Document Type : Original Research Paper

Authors

• Yaser Shahbazi ¹
• Hanieh Kouchaki ²

¹ Associate Professor, Department of Architecture, Faculty of Architecture and environmental Design, Islamic Art University of Tabriz, Tabriz, Iran.

² M.A. in Architectur, Department of Architecture, Faculty of Architecture and environmental Design, Islamic Art University of Tabriz, Tabriz, Iran.

Abstract

Extended Abstract
Background and Objectives: The aim of this study is to explore the design, construction, and control of adaptive free-form shading structures that can react to changes in light levels. The focus is on developing a transformable scissor-like structure capable of changing geometry to achieve controlled forms. The key objective is to create an adaptive shading device for a specific courtyard, considering factors such as human interaction, relaxation, and optimal shading conditions.
Methods: The study employed a parametric design approach, utilizing digital tools such as Rhino software and Grasshopper plugin. The design process involved identifying influential environmental factors, defining control objectives, and simulating daylight receiving conditions using the Ladybug plugin. Different forms with varying support points were proposed and evaluated based on aesthetics, shading levels, and site constraints. In this method, the desired free-form surface is initially drawn. Then, the Iso-curves of the surface are extracted along the horizontal and vertical directions to obtain a mesh network of the surface. This mesh network is transformed into a three-dimensional spatial mesh structure, and finally, all the lines of this network are converted into scissor-like modules. It is worth noting that besides using horizontal and vertical Iso-curves, it is also possible to extract inclined, triangular, pentagonal, and multi-sided networks from the free-form surface. Through this approach, various double-layer networks with diverse multi-sided modules can be transformed into scissor-like structures. In the next step, special connections, including rod connections within each scissor-like unit and connections between neighboring units, were designed and labeled for laser cut wood. Control connections were introduced to enable deformation within the fixed span of the structure. The modified scissor-like element model by Akgun was utilized, allowing individual substructures to change independently. Arduino, a microcomputer chip, has gained considerable interest in architecture because of its user-friendly nature and its ability to work seamlessly with a range of sensors and controllers. It facilitates the creation of smart devices by taking input from sensors and switches and producing diverse responses, like modifying light levels, adjusting motor speeds, and controlling other outputs. Arduino can function autonomously or be linked to a computer, and it can be programmed using software such as Arduino’s own IDE or the Grasshopper plugin in Rhino. In terms of controllers, there are various options available, including pneumatic jacks, shape-changing smart materials like shape memory alloys, piezoelectric elements, and electromechanical motors. Servo motors, in particular, are commonly used controllers, especially in small-scale model-making, as they can create rotational motion based on the input voltage received from microcontrollers. 
Findings: Through simulations and analysis, it was found that among the alternatives mentioned in this article, a three-support-point canopy offered the most favorable inactive option, delivering the desired shading conditions for more hours throughout the year. This finding validated the effectiveness of the proposed design approach and highlighted the potential for achieving passive shading without relying heavily on active control. The laboratory-scale prototype demonstrated the feasibility of the adaptive shading model. Sixteen servo motors were connected to eight corrective units, allowing for changes in the angle between rods and structural deformation. Light sensors, Arduino kits, and a closed-loop control system facilitated the processing of sensor data and commanded the servo motors. The prototype successfully achieved controlled structural deformation in response to the presence or absence of sunlight.
Conclusion: The study presented a comprehensive framework for the design, simulation, and construction of adaptive and controllable free-form scissor-like structures. The research showcased the potential of digital architecture and embedded systems in creating dynamic and responsive solutions. By combining sensors, central processing units, and controllers, the suggested design for a shading system allowed for the adjustment of its shape in response to environmental conditions, particularly the movement of sunlight. The findings underscored the significance of considering both passive and active design strategies. While passive geometry and form optimization played a crucial role in achieving desired shading, active control mechanisms provided flexibility and adaptability to changing conditions. The study emphasized the importance of carefully selecting the form, placement of corrective modules, and incorporating various sensors to enhance the capabilities of such structures. In conclusion, this research contributes to the growing field of digital architecture by providing insights into the design and implementation of adaptive shading device. The proposed framework and the laboratory-scale prototype demonstrate the potential for creating adaptive and responsive architectural solutions that seamlessly integrate with their surrounding environment. Future research can explore additional sensors, materials, and control strategies to further enhance the adaptability and functionality of such structures in diverse architectural contexts.

Graphical Abstract

Highlights

- Parametric form-finding of freeform scissor-like structures and simulation of daylight reception.
- Modeling and construction of a small-scale freeform scissor-like shading device. 
- Design and implementation of active control for freeform scissor-like structure to maximize shading.

Keywords

• Adaptive Structure
• Scissors Structure
• Structure Controlling
• Sensor
• Actuator

این مقاله برگرفته از پایان‌نامه کارشناسی ارشد نویسنده دوم با عنوان «فرم‌یابی و پیاده‌سازی سازه قیچی‌سان متحرک دو و سه بعدی فرم‌آزاد و کنترل‌پذیر» می‌باشد که به راهنمایی نویسنده نخست در دانشگاه هنر اسلامی تبریز انجام گرفته است.

This article is derived from the second author`s master thesis entitled “Form finding, construction and geometric control of adaptive freeform scissor-like structures”, supervised by the first author, at Islamic Art University of Tabriz.