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AxialTQ Technical White Paper Details Comparative Testing

Recently, Interface put together a full comparison of our AxialTQ™ Torque Transducer measurement systems versus a competitor’s system that offers a DIN120, 1kNm capacity transducer. To view the complete details, read the new Interface technical white paper A Comparison of Torque Measurement Systems, authored by Jay Bradley, Interface Electrical Engineering Manager.

Here is a brief overview covering the crucial results of the comparison testing.

About AxialTQ Torque Transducer

Since 2018, the AxialTQ has redefined the category of torque measurement systems in terms of function, accuracy, and customizable compatibility. It’s a must have torque transducer for anyone working to minimize uncertainty when measuring anything that turns. It is specifically designed for the expanding torque measurement needs in fields that include the automotive industry, as well as the aerospace and industrial automation sectors.

At the heart of AxialTQ’s innovation is the rotor and high-precision sensing element technology, which when combined with the electronics component, produces industry-leading accuracy. This product is also fully customizable due to its ability to use simultaneous analog and digital outputs. This is key, as it enables real-time control and data collection. The flexible capability of the stator and output module mounting offers an infinite number of configurations to meet any application needs.

AxialTQ was designed and engineered by Interface in direct collaboration with end-users who shared their wish-lists for operational priorities, user profiles, design specifications, feature preferences, and real-world field challenges they wanted a solution to resolve.

The unique decision to implement an axial gap, as opposed to the industry standard radial gap, means there is minimized concern that the shaft, rotor and stator will make contact, significantly reducing the possibility of damaging the system.

Installation Overview

AxialTQ features a 120° stator coil giving it the ability to be mounted in several different orientations. While the full stator loop of the competing system must be carefully aligned with the rotor. AxialTQ’s large axial gap of up to 6mm and radial gap of up to 12mm also allows for small misalignments or rotor movement. The competing system has a small radial gap of 1mm and ±2mm when installed, providing less flexibility and durability. The stators of both the AxialTQ and the competing system have multicolor status LEDs that indicate proper alignment and data transmission.

Performance Testing and Validation

The tests found that both systems performed well and met their respective operating specifications. Some of the dynamic testing was performed only once due to time constraints. This testing also has a greater uncertainty of measurement because of the test setup.

In this comparison we tested the installation process, as well as performance for the following specifications:

  • Zero balance stability
  • Shunt calibration stability and repeatability
  • Measurement repeatability
  • Measurement non-linearity
  • Measurement hysteresis
  • Axial force crosstalk
  • Zero balance over operating temperature
  • Axial gradient temperature performance

Overall, both systems performed in line with specifications. Areas in which the AxialTQ stood out included change in zero-balance readings, performance in operating temperature ranges, and in the in-house spin testing cycles.

Configuration Advantages

Unlike the competing system, the AxialTQ has one analog voltage or current output, two analog frequency outputs, and a digital serial output which are all active and independently scalable and filtered. This means that by applying different scaling to two different outputs, the AxialTQ can operate like a dual range sensor.

Durability

AxialTQ also has a significant advantage in durability. The large axial (up to 6mm) and radial (typically 12 mm) gaps between the rotor and stator make it highly unlikely that the rotor will contact the stator because of harmonic vibration, torque pulse or some other event. Both the rotor and stator coils of the AxialTQ are fabricated from 0.125in (3.18mm) thick FR4, with any conductors located at least 0.05in (1.27mm) from the edge. If damaged, these coils are easily replaced in the factory.

AxialTQ is innovative alternative to current systems and includes creative solutions to overcome some of the challenges that diminish performance in these systems as well. To learn more about go to our AxialTQ product page.

Additional Resources

Recap of Latest Spin on AxialTQ Webinar

AxialTQ Engine Dynamometer Application Note

The AxialTQ Dynamometer

AxialTQ for Anything That Turns and Needs Testing

Force Measurement Solutions for Mobility Markets

One of the tenets in addressing urban mobility is innovation.  As populations grow around the world, addressing how people get from here to there is part of a challenge and opportunity.  Investments are growing in this sector, as experts and designers look to how to increase efficiency and performance in vehicle markets.

