高速动车组机车的安全踏板位置和线路情景对模拟驾驶员的腿部肌肉负荷及视线追踪的影响OA

[Background]High-speed train engineers'lower extremities are constrained by compulsive vigi-lance pedal tasks and limited space beneath the control console during driving.Shifts in alertness triggered by running route observation may share the same mental resource required by moderate-to-low physical exertion.Current re-search on improving cab design and maintaining optimal on-duty attention allocation remains limited. [Objective]To examine variations in lower extremity muscle load,gaze-tracking behavior,and driving performance under various combi-nations of vigilance pedal positions and route scenarios during simulated high-speed train tasks.To identify optimal working condition combinations that promote level and variety of physical activity and facilitate rational attention allocation. [Methods]A 4×2 within-subjects design were employed(4 vigilance pedal position profiles:knee front,side,and any;2 route scenarios:monotonous and complex).Nine male college volunteers were recruited as simulated drivers to perform designated interval driving tasks.Surface electromyography and eye tracking were used to assess leg muscle load and gaze behavior respectively.Task performance and subjective fatigue were recorded. [Results]In all simulation driving tasks,skeletal muscle loads were low with the percentage of maximum voluntary contraction(%MVC)at approximately 4%.No fatigue tendencies were observed within single trial blocks(7 min),and the subjective fatigue ratings remained relatively low.While the activation of the dominant-side tibialis anterior was higher for the knee pedal than for the front(%MVC:3.7%±3.13%vs.1.08%±0.72%)or the side pedals(%MVC:3.7%±3.13%vs.1.4%±0.77%).The activation level of the dominant-side gastrocnemius was higher for the knee pedal than for the other three pedal profiles.For the any pedal condition,the intercept of the instantaneous median frequency curve for the dominant-side rectus femoris was lower in the monotonous route than in the complex route[(111.18±35.78)Hz vs.(153.33±39.12)Hz].Among eye-tracking metrics,total fixations were higher during knee-level pedaling than side pedaling,while more saccades were recorded in monotonous routes than in complex ones.Regarding task performance,the any pedal yielded fewer missed signals than the front pedal,with 2/3 and 1/3 of participants preferring the front and knee pedals,respectively.The activation levels of the dominant tibialis anterior and dominant gastrocnemius muscles during the knee pedal×complex route combination were higher than any combination involving the front pedal.No statistically significant effect of pedal position or route scenario was found on other indicators. [Conclusion]The combination of knee pedal and complex route provides an optimal working setting for maximizing leg muscle mobility without compromising attention allocation or driving performance.It is recommended that train engineers modulate attention during monotonous routes to avoid emotional tension and increased muscle strain caused by over-monitoring.Given the ergonomic characteristics of high cognitive load,low physical exertion levels,and highly restricted lower limb mobility among high-speed train engineers,future cab designs should consider incorporating knee-level vigilance pedal and adjust safety alertness rules to allow reset via either front or knee pedal.