Public prosecutor Leif Johansson mulled pressing charges against the firm but eventually opted to settle for a fine.
"I've never heard of a robot attacking somebody like this," he told news agency TT.
The incident took place in June 2007 at a factory in Bålsta, north of Stockholm, when the industrial worker was trying to carry out maintenance on a defective machine generally used to lift heavy rocks. Thinking he had cut off the power supply, the man approached the robot with no sense of trepidation.
But the robot suddenly came to life and grabbed a tight hold of the victim's head. The man succeeded in defending himself but not before suffering serious injuries.
"The man was very lucky. He broke four ribs and came close to losing his life," said Leif Johansson.
The matter was subject to an investigation by both the Swedish Work Environment Authority (Arbetsmiljöverket) and the police.
Prosecutor Johansson chastised the company for its inadequate safety procedures but he also placed part of the blame on the injured worker.