使用PX4和mavros编写无人机在各种模式下的例程代码，如offboard、mission、takeoff、land、return、hold等模式

以下是使用PX4和mavros编写无人机在各种模式下的例程代码：

1. Offboard模式：

import rospy
from mavros_msgs.msg import *
from mavros_msgs.srv import *

def set_mode(mode):
    rospy.wait_for_service('/mavros/set_mode')
    try:
        flight_mode = rospy.ServiceProxy('/mavros/set_mode', SetMode)
        flight_mode(custom_mode=mode)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_offboard_mode():
    set_mode("OFFBOARD")

def set_arm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(True)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_disarm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(False)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_attitude(roll, pitch, yaw, thrust):
    rospy.wait_for_service('/mavros/cmd/command')
    try:
        set_att = rospy.ServiceProxy('/mavros/cmd/command', CommandLong)
        set_att(0, 0, 186, 0, 0, 0, roll, pitch, yaw, thrust)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def offboard():
    rospy.init_node('offboard_node', anonymous=True)
    rate = rospy.Rate(20)
    set_offboard_mode()
    set_arm()

    while not rospy.is_shutdown():
        set_attitude(0, 0, 0, 0.5)
        rate.sleep()

    set_disarm()

2. Mission模式：

import rospy
from mavros_msgs.msg import *
from mavros_msgs.srv import *

def set_mode(mode):
    rospy.wait_for_service('/mavros/set_mode')
    try:
        flight_mode = rospy.ServiceProxy('/mavros/set_mode', SetMode)
        flight_mode(custom_mode=mode)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_arm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(True)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_disarm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(False)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_waypoint(x, y, z):
    rospy.wait_for_service('/mavros/cmd/mission/push')
    try:
        set_wp = rospy.ServiceProxy('/mavros/cmd/mission/push', WaypointPush)
        wp = Waypoint()
        wp.frame = 3
        wp.command = 16
        wp.is_current = False
        wp.autocontinue = True
        wp.param1 = 0
        wp.param2 = 0
        wp.param3 = 0
        wp.param4 = 0
        wp.x_lat = x
        wp.y_long = y
        wp.z_alt = z
        set_wp(start_index=0, waypoints=[wp])
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_mission_mode():
    set_mode("AUTO.MISSION")

def mission():
    rospy.init_node('mission_node', anonymous=True)
    rate = rospy.Rate(20)
    set_arm()
    set_waypoint(0, 0, 5)
    set_waypoint(10, 0, 5)
    set_waypoint(10, 10, 5)
    set_waypoint(0, 10, 5)
    set_waypoint(0, 0, 5)
    set_mission_mode()

    while not rospy.is_shutdown():
        rate.sleep()

    set_disarm()

3. Takeoff模式：

import rospy
from mavros_msgs.msg import *
from mavros_msgs.srv import *

def set_mode(mode):
    rospy.wait_for_service('/mavros/set_mode')
    try:
        flight_mode = rospy.ServiceProxy('/mavros/set_mode', SetMode)
        flight_mode(custom_mode=mode)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_arm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(True)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_disarm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(False)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_takeoff_altitude(altitude):
    rospy.wait_for_service('/mavros/cmd/takeoff')
    try:
        takeoff = rospy.ServiceProxy('/mavros/cmd/takeoff', CommandTOL)
        takeoff(min_pitch=0, yaw=0, latitude=0, longitude=0, altitude=altitude)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def takeoff():
    rospy.init_node('takeoff_node', anonymous=True)
    rate = rospy.Rate(20)
    set_arm()
    set_takeoff_altitude(5)
    set_mode("AUTO.TAKEOFF")

    while not rospy.is_shutdown():
        rate.sleep()

    set_disarm()

4. Land模式：

import rospy
from mavros_msgs.msg import *
from mavros_msgs.srv import *

def set_mode(mode):
    rospy.wait_for_service('/mavros/set_mode')
    try:
        flight_mode = rospy.ServiceProxy('/mavros/set_mode', SetMode)
        flight_mode(custom_mode=mode)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_arm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(True)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_disarm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(False)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_land():
    rospy.wait_for_service('/mavros/cmd/land')
    try:
        land = rospy.ServiceProxy('/mavros/cmd/land', CommandTOL)
        land(min_pitch=0, yaw=0, latitude=0, longitude=0, altitude=0)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def land():
    rospy.init_node('land_node', anonymous=True)
    rate = rospy.Rate(20)
    set_arm()
    set_mode("AUTO.LAND")
    set_land()

    while not rospy.is_shutdown():
        rate.sleep()

    set_disarm()

5. Return模式：

import rospy
from mavros_msgs.msg import *
from mavros_msgs.srv import *

def set_mode(mode):
    rospy.wait_for_service('/mavros/set_mode')
    try:
        flight_mode = rospy.ServiceProxy('/mavros/set_mode', SetMode)
        flight_mode(custom_mode=mode)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_arm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(True)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_disarm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(False)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_return():
    rospy.wait_for_service('/mavros/cmd/rtl')
    try:
        rtl = rospy.ServiceProxy('/mavros/cmd/rtl', CommandTOL)
        rtl(min_pitch=0, yaw=0, latitude=0, longitude=0, altitude=0)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def return_home():
    rospy.init_node('return_node', anonymous=True)
    rate = rospy.Rate(20)
    set_arm()
    set_mode("AUTO.RTL")
    set_return()

    while not rospy.is_shutdown():
        rate.sleep()

    set_disarm()

6. Hold模式：

import rospy
from mavros_msgs.msg import *
from mavros_msgs.srv import *

def set_mode(mode):
    rospy.wait_for_service('/mavros/set_mode')
    try:
        flight_mode = rospy.ServiceProxy('/mavros/set_mode', SetMode)
        flight_mode(custom_mode=mode)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_arm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(True)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_disarm():
    rospy.wait_for_service('/mavros/cmd/arming')
    try:
        arm = rospy.ServiceProxy('/mavros/cmd/arming', CommandBool)
        arm(False)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def set_hold():
    rospy.wait_for_service('/mavros/cmd/command')
    try:
        set_att = rospy.ServiceProxy('/mavros/cmd/command', CommandLong)
        set_att(0, 0, 186, 0, 0, 0, 0, 0, 0, 0)
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

def hold():
    rospy.init_node('hold_node', anonymous=True)
    rate = rospy.Rate(20)
    set_arm()
    set_mode("AUTO.LOITER")
    set_hold()

    while not rospy.is_shutdown():
        rate.sleep()

    set_disarm()

注意：以上代码仅供参考，具体实现可能需要根据不同的硬件、软件版本进行修改。