Online self-sensing detection method and system for loaded mechanical impedance of motor

The invention discloses an online self-sensing detection method and system for loaded mechanical impedance of a motor. Mechanical impedance loaded on the motor is measured indirectly by detecting electrical impedance of the motor. The method comprises the following steps: firstly, three-phase stator current is sampled and transformed into a rotor rotating coordinate system, and a q-axis current component having the same frequency with injected detection voltage is extracted by a band-pass filter; Hilbert transform is performed on the detection voltage and the q-axis current component, and analytic signals of voltage and current are synthesized; complex operation is performed on the analytic signals, and the electrical impedance of the motor is obtained; finally, the mechanical impedance loaded on an output shaft of the motor is calculated on the basis of the coupling relation between the electrical impedance and the mechanical impedance of the motor. The mechanical impedance loaded on the motor is detected by a motor driver under the condition that additional force/torque and a motion sensor are not used, so that the problems of complex structure, large size, high cost, sensor load effect and the like in the traditional mechanical impedance measurement method are solved.