Buying guide · For industrial, research and OEM buyers
How to Choose a Motion Platform
Most guides on this subject explain degrees of freedom and stop there. That is the easy part. The decisions that decide whether a motion platform project succeeds are procurement decisions: what order to make them in, how to tell a supplier who engineers from one who assembles, what belongs in the RFQ, and what you agree before signing rather than after delivery.
The short answer: define the physical job first, settle the architecture second, qualify suppliers third, send everyone the same RFQ fourth, compare quotations on scope before price, and write the acceptance criteria into the purchase order. Starting by comparing products — where most projects begin — means choosing before the question has been defined.
Buying guide · Written by the CSCmotion Motion Control Engineering Team · Updated October 5, 2026 · Reading time ~18 min
Fig. 1 · Six decisions, two of them one-way. Most projects that go wrong took the right decisions in the wrong order.
2 of 6
Decisions you cannot reverse
Architecture at fabrication; acceptance at the order.
7
Questions
That separate a builder from an assembler.
12
Scope lines
To normalise before comparing any two quotations.
32
Point checklist
Five project phases, free, no email form.
Order of operations
The Buying Sequence, and Which Steps Cannot Be Undone
Motion platform projects go wrong far more often from sequence than from any single choice. Each step produces the input the next one needs, and two of them are locked for good — one when steel is cut, one when the order is signed.
The 6-Step Buying Sequence Read the last column before skipping a step.
| Step | What you decide | Reversible? | What skipping it costs you |
|---|---|---|---|
| 01 · Define the physical job | What the platform must reproduce, test or move; gross moving load, CoG height, one combined trajectory, duty cycle | Yes — and free to refine now | Every quotation is sized against a different guess |
| 02 · Settle the architecture | Axis count and drive technology, from the motion requirement rather than the budget | No — locked at fabrication | A 3DOF platform cannot become 6DOF; there is no upgrade path |
| 03 · Qualify the suppliers | Who can engineer the platform, not just assemble one | Yes, but costly after an order | You compare datasheets from companies with different capabilities |
| 04 · Issue a comparable RFQ | Identical, complete information to every supplier, including scope boundary and acceptance expectation | Yes — reissuing costs schedule | Quotations arrive that cannot be compared, and you find out late |
| 05 · Normalise and compare | Every quotation adjusted to the same scope before price is read | Until the order is placed | You select the supplier who excluded the most |
| 06 · Agree acceptance, then order | Test load, trajectory, reference point, instrument, tolerance and record format, in writing | Effectively no | Acceptance gets negotiated after delivery, from the weakest position |
What “cannot be undone” looks like: joint spacing, frame geometry and actuator mounting positions are cut into steel. At that point steps 01 and 02 stop being decisions and become the machine — which is why they are taken from the motion requirement, and why the 3DOF vs 6DOF and electric vs hydraulic guides come before any quotation.
Still at step 01? Send what you know about the load and the motion, and get back the list of inputs that are still missing. Get your missing-inputs list →
The most useful hour in the whole process
Seven Questions That Separate Builders From Assemblers
Many companies selling motion platforms buy actuators, buy a controller and bolt them to a frame. That is a legitimate business, and for some projects it is enough. It is also a different capability from designing the mechanism, and you should know which one you are buying from. None of these questions can be answered from a catalogue.
The 7-Question Builder Test Ask every supplier on your shortlist. Our own answers are in the last column, so you can hold us to them.
| Ask this | A builder answers with | An assembler answers with | How CSCmotion answers |
|---|---|---|---|
| 01 · "Who set the attachment geometry, and against what requirement?" | Joint circle radii, angular phase and the workspace trade-offs made | "A standard Stewart configuration" | Our engineers set the joint layout against your trajectory, and every 6DOF platform uses Cardan joints for a determinate load path |
| 02 · "With my payload and trajectory, what peak actuator force results, and at which pose?" | A dynamic solution — or the exact inputs needed first | A figure from static payload alone | Solved from your GML, CoG and trajectory before we quote |
| 03 · "How do you verify structural and modal behaviour?" | Named analyses, run on the real peak loads | "The frame is very strong" | Stiffness, buckling, modal and fatigue checks on the peak limb forces from the dynamic solution |
| 04 · "Who wrote the motion control software, and can you change it?" | "We did, and yes" | The name of another company | We write the kinematics and firmware and build the controller card; changes are a development task, not a support ticket |
| 05 · "Is your accuracy figure measured or derived? With what instrument, at what load?" | A load, a pose set, a reference point and an instrument | Encoder resolution multiplied by a gear ratio | Every figure we give states whether it is a design value or a measured result, and under which conditions |
| 06 · "How do you correct for the difference between the drawing and the machine you built?" | As-built geometry identified and compensated in the controller | "Assembly is to tolerance" | As-built geometry is identified and loaded into the controller before the loaded test |
| 07 · "Can I see your factory acceptance test items before I order?" | A written list, before the order | An offer to write one later | We propose the FAT items for your load case before you order; your team or SGS / BV are welcome to witness |
Here is the honest version: an assembler or integrator can be the right supplier — for a catalogue-sized load case on a tight schedule, or when you need a turnkey simulator rather than a motion system. Ask the questions to know what you are buying, not to rule people out.
