Delta test rig

Test Lab Gets It Wrong—On Purpose!

Nov. 8, 2018
Dealing with the problems of an underdamped hydraulic cylinder test rig.

When you need to achieve precise motion and position control, electrohydraulic experts stress placing the servovalve or proportional valve as close to the cylinder as you can, and to use a manifold or steel tubing to connect the two. You should avoid using hydraulic hose in this situation because the hose’s flexibility is a source of positioning error as pressure increases and decreases.

Another shortcoming in hydraulic system design is using a cylinder with too small a bore. In doing so, system designers figure that increasing the operating pressure of the system will provide the cylinder with enough force to move and position the load.

Delta Computer Systems, Battle Ground, Wash., addresses these common issues and more in its newest lab. Trainees can experience the challenge of tuning an underdamped system and to learn how the advanced control algorithms in Delta’s RMC motion controllers can make it possible.

This test rig at Delta Computer Systems exhibits intentional flaws in hydraulic system design and demonstrates to users how Delta’s RMC Tools and Tuning Wizard features found in their RMC motion controllers can help overcome less-than-ideal control conditions.

Intentional Issues

The lab’s test rig features several elements that make it particularly instructive. The cylinder is deliberately undersized with a bore of only 1 in. for the designed load and acceleration. It also has a longer stroke—10 in.—than recommended for a cylinder with that small a bore. System operating pressure is 1,500 psi, and the rig’s load mass (420 lb) can be adjusted by adding or removing steel plates from its load sled. Position feedback is provided by an externally mounted magnetostrictive linear-displacement transducer. The LDT had to be mounted externally because the 1-in. cylinder did not afford a space large enough to accommodate internal mounting.

Motion is controlled by a high-response electrohydraulic proportional directional valve. The test rig also lets trainees install conduits between the servo-quality directional valve and cylinder ports using short sections of rigid pipe or tubing or long lengths of flexible hose. By shifting a few ball valves, trainees can switch between the 7 in. of hard-piped connections or 6 ft of hose connecting A and B valve ports to the head- and cap-end ports of the cylinder. As a result, the dramatic impact of increasing the volume of trapped oil is made obvious using Delta’s RMCTools Plot feature. Trainees can then use the RMC motion controller's Tuning Wizard to try to adjust the controller gains using first- and second-order tuning algorithms.

Thanks to Aaron Heinrich and Jacob Paso, of Delta Computer System for providing details on this setup.

Continue Reading

Handbook Simplifies Advanced Aspects of Mobile Hydraulic Controls

May 10, 2017
Author Brendan Casey lays out his hydraulics know-how that he acquired over 27 years in a simple handbook made for people that want to improve their skills in troubleshooting ...

Streamlining Wire Harness Manufacturing with a 5-axis Robot

Nov. 28, 2023
The CY1000 robot reduces the manual labor required for production of wire harnesses, helping to address manufacturing and supply chain challenges.

Sponsored Recommendations

MONITORING RELAYS — TYPES AND APPLICATIONS

May 15, 2024
Production equipment is expensive and needs to be protected against input abnormalities such as voltage, current, frequency, and phase to stay online and in operation for the ...

Circuit Protection Devices & Busbars

March 13, 2024
With experienced Product Engineers and Customer Service personnel, Altech provides solutions to your most pressing application challenges. All with one thought in mind - to ensure...

All-In-One DC-UPS Power Solutions

March 13, 2024
Introducing the All-In-One DC-UPS, a versatile solution combining multiple functionalities in a single device. Serving as a power supply, battery charger, battery care module,...

Motor Disconnect Switches

March 13, 2024
With experienced Product Engineers and Customer Service personnel, Altech provides solutions to your most pressing application challenges. All with one thought in mind - to ensure...