MR Fluid (MRF) & MR Powder (MRP)

The smart materials allowing us to create haptic feedbck

MRM (MR materials or magnetorheological materials) are smart materials consisting of fine, magnetizable particles (typically iron) whose rheological properties change through the application of a magnetic field.

This change occurs in less than 0,5 milliseconds, more than 200 times faster than the blink of an eye. Once the magnetic field is removed, the MRM reverts to its unlinked state.

The characteristics of MRM

Fully adjustable & incredibly accurate

The degree of change the MRM undergoes when exposed to a magnetic field is related to the magnetic field’s strength. The stronger the magnetic field, the higher the yield stress of the material. Therefore, the MRM’s level of stress resistance can be controlled very accurately by varying the magnetic field’s intensity. The high level of control over the MRM is the key to our technology’s flexibility and accuracy. Its fast response time allows us to switch between haptic patterns in perfect sync with your user interface, making the operation simple, safe, and intuitive.

Even though MR materials are new to most people, MR technologies have proven themselves for over 20 years in the automotive industry in suspensions or steering systems.

How it works RHEOSHOX Technology

The graph illustrates, how, with increasing strength of the magnetic field (kA/m), the yield stress of the MR fluid increases as well.

Yield Stress vs. Magnetic Field Strength

Carefully selected

for impressive haptic feedback

For our HAPTICORE technology, we use both MR Powder (MRP), magnetorheological powder, as well as MR Fluid (MRF), meaning magnetorheological fluid, a mixture of MRP and a carrier fluid (e.g., oil or glycol). Based on our many years of experience, we test different MRM variations to generate haptic feedback tailored to the specific use cases of our HAPTICORE encoders.

After using MR Fluid for many years, we have since developed our haptic technology further and for certain applications also use pure MR iron powder. While the operating principle of MRF and MRP is the same, the use of different variations of the smart materials allows us to tailor factors such as base torque precisely to the customer’s requirements.