Want to rehearse the questions first? Try all seven on us before you use them on your shortlist. We answer each in writing. Try the seven questions on us →
Make the responses comparable
What Belongs in a Motion Platform RFQ
An RFQ is not only for collecting prices. It is for collecting prices that can be compared, which means every supplier gets the same information and is told exactly what the quotation must cover. Where a term is used inconsistently across the industry, our glossary gives the definition we work to.
The 10-Line RFQ Ledger The last column is what goes wrong when the line is missing.
| Include | What it means | If you leave it out |
|---|---|---|
| Gross moving load | Everything that moves: article, fixture, cabin, occupants, cabling, instrumentation | Suppliers size against the payload alone, and the platform is under-rated |
| CoG height and inertia | Height above the platform surface; Ixx, Iyy, Izz about the payload CoG | Rotational demand is unknown, so every quotation carries hidden assumptions |
| One combined trajectory | A realistic motion profile, not a list of per-axis maxima | Suppliers quote against maxima that never occur together |
| Duty cycle | Hours per day, continuous or intermittent, peak versus sustained | Thermal rating cannot be set; actuators may be under-specified |
| Scope boundary | Platform only, or platform plus integration, installation and training | The single largest source of non-comparable quotations |
| Host interface | Protocol, update rate, coordinate convention, who owns integration | Interface work appears as a change order after the order |
| Acceptance expectation | How the platform will be judged to meet the specification | Acceptance is negotiated after delivery, from a weak position |
| Site constraints | Ceiling height, floor loading, power supply, HVAC capacity, access route | A platform that cannot be installed, or needs unbudgeted site work |
| Standards and compliance | Any test standard, safety category or certification you need | Requalification late in the project, or a platform that cannot be signed off |
| Schedule and milestones | Required delivery date and any fixed intermediate dates | Schedule risk is discovered rather than managed |
Why the first two lines matter most: if gross moving load and CoG height are estimated rather than measured, the gap shows up at the loaded acceptance test — when the machine is already built. Weighing the moving assembly costs an afternoon. See Payload, Stroke & Acceleration for why CoG height multiplies the load.
Writing the technical half of the RFQ now? The Specification Builder formats it into one block and marks every unknown, instead of leaving it blank. Generate your RFQ specification block →
Before you look at the numbers
Why Two Motion Platform Quotations Are Rarely Comparable
Quotations for the same platform often differ by a large factor, and the difference is usually scope rather than value. Normalise every quotation to the same twelve lines first, then compare price. The last column is how our own quotation answers each line, so you can normalise us too.
The 12-Line Scope Normaliser Ask every supplier each question in the middle column.
| Scope line | Ask every supplier | CSCmotion quotation |
|---|---|---|
| Motion controller | Included, or priced separately? Whose hardware? | Included — our own controller card |
| Control software licence | Perpetual or subscription? How many seats? What happens at renewal? | Included, with no separate subscription |
| API documentation | Included and documented, or an extra licence? | Included |
| Interface document | Issued before integration starts, or at delivery? | Included, issued before integration starts |
| Factory acceptance test | Included, witnessed or remote? Under what load and trajectory? | Test items proposed before order; witnessing welcome; scope confirmed at quotation |
| Packing and freight | Which Incoterm? Who handles customs and inland delivery? | Confirmed at quotation |
| Installation | Performed, supervised, or documentation only? | Confirmed at quotation |
| Commissioning and tuning | On site, or remote support only? | Confirmed at quotation |
| Training | Operator, maintenance or both? How many people, where? | Confirmed at quotation |
| Warranty | Duration, coverage, response time, on-site or return? | 12 months |
| Spares | Recommended holding, lead time for critical parts, availability period | Confirmed at quotation |
| Site works | Foundation, anchoring, power and HVAC — whose scope? | Confirmed at quotation |
Lowest quote ≠ lowest cost.