Interface has long been a supplier of test and measurement solutions to industries that play a critical role in mobility, from vehicle manufacturers to infrastructure planners and builders. In our latest case study, we look at some of the innovative ways our solutions are being used to advance technologies and capabilities in transportation.

If something moves, it likely needs force and torque testing for reliability, safety and performance. With the evolving trends in urban mobility, Interface is working with makers and builders of all types of transportation solutions for unmanned vehicles like drones and autonomous vehicles, as well as alternatively fueled and electric vehicles.

READ OUR NEW CASE STUDY: INTERFACE’S CRUCIAL ROLE IN VEHICLE AND URBAN MOBILITY MARKETS

Interface customers utilize our standard and custom products in the vehicle and mobility markets to:

  1. Test the force and torque of components for validation or for design improvements
  2. Integration of sensor technology into a component or product for functional real-time performance data

These products include Interface load cells, mini load cells and subminiature load button load cells, rotary and reaction torque transducers, instrumentation, and accessories. For the growing trends for digital requirements in testing and OEM solutions, our wireless and Bluetooth solutions are commonly used in these markets.  Interface is also frequently engaged on specific customer requests for engineer-to-order products and customized solutions.

Here are four use case scenarios of Interface solutions used in the vehicle and mobility markets:

Brake Pedal Testing

Interface’s Brake Pedal Load Cell BPL-300-C was installed on a brake pedal and then connected to a BTS-AM-1 Bluetooth Low Energy Strain Bridge Transmitter Module, which collects and transmits data to our BTS Toolkit Mobile App. This solution allowed the customer to record and review data from a mobile device while out on a test track. READ MORE HERE.

Drone Delivery Systems

Interface supplied four WMC Sealed Stainless Miniature Load Cells to measure the payload weight and  for the detection of in-motion shifting and uneven distribution of the package weight. As the load cells detect this data, it provides a signal to the propeller to increase RPMs on the propellers and adjust balance and weight distribution inflight. WATCH HERE.

Electric Vehicle (EV) Battery Testing

Compression testing performed on EV batteries is critical for performance and safety. As an EV battery is charged and stores more electrons, it swells. If the packaging housing the batteries does not compensate for this swelling in the design, failure is likely. Interface can supply a WMC miniature load cell. The load cell will measure compression force as a battery goes through charge cycles on a test stand to determine the force given off as the battery swells. This allows our customers to design the proper packaging for the batteries. Read more about the future of EV markets and testing here.

Engine Performance Testing

Force and torque sensors are used with a dynamometer, which isolates the engine’s power output to help quantify its overall performance.  In this application, a  precision SSMF Fatigue Rated S-Type Load Cell is attached to a torque arm to “feels” the torque from an engine loading system. The fatigue rating on the load cell allows it to accurately measure performance for extended cycles. A signal conditioner is used to connect out from the load cell to a computer to ensure clear transmission of data to accurately measure torque being produced by the engine. Engineers analyze power transfer through the data output to tune the engine performance. Check out this engine dynamometer application note here.

Contact our experts to learn more about these types of testing applications, use cases and products used in urban mobility projects.

Dimensions of Multi-Axis Sensors Virtual Event Recap

The Interface ForceLeaders hosted forums are designed to answer frequently asked questions from testing engineers and product designers about new technologies and uses cases. In our recent virtual event, Dimensions of Multi-Axis Sensors, we discussed the considerations for these types of sensors, the test and measurement benefits, products Interface offers and various applications.

Interface recognizes that there are growing demands for multi-axis sensors.  In our hosted event, Interface’s Brian Peters kicked-off the conversation by highlighting benefits and reasoning for the use of these types of sensors, including answering some common questions. We’ve provided a recap of the event below or you can watch the event here https://youtu.be/zua1lvTh488.

What is Unique about Multi-Axis Sensors?

Multi-axis sensors have additional bridges to provide output signals for varying axes or types of mechanical loading. They are designed to measure a multitude of forces and moments simultaneously with a single load cell sensor. Fundamentally similar to other force and torque sensors with strain gage bridges bonded to machined “flexures,” each bridge typically defines a measurement axis. 

There are multiple configurations of 2, 3, or 6-axis options.

  • Axial + Torque
  • Axial + Shear
  • Axial + Moment
  • All 6 degrees of freedom

Should You Use Multi-Axis Sensors?

