Milipol 2025: China's Ribri Technology presents RB21H spherical robot for urban patrol missions.

Beijing Ribri Technology presented the RB21H Spherical Robot at Milipol 2025 as a ground platform built around a high sound pressure level acoustic module for transmitting voice messages in noisy security environments.

At Milipol 2025, the Chinese company Beijing Ribri Technology presents its RB21H Spherical Robot, a compact unmanned ground vehicle (UGV) that combines mobility with powerful acoustic capabilities for security tasks. The company focused on the way the system can project sound and spoken messages in demanding operational environments. The presentation highlighted the robot’s potential role in supporting voice-based communication during security patrols that need clear audio output despite disruptive background noise.
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China's new RB21H suggests that the role of drones in security tasks is shifting from purely auxiliary or reconnaissance use to more routine and integrated patrolling operations, where they work in concert with ground units as real-time, data-driven platforms. (Picture source: Army Recognition)

The RB21H Spherical Robot is described as a spherical robot that integrates a high-performance acoustic module with a high sound pressure level, or SPL. This acoustic module is central to the system’s design, since it allows the robot to transmit sound clearly through noisy environments where conventional loudspeakers might struggle. By concentrating on SPL and clarity, Beijing Ribri Technology positions the RB21H as a specialized platform for situations where spoken words or warning tones must remain understandable even when other sound sources are present. The configuration of the front acoustic section, visible on the dark spherical body, reflects this focus on directed sound output. The combination of spherical form and integrated speaker housing defines the robot’s external appearance. The emphasis on acoustic performance rather than on visual or other sensor payloads differentiates the RB21H within the broader field of small unmanned platforms. All these characteristics were presented as key elements of the system at Milipol 2025.

The peak sound pressure level of the RB21H is given as 142 dB multiplied by two, which indicates that the robot operates with two acoustic sources or channels rated at that peak level. Its continuous SPL is listed as 134 dB multiplied by two, showing that the system is intended not only for short bursts but also for sustained audio output at a very high effective volume. The distinction between peak and continuous values underlines that the robot can handle demanding acoustic tasks over time rather than relying solely on brief, high intensity emissions. Presenting both sets of values allows potential users to understand how the robot behaves in different duty cycles. It also clarifies that the platform is built to maintain reliable performance under continuous operation. These numerical specifications formed an important part of the technical description given for the RB21H during the exhibition.

Beyond its acoustic figures, the RB21H Spherical Robot has a stated speed of 34 km per hour, which places it among relatively fast ground systems in its size category. This speed suggests that once deployed, the platform can reposition between points of interest in a short period of time during patrols or interventions. The system’s weight is given as 180 kilograms, with the corresponding value of 397 pounds, which indicates a substantial structure rather than a light disposable device. This mass implies a robust housing for the acoustic module and drive components, designed to remain stable while the robot moves and broadcasts sound. The weight and speed figures together define how the robot can be integrated into transport and deployment plans, since they indicate the requirements for moving it to and from an operational site. These mobility and mass characteristics complement the acoustic data and give a fuller picture of the platform’s physical nature.

The spherical robot is intended to achieve efficient voice warnings in areas where security personnel must address individuals or groups from a distance. By projecting spoken messages at high SPL levels, the system can be used to convey warnings, instructions, or alerts while remaining separate from the source of potential danger or disturbance. The text also states that the RB21H supports remote communication in security patrols, which indicates that it can act as an intermediary audio node between operators and people within the patrol area. This role is particularly relevant in environments where direct human presence is limited by safety, access, or resource constraints. Clear transmission of voice messages is therefore not presented as an optional feature but as one of the central functions of the robot.

Many security operations take place in areas where engines, crowds, alarms, or other devices create a persistent acoustic background that can mask important messages. By specifying that the robot transmits sound clearly through noisy environments, Beijing Ribri Technology indicates that the acoustic module and SPL values are chosen to overcome this challenge. The integration of a high-performance acoustic module with high SPL is therefore directly linked to the robot’s mission profile. Rather than describing a multi-purpose platform with many interchangeable payloads, the information centers on the ability to ensure that voice outputs remain intelligible when interference is present. This focus differentiates the RB21H from general-purpose robots that may only offer basic loudspeaker functions. It also anchors the platform firmly in the category of security support systems designed around communication.

During the Milipol 2025 presentation, Beijing Ribri Technology framed the RB21H Spherical Robot as a specialized tool for security patrols that require reliable voice projection and remote communication. The company’s choice to present detailed acoustic and mobility figures allowed potential users and partners to evaluate how the robot might fit into their existing patrol concepts and equipment inventories. By combining a spherical form factor with a high SPL acoustic module, a top speed of 34 km per hour, and a weight of 180 kilograms or 397 pounds, the RB21H is positioned as a single integrated platform rather than a modular kit. The emphasis on efficient voice warnings and remote communication in security patrols summarized the intended use case. In this way, the Milipol 2025 appearance provided a concise yet complete view of how Beijing Ribri Technology envisions the RB21H contributing to security operations that depend on clear, persistent audio communication.

Drones are increasingly used for security patrol tasks as their ability to launch rapidly, cover wide areas, and provide real-time visual and thermal monitoring allows teams to detect movement, perimeter breaches, or unusual activity more efficiently than with ground patrols alone. They can reach an incident site within minutes and observe locations from low altitude angles that fixed cameras or vehicles cannot access, which improves awareness during both routine patrols and fast-moving events. Drones equipped with high-definition cameras, thermal imaging, loudspeakers, or automated detection functions can relay continuous information to operators who adjust patrol routes or respond to incidents based on what the drone observes. Their use also reduces exposure risks for personnel during hazardous situations by allowing initial assessment, mostly from the air, before ground units approach.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.