Omnidirectional mobile robots with powered caster wheels: design guidelines from kinematic isotropy analysis

Author(s):  
D. Oetomo ◽  
Yuan Ping Li ◽  
M.H. Ang ◽  
Chee Wang Lim
Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 600
Author(s):  
Matthew S. K. Yeo ◽  
S. M. Bhagya P. Samarakoon ◽  
Qi Boon Ng ◽  
Yi Jin Ng ◽  
M. A. Viraj J. Muthugala ◽  
...  

False ceilings are often utilised in residential and commercial spaces as a way to contain and conceal necessary but unattractive building infrastructure, including mechanical, electrical, and plumbing services. Concealing such elements has made it difficult to perform periodic inspection safely for maintenance. To complement this, there have been increasing research interests in mobile robots in recent years that are capable of accessing hard-to-reach locations, thus allowing workers to perform inspections remotely. However, current initiatives are met with challenges arising from unstructured site conditions that hamper the robot’s productivity for false ceiling inspection. The paper adopts a top-down approach known as “Design for Robots”, taking into account four robot-inclusive design principles: activity, accessibility, safety, observability. Falcon, a class of inspection robots, was used as a benchmark to identify spatial constraints according to the four principles. Following this, a list of false ceiling design guidelines for each category are proposed.


2012 ◽  
Vol 132 (3) ◽  
pp. 381-388
Author(s):  
Takaaki Imaizumi ◽  
Hiroyuki Murakami ◽  
Yutaka Uchimura

PCI Journal ◽  
2020 ◽  
Vol 65 (6) ◽  
pp. 35-61
Author(s):  
Chungwook Sim ◽  
Maher Tadros ◽  
David Gee ◽  
Micheal Asaad

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.


2006 ◽  
Vol 65 (3) ◽  
pp. 229-241
Author(s):  
S. F. Yatsun ◽  
F. K. Freire ◽  
V. S. Dyshenko ◽  
O. A. Shadrina
Keyword(s):  

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