In order to comprehensively evaluate the driver's vibration comfort under different vibration conditions, eighteen subjects were required to drive a tractor at different speeds on field and asphalt roads respectively in the real vehicle experiment. The sEMG signals and vibration acceleration signals of the subjects were recorded. And the time-frequency domain analysis of sEMG signals and acceleration signals were used to determine the relationship among the characteristic indexes, tractor speed and road surfaces. The relevance analysis showed that there was a significant correlation between the integral electromyography (iEMG) and median frequency (MF) of the middle scalene muscle, erector spinae muscle and gastrocnemius muscle, the RMS of weighted acceleration (a(w)) of the neck, waist and legs, and the subjective comfort feelings. It was proven that the tractor speed had a significant impact on human body vibration based on the ANOVA result (p < 0.05). With the increase of running speed, the time domain indexes of sEMG signals including iEMG, RMS and the vibration acceleration signals of the testing body parts increased significantly, while the amplitudes of frequency domain indexes decreased. Therefore, a quantitative regression evaluation model for the comfort of the neck, waist and legs integrating the sEMG and vibration signals was established, and its relative errors were 5.05, 4.38 and 6.12% respectively. This proposed assessment model can combine characteristics of the partial and overall vibration response of human body effectively, predict the tractor driver's vibration comfort accurately, provide a theoretical basis for the evaluation of tractor cab vibration comfort.

In the field of armored vehicles, up to 70% of accidents are associated with low levels of situational awareness among the occupants, highlighting the importance of situational awareness in improving task performance. In this study, we explored the mechanisms influencing situational awareness by simulating an armored vehicle driving platform with 14 levels of experimentation in terms of five factors: experience, expectations, attention, the cueing channel, and automation. The experimental data included SART and SAGAT questionnaire scores, eye movement indicators, and electrocardiographic and electrodermal signals. Data processing and analysis revealed the following conclusions: (1) Experienced operators have higher levels of situational awareness. (2) Operators with certain expectations have lower levels of situational awareness. (3) Situational awareness levels are negatively correlated with information importance affiliations and the frequency of anomalous information in non-primary tasks. (4) Dual-channel cues lead to higher levels of situational awareness than single-channel cues. (5) Operators’ situational awareness is lower at high automation levels.

Nowadays, lumbar supports are applied when designing tractor seats to address the issue of tractor operators’ lumbar discomfort. This research aimed to investigate the effect of lumbar support on ride comfort using various lumbar support thicknesses and running velocities based on body pressure distribution measures and subjective comfort evaluations. The repeated measures ANOVA results revealed that the lumbar support thickness (p < 0.05) and running velocity (p < 0.05) had a prominent, main effect on the pressure distribution indexes, and the interaction effect between them was also significant (p < 0.05). As the lumbar support thickness increased, the degree of comfort at the waist, thigh, elbow, and for the overall body first increased and then decreased, while shoulder comfort was reduced continuously. There was an obvious relationship between the outcome of the subjective comfort assessment and the pressure distribution indexes. The 3 cm thick lumbar support did not enhance ride comfort significantly, whereas the 9 cm thick lumbar support imposed excessive pressure on the lumbar spine, thus leading to an excessive forward inclination of the lumbar spine and increased tiredness. Most tractor operators selected the 6 cm thick lumbar support. This research provides insights from practical applications that may be useful for the design and assessment of tractor seats, based on body pressure distribution, to increase overall ride comfort and reduce operator fatigue.