Unfortunately, the examples available for OpenMANIPULATOR-P do not offer the effort controller.
If you need to use it, you'll need to create the controller for your purpose.
You may find more relative information about the effort controller from ROS community such as discourse.ros.org.
I did create my own controller "open_manipulator_p_controllers/ComputedTorqueController" (look at the first picture), but it alway like the " effort_controllers/JointTrajectoryController". Both of them can control the robot only in the simulation software gazebo. When I try to control the real robot, them can't work. (all the joints seem to be locked)
why the controller can work in simulation, but can't in real robot? Is there have some matter in the hardware interface which downloads from the github (look at the second picture), or if I need to change some config? (I changed the interface type, look at the third picture)
the first picture:
the second picture:
the third picture: