Testing

To evaluate and measure the many forces that the UAS will experience, a 6-axis load cell will be utilized. This load cell allows us to measure forces in all X, Y, and Z directions. The maximum load that can be measured along the X and Y axis is 1000 N. In the Z axis, the maximum load that can be measured is 2500 N. This large margin of measurment is sufficient for the application which it will be applied.

INSTRUMENTATION

The load cell is positioned on top of the pitch control table so that as the pitch and yaw angles change, the z axis of the load cell is always coincident to the z axis of the UAS. This is important because it eliminates additional calculations to acquire the loads the UAS experiences. Since the UAS is distanced from the load cell, this creates a moment force reading. This extra moment force must be accommodated when measuring the forces acting on the UAS.

Data Acquisition and Analysis

To acquire data from the load cell, a data acquisition system must be utilized. In our case, the BX8 is ideally suited for use with 6-axis sensors requiring axis load calculations. The sensor coefficient matrix can be loaded internally into the BX8 via software interface and the outputs are actively scaled according to the calculations. BlueDAQ is the software used to acquire and process data from the load cell.

Acquired Load Cell Data

UAS Drag force

Now that we can measure the forces in the X, Y, and Z direction of the load cell, this information translates to our drag forces experienced by the UAS. We will measure the drag force over time at a given wind speed.

This data can be used to analyze the drag force induced on the UAS at variable pitch and yaw angles. This is useful because we can manipulate rotor RPMs, rotor blade pitch angles, and wing pitch angles to counteract these forces to perform a successful vertical to horizontal flight transition.

Page updated

Google Sites

Report abuse