8. Soft robotics¶
Bio-Design Soft Robotics with Chameleon Color-Changing Inspiration¶
Bio-design has emerged as a significant field within the paradigm of sustainability, representing a transformative approach to contemporary design practice. The field encompasses diverse methodologies, ranging from designs that utilize scientific knowledge and technologies derived from biology to those employing traditional, handcrafted approaches using local materials and community-based practices (Li & Mooney, 2016). This multifaceted approach reflects the field's evolution from purely aesthetic considerations toward the integration of functionality, utility, and meaningful design value. As bio-design continues to mature, it increasingly emphasizes the exploration of sustainable alternatives in daily life applications, initiates mass production ventures, and prioritizes meaningful design value over material novelty alone (Li & Mooney, 2016).
Soft robotics has simultaneously emerged as a transformative paradigm in next-generation intelligent systems, distinguished by its intrinsic compliance, biomimetic adaptability, and capacity for safe human-environment interaction (Wang et al., 2022). Unlike conventional rigid robotic systems, soft robots leverage compliant materials and responsive technologies to enable adaptive morphology and tunable mechanical properties essential for real-world applications (Wang et al., 2022).
Technologies to enable adaptive morphology and tunable mechanical properties (Wang et al., 2022)
Biological systems, refined through evolutionary optimization across millions of years, exhibit unparalleled multifunctionality in unstructured environments, providing profound inspiration for the development of energy-efficient soft robots capable of environmental responsiveness. This biomimetic approach enables soft robotic systems to achieve safety and adaptability that rigid mechanical systems fundamentally cannot provide, making them ideal for sensitive applications requiring direct human interaction (Ang, Yeow, & Lim, 2023).
Application of responsive soft robotics glove by (Ang, Yeow, & Lim, 2023)
The integration of soft robotics with bio-design principles represents a convergence of multidisciplinary advancement across materials science, mechanical engineering, and computational intelligence. Recent breakthroughs in soft robotics have systematically examined biomimetic actuation mechanisms that enhance efficiency through innovative structural configurations, programmable materials enabling adaptive properties, multiscale manufacturing techniques for fabricating complex structures, and closed-loop control strategies integrating artificial intelligence algorithms (Wang et al., 2022). Simultaneously, bio-design continues to expand its scope toward practical implementation, with recent advances demonstrating the feasibility of soft robotic systems that can be precisely controlled and fabricated using advanced manufacturing techniques while maintaining essential compliance and safety characteristics (Bianchi, Agoni, & Cinquemani, 2023). This synthesis of biological inspiration, material innovation, and engineering precision establishes the foundation for developing adaptive systems capable of responding intelligently to dynamic environmental and user requirements, positioning soft robotics and bio-design as complementary pillars in the future of sustainable, human-centered technological development (Zhu, Zhang, Liu, & Wang, 2025).
Integration of bio design in soft robotics by (Zhu, Zhang, Liu, & Wang, 2025)
Chameleon Biology and Natural Color-Changing Mechanisms: Biological Architecture and Physiological Processes¶
Natural color-changing systems represent some of nature's most sophisticated adaptive mechanisms, evolved through millions of years of environmental pressure to serve critical survival functions including camouflage, communication, and thermoregulation. Chameleons achieve camouflage and expression through sophisticated skin deformation and color change mechanisms inspired by specialized cellular structures, demonstrating a remarkable integration of physical morphology and optical properties. This dual capability of simultaneous shape and color modulation represents a paradigm for bioinspired design, as organisms must coordinate both mechanical deformation and chromatic adjustment in real-time response to environmental stimuli (Jia, 2023).
Source
Biomimetic design has emerged as a transformative methodology in contemporary fashion, systematically integrating the morphological traits, structural principles, and functional mechanisms of living organisms into design thinking. This approach provides both theoretical perspective and practical methodological support for modern design practice, drawing abundant inspiration from nature's aesthetics to achieve a profound fusion of organic form and artistic expression. The evolution of biomimetic design in fashion demonstrates a progression from early direct form-mimicry toward holistic, systems-based approaches that integrate structural principles and ecological considerations. Fashion applications of biomimicry extend substantially beyond simple aesthetic replication, encompassing product development and public installations that demonstrate how biological models drive both aesthetic and functional innovation. Designers employ plant-inspired, animal-inspired, and ecosystem-inspired strategies, each providing distinct pathways for incorporating biological principles while maintaining cultural and aesthetic contexts. This multidimensional approach enables the creation of designs that achieve seamless unity of function and form by combining form simulation with function optimization and ecological awareness.
