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Heave · Roll · Pitch
3DOF motion platform, electric, sized to your load case.
Three axes do the work when the task lives in three axes. Reference classes run to 1,000 kg gross moving load; above that we design the frame to your moving assembly.
Not sure three axes are enough? The step-up test further down settles it in one question.
Heave, roll and pitch from three servo electric cylinders against a constrained centre.
3DOF
Controlled axes: heave, roll and pitch
to 1,000 kg
Gross moving load in reference classes; above that, project frame
≥ 2 Hz
Bandwidth at −3 dB where the build is specified for test work
> 3 ×
Rated load design factor on mechanical parts, FEA verified
12 months
Warranty, with the acceptance record shipped alongside
Where three axes are the right answer
A 3DOF motion platform is not a cheaper six-axis platform
It is a different machine with a different constraint. Heave, roll and pitch are produced against a constrained centre, so the load path is shorter and stiffer than a six-leg parallel mechanism carrying the same mass.
That geometry is why a right-sized 3DOF motion platform holds its motion with less installed power, a smaller footprint and fewer parts under maintenance. It is also why it cannot be talked into surge, sway or yaw later — those axes are absent from the mechanism, not merely unconfigured.
So the question worth settling before anything else is whether the three missing axes carry information your task depends on. If they do, this is the wrong page and the 6DOF platform is the right one. If they do not, everything below is about sizing rather than architecture.
Three axes, chosen deliberately, beat six axes bought as insurance.
Working from a specification that just says “3DOF”? Send it and we will confirm the axes it really needs →
Three actuators, one constrained centre. Surge, sway and yaw are absent from the mechanism rather than switched off.
Where your load case lands
The 5-Class 3DOF Reference Ladder
Reference designations follow the pattern ACE-3DOF-{rated payload in kg}. The class matters more than the code, because the class is what decides which constraint governs the frame.
| Class | Gross moving load | What governs the design | Typically specified for |
|---|---|---|---|
| Compact | 20 – 100 kg | Fixture stiffness rather than actuator force. A soft adapter plate is usually the real limit on measured performance. | Component-level test rigs, optical and sensor benches |
| Light | 100 – 300 kg | Centre-of-gravity height begins to dominate the moment; two builds at the same mass diverge here. | Single-seat trainers, instrument platforms, small test articles |
| Mid | 300 – 600 kg | Actuator force and frame stiffness get sized together; neither can be raised alone. | Cabin sections, multi-axis test fixtures, laboratory rigs |
| Heavy | 600 – 1,000 kg | Foundation loading and installation access enter the design as hard constraints. | Full cabin trainers, vehicle sub-assemblies, durability rigs |
| Above the ladder | Over 1,000 kg | No reference frame applies. Geometry is designed to your moving assembly and analysed against your load path. | Project-specific three-axis platforms, quoted per case |
Gross moving load means everything above the mounting plane — your equipment, the fixture, the adapter and the cabling — not the mass on the drawing. Linear acceleration across the classes falls between roughly 0.1 g and 1.0 g; where a build lands depends on the class, the centre-of-gravity height and whether axes are commanded singly or together.
Know the mass but not which class? Send mass and CG height — that is enough to place it →
The input most enquiries leave out
Mass alone does not size a three-axis platform
The actuators do not hold your equipment. They control it through a lever equal to the centre-of-gravity height, so the demand on the machine scales with mass, acceleration and that height together.
Two assemblies at the same 600 kg illustrate it. One sits flat on the mounting plane; the other carries that mass 1.8 m above it. At the same commanded acceleration the second places roughly three times the moment on the same three actuators, and no amount of servo tuning changes that — it is geometry, not control.
Roll and pitch are where it shows first, because both are produced by differential actuator motion against the constrained centre. A platform that holds heave comfortably can run out of authority in roll on the same payload if the centre of gravity is high.
Send mass and CG height together. Separately, neither one sizes anything.
Moment scales with mass × acceleration × CG height. The second assembly needs a different frame, different actuators and a different quotation.