The largest factor to consider is the accuracy of your test model. In many test applications using standard load cells we often notice side or eccentric load, which can skew your data. While many Interface load cells, particularly mini load cells, have been designed to reject indirect loads, nothing can handle side and eccentric loads quite like a multi-axis sensor. Dedicated multi-axis designs are typically more balanced axis capacity limits with discrete signal outputs. Composite signal outputs are common in 6-axis models.

What are the Benefits of Multi-Axis Sensor Technology?

There are a number of benefits to using multi-axis sensors in addition to accounting for and accurately measuring or rejecting side and eccentric load. These benefits include:

  • Consolidate measurement signals, conserve test space
  • Measure unwanted system crosstalk
  • Quantify reaction loads through test article on “non-measure” side 
  • More successful fatigue testing through setup and load verification
  • More data, more understanding, more complete picture

What Considerations Should Engineer Make When Using Multi-Axis Sensors?

If you’ve made the decision to utilize a multi-axis sensor in your test model, please note the following considerations:

  • System-level loads and geometry
  • Maximum loading conditions
  • Chosen capacity is adequate for measurement loads as well as potential peak or extraneous loads
  • Choosing the right sensor based on primary axis measurements

Interface Multi-Axis Sensor Products

Ken Bishop details various types of multi-axis sensor technology from Interface during the highlighted ForceLeaders event you can watch here.  Interface offers a wide range of multi-axis sensors, including 3-axis, 6-axis, axial torsion and 2-axis versions. The product options give you the ability to measure forces simultaneously in three mutually perpendicular axes, with the 6-axis load cells also measuring torque around those axes.

AXIAL TORSION LOAD CELLS

Interface’s axial torsion load cell is used for measuring both torque and force in a single sensor. Typical applications of its axial torsion transducer include bearing test and material test machines. The features of our axial torsion load cell include minimal cross talk, extraneous load resistance, and the load cell is fatigue rated. Customers can also add the following options: an integral cable, compression overload protection, and connector protectors.

2-AXIS LOAD CELLS

The Interface 2-Axis load cells can measure in two directions, X and Y simultaneously. It is commonly used in applications where dual-axis measurement is important in design and testing. They are effective for applications that measure lateral forces and the narrow design fits into compact areas.

2-Axis Interface Products:

3-AXIS LOAD CELLS

Interface’s 3-axis load cell measures force simultaneously in three mutually perpendicular axes: X, Y, and Z – tension and compression. Each axis provides a unique mV/V output and requires no mathematical manipulation. The 3-axis load cell is built to minimize eccentric loading effects and crosstalk between axes. We offer five different models in its 3A Series 3-axis load cell designed for a wide variety of capacities. They are compact in size, provide 3 full bridge mV/V outputs with an IP68 option.

3-Axis Products:

6-AXIS LOAD CELLS

Interface’s 6-Axis Load Cell measures force simultaneously in three mutually perpendicular axes and three simultaneous torques about those same axes. Six full bridges provide mV/V output on six independent channels. A 36-term coefficient matrix is included for calculating the load and torque values in each axis. An 8-channel amplifier with a USB PC interface is also available which simplifies data analysis. The company offers five different models of 6-axis load cells for a wide variety of capacities. In the end, they provide more data, accuracy, are very stiff and cost-effective for a wide range of testing options.

6-Axis Products:

Keith Skidmore, an application expert at Interface, outlined a number of use cases spanning across multiple industries. They included testing programs using multi-axis sensors in automotive, medical, aerospace and defense, consumer packaging and more. Some of the application notes discussed during this recorded event include:

  • Wind tunnel testing
  • Aerospace structural and fatigue testing
  • Computer model validation
  • Friction testing
  • Medical device: ball socket testing
  • Prosthetics
  • Robotic arm
  • Hydrofoil
  • Seat testing
  • Center of gravity

Be sure to watch the YouTube video below to gain insight into some of the most frequently asked questions about multi-axis sensors.

We had a great time introducing our audience to the possibilities of Interface Multi-Axis Sensors. If you are interested in watching the video on demand of the webinar, you can click on the link below to watch the presentation in its entirety.