Chameleon-inspired design exemplifies how biomimetic principles translate directly into advanced wearable technologies. Chameleon-inspired mechanochromic photonic elastomers demonstrate the practical realization of biological color-variation principles, producing flexible materials with brilliant structural colors and stable optical responses suitable for visualized human-machine interaction and real-time motion detection. These materials exhibit superior structural integrity and mechanical stability, maintaining their mechanochromic properties even after repeated stretching cycles, enabling applications in photonic skins and soft robotic systems. The integration of biomimetic design with smart textiles further extends these capabilities, creating multifunctional wearables that combine health monitoring, temperature control, and real-time adaptive responses (Zhu et al., 2025).
Future directions of smart textiles by (Zhu et al., 2025)
The interdisciplinary potential of biomimetic approaches transcends aesthetic considerations, extending into materials innovation, technological integration, and environmental sustainability, offering unique pathways for addressing contemporary design challenges (Zhu et al., 2025). By organically combining form simulation with function optimization and ecological awareness, biomimetic design not only elevates the aesthetic value, visual impact, and emotional resonance of fashion works but also amplifies their social role and cultural significance while advancing sustainable practices.
Design Methodology and Prototyping: Fabrication Techniques, Modeling Approaches, and Iterative Development Processes¶
Design methodology and prototyping represent critical stages in translating chameleon-inspired color-changing bio-design concepts into functional soft robotic systems. The study of soft robotics using sodium alginate and glycerol focuses on developing flexible, biodegradable actuators that mimic the adaptability and movement of living organisms. Sodium alginate, a natural polysaccharide derived from brown algae, forms hydrogels when crosslinked with calcium ions, creating a soft yet stable matrix. Glycerol acts as a plasticizer, improving elasticity and preventing brittleness. This combination results in a flexible film capable of pneumatic actuation. The research explores how varying the ratios of sodium alginate, and glycerol affects mechanical strength, flexibility, and response time. The goal is to create sustainable soft robotic components that can perform bending, gripping, or expanding motions while maintaining structural integrity and environmental compatibility.
References & Inspiration¶
Inspiration¶
The inspiration for this research comes from the color-changing chameleon, a reptile known for its remarkable ability to alter skin color through structural and pigmentary changes. This biological mechanism driven by nanocrystal reconfiguration and pigment redistribution demonstrates how living systems can dynamically adapt to their environment. By translating this concept into soft robotics, the project aims to create actuators that not only move fluidly but also have the potential to integrate color-changing materials or coatings that respond to stimuli such as pressure, temperature, or light. The chameleon’s biological architecture serves as a model for designing responsive, multifunctional materials that combine motion and visual transformation.
References¶
Ang, B. W. K., Yeow, C.-H., & Lim, J. H. (2023). A critical review on factors affecting the user adoption of wearable and soft robotics. Sensors, 23(6), 3263.
Bianchi, G., Agoni, A., & Cinquemani, S. (2023). A bioinspired robot growing like plant roots. Journal of Bionic Engineering, 20, 2044-2058.
Jia, R., Xiang, S., Wang, Y., Chen, H., & Xiao, M. (2023). Electrically triggered color‑changing materials: Mechanisms, performances, and applications. Advanced Optical Materials, 12(10), 2302222.
Kim, S., Laschi, C., & Trimmer, B. (2013). Soft robotics: A bioinspired evolution in robotics. Trends in Biotechnology, 31(5), 287–294.
Rus, D., & Tolley, M. T. (2015). Design, fabrication and control of soft robots. Nature, 521(7553), 467–475.
Wang, T., Zhang, W., & Zhao, Y. (2022). Bioinspired intelligent soft robotics: From multidisciplinary integration to next-generation intelligence. Advanced Intelligent Systems, 4(8), 2200073.
