# Ground Simulation Tests in Two-Dimensional Dynamic Acceleration Environment
## 3 Simulation of Impact Overload Environment
### Loading Test of Impact Overload Environment  
Both the air cannon firing and the electromagnetic clutch engagement commands are sent by the digital output module to the driving system controlled by the relay. The electromagnetic clutch  
Figure 8: Simulation of the revolution speeds of the motor using active disturbance rejection control (ADRC).  
Figure 9: Zoomed-in revolution speeds of the motor using ADRC.  
is controlled by the carbon brush, and the air cannon is controlled by the electric solenoid valve. The response speeds of the two mechanisms are different.  
The revolution speed of the arm is set as 105 rpm. After the air cannon is fired, the electromagnetic clutch is immediately relayed. The measured impact acceleration of the arm is shown in Figure 10. The steady-state normal acceleration of the arm is 11 \(g\). The acceleration rise time is 74.56 ms. The loading time of the launch acceleration is 819 ms, which does not meet the simulation test requirements for the impact overload environment. The electromagnetic clutch has a longer response time than the solenoid valve, causing too long loading time. As can be measured, the electromagnetic clutch has a response time that is 250 ms slower than that of the electric solenoid valve. Therefore, the loading time of the impact acceleration can be regulated by adjusting the operating time sequence of the air cannon launch and the clutch engagement. After the clutch has been engaged for 250 ms, the air cannon is fired.  
The unit being tested is fixed on the arm. The axial direction of the unit being tested points to the normal direction of the arm, and the radial direction of the unit being tested points to the tangential direction of the arm. So, the tangential acceleration of the arm is the radial acceleration of the unit, and the normal acceleration of the arm is the axial acceleration of the unit. The impact overload acceleration is set as 20 \(g\). After 2.5 s of the air cannon being fired, the motor accelerates, and the axial acceleration of the unit being tested is set as 40 \(g\). The 2-D acceleration test results of the unit being tested are shown in Figure 11. The air cannon propels the arm and produces a powerful impact. The radial acceleration of the unit being tested rises instantaneously. After the clutch is engaged, the motor drives the arm to rotate at a constant revolution speed, while the radial acceleration of the unit being tested is zero \(g\). After 2.5 s, the motor is accelerated, and the axial acceleration of the unit being tested reaches 40 \(g\).  
Figure 11: 2-D acceleration test results for the unit being tested.  
Figure 10: Impact acceleration test results for the arm.  
As shown in Figure 11, the loading time of the impact overload acceleration is 120 ms, and the loading time of the flight overload acceleration is 335 ms, which satisfy the speed requirements of the axial acceleration of the unit being tested. However, during the acceleration of the arm, the tangential acceleration occurs, which does not meet the requirements of the simulation test for the radial acceleration of the unit being tested. Therefore, the vector shaft angle needs to be adjusted to track or decompose the resultant acceleration of the arm to achieve dynamically controllable loading of the radial acceleration of the unit being tested.