Mature brushless motor and control technology help UAV to develop a larger market

 Air traffic control requires that the lift of UAVs be limited to 120 m, above ground height and must remain within the sight of the user. Most consumer-class drones can only fly for 20-25 minutes, flying around 2 kilometers, and drones can become successful products only if they bring consumers a pleasant flight experience.

 Consumer UAVs generally have four rotors with four separate motors, each with a drive propeller, which must be integrated with power (battery), control microelectronic equipment and software, aircraft sensors (such as accelerometers) and payloads. The consumer UAV design focuses on high portability, ease of use and flight, while providing better imaging / video quality, with 4 K of video and high dynamic range (HDR) images as well as features such as collision sensors.

Why use a four-rotor configuration for vertical take-off and landing (VTOL) drones? The vertical take-off and landing UAV is equipped with four rotor, the four blade rotor is a simple prop, and the blade angle is fixed, which is controlled by the motor at each throttle point. Two rotors rotate clockwise and the other two rotors rotate counterclockwise, thus eliminating the torque effect. Each rotor tilts at an angle, the rotor throttle points together increase or decrease lift, the aircraft rises or drops, and the control current realizes the pitch, yaw and roll of the UAV. Some of the more expensive drones are designed with hexagonal rotors that can fly continuously even if a rotor fails.

 The UAV needs to maximize the lift capacity. The thrust and efficient output of the motor and prop will not only affect the flight, but also affect the stability and control ability of the UAV. UAVs can not use helicopters with large and tail rotors to eliminate torque. Helicopter rotors are complex and each blade needs to change its angle of attack in the air. The mechanical disc changes the blade angle in different ways and moves along the direction you want, and the mechanical disc changes the blade angle to increase the weight of the part.

The UAV plays an important role in converting electric energy into mechanical power. The motor has high output power and the best efficiency in hovering. The motor sets a critical weight range to make the UAV as light as possible, thus increasing durability and overall portability. The UAV adopts brushless motor to switch or switch the current (and the resulting magnetic field) in the armature coil electronically, thus generating torque through the reaction to the permanent magnet magnetic field. the outer ring of the magnet leads to a larger air-gap surface area to allow the electromagnetic field to pass through the rotating shaft with a larger radius, and the extension device inherently produces greater torque. With the increase of winding coil automation, the cost of small brushless motor is greatly reduced. The use of shape memory materials avoids the complexity of mechanical components, makes propeller increase the degree of freedom to raise height, and improves the controllability and stability of UAV.

Brushless motor has higher dustproof and moisture-proof performance, winding wire is isolated, no contact in sensitive area, efficiency is one of the key performance indexes of motor. The motor is accurately adapted to the propeller to provide good heat dissipation, which is why the winding is particularly important, and the coil must be kept cool, thus maximizing the motor efficiency. Brushless motors are more durable than brushless motors, with less friction at tens of thousands of revolutions per minute (rpm), reducing contact wear. No brush reduces the arc, which may cause electromagnetic interference, which affects the electronic equipment of UAV. At the same time, the seal design scheme of UAV can further improve the normal operation time of UAV.

The motor control algorithm is customized to hover and push the UAV at the highest speed, and the motor enhances the flight stability by fast response time in each flight stage. The electromagnetic, mechanical and electrical properties of the motor selected by the UAV are strictly required to minimize its size and weight. With the maturity of brushless technology, the ultimate goal is to reduce the size and weight while ensuring the high performance of the motor.

 The motor controller switches quickly between each controller and the signal issued by the driving motor. The UAV uses a control algorithm to produce a trapezoidal signal with an approximate sine wave to reduce the heat. The controller is placed close to the propeller or uses a single radiator in the airflow below the propeller tip. The weight of the radiator is minimized and relative to the center of gravity, minimizing the impact on inertia and controllability. The efficient UAV meets the minimum heat consumption power and will consume the battery at a slower speed, thus prolonging the flight time.

 Conclusion

 UAVs flying in extreme temperatures, precipitation, dust and other particles not only affect mechanical and electrical components, but also affect the performance of each subsystem, which is essential for the reliability of UAVs. This requires that the service life of system components (especially motors) is longer than that of ordinary brushless motors. current uav technologies and systems provide general functions to consumers, but industry developments are leading to more and more cost-effective uavs coming into the market in the future.