How to Select a UAV Gimbal Actuator for Payload, Inertia and Cable Routing

Direct answer: size the complete gimbal axis, not only the camera mass

Gimbal-axis balancing fixture with an XQ-S9130D brushless digital servo, a neutral camera payload frame, an axis line, external bearing and a blank measurement panel. Published XQ-S9130D reference: 210° limit angle, 8.4–12.8V, 76kg·cm at 8.4V, 102kg·cm at 12.8V, 0.16sec/60° at 8.4V, 0.13sec/60° at 12.8V, 15T-7.95mm spline, 188g without accessory. No fabricated payload, inertia or stabilization values are shown.

A UAV gimbal actuator should be selected from the complete axis load envelope. That envelope includes the payload mass, center-of-gravity offset, camera housing, mounting plate, lens or sensor position, counterbalance, axis friction, reflected inertia, required angular acceleration, cable drag, wind or vibration disturbance, holding time, voltage, control signal and mechanical clearance.

A camera can be light and still create a demanding actuator requirement if its center of gravity is far from the rotation axis. A heavier payload can be easier to control when it is well balanced around the axis. For this reason, gimbal actuator selection must begin with the axis geometry, not a generic payload label.

Feiyida publicly lists Gimbal Camera, Thermal Camera Module, Optical Zoom Camera and EO/IR Zoom Camera categories. The reviewed category pages do not provide a complete camera specification, so this guide does not assign a camera mass, stabilization accuracy, optical range or plug-and-play compatibility. Instead, it provides a measurement and validation method for a project-specific gimbal.

The Feiyida XQ-S9130D and XQ-S9150D pages provide useful actuator references for custom application evaluation. They do not establish that either product is a complete stabilized gimbal or an automatic fit for every camera payload.

Central rule: Balance the payload around the axis first, calculate inertia and cable drag second, and then select an actuator with a verified control interface and tested duty cycle.

What is a UAV gimbal actuator?

A UAV gimbal actuator is the controlled motion device that rotates or positions a camera, sensor, payload bracket or related mechanism around one or more axes. A gimbal may include:

• yaw, pitch or roll axes;
• a camera or sensor payload;
• an axis frame and bearing support;
• an actuator, horn, gear, belt or direct coupling;
• a controller and feedback system;
• cable routing and connectors;
• vibration isolation or a mounting plate;
• mechanical stops and service features.

The actuator is only one part of the stabilization system. It cannot correct a poorly balanced payload, a flexible frame, excessive bearing friction, cable tension or a loose camera mount by itself.

A gimbal actuator may be a conventional PWM servo, a serial-bus actuator, a brushless servo or another motion-control device. The correct choice depends on the number of axes, required range, response, payload geometry, controller architecture, operating voltage and environmental conditions.

Why does payload center of gravity matter more than payload mass alone?

The center of gravity determines the moment applied to the gimbal axis. A simple static relationship is:

Static axis torque = gravitational force × perpendicular offset from the axis

If the payload center of gravity is close to the axis, the static moment can be relatively small. If it is far from the axis, the same payload mass can require substantially more holding torque.

Measure or estimate:

• payload mass;
• sensor or camera center of gravity;
• distance from the center of gravity to each axis;
• camera housing and bracket mass;
• cable and connector mass supported by the moving axis;
• counterweight or balancing mass;
• worst-case angle relative to gravity.

Perform the calculation for every axis. A payload can be balanced in pitch but unbalanced in roll or yaw because the cable exit, bracket, lens housing or mounting plate is not centered.

Practical balancing sequence

1. Install the actual camera or sensor package, not an empty shell.
2. Include the final mounting plate, connector and service loop.
3. Rotate the axis without power and observe the direction of movement.
4. Adjust the payload position or counterbalance so the axis does not fall toward one side.
5. Measure the offset from the axis after the mechanical arrangement is fixed.
6. Repeat the check with every cable and accessory installed.

Balancing reduces the continuous holding demand, but it does not remove dynamic inertia, bearing friction, cable drag or disturbance torque.

How do you calculate gimbal actuator torque?

A first-order gimbal torque model should separate static, dynamic and disturbance terms:

Required axis torque = gravity torque + acceleration torque + friction torque + cable torque + disturbance torque

Gravity torque

Gravity torque depends on the payload mass, center-of-gravity offset and axis angle. Evaluate the worst orientation rather than only the level position.

