Sensitivity-based modeling of error transfer in synchronous cam-linkage mechanisms using a dual-measurement-point approach

Over time, the synchronous cam mechanism experiences progressive wear and tear during operation, ultimately impairing its core performance capabilities.When original design data are unavailable, disk cams are mainly maintained using curve fitting design methods. The choice of measurement points is crucial in this context. Currently, sample data is primarily collected by measuring the inner contour of disk cams for curve fitting to produce replacement cams. However, the synchronization precision at the execution end remains inadequate. To address this issue, this study introduces a method of measuring the center points of rollers to enhance accuracy. This paper develops cam error models for both surveying approaches. By integrating these with the linkage mechanism’s error model—constructed using the Modified Denavit-Hartenberg (MDH) method—an error analysis and comparison are conducted, with output-end sensitivity as the evaluation metric. This reveals the sources of errors and the pattern of error accumulation. Additionally, the synchronous segments of the cam are divided, and techniques such as constrained least squares and orthogonal basis reconstruction are employed to generate optimized cam curves. Experimental validation confirms the effectiveness of these methods. The findings indicate that synchronization errors in both schemes increase proportionally with rotational speed. Under the maximum rotational speed condition, the synchronous error at the execution end of the cam obtained using the new surveying scheme is reduced to 57.2% of that associated with the original scheme. This improvement can be mainly attributed to the fact that the new scheme mitigates the error accumulation effect arising from inner-contour-based radial data transmission and reduces the uncertainty introduced by complex nonlinear geometric mapping. This study constructs a comparative framework for independent error propagation models under two distinct surveying approaches, demonstrating how different measurement references lead to varying degrees of error accumulation at the actuator end. It elucidates the relationship between sensitivity stability and fitting precision, confirming that smooth sensitivity characteristics are essential for minimizing execution-end deviations. These findings offer novel optimization principles for reverse engineering applications. Finally, the proposed method is experimentally validated on an engineering test platform, demonstrating its applicability and potential value for industrial cam repair and remanufacturing.