• All-Terrain Vehicle (ATV):

As per American National Standards Institute (ANSI) the All-Terrain Vehicle (ATV) also called as quad or quadricycle type vehicle or light utility vehicle (LUV). This type of motor Vehicle could have three, four, or even six wheels. This would be differentiate ATV from motorcycle. Basically ATV used to runs on low-pressure tires and also it has handlebars to control steering. It is single operator only although some companies have developed ATVs intended for use by the operator and one passenger.

Figure 1: Quadricycle type ATV.

• History [1]-[3]:

Figure 2: History of ATV.

In the early 19th century futuristic All-Terrain Vehicles journey started, in 1893, first powered quadricycle ATV model manufactured and sold by Royal Enfield. This model employed many bicycle components, such as handlebars. However, manufacturers mainly designed it as a horseless carriage for road use. Then in 1961 Jiger Corporation in Toronto started mass-production of six-wheeled amphibious ATV. But it will ended in 1968 due to the weak financial conditions of the company. A group of students first designed a three-wheeled ATV or Tri-cartin 1967 as a college project. First sit-on straddle-ridden three-wheeled ATV introduced by Honda in 1969, known as a US90. To make sustainable in environmental balloon tires utilized and to compensate for a lack of mechanical suspension. In 1982, Suzuki developed four-wheeled ATVs, LT125, which was a recreational machine for beginners. In 2011 LandFighter was founded, "the first Dutch/European ATV brand". The largest part of production takes site in Taiwan, to European standards; the ATVs are finally assembled in the Netherlands. Earlier it is used for entrainment, sports and agriculture uses but now days it used for armed/defense purpose also as per report published in [4].

BAJA All-Terrain Vehicle (ATV) Model:

Figure 3: BAJA ATV Model

• Components in Model:

1. Vehicle Body

Ports,

NR - Rear Axle Normal Force (N)

NF - Front Axle Normal Force (N)

Beta - Road Incline Angle Brad)

V - Longitudinal Velocity (m/s)

W - Head Wind Speed (m/s)

H - Horizontal Motion

Figure 4: Vehicle Body

DOUBLE SHOE BRAKE: - This type of brake mostly used in motor cycle and it has one drum and two shoe around it as shown below in figure. Unlike single shoe brake due to double shoe remove unbalance force.

Figure 5: Double-Shoe Brake

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.

PORTS, i. S - Rotational conserving port associated with the rotating drum shaft ii. F - Physical signal input port associated with the applied actuating force

PORTS:

N - Normal Force ii.

S - Tire Slip iii.

A - Axle iv.

H - Mechanical translational port associated with the wheel hub that transmits the thrust generated by the tire to the remainder of the vehicle.

1. Tire

The vehicle body is connected to 4 tires each per axle to move the vehicle according to the power input to the axle.

Figure 6: Tire simscape model

1. Engine: 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 throttle physical signal input specifies the normalized engine torque. Optional dynamic parameters include crankshaft inertia and response time lag. A physical signal port outputs the engine fuel consumption rate based on the fuel consumption model that you choose. Optional speed and redline controllers prevent engine stall and enable cruise control.

Figure 7: Engine simscape model and its block parameter

Ports:

B - Rotational Conserving Port representing the Engine Block

F - Rotational Conserving Port representing the Engine Crankshaft

T - Physical signal input port specifying the normalized engine throttle level

P - Physical signal output port reporting the instantaneous engine power, in Watts (W)

FC - Physical signal input port reporting the fuel consumption rate, in kg/s

Engine Sensor:

Figure 7: Engine Sensor

Two parameter used to in engine 1. Speed vector and 2. Torque vector. Which are generated from following graph. By using GRABIT [7] we can extract data points from graph. That extracted data points of figure () feed in generic engine.

Figure 8: Engine Torque vs Speed plot

• CVT- Continuous Variable Transmission:

A continuously variable transmission system is a type of automatic transmission in which an arrangement of pulleys and belts made it possible for a drive to achieve n-number of continuous gear ratios within a range (depends on the design).

Figure 9: CVT

Reference: https://www.mechanicalbooster.com/2018/12/how-cvt-works-continuously-variable-transmission.html

It consider two types of pulley having variable diameters that help the transmission achieve infinite gear ratios.

Driver pulley: connected with Engine

Driven pulley: connected with rare tire

To transfer power from engine to the final drive that are two shafts:

Input shaft: it is a type of shaft having splines over its cross-section over which input pulleys are mounted, the power source for this input shaft is engine

Output shaft: kept parallel to the input shaft, it also has splines over its cross-section and is mounted upon by output pulleys.

Two shafts are connected with belt

Belt or Chain- v-shaped metallic (rubber in some case) chain or belt is used to transmit power from input pulleys to the output pulleys as

V-shape of this belt or chain make it possible to shift gears from high torque to the high speed.

Figure 10: CVT

References: https://www.youtube.com/watch?v=gOFweQcz0XI

Figure 11: CVT

References: https://www.youtube.com/watch?v=PUOGBLHktW4

Two pair of conical pulleys each for input and output shafts are used in a basic continuously variable transmission that are-

Pulley on input Shaft		Pulley on Output Shaft
Fixed input pulley	Feeding input pulley or sheave	Fixed output pulley	Feeding output pulley or sheave
-Mounted over the input shaft on RHS -Not moveable, but rotates with the input shaft -Smaller in size	-Conical pulley -It has inner splines meshed with the shaft splines -The too and fro moment of this shaft over the input shaft make it possible to shift gear ratios	-Mounted over the output shaft on LHS -Not moveable, but rotates with the output shaft	-Same as moving input pulley - Placed on the RHS over the output shaft

Figure 12: CVT block Made in Model using simscape

To connect engine and CVT we need some speed reduction so we used Simple Gear ratio block, Simple gear of base and follower wheels with adjustable gear ratio, friction losses, and triggered faults.

The gear ratio is defined as,

Gear Ratio = Follower. Gear. Speed Base. Gear. Speed

PORTS,

1. B - Base Gear or Driver Gear F - Follower Gear or Driven Gear

Variable Ratio Transmission:

Represents a variable ratio gearbox such as implemented by mechanical belt CVT, electric, or hydraulic transmissions. The physical signal input r defines the ratio of input to output angular shaft velocities.

Connections B (base) and F (follower) are mechanical rotational conserving ports. Specify the relation between base and follower rotation directions with the Output shaft rotates parameter.

Other Blocks used in model:

• Signal Builder - To input the Brake, Throttle and CVT Ratio.
• Simulink to PS converter - To convert the Simulink signal to Simscape environment
• Solver Configuration - To specify the solver parameters before starting the simulation.
• Mechanical Reference - To make sure all the components are clamped to the ground.
• Generic Engine - To run the engine with speed and torque values as input
• PS to Simulink Converter - To convert Simscape signal to Simulink environment
• Scope - To view the graph of the parameters for better understanding.
• Display - To view the calculated engine power.
• Inertia - To represent the solid inertia.
• Rotational Motion Sensor - To sense the rotational motion from the engine and give output as RPM.
• Variable Gear Ratio - To vary the speed according to the gear ratios.
• PS Terminator - Terminator for unconnected physical signal outputs.
• Double Shoe Brake - To apply brake to the vehicle when needed.
• PS Constant - Generate constant physical signal.
• Tire - For transportation of the vehicle.
• Rotational Free End - For mechanical component (Tire)
• Vehicle Body - To represent the BAJA ATV model body.
• Custom Measure Gauge - To measure the brake and throttle input.
• Knob - To increase, decrease and vice-versa of throttle and brake inputs.
• Lookup Table - To insert the CVT values from the workspace.
• Simple Gear - To reduce the speed of the engine with pre-defined gear ratio.
• Step - To increase or decrease an input value for a defined time interval.

Types of Model:

1. BAJA ATV model (Open loop)
2. BAJA ATV model with Dashboard (Open loop)
3. BAJA ATV model (Close loop)
4. BAJA ATV model with Dashboard (Close loop)

BAJA ATV model (Open loop)

• Input and output for model as shown in below figure:

1. Brake input
2. Throttle input

Brake input given to almost zero and throttle input 0.3 for 0 to 20 second and after 20 seconds it is constant at 1.Here signal builder is used to generator this kind of signal.

Figure: inputs are for model

So based on Inputs the speed is vary, at 20 seconds when throttle increasing speed is also increasing and around 35 sec speed is going to stable at 55 km/hr.

Figure: Speed as output for model

Output:

Figure: Engine speed plot

Figure: Engine speed before and after speed reduction

Figure: CVT speed reduction

Figure: vehicle acceleration

• BAJA ATV model without Dashboard (open loop)

Figure: Engine speed plot

Figure: Engine speed before and after speed reduction

Figure: CVT speed reduction

Figure: vehicle acceleration

Figure: Throttle and Speed graph

• BAJA ATV model (Close loop)

• BAJA ATV model with Dashboard (Close loop)

Figure: CVT ratio plot

Figure: Engine speed

Figure: Engine speed before and after speed reduction

Figure: Throttle and Speed graph

References:

1. https://www.offroad-ed.com/indiana/studyGuide/A-Brief-History-of-ATVs/40101602_171153/
2. https://carbiketech.com/all-terrain-vehicle-atv/
3. https://en.wikipedia.org/wiki/All-terrain_vehicle
4. https://indianexpress.com/article/explained/explained-articulated-all-terrain-vehicles-indian-army-7840545/
5. https://www.youtube.com/watch?v=PUOGBLHktW4
6. https://www.mechanicalbooster.com/2018/12/how-cvt-works-continuously-variable-transmission.html
7. https://www.mathworks.com/matlabcentral/fileexchange/7173-grabit