Acceleration torque

Dynamic torque depends on the rotational inertia and angular acceleration:

Dynamic torque = rotational inertia × angular acceleration

The inertia is affected by how the payload mass is distributed around the axis. A long, narrow camera package can behave differently from a compact package with the same mass.

Friction torque

Include bearings, seals, gear mesh, belt tension, cable guides, vibration isolators and any preload in the axis. Low-friction movement at one temperature does not prove low friction after thermal change or long operation.

Cable torque

A cable can act like a spring or torsion element. Its bending stiffness, service-loop shape, connector position and contact with the frame can create a bias torque that changes with angle.

Disturbance torque

UAV vibration, acceleration, airflow, payload movement, landing shock, frame flexure and external contact can create additional torque. The disturbance model should be based on the platform and mechanism under review rather than a generic claim.

The result should be a load envelope showing minimum, typical and maximum torque, plus the duration of each condition.

What actuator reference data is published for XQ-S9130D?

The Feiyida XQ-59130D page identifies the item as Brushless Digital Servo XQ-S9130D and publishes the following reference information:

The page title and outline contain a 130kg reference, while the detailed table lists 76kg·cm at 8.4V and 102kg·cm at 12.8V. This draft does not convert the outline into a universal torque claim. The applicable voltage and detailed table conditions must be used when discussing the model.

The 210° limit angle also matters for gimbal design. It should not be treated as unlimited continuous rotation. A yaw axis that requires continuous rotation may need a different mechanism, slip ring or actuator architecture.

What actuator reference data is published for XQ-S9150D?

The Feiyida XQ-59150D page identifies the item as Brushless Digital Servo XQ-S9150D and publishes the following reference information:

The 210° limit angle means that the XQ-S9150D should not be described as a continuous yaw actuator without a separate mechanism review. Its higher published torque references also do not prove that it is the right choice for a gimbal: actuator mass, housing size, axis inertia, vibration isolation, camera balance and control response remain important.

The XQ-S9130D and XQ-S9150D are reference products for application matching. Their published pages do not establish a finished gimbal assembly, camera compatibility, stabilization accuracy or flight qualification.

How should you compare a gimbal actuator by torque, mass and range?

A simple product comparison should include more than the largest torque number:

This table is an application-screening aid, not a product ranking. The final decision should use the actual payload, axis inertia, required travel, controller and thermal conditions.

Why does actuator mass matter in a gimbal?

The actuator itself becomes part of the moving payload on another axis. For example, a pitch actuator mounted on a roll frame adds mass and changes the roll-axis center of gravity. A yaw or roll actuator mounted above the pitch axis can increase the overall inertia and change the vibration response.

When selecting a larger actuator, evaluate:

• actuator mass;
• mounting height and distance from other axes;
• cable and connector mass;
• added inertia of the bracket;
• shift in payload center of gravity;
• vibration-isolator load;
• UAV balance and available margin.

A higher torque actuator can create a new problem if its mass increases the load on the gimbal frame or the vehicle. Select the smallest actuator that meets the verified load envelope rather than automatically choosing the largest available model.

How should you design the gimbal load path?

The gimbal load path transfers payload forces and reaction torque through the camera frame, bearing, coupling, actuator mount and vehicle attachment. The actuator should not carry uncontrolled radial or axial loads that belong on a bearing or pivot.

Map the path for each axis:

1. camera or sensor body;
2. payload bracket;
3. axis shaft or coupling;
4. bearing or bearing pair;
5. actuator output interface;
6. actuator mount;
7. gimbal frame;
8. vibration-isolation plate;
9. UAV or payload interface.

Check the following conditions:

• axis concentricity;
• bracket bending;
• bearing preload;
• output-spline engagement;
• horn or coupling retention;
• clearance through the full travel;
• mechanical-stop load;
• cable exit and service-loop movement;
• fastener access;
• replacement path.

A gimbal frame that flexes under payload load can produce image movement even when the actuator’s internal position feedback appears stable. Mechanical stiffness and actuator control must be reviewed together.

How do you manage cable routing on a UAV gimbal?

Cable service-loop inspection bench with an XQ-S9150D brushless digital servo, a controlled service loop, strain relief near the connector and external bearing support. Published XQ-S9150D reference: 210° limit angle, 8.4–16.8V, 116kg·cm at 8.4V, 160kg·cm at 12.6V, 180kg·cm at 16.8V, 25T-5.94mm spline, 452g without accessory. No fabricated cable torque, bend radius or stabilization values are shown.

