With respect to passive component of the stabiliser, the literature was not rich in terms of our specific application, but instead offered much resources in the related fields. Most of these – from car suspension systems (Abid, et al.) to earthquake-mitigating infrastructure (Ubertini et al.) – used some variant of a damped-spring system. The issue with these was the requirement of an additional mass to provide inertia within the damping system, where the effectiveness of stability usually requires a relatively large mass. As a suspension system with a lower weight can be more convenient for drones and personal use, a novel device that achieves a similar purpose without much additional weight was very welcome.
The inerter – first conceptualised as a mechanical analogue of a capacitor – converts linear motion into rotational (moment of) inertia, hence resisting acceleration between the two nodes of the device, with the benefit of being less massive than an equivalent mass. Furthermore, the effective “inertia” is tunable by changing the gear ratio of the components.
- Input/Output – either ports will be connected to the components whose motions we wish to decouple: in the case of our stabiliser, one side will be attached to the platform, and the other to the handle
- Rack & Pinion – converts linear motion into angular motion
- Flywheel – provides the moment of inertia
Feasibility
The main use of this is to provide a term in the motion proportional to the force in a smaller package, which would fit very well in our system. Furthermore, a gearbox-like mechanism can be implemented, such that its adjustment allows for a much larger variety of camera masses (since the inertia of the stabiliser should be in the same order of magnitude as the camera).