Engineers are famous for having a strong do-it-yourself (DIY) spirit, hacking together what may start as inelegant prototypes in the design shop to later become sophisticated, life-changing creations. In the same way, they may want to make their own specialized test equipment to help evaluate and perfect their final products. There are several reasons for going down the DIY path rather than purchasing vendor-made machines including:
Figure 1. Custom, highly configurable solutions may be needed for specialized applications, such as this earthquake simulator at Lehigh University.
Traditionally, brand-name manufacturers for dynamometers, servo-hydraulics and other types of test cells only offer proprietary systems that are inaccessible and hard to customize. If additional features, future upgrades, or servicing is needed, vendors often set high prices for any alternations to their closed systems, leaving customers with the painful choice of living with their limited, existing system or purchasing an entirely new one.
On the other hand, building a custom test system can be an incredibly daunting task. The undertaking will take a lot of time at the very least, and requires expertise in different domains. Also, in order to meet a wide variety of applications, open source options or even COTS tools can sometimes be so generic that it takes considerable effort to customize them for your specific project. Is there any way to have a test system with openness and flexibility, while not spending a substantial amount of time essentially creating everything from scratch?
Test Cell Software Made by Test Cell Integrators
At Wineman Technology, we have decades of experience in the test system integration business, so we understand the challenges and pain points unique to this application space. By building on intellectual property from past projects, we developed the INERTIA test cell development toolkit specifically to save engineers time when creating industrial test machinery with precision control and accurate measurements. This highly configurable, platform-independent, graphical development software makes it easy for test engineers and R&D scientists to quickly and easily streamline development, configuration, and operation of test cell systems with no programming required.
INERTIA is a powerful, sophisticated add-on for NI VeriStand, a real-time test development environment used in a broad range of applications, from embedded software validation to hardware-in-the-loop (HIL) test. INERTIA transforms NI VeriStand into an easy-to-use, vendor-agnostic test cell productivity software specifically designed to streamline tasks such as:
Figure 2. INERTIA graphical test bed software is a platform-independent COTS solution that streamlines the development of automotive, aerospace, medical, and industrial test applications.
How Much Time Does INERTIA Save?
INERTIA development realistically begins after the hardware system is wired together and the software is installed. Below is a high-level, step-by-step description of the test bed development process, with time approximations for each step.
1) Define the System
The first step involves defining and configuring the controller, physical devices, and I/O channels using the project configurator with fill-in-the-blank windows (called the System Explorer).
Estimated Time: one to two hours
2) Define Safeties and Procedures
Before any type of movement or control of machinery can begin, the safety measures must be put in place, using the same System Explorer configuration utility. This step can vary considerably depending on the complexity of the system, from a basic setup with a shutdown procedure and emergency stop, to setup of a full test cell.
Estimated Time: two hours to several days
3) Develop the GUI
After the initial configuration is complete, the INERTIA system definition can be deployed to the hardware and GUI development can begin in the Workspace, a run-time editable user interface that includes many ready-to-use, click-and-drag tools. During this step, you design the GUI’s appearance and verify that the signals are being read and sent correctly.
Estimated Time: one day
4) Set Up Control Tuning
Having open loop control is very common for some types of dynamometers. However, for more complicated test cells, you need to set up the control tuning using the integrated PID tuning tool. Note: if you do not have some experience in tuning or if the control object is complex, please do not attempt this step without assistance. An incorrectly tuned device can cause physical damage to the hardware or bystanders.
Estimated Time: one day
5) Verify and Refine System Level Functionality
As the last step of the system-level setup, you should be able to demonstrate rudimentary control of the physical devices, such as moving actuators or spinning the motor. You may need to go back to the System Explorer configurator to keep refining the system, add more safeties and procedures, and continue fine-tuning the control.
Estimated Time: one to two days
6) Begin Application-Level Setup
Since INERTIA automatically integrates the system configuration with the GUI with the test profile editor (called the Stimulus Profile Editor), a lot of time is saved in the application-level setup. Nevertheless, the time spent in this step depends heavily on the application size and complexity. INERTIA streamlines this step by providing users with their defined test objects already linked into the test profile editor. Creating a test profile simply involves dragging and dropping actions or profile steps into each test object’s window, filling in the appropriate dialog boxes, and even previewing that test profile virtually before deployment.
Estimated Time: one hour to several days
7) Optional: Implement Custom Programming
While INERTIA is a powerful and feature-rich development toolkit, engineers and scientists are always pushing the boundaries and may require some very specific functionality. You can use NI LabVIEW graphical programming to add specialized features. Talk to an experienced engineer at Wineman Technology for help figuring out a workaround to fit your unique application needs.
8) Train the End User
After the test cell has been completed, training may be necessary, since the day-to-day operator using the machine may not be same person who built and set it up in INERTIA.
Estimated Time: one to two days
For a first-time INERTIA user who has a basic understanding of test cells and automation, the system-level setup (described in Steps 1 through 5 below) typically takes three to five days. Setting up a test bed using only NI VeriStand without the INERTIA add-on may take approximately four to eight weeks to customize the features, simply because NI VeriStand is such a versatile development environment designed for many types of applications, not just test cells. In comparison, programming the same test bed from scratch using an open-ended computer language such as C or LabVIEW will take many months, and will probably result in functionality limited to that project.
Full Support from Start to Finish
Going with a ready-made, application-specific COTS software such as INERTIA will give your test bed maximum flexibility while significantly reducing development time.
With INERTIA, you go from a blank definition of a test system to having all the physical devices defined, configuring the test profile, and controlling the system in weeks versus months.
To help you get started, INERTIA comes with a fully featured manual, a complete virtual example, and short video tutorials for addressing specific tasks. Additionally, you will receive one year of free software support (with an option for extended support) so that you have direct access to experienced Wineman Technology engineers. For more information: