Project
AIM : To prepare a technical report of all terrain vehicle (ATV) under different conditions
Objectives: carry out a system level simulation of all terrain vehicle and prepare a technical report explaining the model properties and comments on the results
case 1: ATV model without dashboard
case 2: ATV model with dashboard
case 3: ATV model using lookup table
case 4: ATV model using lookup table with dashboard
ALL-TERRAIN VEHICLE (ATV):
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
Continuosly variable transmission(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 transmission systems are also known as single-speed, shiftless, and stepless transmissions. The shiftless nature of a CVT offers unparalleled flexibility that maintains constant angular velocity regardless of output speed. Additionally, a continuously variable transmission makes accelerating smooth and offers enhanced fuel economyCVTs are used in automobiles, tractors, motor scooters, snowmobiles, bicycles, and earthmoving 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
ATV model consists of CVT , generic engine ,vehicle body ,engine sensor ,signal builder ,variable ratio gear and simple gear,scopes and solver configuration ,inertia ,motion sensors,double drum break,lookup table ,tyres etc
Generic engine:
Represents a system-level model of spark-ignition and diesel engines suitable for use at initial stages of modeling when only the basic parameters are available. Optional idle speed and red line controllers are included
The throttle input signal T lies between zero and one and specifies the torque demanded from the engine as a fraction of the maximum possible torque. If the engine speed falls below the Stall speed, the engine torque is blended to zero. If the engine speed exceeds the Maximum speed, the simulation stops and issues an error message.Connections F and B are mechanical rotational conserving ports associated with the engine crankshaft and engine block, respectively. Connections P and FC are physical signal output ports through which engine power and fuel consumption rate are reported
Vehicle body:
Represent a two axle vehicle body in longitudinal motion the block accounts for body mass aerodynamic drag and road incline weight distribution between axles due to acceleration and road profile the vehicle have same or different no.of wheels on each axle include pitch and suspension dynamics or additional mass and inertia it consists of four wheels ,two wheels at rear end and two at infront of the body the rear wheel is connected to double shoe brake
simple gear:
Represents a fixed-ratio gear or gear box. No inertia or compliance is modeled in this block. You can optionally include gear meshing, backlash, and viscous bearing losses.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. Optionally include thermal effects and expose thermal conserving port H by setting Friction model to a temperature-dependent setting
engine sensor:
This sensor is connected with generic engine consists of physical model port block for subsystems ,ideal rotational sensor block measures the angular velocity ,ps terminator block is used to terminates the physical signal outputs the sensor is further connected to CVT susbsystem
Case 1: ATV model without dashboard
Signal builder:Brake input is constant zero throughout the given sample time which is 80sec and throttle input is 0.5 for 20seconds later it increases from 1 for the remaining time vehicle speed depends on the cvt ratio
Vehicle speed : While the providing the throttle input we observed the if valies is 0.3 is considered then the velocity shows the sudden drop in yhe speed hence we changed it to 0.5 to get smooth flow of velocity
CVT shaft speed : The cvt shows the variations with respect to the primary and secondary RPMs based on the gear ratio
Case 2: ATV model with dashboard
This model is similar to the previous model the extra one is added over here is dashboard which has brake and throttle input knobs that allows user to change the input values while the simulation is running
We kept the brake input as zero wheras the throttle keep varying by the user by increasing or decreasing and impact on the vehicle speed
The change in throttle inputs results in the changes in the vehicle speed
Vehicle speed: brake input is 0 and the throttle input is variable with the help of the knob the change in the throttle input reflect in the velocity as well from the graph the throttle input is increased the speed is increased and vice versa for the decrease in throttle input
Cvt shaft speed: the cvt shows the variations with respect to the primary and secondary RPMs based on the gear ratio
Case 3: ATV model using lookup table
In this model the brake and throttle use a step a signal as an input having the lookup table with cvt ratio vs vehicle speed as a visualisation table helps to specify the cvt ratio then the model runs for the 200 second and gave the output in the various plots they are vehicle speed and cvt shaft speed. The lookup plot and cvt ratio plot is similar
Vehicle speed: the brake input is zero and the throttle input is 0.3 for 20 second later rest on 1 the velocity of the vehicle increase for 20 sec later on it increases from 40 seconds till speed gets stable
CVT shaft speed: the cvt shows the variations with respect to the primary and secondary RPMs based on the gear ratio
Case 4: ATV model using lookup table with dashboard
This model is similar to the previous model the extra one that is added over here is the dashboard along with lookup table here the inputs can be given using the knobs on the dashboard for brake and throttle input then simultaneous changes will shows the impact on the vehicle speed here the brake input is zero and throttle input can be increased or decreased during simulation varying by the user
We simulated this for inf period and gave throttle input to get the final results
Vehicle speed: from the graph the throttle is increased the speed is increased and vice versa for the decrease in the throttle input the input is zero throughout the simulation and throttle is varying by the user and the vehicle shows changes with reference to the throttle input
CVT shaft speed: the cvt shows the variations with respect to the primary and secondary RPMs based on the gear ratio
CONCLUSION : we ran the system level simulation for a All - terrain vehicles (ATV) model using CVT with or without dashboard and lookup table based on the above obtained results