The design optimization of hydraulic cylinders is a dynamic field where researchers continuously seek to improve performance, efficiency, and durability. Advances in materials, manufacturing processes, and computational techniques have driven significant progress, resulting in more robust and efficient hydraulic systems. One of the primary areas of focus for optimization has been the selection and development of materials [15]. Researchers have explored high-strength alloys, advanced composites, and nanomaterials to enhance the mechanical properties of hydraulic cylinders. For instance, the use of high-strength steel and aluminum alloys has allowed for lighter yet stronger cylinder components, reducing overall weight and improving efficiency. Additionally, composite materials have been employed to achieve higher strength-to-weight ratios, providing superior performance in demanding applications. Advances in manufacturing technologies have played a crucial role in optimizing hydraulic cylinder designs. Precision machining techniques, such as CNC (Computer Numeric Control) machining and additive manufacturing (3D printing), have enabled the production of complex geometries with high accuracy [16]. Additive manufacturing, in particular, has opened up new possibilities for custom designs and rapid prototyping, allowing researchers to experiment with innovative shapes and structures that were previously impractical to produce. This has led to the development of cylinders with optimized fluid flow paths and reduced internal friction, enhancing overall efficiency. The application of computational tools like Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) has revolutionized the design optimization process. CFD simulations help researchers analyze fluid flow within the cylinder, identifying areas of turbulence and optimizing the internal geometry to improve flow characteristics and minimize energy losses [17]. FEA, on the other hand, allows for the detailed analysis of stress, strain, and deformation under various loading conditions. By optimizing the structural design through FEA, researchers can ensure that hydraulic cylinders achieve maximum strength and durability while minimizing material usage. Effective sealing is critical for the performance and reliability of hydraulic cylinders. Advances in sealing technologies have focused on developing materials and designs that minimize leakage and wear. Researchers have introduced advanced elastomers and composite sealing materials that offer superior resistance to high pressures, temperatures, and chemical degradation [18]. Additionally, innovative seal designs, such as multi-lip seals and labyrinth seals, have been developed to enhance sealing efficiency and extend service life [19]. Surface treatments and coatings are essential for reducing friction and wear in hydraulic cylinders. Techniques such as hard anodizing, nitriding, and thermal spraying have been employed to enhance the surface properties of cylinder components. These treatments provide a hard, wear-resistant surface that reduces friction and improves the longevity of the cylinder [20]. Researchers have also explored advanced coating materials, such as diamond-like carbon (DLC) and ceramic coatings, which offer exceptional hardness and low friction coefficients, further optimizing cylinder performance. The integration of smart sensors and control systems into hydraulic cylinders has represented a significant advancement in recent years. These intelligent systems enable the real-time monitoring of operating conditions, such as pressure, temperature, and load. By collecting and analyzing these data, researchers can develop adaptive control algorithms that optimize cylinder performance in real time. This not only improves efficiency, but also enhances safety and reliability by enabling predictive maintenance and the early detection of potential issues. The shift towards environmentally friendly hydraulic fluids is another area of optimization.