class TomIMU: def __init__(self,host,port,uid,callbackPeriodMS=100): self.host=host self.port=port self.uid=uid self._imu = IMU(uid) # Create device object self._ipcon = IPConnection(self.host,self.port) # Create IPconnection to brickd self._ipcon.add_device(self._imu) # Add device to IP connection self.ready = True # Don't use device before it is added to a connection # Set period for quaternion callback (defaults to 100ms) self._imu.set_quaternion_period(callbackPeriodMS) # Register quaternion callback self._imu.register_callback(self._imu.CALLBACK_QUATERNION, self._QuaternionCallback) self._imu.leds_off() # Turn LEDs off. self._imu.set_convergence_speed(5) # 5ms convergence. # Orientation origin and most recent values q = self._imu.get_quaternion() # Get a temp quaternion from current pose. self.rel_x = q.x self.rel_y = q.y self.rel_z = q.z self.rel_w = q.w self.x = q.x self.y = q.y self.z = q.z self.w = q.w def __destroy__(self): self._ipcon.destroy() def _QuaternionCallback(self, x, y, z, w): """ Records the most recent quaternion orientation values. """ self.x,self.y,self.z,self.w = x,y,z,w def SetOrientationOrigin(self, origin=None): """ Resets the orientation origin to the given values, or the latest reading if none. """ if origin is None: self.rel_x, self.rel_y, self.rel_z, self.rel_w = self.x, self.y, self.z, self.w else: self.rel_x, self.rel_y, self.rel_z, self.rel_w = origin def GetEulerOrientation(self): x,y,z,w = self.GetQuaternionOrientation() from math import atan2, asin roll = atan2(2.0*y*w - 2.0*x*z, 1.0 - 2.0*y*y - 2.0*z*z) pitch = atan2(2.0*x*w - 2.0*y*z, 1.0 - 2.0*x*x - 2.0*z*z) yaw = asin(2.0*x*y + 2.0*z*w) return roll,pitch,yaw def GetQuaternionOrientation(self): # Conjugate x,y,z = -self.x, -self.y, -self.z w = self.w # Multiply wn = w * self.rel_w - x * self.rel_x - y * self.rel_y - z * self.rel_z xn = w * self.rel_x + x * self.rel_w + y * self.rel_z - z * self.rel_y yn = w * self.rel_y - x * self.rel_z + y * self.rel_w + z * self.rel_x zn = w * self.rel_z + x * self.rel_y - y * self.rel_x + z * self.rel_w return xn,yn,zn,wn def GetConvergenceSpeed(self): return self._imu.get_convergence_speed() def SetConvergenceSpeed(self, speed): self._imu.set_convergence_speed(speed)
