Unmanned Systems Technology 015 | Martin UAV V-Bat | William Sachiti | Sonar Systems | USVs | Desert Aircraft DA150 EFI | SeaCat AUV/ROV | Gimbals

75 Electronic image stabilisation software is improving all the time, and while it is not yet a substitute for electromechanical stabilisation, it is reasonable to expect that its performance will be taken into account for any trade-off against the specification of the electromechanical system when engineering a complete stabilised payload to meet a specification. Future directions The gimbal as we know it could be about to undergo radical change as a result of a patented ‘gimbal-less’ technology with semi-active isolation. Consisting of a six- axis ‘flex pivot isolator’ array, it replaces gimbal bearings, constraint structure and passive isolation with what is described as simpler, direct structural support for the payload, and features an active drive system. Multiple isolators are mounted between the support frame and the optical platform inside, and each isolator allows movement along three translational axes and three rotational ones. Rotational movement is free, but the system provides some resistance to translational movement, and the undamped natural resonant frequencies in translational and rotational movement are engineered to be as far apart as possible. The isolators could be springs, flexures or diaphragms. The springs could be machined multi- start helical compression types with their axes radiating out from a common point at the centroid of the platform’s mass. In the flexure system, each element would consist of three, single-axis flexural pivots arranged in series, each with its own axis that meets the other platform’s mass centroid. They would be arranged symmetrically to form an array. With the diaphragm-based Gimbals | Focus Unmanned Systems Technology | August/September 2017 This ‘gimbal-less’ platform is fitted with coil spring isolators to form a six-axis pivot isolator array that allows free rotational movement and damping of linear translational movement (Courtesy of PV Labs) The relative positions of six single-axis voice coil actuators and pivot isolators in an example of stabilised platform technology with an active drive system controlling six axes (Courtesy of PV Labs)