Vehicle#

Car#

MyCar Class#

The MyCar class represents a complete vehicle dynamics simulation model. It integrates various subsystems essential for vehicle behavior simulation, including the chassis, wheels, and suspension components.

The class is composed of the following subclasses:

Chassis: Represents the main body of the vehicle, including mass, dimensions, and inertia properties.
Wheel: Four instances of the Wheel class represent the front-left, front-right, rear-left, and rear-right wheels.
Suspension: Four instances of the Suspension class simulate the dynamic response of the suspension system at each wheel.

class pymycar.Vehicle.car.MyCar(chassis=None, left_rear_wheel=None, right_rear_wheel=None, left_front_wheel=None, right_front_wheel=None, left_rear_suspension=None, right_rear_suspension=None, left_front_suspension=None, right_front_suspension=None, path=None, result_folder_name='results')[source]#

Bases: object

The MyCar class integrates the vehicle dynamics subsystems: chassis, wheels, and suspensions.

Attributes:

chassisChassis: Represents the main vehicle body.
left_rear_wheelWheel: Instance of the Wheel class for the rear-left wheel.
right_rear_wheelWheel: Instance of the Wheel class for the rear-right wheel.
left_front_wheelWheel: Instance of the Wheel class for the front-left wheel.
right_front_wheelWheel: Instance of the Wheel class for the front-right wheel.
left_rear_suspensionSuspension: Instance of the Suspension class for the rear-left suspension.
right_rear_suspensionSuspension: Instance of the Suspension class for the rear-right suspension.
left_front_suspensionSuspension: Instance of the Suspension class for the front-left suspension.
right_front_suspensionSuspension: Instance of the Suspension class for the front-right suspension.

Methods

__init__(chassis, left_rear_wheel, right_rear_wheel, left_front_wheel, right_front_wheel, left_rear_suspension, right_rear_suspension, left_front_suspension, right_front_suspension)	Initializes the MyCar instance with provided subsystem objects.
save_log_info(logger)	Logs the simulation parameters of the vehicle and its subsystems.

save_log_info(logger)[source]#

Log the simulation parameters of the vehicle and its subsystems.

Parameters:

loggerlogging.Logger: An instance of a logger to log the details.

Notes

The logger outputs detailed information for the following components: - Chassis - Each of the four wheels - Each of the four suspension systems

save_state_2_text_file()[source]#

Chassis#

Chassis Class#

The Chassis class represents the physical properties and state of the vehicle’s chassis in the simulation. It includes geometric dimensions, mass, inertia properties, and aerodynamic characteristics.

#
#       |<--rear_axle_to_com-->|<--front_axle_to_com-->|
#
#       |.....|
#   |---|.....|-------------\  |                       |
#   |     / \                \-----------------------|...|--------|   ---
#   |      |                                                      |   / \ 
#   |      |                                                      |    |   
#   |      |                                                      |    |
#   |      |                   com                                |    |
#   |  rear_track              *                                  |   front_track   
#   |      |                                                      |    |
#   |      |                                                      |    |
#   |      |                                                      |    |
#   |      |                                                      |   \ /
#   |     \ /                /-----------------------|...|--------|   ---
#   |---|.....|-------------/                    
#       |.....|
#
#

Parameter	Description
front_axle_to_com	distance between the front axle and the vehicle CoM
rear_axle_to_com	distance between the rear axle and the vehicle CoM
wheelbase	front_axle_to_com + rear_axle_to_com
front_track	front track
rear_track	rear track
com_height	CoM height
total_mass	total mass of the chassis
inertia_x	x-axis vehicle inertia (w.r.t. CoM)
inertia_y	y-axis vehicle inertia (w.r.t. CoM)
inertia_z	z-axis vehicle inertia (w.r.t. CoM)
drag_coefficient	aerodynamics drag coefficient
lift_coefficient	aerodynamics lift coefficient

class pymycar.Vehicle.chassis.Chassis(front_axle_to_com=None, rear_axle_to_com=None, front_track=None, rear_track=None, com_height=None, mass=None, inertia_x=None, inertia_y=None, inertia_z=None, drag_coefficient=None, lift_coefficient=None)[source]#

Bases: object

The Chassis class represents the physical properties and state of the vehicle’s chassis in the simulation. It includes geometric dimensions, mass, inertia properties, and aerodynamic characteristics.

Attributes:

front_axle_to_comfloat: The distance between the front axle and the vehicle’s center of mass (CoM). (default: 1.48 m)
rear_axle_to_comfloat: The distance between the rear axle and the vehicle’s center of mass (CoM). (default: 1.12 m)
wheelbasefloat: The total distance between the front and rear axles. It is the sum of front_axle_to_com and rear_axle_to_com.
front_trackfloat: The width of the chassis at the front axle, representing the distance between the left and right front wheels. (default: 1.71 m)
rear_trackfloat: The width of the chassis at the rear axle, representing the distance between the left and right rear wheels. (default: 1.62 m)
com_heightfloat: The height of the center of mass (CoM) from the ground. (default: 0.4 m)
massfloat: The total mass of the chassis. (default: 1400 kg)
inertia_xfloat: The moment of inertia about the x-axis (roll axis) of the vehicle, with respect to the CoM. (default: 400 kg·m²)
inertia_yfloat: The moment of inertia about the y-axis (pitch axis) of the vehicle, with respect to the CoM. (default: 2000 kg·m²)
inertia_zfloat: The moment of inertia about the z-axis (yaw axis) of the vehicle, with respect to the CoM. (default: 1320 kg·m²)
drag_coefficientfloat: The drag coefficient used for aerodynamic calculations. (default: 0.34)
lift_coefficientfloat: The lift coefficient used for aerodynamic calculations. (default: 0.0)

