hks_teleop.py

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#!/usr/bin/python
#
#  send Ackermann tele-operation commands from an HKS racing controller
#
#   Copyright (C) 2011 Jack O'Quin, Joshua Bennett
#   Copyright (C) 2012 Jack O'Quin
#   License: Modified BSD Software License Agreement
#
# $Id: joy_teleop.py 1321 2011-04-19 20:23:37Z jack.oquin $

PKG_NAME = 'ackermann_hks'

# standard Python packages
import sys
import math
import Queue

import pilot_cmd                # ART pilot interface

# ROS node setup
import roslib;
roslib.load_manifest(PKG_NAME)
import rospy

# ROS messages
from art_msgs.msg import Gear
from sensor_msgs.msg import Joy

# dynamic parameter reconfiguration
from driver_base.msg import SensorLevels
from dynamic_reconfigure.server import Server as ReconfigureServer
import ackermann_hks.cfg.HKSConfig as Config

def clamp(minimum, value, maximum):
    "constrain value to the range [minimum .. maximum]"
    return max(minimum, min(value, maximum))

class JoyNode():
    "Vehicle joystick tele-operation node."

    def __init__(self):
        "JoyNode constructor"

        # estop control
        self.estop = 13                 # emergency stop

        # tele-operation controls
        self.steer = 0                  # steering axis (wheel)
        self.drive = 4                  # shift to Drive (^)
        self.reverse = 6                # shift to Reverse (v)
        self.park = 7                   # shift to Park
        self.throttle = 18              # throttle axis (X)
        self.throttle_start = True
        self.brake = 19                 # brake axis (square)
        self.brake_start = True
        self.counter = 0
        self.throttleQueue = Queue.Queue()
        self.cruiseSwitch = 1           # Press down Joystick
        self.cruise = False
        
        # initialize ROS topics
        rospy.init_node('hks_teleop')
        self.pilot = pilot_cmd.PilotCommand()
        self.reconf_server = ReconfigureServer(Config, self.reconfigure)
        self.joy = rospy.Subscriber('joy', Joy, self.joyCallback)


    def joyCallback(self, joy):
        "invoked every time a joystick message arrives"
        rospy.logdebug('joystick input:\n' + str(joy))

        # handle E-stop button
        if joy.buttons[self.estop]:
            rospy.logwarn('emergency stop')
            self.pilot.halt()           # halt car using pilot

        # handle shifter buttons
        if joy.buttons[self.drive]:
            self.pilot.shift(Gear.Drive)
            rospy.loginfo('shifting to drive')
        elif joy.buttons[self.reverse]:
            self.pilot.shift(Gear.Reverse)
            rospy.loginfo('shifting to reverse')
        elif joy.buttons[self.park]:
            self.pilot.shift(Gear.Park)
            rospy.loginfo('shifting to park')

        if joy.buttons[self.cruiseSwitch]:
            if self.cruise:
                self.cruise = False
            else:
                self.cruise = True
                self.pilot.pstate.target.speed = self.pilot.pstate.current.speed

        # set steering angle
        self.setAngle(joy.axes[self.steer])

        if self.cruise:
                self.pilot.accelerate(0)

        else:
                # adjust speed -- the brake and throttle controls both
                # return 1.0 when released, -1.0 when completely on
                # Convert the -1 to 1 to 0 to 1 in increments of .01
                br = (-joy.axes[self.brake] + 1) / 2
                th = (-joy.axes[self.throttle] + 1) / 2
                rospy.logdebug('joystick brake, throttle: '
                               + str(br) + ', ' + str(th))

                if self.counter < 1:
                        self.counter = 1
                        self.throttleQueue.put(th)
                else:
                        initial_th = self.throttleQueue.get()
                        self.throttleQueue.put(th)

                # initially the ROS /joy topic sends zeroes for each axis
                # until a button press occurs
        
        
                if self.brake_start:
                    if br == 0.5:
                        br = 0
                    else:
                        self.brake_start = False

                if self.throttle_start:
                    if th == 0.5:
                        th = 0
                    else:
                        self.throttle_start = False

                # set dv according to throttle or brake's current state.
                if br > 0:
                        dv = -br * 3

                elif th == 0 and self.pilot.pstate.current.speed > 0:
                        dv = -.1

                elif th > 0:
                        if initial_th < th:
                                dv = th
                        elif initial_th > th:
                                dv = -.1 
                        elif initial_th == th and self.pilot.pstate.current.acceleration >= 0:
                                dv = th
                        elif initial_th == th and self.pilot.pstate.current.acceleration < 0:
                                dv = -.1
                        else:
                                dv = 0
                else:
                        dv = 0

                # set acceleration and speed from brake and throttle controls
                self.pilot.accelerate(dv*10)

        if self.nav.is_suspended(): # OK to issue command?
            self.pilot.publish()
        else:
            rospy.logdebug('car running autonomously (command ignored)')

    def reconfigure(self, config, level):
        "Dynamic reconfigure server callback."
        rospy.loginfo('Reconfigure callback, level ' + str(level))
        rospy.loginfo('New config ' + str(config))
        self.pilot.reconfigure(config['limit_forward'],
                               config['limit_reverse'])
        self.config = config
        return config

    def setAngle(self, turn):
        "set wheel angle"

        # Try various functions with domain [-1..1] to improve
        # sensitivity while retaining sign. At higher speeds, it may
        # make sense to limit the range, avoiding too-sharp turns and
        # providing better control sensitivity.
        #turn = math.pow(turn, 3) * self.config.max_steering
        #turn = math.tan(turn) * self.config.max_steering
        if self.pilot.pstate.current.speed == 0:
                percentage = 1
        # Expirimental steering over speed preference
        #if self.pilot.pstate.current.speed <= 5:
        #       percentage = 1
        
        else:
                #percentage = -0.2738*(math.log(math.fabs(self.pilot.pstate.current.speed))) + 0.6937
                percentage = (-math.atan2(math.fabs(self.pilot.pstate.current.speed)-3, 1) / 1.5) + 1
        turn = turn * percentage * self.config.max_steering

        # ensure maximum wheel angle never exceeded
        self.pilot.steer(turn)

        def maxFinder(self):
                if self.pilot.pstate.current.speed > self.config['limit_forward']:
                        return self.pilot.state.current
                return self.config['limit_forward']

joynode = None


def main():
    global joynode
    joynode = JoyNode()
    rospy.loginfo('joystick vehicle controller starting')
    try:
        rospy.spin()
    except rospy.ROSInterruptException: pass
    rospy.loginfo('joystick vehicle controller finished')

if __name__ == '__main__':
    # run main function and exit
    sys.exit(main())