Have CAD but not the mass properties? Send the model — we will pull mass, CG and inertia from it →
What arrives with your configuration
Every field on your project datasheet, and the condition attached to it
A number without its condition is not a specification. These are the fields we issue for a 3DOF build and what each one is measured against, so you can compare our datasheet with anyone else’s line by line.
| Field | Stated as | Condition it is measured or rated at |
|---|---|---|
| Gross moving load | kg | Total mass above the mounting plane, including fixture, adapter and cabling |
| Maximum CG height | mm | Above the mounting plane, at the rated load |
| Heave travel | ± mm | Single axis, at the rated load and rated CG height |
| Roll and pitch range | ± ° | Single axis; combined roll and pitch is smaller and is stated separately |
| Peak linear acceleration | g | At the rated load, single axis, with the axis commanded alone |
| Peak angular rate | °/s | At the rated load and rated inertia |
| Bandwidth | Hz at −3 dB | Working range stated alongside; issued where the build is specified for test work |
| Repeatability | mm | Laser tracker on the assembled platform at the acceptance load, not encoder feedback |
| Site supply | kVA, V, phases | Sized for the configuration, stated with the breaker rating |
| Footprint and neutral height | mm | With the mounting pattern and the access clearance required for service |
| Enclosure rating | IP | Standard indoor build; IP55 and other ratings on request |
Combined-axis travel is always smaller than single-axis travel. A datasheet listing heave, roll and pitch at their individual maxima is three best cases rather than one workspace, which is why we check a trajectory before issuing figures rather than after.
Comparing two datasheets that look similar? Check what conditions each one attaches →
How a 3DOF motion platform reaches acceptance
Four stations, then measured under load
The servo cylinders are machined in our own plant, which is why stroke, rod diameter and mounting arrangement are project variables rather than catalogue constraints.
ST 01
Cylinder machining
Cylinder bodies, rods and end fittings cut to the project stroke; screw drive and motor matched to force and duty.
ST 02
Frame and centre joint
Base and moving frame built to the released geometry, with the centre constraint set and its preload recorded.
ST 03
Geometry calibration
As-built dimensions measured and the difference from design values compensated inside the controller.
ST 04
Loaded acceptance
Run with a test load standing in for your payload — envelope, cycle time, thermal behaviour and safety functions.
Thresholds a 3DOF build is accepted against
| Criterion | Threshold |
|---|---|
| Continuous-operation drift | ≤ 0.25 mm per cylinder |
| Loaded static hold | ≤ 0.1 mm and ≤ 0.01° |
| Single-cylinder steady-state error | 0.1 mm |
| Bandwidth at −3 dB | ≥ 2 Hz, 0–15 Hz working range |
| Supply disturbance | ±20 % fluctuation or sudden loss |
| Mechanical design factor | > 3 × rated load |
Not every line applies to every build. Which criteria govern your platform is agreed before manufacturing and written into the acceptance protocol, and the protocol can be sent in blank before you order.
Acceptance runs with a test load standing in for the real payload. The load figure is recorded next to every performance number in the report.
Writing acceptance criteria into a tender? Ask for the 3DOF acceptance protocol in blank →
Motion you can watch, not just read
3DOF motion platform running
Each clip states the payload it was carrying and what the motion was reproducing. A platform filmed empty proves the actuators move; it proves nothing about your load.
500 kg Payload Motion Test——A 3DOF motion platform operating with a 500 kg test load. The demonstration shows roll and pitch motion, including single-axis and combined-axis movement.
Compact 3DOF Platform Demonstration——A compact 3DOF motion platform demonstrating three-axis movement in the workshop. The video provides a clear view of the platform’s motion and enclosed mechanical layout.
Compact Enclosed 3DOF Motion Platform——A compact platform with protective bellows and a flat moving top for integration with a customer-specific seat, fixture or payload structure.
Low-Profile 3DOF Motion Base——This square-format platform packages the motion mechanism inside a compact enclosed base, with a flat top interface for the customer’s assembly.
Large-Frame 3DOF Platform——A larger rectangular moving frame shows how the platform geometry can be adapted to the footprint and mounting points of the intended payload.
