A sinusoidal torque excitation method based on the inertia load is proposed by combining the inertia load with the time variable characterizing the dynamic torque signal. The dynamic torque excitation mechanism based on the inertia load is analyzed

and the relation between sine torque and the time variable is established by using an incremental photoelectric encoder as the angular acceleration sensor. Meanwhile

the pulse counting error is compensated. The sinusoidal torque excitation system is built

and the effective torque output is realized by compensating the friction torque

and the discrete relationship between the number of pulses and the time variable is obtained. After Fourier transform and filtering

the nonlinear least square fitting method is used to identify the parameters of sinusoidal torque excitation. By loading different sinusoidal torque excitation

compared with the measured torque of sensor

the result of sinusoidal torque of time scale is consistent with it

and the method is realized. This method can be applied to the analysis and processing of linear combination excitation signals and the calibration of torque sensors.