How to Synchronize Four Linear Actuators Guide: Wiring Setup

You need 4 linear actuators to lift a roof, platform, hatch, or cover without twisting the frame. Use 4 matching actuators, a controller that compares feedback from each actuator, rigid mounts, equal wiring runs, and enough force margin for the worst-loaded corner. For FIRGELLI systems, the FCB-2 remote actuator controller can synchronize 2, 3, or 4 actuators.

What is four-actuator synchronization?

Four-actuator synchronization keeps 4 electric linear actuators at the same travel position during extension and retraction. The controller watches each actuator and corrects motion so the lift stays level instead of racking.

Simple Explanation

Think of a wide campervan roof like a table with 4 powered legs. If 1 leg moves 0.5 inches ahead of the others, the top twists and the guides fight the actuators.

Feedback synchronization gives the controller a way to see that error and correct it while the lift moves. Matching part numbers helps, but matching alone does not guarantee synchronized travel under uneven load.

How should you read the synchronized roof lift visualizer?

The visualizer below shows the problem faster than a paragraph can. The left side shows mismatched actuator travel twisting a campervan roof, while the right side shows a feedback controller keeping the lift level.

Watch the roof angle, actuator rods, and control signal paths. The takeaway: 4 actuators need position correction when the structure cannot tolerate corner-to-corner height error.

When do you need 4-actuator synchronization?

You need it when a wide or flexible structure needs 4 lift points and the frame cannot tolerate skew. A campervan pop-top, machine guard, RV slide-out cover, or wide inspection hatch can bind when 1 corner outruns another.

You also need it when the load shifts. People climb into campervan beds, tool trays slide inside machine enclosures, and wind loads push outdoor covers. The actuator at the heavy corner slows first, and the light corner runs ahead unless the controller corrects position.

How does 4-actuator synchronization work?

A synchronized system uses 4 actuators, 4 controlled motor outputs, and a position signal from each actuator when the control strategy requires feedback. The controller compares travel and adjusts each actuator so all corners reach the same position together.

1. Each actuator starts from a known calibrated position.
2. The controller drives all 4 motor channels in the same direction.
3. Each actuator sends a position-related signal back to the controller.
4. The controller slows, stops, or corrects any actuator that gets ahead.
5. The system stops at the programmed end point or physical limit, depending on the control setup.

Hall sensors read alternating magnetic poles on a rotating disk inside the gearbox. Optical sensors read light pulses through slots in a rotating disk. Neither device measures direct rod travel; the controller infers travel from gearbox or encoder-disc movement after calibration.

Controllers usually treat Hall and optical feedback as pulse signals. Compatibility depends on voltage, wiring, pulse type, pulse count, direction handling, and calibration. That detail matters more than the label on the actuator.

What controller do you need for 4 actuators?

Use a controller that can manage 4 actuator channels, read the feedback signals you selected, and calibrate travel across all 4 devices. A simple polarity-reversing switch starts motors together, but it does not correct position drift after the lift begins moving.

The FCB-2 remote actuator controller can synchronize 2, 3, or 4 actuators, and you can also use it with non-feedback actuators where the control setup calls for it. That makes it the control box to consider when your project grows beyond a simple 2-actuator lift.

For setup details, read the FIRGELLI FCB-2 linear actuator controller guide. Use the FCB setup and video guides during commissioning. The FCB-1 non-remote control box guide covers the non-remote control box version.

How should you balance the load across 4 actuators?

Do not divide total weight by 4 and stop. That shortcut only works when the center of gravity sits in the middle, all 4 guide rails slide freely, and all 4 actuator angles match.

The formula above gives a starting force per actuator. Then check the worst-loaded corner. If a 320 lb roof puts 40% of its weight on 1 corner, that actuator sees 128 lb before friction. With a 1.5 safety factor and a 1.2 guide factor, that corner needs 128 × 1.5 × 1.2 = 230 lb of force.

That 1-corner check often drives the actuator choice. A system can look safe at 144 lb per actuator on average and still overload 1 corner when the center of gravity shifts.

How should you wire 4 synchronized actuators?

Run every actuator motor lead and feedback lead back to the controller. Do not daisy-chain feedback lines, tie pulse wires together, or let 1 actuator share a return path that adds voltage drop to another channel.

Keep cable lengths similar where practical, protect the wiring from pinch points, and size the power supply for the combined current draw from all 4 actuators. Use the linear actuator wiring diagram generator before you cut wire, because actuator count, power, switches, feedback, and accessories all affect controller selection.