Methods

__init__(front_axle_to_com, rear_axle_to_com, front_track, rear_track, com_height, mass, inertia_x, inertia_y, inertia_z, drag_coefficient, lift_coefficient)	Initializes the chassis with the specified or default parameters.
update_state(dt)	Updates the chassis’s position and orientation based on the velocity and angular velocity for the given time step (dt).
save_state()	Saves the current state of the chassis, including CAD data, at the current simulation step.
set_velocity(vx, vy, vz, roll_rate, pitch_rate, yaw_rate)	Sets the chassis’s linear and angular velocities, including both translational and rotational components.
print_info()	Prints the current state of the chassis, including its position, orientation, velocity, and angular velocity.
update_chassis_data(kwargs)**	Updates chassis parameters dynamically based on the provided keyword arguments.
save_log_info(logger)	Logs the chassis parameters in a tabular format using the provided logger instance.

print_info()[source]#: Prints the current state of the chassis, including its position, orientation, velocity, and angular velocity.

save_log_info(logger)[source]#

Logs the chassis parameters in a tabular format using the provided logger instance.

Parameters:

loggerlogging.Logger: An instance of a logger object to record the chassis parameters.

save_state_2_text_file(output_file_path)[source]#

set_velocity(vx, vy, vz, roll_rate, pitch_rate, yaw_rate)[source]#

Sets the chassis’s linear and angular velocities, including both translational and rotational components.

Parameters:

vxfloat: The linear velocity along the x-axis.
vyfloat: The linear velocity along the y-axis.
vzfloat: The linear velocity along the z-axis.
roll_ratefloat: The angular velocity around the x-axis (roll).
pitch_ratefloat: The angular velocity around the y-axis (pitch).
yaw_ratefloat: The angular velocity around the z-axis (yaw).

update_chassis_data(**kwargs)[source]#

Updates chassis parameters dynamically based on the provided keyword arguments.

Parameters:

**kwargsdict: A dictionary of parameters to update in the chassis model.

update_state(dt)[source]#

Updates the chassis’s position and orientation based on the velocity and angular velocity for the given time step (dt).

Parameters:

dtfloat: The time step used for updating the chassis’s state.

Suspension#

Suspension Class#

The SimpleSuspension class represents the properties of a suspension system in a vehicle model. This class models the basic dynamics of the suspension, including the stiffness and damping characteristics.

class pymycar.Vehicle.suspension.SimpleSuspension(stiffness=None, damper=None)[source]#

Bases: object

Represents a simple suspension system with basic properties: stiffness and damping.

Attributes:

stiffnessfloat: The stiffness of the suspension in N/m. This value defines how much force the suspension applies to resist compression or extension.
damperfloat: The damping coefficient in Ns/m. This value defines the resistance the suspension provides against motion, simulating viscous friction.

Methods

__init__(stiffness, damper)	Initializes the suspension system with the specified stiffness and damping values.
save_log_info(logger, name=”Suspension”)	Logs the suspension parameters in a tabular format using the provided logger.

save_log_info(logger, name='Suspension')[source]#

Logs the suspension parameters in a tabular format using the provided logger.

Parameters:

loggerlogging.Logger: The logger instance that will be used to log the suspension details.
namestr, optional: Custom name for the suspension system (default: “Suspension”).

class pymycar.Vehicle.suspension.Suspension(kinematics)[source]#: Bases: object

Wheel#

Wheel Class#

The Wheel class represents the properties and dynamics of a single wheel in a vehicle model. This includes physical parameters such as mass, stiffness, and adherence properties, as well as the wheel’s position and orientation in 3D space.

class pymycar.Vehicle.wheel.Wheel(mass=None, spin_inertia=None, nominal_radius=None, radial_stiffness=None, radial_damping=None, nominal_vertical_load=None, max_longitudinal_adherence=None, max_lateral_adherence=None, sidelsip_stiffness=None, longitudinal_stiffness=None)[source]#

Bases: object

Represents a single wheel in the vehicle model with its physical and dynamic properties.

Attributes:

massfloat: Mass of the wheel in kilograms.
spin_inertiafloat: Moment of inertia for spinning motion in kg·m².
nominal_radiusfloat: Nominal radius of the wheel in meters.
radial_stiffnessfloat: Radial stiffness of the wheel in N/m.
radial_dampingfloat: Radial damping coefficient of the wheel in Ns/m.
nominal_vertical_loadfloat: Nominal vertical load supported by the wheel in N.
max_longitudinal_adherencefloat: Maximum longitudinal adherence coefficient.
max_lateral_adherencefloat: Maximum lateral adherence coefficient.
sidelsip_stiffnessfloat: Side-slip stiffness in N/deg.
longitudinal_stiffnessfloat: Longitudinal stiffness in N/deg.
xfloat: X-coordinate position of the wheel.
yfloat: Y-coordinate position of the wheel.
zfloat: Z-coordinate position of the wheel.
camberfloat: Camber angle of the wheel in degrees.
toefloat: Toe angle of the wheel in degrees.
side_viewfloat: Side view tilt angle of the wheel in degrees.

Methods

__init__(mass, spin_inertia, nominal_radius, radial_stiffness, radial_damping, nominal_vertical_load, max_longitudinal_adherence, max_lateral_adherence, sidelsip_stiffness, longitudinal_stiffness)	Initializes the Wheel object with provided or default parameters.
save_log_info(logger, name=”Wheel”)	Logs the wheel’s parameters in a tabular format.

save_log_info(logger, name='Wheel')[source]#

Logs the wheel parameters in a tabular format using the provided logger.

Parameters:

loggerlogging.Logger: Logger instance for logging the wheel details.
namestr, optional: Name or identifier for the wheel (default: “Wheel”).

save_state_2_text_file(output_file_path)[source]#