is applied the vechile speed increase and when brake is applied vehicle speed decreased simultaneously.