High-precision reducers, such as planetary gear reducers, harmonic reducers, and cycloidal pinwheel reducers, are widely used in various applications, including robotic joints, CNC machine tools, automated production lines, and high-precision measuring instruments. However, backlash and internal resistance in these reducers significantly impact their performance. Backlash can decrease positioning accuracy, compromise motion stability, and delay dynamic response, while high resistance reduces transmission efficiency, increases temperature rise, and causes power transmission losses, thereby affecting the overall performance and lifespan of the system. Therefore, the development of low-backlash, low-resistance reducers is of particular importance. This study focuses on the planetary gear transmission system and introduces a backlash elimination mechanism. The transmission characteristics of the system are analyzed, and the rationality of the designed transmission system is verified. The research findings provide theoretical support and practical reference for the design and improvement of backlash elimination mechanisms in planetary gear reducers.