Project

Aim:-

         To study the system-level simulation of an all-terrain vehicle under different conditions using Simulink.

Objectives:-

• To study the Baja ATV model without a dashboard.
• To study the Baja ATV model with a dashboard.
• To study the Baja ATV model using a lookup table without a dashboard.
• To study the Baja ATV model using a lookup table with a dashboard.

What is All Terrain Vehicle:-

                  The term ATV stands for All-Terrain Vehicle. It is also known as a quad or quadricycle type vehicle. An All-Terrain motor vehicle could have three, four, or even six wheels. Unlike a motorcycle, generally, ATVs have more than two wheels. This vehicle runs on low-pressure tires. However, it has handlebars instead of wheels for controlling the steering. As the name indicates, an ATV is designed to handle a broader variety of terrain than regular vehicles. In some countries, it is a street-legal motor vehicle and licensed for use on public roads. However, it is not street-legal or roadworthy within some states, territories, and provinces of some countries.

                                       fig. ATV

 For case 1: To study the Baja ATV model without a dashboard

Simulink Model:-

 

 The above block diagram represents the Simulink model of BAJA ATV where we use subsystems which are CVT, engine sensor, and vehicle body. Also, we used blocks like the signal builder, from goto blocks, scope, generic engine, mechanical rotational reference, and simple gear.

The major components used in the model are as follows.

1. Continuously variable Transmission (CVT):-

The above block represents the CVT system in the ATV model.

It consists of following blocks:

1. Primary pulley
2. Variator
3. Secondary pulley 
4. Belt

So the variator which is connected to the primary pulley when it goes outwards, the variator of the secondary pulley goes inward 

So Rp

and when the variator is connected secondary pulley when it goes inwards, the variator of the primary pulley goes inwards 

It became Rp>Rs which leads to overdrive.

Inside CVT we have input shaft inertia and output shaft inertia, which is representing the primary and secondary pulley. To specify the gear ratio we have a variable gear ratio block. Then with that, there is a primary and secondary RPM sensor.

2. Vehicle Body:

The above Simulink bock represents the vehicle body of the ATV. 

In this block we can specify our car's mass number of wheels per axle, Horizontal distance from CG to the front axle, the horizontal distance from CG to the rear axle, CG height above the ground we can also include the drag here. Here the data feed is simple we can feed the data on a practical based to get a better simulation of our own Baja model.

We used a simulation data inspector to compare the vehicle speed at different masses. Data inspector is a tool where we can run multiple simulations. To use this tool we need to log all the data.

3. Simple Gear

This block is a simple gear block. In this block, B is input and F is output.

 It is just the mechanical system used to set the gear ratio we are taking it as 4 . Because it is working fine and it is making the engine work to its fullest. With that gear ratio, we go quickly over rpm. 

4. Generic Engine 

 The above block is a generic engine where T is input and B is connected to the mechanical rotational reference and solver configuration and F is the output.

We have fed the data from the image by using the GRABIT command to our model from the engine torque-speed curve we feed the torque and the speed is 3840 rpm.

 5. Signal Builder  

The signal builder block is used to provide input values to the system, the values provided to the system are given below

For brake and throttle:

 Here for the brake, the input value provided is zero, and for the throttle, the given value is 0.3.

As in this, the brake value is zero so there are no power losses for the throttle.

For CVT gear ratio:

 

 Here is the input data of the signal builder for the CVT gear ratio.

For the first 4 sec, the 2.3 ratios are used for the next 4 to 35 the ratio is going down to 1.8 and is continues until 80.

Torque vs Engine speed input:

 The above curve represents the torque vs engine speed graph as we can see for the 3840rpm the torque is 7.8.

As the torque increases the engine speed increase.

Output for Case 1:-

The output we get after running this Simulink model for 200 sec is vehicle speed and CVT Shaft Speed.

For vehicle Speed:

 The above graph shows the graph of velocity distance throttle and brake. The brake input is zero therefore there is no effect on the vehicle speed.

AS we can see in the graph the brake input is 0 for the rest of the process and the throttle is at 0.5. The above curve shows that the vehicle attained its maximum speed v=55kmph at full throttle= 1 after 30 seconds then remain constant.

 For CVT Shaft Speed:

 The above curve represents the primary and secondary CVT RPM graph. These values differ with respect to the gear ratio.

 This graph has been shown that the variation in angular velocities of input and output shafts of the variable gear transmission system. 

For case 2: To study the Baja ATV model with a dashboard

Simulink Model:-

The above Simulink Model represents the BAJA ATV model with the dashboard. 

 In this model, knobs are used instead of signal builder blocks and these kh=nobs are connected with the circular gauge to show the rpm and velocity of the model.

 The brake input is starting from 0 to 0.5 and for the throttle input, the initial and final range is 0.3 to 1.

Output For case 2:-

For Vehicle speed:

The above graph is the output graph where we run our simulation for inf. time.

We can vary the throttle input with respect to that we get the speed. When throttle value is 0.5 and brake input is 0. When we increase the value of breaking then the velocity will decrease.

For CVT shaft Speed:

 

The above Graph represents the difference between primary and secondary CVT shaft speed.

For most of the time, primary and secondary CVT shafts are similar as we can see in the graph.

For Case 3: To study the Baja ATV model using a lookup table without a dashboard

Simulink Model:- 

 The above Simulink model represents the BAJA ATV model with a lookup table.

 In the above diagram, we didn't use the signal builder like we used in first two cases here we used a lookup table instead of a signal builder that's why our CVT subsystem will change.

CVT Block:-

 The only difference between this model and the previously studied model is we added a lookup table instead of using a signal builder block we provided the gear ratio input by using a lookup table. The vehicle velocity and shaft rpm are the same as before.

Lookup Table Visualization:-

The brake input and throttle input is given by step time, which depends on the run time and varies accordingly. By using a Lookup table for gear ratio which takes as input to the CVT and works according to the input gear ratio and obtained the output. This method is very effective which can avoid unusual torque at a certain speed and very easy to achieve greater velocity & engine speed. It works as a closed-loop when the input is given by the lookup table. The Simulink gets the input value from the lookup table and obtains the result according to the input values of the gear ratio. The gear ratio varies from 2.3 to 1.8 as taken as input and output in terms of velocity. The maximum velocity reached as
57kmph approximately.

Output for case 3:-

The output we get after running the simulation is the vehicle speed and CVT shaft in rpm.

For Vehicle Speed:

Here the brake input is zero and throttle input is 1 so there are no power losses.

As we increase the throttle the velocity increases cause distance covered as shown in the above graph.

For CVT shaft:

The above graph shows the difference between CVT primary and secondary rpm. The secondary CVT rpm is more than CVT primary rpm as we can see in the above graph.

At the starting of both curves, there is a small deflection but after 10 both curves are in stable condition. 

For Case 4: To study the Baja ATV model using a lookup table with a dashboard

Simulink Block:-

The above Simulink block represents the BAJA ATV model with a lookup table and dashboard. We were using some random values to the CVT as we can see in the dashboard the values are for brake input is zero and throttle input is 0.6 and we were checking the vehicle speed and it is not realistic because the CVT ratio is depending upon the vehicle velocity. So then we used this model which is a closed-loop model which has been built using the LOOKUP table. There is feedback coming from velocity if you go inside the CVT block there is a lookup table so based on the data given to the lookup table it is calculating the required amount of CVT ratio. And we are controlling throttle and brake input with the knobs.

Output For case 4:-

The output we get after running the program is CVT ratio vehicle speed and CVT shaft speed.

For Vehicle speed:-

This is similar to the CVT dashboard case. The variation in the vehicle velocity can be observed when we change or increase the throttle input. The velocity will increase and if we decrease the throttle input and increase the breaking input the velocity of the vehicle will decrease the reduction of speed will occur. And the vehicle will stop if the breaking input is high.

For CVT shaft Speed:-

This graph indicates the variation in rpm of primary and secondary shafts with respect to input parameters. The variation between the two curves is almost similar.

Result:-

      With the help of Simulink, we successfully studied all the cases as given in the objectives. All the output and the results are mentioned below in their particular cases. 

Conclusion:-

     With the help of Simulink, we successfully analyzed all four parameters off BAJA ATV with CVT and we get all the results with respect to the vehicle speed and CVT shaft rpm.