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1. Limits of Extramobile and Intramobile Motion of Cylindrical Developable Mechanisms

   https://doi.org/10.1115/1.4048833  

   Butler, Jared ; Greenwood, Jacob ; Howell, Larry L. ; Magleby, Spencer ( February 2021 , Journal of Mechanisms and Robotics)

   null (Ed.)

   Abstract Mechanisms that can both deploy and provide motions to perform desired tasks offer a multifunctional advantage over traditional mechanisms. Developable mechanisms (DMs) are devices capable of conforming to a predetermined developable surface and deploying from that surface to achieve specific motions. This paper builds on the previously identified behaviors of extramobility and intramobility by introducing the terminology of extramobile and intramobile motions, which define the motion of developable mechanisms while interior and exterior to a developable surface. The limits of motion are identified using defined conditions. It is shown that the more difficult of these conditions to kinematically predict may be treated as a non-factor during the design of cylindrical developable mechanisms given certain assumptions. The impact of toggle positions for each case is discussed. Physical prototypes demonstrate the results. 

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2. Hinges and Curved Lamina Emergent Torsional Joints in Cylindrical Developable Mechanisms

   https://doi.org/10.1115/DETC2020-22049  

   Seymour, Kendall ; Bilancia, Pietro ; Magleby, Spencer ; Howell, Larry ( January 2020 , Proceedings of the 2020 International Design Engineering Conferences)

   null (Ed.)

   Cylindrical developable mechanisms are devices that conform to and emerge from a cylindrical surface. These mechanisms can be formed or cut from the cylinder wall itself. This paper presents a study on adapting traditional hinge options to achieve revolute motion in these mechanisms. A brief overview of options is given, including classical pin hinges, small-length flexural pivots, initially curved beams, and an adaptation of the membrane thickness-accommodation technique. Curved Lamina Emergent Torsional (LET) joints are then evaluated in detail, and a thin-walled modeling assumption is checked analytically and empirically. A small-scale cylindrical developable mechanism is then evaluated with Nitinol curved LET joints.

    

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3. Limits of Extramobile and Intramobile Motion of Cylindrical Developable Mechanisms

   https://doi.org/10.1115/DETC2020-22544  

   Butler, Jared ; Greenwood, Jacob ; Howell, Larry L. ; Magleby, Spencer P. ( January 2020 , Proceedings of the 2020 International Design Engineering Conferences)

   null (Ed.)

   Mechanisms that can both deploy and perform desired tasks offer a multifunctional advantage over traditional mechanisms. Developable mechanisms (DMs) are devices capable of conforming to a predetermined developable surface and deploying from that surface to achieve specific motions. This paper presents new terminology that defines motion of developable mechanisms while interior and exterior to a developable surface. The limits of motion are identified using defined conditions, and it is shown that the more difficult of these conditions may be treated as a non-factor during the design of cylindrical developable mechanisms given certain assumptions.

    

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4. Designing Developable Mechanisms From Flat Patterns

   https://doi.org/10.1115/DETC2020-22445  

   Hyatt, Lance P. ; Lytle, Amanda ; Magleby, Spencer P. ; Howell, Larry L. ( January 2020 , Proceedings of the 2020 International Design Engineering Conferences)

   null (Ed.)

   This paper presents tools and methods to design cylindrical and conical developable mechanisms from flat, planar patterns. Equations are presented that relate the link lengths and link angles of planar and spherical mechanisms to the dimensions in a flat configuration. These flat patterns can then be formed into curved, developable mechanisms. Guidelines are established to determine if a mechanism described by a flat pattern can exhibit intramobile or extramobile behavior. A developable mechanism can only potentially exhibit intramobile or extramobile behavior if none of the links extend beyond half of the flat pattern. The behavior of a mechanism can change depending on the location of the cut of the flat pattern. Different joint designs are discussed including lamina emergent torsional (LET) joints. Physical examples are presented.

    

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5. Hinges and Curved Lamina Emergent Torsional Joints in Cylindrical Developable Mechanisms

   https://doi.org/10.1115/1.4049439  

   Seymour, Kendall ; Bilancia, Pietro ; Magleby, Spencer ; Howell, Larry ( June 2021 , Journal of Mechanisms and Robotics)

   null (Ed.)

   Abstract Cylindrical developable mechanisms are devices that conform to and emerge from a cylindrical surface. These mechanisms can be formed or cut from the cylinder wall itself. This paper presents a study on adapting traditional hinge options to achieve revolute motion in these mechanisms. A brief overview of options is given, including classical pin hinges, small-length flexural pivots, initially curved beams, and an adaptation of the membrane thickness-accommodation technique. Curved lamina emergent torsional (LET) joints are then evaluated in detail, and a thin-walled modeling assumption is checked analytically and empirically. A small-scale cylindrical developable mechanism is then evaluated with Nitinol curved LET joints. 

   more » « less