Zhu, W., Chow, L., Ye, D., Qiu, Y., Li, J., Zhang, B., Guo, Y., Jia, S., & Yu, X. (2025). Advances in smart textiles for personal thermal management. Med X, 3(1).
Zhu, H., Zhang, T., Liu, Y., & Wang, L. (2025). Inspired by the growth behavior of plants: Biomimetic soft robots that just meet the requirements of use. Bioinspiration & Biomimetics, 20(2).
Tools and Materials¶
Materials:¶
• Sodium alginate powder: 2 g (Acts as the primary polymer matrix, providing film-forming properties.)
• Glycerol: 1.5 mL (Serves as a plasticizer, improving elasticity and preventing brittleness.)
• Distilled water: 100 mL (Used as the solvent to dissolve sodium alginate and distribute glycerol evenly.)
Tools¶
• Beakers and stirrers
• Molds or 3D-printed grippers
• Blender 5.4.3
• PLA grippers
• Syringe (for pneumatic actuation)
Process and workflow¶
Step 1: Designing the grippers¶
The designed the Gripper with Blender 4.5.3
The gripper sliced for 3D Print
The second gripper used for soft robotics
Step 2: Prepare the flexible film¶
1: Heating the Water: Heat 100 mL of distilled water to approximately 60°C. This temperature helps dissolve sodium alginate more efficiently by reducing viscosity and promoting uniform mixing. Avoid boiling, as excessive heat can degrade the polymer structure.
2: Adding Sodium Alginate: Gradually sprinkle 2 g of sodium alginate powder into the warm water while stirring continuously. Adding it slowly prevents clumping and ensures even dispersion. Use a magnetic stirrer or manual stirring at moderate speed.
Adding Sodium Aligate to the distilled water
3: Forming a Uniform Solution: Continue stirring for 40 minutes until the mixture becomes a smooth, viscous gel-like solution. The solution should appear homogeneous, with no visible lumps or undissolved particles. This step ensures consistent film thickness and mechanical properties.
Mixing the solution for 40 minutes
4: Incorporating Glycerol: Add 1.5 mL of glycerol to the alginate solution. Stir for an additional 10 minutes to ensure complete mixing. Glycerol molecules intercalate between alginate chains, reducing intermolecular forces and increasing flexibility.
5: Degassing the Solution: Allow the mixture to rest for 15 minutes to release trapped air bubbles. For a more refined result, use a vacuum chamber to degas the solution. Removing air bubbles prevents imperfections and weak spots in the final film.
6: Casting the Film: Pour the degassed mixture onto the grippers. Spread it evenly using a spoon to achieve a uniform thickness of 2 mm. The thickness can be adjusted depending on the desired flexibility and strength.
Spreading the films to the prepared mold
7: Drying the Film: Leave the cast film to dry at room temperature for 36 hours. Avoid direct sunlight or high heat, as rapid drying can cause cracking or uneven texture. During this period, water gradually evaporates, leaving behind a solid polymer-glycerol matrix.
Drying the films
8: Peeling and Finishing: Once fully dried, gently peel off the film from the surface. The resulting sheet should be transparent, smooth, and rubber-like in texture.
Step 3: Pneumatic Soft Robotics Testing with Syringe¶
Step 4: Attaching the Air Inlet¶
• Connect the eye let of the film to a syringe
Step 5: Testing Pneumatic Actuation¶
• Slowly push the syringe plunger to inject air into the film pocket.
• Observe the inflation and deformation of the film
• Repeat the process to test durability, elasticity, and response time.
Acknowledgments¶
Special thanks to:
The Fabricademy instructors for guidance on soft robotics principles. The Fablab Rwanda coordinators for their kind guidance and support.
Challenges¶
During the development of the soft robotics prototype, one of the main challenges was the difficulty of obtaining the required materials, particularly sodium alginate and glycerol, at the right time.
Another challenge was the long drying time of the sodium alginate–glycerol mixture.
Overall, these challenges emphasized the need for better material scheduling, environmental control, and process optimization when using sustainable, bio-based materials.