# Analysis of Longitudinal Braking Stability of Lightweight Liquid Storage Mini-Track Vehicles
## 4 Road Experiment
### Dynamic Stability Experiment
#### 4.2.2 Influence of IV on the Effective Braking Deceleration  
Experimental data for the effective braking deceleration were obtained corresponding to the start, acceleration, movement, and braking of the tracked vehicle at the IVs of 1, 2, and 3 km\(\cdot\)h\({}^{-1}\), respectively, and the corresponding data are shown in Figure 17.  
Figure 16: Dynamic stability test platform of tracked vehicle: 1. Upper computer; 2. the 24 V power supply; 3. data acquisition card; 4. the 200 kg weight; 5. three-axis acceleration sensor; 6. angular displacement sensor; 7. physical prototype of the tracked vehicle.  
Figure 17: Experimental data obtained for effective braking deceleration during starting, accelerating, walking, and braking of a tracked vehicle: (**a**) IV 1 km\(\cdot\)h\({}^{-1}\); (**b**) IV 2 km\(\cdot\)h\({}^{-1}\); (**c**) IV 3 km\(\cdot\)h\({}^{-1}\); and (**d**) comparison of each IV condition.  
Change trends in effective braking deceleration values during starting, accelerating, walking, and emergency braking at different IVs were practically the same. These results indicate that when the TLR and braking deceleration are fixed, change in the movement speed shows a limited effect on the effective braking deceleration.  
The effective braking deceleration of the tracked vehicle shows a sudden change after 10 s of acceleration and 30 s of braking. The remaining stages display an approximately periodic fluctuation, which increases in magnitude between 10 and 30 s. This is due to the sudden acceleration or braking of the vehicle, which causes the forced vibration of its motor, reducer, and pump, among other parts. As such, it intensifies the degree of oscillation of the liquid and the entire body: therefore, the effective braking deceleration fluctuates within a certain range. Furthermore, the higher the speed, the more obvious the superposition effect of forced vibration, and the greater the fluctuation of longitudinal acceleration.  
The experimental data obtained for braking conditions at three IVs were filtered and amplified, as shown in Figure 18.  
Figure 18 shows that after the braking starts, regardless of the value of IV, the longitudinal acceleration decreases to its minimum value at about 30.3 s. When the tracked vehicle is braking, the liquid oscillation and the impact on the tank wall reduce the vehicle braking performance. It results in the actual effective braking deceleration of less than 4 m\(\cdot\)s\({}^{-2}\).  
Once the effective braking deceleration was reduced to the minimum, its value gradually increased; its absolute value decreased more significantly compared to that shown in Figure 14. This was due to the forced vibration of the motor, gearbox, and pump, in addition to other components, which was caused by sudden acceleration or braking, and intensified the degree of liquid oscillation. Compared to Figure 13, the longitudinal force of the liquid was greater and the effective braking deceleration was reduced to a greater extent.  
The variation trend in the effective braking deceleration obtained in the experiment was found to be consistent with the simulation results. However, the time required to decrease it to the minimum value was shorter.