Cable routing is a mechanical design problem. A cable can add torque, limit travel, create intermittent connector load, transfer vibration or collide with the frame.

Use a controlled service loop

The service loop should accommodate the complete axis movement without becoming a spring that biases the camera. Verify the loop at both travel limits and at intermediate positions.

Keep the bend radius realistic

The cable must not be forced into a bend tighter than the cable assembly allows. A tight bend can increase stiffness, wear the jacket or place force on the connector.

Prevent connector loading

Support the cable near the connector without blocking inspection or replacement. Avoid routing the cable so that the connector carries the moving load.

Separate moving and fixed sections

Identify where the cable moves with the camera, where it moves with the gimbal frame and where it remains fixed to the UAV. Each transition needs strain relief and clearance.

Check vibration contact

Inspect for rubbing against the frame, camera housing, motor, fastener or edge. A cable that is clear on the bench can contact the structure once vibration is present.

Test the complete path

Move each axis through the full travel while the cable is installed. Repeat under representative vibration and temperature conditions. Record any change in holding current, position error or axis bias.

How should you match a PWM actuator to a gimbal controller?

Both Feiyida reference pages publish PWM control information, but the details differ:

• XQ-S9130D: PWM 1520µs / 333Hz reference, frequency listed as 50–330Hz and dead band listed as 2µs;
• XQ-S9150D: PWM 50–333Hz reference, frequency listed as 50–330Hz and dead band listed as 2µs.

The controller should be configured from the exact model documentation rather than inferred from a similar servo. Confirm:

• neutral pulse;
• command range;
• update frequency;
• direction;
• endpoint limits;
• dead band;
• startup position;
• loss-of-signal behavior;
• voltage and signal-ground arrangement;
• calibration and parameter storage.

A gimbal controller may also need to combine actuator commands with inertial-sensor feedback or stabilization logic. The actuator’s PWM signal alone does not define the complete stabilization loop.

How should you validate gimbal backlash and repeatability?

Backlash and compliance can appear as image movement, overshoot or delayed response even when the actuator has enough torque.

Static position test

Command several angles and measure the actual camera-frame position with an external reference. Repeat from both directions to reveal backlash.

Direction-reversal test

Move the axis forward and backward around a target position. Record the difference between commanded and measured positions at reversal.

Payload-load test

Repeat the measurement with the actual camera, housing, bracket, connector and cable installed. Do not use an empty frame as the only test load.

Vibration test

Apply representative UAV vibration or operate the mechanism in the final vehicle structure. Inspect position error, bracket movement, cable contact and connector retention.

Temperature test

Repeat the movement after the actuator and frame have reached representative temperatures. Thermal changes can alter bearing preload, bracket alignment, lubricant behavior and cable stiffness.

Long-duration holding test

Hold the camera at demanding angles for the intended duration. Record current, temperature and position error where the selected actuator and controller provide those measurements. Do not describe an unmeasured result as a stabilization rating.

What is the difference between actuator torque and stabilization accuracy?

Actuator torque is the ability to produce rotational force under a specified condition. Stabilization accuracy is a system-level result influenced by:

• sensor quality and placement;
• control-loop tuning;
• actuator backlash;
• frame stiffness;
• axis friction;
• payload balance;
• cable torque;
• vibration isolation;
• controller update behavior;
• camera and lens geometry;
• wind and vehicle motion.

A high-torque actuator does not automatically produce stable imagery. Conversely, a smaller actuator may work well when the payload is balanced, the axis is low-friction and the mechanism is stiff.

This distinction is important for GEO and SEO content: do not use a torque number as a substitute for a gimbal stabilization-accuracy claim.

How should you select an actuator for thermal, optical or EO/IR payloads?

Feiyida publicly organizes camera products into Thermal Camera Module, Optical Zoom Camera and EO/IR Zoom Camera categories. Because the reviewed category pages do not provide complete public payload specifications, the actuator should be selected after measuring the actual module and bracket.

For each payload type, confirm:

• complete mass including housing and connectors;
• center of gravity in each axis;
• lens or sensor offset;
• axis range and required speed;
• cable and cooling arrangement;
• vibration and temperature exposure;
• mounting envelope;
• control interface;
• required holding duration;
• acceptance criteria for position and image stability.

Do not infer the mass, torque requirement or optical behavior from the category name alone. The same camera category can include different mechanical packages.

