October 2017

Providing reliability of components to customers with the MANTIS Maintenance Architecture

Goizper S. Coop., smart components’ manufacturer

Goizper S. Coop’s products are mechanical components (clutch brakes, gear boxes, indexing units…) installed within different kind of productive machines. These machines are designed to produce continuously and unplanned downtimes generate high costs. These components are the key part of some of the mentioned productive machines and the relevant component’s health influences directly within the machine status.

Clutch Brake Component located within a mechanical press machine

Breakdown of Components

Furthermore, if one of these components fails, it takes a long time while a new one is sent to the customer’s facilities, removed the old one and set up the new one. In these cases, the production asset maintenance means lot of expenses for customers and suppliers.

MANTIS for predictive maintenance

MANTIS platform provides an online and future view of these components’ health. Smart sensors installed at the mechanical component are connected to Monitoring and Alerting, which is performed automatically, within the smart-G box located next to the mechanical component. Then, this Big Data is processed in the Cloud and through different Maintenance data analytics the status and future trend of the component health is obtained as an output.

Smart-G box and rotary union with sensors

Obviously, the introduction of this Cyber Physical System will not eliminate all machine breakdowns, but it will help in order to reduce considerably machine unplanned downtimes, so that the customer and supplier will be able to plan their maintenance tasks and reduce these kind of stops.

MANTIS Collaboration

Within the MANTIS ECSEL project, Goizper has collaborated close to one of its customers, Fagor Arrasate, trying to improve the real inconveniences and reduce expenses that unplanned downtimes cause in both firms.

Detecting usage on Compact Excavator with ILIAS NVO

Introduction

Compact Excavators are often rented on an hourly or daily rate. No meters are used, which means that for billing only calendar hours or days are used. For maintenance, the system has an “engine hour” meter, but this gives indicator only when the system is running (idle or driving or operating).

The machine used in the test, a Compact Excavator

A proposal is to introduce other meters for more precise counters on the actual use of the machine. One sensor is proposed for the solution, which provides a very cheap way of getting much more usage data.

Business case

For the rental case a “power by the hour” rate could be more efficient. I.e. the end customer pays for the required usage or wear of the machinery and not just number of hours the machine is reserved. It would give a more fair pricing model, since the real cost of running the machinery is mostly due to maintenance. This would give the user an incitement of taking care of the machine while using it. It also gives a better way to estimate the need for maintenance or to balance out the usage of equipment.

For other cases, a simple sensor could give benefits of getting higher fleet availability, lowering operating costs etc. by doing the following:

  • Machine health and how to predict asset failure (predictive maintenance)
  • Prevent or detect abuse
  • Provide data for warranty models
  • Provide data for fleet management/optimization

All of the above mentioned points can be addressed with a simple and robust IMU.

Proof of concept thesis

For this proof of concept, we will provide a thesis, to test the data collection and analytic capability of such a system:

“We believe that we can measure how many hours a hammer and tracks / undercarriage has been used on a compact excavator by measuring the vibration pattern”

The hydraulic hammer mounted on the Compact Excavator

As proof of concept we want to be able to detect the following states

  • Engine Off – ID 4001
  • Idle – low RPM ID 4002
  • Idle – High RPM ID 4003
  • Driving – Turtle gear ID 4010
  • Driving – Rabbit gear ID 4011
  • Driving – Slalom ID 4012
  • Hammer – ID 4020

Other states (such as abuse or hard usage) could also be detected.

The Machine Learning approach

A single IMU sensor is installed in the frame of the vehicle. Data is collected with high resolution and high sampling frequency. Data was collected on a small embedded device in the vehicle.

Model creation data

A series of tests with beforementioned states were made. The data was labeled with each state.

After data labeling, a decision tree was created using statistical features of the data.

The decision tree can now be applied to data collected in real time, on the embedded device.

Test results

A new series of tests were made. This data was again labeled with each state. Data was collected and parsed with the decision tree generated with the model data from before (with fixed data chunk sizes).

In the figure below, the results from the algorithms can be seen.

Visualization of the test results

On the top row of bars, the data labels (the truth) are seen, colored. In the next row of bars, the detected states are colored. The bottom graph is a visualization of part of the collected raw data.

As seen, the colors match with very high precision. Only in the beginning and end of the states there are small errors. This is most likely because of the data labeling (i.e. as the labels were created manually with a stopwatch they may not be completely timely)

Test conclusion

The IMU sensors and embedded device mounted on the Compact Excavator is able to provide data for machine learning and recognition of at least 6 different usage patterns:

  • ignition
  • idle
  • slow driving
  • fast driving
  • slalom driving
  • hammering

The usage information can now be collected, and a “power by the hour” renting concept can be introduced. For example, the renting company can provide an app where the customer can specify how much hammering they want, and how much driving etc. Then a much lower price can be provided. If data is collected and transmitted through GSM, the app can even update in real time, showing usage data.

This means that the operator of the vehicle can in real time see how much usage has been spent. A warning could be provided when i.e. when 80% of the hammering hours have been spent, similar to traveling with a mobile phone abroad and there is a fixed number of Megabytes available.

Perspective

The whole setup was made within a few hours. Mounting of the system took 30 minutes, collecting model creation data took 1 hour. Creating the models took 30 minutes. And testing the system took another hour. We started in the morning, and before lunch time, everything was mounted, calibrated and validated and ready for use.

This sensor and embedded system provides a very easy way of providing actual and valid usage information on mechanical systems.

It can easily detect more states. The meters provided could also be summarized, which could be used to provide the operator with information on when it is time to replace the hammer – before it actually breaks. The time saving from this alone are enough to pay for the system.