Surgical robotics company Medrobotics is on its way to a $20 million funding round, having raised $8.1 million so far.

The Raynham, Mass.-based medical device company, originally known as Cardiorobotics, is working on a multi-link robot for minimally invasive surgical procedures, hoping to "replace open surgical procedures for many parts of the anatomy that are otherwise difficult or previously impossible to reach," the company’s website says.

Medrobotics describes its platform as "a new generation of flexible robotic snakes with advanced vision systems that are able to navigate tortuous paths."

The robotics maker opened its latest round of funding late last month, and has sold debts and other rights to 18 unnamed investors thus far, according to SEC filings.

Medrobotics has another funding round pending, in which the company has raised $6.5 million of a hoped-for $10 million among 14 investors through sales of debt and other rights to acquired securities. A 3rd open round has raised $3.6 million of $6 million among 15 investors.

Medrobotics plans to file for U.S. commercial approval for its surgical snake this year.