Abstract:he kinematic accuracy of 3-RRR parallel mechanism was analyzed considering joint clearances and flexible components. The contact force model of revolute joints with clearance was built by taking the energy loss and the friction into account. After modelling the flexible components in 3-RRR mechanism via ANSYS, the virtual prototype of mechanism was constructed on the ADAMS platform. By using this virtual model, the displacements and velocities of center of moving platform were calculated and compared with different sizes of the joint clearance. In order to quantitatively analyze the kinematic accuracy of 3-RRR mechanism, some dimensionless parameters were introduced to further evaluate the influences of the clearance size, rotational speed, and flexibility of components. The results show that the kinematic accuracy decreases with increasing of size of joint clearance in the 3-RRR mechanism. Comparing to rigid components, the velocity error of the moving platform of mechanism with flexible components also decreases. The increase of the input rotational speed enlarges the velocity error of the moving platform remarkably.