I want to imitate a machine with the same principle of action, structure and use. Is it infringement?

First, it depends on whether the machine has intellectual property protection (such as patent rights) (authorization, not just submitting applications). If not, of course, there is no infringement.

Second, if this machine is protected by intellectual property rights, it depends on whether your counterfeit product is within the protection scope of the other party's patent documents (not compared with the other party's products). If not, there is no infringement.