When designing or verifying the layout map of the vehicle for key hard points of the vehicle, the determination of key hard points is the basis for other layout analysis. The determination of hard points generally refers to the relevant contents of the database of competitive prototypes and design companies, and is constantly adjusted and finalized on the basis of comprehensive considerations. The key hard points mainly include dimensional hard points, contour hard points, performance hard points, layout hard points, motion hard points, and regulatory hard points, such as the tire model, front and rear wheel center coordinates, and front and rear H point coordinates. C (Cowlpoint) point, D (Duckpoint) point, pedal center coordinate (especially the reference point of the accelerator pedal), the center point of the steering wheel, the upper coordinate point when the shift handle is idle, and the center coordinate point of the rear end surface of the crankshaft of the engine.
The key dimensions of the vehicle include the internal dimensions and the external dimensions. The internal dimensions include length dimension, width dimension, height dimension, angle dimension, and pedal group size; the external dimensions include length dimension, width dimension, height dimension, and angle dimension. Each size is given a code. The SAE standard consists of a size type, a number, and a suffix. For example, L101 represents the wheelbase, and H61-1 represents the first row of human head space.
Static parameter measurement The static parameter measurement includes vehicle attitude measurement, prototype basic static dimension measurement, ground clearance and axle load measurement, and point cloud scanning. Here, only the measurement of the entire vehicle pose is used as an example. The main equipment used for the measurements were prototypes, coordinate measuring machines, dummy models, standard weights, plumb lines, label sheets, vernier calipers, and tire pressure gauges.
The measurement steps are as follows: 1) Understand the basic parameters and technical status of the prototype vehicle, collect prototype vehicle technical parameters and specify the measurement purpose; 2) Check whether the measurement device is in normal working condition, whether the accuracy meets the requirements, and check whether the weight and quantity of the load are Satisfy the requirements, check whether the required equipment is complete; 3) check the working status of the sample car, whether the vehicle internal load meets the requirements, whether the fuel tank, coolant, etc. of the fuel tank meet the requirements, and adjust the tire pressure to the required state; 4) smooth the docking of the vehicle In the coordinate measuring machine platform, the former rear wheel center and the left and right guide rails are used as the reference for adjustment, and the left and right symmetry of the vehicle is ensured as much as possible; 5) At the wheel center and the wheel cover (in order to facilitate the measurement of the probe, generally the center of the wheel center is generally above the distance Mark the mark point at the edge of the wheel cover 2cm. Require that the height is as symmetrical as possible. 6) Measure the height of each point in the preparation state and record the value: The measurement data should be guaranteed more than 2 times. If the 2 measurement data differ by more than 3mm, the data should be recalibrated. 7) Load in turn according to Table 1, and measure the data of the left and right body points and wheel center points of each state until full load; 8 Usually the two design teams all measurement data are completed, in comparative analysis, the accuracy of the inspection data.
Load condition Rear row Rear trunk Condition - Conditioning + Driver 68-7 Conditioning + 2 persons 68 × 2-7 × 2 Conditioning + 3 persons (Design condition) 68 × 2687 × 3 Conditioning + 4 persons 68 × 27 ×4 Conditioning +5 persons 68×268×37×5 full load 68×268×37×5+n(kg) Table 1 Loading scheme Note: The condition of the conditioning complies with the standard: GB/T 3730.2-1996, and the loading capacity is based on the models. Different standards and specifications. Full load status: Curb weight + 5 persons + n (kg).
The mathematical model of the vehicle attitude measurement data processing is to fix the vehicle body in an approximately horizontal state and reflect the suspension stroke by changing the position of the wheel up and down. The specific measurement process is to approximately fix the tire, and the suspension stroke is reflected in the change of the upper and lower positions of the vehicle body. The difference between the measurement and the digital model is that the fixed parts are different, but the relative relationship is the same.
Change in state of each wheel eyebrow: ZZi=Z0-Zi, (i=1, 2,..., 7) Wheel center change in each state: â–³Zci=Zc0-Zci,(i=1,2,...,7) Suspension Stroke: â–³Z = â–³ Zi - â–³ Zci, (i = 1, 2, ..., 7) where Zi is the fender eyebrow coordinate and Zci is the corresponding wheel center coordinate.
