Source code for morse.actuators.drag

import logging; logger = logging.getLogger("morse." + __name__)
import morse.core.actuator
from morse.core.mathutils import Vector
from morse.helpers.components import add_property
from math import copysign

[docs]class Drag(morse.core.actuator.Actuator): """ This actuator allows to simulate the drag force, or fluid resistance. It is not controlable, as it depends only of robot parameters, and environment. The drag force is generally written as: Fd = 0.5 * rho * vel_sq * A * Cd where - rho is the density of the fluid (env dependant) - A is the cross sectional area (robot dependent) - Cd is the drag coefficient, related to the object shape and the Reynolds Number All these values are aggregated into the property DragCoeff, to ease the configuration of the component. """ _name = "Drag" _short_desc = "Actuator allowing to simulate the drag force" add_property('_drag_coeff_x', 0.09, 'DragCoeffX', 'float' 'An aggregated value to scale the drag force on X robot axis') add_property('_drag_coeff_y', 0.09, 'DragCoeffY', 'float' 'An aggregated value to scale the drag force on Y robot axis') add_property('_drag_coeff_z', 0.5, 'DragCoeffZ', 'float' 'An aggregated value to scale the drag force on Z robot axis') def __init__(self, obj, parent=None):'%s initialization' % # Call the constructor of the parent class morse.core.actuator.Actuator.__init__(self, obj, parent) # Make new reference to the robot velocities (mathutils.Vector) self.robot_vel = self.robot_parent.bge_object.localLinearVelocity self._drag_coeff = [self._drag_coeff_x, self._drag_coeff_y, self._drag_coeff_z]"Component initialized, runs at %.2f Hz ", self.frequency)
[docs] def default_action(self): robot = self.robot_parent drag = Vector((0.0, 0.0, 0.0)) for i in range(3): v = self.robot_vel[i] drag[i] = - copysign(1.0, v) * v * v * self._drag_coeff[i] logger.debug("Drag force %s" % drag) robot.bge_object.applyForce(drag, True)