446 lines
16 KiB
Python
Executable File
446 lines
16 KiB
Python
Executable File
#!/usr/bin/env python2.7
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### Cesar Rodriguez July 2021
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### Based off of Klausen 2017 - Smooth trajectory generation based on desired waypoints
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import rospy, tf
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import numpy as np
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import time
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import math
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from pymavlink import mavutil
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from scipy import signal
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from scipy.integrate import odeint
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from oscillation_ctrl.msg import tethered_status, RefSignal
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from oscillation_ctrl.srv import WaypointTrack, WaypointTrackRequest
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from controller_msgs.msg import FlatTarget
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from geometry_msgs.msg import Pose, Vector3, PoseStamped, Point, TwistStamped
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from sensor_msgs.msg import Imu
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from mavros_msgs.msg import State
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class Main:
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def __init__(self):
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# rate(s)
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rate = 30 # rate for the publisher method, specified in Hz -- 10 Hz
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# initialize variables
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self.tstart = rospy.get_time() # Keep track of the start time
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while self.tstart == 0.0: # Need to make sure get_rostime works
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self.tstart = rospy.get_time()
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rospy.loginfo(self.tstart)
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self.dt = 1.0/rate
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# self.dt = 0.5
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# self.tmax = 100
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self.tmax = self.dt
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self.n = self.tmax/self.dt + 1
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self.t = np.linspace(0, self.tmax, self.n) # Time array
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# Message generation/ collection
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self.state = State()
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self.mode = ''
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self.vel_data = TwistStamped() # This is needed to get drone vel from gps
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self.imu_data = Imu() # Needed for to get drone acc from IMU
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self.ref_sig = FlatTarget() # Smooth Signal
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self.ref_sig.position.z = 5.0 # This does not need to be determined
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self.phi = 0.0 # Payload angle of deflection from x-axis
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self.phidot = 0.0
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self.theta = 0.0 # Payload angle of deflection from y-axis
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self.thetadot = 0.0
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self.has_run = 0 # Bool to keep track of first run instance
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self.drone_id = ''
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self.pload_id = ''
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self.pl_pos = Pose()
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self.dr_pos = Pose()
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self.dr_vel = self.vel_data.twist.linear
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self.dr_acc = self.imu_data.linear_acceleration
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self.dr_acc_p = self.imu_data.linear_acceleration
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# Get tether length
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self.param_exists = False
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while self.param_exists == False:
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if rospy.has_param('sim/tether_length'):
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self.tetherL = rospy.get_param('sim/tether_length') # Tether length
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self.param_exists = True
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elif rospy.get_time() - self.tstart >= 3.0:
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self.tetherL = 0.0
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break
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# --------------------------------------------------------------------------------#
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# SUBSCRIBERS #
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# --------------------------------------------------------------------------------#
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# Topic, msg type, and class callback method
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rospy.Subscriber('/status/twoBody_status', tethered_status, self.linkState_cb)
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rospy.Subscriber('/mavros/local_position/velocity_body', TwistStamped, self.droneVel_cb)
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rospy.Subscriber('/mavros/imu/data', Imu, self.droneAcc_cb)
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rospy.Subscriber('/mavros/state', State, self.state_cb)
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# --------------------------------------------------------------------------------#
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# PUBLISHERS
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# --------------------------------------------------------------------------------#
