While it is a normal convention to displace objects through mechanical systems, such as wheels or legs, a team led by Professor Daniel Saakes of the Department of Industrial Design has designed a strategy that harnesses vibrations to effectively allow an object to move by itself. They named their strategy “Ratchair”, due to the pieces of furniture moving analogously to a rotating ratchet.
The team designed both external vibration modules that can easily be attached to the legs of furniture and other objects, and furniture with embedded modules. By delivering bursts of vibrations individually to the legs of the chairs or tables, it was able to generate centrifugal forces. Since the forces and movements resulting from the vibrations vary greatly due to a multitude of parameters, such as the properties of the contact surfaces, the team had to understand what type of vibrations caused what type of movements.
For this purpose, they utilized an overhead camera to track the chair and, by systematically applying different amplitudes of vibrations, they were able to produce a catalog of possible translations and rotations. By utilizing this pool and an optimization algorithm, the team computed an efficient sequence of moves which could translate the object from a certain pose and location to another.
A principle such as “Ratchair” could serve a useful function in situations where a large object must be displaced, but lifting or attaching wheels is not a possibility. The team also contemplated its applications in assisting people with restricted mobility, such as the disabled or elderly. Due to the low cost and modularity of the design, the vibration modules could be mass-produced to make a wide assortment of objects mobile.
However, there are some limitations to the design. Testing precomputed sequences, which could previously effectively move an object from one point to another, in different environments leads to undesired outcomes. Whether it be a carpet or a wet floor, changes in the properties of the contact surfaces lead to disparate movement. Essentially, for the system to be viable, it is required to test, analyse and compute new parameters and sequences on every surface the objects might traverse.