Hinged Tile-Based Air Surface for Morphing Windshield Cowling

ASME 2021 Conference on Smart Materials, Adaptive Structures and Intelligent Systems · 2022 · 1 citations

• Computer Science
• Computer Science
• Mechanical engineering

Abstract The gap between the windshield and hood provides an opening for windshield wipers to operate, but can be problematic at other times, gathering leaves and snow. Active morphing approaches provide an opportunity to create a windshield cowling that addresses this issue by covering the gap normally, and actively curling out of the way to allow wiper operation. Most existing morphing techniques lack the simultaneous force/stroke generation, cannot perform two-way actuation, or fail to rigidly hold their position against varying loads such as wind. This paper introduces a useful curling air surface based on hinged T-shaped tiles that improves upon existing morphing technologies by adding straightening actuation to out-of-plane curling with large force and deflection, while also providing rigid position holding. An upper curling bladder encloses the hinged T-shaped tiles and pulls the T-protrusions together when vacuumed, causing the surface to curl. Lower straightening bladders span the hinge lines and pull the tiles flat when inflated. Through vacuum and inflation of the two bladders, the air surface covers and uncovers the gap against the wind load, and can hold its curled position rigidly using inter-tile hard stops. To predict the air surface performance, an air surface model is aggregated from multiple instances of a unit curling model that is derived from first principles with additional phenomenological terms. The validated model enables a scalable dimensionless design space visualization for general curling applications against loads, which is applied to design a windshield cowling. The resulting design is tested with its wind retention ability and built into a full-scale prototype windshield cowling operating on a sedan. This paper provides the technology concept and supporting model and design approach to more broadly apply this useful air surface architecture to applications in automotive (air dam, adaptive seating), aerospace (morphing wing), architecture (self-assembly shelters) and other domains.

Posable Tensegrity-Constrained Inflatable Kinematic Graphical Analysis

ASME 2021 Conference on Smart Materials, Adaptive Structures and Intelligent Systems · 2020 · 4 citations

• Computer Science
• Computer Science
• Artificial Intelligence

Abstract Inflatable devices have been used in various applications due to their low cost, light weight, simplicity, and ability to compactly stow yet deploy to large sizes with complex shape. Recently, soft robotics has added active shape change to inflatables’ otherwise static functionality. However, the required complex multi-chamber structures and active pressure control sacrifice many inherent advantages including simplicity and stowability. Many applications require only passive shape change (posability), where users manipulate a device manually, and the device simply holds its new posed shape. This paper explores a new approach using internal string-like tensile elements to provide posability while maintaining stowability and other inherent advantages of inflatables, leveraging concepts in the field of tensegrity mechanisms. Tensegrity constrained inflatables provide posable motion by allowing internal tensile strings to thread through loops as the shape is changed, where friction between the strings and loops retain the new pose. Graphical instantaneous center kinematic analysis techniques for traditional linkage systems are extended to include threaded tensegrity mechanisms, enabling analysis and design of complex posable tensegrity structures. A simple example prototype implementing bending with 1 DOF, demonstrates posable behavior, quantified in terms of the force required to change pose at different angles and pressures. The resulting bistable behavior is explained using the IC kinematic analysis. The kinematic techniques are also applied to the design of one degree of freedom functional building blocks which combine to create tensegrity configurations providing 2 DOF posability in two and three dimensions which are demonstrated through multiple hardware prototypes. The novel technology and design methods presented in this paper provide a foundation for the development of a class of new user-interactive inflatable devices with posable functionality and deploy and stow capability.