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# Publish desired path to compute attitudes
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self.pub_path = rospy.Publisher('/reference/path',FlatTarget,queue_size = 10)
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# Needed for geometric controller to compute thrust
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self.pub_ref = rospy.Publisher('/reference/flatsetpoint',FlatTarget,queue_size = 10)
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# timer(s), used to control method loop freq(s) as defined by the rate(s)
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self.pub_tim = rospy.Timer(rospy.Duration(1.0/rate), self.publisher)
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# --------------------------------------------------------------------------------#
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# FEEDBACK AND INPUT SHAPING
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# --------------------------------------------------------------------------------#
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# Smooth path variables
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self.EPS_F = np.zeros(9) # Final Epsilon/ signal
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self.EPS_I = np.zeros(9) # Epsilon shapefilter
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# Constants for smooth path generation
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self.w_tune = 3.13 # 3.13 works well? #########################################################################
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self.epsilon = 0.7 # Damping ratio
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# need exception if we do not have tether:
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if self.tetherL == 0.0:
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self.wn = self.w_tune
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else:
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self.wn = math.sqrt(9.81/self.tetherL)
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self.wd = self.wn*math.sqrt(1 - self.epsilon**2)
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self.k4 = 4*self.epsilon*self.w_tune
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self.k3 = ((2 + 4*self.epsilon**2)*self.w_tune**2)/self.k4
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self.k2 = (4*self.epsilon*self.w_tune**3)/(self.k4*self.k3)
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self.k1 = (self.w_tune**4)/(self.k2*self.k3*self.k4)
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# For saturation:
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self.jmax = [3, 3, 1]
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self.amax = [1.5, 1.5, 1]
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self.vmax = [3, 3, 1]
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self.max = [0, 3, 1.5, 3] #[0, 3, 1.5, 3]
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# create the array: [vmax; amax; jmax]
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self.max_array = np.array([[self.vmax],[self.amax],[self.jmax]]).T
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# Desired position array
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#if rospy.has_param('sim/waypoints'):
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# self.xd = rospy.get_param('sim/waypoints') # waypoints
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#elif rospy.get_time() - self.tstart >= 3.0:
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# self.xd = np.array([[0],[0],[5.0]]) # make our own if there are no waypoints
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#self.xd = Point()
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self.get_xd = rospy.ServiceProxy('/status/waypoint_tracker',WaypointTrack)
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self.empty_point = Point() # Needed to query waypoint_server
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self.des_waypoints = True # True = changing waypoints
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# Initial conditions: [pos, vel, acc, jerk]
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self.x0 = [0, 0, 0, 0]
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self.y0 = [0, 0, 0, 0]
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self.z0 = [0, 0, 0, 0]
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# Constants for feedback
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self.Gd = 0.325
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self.td = 2*self.Gd*math.pi/self.wd
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# Constants for shape filter/ Input shaping
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self.t1 = 0
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self.t2 = math.pi/self.wd
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self.K = math.exp(-self.epsilon*math.pi/math.sqrt(1 - self.epsilon**2))
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self.A1 = 1/(1 + self.K)
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self.A2 = self.A1*self.K
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# Need to determine how large of any array needs to be stored to use delayed functions
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self.SF_delay_x = np.zeros([4,int(round(self.t2/self.dt))]) # Shapefilter delay; 4 - p,v,a,j
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self.SF_delay_y = np.zeros([4,int(round(self.t2/self.dt))])
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self.phi_fb = np.zeros(int(round(self.td/self.dt))) # Feedback delay
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self.phi_vel_fb = np.zeros(int(round(self.td/self.dt)))
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self.phi_acc_fb = np.zeros(int(round(self.td/self.dt)))
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self.theta_fb = np.zeros(int(round(self.td/self.dt)))
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self.theta_vel_fb = np.zeros(int(round(self.td/self.dt)))
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self.theta_acc_fb = np.zeros(int(round(self.td/self.dt)))
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# Need index to keep track of path array of ^^^^ length
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self.SF_idx = 0
