When it comes to trying to make it in the booming, competitive US AI and digital tech market, Kiwi entrepreneur Harry Mellsop has some advice for young aspiring New Zealand founders: don't be afraid of being out of your comfort zone."I think, for me, the thing that's always worked well is just trying to put myself in the biggest, scariest, most intimidating room that I could find. And you know you jump in at the deep end and you have to figure out how to swim, but it's the way to kind of grow the fastest."It is a strategy that has clearly worked for Wellington-born 28-year-old Mellsop, who moved to the US from New Zealand after finishing school.He is now co-founder of AI testing simulator Antioch, which has just raised $54 million from backers, including Silicon Valley's Greylock and Icehouse Ventures.The move into AI tech start ups for Mellsop came working at Kiwi investment incubator firm Icehouse Ventures in the US, study at Stanford University and a stint at the auto-pilot team at Tesla.Staff working in Antioch's office.Supplied / AntiochAntioch is a New York-based tech firm that creates digital simulation testing platforms, allowing companies to road-test AI robots before they are used in real life."You don't want the first time that you switch a system on to be in the real world where it's operating a 20-ton excavator or something like that, right? That's where things become genuinely dangerous."And so what we do is we allow companies that are building these systems to switch them on inside these digital worlds, basically, observe how they perform, get really, really confident that this is going to be safe for the real world. And only then do you actually put it on the real vehicle, the real robot, the real drone."Some of the companies it has announced it is working with include Amazon-owned home security company Amazon Ring.Antioch, which has 12 staff in New York and two staff in New Zealand, has been backed by Silicon Valley investor Greylock and local incubator Icehouse Ventures.The company also has partnerships with tech giant Nvidia and cloud company Nebius.Mellsop said Antioch's goal was to try to solve some of the problems large manufacturers faced with new technologies such as robots."So maybe some of the big automakers, for example, if you're trying to cut 10, 20 percent out of your manufacturing costs to be competitive with some of these newer players out of China, for example, you need to be looking at automation. And so they approach us, they approach Nvidia, and we work together on some of those relationships there."He said the extra money raised would allow the company to expand its footprint in the US with an office in San Francisco and enhance its technology."So, I think in terms of what this capital is going to allow us to do, it's going to allow us to bring our work to a wider set of customers."