Source code for morse.core.wheeled_robot

import logging; logger = logging.getLogger("morse." + __name__)
from abc import ABCMeta
import morse.core.robot
from morse.core import blenderapi
import mathutils

[docs]class PhysicsWheelRobotClass(morse.core.robot.Robot): """ Abstract base class for robots with wheels that turn as the robot moves. The wheels must be children of the robot in the Blender file. """ # Make this an abstract class __metaclass__ = ABCMeta # Local dictionaries to store references to the wheels _wheel_index = ['FL', 'FR', 'RL', 'RR'] _wheels = {} _wheel_positions = {} _wheel_orientations = {} _wheel_joints = {}
[docs] def action(self): """ Overload the 'action' method of the Robot This one will compute the transformations considering the different axis orientation used by this kind of robots """ # Update the component's position in the world self.position_3d.update_Y_forward(self.bge_object) self.default_action()
[docs] def GetWheels(self): # get pointers to and physicsIds of all objects # get wheel pointers - needed by wheel speed sensors and to # set up constraints # bullet vehicles always have 4 wheels scene=blenderapi.scene() # inherited from the parent robot for index in self._wheel_index: name = "Wheel%sName" % index # Get the actual name of the object from the properties # of the parent robot try: wheel = scene.objects[self.bge_object[name]] except: #import traceback #traceback.print_exc() wheel = None if wheel: self._wheels[index] = wheel logger.info("\tWheel %s: %s" % (index, wheel.name)) self._wheel_positions[index] = mathutils.Vector(wheel.worldPosition) self._wheel_orientations[index] = mathutils.Matrix(wheel.worldOrientation) # Make the wheels orphans wheel.removeParent() # Keep their transformations #wheel.worldPosition = self._wheel_positions[index] #wheel.worldOrientation = self._wheel_orientations[index] logger.debug("GetWheels %s" % self._wheels) # get wheel radius self._wheelRadius=self.GetWheelRadius(self.bge_object['WheelFLName']) # Add a free rotating wheel if indicated in the robot if 'CasterWheelName' in self.bge_object: wheel = scene.objects[self.bge_object['CasterWheelName']] wheel_position = mathutils.Vector(wheel.worldPosition) self.AttachCasterWheelToBody(wheel, self.bge_object, wheel_position)
[docs] def ReadGenericParameters(self): # get needed parameters from the blender object # determines if vehicle has suspension or just wheels try: self._HasSuspension=self.bge_object['HasSuspension'] except KeyError as e: self._HasSuspension=True logger.info('HasSuspension property not present and defaulted to True') except: import traceback traceback.print_exc() # determines if vehicle has steerable front wheels or not try: self._HasSteering=self.bge_object['HasSteering'] except KeyError as e: self._HasSteering=True logger.info('HasSteering property not present and defaulted to True') except: import traceback traceback.print_exc()
[docs] def GetTrackWidth(self): # get lateral positions of the wheels posL = self._wheel_positions['FL'] posR = self._wheel_positions['FR'] # subtract y coordinates of wheels to get width return posL[1]-posR[1]
[docs] def GetWheelRadius(self, wheelName): dims=blenderapi.objectdata(wheelName).dimensions # average the x and y dimension to get diameter - divide by 2 for radius return (dims[0]+dims[1])/4
[docs]class MorsePhysicsRobotClass(PhysicsWheelRobotClass): """ Basic Class for robots using individual physics constraints Inherits from the base robot class. """ def __init__ (self, obj, parent=None): """ Constructor method. """ # Call the constructor of the parent class super(MorsePhysicsRobotClass, self).__init__(obj, parent) # get wheel references and ID's self.GetWheels() # construct the vehicle self.build_vehicle()
[docs] def build_vehicle(self): """ Apply the constraints to the vehicle parts. """ # get a link to the blender scene to look for wheel and suspension objectsscene = blenderapi.scene() # get needed parameters from the blender object self.ReadGenericParameters() # chassis ID - main object should be chassis model self._chassis_ID = self.bge_object.getPhysicsId() # get track width self._trackWidth=self.GetTrackWidth(); # set up wheel constraints # add wheels to either suspension arms or vehicle chassis if (self._HasSuspension): self.BuildModelWithSuspension() else: self.BuildModelWithoutSuspension() # def BuildModelWithSuspension(self): # """ Add all the constraints to attach the wheels to # the a-arms and then the a-arms to the body """ # scene = blenderapi.scene() # # get suspension arm ID's # # front left A-arm # try: # if self.bge_object['ArmFLName']: # self._armFL=scene.objects[self.bge_object['ArmFLName']] # except: # import traceback # traceback.print_exc() # # # front right A-arm # try: # if self.bge_object['ArmFRName']: # self._armFR=scene.objects[self.bge_object['ArmFRName']] # except: # import traceback # traceback.print_exc() # # # rear left arm # try: # if self.bge_object['ArmRLName']: # self._armRL=self.bge_object['ArmRLName'] # except: # import traceback # traceback.print_exc() # # # rear right arm # try: # if self.bge_object['ArmRRName']: # self._armRR=self.bge_object['ArmRRName'] # except: # import traceback # traceback.print_exc() # # # put together front wheels and suspension # self._wheelFLJoint=self.AttachWheelWithSuspension(self._wheelFL,self.bge_object,self._armFL) # self._wheelFRJoint=self.AttachWheelWithSuspension(self._wheelFR,self.bge_object,self._armFR) # # self._wheelRLJoint=self.AttachWheelWithSuspension(self._wheelRL,self.bge_object,self._armRL) # self._wheelRRJoint=self.AttachWheelWithSuspension(self._wheelRR,self.bge_object,self._armRR)
[docs] def BuildModelWithoutSuspension(self): """ Add all the constraints to attach the wheels to the body """ for index in self._wheels.keys(): self._wheel_joints[index] = self.AttachWheelToBody(self._wheels[index], self.bge_object, self._wheel_positions[index])
[docs] def AttachWheelToBody(self, wheel, parent, wheelPos): """ Attaches the wheel to the given parent using a 6DOF constraint """ # set the wheel positions relative to the robot in case the # chassis was moved by the builder script or manually in blender """ globalWheelPos=wheelPos+parent.worldPosition wheel.worldPosition=globalWheelPos """ result = parent.getVectTo(wheel); ## result is a unit vector (result[2]) and a length(result[0]) ## multiply them together to get the complete vector wheelPos=result[0]*result[2] logger.debug("Added wheel '%s' at ('%f','%f','%f')" %(wheel.name, wheelPos[0], wheelPos[1], wheelPos[2])) # create constraint to allow wheel to spin # For an explanation on the parameters, see: # http://www.tutorialsforblender3d.com/GameModule/ClassKX_PyConstraintBinding_1f.html joint = blenderapi.constraints().createConstraint( parent.getPhysicsId(), # get physics ID of the parent object wheel.getPhysicsId(), # get physics ID of the wheel object 12, # 6dof constraint wheelPos[0], wheelPos[1], wheelPos[2], # pivot position 0,0,0, # pivot axis 128) # flag, 128=disable collision between wheel and parent # no parameters are set on x axis to allow full rotation about it joint.setParam(4,0.0,0.0) # no rotation about Y axis - min=0, max=0 joint.setParam(5,0.0,0.0) # no rotation about Z axis - min=0, max=0 return joint # return a reference to the constraint
[docs] def AttachCasterWheelToBody(self, wheel, parent, wheelPos): """ Attaches a freely rotating wheel to the given parent using a 6DOF constraint. It can also rotate around the Z axis """ result = parent.getVectTo(wheel); ## result is a unit vector (result[2]) and a length(result[0]) ## multiply them together to get the complete vector wheelPos=result[0]*result[2] logger.debug("Added caster wheel '%s' at ('%f','%f','%f')" %(wheel.name, wheelPos[0], wheelPos[1], wheelPos[2])) # create constraint to allow wheel to spin joint = blenderapi.constraints().createConstraint( parent.getPhysicsId(), # get physics ID of the parent object wheel.getPhysicsId(), # get physics ID of the wheel object 12, # 6dof constraint wheelPos[0], wheelPos[1], wheelPos[2], # pivot position 0,0,0, # pivot axis 128) # flag, 128=disable collision between wheel and parent # no parameters are set on x and z axis to allow full rotation about it joint.setParam(4,0.0,0.0) # no rotation about Y axis - min=0, max=0 joint.setParam(5,0.0,0.0) # no rotation about Z axis - min=0, max=0 return joint # return a reference to the constraint
[docs] def AttachWheelWithSuspension(self, wheel, parent, suspensionArm): """ Attaches the wheel to the a-arm and then the a-arm to the body """ # TODO: fill this in later - model after Bueraki code pass # def getWheelSpeeds(self): # """ Returns the angular wheel velocity in rad/sec""" # # true parameters tell it velocities are local # # wheels should be rotating about local Z axis # wsFL=self._wheelFL.getAngularVelocity(True) # wsFR=self._wheelFR.getAngularVelocity(True) # wsRL=self._wheelRL.getAngularVelocity(True) # wsRR=self._wheelRR.getAngularVelocity(True) # return [wsFL[2], wsFR[2], wsRL[2], wsRR[2]] # # def getWheelAngle(self): # """ Returns the accumulated wheel angle in radians""" # # true parameters tell it velocities are local # # wheels should be rotating about local Z axis # wcFL=self._wheelFL.localOrientation.to_euler() # wcFR=self._wheelFR.localOrientation.to_euler() # wcRL=self._wheelRL.localOrientation.to_euler() # wcRR=self._wheelRR.localOrientation.to_euler() # return [wcFL[1], wcFR[1], wcRL[1], wcRR[1]] # # def AttachWheelToWheel(self,wheel1,wheel2): # # add both wheels on each side to each other but with no # # constraints on their motion so that no collision can be set # # between them # pass