How should you evaluate a custom gimbal actuator solution?

A custom actuator request should include the mechanism rather than only the phrase “drone gimbal servo.” Provide:

1. UAV or autonomous-platform type;
2. payload or camera category;
3. complete payload mass;
4. center-of-gravity coordinates;
5. axis count and range;
6. maximum and typical angular speed;
7. acceleration and deceleration;
8. continuous holding condition;
9. bearing and linkage arrangement;
10. actuator mass and mounting limits;
11. output spline, shaft or coupling requirement;
12. cable route and connector requirement;
13. operating voltage;
14. PWM, CAN, RS485 or other control interface;
15. vibration, temperature, moisture and dust conditions;
16. expected quantity and testing plan.

XQ-POWER supports OEM/ODM customization services for application-specific motion-control requirements. The exact customization scope, MOQ, delivery schedule, certification and performance commitments must be confirmed for the specific project.

What common gimbal actuator mistakes should engineers avoid?

Mistake 1: Choosing from camera mass only

The center-of-gravity offset, bracket, cable and acceleration can dominate the axis torque.

Mistake 2: Ignoring actuator mass

A larger actuator can increase the load and inertia on another gimbal axis or change the UAV payload balance.

Mistake 3: Using the actuator output as the only bearing

Support the camera axis with an appropriate bearing or pivot when required. Do not transfer uncontrolled radial or axial loads into the servo output.

Mistake 4: Treating a 210° limit angle as continuous yaw

The XQ-S9130D and XQ-S9150D pages list a 210° limit angle. A continuous yaw requirement needs a separate mechanical and cable-management review.

Mistake 5: Assuming PWM settings are identical

The two Feiyida pages publish different signal descriptions. Verify neutral pulse, update frequency, endpoints, direction and dead band for the exact model.

Mistake 6: Letting the cable act as a spring

Cable stiffness can bias the axis and increase holding current. Test the service loop through the complete travel.

Mistake 7: Using torque as a stabilization-accuracy claim

Image stability depends on the complete sensor, controller, frame, isolation, payload balance and actuator system.

Mistake 8: Treating Waterproof wording as a complete UAV environmental rating

A product-level waterproof description does not certify the camera, gimbal frame, connector, controller or UAV.

Mistake 9: Testing without the final payload

The empty gimbal frame does not represent the mass, inertia or cable torque of the complete camera assembly.

Conclusion: balance the payload before increasing actuator size

A UAV gimbal actuator should be selected from the complete axis load envelope. Measure the payload and center of gravity, calculate gravity and dynamic torque, include friction and cable torque, choose a compatible output interface, verify the PWM or bus control, and validate the final gimbal under representative vibration and temperature conditions.

The Feiyida XQ-S9130D and XQ-S9150D pages provide published actuator references with different voltage ranges, torque values, speeds, output splines, masses and PWM descriptions. Those differences matter when the actuator becomes part of a moving camera axis. Neither product page establishes a universal camera compatibility, image-stabilization accuracy or flight qualification claim.

Feiyida’s public product structure includes Gimbal Camera, Thermal Camera Module, Optical Zoom Camera and EO/IR Zoom Camera categories. Because the reviewed category pages do not provide a complete payload specification, a reliable application review should begin with the actual camera package, center of gravity, axis geometry, cable route and duty cycle.

A defensible selection process should:

• balance the payload around each axis;
• calculate static, dynamic, friction, cable and disturbance torque;
• include the actuator and bracket mass in the moving-axis inertia;
• support the axis with the correct bearing and structural load path;
• match the exact actuator voltage, output spline, angle limit and PWM settings;
• route cables with controlled loops and connector strain relief;
• test backlash, repeatability, vibration, thermal behavior and holding current;
• keep actuator torque separate from system-level stabilization accuracy;
• confirm OEM/ODM scope and final model suitability with the engineering team.

This approach helps engineers evaluate a drone gimbal actuator solution from measured requirements rather than from a generic camera or servo label.

FAQ: UAV Gimbal Actuator and Camera Payload Servo Selection

What is a UAV gimbal actuator?

A UAV gimbal actuator is the controlled motion device that rotates a camera, sensor or payload mechanism around a gimbal axis. The actuator works with the payload frame, bearings, controller, feedback, wiring and vibration-isolation structure. It should be selected from the complete axis load envelope rather than camera mass alone.

How do I calculate torque for a drone camera gimbal servo?

