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An actuator specification must connect delivered motion and force to the feedback signal under the actual machine load. Motor rotation, gearbox output, driven-member position and resistor-card output can diverge because of compliance, backlash, stops or coupling damage. The interface record makes these coordinates and their ownership explicit.
System boundary
Machine command and power through actuator drive, gearbox, linkage, driven member, feedback contact, resistor card and controller input
System integration decisions
- Choose the driven-member coordinate used for functional acceptance.
- Define load and duty over the entire stroke.
- Separate drive control, feedback acquisition and machine-safe response.
Define all motion coordinates
Name motor, gearbox, actuator output, driven-member and wiper coordinates with units, origins and positive directions. Identify which coordinate controls acceptance. A motor encoder does not prove the external member has moved when a coupling or gearbox fault is credible.
Provide the transformation and tolerance between coordinates. Include installation adjustment, mounting stack and stop locations. Record reference direction because backlash can shift the relationship after reversal.
Describe force and load over travel
Supply axial or radial load, torque, side load, gravity orientation, process reaction and seating force versus position. Include breakaway and running loads rather than one peak number.
State speed, acceleration, reversals, dwell, holding time and cycle distribution. Mechanical duty controls heating, wear and feedback exposure. A convenient bench cycle cannot replace the installed profile.
Create a position-resolved load map for the most demanding directions. Include transient impacts and sustained holding separately. If process force depends on temperature, pressure or tool wear, attach those states to the load record. The control team can then distinguish a legitimate rise in drive effort from friction growth or an obstruction.
Calculate usable feedback span
Let B=x_open-x_close define the released driven-member span. Map both endpoints into wiper travel and reserve contact distance for tolerance and overtravel. Do not use electrical saturation to create a mechanical stop.
If open and closed references are 118 and 8 millimetres, B is 110 millimetres. This example defines subtraction only. Actual datums, reserve and acceptance arise from the approved machine and actuator drawings.
B = x_open - x_close
- B: driven-member functional span
- x_open: released open reference
- x_close: released closed reference
Both coordinates share the same datum, load state and direction convention.
Control mounting and reaction loads
Specify flange, fasteners, pilot, brackets, alignment, allowable distortion and reaction path. A compliant bracket can consume travel and change the feedback relationship while the actuator itself remains repeatable.
Define cable routing, bend reserve and connector support through motion. Prevent the harness from applying variable force to the sensor or becoming the unintended travel stop.
State tightening sequence, allowable shim, surface flatness and installation access. Record the reference after assembly because bracket distortion or an offset clevis can shift both useful stroke and side load. Service replacement must reproduce the same datum rather than recalibrating around an installation error.
Specify drive and feedback electrical interfaces
Provide motor supply, drive method, current limit, braking, holding and de-energized behavior. Separately document feedback excitation, return, terminals, input impedance, sampling and filters.
Describe startup, homing, manual jog, automatic motion, emergency stop and restart. State whether feedback remains powered and valid in every state. Machine safety decisions remain with the integrator.
Locate disagreement along the actuator chain
Capture command, motor current, gearbox coordinate, driven-member reference, wiper coordinate and raw feedback together. A current rise with no external movement differs from an electrical dropout at continuous motion.
Use the first inconsistent interface to guide investigation.
| Signature | Boundary challenged | Comparison | Action |
|---|---|---|---|
| Motor turns, output fixed | Gearbox or coupling | Motor and output coordinates | Inspect transmission |
| Output moves, member lags under load | Mounting or linkage | Load and dual position record | Review compliance |
| Member moves, feedback freezes | Wiper or track | Wiper coordinate and terminals | Inspect sensing interface |
| Raw feedback correct, command oscillates | Control logic | Raw and processed signals | Review tuning and filters |
Define stall, jam and power-loss behavior
Identify maximum credible stall duration, current limiting, temperature observation and mechanical consequence. A jam can leave feedback plausible while force continues to build.
State de-energized movement, brake release, stored-energy and restart behavior. Diagnostics, guarding and safe state are machine-system responsibilities and require their own validation.
Define the evidence that distinguishes a mechanical jam from a failed feedback channel. Motor current, output motion and raw position must share a time reference. If an operator can clear a fault manually, specify isolation, retained energy and the conditions checked before automatic commands are re-enabled.
Validate the installed load cases
Exercise full travel, reversals, low and high speed, declared loads, hold, stall protection and power transitions. Use production-intent mounting, linkage, harness and controller settings.
Synchronize mechanical references and electrical nodes. Freeze travel, force, following-error, continuity, uncertainty and retest criteria. Results do not establish lifetime, production capacity or safety certification.
Confirm performance after thermal stabilization and after representative reversal sequences. Reserve assemblies not used for tuning to verify limits. Report the load fixture, alignment, firmware and learned parameters with the trace, because a result without the complete installed configuration cannot support a later change comparison.
Close the actuator coordinate chain with a loaded sweep
Run slow extension and retraction sweeps while recording actuator command, motor or pneumatic input, independent output position, applied force, feedback voltage and converted controller value on one timebase. Hold at selected coordinates to reveal compliance and drift. Repeat near both mechanical limits without allowing the feedback element to become a stop. Directional separation identifies backlash or friction; load-dependent offset indicates structural compliance; a controller-only discrepancy directs review toward acquisition or scaling. Preserve the actual mounting bracket, linkage and harness configuration with the record. The machine owner defines positional, force and safe-state acceptance, while the passive feedback requirement remains tied to its drawing and installed electrical circuit.
Link revisions across mechanics and control
Tie actuator, gearbox, bracket, linkage, stops, wiper, track, harness, drive and software revisions. Revalidate after changes that affect travel, stiffness, force, timing or scaling.
Treat unintended motion, false position, delayed stop and thermal overload separately. Assign mitigation and acceptance to the machine owner; unresolved loads remain open application data.
RFQ inputs for industrial actuation
Submit machine geometry, coordinates, stroke, loads, speed, duty, mounting, stops and linkage. Include wiper travel, resistance curve, terminals and harness.
Provide motor drive, feedback acquisition, control modes, abnormal states, environment, validation, quantities and owners. Identify required machine or regulatory constraints explicitly. Record operator access assumptions.
Include service replacement procedure, homing method, permissible field adjustment and the configuration record required after commissioning.
Industrial actuator interface inputs
Provide the loaded motion chain and feedback architecture together.
- Coordinates, stroke, load, speed, duty, stops and mounting.
- Gearbox, linkage, wiper travel, card curve and harness.
- Drive supply, control modes, feedback acquisition and filtering.
- Stall behavior, validation, environment, quantity, maintenance access, commissioning records, spare-part compatibility and named risk ownership.
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