Calculation and testing approaches of the kinematic envelope for suspended monorail vehicles

The line-side clearance gauge has a significant influence on the economy and operational safety of suspended monorail transit systems, for which there are currently no relevant specific standards or specifications. The important basis for determining the line-side clearance gauge is the kinematic envelope of the vehicle, while few studies have been conducted on its calculation or testing approaches currently. In this paper, the kinematic envelope calculation formulas are derived for a typical suspended monorail vehicle based on geometry and force analyses, then according to the proposed formulas, the special motion posture of suspended monorail vehicle is revealed and its occurring mechanism is analyzed in detail. Furthermore, a full-scale field test is conducted to verify the derived formulas, which shows the tested motion posture is in good agreement with that analyzed by the formulas. Finally, the effect of key parameters on the kinematic envelope is studied based on the formulas, indicating that appropriately reducing the rotation angle of the bolster can effectively decrease the kinematic envelope without sacrificing ride comfort. These results can be directly used to determine the kinematic envelope, or even as a reference for establishing standards for the line-side clearance gauge of suspended monorail in the future.