The need for durable but flexible machines in the fast-paced world of robotics has never been higher. The traditional rigid robot is great in a controlled environment but do not have the flexibility to adapt and be safe around humans, while the soft robot can provide compliance and resistance to most sudden shocks but does not have the required strength and durability to continue working for prolonged times. The recent development of novel soft and hard bonding board concepts is starting to fill this gap by combining the advantages of soft and hard robots to achieve multifunctional, durable and flexible robots to autonomously perform complex tasks in dynamic environments. This progress is creating new applications in health-care, manufacturing, and exploration, where robots need to be able to deal with physical stress but also need to be able to manipulate materials. Researchers are bringing new capabilities to new machines by fusing material science and robotic design.
The idea of bonding soft and hard components is not very new and is borrowed from nature, the biological system where soft (muscles) and hard (bones) components cooperate smoothly, thus offering great prospects. Over the past few years, disruptions in material engineering and fabrication techniques have led to considerable accelerations in the field, with devices capable of producing high-strength, integrated components at multiple scales. This article provides an overview of the important features of these novel solutions, their role in improving robotic performances, the materials and technologies employed, as well as their applications. Upon considering these aspects, soft and hard bonding boards take shape, not as a small step improvement but as a paradigm shift to develop a more competent and reliable robot.
Material Integration and Compatibility
Material integration is the key challenge behind the adoption of innovative soft and hard bonding board solutions. Examples include soft materials (silicones, elastomers, and hydrogels) that add flexibility and shock absorption, and hard materials (metals, ceramics, and rigid polymers) that provide structural support and load-bearing capacity. The challenge lies in the clear bonding of these dissimilar materials to avoid delamination, a local stress concentration, and failure under cyclic loading. Strong and durable interfaces have become possible owing to advances in adhesive technologies, including pressure-sensitive adhesives, covalent bonding agents, and mechanical interlocking designs. These include the development of hybrid composites in which microstructures on rigid surfaces are used to promote bonding with soft matrices, similar to biological attachments between tendon and bone [41 ].
Furthermore, material compatibility is not just about mechanical properties but also thermal, electrical, and chemical properties. Bonding boards must both conduct and insulate in places for robots that need embedded electronics. It makes use of conductive polymers or conductive wiring embedded within soft layers, so it can still work even if it allows flexibility to an extent. 3-Compatibility also meaning that they should not break down when in contact with environmental such such as moisture, uv or high/low temperature. By subjecting material combinations to most insane tests as well as extensive simulation, engineers can then pick and optimise pairs of materials that work in harmony together, making boards supporting functionality over time and with a wide variety of operational conditions.
Manufacturing Techniques and Fabrication
Soft and hard bonding boards are produced by creative manufacturing methods that consider the different characteristics of each. These integrated structures defy traditional means of forming, such as injection molding or machining; integrated structures also lend themselves to additive manufacturing, layered assembly, and multi-material 3D printing. This precise material composition control can lead to the design of gradient or patterned interfaces that outperform conventional laminated structures in stress transfer and bendability. For instance, UV-curable resins and flexible filaments for 3D printing can create soft, stiff, and monolithic parts without separate bonding steps and hence, weak links.
Along with additive processes, you also use laser cutting, vacuum forming, and solvent welding to customize boards for a given end application in robotics. Composite boards with improved damping properties and toughness can be produced using layered fabrication in which steps of soft and hard layers are stacked and bonded by using temperature or pressure. In addition, improved microfabrication and nanotechnology allow for the embedding of functional features in the bonding substrate, such as sensors or actuators [8]. This internalising minimises assembly, lowers weight, and increases reliability, enabling the production of bespoke solutions from surgical robots to industrial automata.
Performance Enhancements in Robotics
The soft and hard bonding boards are integrated to increase the flexible, durable and energy efficiency of soft and soft devices and robots. Stresses are also distributed away from critical joints and components, which minimises wear and tear and increases durability and life. For example, in advanced robotic grippers, a soft-hard bonded structure not only can absorb the impact to protect fragile objects during handling, but also have appropriate adhesion to carry heavy object. It further alleviates one of the most notorious drawbacks of purely soft robots, which is the fatigue failure by creating rigid supports that can limit excessive deformation during cyclical tasks.
Another big advantage is flexibility; these boards assist the robots attain complex motions and function in unstructured environments. For instance, in search-and-rescue robots soft segments are great for squeezing through tight holes but need to be complemented with hard boards to mount sensors and tools. The gains in energy efficiency come from soft materials: the design combines soft elastic materials that store and return elastic energy to reduce the power required for actuation, similar to components in living systems. This is especially useful in autonomous robots where battery life is limited. All in all, improved performance results in robots that are not only more durable and flexible, but also cheaper, in the long run, requiring less maintenance and lasting longer.
Applications and Future Directions
The versatility of innovative soft and hard bonding board solutions in various industries is evident in the impressive 21 different applications, and the impact they have in their respective fields. One application of such boards in the healthcare sector is surgical robots for very delicate instruments that require precise control and a gentle touch so there is no trauma to the tissue being worked on. Hybrid structures provide high comfort and high support which is advantageous for rehabilitation devices, e.g. exoskeletons, allowing for portable and safe rehabilitation that promotes mobility, i.e. active uptake. Soft-hard bonded collaborative robots (cobots) can work and interact together with humans in manufacturing environments and absorb incidental collisions without affecting productivity. Likewise, in other extreme environments where, for example, deep-sea or planetary exploration robots will make the most of these to remain agile while enduring high pressures and temperatures.
As for long term perspectives, future directions are smart materials and adaptable systems with the potential to further distinguish the boundaries of soft and hard components. Current research includes materials with self-healing polymers, variable stiffness and exploration of biomimetic design of materials with tunable properties based on stimuli responsiveness. With AI and ML integration, robotic behavior can then be optimized in hundreds of variables, in real time, through sensory feedback from the bonding interfaces. With the maturation of these technologies even more innovation breakthroughs will provide solutions that stretch the future limits of robots enabling us to work alongside them and tackle global challenges ranging from automation to environmental monitoring.