Programmable motion controller adds flexibility to testing blowout preventers

A general-purpose test system can be viewed as a research and development tool and a production and reliability support tool. An advanced motion controller allows customers to go beyond design verification to study materials science and design integrity.


Figure 1. The WorxAmerica test system uses a hydraulic cylinder to simulate the action of drill pipe movement through the blowout preventer (BOP). The company’s tester is based on the RMC150 8-axis motion controller manufactured by Delta Computer SystemsIn a fast-moving industry such as the production of equipment for oil exploration, use of general-purpose test stands for quality assurance can deliver long-term benefits. With the inclusion of programmable functionality and test data logging and display, the usefulness of a particular test stand design can extend far beyond its initial design purpose. 

Verification tests

For example, Tomball, Texas, system integrator WorxAmerica developed a test system to verify that a customer's oil well blowout preventer (BOP) product design met American Petroleum Institute (API) standards. The task of a blowout preventer is to center the drill pipe in the oil well, regulate the pressure of fluid in the well hole, and either clamp or cut off the drill pipe to minimize leaks should the pressure exceed a set limit. But beyond proving basic BOP device functionality, the customer is finding that the test setup can just as easily be programmed to do life testing, too. And WorxAmerica suggests that ultimately, the test system (see Figure 1) can be used to test subcomponents, such as the BOP's rubber seals. 

Motion control

Using an easily-programmable and configurable motion platform is fundamental to the versatility of the BOP test system that WorxAmerica built. The company's tester is based on an 8-axis motion controller manufactured according to the API test standard, so the system was designed to measure the amount of fluid leakage past the BOP collar as a simulated drill rod is cycled through multiple down and up strokes at 24 in./sec. for nearly 60 in. of total stroke. The rod is driven by a hydraulic cylinder that has a 6-in. bore with a 3-in diameter rod and is capable of handling 5,800 psi for a total force of 82 tons.

By programming the test system to rapidly move the simulated drill rod (which is crafted with dimensional variations to simulate the changes in rod diameter that the BOP will encounter as rod segments pass through it in the real world) into and out of the BOP, the test system can produce the amount of stress and wear on the BOP in a few hours that the device would normally sustain over a period of years. The motion controller supports the ability for an external PC running data acquisition software to examine parameters during a motion operation, such as the force required to move the drill rod. A change in a key force value may signal that the structures within the BOP device are wearing out. Likewise, if at the end of a "lifetime" of wear, the BOP is still performing to spec, then that is an indicator of the quality of the product. "Previously there was no way to dynamically look at problems that can signal BOP failure," said Chuck Camp, WorxAmerica chief engineer. "There were mathematical models, but there has not been any actual proofing that the model adheres to real life."

Temperature inputs

Figure 2. The RMC150 manufactured by Delta Computer Systems can control up to 8 motion axes. The Delta controller supports the ability for an external PC running data acquisition software to examine parameters during a motion operation, such as the forceThe WorxAmerica test system employs all 8 motion axes of the motion controller (Figure 2). One axis controls the hydraulic cylinder's positions, speeds, and forces exerted. The other seven axes are used for high-speed analog inputs for data acquisition: four pressure inputs from the BOP, two temperature inputs from the hydraulic system, and one connected to a flowmeter to measure leak rate of the BOP. This illustrates the fact that motion axes can be used for parameter monitoring and decision-making, not just for motion axis control. For the WorxAmerica system, control loops are set up in the motion controller to compare external sensor data with setpoints.

The motion controller makes decisions based on the data and can vary how the simulated drill rod is operated as a result. Because the system needs to react very quickly as the rod passes through the BOP, the motion controller was programmed to close the control and monitoring loops of all axes faster than 1,000 times per second. To move the rod at the specified rate, the motion controller commands a proportional servo valve that can deliver varying amounts of hydraulic fluid to enable precise control of the rod motion.

PC-based control software

The motion controller was programmed and tuned by the WorxAmerica team, using motion control PC-based software. With the software tools "we can plot key parameters as we're tuning the system and save them for later review," said Chuck Camp. "The plots clearly show when the gains of the control loops are set correctly." The data interface between the motion controller and an attached PC was handled via the software. This tool enables an external PC to read and write data to and from the motion controller and acquire test data using popular PC-based control software packages.

"A general-purpose test system such as ours can be viewed as both an R&D tool and a production and reliability support tool," said Chuck Camp. The "motion controller will allow our customers to go beyond design verification to study materials science and design integrity." The cost of capable test machines isn't insignificant, and it makes sense to make them work in as many test roles as possible.

- Bill Savela, PE, Delta Computer Systems Inc.; edited by Mark T. Hoske, content manager, Control Engineering,

Key concepts

  • System integrator provides motion control expertise for 8-axis simulation of a blowout preventer.
  • A data interface connected the motion controller and PC.
  • Testing provides design verification and ability to study materials science and design integrity.

Consider this

With more efficient information flow, what can you learn about your processes?  

ONLINE extra

Delta Computer Systems motion controllers 

WorxAmerica technologies 

See a related story by the author on oil-rig pipe testing below.

No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Big Data and IIoT value; Monitoring Big Data; Robotics safety standards and programming; Learning about PID
Motor specification guidelines; Understanding multivariable control; Improving a safety instrumented system; 2017 Engineers' Choice Award Winners
Selecting the best controller from several viewpoints; System integrator advice for the IIoT; TSN and real-time Ethernet; Questions to ask when selecting a VFD; Action items for an aging PLC/DCS
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.
Motion control advances and solutions can help with machine control, automated control on assembly lines, integration of robotics and automation, and machine safety.
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Future of oil and gas projects; Reservoir models; The importance of SCADA to oil and gas
Big Data and bigger solutions; Tablet technologies; SCADA developments
SCADA at the junction, Managing risk through maintenance, Moving at the speed of data
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
click me