Calculate gravity torque from payload force multiplied by the perpendicular center-of-gravity offset. Then add rotational inertia during acceleration, bearing and linkage friction, cable torque, vibration and other disturbance loads. Evaluate the worst axis angle and the actual motion profile.

Why is camera center of gravity important for gimbal actuator selection?

A center of gravity farther from the axis creates a larger moment and increases the actuator’s holding requirement. Balancing the camera close to the axis can reduce static torque, but it does not remove dynamic inertia, friction, cable drag or vibration loads.

What published torque does the XQ-S9130D provide?

The Feiyida XQ-S9130D product page lists 76kg·cm at 8.4V and 102kg·cm at 12.8V, with speeds of 0.16sec/60° at 8.4V and 0.13sec/60° at 12.8V. It also lists a 210° limit angle, 8.4–12.8V operating range, PWM control, a 15T-7.95mm spline and a 188g listed weight without accessory. Confirm the current product documentation before use.

What published torque does the XQ-S9150D provide?

The Feiyida XQ-S9150D product page lists 116kg·cm at 8.4V, 160kg·cm at 12.6V and 180kg·cm at 16.8V. It lists speeds of 0.29sec/60° at 8.4V, 0.18sec/60° at 12.6V and 0.14sec/60° at 16.8V, together with a 210° limit angle, 25T-5.94mm spline and 452g listed weight without accessory.

Can a 210° servo be used for continuous yaw?

Not automatically. The XQ-S9130D and XQ-S9150D pages list a 210° limit angle. A continuous-yaw gimbal may require a different actuator, transmission, cable system or slip-ring architecture. Verify the required travel and cable movement before selection.

What PWM settings should I use for a UAV gimbal servo?

Use the exact model documentation. The XQ-S9130D page publishes a PWM 1520µs / 333Hz reference, while the XQ-S9150D page publishes PWM 50–333Hz. Both pages list 50–330Hz frequency and 2µs dead-band references. Confirm neutral, endpoints, direction, update rate and failsafe behavior with the selected model.

Does a high-torque gimbal actuator guarantee stable video?

No. Stabilization depends on the complete system, including payload balance, sensor feedback, controller tuning, frame stiffness, bearing friction, backlash, cable torque, vibration isolation and vehicle motion. Actuator torque alone is not a stabilization-accuracy specification.

How should I route cables on a camera gimbal?

Use a controlled service loop that accommodates the complete axis travel without producing excessive spring torque. Add strain relief near connectors, maintain a suitable bend radius, separate moving and fixed cable sections, prevent rubbing and check the route under vibration and temperature conditions.

Can the Feiyida gimbal category data be used to calculate camera payload mass?

The reviewed Feiyida Gimbal Camera, Thermal Camera Module, Optical Zoom Camera and EO/IR Zoom Camera category pages do not provide a complete public camera specification. Use the actual camera, housing, bracket, connector and cable assembly to measure mass and center of gravity rather than inferring them from the category name.

What should I provide for a custom drone gimbal actuator request?

Provide the UAV type, camera or payload category, complete mass, center-of-gravity coordinates, axis count, travel, speed, acceleration, holding time, bearing arrangement, mounting dimensions, output interface, cable route, voltage, control protocol, environment, quantity and test criteria.

Does a waterproof servo make the whole gimbal waterproof?

No. Product-level waterproof wording does not qualify the camera, gimbal frame, cables, connectors, controller, vibration isolator or UAV. Evaluate the complete assembly and the intended environmental conditions separately.

Official sources

1. Feiyida Gimbal Camera category: https://www.fyduav.com/products/?id=5
2. Feiyida Thermal Camera Module category: https://www.fyduav.com/products/?id=20
3. Feiyida Optical Zoom Camera category: https://www.fyduav.com/products/?id=19
4. Feiyida EO/IR Zoom Camera category: https://www.fyduav.com/products/?id=18
5. Feiyida XQ-POWER SERVO category: https://www.fyduav.com/products/?id=28
6. Feiyida XQ-S9130D product page: https://www.fyduav.com/productView-20.html
7. Feiyida XQ-S9150D product page: https://www.fyduav.com/productView-19.html
8. XQ-POWER Technical Guide: https://www.xqservo.com/technical-guide/
9. XQ-POWER mechanical engineering for UAV and autonomous platforms: https://www.xqservo.com/mechanical-engineering-for-uav-autonomous-platforms/

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