FULL GUIDE
A practical framework for comparing integrated joint suppliers
Integrated robot joint selection is partly an engineering decision and partly a supplier decision. The engineering team must compare product-level fit, but they must also confirm whether the supplier can support the program with usable documentation, reliable communication, prototype availability, and future production readiness.
A strong supplier comparison framework helps teams avoid choosing a joint that looks attractive in a summary table but creates risk during integration, testing, or sourcing.
A blank field is not proof that the specification is zero or equivalent to another supplier. If a required technical or commercial field is not available for the exact model, treat it as missing information and capture it for supplier follow-up.
1. Start With One Shared Requirement Set
Supplier comparison is only useful when all candidates are evaluated against the same joint requirement.
Define the shared requirement set before comparing suppliers.
Capture:
- - Continuous output torque
- - Peak output torque
- - Output speed
- - Acceleration profile
- - Motion range
- - Payload
- - Gravity load
- - Radial load
- - Axial load
- - Moment load
- - Duty cycle
- - Backlash target
- - Stiffness requirement
- - Positioning requirement
- - Thermal environment
- - Voltage architecture
- - Control mode
- - Communication interface
- - Available envelope
- - Hollow-bore requirement
- - Prototype quantity
- - Target production stage
Do not compare suppliers using different assumptions for different candidates.
A fair comparison requires one common requirement set.
For the product-level selection process behind this framework, read How to Select an Integrated Robot Joint.
2. Compare What Each Supplier Actually Integrates
The phrase "integrated robot joint" can describe very different products.
Some suppliers integrate nearly the full actuation stack, while others integrate only part of it.
| Function | Questions to compare |
|---|---|
| Motor | Is the motor integrated? Is the motor architecture described? |
| Reducer | What reducer architecture and ratio are used? |
| Encoder | Is sensing motor-side, output-side, or dual-encoder? |
| Driver | Is the driver integrated or external? |
| Output bearing | Can the joint directly support radial, axial, and moment loads? |
| Brake | Is a brake included, optional, or absent? |
| Housing | Is the product a finished structural module? |
| Thermal sensing | Are motor, case, or driver temperature signals available? |
| Communication | What command and feedback interfaces are documented? |
Two suppliers should not be treated as equivalent if one offers a complete joint module and the other offers only a partially integrated assembly.
3. Compare Torque, Speed, and Duty-Cycle Fit
Start with the core engineering fit.
Compare:
- - Continuous torque
- - Peak torque
- - Peak duration
- - Rated speed
- - Maximum speed
- - Continuous operating range
- - Acceleration capability if documented
- - Duty-cycle basis
- - Thermal assumptions
Do not compare peak torque alone.
A supplier with a strong peak number may still be a weaker candidate if continuous performance, peak duration, or thermal basis is unclear.
| Field | What to compare | What to confirm |
|---|---|---|
| Continuous torque | Repeated operating capability | Thermal basis and duty cycle |
| Peak torque | Transient capability | Allowed duration and repetition |
| Rated speed | Normal operating speed | Voltage and test condition |
| Maximum speed | Upper operating limit | Whether it is continuous or momentary |
| Duty cycle | Motion and load profile | Whether supplier data matches application use |
4. Compare Backlash, Stiffness, and Precision-Relevant Behavior
Integrated joint comparison should include mechanical precision, not only encoder resolution.
Compare:
- - Reducer backlash
- - System backlash
- - Torsional stiffness
- - Repeatability
- - Compliance under load
- - Direction reversal behavior
One supplier may publish encoder resolution but not joint backlash.
Another may publish backlash but not stiffness.
Treat these as different documentation profiles, not directly comparable proof of equal joint precision.
5. Compare Encoder and Feedback Architecture
The feedback architecture can materially change how the joint behaves in the robot.
