Laser based micro texturing of freeform surfaces of implants using a Stewart platform

Complex freeform surfaces and structures are increasingly designed and used in the product and building industry due to the advances in mathematics and digital design tools. However, there is still a gap between designing freeform surfaces and fabricating them. The process of preparing freeform surfaces’ shop drawings is complicated, time-consuming, and lacks the mutual understanding among the stakeholders. Computational design and Building Information Modeling (BIM) can serve as a mediator agent for the integration of design goals with the geometric logic of constructability. They can also facilitate creating platforms for designing and evaluating freeform structures. This open-ended qualitative research attempts to develop a systematic methodology for automating the design and construction drafting process of freeform lattice space structure. Solving this complex geometric problem aims to benefit the design for construction and manufacturers and shrink the cost and time of the process. The study employs a 3D computer-aided design (CAD) tool and introduces an algorithm that generates a BIM model. The BIM model contains shop drawings and suggests the specifications of the main elements, such as beams, glass panels, and nodes.

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Ellipsoid Packing Structures on Freeform Surfaces

Computer Graphics Forum ◽

10.1111/cgf.13550 ◽

2018 ◽

Vol 37 (7) ◽

pp. 87-95

Author(s):

Qun‐Ce Xu ◽

Bailin Deng ◽

Yong‐Liang Yang

Keyword(s):

Freeform Surfaces

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Evaluation and Representation of the Theoretical Orientation Workspace of the Gough–Stewart Platform

Journal of Mechanisms and Robotics ◽

10.1115/1.3046137 ◽

2009 ◽

Vol 1 (2) ◽

Cited By ~ 9

Author(s):

Qimi Jiang ◽

Clément M. Gosselin

Keyword(s):

Theoretical Orientation ◽

Robotic Manipulators ◽

Stewart Platform ◽

Closed Region ◽

Leg Length ◽

Fixed Frame ◽

Cartesian Space ◽

Orientation Workspace

The evaluation and representation of the orientation workspace of robotic manipulators is a challenging task. This work focuses on the determination of the theoretical orientation workspace of the Gough–Stewart platform with given leg length ranges [ρimin,ρimax]. By use of the roll-pitch-yaw angles (ϕ,θ,ψ), the theoretical orientation workspace at a prescribed position P0 can be defined by up to 12 workspace surfaces. The defined orientation workspace is a closed region in the 3D orientation Cartesian space Oϕθψ. As all rotations R(x,ϕ), R(y,θ), and R(z,ψ) take place with respect to the fixed frame, any point of the defined orientation workspace provides a clear measure for the platform to, respectively, rotate in order around the (x,y,z) axes of the fixed frame. An algorithm is presented to compute the size (volume) of the theoretical orientation workspace and intersectional curves of the workspace surfaces. The defined theoretical orientation workspace can be applied to determine a singularity-free orientation workspace.

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