Open-Frame 3DOF Platform——An uncovered factory-stage build providing a clear view of the actuator arrangement, fixed base and moving-frame structure.
3DOF Platform with Spherical Cabin——A customer-specific spherical cabin mounted on a three-axis motion base, illustrating payload integration beyond a standard flat fixture.
Multiple 3DOF Platforms in Production——A workshop view of several low-profile units built around the same core platform format, showing how the design can be repeated across multiple systems.
Want to see one running with your payload class? Tell us the mass and we will send the closest recording →
Delivered three-axis work
What a 3DOF motion platform project record contains
Each record is written the same way: the constraint that governed the design, the engineering decision taken because of it, and what was measured at acceptance. Where a customer allows the name to be published it is published; the rest carry the parameters without the logo.
Photo 09 · Cabin trainer platform
cscmotion-3dof-case-cabin-trainer.webp
Constraint · Ceiling height
A cabin trainer under a 4.5 m ceiling
The site ceiling set the neutral height before any actuator could be selected, which capped heave travel and pushed the design toward a longer roll arm to recover the motion cue.
Photo 10 · Durability rig
cscmotion-3dof-case-durability-rig.webp
Constraint · Duty cycle
A durability rig running six hours a day
Continuous duty moved the governing criterion from peak acceleration to drift. The build was accepted against the 12-hour drift threshold rather than a headline acceleration figure.
Photo 11 · Optical test bench
cscmotion-3dof-case-optical-bench.webp
Constraint · Fixture stiffness
A compact bench where the fixture was the limit
At this payload the customer’s adapter plate, not the actuators, set the measured performance. The plate was redesigned as part of the scope before any figure was issued.
Looking for a record close to your own project? Open the delivered project library →
The one question that sends you elsewhere
When three axes stop being enough
Not “would six be nicer” — does the task fail without surge, sway or yaw? Four situations answer it without interpretation.
Step up to six axes
- The standard you test to specifies lateral input
- Recorded field data you must reproduce contains surge or sway
- The motion cue depends on translation the operator can feel
- The pose itself is the measured quantity, not the motion
Stay with three axes
- Attitude and vertical motion carry the whole requirement
- Yaw is needed but only as slow indexing, which a rotary stage covers
- Installed power, footprint or maintenance load are real constraints
- The task is repeated daily and simplicity is worth more than range
A note on upgrading later
A three-axis platform does not become a six-axis platform by adding actuators. The mechanism, the frame and the control geometry differ from the outset.
What is possible is planning a second machine around a shared interface and coordinate convention so your host software carries over. If that matters, say so at the requirement review — it changes what we design now.
Genuinely on the line between the two? Read the full comparison →
Agreed before manufacturing
How your host commands three axes
The controller and its boards are designed and built here, so command level and coordinate convention are things we change rather than things you work around.
Host communication runs over TCP/UDP or serial/Modbus; drive-level communication over EtherCAT or CANopen. We hold membership of the EtherCAT Technology Group and CAN in Automation, and our CANopen implementation is conformance tested. Which of these your build uses is a configuration decision, not a fixed list.
Message content, units, update behaviour, fault response and the coordinate convention are written down at the interface freeze and signed before anything is manufactured. Retrofitting a convention after the frame is welded is the expensive way to discover it was ambiguous.
Already have a command set in use? Send it and we will map it to the platform →
3-axis motion platform control architecture with host, controller, EtherCAT, CANopen and three servo axes
Written into the proposal
What a 3DOF motion platform supply includes, and what your team keeps
Inside the supply
- Three-axis mechanism and the contracted top interface
- Servo electric actuation, drives and feedback
- Platform controller and electrical cabinet
- Platform-side commands, status and safety I/O
- Configuration drawings, manuals and spare parts list
- Loaded acceptance test and the measurement record
- Twelve-month warranty
Normally yours
- Your payload, fixture and adapter design unless quoted
- Test instrumentation and data acquisition
- Host application, courseware or simulation content
- Foundations, site power, permits and site-wide safety
- Complete-system certification and operational approval
What to send for an accurate quote
- Gross moving load and CG height above the mounting plane
- Inertia or CAD mass properties
- Heave travel, roll and pitch range, and the reference point
- One representative motion profile or the test standard
- Ceiling height, footprint and access route
- Site supply and any ingress requirement
- Host system and intended acceptance method
Blanks are fine and more useful than estimates. What comes back first is a completeness review and a gap list, typically within one business day — and if a reference class already covers your requirement, that is what you will hear rather than a case for a project build.