Compare:
- - Motor-side encoder
- - Output-side encoder
- - Dual encoder
- - Absolute or incremental sensing
- - Encoder technology
- - Published resolution
- - Published accuracy
- - Available feedback signals
- - Diagnostic visibility
| Question | Why it matters |
|---|---|
| Where is position measured? | Affects visibility into backlash and compliance |
| Is output-side sensing available? | Can improve actual joint-position visibility |
| Is the encoder absolute? | Affects startup and homing behavior |
| What feedback is exposed? | Affects controls integration and diagnostics |
| What accuracy is documented? | Resolution and accuracy are not the same |
Do not equate high encoder resolution with high finished-joint accuracy.
6. Compare Driver and Control Integration
Some integrated joints include the driver and internal control electronics.
Others require an external drive or expose only limited control modes.
Compare:
- - Driver included or external
- - Bus voltage
- - Continuous current limits
- - Peak current limits
- - Position control support
- - Velocity control support
- - Torque / current control support
- - Feedback modes
- - Configuration workflow
- - Firmware or tuning tools
- - Fault handling if documented
A supplier may have strong mechanical performance but still create integration risk if the available control modes do not match the robot architecture.
7. Compare Communication Interfaces
Communication compatibility should be checked early.
Only use interface names that are explicitly documented for the exact product.
Compare:
- - Command interface
- - Feedback interface
- - Connector type
- - Cable routing
- - Electrical documentation
- - Configuration tooling
- - Fault and status reporting
Do not infer protocol support from another model in the same supplier family.
A missing communication detail should remain a supplier question until confirmed.
8. Compare Output Bearing Support
Some integrated joints can directly support robot-link loads.
Others still require additional structural bearings.
Compare:
- - Radial load capacity
- - Axial load capacity
- - Moment load capacity
- - Combined load statements
- - Bearing architecture if described
- - Life basis if published
This difference can materially affect joint housing design, stiffness, assembly complexity, and package size.
If one supplier publishes bearing-load data and another does not, that is a documentation difference that should be recorded explicitly.
9. Compare Thermal Capability and Derating
Thermal limits are often the hidden constraint in compact integrated joints.
Compare:
- - Continuous torque thermal basis
- - Ambient temperature
- - Case temperature
- - Motor temperature sensing
- - Driver temperature sensing
- - Cooling method
- - Thermal derating
- - Over-temperature protection
- - Duty-cycle assumptions
A supplier that publishes a complete thermal basis may be lower risk than a supplier with similar torque numbers but less thermal transparency.
10. Compare Mechanical Envelope and Integration Effort
Integrated joints may reduce packaging complexity, but actual integration effort can still differ substantially.
Compare:
- - Outer diameter
- - Total length
- - Output flange
- - Mounting pattern
- - Hollow bore
- - Connector clearance
- - Cable exit direction
- - Weight
- - Brake extension if applicable
- - Installation constraints
The goal is not only to compare size.
It is to compare the total effort required to integrate the joint into the robot.
11. Compare Documentation Quality
Documentation quality is one of the clearest differences between suppliers.
Compare whether each candidate has:
- - Dimensional drawing
- - CAD files
- - Electrical pinout
- - Communication documentation
- - Torque-speed data
- - Thermal data
- - Bearing-load data
- - Backlash data
- - Stiffness data
- - Encoder documentation
- - Control-mode documentation
- - Environmental information
- - Life or reliability information
| Documentation item | Why it matters |
|---|---|
| CAD / dimensional drawing | Supports packaging and mounting design |
| Electrical documentation | Reduces wiring and interface risk |
| Communication documentation | Reduces software integration risk |
| Torque-speed / thermal data | Supports engineering validation |
| Bearing / stiffness data | Supports structural and control decisions |
| Life / reliability information | Supports build-readiness decisions |
A technically promising product with weak documentation may still be the wrong prototype choice if the schedule is tight.
12. Compare Prototype Support and Commercial Readiness
After engineering fit, compare how each supplier supports the build.
