Relative Coupling EMPC for High-Precision Contouring Control in Multiaxis Motion Systems With Sensorless Operation Enabled by Kalman Filter

High-precision and high-dynamic contouring control is crucial for applications, such as 3-D printing and precision computerized numerical control machine tools. Existing research suggests that all-pass controllers, which mitigate measurement delays, can achieve optimal position control characteristics. Building on this foundation, this article proposes a novel multiaxis drive control architecture. The proposed strategy consists of two key components. First, the primary controller of the multiaxis motion system is an explicit model predictive controller (EMPC). By integrating “offline computation + online searching,” EMPC ensures unified coordination between motor control and interaxis errors, thereby improving the system's tracking accuracy and collaborative performance. Then, to address position control deviations caused by encoder measurement delays, a strong-tracking Kalman filter is employed to obtain real-time multiaxis speed and position data. In addition, a recursive least squares identification algorithm is used to correct position observation errors resulting from parameter mismatches. Experimental results demonstrate that the proposed strategy significantly enhances the tracking capability of the multiaxis motion system for complex trajectories. Specifically, the absolute single-axis tracking error is reduced by 3.02 mm (representing a relative accuracy improvement of approximately 26.6%), and the absolute contour error is reduced by 5.56 mm (a relative accuracy improvement of approximately 27%).