Size Matters

Small robots, often referred to as microbots, are growing in importance as tools in a variety of fields, with notable applications in equipment inspections and search and rescue operations. These diminutive machines are designed to navigate confined spaces and access hard-to-reach areas, offering a level of versatility that larger robots or humans may struggle to achieve. Their compact size allows them to explore environments that are hazardous or inaccessible, providing crucial information and assistance in many situations.

However, the development of small robots is not without its challenges. The size constraints impose heavy limitations on the capabilities that can be incorporated into them. As designers strive to enhance a robot's functionality by adding more actuators, sensors, and battery power, they are confronted with a delicate balancing act. The challenge lies in maintaining a compact size while accommodating the necessary components for improved performance. The addition of capabilities often comes at the cost of increased size and weight, potentially compromising the robot's ability to navigate through tight spaces and hindering its overall effectiveness.

It is these trade-offs that make Carnegie Mellon University’s robot, named Mugatu, so special. The developers of Mugatu found a way to do more with less, enabling this bipedal robot to walk and steer itself using only a single actuator. This has the effect of minimizing the overall size of the required hardware. There are no strings attached either, Mugatu is fully self-contained. As such, future designs that employ similar principles could prove to be useful in real-world applications — not just under controlled laboratory conditions.

The body of the robot is composed of two separate rigid pieces. Through careful placement and control of the actuation system, these pieces can be made to produce a walking motion. Modifications to the timing of these motions can be utilized to cause Mugatu to steer to either the left or the right.

At present, Mugatu is not actually all that small, as far as microbots are concerned. However, the team notes that the most important part of their work was simplifying the walking motion. With that understanding, the design can be scaled down (or up) as needed to accommodate the task at hand, like fitting into a pipeline for inspections, for example.

There is still much work to be done before we see robots based on Mugatu in the wild, however. Aside from shrinking the size of the robot down, a more advanced control system needs to be implemented. Presently, Mugatu will simply carry out a set of pre-programmed tasks on powering up. Moreover, to be useful in the real world, sensing systems will also need to be incorporated into the small form factor. But in any case, the work done by this team in showing how much can be accomplished with a single degree of freedom should inspire other designers of robotics systems to advance their own creations.