Drone gimbal motors drive cameras or electro-optical equipment along different motion axes. They adjust the camera angle according to feedback from attitude sensors, compensating for vibration and changes in the UAV's orientation during flight. Brushless DC motors (BLDC) are among the most widely used drive solutions for drone gimbals. Stepper motors and coreless motors may also be used in specialized positioning mechanisms or miniature gimbal designs.
Different motor types have different characteristics in terms of output torque, dynamic response, positioning accuracy, structural dimensions, and operating smoothness. The appropriate motor depends on the gimbal payload, motion range, response requirements, and available installation space.
Common Motor Types Used in Drone Gimbals
Brushless DC Motors (BLDC)
Brushless DC motors are one of the most common drive solutions for drone gimbals, particularly in stabilization systems that require continuous attitude compensation and rapid angular adjustments.
Unlike conventional brushed motors, BLDC motors use electronic commutation to control current in the stator windings. They do not require mechanical brushes or a commutator. Many gimbal designs use direct-drive configurations, in which the motor directly rotates the camera around its mounting axis. This reduces backlash and mechanical friction associated with gear transmission.
Their main characteristics include:
Smooth operation: Appropriate pole configurations, winding designs, and current control methods can reduce cogging torque and torque ripple, improving smoothness during low-speed operation.
Fast dynamic response: When combined with a servo controller and attitude sensors, the motor can adjust the camera angle quickly in response to UAV movement, vibration, and external disturbances.
Long service life: The absence of mechanical brushes eliminates brush wear and reduces associated maintenance requirements.
Direct-drive capability: The motor can be mounted directly on the gimbal axis to drive the camera or sensor assembly, reducing errors introduced by intermediate transmission components.
In practical applications, gimbal BLDC motors require compatible motor controllers. Some systems use Field-Oriented Control (FOC) together with encoder feedback to achieve closed-loop position control, improving low-speed smoothness and angular positioning performance.
Stepper Motors
Stepper motors are used in some gimbals and associated actuators that require specific angular positioning or repeated scanning movements. The controller sends pulse signals to rotate the motor by a specified number of steps and in a defined direction.
Their main characteristics include:
Convenient positioning control: The rotation angle can be controlled by adjusting the number of input pulses, making stepper motors suitable for preset position changes and repetitive positioning tasks.
High holding torque: Stepper motors can provide relatively high holding torque at low speeds or when stationary, which is useful for mechanisms that need to maintain a specific position.
Relatively simple control structure: Open-loop control can be used in applications that do not require complex position feedback.
The main limitations of stepper motors are their dynamic response and operating smoothness. During rapid changes in UAV attitude, open-loop control can be affected by variations in load and may result in missed steps. Compared with this arrangement, BLDC motors equipped with encoders and closed-loop control are generally more suitable for camera stabilization systems requiring fast and continuous attitude compensation.
Stepper motors are therefore more commonly considered for gimbals with specific positioning requirements or auxiliary actuators rather than as the default drive solution for all drone stabilization systems.
Coreless Motors
Coreless motors use a rotor without a conventional iron core. Some miniature gimbals and lightweight actuating mechanisms may use this type of motor, depending on payload and installation space requirements.
The absence of a traditional iron core reduces rotor inertia and can improve response speed. It also reduces iron-related hysteresis losses and some sources of torque pulsation.
Their main characteristics include:
Low rotor inertia: The coreless rotor helps reduce rotor mass and inertia, making it suitable for compact actuators requiring fast response.
Fast response: These motors can meet the requirements of some miniature devices involving rapid starting, stopping, and angular adjustment.
Compact structure: Their small dimensions make them suitable for miniature gimbals and other precision motion mechanisms with strict weight and installation space limitations.
It is important to distinguish coreless motors from brushless DC motors. Common coreless DC motors use brushes for commutation, although brushless motor designs without iron cores are also available. Since output torque is generally limited by motor dimensions, their suitability as the main gimbal drive must be evaluated according to payload, operating duration, and temperature rise.
Key Performance Parameters of Drone Gimbal Motors
In addition to motor type, selection requires attention to continuous torque, peak torque, angular positioning accuracy, and dynamic response.
Continuous Torque and Peak Torque
Continuous torque refers to the torque a motor can deliver over an extended period under specified temperature and operating conditions. Peak torque is the maximum output torque available for a specified period.
The original reference material gives the following 2024-era reference values for some drone gimbal BLDC motors: continuous torque of 0.1 to 0.5 N·m and peak torque exceeding 1 N·m. These values depend on motor dimensions, supply voltage, winding configuration, and cooling conditions. They should not be treated as universal specifications for all drone gimbal motors.
Angular Positioning Accuracy
Gimbal motors must adjust camera angles according to control commands, making position control and angular feedback important performance factors. Some systems can achieve angular stabilization or positioning errors within ±0.01°.
Actual angular accuracy depends not only on the motor but also on encoder resolution, control algorithms, mechanical assembly errors, and load variations. During selection, angular stabilization accuracy, repeat positioning accuracy, and speed control accuracy must be distinguished. These parameters are not interchangeable.
Dynamic Response
When a UAV encounters airflow disturbances or changes its flight attitude, the gimbal motor must adjust its output torque quickly to maintain a stable camera pointing direction. Dynamic response depends on rotor inertia, output torque, controller performance, and the feedback rate of attitude sensors.
For gimbals that require continuous stabilization, motor response speed is only one consideration. Low-speed torque smoothness, cogging torque, and the response characteristics of the control system must also be evaluated.
Motor Selection Recommendations for Drone Gimbals
Different applications place different demands on gimbal motors. Selection should take into account camera weight, gimbal structure, motion range, and flight conditions.
Standard aerial photography gimbals: Low-cogging brushless DC motors with smooth low-speed operation are generally preferred. The required torque should be determined according to camera weight and center of gravity.
Industrial positioning and scanning gimbals: For equipment requiring repeated positioning at preset angles, stepper motors or encoder-equipped brushless servo motors can be evaluated according to positioning accuracy and dynamic response requirements.
Miniature and lightweight gimbals: Miniature coreless motors or small brushless motors can be considered according to installation space, payload, and power consumption requirements.
In addition to motor type, check the motor mounting dimensions, shaft diameter, mounting hole positions, encoder interfaces, driver compatibility, and cooling conditions. The motor must be compatible with both the gimbal's mechanical structure and its control system.
Custom Machining of Precision Parts for Drone Gimbals
The motor mounting and transmission structures of drone gimbals include motor mounting bases, shafts, bearing brackets, connecting plates, and other precision mechanical components. Their dimensional accuracy, mounting fits, and structural stiffness affect motor operation and overall gimbal stability.
Hansheng Automation provides custom precision machining based on customer drawings and accepts both single-piece and small-batch orders. In addition to structural components for drone gimbals, our machining services also cover precision parts for yachts and RC racing cars, as well as components for tobacco packaging machinery and filling equipment. Parts are manufactured according to the drawings and assembly requirements of each project.
