# Design and Analysis of a Planar Six-Bar Crank-Driven Leg Mechanism for Walking Robots
## 9 Conclusions  
This paper presents the design, kinematic analysis, and optimization of a six-bar crank-driven leg mechanism integrated with an embedded skew pantograph for walking robots. The kinematic analysis using GIM software and MATLAB validated the mechanism's ability to generate a high-lift foot trajectory with sufficient ground clearance, ensuring stable and efficient walking across uneven terrains. The mechanism's compact design provides an optimal balance between simplicity, performance, and cost-effectiveness, making it suitable for practical applications where mobility over rough or obstructed surfaces is essential, such as in agriculture, search and rescue, and planetary exploration.  
The use of topology optimization significantly reduces the weight of the ground-contacting link without compromising its structural integrity. Additionally, the stress analysis confirms that the design can withstand expected operational loads, demonstrating its readiness for real-world implementation.  
The mechanism is compared with [PERSON]'s and eight-link mechanisms, with differences noted. Advantages of the proposed leg mechanism include the following:  
1. The mechanism is mounted on a frame with only two fixed pivots while preserving its structural stability.
2. The proposed mechanism can be constructed using binary links, although ternary links can also be used.
3. The walking mechanism can be built compactly, resulting in less weight and inertia, making it suitable for speed walking.
4. The mechanism performs well during both clockwise and counterclockwise rotation of the crank.
5. This mechanism has a compact stride-to-size ratio and high lift.  
The practical applications of this mechanism could include autonomous agricultural robots capable of navigating through complex and uneven farming environments, robots used for planetary exploration where the terrain is unpredictable, or robots designed for urban search and rescue missions that require adaptability to various surfaces.  
Future research could focus on improving the energy efficiency of the mechanism by exploring alternative materials or lightweight composites that maintain their structural integrity while reducing their mass further. Additionally, exploring control systems that  
Figure 14: CAD design of the proposed walking robot.  
can adapt the walking gait based on sensor feedback from the environment would enhance a robot's ability to operate autonomously in more dynamic conditions. Prototype development and real-world testing would be the next step in validating this design in various environmental scenarios.  
Conceptualization, E.G.-H., S.A. and A.S.; software, E.G.-H., S.A. and B.P.; validation, O.M. and S.A.; formal analysis, E.G.-H.; writing--original draft preparation, E.G.-H., A.S., B.P., O.M. and S.A.; writing--review and editing, E.G.-H., S.A. and O.M.; visualization, S.A., B.P. and E.G.-H.; supervision, E.G.-H.; project administration, E.G.-H., O.M. and S.A. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Data Availability Statement: Data is contained within the article.  
The authors wish to acknowledge [PERSON], CompMech, Department of Mechanical Engineering, UPVEHU, for granting them permission to use GIM software. (www. ehu.es/compmech) (accessed on 21 January 2024).  
The authors declare no conflicts of interest.