HEXAFORCE / ENGINEERING SELECTION WORKSHEET
6-axis force sensor selection
& tool-offset calculator
Calculate the force and moment at the sensor origin. Review candidate model targets, keep missing data visible and send one complete load case to engineering.
1 / ENTER ONE SIMULTANEOUS LOAD CASE
Starting values are an example. Enter forces on the sensor assembly, with tool and sensor axes parallel. Add gravity and dynamic loads to your input if applicable.
2 / REVIEW LOADS AT THE SENSOR ORIGIN
See the moment your tool offset adds
In the example, 100 N along +Z applied 100 mm along +X produces My = −10 Nm, even when the tool-point moment input is zero.
Parallel axes and one rigid-body load case only. No rotation transform, automatic gravity compensation, impact model or combined-load approval is included.
WHAT THE RESULT CAN TELL YOU
Three decisions before requesting a drawing
Check moments as well as forces
A tool offset can create a substantial moment even with zero entered tool-point torque. Review all six components at the sensor origin.
Keep targets and approval separate
Known target conflicts deserve a range or geometry discussion. Missing parameters remain open questions, not a green suitability label.
Request one coordinated evidence set
Carry the calculation with drawings, six-channel ratings, calibration conditions and interface documents into the same engineering request.
METHOD / PARALLEL AXES
Move the load reference, retain its signs
For a rigid tool and parallel axes, the force vector is unchanged. The direct tool-point moment adds to the moment generated by the offset.
F_sensor = F_tool r_m = r_mm / 1000 M_sensor = M_tool + r_m × F_tool D_i = |sensor component_i| × multiplier
The cross product order is r × F. Its components are [ryFz − rzFy, rzFx − rxFz, rxFy − ryFx]. Enter signed components of one simultaneous load case.
The wrench formulation and reference-frame interpretation follow Modern Robotics, section 3.4 ↗. General frame changes also require a rotation, which is outside this tool.
Use consistent units and a defined origin
| Quantity | Input | Meaning | Before using a real sensor |
|---|---|---|---|
| Fx, Fy, Fz | N | External tool-point force in parallel axes | Confirm axes, sign convention and included loads |
| Mx, My, Mz | Nm | Direct couple at the tool load point | Do not enter the same offset-generated moment twice |
| rx, ry, rz | mm | Sensor origin → tool load point | Include the assembled tool/adapter offset |
| Planning multiplier | 1–10 | Absolute net sensor components × chosen allowance | Approve dynamics and overload separately |
SOFTWARE EXAMPLES / NOT CUSTOMER CASES
Reproduce the sign and offset arithmetic
| Example | Force [N] | r [mm] | Direct M [Nm] | Sensor M [Nm] |
|---|---|---|---|---|
| Axial contact, lateral offset | [0, 0, 100] | [100, 0, 0] | [0, 0, 0] | [0, −10, 0] |
| Side contact, tool extension | [0, 50, 0] | [0, 0, 200] | [0, 0, 0] | [−10, 0, 0] |
| Direct couple plus contact | [0, 0, −100] | [0, 50, 0] | [2, 0, 0] | [−3, 0, 0] |
Multiplier = 1 in all examples. Signed cancellation applies only to the stated simultaneous case. Reverse directions and alternate payload orientations can change the demand.
Read each target status literally
| Result | What it establishes | Next decision |
|---|---|---|
| Target conflict | A known requested target conflicts with an entered demand or limit | Discuss a different range, size or installation |
| No known target conflict | No comparison against available targets found a conflict; some inputs may be unknown | Request released ratings and missing parameters |
| Zero load case | The six calculated planning demands are all zero | Define meaningful operating and tare cases first |
HXF entries are planned review targets. The directory contains requested dimensions and four known channel-target sets, with many quantities still unconfirmed. Diameter does not verify bolt patterns, sensor mass does not include every adapter/cable, and an interface name does not establish a tested protocol implementation.
Review the model data and its evidence boundaries ↗Match the interface to your acquisition requirement
| Preference | What to request | What this tool cannot establish |
|---|---|---|
| EtherCAT | Firmware-matched ESI/PDO, cycle time, timestamp and filter latency | Verified control bandwidth from a nominal output rate |
| CAN-FD / RS485 / USB | Physical connector, framing, units, byte order and error handling | Protocol equivalence from connector type alone |
| ROS2 / Python integration | Tested driver release, coordinate frame, signs and timestamps | HXF driver availability or automatic reference-frame transforms |
ROS documents WrenchStamped with a coordinate frame and timestamp ↗. Changing a frame label does not perform the physical wrench transform.
Read the interface review checklist ↗Expand one case into an engineering review
| Missing decision | Consequence | Useful evidence |
|---|---|---|
| Simultaneous loads / reverse directions | Independent channel targets cannot establish a combined-load envelope | Separate load cases, supplier combined-load limits and tool geometry |
| Resolution / filtering | A large-range target may not resolve the smallest useful contact | Noise/resolution at named bandwidth and filter settings |
| Mounting stack / mass | Adapters change offset, clearance and robot-carried mass | Complete assembly drawing, fasteners, cable routing and measured mass |
| Dynamics / overload / fatigue | Static arithmetic cannot qualify impacts or lifecycle | Acceleration/contact history, stop loads and approved limits |
ATI's manufacturer selection guide ↗ separately considers moments, overload, measurement range and resolution. Its model examples are not HXF approvals.
Define calibration and acceptance evidence ↗SELECTION QUESTIONS
Keep the model decision tied to the load case
Does this tool approve an HXF model?
No. It compares one calculated demand against owner-planned targets. Released channel ratings, combined-load limits, mechanical fit and the selected output configuration still need engineering approval.
Which direction does the offset vector use?
r points from the sensor origin to the tool load point. All force, moment and offset components use the same parallel, right-handed axes. Reversing r changes the added moment sign.
Is force applied by the robot or force applied to the sensor entered?
Enter the external force and direct moment on the sensor/tool assembly. An opposite reaction convention reverses the wrench signs. Confirm the sign convention of the real sensor before comparing data.
Can I rotate the tool frame here?
No. Rotate both the force and direct moment into axes parallel to the sensor frame before entering them. The calculator changes the moment reference point; it does not apply a 3D rotation.
Are gravity and impact included?
Only if you include their equivalent loads in the input case. There is no automatic payload compensation or impact simulation. Evaluate alternate orientations, acceleration, emergency stops and contact directions separately.
Why does a model without a known conflict still need review?
Missing six-channel targets, mass or thickness do not constitute evidence of a match. Unknowns remain visible. Even all known targets fitting does not establish combined-load capability or approved hardware ratings.
Does the multiplier establish an overload rating?
No. It scales the absolute net sensor loads in this one case. It is a user planning allowance, not a certified safety factor, dynamic envelope or overload test.
Can I send the full calculation with a CAD request?
Use a result request link. Contact retains the signed inputs, offset, multiplier, six planning demands, space limits and interface in an editable worksheet. You can change the request type to CAD and choose the documents you need.
Method and sources reviewed 1 November 2026. Numerical examples are reproducible software calculations, not measured hardware performance.
Send the worksheet with your drawing request
Use a result link to preserve the complete calculation. Add your robot, original sensor revision, other operating cases and required documents on Contact.