Chinese researchers have developed the BHMbot-B, a highly agile 15 mm-long microrobot capable of quick forward and backward movements, making it ideal for navigating tight and confined spaces. This innovative design combines a variety of advanced technologies to offer unprecedented mobility and adaptability, enabling it to perform tasks in environments where larger machines would struggle.
The BHMbot-B achieves its remarkable versatility through a unique control mechanism. The robot’s forward and backward motion is made possible by aligning the vibratory movements of its magnet, cantilever, and linkages using a process known as vibration mode transition control. This allows the robot to switch between motion modes with precision, enabling it to maneuver through challenging environments efficiently.
The research team from Beihang University explains that the BHMbot-B integrates several key components: a battery, a wireless control circuit, and two electromagnetic actuators that provide significant load-bearing capacity. The robot demonstrates impressive speeds, achieving 18.0 body lengths per second (360 mm/s) while moving forward and 16.9 body lengths per second (338 mm/s) while moving backward. This makes the BHMbot-B a nimble and precise tool for tasks that require quick movement in confined spaces.
Large machines often face difficulties navigating confined spaces during tasks like inspections or unclogging, where the risk of structural damage is high. Microrobots have emerged as a solution, offering rapid movement and precise turning. However, these small robots face significant challenges in narrow tunnels or dead ends, where they may become trapped and unable to continue their movement.
Unlike insects, which instinctively retreat when they encounter obstacles, most microrobots lack the ability to move backward effectively—a critical skill for navigating unknown, confined environments. Previous microrobot designs, like the HAMR robot, used multiple actuators to enable forward and backward movement, but such systems are complex and difficult to miniaturize for untethered use.
In contrast, the BHMbot-B introduces a simpler and more efficient solution, using frequency-controlled vibration to enable both forward and backward movement. This innovation allows the robot to switch between different vibrational modes, giving it the flexibility to navigate obstacles and reverse direction without turning.
The BHMbot-B operates using a combination of an electromagnetic actuator, cantilever, and a four-bar linkage system. The cantilever moves when alternating current is applied to a coil, causing the attached magnet to oscillate. The robot’s forelegs move in response to these oscillations, allowing it to swing forward or backward depending on the vibration mode.
In the first-order vibration mode, when the cantilever and magnet move in the same direction, a forward friction force is created as the forelegs strike the ground, propelling the robot forward. In the second-order vibration mode, the cantilever and magnet move in opposite directions, causing the forelegs to exceed their equilibrium position and generate backward friction, allowing the robot to reverse its direction.
According to the team, high-speed camera analysis reveals distinct gaits for both forward and backward movements, ensuring precise control and kinematics. This capability allows the BHMbot-B to recover from dead ends in confined spaces and continue its navigation without external assistance.
The robot achieves remarkable speeds, reaching 38.7 body lengths per second (163 Hz) while moving forward and 44 body lengths per second (680 Hz) while moving backward. Interestingly, its backward speed is higher than its forward speed, due to more efficient foreleg-ground contact during backward movement.
One of the standout features of the BHMbot-B is its impressive load-bearing capacity. Equipped with tiny rollers on its hind legs, the robot minimizes friction and enhances its ability to carry heavier loads. The BHMbot-B can transport objects up to 32 times its own weight, such as a 5.18-g metal column, while maintaining a speed of 3.2 body lengths per second. It can also support more than five times its own body weight, making it a highly efficient carrier for tasks in tight spaces.
The BHMbot-B has been designed for versatility across various surfaces, including glass, sand, and curved tubes. It is capable of moving forward and backward untethered, carrying essential equipment like a battery, gyroscope, or micro-camera. This makes it ideal for real-time data transmission and imaging in confined environments where human access is difficult or impossible.
Looking to the future, the research team plans to enhance the BHMbot-B with additional capabilities, such as environmental sensing and autonomous navigation. These upgrades will improve its performance in complex and unpredictable environments, expanding its potential applications in fields such as medical diagnostics, industrial inspections, and environmental monitoring.
In conclusion, the BHMbot-B represents a significant advancement in microrobot technology, offering exceptional agility, high-speed movement, and an impressive load-bearing capacity in confined spaces. With its unique ability to move both forward and backward using vibration mode transitions, it holds great promise for a wide range of applications in challenging environments.
By Impact Lab
