What is the best way in mujoco to obtain joint torque readings similar to what we obtain from a real robot's sensor. It seemed to me that the mjData.qfrc_applied can be one source to read such sensor readings, but its values for me has been always zero and seemed more like a placeholder for giving input torques to the simulator rather than getting output. Another way which seemed to me based on the documentation of Mujoco was reading mjData.qfrc_actuator, where if we have used motors would be equal to mjData.ctrl. One more way also seemed defining a torque sensor for each joint and calculating the torque magnitude obtained from each, but this seemed a bit messy. In addition, mjData.qfrc_inverse also seemed another alternative but was not sure if in case of collision or contact it may be a good choice. So I was wondering given the torque sensors that are usually available in robot arms, what might be the best way to represent their outputs in Mujoco, e.g., a robot arm such as Franka Emika which possibly has strain gauges or current measurements for its torque sensors.