Review:
- - Exact model availability
- - Sample availability
- - Prototype quantity support
- - MOQ
- - Lead time
- - Commercial responsiveness
- - Customization options
- - Replacement availability
- - Future production capacity
- - After-sales or technical support
- - Second-source flexibility where applicable
Do not assume price, inventory, MOQ, or lead time unless the supplier has published or confirmed them.
Use RFQ to capture missing commercial fields.
13. Compare Supplier Risk, Not Only Product Fit
A supplier comparison should include risk beyond product performance.
Consider:
- - Concentration risk
- - Dependence on proprietary architecture
- - Documentation completeness
- - Support responsiveness
- - Unclear firmware dependence
- - Lack of second-source path
- - Uncertain scaling capability
- - Uncertain replacement or repair process
A slightly less optimized candidate may still be the better build decision if it materially reduces program risk.
14. Use a Weighted Comparison Framework
Not every project values the same factors equally.
A humanoid joint, industrial manipulator joint, and field robot joint may weigh criteria differently.
| Category | Example questions |
|---|---|
| Performance fit | Does torque-speed capability match the application? |
| Mechanical architecture | Is the integration stack appropriate? |
| Precision | Are backlash and stiffness acceptable? |
| Controls integration | Are sensing, driver, and control modes suitable? |
| Structural support | Are radial, axial, and moment loads supported? |
| Thermal capability | Can the joint sustain the required duty cycle? |
| Documentation quality | Can the engineering team integrate it confidently? |
| Commercial readiness | Can the supplier support prototype and production timing? |
| Supply risk | What happens if the supplier slips or becomes unavailable? |
Teams can assign weights to each category, but the framework should remain visible and explicit.
15. Comparison Template for Integrated Joint Suppliers
Use one comparison sheet for all shortlisted candidates.
Comparison template — populate each column using published model-level specifications and confirmed supplier information.
For actual product records, unavailable technical or commercial fields should be shown as:
Not publicly disclosed
Do not infer missing values from another model, family, or supplier.
| Parameter | Supplier A | Supplier B | Supplier C |
|---|---|---|---|
| Product / model | — | — | — |
| Integrated motor | — | — | — |
| Reducer type | — | — | — |
| Reduction ratio | — | — | — |
| Rated torque | — | — | — |
| Peak torque | — | — | — |
| Rated speed | — | — | — |
| Maximum speed | — | — | — |
| Backlash | — | — | — |
| Torsional stiffness | — | — | — |
| Encoder type | — | — | — |
| Output encoder | — | — | — |
| Driver integrated | — | — | — |
| Control modes | — | — | — |
| Bus voltage | — | — | — |
| Communication interface | — | — | — |
| Radial load | — | — | — |
| Axial load | — | — | — |
| Moment load | — | — | — |
| Outer diameter | — | — | — |
| Length | — | — | — |
| Hollow bore | — | — | — |
| Weight | — | — | — |
| Thermal information | — | — | — |
| CAD / drawings | — | — | — |
| Electrical documentation | — | — | — |
| Communication documentation | — | — | — |
| Lead time | — | — | — |
| MOQ | — | — | — |
| Customization | — | — | — |
| Technical support | — | — | — |
16. Decision Rules Before RFQ or Prototype Freeze
Before selecting a final supplier, confirm:
- - Exact engineering fit
- - Documented interface compatibility
- - Acceptable thermal basis
- - Acceptable structural support
- - Sufficient documentation
- - Prototype availability
- - Commercial responsiveness
- - Schedule compatibility
If a candidate is promising but key information is missing, do not force a final decision from incomplete evidence.
Move the missing fields into the RFQ and supplier follow-up process.
17. When to Use Browse, Compare, and RFQ
Use the Robotic Supply workflow in three steps:
1. Browse
Use the catalog to identify integrated joint families and model-level options that broadly fit the application.
2. Compare
Compare compatible shortlisted candidates across published technical fields and visible product information.
3. RFQ
Use RFQ when technical or commercial fields remain open, including lead time, MOQ, documentation requests, customization, or missing performance conditions.
This workflow helps teams move from broad selection to evidence-based sourcing.