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Simulation GIMBAL using Ardupilot and Gazebo

Robotics / uav / ardupilot / sitl

Gazebo

topics

  • /gimbal/cmd_roll
  • /gimbal/cmd_pitch
  • /gimbal/cmd_yaw

pub example

pitch/tilt 90 degree down
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gz topic -t /gimbal/cmd_pitch -m gz.msgs.Double -p 'data: 1.575'
pitch/tilt horizon
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gz topic -t /gimbal/cmd_pitch -m gz.msgs.Double -p 'data: 0'

gz topic -t /gimbal/cmd_pitch -m gz.msgs.Double -p 'data: -0.2'
yaw
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# flu position ccw
gz topic -t /gimbal/cmd_yaw -m gz.msgs.Double -p 'data: 1.0'
gz topic -t /gimbal/cmd_yaw -m gz.msgs.Double -p 'data: 0'
gz topic -t /gimbal/cmd_yaw -m gz.msgs.Double -p 'data: -1.0'
roll
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gz topic -t /gimbal/cmd_roll -m gz.msgs.Double -p 'data: 1.0'
gz topic -t /gimbal/cmd_roll -m gz.msgs.Double -p 'data: 0'
gz topic -t /gimbal/cmd_roll -m gz.msgs.Double -p 'data: -1.0'

Ardupilot plugin

Convert Ardupilot channel to gazebo command

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<control channel="8">
    <jointName>gimbal::roll_joint</jointName>
    <multiplier>1.047197551196</multiplier>
    <offset>-0.5</offset>
    <servo_min>1100</servo_min>
    <servo_max>1900</servo_max>
    <type>COMMAND</type>
    <cmd_topic>/gimbal/cmd_roll</cmd_topic>
    <p_gain>2</p_gain>
</control>

raw_cmd = (pwn-pwn_min) / (pwm_max-pwm_min) raw_cmd -> [0, 1]

cmd = multiplier * (raw_cmd+offset)

roll

  • multiplier = π ≈ 3.14159
  • offset = -0.5
cmd
-pi/2 0
0 0.5
pi/2 1

pitch

  • multiplier ≈ 1.7708
  • offset ≈ -0.11296
cmd
-0.2 0
pi/2 1

yaw

  • multiplier = π ≈ 3.14159
  • offset = -0.5
cmd
-pi/2 0
0 0.5
pi/2 1

Ardupilot

Ardupilot plugin channels

GZ_CH (0)
8 ROLL servo_9
9 PITCH servo_10
10 YAW servo_11

Ardupilot param
SERVO9_FUNCTION 8 (1-roll)
SERVO10_FUNCTION 7 (1-pitch)
SERVO11_FUNCTION 6 (1-yaw)

alt text

bash ros2 service call /mavros/set_message_interval mavros_msgs/srv/MessageInterval "{\"message_id\": 285, \"message_rate\": 2 }"