• smart fluids
• magnetorheological fluids
• permanent magnet
• haptic device
• haptics
• finite element analysis
• applied electromagnetism

Studies on haptic devices are acquiring much importance due to the widespread inclusion of the sense of touch in human-machine interaction.
Haptic interfaces excite both tactile and kinesthetic senses, enabling a user to be in contact with an object in a real or virtual environment.
Unfortunately, many existing haptic devices use classical actuator technologies, and so there are challenges associated with minimizing friction and creating high stiffness while achieving a high-force bandwidth and dynamic range.
Recently, interest is growing around a new class of devices based on Smart materials, such as Magnetorheological Fluids (MRFs), that exhibit the ability to significantly change one or more of their properties when excited by an external stimulus, as a magnetic field. They could be used in many applications (e.g., industry, health-care, and entertainment) to reduce the gap between the currently available technologies and the requirements for high integration of human-machine cooperation.
Taking into account the results achieved with other MRF-based haptic devices developed at the University of Pisa, this interdisciplinary thesis aim is to develop a new haptic display (HBB-PM) that excites the MRF with an external magnetic field produced by permanent magnets (PMs). The magnetic field in the MRF can be controlled by varying the distance between the base of the box that contains the fluid and the PMs.
Some magnetic simulations, using a finite element (FE) model, are provided to predict the magnetic field distribution and the trend of the force that has to be developed by the actuators that will move the PMs.
Then, some preliminary validation tests that will assess the efficiency of the FE model are presented, and that will be executed on an existing reduced scale prototype of the device.
Finally, some psychophysical tests are discussed to test the haptic performance of the display.
This work has been realized within the framework of the MIT-UNIPI project, and it has been partially developed in the MIT BioInstrumentation Laboratory (BI Lab).