Research On Pedal Operation Comfort Of Crawler Excavator

Crawler excavator working environment is bad,the working condition is complex and the driver’s working time is long,the work intensity is high.If the equipment does not have a good operating comfort will cause the driver body fatigue,low work efficiency,cause serious skeletal muscle diseases will also cause safety accidents.Therefore,it is very important to improve the operator’s comfort of crawler excavator.Pedal operation comfort is an important factor for man-machine operation comfort of crawler excavator.In this paper,the comfort of pedal operation is studied in combination with the inclined attitude of the cockpit caused by working conditions.A biomechanical model of pedal operation based on AnyBody Modeling System was constructed.From the biomechanical perspective,the stepping position of the pedal was simulated under five oblique angles by using virtual simulation technology.The improved pedal layout can improve the operating comfort of the pedal and provide reference for the man-machine layout of excavator cab.According to the improved pedal layout,an electromyography test was conducted to construct a pedal-operating comfort prediction model of crawler excavator based on LSTM neural network.The human body size,cockpit tilt Angle and electromyographic characteristic values were input,and the subjective comfort score was output to study the relationship between subjective comfort perception of pedal operation and objective physiological indicators.To achieve the purpose of forecasting the subjective comfort score by inputting objective evaluation index.It improves the objectivity and accuracy of pedal operation comfort research and makes the evaluation results more scientific and reliable.The research mainly includes the following aspects:(1)Establish a two-dimensional mechanical model of pedal operation of crawler excavator driver.According to the characteristics of pedal operation of the driver,a mechanical model was established,and the joints of the driver’s lower limbs were simplified into hinge structures.Considering the relative mass,length distribution and stress of the driver’s lower limbs in each ring segment,the influence of the spatial layout of the pedal on the pedal operation comfort of the crawler excavator was clearly studied according to the torque balance.(2)To establish a skeletal muscle model based on AnyBody.The driver-seat-pedal model is established and the initial state of the driver is defined.The mechanical constraints of human lower limbs were analyzed,and the running tracks of the foot in front pedal operation and back pedal operation were calculated,so that the ankle joint was in a neutral position during pedal operation,and the motion control of the driver-seat-pedal model was realized.An electromyographic test was designed to verify the accuracy and rationality of the established driver-seat-pedal model through Pearson correlation analysis of the characteristic values of electromyographic signals and corresponding muscle activation.(3)Step simulation test of pedal layout.Taking the tilting attitude of the cockpit caused by the working conditions of the excavator as a whole,the biomechanical simulation research was carried out on the stepping position of the pedal at five tilting angles in the X,Y and Z directions with H as the origin of spatial coordinates.The research system of pedal layout biomechanics was constructed by AHP.The principal component analysis of PCA was used to reduce the dimension of the indicators to be studied and calculate the weight.The biomechanical scores of each step position were calculated using TOPSIS-GRA’s multi-attribute decision method.The changes of biomechanical scores of pedal layout in X,Y and Z directions were analyzed.The pedal layout position with the highest biomechanical score is selected as the improvement scheme of pedal layout.(4)Establish a pedal operation comfort evaluation model based on LSTM neural network.According to the improvement scheme of pedal layout,20 subjects were gathered to perform pedal operation experiments under different cockpit tilt angles.The output of comfort evaluation can be obtained directly through the input of driver body data,electromyographic characteristic value and cockpit tilt Angle.Based on the analysis and research of actual data,the prediction model of pedal operation comfort of crawler excavator under the tilting Angle of cockpit based on LSTM deep learning has high accuracy,and improves the scientific and reliability of comfort research.