Torque measuring method for robot joint

The invention discloses a torque measuring method for a robot joint, which comprises the steps of collecting (1) an angle value theta 1 of a motor end in real time through a first encoder, and collecting an angle value theta 2 of a speed reducer output end in real time through a second encoder; (2) judging whether a coordinate point (theta1/G, theta2) falls into a no-load area or not, if so, directly executing the step (5), and if not, executing the step (3); (3) calculating a variable quantity delta theta 1; (4) judging whether the variable quantity delta theta 1 is greater than 0 or not, or whether the variable quantity delta theta 1 is equal to 0 but the speed reducer is in a clockwise rotation state at the previous moment, if so, calculating a torsion angle delta according to a formula delta = F < clockwise > (theta 1/G)-theta 2, and if not, calculating the torsion angle delta according to a formula delta = F < anticlockwise > (theta 1/G)-theta 2; and (5) calculating the torque T according to a formula T