From spacecraft and cars to computer chip factories and scientific laboratories, unwanted vibrations can reduce accuracy, damage equipment, and shorten the life of expensive machines.
Now, researchers in South Korea have developed a new type of “smart” vibration isolator that can automatically adjust to different weights while providing better protection against vibrations than current designs.
The research, led by Professor Seunghun Baek from Pusan National University, was published in the journal Mechanical Systems and Signal Processing.
The team believes the new technology could improve the performance of precision manufacturing equipment, robots, aerospace systems, and many other machines that require stable operation.
Vibration isolators are devices placed between a machine and its support surface to reduce the movement caused by shaking or impacts.
Most traditional vibration isolators rely on springs and dampers to absorb vibrations. However, they have an important limitation.
A soft spring can block low-frequency vibrations more effectively, but it also struggles to support heavy loads. A stiffer spring can carry more weight but allows more vibration to pass through. Engineers have long struggled to balance these competing needs.
To overcome this problem, researchers have developed special systems called quasi-zero stiffness, or QZS, isolators. These devices combine ordinary springs with special components that create what is known as negative stiffness. Together, they allow the system to support heavy loads while still reducing low-frequency vibrations.
Although QZS isolators perform better than conventional designs, they also have drawbacks. They must be carefully adjusted for a specific weight, so even a small change in the load can reduce their effectiveness. They also cannot completely eliminate a problem called resonance, where vibrations become amplified instead of reduced.
The research team designed a new solution by combining a QZS isolator with electric motors that continuously adjust the system. Their prototype uses a rhombus-shaped frame connected by four identical links, along with vertical and horizontal springs. Small electric actuators are attached to the structure and can change the tension in the horizontal spring whenever needed.
The system uses two intelligent control methods working together. The first automatically detects changes in the weight being supported and adjusts the spring so the isolator continues to perform properly. This allows the system to maintain its vibration-blocking ability even when the payload changes.
The second control method constantly monitors the movement of the system while it is operating. If vibrations begin to build up, the electric actuators immediately make tiny adjustments that create an opposing force. This helps keep the supported object steady and prevents resonance from developing.
To test the design, the researchers built a working prototype. Their experiments showed that the first control system successfully adapted to different payloads ranging from about 1.01 to 1.21 kilograms while maintaining effective low-frequency vibration isolation. The second control system completely removed the remaining low-frequency resonance when tested with a payload of 1.11 kilograms.
According to the researchers, the new hybrid control strategy solves both major weaknesses of existing QZS isolators at the same time. Instead of requiring manual adjustments whenever the weight changes, the system automatically retunes itself and actively suppresses unwanted vibrations.
The team describes the device as a kind of “smart cushion” that senses changes in its environment and responds in real time.
In the future, this technology could help protect delicate semiconductor manufacturing equipment, improve the stability of scientific instruments, and allow robots carrying fragile objects to move more safely.
By making vibration isolation more adaptive and intelligent, the new system could lead to machines that perform more accurately, last longer, and require less maintenance in demanding environments.
