Small Multi-Rotor UAV Oriented Direct Thrust Sensor Based on Lightweight Barometers

The multirotor unmanned aerial vehicle (UAV) requires precise control over thrust output when operating in wind-disturbed environments or executing intricate flight mis- sions. Although current commercial force sensors offer high sensitivity and accuracy, they are often heavy and costly. These characteristics restrict their applicability in weight-sensitive and cost-sensitive scenarios, such as thrust measurement in UAVs. To overcome this difficulty, we have developed an em- bedded barometric force sensor (BFS) that mounts between the UAV’s airframe and motor, allowing direct measurement of the force exerted by the rotor on the UAV’s rigid body. The BFS is designed using low-cost MEMS barometers as tactile force sensors, encased in polyurethane rubber. Subsequently, we established its parameter model and devised a stability im- provement strategy to reduce the impact of temperature. Addi- tionally, we designed a structure suitable for mounting the BFS on the UAV to safeguard the rubber module from damage and reconstructed the thrust model to account for the impact of weight and friction on thrust measurement. Finally, we assem- bled testing platforms to validate the performance of the BFS. Experimental results demonstrate the BFS’s excellent linearity, wide range, adequate bandwidth to respond to UAV thrust variations, and confirm the feasibility of mounting the BFS on the UAV for thrust measurement and force feedback control.