How to programatically set joint friction torque?

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Thanks! One follow-up question: any ideas on how to pass argument from source code to this plugin? Different cars will apply brake torque on different set of joints, but I'd like to use a same plugin. Also the required friction torque is computed in the source code. Can I use ros parameter server to set the joint names and use a subscriber in the plugin to get the required friction?

Sure, make the arguments part of the SDF for each instance of the plugin. SDF allows aribtrary XML tags to be passed to a plugin`<plugin name="my_fancy_plugin_instance" filename="libMyFancyPlugin.so"><max_brake_torque>12345</max_brake_torque></plugin>`. See the random velocity plugin for an example http://gazebosim.org/tutorials?tut=plugins_random_velocity

Ah, sneaky edit about ROS parameters! I believe you can initialize a ROS node inside the plugin, and from there do whatever you like through the ROS API. The plugins will need a way of identifying which which ROS param belongs to them, but the SDF arguments gives a way to name the instances.