Modelling of transmission accuracy of a planetary roller screw mechanism considering errors and elastic deformations

Based on the motion principle of a planetary roller screw mechanism (PRSM) converting the rotary motion into linear motion, a calculation model of the transmission error under free load is established considering the error and clearance, as well as a transmission error model under different working loads considering the elastic deformation. The error is mainly concerned with PRSM manufacturing errors and assembly errors, the theoretical transmission error curve obtained by measuring the accumulative error and flank angle of the thread, the coaxial error of the screw thread, and the deviation error and eccentric error. Besides, an error analysis and measurement of the experimental system is performed to verify that the system meets the experimental requirements and is conducive to obtain accurate experimental results. Lastly, the transmission error experiment of the PRSM prototype under free load and different working loads are further conducted. The experimental data of the transmission error are compared with the analytical solution presented in this paper, and the results show that the difference is 20.1% under the free load condition and is less than 15% under different working loads.