爬楼轮椅座椅姿态调节机构的可靠度及灵敏度分析

Reliability and Sensitivity Analysis of Stair Climbing Wheelchair Seat Posture Adjusting Mechanism

爬楼轮椅座椅姿态调节机构为一新型两自由度交叉四连杆机构,其运动精度直接影响着爬楼轮椅运动的稳定性。针对座椅姿态调节的交叉四杆机构,利用矩阵的方法建立了机构输入、输出关系的运动精度分析模型,进而建立了机构运动精度的可靠度及灵敏度数学模型。在基本尺寸误差和运动副间隙误差的基础上,求解出了三种运动副间隙误差情况下机构运动精度的可靠度。同时,也求解出了在不考虑运动副间隙误差情况下机构中各基本参数的可靠性灵敏度,最后利用Matlab进行仿真发现机构保持了较高的可靠度及适当增加杆长可改善机构的灵敏度。

As a new-type two-degree crossing four-bar mechanism,the floor-climbing wheelchair seating posture regulating mechanism will affect stability of floor-climbing wheelchair movement through the kinematic accuracy. Specific to seating posture regulation,a matrix method was used to establish the kinematic accuracy analysis model by aiming at input/output relationship of the mechanism. Then,the mathematical model for reliability and sensitivity of mechanism accuracy was established. On the basis of basic dimension errors and joint clearance errors,reliability of mechanism accuracy under three joint clearance errors was solved. Meanwhile,the reliability and sensitivity of basic parameters without considering joint clearance errors were also solved. At last,Matlab was used to simulate,finding that the mechanism remained the higher reliability. The sensitivity of the mechanism could be improved by increasing rod length suitably.