Friction Identification of Heavy-Duty Manipulator CMOR Using Markov Chain Monte Carlo Method

The CFETR Multipurpose Overload Robot (CMOR) is a heavy-duty manipulator that will be used for remote maintenance of China Fusion Engineering Test Reactor (CFETR). The transmission efficiency of the heavy-duty manipulator is generally low, which is mainly due to the large friction force of the heavy-duty manipulator compared to a light-duty manipulator. To improve the control performance, it is better to estimate friction in the transmission system. However, since the influence of the load, temperature, speed, and other factors on the friction force of the heavy-duty manipulator has not been studied separately yet, it is difficult to establish an accurate model of friction torque. This research aims to use the method known as Markov chain Monte Carlo (MCMC) to estimate the unknown parameters. The dynamic model has been built based on data on the output torque, current, motor center temperature, displacement, and speed of one joint of the heavy-duty manipulator. The results show that the MCMC method can greatly improve the efficiency of parameter identification and maintain a high level of accuracy.