How to Synchronize Two Linear Actuators Guide: Sync Setup

You need 2 actuators to lift the same roof, hatch, or platform without twisting it. Synchronize them by using matched-stroke actuators, position feedback, and a controller that compares pulse counts from each actuator, then corrects travel before the mechanism racks. The controller does the job; matched actuators alone do not under uneven load.

What is linear actuator synchronization?

Linear actuator synchronization means 2 or more actuators move the same distance at the same time while they push the same load.

You need it when 2 actuator rods support 1 rigid panel and a small mismatch can twist the structure.

Simple Explanation

Think of 2 people lifting opposite corners of a campervan roof. If the left side rises 0.5 inches before the right side catches up, the roof tries to turn into a parallelogram.

A synchronized controller watches each actuator and corrects that difference before the guides bind.

What formula checks actuator travel mismatch?

Use the formula below to calculate actuator mismatch from pulse feedback.

Δx = |N₁ − N₂| ÷ PPI

Use PPI for inches or PPMM for millimeters. A tight lift needs a small Δx; a loose gate can tolerate more.

How do you read the visualizer?

Watch the roof line, not just the rods. A skewed roof tells you the actuators no longer share travel equally. The synchronized side keeps both guide rails parallel, which protects brackets and reduces side load on the rods.

Use it as a design check for wide panels. If your mechanism looks like the left side, add feedback, improve guide alignment, or stop trying to drive 2 independent actuators from the same switch.

When do you need to synchronize 2 linear actuators?

You use synchronization when a single actuator would twist the load or when 2 lift points must stay level. A campervan pop-top roof, a wide machine guard, or a dual-actuator hatch all need the same basic control logic.

The exact moment comes during actuator selection. If the load spans across 2 mounting points and the structure cannot flex without damage, choose a feedback actuator and a controller before you drill brackets.

Suitable Applications

These jobs push 2 actuators into the same structure. That shared structure creates the synchronization problem.

Where do synchronized actuator systems show up?

• Robotics lift axes that carry off-center payloads.
• RV slide-outs and campervan roof lifts where 2 corners must travel together.
• CNC machine guards and industrial covers that ride on parallel guides.
• Boat-style hatches and vehicle covers where the lid spans a wide opening.
• Dual-actuator furniture, lab benches, and inspection tables.

How does synchronized actuator control work?

The controller drives both motors from the same command and counts feedback from each actuator. If actuator 1 gets ahead, the controller corrects the motion so actuator 2 can catch up.

That correction matters because 2 actuators never see exactly the same load. Friction changes across the stroke, the screw efficiency varies slightly, and the load rarely sits perfectly centered. Matched actuators reduce the problem. Feedback control solves it during motion.

1. The controller sends extend or retract power to both actuators.
2. Each actuator sends position feedback pulses back to the controller.
3. The controller compares pulse counts.
4. The controller corrects the faster side or allows the slower side to catch up.
5. The controller repeats that comparison through the stroke.

What hardware do you need before wiring?

Start with matched actuators: same stroke, same force rating, same speed, and the same feedback type. Do not mix a 12-inch actuator with a 10-inch actuator and expect software to fix the geometry.

For FIRGELLI systems, the FCB-2 remote actuator controller can synchronize 2, 3, or 4 actuators. You can also use FCB-2 with non-feedback actuators where the control setup calls for it.

You also need a power supply sized for the total current, solid mounting brackets, clean feedback wiring, and enough mechanical guidance to stop side load. Use the linear actuator wiring diagram generator before wiring actuator count, power, switches, feedback, and accessories.

What does Hall or optical feedback actually measure?

Hall and optical feedback do not measure direct rod travel. The feedback device measures rotating gearbox or encoder-disc movement, then the controller converts that pulse count into actuator travel after calibration.

Hall sensors read alternating magnetic poles on a rotating disk. Optical sensors read light pulses through slots in a rotating disk. From a controller point of view, you usually handle both as pulse signals, so compatibility depends on voltage, wiring, pulse type, pulse count, direction handling, and calibration.

If you want the signal-level detail, read Feedback from a Hall Effect Sensor With Video and Hall Effect vs Optical Encoder Actuators: Signals and Setup. For actuator choices, start with feedback linear actuators.

How do you wire 2 actuators for synchronized motion?

Do not simply tie feedback wires together. Each actuator needs its own motor output and its own feedback input at the controller. The controller has to know which pulse train came from which actuator.

Route motor leads away from feedback leads when you can. Use secure connectors, strain relief, and a shared ground scheme that matches the controller instructions. Poor wiring creates false pulses, lost counts, and intermittent faults that look like actuator problems.

For controller details, see the FIRGELLI FCB-2 linear actuator controller guide. For setup videos and control box troubleshooting, use the FCB setup and video guides. The FCB-1 non-remote control box guide covers the non-remote control box version.

How do you calibrate 2 synchronized actuators?

Calibrate before you attach the full load. Extend and retract both actuators through their usable stroke so the controller learns the pulse range. Then attach the mechanism and test again under light load.

Watch the corners during the 1st loaded run. If the panel lifts cleanly but binds near the end, your brackets or guides may force the rods sideways. Calibration cannot fix bad geometry.

Simple Example

A 10-inch lift uses 800 pulses per inch. Actuator A reads 6,000 pulses. Actuator B reads 5,920 pulses.

Δx = |6,000 − 5,920| ÷ 800 = 0.10 inches (2.5 mm).

The lift can still look level, but a tight guide may already feel that error.

How do you calculate synchronization error for a campervan roof?

Let’s calculate the error for a 72-inch wide campervan roof using 2 actuators with 12-inch stroke. The controller reads 7,920 pulses from the left actuator and 8,160 pulses from the right actuator. The actuator feedback gives 800 pulses per inch.

Travel mismatch:

Δx = |7,920 − 8,160| ÷ 800 = 0.30 inches (7.6 mm)

Now check the roof skew angle:

θ ≈ arctan(Δx ÷ W)

Substitute the roof numbers:

θ ≈ arctan(0.30 ÷ 72) ≈ 0.24°

That angle sounds small. On a roof with 0.125 inches of guide clearance, 0.30 inches of corner mismatch already fights the mechanism. Rule of thumb: keep travel mismatch below your guide clearance, then add a margin. For 60-80 inch wide panels, we usually aim for less than 0.125-0.250 inches of corner error before the structure starts to complain.

Which synchronization method should you choose?

If you want to build your own control logic, read How to Sync Two Linear Actuators using an Arduino. If your project may grow past 2 actuators, read How to Synchronize up to 4 Electric Linear Actuators.

What usually goes wrong during troubleshooting?

Related FIRGELLI Products

Use the table below as a short list for synchronized actuator projects. Match the actuator to the load first, then match the controller to the feedback signal.

For mounting, use brackets that match the actuator body and end style. The MB1-P Mounting Bracket for P-series Actuator fits the base end of the Utility Linear Actuator, and the MB17 Mounting Bracket For Super Duty Actuators fits clevis and end mounting on Super Duty Actuators.

If you still need to choose the actuator family, start with linear actuators, actuator controls, the linear actuator selector, or the linear actuator calculator.

What checklist should you run before buying parts?

FAQ

About the Author

Robbie Dickson is the Chief Engineer and Founder of FIRGELLI Automations. With a background in aeronautical and mechanical engineering through Rolls-Royce, BMW, and Ford, he has spent over 2 decades designing precision motion control systems, from linear actuators for robotics to active aerodynamic braking systems for supercars. Read the Full Bio.