# Swarm Robotics: A Perspective on the Latest Reviewed Concepts and Applications
## 4 Swarm Robotic Projects
### Robotic Platforms
Its objectives include cost reduction and simplifying the platform programming, and tool-chain [59]. * _microUSV_ is a small platform to validate marine swarm robotics appliances. It features 3D-printed parts and off-the-shelf components to compose its design [60]. * _mROBerTO_ and _mROBerTO 2.0_ are robotic platforms with advanced computational and sensing abilities to create swarm robotics applications. The advances on this platform allowed the creation of platforms with more reliability and repeatable locomotion [61]. * _Kilobot_ is a very small and scalable robotic platform designed to test collective algorithms with hundreds or thousands of robots. This platform has a very low cost and is easy to assemble and operate [62; 63]. * _Tribots_ are three-legged robots designed to reproduce complex strategies from ants, including the evasion from large predators. The robots are insect-scaled and easy to assemble. Nonetheless, it allows a set of five different movements [64]. To better understand and compare these various solutions, we provide a taxonomic analysis of the solutions. The chosen criteria were hardware and physical features. We extracted the most valuable information from the hardware used to prototype and build the solutions from the papers. We chose to analyze the primary CPU/MCU, Memory, Extra MCU units, Sensors, Actuators, and Robot size. We notice that most solutions use low-power PIC or ATmega MCUs, or even ARM CPUs to perform the operations from the presented data. Clock frequencies vary from 4 MHz to 1 GHz. Most systems have Lithium batteries, providing from 3.4 to 11.1V. The sensors, actuators, and sizes vary according to the purpose of the robot. Finally, some solutions apply extra MCU units to handle low-level tasks. Table 1 provide the data from this analysis. Finally, we gathered the main features of swarm robotic solutions. Based on the evaluated information, swarm robotic solutions should present these main features:  
* _A primary CPU/MCU_, responsible for the high-level robot intelligence. As stated before, swarm robotics usually have low-level intelligent tasks, as the intelligence is usually collective. Thus, usually, the platforms have low-power MCUs or embedded CPUs with constrained resources. 2. Some solutions present _auxiliary MCU modules_. These modules are usually responsible for real-time tasks. There is no guarantee of real-time operations in more elaborated solutions, especially those using CPUs with embedded OSs. Thus, these auxiliary units control these low-level tasks. 3. The robot context-awareness comes from the _Sensors/Transducers_. These devices include the communication modules, as collective intelligence is a critical feature in swarm robotics. 4. The interaction with the environment and neighbors comes from the _Actuators/Transducers_. Again, the communication modules are also a part of this feature, as they have active participation in the communication and collective intelligence. For instance, many robots use IR LEDs and phototransistors to perform local communication. 5. Sizes vary from microrobots of 1.6 cm (approximately 1 inch) to 23 cm. Nonetheless, all solutions can be considered _low-size robots_, as this feature is essential for the swarm's scalability.