The Magneto-Thermal Analysis of a High Torque Density Joint Motor for Humanoid Robots

The high power capacity of humanoid robot is desired for application of running or jumping motions, and the new generation robot formulate the need for a low-mass high-torque motor. A frameless motor has been designed by the group, it is very important to calculate the thermal field of the motor and get the conclusion for the choice of the motor parameters. The magneto-thermal coupling analysis of the motor was carried out based on the thermal network by the iterative calculation. By using the equivalent thermal network method, the elements copper loss and core loss is coupled into elements in thermal analysis by keeping the same mesh structure between magnetic and thermal analysis. Other losses such as air friction loss, rotor loss are included in the model. A temperature rise calculation program was written and different position temperature distribution was obtained. In the meantime, the steady-state temperature of BLDC was calculated by using the finite element method (FEM). The experimental results show that, the actual torque performance of the motor can reach the target of our design, at last, temperature calculation results obtained from two different methods were compared with experimental data, and the correctness of the calculation model is verified.