The pattern to watch for: a quotation well below the others is worth investigating, not celebrating. Usually it covers the mechanism alone while the others cover a delivered, working system, and the gap comes back as change orders during integration — when you no longer have competitive leverage. Ask the low bidder which of the twelve lines are excluded.
Holding quotations that look nothing alike? Send them — ours included — and we mark which of the twelve lines each one leaves out. Have your quotations normalised →
Where the money goes
What Actually Drives the Price of a Motion Platform
There is no meaningful list price for an engineered motion platform, and a supplier who quotes one before knowing your load and trajectory is quoting a different machine from the one you need. The cost drivers, though, are entirely predictable — and knowing them shows where savings hide.
The 6-Driver Cost Map In rough order of influence.
| Driver | Why it costs | Where the saving usually is |
|---|---|---|
| 01 · Payload × acceleration | Together they set peak actuator force, which sizes cylinders, motors, drives, structure and foundation | An acceleration figure copied from an earlier project, never re-derived from this one |
| 02 · Stroke and envelope | Longer travel grows the whole machine: cylinders, neutral height, structure, footprint, ceiling | Per-axis maxima the real trajectory never reaches |
| 03 · Centre-of-gravity height | It acts as a lever on the actuators; a tall payload needs more capability than its mass suggests | Lowering the fixture or cabin floor — often the cheapest saving available |
| 04 · Duty cycle | Electric actuators are thermally limited; a full shift can need a larger rating at the same peak | Stating duty honestly, rather than assuming the worst |
| 05 · Precision requirement | Tighter repeatability means better components, more calibration and longer acceptance | Specifying what the application needs, not the best number available |
| 06 · Integration and scope | Custom interfaces, protocols, certification support and on-site commissioning add engineering hours | A clear scope boundary in the RFQ |
Where savings usually exist: in requirements nobody examined — a payload with a large unexplained margin, an acceleration from another project, travel at maxima the motion never uses. Re-deriving the requirement from what the platform will really do often shows a smaller machine is enough. That review costs nothing and belongs before any quotation.
Wondering which of your requirements is driving the cost? Send the specification, and an engineer tells you which line to question first. Find your biggest cost driver →
Agree it before the order
Motion Platform Acceptance Criteria and Project Risk
Acceptance is the only mechanism you have for confirming that what arrives matches what was specified. It has to be written before the purchase order, because after delivery the negotiating position is entirely different. “The platform moves as expected” is not a criterion — it cannot be failed, so it cannot be passed either.
The 6-Element Acceptance Statement Every acceptance line in your RFQ needs all six.
| Element | What to write | Why it has to be named |
|---|---|---|
| Test load | The moving assembly, or a stated equivalent mass at a stated CoG | An empty-platform result proves only that the mechanism moves |
| Trajectory | The combined motion profile the platform must reproduce | Single-axis tests hide the combined demand that loads the limbs |
| Reference point | The point on the payload the motion is measured at | Table centre is not the payload CoG; the numbers differ |
| Instrument | What measures the motion, and how it is set up | Two parties can measure the same platform and both be right |
| Tolerance | The threshold for each measured quantity | Without it, every result is open to interpretation |
| Record format | What the signed FAT record contains | It becomes the reference for warranty and future service |
The 4-Risk Register All four are avoidable at specification stage, and expensive afterwards.
| Risk | When it shows up | Mitigation |
|---|---|---|
| 01 · Under-specified moving load | At commissioning, when the fixture and cabin weigh more than the RFQ said | Weigh the assembly, include everything that moves, agree a margin now |
| 02 · Interface mismatch | At integration: platform and host disagree on convention, units, update rate or states | Get the interface document before integration starts and have your host developer review it during build |
| 03 · Acceptance never agreed | At delivery, with no written definition of success | Agree the FAT items during qualification and attach them to the purchase order |
| 04 · Support dependency | At the first fault, when the supplier must escalate to whoever made the actuator or controller | Establish during qualification who makes the critical components and who owns the software |
On risk 04, for transparency: we make our own servo electric cylinders, controller card and control software, so the escalation chain ends with us. We raise it because it is a real difference between suppliers that buyers rarely check — not because every project needs a vertically integrated supplier. If your shortlist includes integrators, ask who they escalate to and what the response commitment is.
