## 2 Design Methodologies
The steps of the AHP method in this work are:Step 1. Define the decision problem: Clearly state the objective of selecting the best conceptual design based on the specifications and requirements from previous phases. Step 2. Establish the hierarchy: Create a hierarchical structure that represents the criteria and alternatives. The top level could be the objective of selecting the best conceptual design, followed by intermediate levels representing criteria such as functionality, aesthetics, feasibility, and other relevant factors. The bottom level would include the alternative conceptual designs. Step 3. Pairwise comparisons: Compare each criterion with every other criterion and assign numerical values to represent their relative importance or preference. For example, compare functionality with aesthetics and assign a value based on their relative importance. Step 4. Create a comparison matrix: Construct a square matrix for each level of the hierarchy, where the elements of the matrix represent the pairwise comparisons made in the previous step. Step 5. Calculate priorities: Calculate the priority vector for each matrix by normalizing the columns of the matrix and computing the average values. Step 6. Check for consistency: Assess the consistency of the judgments by calculating the consistency ratio (CR). If the CR exceeds a predefined threshold (e.g., 0.1), you may need to revise the pairwise comparisons to ensure consistency. Step 7. Aggregate priorities: Multiply the priority vectors of each level to obtain the weighted priorities for the alternative conceptual designs. Step 8. Perform sensitivity analysis: Conduct sensitivity analysis to evaluate the stability of the results and assess the impact of changes in the pairwise comparisons. Step 9. Make the decision: Use the weighted priorities to rank the alternative conceptual designs and select the one that best fits the specifications and requirements. 5. Detailed Design. Once the solution for the need has been chosen, it is necessary to determine the components and interactions. Shapes are defined with greater rigour, taking into account geometries, interactions, etc. These factors condition the dimensions of the product and have to be taken into account when making overall drawings with general dimensions. In this paper, the sections corresponding to the detection of the need, market study, and technical design specifications have been omitted, and it focuses on the Conceptual Design and Detailed Design of the Product. In addition, it is necessary to research all types of existing mechanical systems for their possible study and comparison. In this way, a sweep is made of all existing ones, observing and understanding different types of mechanisms similar to the one to be designed by means of audiovisual and written documentation, covering as many fields of study as possible. Once the sketches have been generated from the mechanical systems studied, they are evaluated, and the best ones are selected using AHP techniques. Likewise, in order to know the scope and quality of the selected product (sketch) to be designed in detail, quality assessment techniques are used. In this case, the quality assessment technique has been the QFD method.