Project

Aim:

• perform the system level simulation of the baja all terrain (ATV) model that uses the CVT model and analyze the model.

Objective :

• study the open and closed loop ATV model
• understand the lookup table and dashboard block that enhance the performance of simulink model

What is CVT ?

A continuously variable transmission (CVT) is an automatic transmission that can change seamlessly through a continuous range of gear ratios. This contrasts with other transmissions that provide a limited number of gear ratios in fixed steps. The flexibility of a CVT with suitable control may allow the engine to operate at a constant RPM while the vehicle moves at varying speeds

cvt Block consists of following block under the mask :

to facilitate the step less design of the CVT,variable gear is implemented in model and input to the block decide by the actual gear ratio.the actual gear ratio signals are build by the signal builder and that used as input to the variable gear ratio.rotational motion sensors are connected at the both side to get the angular velocity and angle data

Vehicle body consists following block under the mask :

Vehicle body Represents a two-axle vehicle body in longitudinal motion. body consisting of the mass 250kg ,drag ,pitch,CG and all the data that we can change as per vehicle requirements data.tire block in that all the tire data can be inserted,double shoe dreak block also there which represent the actual break consists of 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 friction torque on a shaft connected to the drum.input fo rthe whole block is break and output data from the CVT block.output from the block is velocity.

Engine and Simple gear : Here in system generic engine is used in that we can insert the actual engine parameter data.

to the generic engine throttle input signal passed using the signal builder.simple gear is used to connect engine and CVT.

Generic engine block used to model the engine.it gives speed vector and torque vector by extracing the data from speed and torque curve.

Lookup table :

benefits of the lookup tabe is mapping output to input given. the output data is linked to the curresponding input data using a data array defined in the lookup table.the relationship between the input and output is unknown.lookup table improve the accuracy and reduces the time.simulink can extract the data by interpolation and extrapolation.It can be implemented using the lookup table block

lookup table used in the model CVT ratio as output for respective input vehicle speed.The vehicle speed is fed back to the CVT subsystem where CVT ratio is calculated using the lookup table block. the visuvalization if the lookup table is used in two of the modle under study is shown below.

this data points were created by simulating the model (not using a lookup table) for various vehicle speeds and the CVT ratio recorded

DASHBOARD ELEMENTS :

Dashboard elements more interacts with users,Dashboard are allowed us to give input and observe the output instantaneously during the run time of the simulation.two bloxk are used knob and custom gauage.using the knob brake and throttle input are applied.using the custom gauges RPM and velocity of vehicle is observed

BAJA ATV open loop model

This is the ATV simplest form.inputs are created using the signal builder.the brake input are 0 and throttle values are0.3 upto 20 sec and get 1 after 20 sec to the last.

below given are the output plots comes after running the for 200 sec

Results:

Dashboard BAJA ATV open loop model :

This same as the open loop model just and dashboard that get the input from the model instantly shows the output on custom gauges.

Results:

the above plots are the ouputs and that interact as knob moves of throttle and brake.

as knob moves throttle and brake input for the CVT block changes.

in CVT shaft graph secondary RPM data changes linearly with primary RPM data.

BAJA ATV closed loop model :

In the closed loop system input of the throttle and brake signal provided by the step block.

And the output of the vehicle body passes as input to the CVT block

Results:

Dashboard closed loop AVT model :

Same as the closed loop system ouput of the vehicle body block is used as the input for CVT block.

Dashboard used to give input by moving the knob instantly output changes which is showing using cutomized gauges.

Results:

After moving the knob of throttle and brake output velocity changes.CVT primary RPM changes linearly with secondry RPM

Conclusion :

This above CVT system is iteractive and also we can analyze with the real time data and understand the effect on the velcity.dashboard helps to take the data instantanously.