Only have the first two items? Enough for a first pass — send them →
Asked before the drawings come out
3DOF motion platform FAQ
What payload can a 3DOF platform carry?
Reference classes run to 1,000 kg gross moving load — everything above the mounting plane, including your fixture, adapter and cabling. Above 1,000 kg no reference frame applies and the geometry is designed to your moving assembly. The rating is always confirmed against centre-of-gravity height and inertia before a figure is issued, because the same mass at two different CG heights is two different machines.
Why is a 3DOF platform not simply cheaper than a 6DOF one?
Because most of the cost sits in the actuation, the frame and the control, and a three-axis platform carrying the same mass at the same acceleration needs comparable actuator force per axis. What you save is installed power, footprint, parts under maintenance and commissioning time — real savings over the life of the machine rather than a proportional discount on the purchase price. If someone quotes you half price for half the axes, ask what load their figures were measured at.
Can I add the other three axes later?
Not as a retrofit. The mechanism, the frame and the control geometry are different from the outset, so a three-axis platform does not become a six-axis platform by bolting on actuators. What is possible is planning a second machine around a shared interface and coordinate convention so your host software carries over unchanged. If an upgrade path matters, raise it at the requirement review, because it changes what we design now rather than what we do later.
I need yaw as well. Does that rule out a 3DOF platform?
Not necessarily. If the yaw requirement is slow indexing rather than a commanded motion cue, a rotary stage in series above the three-axis platform reaches the range without moving to a six-leg mechanism — and it usually reaches a wider yaw range than a parallel platform of the same size could. If yaw has to be commanded as part of a coordinated trajectory, that is a six-axis requirement.
How do I know the stated performance holds with my equipment on it?
Because acceptance runs with a test load standing in for your payload, and the load figure is recorded next to every performance number in the report. Repeatability is measured by laser tracker on the assembled platform rather than inferred from encoder feedback — encoder agreement proves the control loop closed, not that the payload arrived where it was commanded. You can witness the test at the plant in person or by live video, and third-party witnessing is accepted.
What happens if my requirement falls between two reference classes?
We tell you which side it falls on and why. Usually the answer is the higher class with a shorter stroke, or the lower class with a stiffer fixture — and occasionally it is that a released configuration does not fit at all and a project-specific frame is the honest answer. If a reference class does cover your requirement, that route wins on both price and lead time and it is what we will recommend.
Do you supply the complete trainer or test rig?
No. We supply the three-axis platform, its control equipment and the platform-side interface. Your payload, fixture, instrumentation, host application and any courseware stay with you or your integrator, and complete-system certification sits with whoever owns the finished machine. The scope list on this page goes into the proposal in the same words, so nothing about the boundary is discovered at commissioning.
Commercial questions — lead time, payment, spares, support: Answered in the full FAQ →
From the three-axis line
Engineering notes and project updates
The reference reading buyers ask for most often when specifying a three-axis platform.
Selection
3DOF or 6DOF: which axes your task actually needs
The onset window, what a lateral cue carries, and why dropping three axes is either free or fatal depending on the task.
Sizing
Payload, stroke and acceleration are not independent
Why fixing any two determines the third, and how CG height turns the same mass into a different machine.
Drive technology
Electric or hydraulic for a three-axis platform
Where hydraulics still win, where electric drives win on total cost, and which questions decide it for a given duty.
Delivered work
Three-axis project records
Constraint, decision and measured result for delivered platforms, including builds where a reference class was the right answer.
Send the mass and the height. We will place it in a class.
Gross moving load and centre-of-gravity height are enough for a first pass. Everything else can follow, and if a reference class already covers your requirement you will hear that rather than a case for a project build.