If you want a broader control-system view, compare options in Linear Actuator Control Boxes: Channels, Synchronization, Remotes, and Wiring. If you need a basic actuator family overview before control selection, start with linear actuators and feedback linear actuators.

What formula checks skew before the lift binds?

Use this quick skew check when the lift uses rails, slides, or 4 corner posts. Small height errors create a surprisingly large side load when the frame has tight clearances.

α ≈ atan(Δh ÷ B)

Example: if 1 side of a roof runs 0.5 inches high across a 72-inch width, α ≈ atan(0.5 ÷ 72) = 0.40°. That looks tiny on paper, but it can shove guide rails sideways and bend brackets during a long stroke.

What are the trade-offs between 4-actuator control methods?

Suitable Applications

Four-actuator synchronization makes sense when the moving part spans enough width or length that 2 lift points cannot control twist. The application usually tells you whether you need feedback, long stroke, higher force, or better environmental protection.

Related FIRGELLI Products

Use the product data below as a starting point, then confirm force, stroke, speed, IP rating, feedback, bracket geometry, and controller compatibility against your actual layout. The linear actuator selector and linear actuator calculator can help before you order parts.

Mounting makes or breaks synchronized lifts. Utility actuator installations can use the MB1-P Mounting Bracket for P-series Actuator at the base end and the MB1 Bracket at the rod end. Super Duty installations can use the MB17 Mounting Bracket For Super Duty Actuators for clevis or end mounting.

For controls beyond synchronization, compare actuator controls. If you want background reading on similar projects, see How to Synchronize Two Linear Actuators Guide: Sync Setup and How to Synchronize up to 4 Electric Linear Actuators.

FAQ

Can you run 4 linear actuators from 1 switch?

You can power 4 actuators from 1 switch only when the application tolerates drift. A switch reverses polarity and starts the motors, but it does not measure position. If the frame needs level travel, use a synchronization controller and actuators that match the control method.

Do all 4 actuators need feedback to synchronize?

True position synchronization needs position information from each actuator or a control method that can correct travel error. Matched non-feedback actuators can still drift under unequal loads. The FCB-2 can also work with non-feedback actuators where the control setup calls for that approach.

Can FCB-2 synchronize 4 linear actuators?

Yes. The FCB-2 remote actuator controller can synchronize 2, 3, or 4 actuators. Check actuator compatibility, wiring, power supply sizing, and calibration before you build the final harness. Use the wiring diagram generator when you combine multiple actuators, switches, feedback lines, and accessories.

What happens if 1 actuator moves faster than the others?

The structure racks. That means the fast corner rises or retracts ahead of the slower corners, which creates side load in guides, brackets, pivots, or hinges. Common results include noisy travel, blown fuses, stalled actuators, bent mounts, and a lift that jams halfway through the stroke.

Do Hall effect and optical feedback measure rod position directly?

No. Hall sensors read alternating magnetic poles on a rotating disk, and optical sensors read light pulses through slots in a rotating disk. The controller counts those pulses and infers actuator travel after calibration. Neither signal measures force, side load, or mechanical binding.

How much force should each actuator have in a 4-actuator lift?

Start with F_actuator = (W × SF × G) ÷ 4 for a vertical guided lift. Then check the worst-loaded corner. For most DIY lifts, use at least a 1.5 safety factor and add margin for friction, misalignment, wind load, and accessories.

What should you check before you power 4 actuators?

• Use 4 matching actuators with the same stroke, force rating, voltage, speed family, and feedback type.
• Confirm the worst-corner load, not just the average load.
• Keep actuator centerlines parallel through the full stroke.
• Use rigid mounts and correct brackets for the actuator series.
• Run motor and feedback wiring back to the controller without shared feedback lines.
• Calibrate the controller before loading the mechanism fully.
• Test the lift in short movements and watch for skew, noise, current spikes, and guide binding.

About the Author

Robbie Dickson is the Chief Engineer and Founder of FIRGELLI Automations. With a background in aeronautical and mechanical engineering at Rolls-Royce, BMW, and Ford, he has spent over 2 decades developing precision motion control systems, from linear actuators for robotics to active aerodynamic braking systems for supercars. For a 4-actuator lift, check force, stroke, feedback, wiring, mounts, and corner load before you drill holes.