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self.FB_idx = 0
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# Constants for sigmoid
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self.at = 3 # acceleration theshold
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self.pc = 0.7 # From Klausen 2017
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self.sk = len(self.SF_delay_x[0]) # from Klausen 2017
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self.ak = np.zeros(len(self.SF_delay_x[0]))
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self.s_gain = 0.0 # Gain found from sigmoid
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# --------------------------------------------------------------------------------#
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# CALLBACK FUNCTIONS
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# --------------------------------------------------------------------------------#
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def state_cb(self, data):
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if self.state.armed != data.armed:
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rospy.loginfo("armed state changed from {0} to {1}".format(
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self.state.armed, data.armed))
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if self.state.connected != data.connected:
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rospy.loginfo("connected changed from {0} to {1}".format(
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self.state.connected, data.connected))
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if self.state.mode != data.mode:
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rospy.loginfo("mode changed from {0} to {1}".format(
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self.state.mode, data.mode))
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if self.state.system_status != data.system_status:
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rospy.loginfo("system_status changed from {0} to {1}".format(
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mavutil.mavlink.enums['MAV_STATE'][
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self.state.system_status].name, mavutil.mavlink.enums[
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'MAV_STATE'][data.system_status].name))
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self.state = data
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# mavros publishes a disconnected state message on init
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# Callback to get link names, states, and pload deflection angles
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def linkState_cb(self,msg):
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try:
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self.drone_id = msg.drone_id
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self.pload_id = msg.pload_id
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self.dr_pos = msg.drone_pos
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self.pl_pos = msg.pload_pos
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self.phi = -msg.phi
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self.phidot = -msg.phidot
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self.theta = msg.theta
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self.thetadot = msg.thetadot
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# self.tetherL = msg.length
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except ValueError:
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pass
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# Callback for drone velocity
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def droneVel_cb(self,msg):
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try:
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self.dr_vel = msg.twist.linear
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except ValueError or TypeError:
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pass
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# Callback for drone accel from IMU data
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def droneAcc_cb(self,msg):
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try:
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self.dr_acc = msg.linear_acceleration
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except ValueError:
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pass
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def waypoints_srv_cb(self):
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rospy.wait_for_service('/status/waypoint_tracker')
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try:
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resp = self.get_xd(False,self.empty_point)
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self.xd = resp.xd
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except ValueError:
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pass
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#################################################################
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#TODO Will need to add a function that gets a message from #
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# a node which lets refsignal_gen.py know there has been a #
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# change in xd and therefore runs waypoints_srv_cb again #
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#################################################################
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# --------------------------------------------------------------------------------#
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# ALGORITHM
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# --------------------------------------------------------------------------------#
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# --------------------------------------------------------------------------------#
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# TRAJECTORY GENERATION BASED ON WAYPONTS xd
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# --------------------------------------------------------------------------------#
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def statespace(self,y,t,xd):
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# Update initial conditions #