Ready to write acceptance into the order? Send your load and trajectory, and we propose the FAT items before you sign. Request proposed FAT items before ordering →
Take it with you
Motion Platform Procurement Checklist
Thirty-two items across the five phases above. Tick them off as you go, then download your progress or print it for the project file. It runs entirely in your browser — nothing is stored or sent, and there is no email form in front of it.
Phase 1 · Define the requirement
Complete before contacting any supplier.
Phase 2 · Settle the architecture
Locked once fabrication begins.
Phase 3 · Qualify suppliers
One conversation per supplier is usually enough.
Phase 4 · RFQ and comparison
Identical information to every supplier.
Phase 5 · Acceptance and budget
Agreed before the purchase order is issued.
Stuck on a Phase 1 line? Send what you have, and an engineer helps you fill the gaps before you go to market. Get help completing Phase 1 →
Frequently asked
How to Choose a Motion Platform — FAQ
The procurement questions we hear most. Engineering questions are answered in the Technology guides; commercial ones in the FAQ.
What does a motion platform cost?
There is no meaningful list price for an engineered motion platform, because cost follows gross moving load, acceleration, stroke, CoG height, duty cycle and precision rather than a model number. Payload multiplied by acceleration dominates, because it sets actuator force and therefore the size of every component. Price is confirmed at quotation, against your full specification.
How do I tell a real engineering supplier from an assembler?
Ask questions a catalogue cannot answer: the peak actuator force at your payload and the pose where it occurs, how the as-built geometry is compensated, who wrote the control software, and what the FAT will measure. An engineering company answers or tells you exactly which inputs it needs first. See the seven questions.
Why are two quotations for the same platform not comparable?
Because the scope boundary differs. One may include the controller, software, interface documentation, FAT, installation and training; another may quote the mechanism alone. Normalise every quotation to the same twelve scope lines before reading the price.
Which costs are usually missing from a motion platform budget?
Host integration labour, usually the largest line after the platform itself. Then foundation and anchoring, HVAC for the heat electric drives reject, safety guarding and interlocks, access and rigging, spares, training, and your own engineers' time to witness acceptance.
How long does a motion platform project take?
An engineered platform passes through engineering review and design, manufacture, assembly, control integration and factory acceptance, then shipping, installation and commissioning. Adapting an existing configuration is much faster than new mechanism geometry. Lead time is confirmed at quotation; ask every supplier which phase carries the most schedule risk.
Should I buy a standard platform or a custom one?
If a standard product meets your gross moving load, trajectory and duty with margin, buy it — it will normally be faster and cheaper, and we will say so ourselves. The trap is a standard platform that nearly fits: the shortfall appears at commissioning, when nothing can be changed. Check it against your combined trajectory, not per-axis maxima.
Does your quotation include the controller and software?
Yes. Our quotation includes our own controller card and control software with no separate subscription, plus API documentation and an interface document issued before integration starts. Installation, commissioning, training, freight terms and spares are confirmed at quotation; the warranty is 12 months.
What are the main risks in a motion platform purchase?
An under-specified moving load found at commissioning, an interface mismatch with the host system, acceptance criteria never agreed, and support that depends on a component maker rather than the platform builder. All four are avoidable at specification stage and expensive afterwards.
The technical decisions
Where the Engineering Questions Are Answered
Deliberately not repeated here. Each guide covers one decision from Phase 1 or 2 in full.
Phase 1
Payload, Stroke & Acceleration
Gross moving load, why CoG height multiplies the moment, and the Specification Builder.
Phase 2
3DOF vs 6DOF
Whether the three axes you would drop carry information your task needs.
Phase 2
Electric vs Hydraulic
Where each drive wins, and what ownership costs after purchase.
Phase 3
How a 6DOF Motion Platform Works
The principle behind questions 01, 02, 05 and 06 — and how to read any spec sheet.
Phase 3
Case Studies
Delivered projects, described by industry and load class.
Reference
Glossary
The definitions we work to, for the terms suppliers use inconsistently.
Use us as a second opinion
Test This Guide on Us First
Early in a procurement and want to try the Phase 3 questions before using them on your shortlist? Ask us. We answer them properly — and if the honest answer is that another kind of supplier suits your project better, we will say so.
An engineer, not a sales inbox, replies within 24 hours — weekends included. cscmotionglobal@gmail.com · +86 152 5530 5272