Hello everyone,
I am trying to use the SITL to simulate a Rover, and I would like to link GAZEBO to the simulation. My SITL works well but the link between gazebo and the simulation is not made… I don’t know how to do.
I do these two commands in parallel :
For SITL
sim_vehicle.py -v Rover -f rover-skid --map --console
For GAZEBO
gz sim -v4 -r ackermann_steering.sdf
I don’t know how to link a rover models to the simulation 
If someone has any idea, please help me 
THANK YOU !!
please someone can help me 
Ah… I’m interested in this topic also. 
Hi @sarah_gress, if this is the ackermann_steering.sdf example in gz-sim/test/worlds, it doesn’t have any integration with ArduPilot, so you’d need to add the ardupilot_gazebo plugin and configure it to forward commands to the topics expected by the AckermannSteering controller plugin. In this case you’d also want to use a standard rover rather than a skid steer one, as the Ackermann controller expects a steering and throttle input, where a skid-steering rover requires a left and right throttle.
If you would like a skid-steering example you could look at the example here: SITL_Models/Gazebo/docs/WildThumper.md at master · ArduPilot/SITL_Models · GitHub.
On the other hand if it’s an Ackermann (i,e, car steering) rover you want then I could look into configuring the plugin to support the gz-sim example.
Update
The zip file below contains the modifications to gz-sim/examples/worlds/ackermann_steering.sdf needed to get it working with the ardupilot_gazebo plugin. It is assumed that you have built the plugin following the instructions here: Using SITL with Gazebo — Dev documentation
ackermann_steering.sdf.zip (3.2 KB)
I’ve annotated the changes in the file, but to summarise the things required are:
no link errors in the console as the FC will wait for a valid IMU reading which never arrives.<plugin filename="gz-sim-imu-system"
name="gz::sim::systems::Imu">
</plugin>
base link (or chassis in this case). Note the orientation. The z-axis must be pointing down.<sensor name="imu_sensor" type="imu">
<pose degrees="true">0 0 0 180 0 0</pose>
<always_on>1</always_on>
<update_rate>1000</update_rate>
</sensor>
cmd_vel, but forwards steering and throttle commands separately.<plugin
filename="gz-sim-ackermann-steering-system"
name="gz::sim::systems::AckermannSteering">
<steering_only>true</steering_only>
<use_actuator_msg>false</use_actuator_msg>
<left_joint>front_left_wheel_joint</left_joint>
<left_joint>rear_left_wheel_joint</left_joint>
<right_joint>front_right_wheel_joint</right_joint>
<right_joint>rear_right_wheel_joint</right_joint>
<left_steering_joint>front_left_wheel_steering_joint</left_steering_joint>
<right_steering_joint>front_right_wheel_steering_joint</right_steering_joint>
<kingpin_width>1.0</kingpin_width>
<steering_limit>0.5</steering_limit>
<wheel_base>1.0</wheel_base>
<wheel_separation>1.25</wheel_separation>
<wheel_radius>0.3</wheel_radius>
<min_velocity>-1</min_velocity>
<max_velocity>1</max_velocity>
<min_acceleration>-3</min_acceleration>
<max_acceleration>3</max_acceleration>
</plugin>
<plugin
filename="gz-sim-joint-controller-system"
name="gz::sim::systems::JointController">
<joint_name>rear_left_wheel_joint</joint_name>
<use_force_commands>true</use_force_commands>
<use_actuator_msg>false</use_actuator_msg>
<p_gain>0.1</p_gain>
<i_gain>0.0</i_gain>
<d_gain>0.0</d_gain>
</plugin>
<plugin
filename="gz-sim-joint-controller-system"
name="gz::sim::systems::JointController">
<joint_name>rear_right_wheel_joint</joint_name>
<use_force_commands>true</use_force_commands>
<use_actuator_msg>false</use_actuator_msg>
<p_gain>0.1</p_gain>
<i_gain>0.0</i_gain>
<d_gain>0.0</d_gain>
</plugin>
gz-transport message bus where they are picked up by the AckermannSteering and JointController plugins. The topic names are the default values as documented in the controller plugin header files.<plugin name="ArduPilotPlugin"
filename="ArduPilotPlugin">
<fdm_addr>127.0.0.1</fdm_addr>
<fdm_port_in>9002</fdm_port_in>
<connectionTimeoutMaxCount>5</connectionTimeoutMaxCount>
<lock_step>1</lock_step>
<gazeboXYZToNED degrees="true">0 0 0 180 0 90</gazeboXYZToNED>
<modelXYZToAirplaneXForwardZDown degrees="true">0 0 0 180 0 0</modelXYZToAirplaneXForwardZDown>
<imuName>chassis::imu_sensor</imuName>
<!-- steering -->
<control channel="0">
<jointName>front_left_wheel_steering_joint</jointName>
<useForce>1</useForce>
<multiplier>-1.571</multiplier>
<offset>-0.5</offset>
<servo_min>1000</servo_min>
<servo_max>2000</servo_max>
<type>COMMAND</type>
<cmd_topic>/model/vehicle_blue/steer_angle</cmd_topic>
</control>
<!-- throttle -->
<control channel="2">
<jointName>rear_left_wheel_joint</jointName>
<multiplier>100.0</multiplier>
<offset>-0.5</offset>
<servo_min>500</servo_min>
<servo_max>2000</servo_max>
<type>COMMAND</type>
<cmd_topic>/model/vehicle_blue/joint/rear_left_wheel_joint/cmd_vel</cmd_topic>
</control>
<control channel="2">
<jointName>rear_right_wheel_joint</jointName>
<multiplier>100.0</multiplier>
<offset>-0.5</offset>
<servo_min>1000</servo_min>
<servo_max>2000</servo_max>
<type>COMMAND</type>
<cmd_topic>/model/vehicle_blue/joint/rear_right_wheel_joint/cmd_vel</cmd_topic>
</control>
</plugin>
The default PID controllers require tuning for the vehicle to respond well. These values are are reasonable start:
ATC_STR_RAT_P 2.500000
ATC_STR_RAT_D 0.010000
ATC_STR_RAT_FF 2.000000
ATC_SPEED_P 1.000000
ATC_SPEED_I 0.100000
Here is the vehicle running an AUTO mission around a large rectangle. The steering tune is acceptable and the nav controller seems to work well with defaults.
Thank you for your time.
I am a newbie in gazebo, and ardupilot sitl, then I am not sure to know how to add good plugins and setup a good configuration… could you help me with precisions please ??
Actually, I would like to use a steering-car yes.
thank you
@sarah_gress Sorry for cut in.
@rhys I’m interested in Ackermann (i,e, car steering) rover. And I hope to setup an simulation environment with obstacles. Can you guide us through the setup?
As I have one AKM Rover with ArduRover 4.5.2, see below:
