MULTI-AXIS SENSORS

A multi-axis load cell is a transducer capable of measuring forces and/or moments in multiple directions simultaneously. Depending on the design, a sensor may measure two or three force components, combinations of force and torque, or all six components: Fx, Fy, Fz, Mx, My and Mz.

Multiple strain-gauge bridges are arranged on a specially designed sensing element so that each measurement channel responds predominantly to a particular force or moment.

A 6-axis load cell, also known as a six-component force and torque sensor, simultaneously measures three orthogonal forces - Fx, Fy and Fz - and three moments - Mx, My and Mz.

This allows the complete three-dimensional loading state at a measurement point to be determined from a single sensor.

Six-axis load cells are widely used in robotics, aerospace testing, automotive development, motorsport, biomechanics, research and test rigs where forces and moments act simultaneously.

Accuracy depends on design and application requirements, but sensors are engineered to minimise crosstalk and provide reliable load measurements.

Multi-axis load cells can be designed for widely differing force and moment capacities. Importantly, the rated capacity does not need to be identical on every axis.

For example, an application may require a high axial Fz capacity but substantially lower Fx and Fy capacities. Custom design allows the geometry to be optimised around this asymmetric load case rather than oversizing every measurement axis.

PCM can develop multi-axis sensors around the required force ranges, moment ranges, mechanical envelope and overload requirements.

Yes. Multi-axis load cells can be designed to measure both linear forces and moments or torques.

A full six-axis sensor measures Fx, Fy and Fz together with Mx, My and Mz. Alternatively, a custom sensor can measure only the required channels - for example Fx, Fy, Fz and Mz - if the remaining moments are not required.

This can reduce complexity and allow the mechanical design to be optimised specifically for the application.

Multi-axis load cell performance depends not only on the accuracy of each individual channel but also on crosstalk or cross-axis sensitivity between channels.

Non-linearity, hysteresis, repeatability, temperature effects and interactions between simultaneously applied loads should therefore be considered.

For demanding applications, the relationship between channels can be characterised using a calibration decoupling matrix, allowing measured outputs to be mathematically compensated for cross-axis effects.

Crosstalk is the output produced on one measurement channel when a load is applied primarily to another axis. For example, applying an Fx force may produce a small output on the Fy or Fz channels.

Crosstalk arises from the mechanical behaviour of the sensing element, strain gauge positioning, manufacturing tolerances and load introduction.

Good multi-axis sensor design aims to minimise these interactions mechanically, while calibration and mathematical compensation can further reduce their effect on the calculated forces and moments.

Yes. Custom multi-axis load cells can be designed around the required combination of forces and moments, capacities, mechanical envelope, mounting interfaces, stiffness, overload capability and environmental requirements.

This is particularly valuable where the available space or load distribution makes a standard six-axis force and torque sensor unsuitable.

PCM can develop the sensing element, strain-gauge configuration, mechanical interfaces, instrumentation and calibration approach as a complete measurement solution.

Yes. Multi-axis sensors can be designed for demanding industrial, automotive, aerospace and outdoor environments.

Material, environmental sealing, cable construction, connectors and strain gauge protection can be selected according to temperature, moisture, corrosion, vibration and other environmental requirements.

The complete operating environment should be defined during specification because environmental protection can influence both the mechanical and electrical design.

The recalibration interval should be based on usage, loading history, required measurement uncertainty, environmental conditions and previous calibration stability.

Annual calibration is a common starting point, but sensors subjected to high cycle testing, shock loading or demanding environments may require shorter intervals.

Recalibration should also be considered following an overload, mechanical impact, repair or any event that could have altered the sensing element or strain gauge installation.

Yes. A multi-axis load cell can often be integrated into an existing test rig or measurement system to replace or supplement single-axis force measurement.

The mechanical interfaces, available space, load path, required stiffness, number of measurement channels, instrumentation and data acquisition system must all be considered.

PCM can also develop custom sensors where the existing machine geometry does not accommodate a standard multi-axis transducer.