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Motion Platform Technology, Engineered and Measured In-House
We derive the kinematics, run the structural and modal analysis, write the control algorithms and measure the finished machine on a laser system. This section explains how our motion platforms actually work — and how we know that they do.
Motion platform technology covers the parallel mechanism, forward and inverse kinematics, structural dynamics, control algorithms, safety architecture and verification methods used to produce controlled multi-axis motion.
6-TPS mechanism
ANSYS + ADAMS
Hexagon laser metrology
127 patents filed
Six Analyses Stand Between a Requirement and a Platform
Many motion-platform suppliers begin at assembly: buy actuators, buy a controller, bolt them to a frame. Our design chain starts one level earlier, at the mechanism itself. Every platform we ship passes through the same six analyses, in the same order, feeding the same toolchain.
Short answer
A motion platform is only as trustworthy as the analysis behind it. Mechanism → kinematics → dynamics → modal → structural → identification. Each stage produces an input that the next stage cannot proceed without, and the last one is what turns a design intent into a measurable specification.
01 · Mechanism Analysis
The platform is a 6-TPS parallel mechanism: moving and fixed frames joined by six servo electric cylinders through Cardan joints, with the piston-and-barrel pair contributing prismatic and rotational freedom. Mobility is derived from the constraint equations rather than assumed from a reference layout.
02 · Forward & Inverse Kinematics
Inverse kinematics maps a commanded pose to six cylinder lengths in closed form. The forward problem has no general closed-form solution, so we solve it with a neural-network estimate refined by numerical iteration and validated against simulation. Workspace envelope is mapped by Monte Carlo sampling.
03 · Dynamic Analysis
Multibody dynamics returns the theoretical peak thrust each cylinder must deliver across the commanded motion envelope, including the payload, fixture and cabin mass. That figure sizes the servo electric cylinder — and then becomes the load case handed to structural analysis.
04 · Modal Analysis
Natural frequencies at representative poses are computed twice, on two independent theoretical foundations: finite element and variational principles in ANSYS, multibody dynamics and the Euler-Lagrange formulation in ADAMS. Agreement between the two is the acceptance condition, not a bonus.
05 · Structural FEA
Element stiffness matrices and load vectors assemble into the global equilibrium equation [K]{δ} = [P]. Static strength is checked against a design criterion carrying an explicit safety factor, and Cardan joints are optimised for alternating load — the condition that governs fatigue life in a motion base.
06 · Parameter Identification
Manufacturing tolerance and assembly deviation push real kinematic parameters away from their design values. Calibration identifies the geometry that was actually built and compensates it inside the controller. This is where an accuracy specification stops being a design target and becomes a property of the machine.
Why the double check matters. ANSYS and ADAMS arrive at natural frequency from different physics. When they agree, the structural model is credible. When they disagree, the model is wrong — and we find that out before steel is cut, rather than during factory acceptance with a customer in the room.
Technical guides
Choose the Engineering Question You Need to Resolve
Ten guides, grouped by the decision each one supports. They go into depth on a single topic so that this page does not have to — start with the group that matches your project stage.
Working principles
For readers who need to understand the mechanism before evaluating any product.
How a 6DOF Motion Platform Works
Six actuator lengths, one rigid-body pose: how surge, sway, heave, roll, pitch and yaw are produced simultaneously by a parallel mechanism.
Read the working principle →
Stewart Platform Design
Joint circle radii, limb angles and platform ratios, and how each geometric choice trades workspace against stiffness and force capability.
Read the design guide →
Hexapod Kinematics
Inverse kinematics in closed form, the forward problem and why it needs iteration, plus singularities and the Jacobian condition.
Read the kinematics guide →
Architecture selection & sizing
For readers comparing concepts before a specification is written.
3DOF vs 6DOF Motion Platform
What three axes can and cannot reproduce, the cost and complexity step between them, and how to decide from the motion task rather than the budget.
Compare the architectures →
Electric vs Hydraulic Motion Platform
Bandwidth, payload ceiling, energy use, maintenance burden, noise and site requirements — where each actuation type still wins.
Compare the actuation →
Payload, Stroke & Acceleration
Why headline numbers are not comparable in isolation, and which inputs — mass, centre of gravity, inertia, combined trajectory, duty — actually size a platform.
Read the sizing guide →
Control & motion software
For readers defining the algorithm and software boundary with a host system.
Motion Cueing Algorithm
Washout filtering, tilt coordination and angular-rate limiting below the human perception threshold — how a finite envelope reproduces sustained acceleration.
Read the cueing guide →
Motion Control Software
What the controller owns: trajectory generation, real-time kinematics, servo loop, state machine, fault handling, logging and the host API surface.
Read the software guide →
Motion Platform Safety System
Hazard boundary, stop categories, guarding, and why software limits in the application layer are not a substitute for a safety architecture.
Read the safety guide →
Integration
For readers moving from an agreed specification into a real installation.
Motion Platform Integration Guide
Commands, units, coordinate conventions, timing and latency, state transitions, limits, fault behaviour, site utilities and who owns each acceptance test. The document that prevents a working platform from failing at the interface.
Read the integration guide →
Controller & API Integration
The delivered controller, its API and the responsibility split between platform and host, documented as a project work package.
See the work package →
How a Repeatability Figure Becomes an Engineering Fact
An accuracy specification means nothing without the chain that produced it. Ours has three links, and all three happen in Nanjing before the platform is crated.
Kinematic Calibration
The as-built geometry is identified and compared against the design model. Deviations from manufacturing tolerance and assembly are compensated inside the controller, so the solver commands the machine that exists rather than the machine that was drawn.
Laser Measurement
Positioning accuracy and repeatability are measured on a Hexagon three-axis laser measuring system at defined poses across the workspace. The result is an instrument reading traceable to a stated setup, not a value inferred from actuator resolution.
Factory Acceptance Re-Test
The measurement is repeated under the test load, trajectory and reference point agreed in the project. Instruments, tolerances and results are recorded in the FAT report that ships with the platform and can be re-run on site.
How to read anyone's accuracy number — including ours
A positioning or repeatability figure is only comparable when four things are stated alongside it. Ask for all four, from every supplier on your shortlist:
- The test load on the platform when the measurement was taken
- The poses or trajectory used, and whether they span the full workspace
- The reference point the value applies to — table centre is not the payload centre of gravity
- The instrument and whether the result was measured or derived from component specifications
The Algorithms Are Ours, Not a Licensed Black Box
Motion cueing, trajectory planning, the real-time kinematic solver and the servo layer are developed in-house and protected by our software copyrights. That matters at integration time: when behaviour needs to change, it is a development task rather than a support ticket to a third party.
| Application & vehicle model | Scene, mission logic, test sequence — normally customer-owned |
|---|---|
| Motion cueing | Low-pass acceleration channel · second-order filter · tilt coordination · rate limiting below perception threshold |
| Trajectory planning | T-curve and S-curve profiles · DDA interpolation · quintic non-uniform B-spline fitting |
| Real-time kinematic solver | Commanded pose to six cylinder lengths, with workspace and singularity guarding ` |
| Servo & disturbance rejection | ADRC and fractional-order control per axis · frequency-response characterised |
| Safety & limit layer | Independent of application logic · stop behaviour, envelope limits, fault states |
The stack on the right is the boundary that appears in every project interface document. Everything below the dashed line is delivered and maintained by us. The application above it — the vehicle model, scene, mission logic or test sequence — normally stays with the customer, and the contract defines exactly where the handover sits.
Inside our layers, the components are specific rather than generic. Motion cueing uses a low-pass acceleration channel with second-order filtering, a tilt-coordination module and angular-rate limiting held below the human perception threshold. Trajectory planning offers T-curve and S-curve profiles, DDA interpolation and quintic non-uniform B-spline fitting. The servo layer applies active disturbance rejection control and fractional-order methods on each axis.
Scope note: the algorithm set above is our standard offering. Which elements are enabled, tuned or exposed through the API is a project decision — see Motion Control Software and the Motion Control System product page.
We Wrote the Coordinate Standard We Design Against
Parallel-robot coordinate conventions are inconsistent across the industry, which is a recurring source of integration failure — the platform moves correctly and the host still disagrees about which direction is positive pitch.
Rather than accept that ambiguity, we authored our own specification for coordinate-frame definitions and motion sign conventions across 2, 3, 6 and 7 degree-of-freedom parallel robots. It governs our internal design work, our controller and every interface document we issue.
Practical effect: when you receive an interface document from us, the coordinate frame, origin, sign convention and reference point are already defined and consistent with the controller. That removes one of the most common causes of first-power-on surprises.
Take the Technology Into a Product, Application or Project
This section explains how the machines work. The four routes below turn that understanding into something you can specify, budget or verify.
Motion Platforms
Compare 3DOF, 6DOF and Stewart architectures, electric drive, high-payload and compact configurations, and the motion control system that runs them.
Applications
Industrial testing, research, driving and flight simulation, motion compensation and maritime motion — each brings its own load, duty cycle and validation method.
Technology
Stewart geometry, hexapod kinematics, motion cueing, safety architecture, and how payload, stroke and acceleration constrain each other.
Resources
Buying guides on choosing a platform, budgeting a project, comparing manufacturers and deciding whether to build or buy.
Case Studies
Delivered projects with the requirement, the engineering decisions, the interfaces we owned and the measured validation behind them.
Company
A 20,000 m² production base in Nanjing with in-house servo cylinder and controller manufacturing, ISO 9001 / 14001 / 45001 and documented acceptance testing.
Motion Platform Technology Questions
Short answers to the questions engineers ask most often. Detailed derivations, project values and design choices belong in the relevant guide or an engineering review.
What does motion platform technology include?
It covers the parallel mechanism and its joints, forward and inverse kinematics, structural and modal behaviour, actuators and feedback, the motion controller and its algorithms, the host interface, safety functions, and the measurement methods used to verify all of it.
Does CSCMotion deliver complete simulators?
Inverse kinematics is a closed-form geometric calculation — a commanded pose maps directly to six actuator lengths. The forward problem, six lengths to one pose, has no general closed-form solution and admits multiple mathematical roots. We solve it with a neural-network estimate refined by numerical iteration and validated against simulation.
How is motion platform accuracy actually measured?
Kinematic parameters are first identified and compensated to correct manufacturing and assembly deviation. Positioning accuracy and repeatability are then measured on a Hexagon three-axis laser measuring system at defined poses, and re-tested during factory acceptance under the agreed test load and trajectory. Always ask which load, poses, reference point and instrument a published figure refers to.
Is a Stewart platform the same thing as a 6DOF motion platform?
No. Six degrees of freedom describes the controlled motion; Stewart platform describes a mechanism architecture. Our platforms use a 6-TPS parallel configuration — a Stewart-type arrangement in which six servo electric cylinders connect the moving and fixed frames through Cardan joints.
Can these guides replace a project-specific engineering review?
No. The guides explain principles, inputs and trade-offs. Final geometry, component selection, achievable performance, safety responsibilities, interfaces and acceptance criteria must be reviewed against your actual payload, motion profile, installation and application.
Ask Our Engineers a Technical Question
If something on this page or in one of the guides does not resolve your question, send it directly. Technical questions are answered by the engineering team, not by a sales inbox — and asking one does not put you into a quotation process.
Questions we answer well
The more specific the question, the more useful the answer. These are the kinds engineers send us most often:
Can this payload and centre of gravity reach that acceleration?
What natural frequency should we expect at a given pose?
How is your coordinate convention defined against ours?
What does the API expose, and at what update rate?
How would acceptance be measured for this trajectory?