## 2 Related Studies
### Locomotion  
In robot locomotion, wheeled locomotion is commonly used over other methods due to its simplicity, speed, and efficiency on flat surfaces, offering lower energy consumption, reduced complexity, and cost-effectiveness. In wheeled locomotion, types like ball [17], two-wheel [18], three-wheel [19], and multi-wheel [20], each with drive mechanisms like differential drive, Ackermann steering [21], and omnidirectional, serve different applications as illustrated in Figure 5. [PERSON] et al. [18] investigated the constraints of maintaining stability for a two-wheel robot. The two-wheeled robot was most suitable for flat terrains. [PERSON] et al. [19] developed a three-wheeled holonomic motion system with autonomous navigation capabilities for navigating complex, even indoor terrain. Ackermann steering is a standard method of locomotion for wheeled vehicles. It enables the front wheels to steer at different angles during turns, making it suitable for indoor and outdoor paved surfaces [21]. Differential drive is mainly used for robotic applications, where the two/four wheels must be controlled independently, allowing the vehicle to move in different directions by varying the speed of each wheel. [PERSON] et al. [20] developed an omnidirectional floor-cleaning wheeled robot equipped with four omnidirectional wheels for narrow and crowded spaces. [PERSON] et al. [22] designed a four-wheel independently driven skid-steered mobile robot designed for industrial automation and outdoor exploration. It addresses the chattering phenomenon in skid-steered robots by proposing a coordinated adaptive robust control, ensuring smooth operation and improved control performance under varying ground conditions. The synchro-drive principle relies heavily on gear mechanisms, where one motor controls the rotation around the horizontal axis, generating traction, and another controls the rotation around the vertical axis for direction [23]. Articulated pivot steering connects the front and rear of heavy machinery via a central pivot joint, allowing independent movement that reduces the turning radius and enhances maneuverability in confined areas [24]. Tracked locomotion offers improved traction, stability, and navigation on rough terrain, making it well-suited for heavy-duty applications. As shown in Figure 6, tracked robots include types like continuous track, flexible belt, triangular track, flipper track, rigid metal track, articulated, dual, and hybrid, each tailored for specific terrains. Continuous track robots, also known as caterpillar track robots, use a single band of treads and excel in rough or soft terrain, offering superior traction and stability compared to wheels [25]. A dual-track robot uses two tracks for stability and traction on rough terrain. It is ideal for rugged landscapes, construction sites, and military operations, where mobility and load-bearing are essential [26]. An articulated track robot features a flexible design with two segments connected by a pivot, allowing for improved maneuverability in tight spaces. It is ideal for narrow or cluttered environments like disaster response, search and rescue, and agricultural applications [27]. A triangular track robot utilizes a three-pointed system for traction and stability on rough terrain, making it ideal for steep or uneven surfaces, such as mountains, construction sites, and exploration areas. A staircase-climbing robot navigates stairs and vertical obstacles, making it useful in indoor environments [28]. [PERSON] et al. [29] developed TALBOT, a tracked-leg transformable robot designed for all-terrain adaptation [30]. Flexible belt track offers mobility on soft or uneven terrain, which is suitable for agricultural fields, forests, and muddy or sandy areas needing smooth movement [31]. Flipper tracks have flipping mechanisms for overcoming obstacles in highly uneven terrain,  
Figure 5: Example of Wheel Drive-type locomotion. (**a**) Ball robot, inspired from [17]. (**b**) Two-wheeled, Differential Drive, inspired from [18].