I saw in a web forum that there are three options for effort_controllers

effortcontrollers 1)jointeffortcontroller 2) jointpositioncontroller 3) jointvelocity_controller

in case of (2) the jointpositioncontroller it seems that the default position is the position of the description of the robot. So if we select jointeffortcontroller, what would the default effort that will be applied to the joints and , is it possible to specify these initial controller inputs in the launch files?