The point cloud data processing is affixed to the selected area of ​​the reference sample car with circular identification points, squares and cross-shaped identification blocks, and identification reference lines, captured by the camera in a selected area, and processed by a computer-specific software to process the captured pictures. The identification points consist of frame points, as shown in Figure 1. Then, the scanning area is scanned by the scanner. All the block clouds obtained by the scanning are calculated and analyzed by dedicated software, and outer contours, interior surfaces, front cabins, and chassis layouts are sequentially inspected for external points. The surface is matched by the positioning point and the frame point. Finally, the alignment analysis and data verification are performed and the vehicle coordinates are unified to form a complete vehicle contour point cloud. Finally, the surface is generated by the reverse analysis software, as shown in FIG. 2 and extracted. The borderline and dimension data of the entire vehicle and main components.
Mechanical layout analysis The mechanical layout analysis includes the front cabin, chassis, cabin seats and operating part layouts, etc. The human body layout is used to illustrate the analysis method. 1) Car seat H point Car seat H point refers to the point of connection between the human torso and the thigh in a 2D or 3D model of a human body model, that is, the point of defect (according to the application of different points H expression is also different design H point, Such as DesignH-point and ActualH-point, H point determines the driver's comfort, maneuverability, safety and visibility, and describes the driver's performance in the driving process and the relationship between the cab environment. This device should use the appropriate leg length data shown in Figure 3 (select appropriate percentile dummy according to design requirements) and install it in the final position of the seat as specified by the manufacturer in the normal driving or riding position. The car seat H point is measured by the H dot mark on the three-dimensional H point device. The outer H point mark on the three-dimensional H point device shown in FIG. 3 is deviated 196.5 mm from the center, ie, the H point is measured.
2) Analysis of the front seat trajectory According to the seat point cloud, the Y direction value of the last lower H point is corrected to determine the last H point of the front seat. According to the seat point cloud in different states, the preliminary analysis of the adjustment range of the H point. If the seat is allowed to be disassembled, the seat adjustment mechanism can be scanned.
3) Analysis of driver body layout Initially deal with the accelerator pedal surface, the front floor surface and the last lower H point, and arrange the 95% human body 2D template, as shown in FIG. 4 .
The SAE step is used to further analyze the human R point, which refers to a design reference point on the seat, which is the design reference point specified by the seat manufacturer. Taking into account all the adjustments of the seat (horizontal vertical and tilt), the seat reference point determines the final position of the seat during normal driving or riding, and it characterizes when the 95% manikin is placed on the seat as required The actual H point should coincide with the seat reference point. Usually 50% and 95% of human body size are used in ergonomics design. 5% of female humans are generally not used, but human-machine calibration is required. To obtain data that is closer to its design state, the SAE 95% layout curve is used to obtain the R point. If the seat stroke length is less than 95% of the curve, it is determined with the last bottom point, as shown in FIG. 5 .
Ergonomics Analysis Ergonomics analysis mainly includes ride comfort, human sitting posture, access convenience, seating space, vision, size and visibility of various operating parts, operating space, storage box or shelf Dimensions or hand-operated space, accessibility, openability of the engine compartment lid and trunk lid, accessibility analysis, passability analysis, etc. To complete the above ergonomic analysis and evaluation, we must first determine the H point and deal with the ground line of each state, and only take the determination of the eye ellipse as an example.
1) Definition of eye ellipse The ellipse of car driver's eye refers to the statistics of the position of their eyes in the body coordinate system after the driver of different sizes adjusts the seat to the desired position according to his or her will and takes the seat in the normal driving posture. The distribution graph is called the ellipse of the driver's eye because the graph of the statistical distribution is elliptical.
2) The size of the eye ellipse template and its positioning eye ellipse template is related to the percentile of the human body and the seat level adjustment stroke (L23). According to the difference in the seat horizontal adjustment stroke, it is divided into 2 sets, as shown in Table 2. . One set of eye ovals for L23 at 1133 mm and the other set for eye ovals with L23 greater than 133 mm.
Summarizing the basic idea of ​​the benchmarking analysis of the reference sample vehicle, based on the measurement of the reference sample car, the main static parameters of the sample car are obtained, and the obtained data are processed and analyzed, with emphasis on the analysis of the human body arrangement and the ellipse of the eye. Determined and the A-pillar binocular obstacle angle measurement and calibration, and finally completed the basic dimensions of the vehicle engineering drawings.
Electric Vehicle,Mini Electric Car,Fully Enclosed Electric Scooter,Fully Enclosed Electric Mobility Scooter
JIANGSU ELEGANCE VEHICLE CO., LTD. , https://www.mawayra-ev.com