For traditional robots, the robot with large load will be more difficult to control, which greatly affects the efficiency and stability of the robots.
The main reasons are given as follows:
(1) The traditional robot encoder is installed on the input side of the reducer, but the reducer has a back gap. With the length of the arm span, the deviation of the end point caused by the back gap will also be enlarged.
(2) In the low speed area, when the static friction and dynamic friction torque switch, the input axis rotates at a uniform speed, and the output axis may show a fast and slow jump movement, and the heavier the load, the positive pressure and friction will increase, and the phenomenon of "crawling" will be more obvious.
(3) The torsional stiffness of the section of the robot connecting rod is certain. With the length of the arm span, the torsion Angle of the end increases, which will reduce the resonance frequency of the whole mechanical transmission chain, and then affect the control bandwidth of the servo, and reduce the control performance and precision.
(4) In practice, with the increase of large load robot inertia, the natural frequency of the system decreases, the response speed becomes slower, the stability becomes worse, and the overshoot becomes larger.
(5) The robot has no active safety protection function.
