**5. Final remarks**

This work presented the thermal analysis of the Active Magneto-Rheological Knee actuator (AMRK) for lower-limb prostheses and exoskeletons. The AMRK is composed by a motor unit (EC motor, harmonic drive, and MR clutch), responsible for generating positive work, that works in parallel to a MR brake, used to dissipate energy when the knee is subjected to negative work conditions. The proposed configuration is designed to perform a proper walk with low energy consumption [25, 26]. The thermal model for the components of the MR actuator was presented. EC motor, harmonic drive, MR clutch, MR brake, and bearings were modeled to assess the thermal behavior of the knee when subjected to a long walk over the ground. The results indicate that the proposed operating modes are effective to avoid actuator overheating. The maximum temperatures reached in each component are within the tolerances established by the suppliers and no damage is caused to the system, as well as to the MR fluid. The external steady state temperature of the actuator is about 31°C, which does not represent risk for the user. Future work will consider evaluating the temperature of the system under more severe working conditions, such as going up and down stairs.