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# Need the statespace array:
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pos,vel,acc,jer = y
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# Derivative of statesape array:
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dydt = [vel, acc, jer,
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self.k4*(self.k3*(self.k2*(self.k1*(xd - pos) - vel) - acc) - jer)]
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return dydt
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# Sigmoid
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def sigmoid(self):
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for i in range(self.sk):
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if math.sqrt(self.SF_delay_x[2,i]**2 + self.SF_delay_y[2,i]**2) < self.at:
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self.ak[i] = 1
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else:
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self.ak[i] = 0
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pk = sum(self.ak)/self.sk
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self.s_gain = 1/(1 + math.exp(-self.sk*(pk-self.pc)))
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def delay(self,j,cmd):
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'''
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Function to keep track of values in past. Needed for
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Shape filtering as well as feedback
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j -> tells if we are doing pos, vel, or acc
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cmd -> determines SF or FB
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'''
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if cmd == 1: # Shape filter
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if self.SF_idx < len(self.SF_delay_x[0]):
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# First, fill up the delay array
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self.SF_delay_x[j,self.SF_idx] = self.x[1,j]
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self.SF_delay_y[j,self.SF_idx] = self.y[1,j]
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else:
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# once array is filled, we start using the first value every time
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# x
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self.SF_delay_x[j,:] = np.roll(self.SF_delay_x[j,:],-1) # makes the first value last
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self.SF_delay_x[j,len(self.SF_delay_x[0])-1] = self.x[1,j] # updates last value to current x
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# y
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self.SF_delay_y[j,:] = np.roll(self.SF_delay_y[j,:],-1)
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self.SF_delay_y[j,len(self.SF_delay_y[0])-1] = self.y[1,j]
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elif cmd == 2: # Feedback
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if self.FB_idx < len(self.theta_fb):
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# First, fill up the delay array
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self.theta_fb[self.FB_idx] = self.theta
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self.theta_vel_fb[self.FB_idx] = self.thetadot
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self.theta_acc_fb[self.FB_idx] = self.thetadot - self.theta_vel_fb[self.FB_idx-1]
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self.phi_fb[self.FB_idx] = self.phi
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self.phi_vel_fb[self.FB_idx] = self.phidot
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self.phi_acc_fb[self.FB_idx] = self.phidot - self.phi_vel_fb[self.FB_idx-1]
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else:
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# once array is filled, need to shift values w/ latest value at end
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self.theta_fb[:] = np.roll(self.theta_fb[:],-1)
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self.theta_vel_fb[:] = np.roll(self.theta_vel_fb[:],-1)
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self.theta_acc_fb[:] = np.roll(self.theta_acc_fb[:],-1)
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self.phi_fb[:] = np.roll(self.phi_fb[:],-1)
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self.phi_vel_fb[:] = np.roll(self.phi_vel_fb[:],-1)
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self.phi_acc_fb[:] = np.roll(self.phi_acc_fb[:],-1)
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self.theta_fb[len(self.theta_fb)-1] = self.theta # change final value
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self.theta_vel_fb[len(self.theta_fb)-1] = self.thetadot
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self.theta_acc_fb[len(self.theta_fb)-1] = self.thetadot - self.theta_vel_fb[len(self.theta_fb)-1]
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self.phi_fb[len(self.phi_fb)-1] = self.phi
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self.phi_vel_fb[len(self.theta_fb)-1] = self.phidot
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self.phi_acc_fb[len(self.theta_fb)-1] = self.phidot - self.phi_vel_fb[len(self.theta_fb)-1]
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else:
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print('No delay')
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# Convolution of shape filter and trajectory, and feedback
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def convo(self):
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self.waypoints_srv_cb()
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# needed for delay function
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# 1 = determine shapefilter array
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# 2 = determine theta/phi_fb
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shapeFil = 1
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feedBack = 2
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# SOLVE ODE (get ref pos, vel, accel)
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self.x = odeint(self.statespace,self.x0,self.t,args=(self.xd.x,))
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self.y = odeint(self.statespace,self.y0,self.t,args=(self.xd.y,))
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self.z = odeint(self.statespace,self.z0,self.t,args=(self.xd.z,))
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for i in range(1,len(self.y0)):
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self.x[:,i] = np.clip(self.x[:,i], a_min = -self.max[i], a_max = self.max[i])
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self.y[:,i] = np.clip(self.y[:,i], a_min = -self.max[i], a_max = self.max[i])
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self.z[:,i] = np.clip(self.z[:,i], a_min = -self.max[i], a_max = self.max[i])
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for j in range(3): # 3 is due to pos, vel, acc. NOT due x, y, z
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self.delay(j,shapeFil) # Determine the delay (shapefilter) array
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if self.SF_idx < len(self.SF_delay_x[0]):
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self.EPS_I[3*j] = self.x[1,j]
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self.EPS_I[3*j+1] = self.y[1,j]
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self.EPS_I[3*j+2] = self.z[1,j]
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else:
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self.EPS_I[3*j] = self.A1*self.x[1,j] + self.A2*self.SF_delay_x[j,0] # Determine convolution (x)
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self.EPS_I[3*j+1] = self.A1*self.y[1,j] + self.A2*self.SF_delay_y[j,0] # Determine convolution (y)
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self.EPS_I[3*j+2] = self.z[1,j] # No need to convolute z-dim
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self.delay(1,feedBack) # Detemine feedback array
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self.sigmoid() # Determine sigmoid gain
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EPS_D = self.fback() # Feedback Epsilon
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for i in range(9):
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# Populate EPS_F buffer with desired change based on feedback
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self.EPS_F[i] = self.EPS_I[i] + EPS_D[i] #+ EPS_D[i]
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# Populate msg with epsilon_final
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self.ref_sig.header.stamp = rospy.Time.now()
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self.ref_sig.type_mask = 2 # Need typemask = 2 to use correct attitude controller - Jaeyoung Lin
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self.ref_sig.position.x = self.EPS_F[0]
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self.ref_sig.position.y = self.EPS_F[1]
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self.ref_sig.position.z = self.EPS_F[2] + 0.5
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self.ref_sig.velocity.x = self.EPS_F[3]
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self.ref_sig.velocity.y = self.EPS_F[4]
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self.ref_sig.velocity.z = self.EPS_F[5]
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self.ref_sig.acceleration.x = self.EPS_F[6]
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self.ref_sig.acceleration.y = self.EPS_F[7]
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self.ref_sig.acceleration.z = self.EPS_F[8]
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self.x0 = [self.dr_pos.position.x, self.x[1,1], self.x[1,2], self.x[1,3]]
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self.y0 = [self.dr_pos.position.y, self.y[1,1], self.y[1,2], self.y[1,3]]
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self.z0 = [self.dr_pos.position.z, self.z[1,1], self.z[1,2], self.z[1,3]]
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self.SF_idx += 1
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self.FB_idx += 1
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def fback(self):
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xr = self.Gd*self.tetherL*math.sin(self.theta_fb[0])
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xdotr = self.Gd*self.tetherL*math.cos(self.theta_fb[0])*self.theta_vel_fb[0]
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xddotr = -self.Gd*self.tetherL*math.sin(self.theta_fb[0])*(self.theta_vel_fb[0]**2) + math.cos(self.theta_fb[0])*self.theta_acc_fb[0]
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yr = -self.Gd*self.tetherL*math.sin(self.phi_fb[0])
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ydotr = -self.Gd*self.tetherL*math.cos(self.phi_fb[0])*self.phi_vel_fb[0]
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yddotr = self.Gd*self.tetherL*math.sin(self.phi_fb[0])*self.phi_vel_fb[0]**2 + math.cos(self.phi_fb[0])*self.phi_acc_fb[0]
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EPS_D = np.array([xr,yr,0,xdotr,ydotr,0,xddotr,yddotr,0])
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return EPS_D
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def screen_output(self):
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# Feedback to user
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rospy.loginfo(' Var | x | y | z ')
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rospy.loginfo('Pos: %.2f %.2f %.2f',self.EPS_F[0],self.EPS_F[1],self.EPS_F[2])
|
|
rospy.loginfo('Vel: %.2f %.2f %.2f',self.EPS_F[3],self.EPS_F[4],self.EPS_F[5])
|
|
rospy.loginfo('Acc: %.2f %.2f %.2f',self.EPS_F[6],self.EPS_F[7],self.EPS_F[8])
|
|
rospy.loginfo('_______________________')
|
|
|
|
def publisher(self,pub_tim):
|
|
|
|
# Determine final ref signal
|
|
self.convo()
|
|
|
|
# Publish reference signal
|
|
self.pub_path.publish(self.ref_sig)
|
|
self.pub_ref.publish(self.ref_sig)
|
|
|
|
# Give user feedback on published message:
|
|
rospy.loginfo(' Var | x | y | z ')
|
|
rospy.loginfo('Pos: %.2f %.2f %.2f',self.EPS_F[0],self.EPS_F[1],self.EPS_F[2])
|
|
rospy.loginfo('Vel: %.2f %.2f %.2f',self.EPS_F[3],self.EPS_F[4],self.EPS_F[5])
|
|
rospy.loginfo('Acc: %.2f %.2f %.2f',self.EPS_F[6],self.EPS_F[7],self.EPS_F[8])
|
|
rospy.loginfo('_______________________')
|
|
|
|
|
|
if __name__=="__main__":
|
|
|
|
# Initiate ROS node
|
|
rospy.init_node('desPath_node',anonymous=True)
|
|
try:
|
|
Main() # create class object
|
|
rospy.spin() # loop until shutdown signal
|
|
|
|
except rospy.ROSInterruptException:
|
|
pass
|
|
|