The Green Machines of Marine Robotics

As the costs of electronic components have continued to drop over time, there has been a noticeable trend towards disposable electronics, where electronic devices are designed and manufactured with a limited lifespan in mind. Whether it is a single-use medical diagnostic device, or a smartphone that is intended to become obsolete in two years, these gadgets are everywhere these days. As is the case with most technologies, there are a number of pros and cons to consider that arise as a result of this trend.

One of the primary benefits of disposable electronics is affordability and accessibility. Lower-priced disposable devices allow individuals with limited budgets to enjoy the benefits of electronic technology, such as smartphones, tablets, and other gadgets.

Disposable electronics also cater to the needs of those who desire frequent upgrades or have specific requirements for specialized devices. The market demand for the latest features and functionalities drives innovation, pushing manufacturers to introduce new models regularly. This constant influx of new and improved products provides consumers with a variety of options to choose from, empowering them to select devices that best suit their needs and preferences.

However, this trend may also lead to severe negative environmental impacts. One of the significant concerns is the accumulation of e-waste. With shorter lifespans, discarded devices contribute to the ever-growing problem of e-waste. Improper disposal of electronic waste poses environmental and health risks, as it often contains hazardous substances like lead, mercury, and cadmium. Furthermore, the extraction of raw materials needed for manufacturing disposable electronics contributes to habitat destruction, pollution, and resource depletion.

So, can we have our cake and eat it too? Based on the recent work done by a group of researchers at Carnegie Mellon University — maybe. This team has developed seaweed-based, biodegradable actuators that are ideal for use in robots that are intended to be disposable, or that may otherwise be lost in the wild in the course of their normal duties. This innovation is limited to certain types of actuators, so it will not solve all of our problems with e-waste, but it is an environmentally-friendly step in the right direction.

The method involves the creation of a bio-ink made of calcium-alginate that is sourced from the common brown seaweeds Lessonia nigrescens and Lessonia trabeculata. These inks are used with a previously developed FRESH 3D bioprinting technique, which allows for the printing of soft gels. By carefully controlling the ionic crosslinking process and print pathing, the researchers were able to create water-tight structures that have utility in a number of soft grasping tasks. It was also shown that by varying the degree of crosslinking, the shape and stiffness of the actuators could be altered to suit different purposes.

Ideal for marine applications, these soft actuators that can extend, bend, and twist to interact with delicate plants and animals, or whatever else the mission may call for. And when the mission is complete, the actuators will safely degrade in about a week, and are even safe for marine animals to eat.

Despite the early successes, there is still some work to be done. The team has only just begun to explore the range of hyperparameters of the FRESH printing process, so there may be additional areas for optimization. Furthermore, the actuators have only been tested for hundreds to tens of thousands of cycles thus far — well short of the millions of cycles traditional actuators are tested for to assess fatigue and wear. Moreover, all of the experiments have been conducted under controlled conditions. Future work will need to verify utility under real-world conditions.

After working through issues such as these, the researchers plan to continue advancing their work, with the goal of building entire robotic systems from environmentally-friendly biodegradable materials.