Lewis Hamilton says he is confident he has resolved the problems which blighted him for much of last season.

The McLaren driver admitted 2011 was his worst in F1, but believes a winter away has led to a more positive mindset as he approaches the 2012 campaign.

“I feel very fresh,” the 27-year-old former world champion said at the launch of McLaren’s new car.

“Whichever issues I had I’ve worked hard to clarify and make sure I come into this year without any worries.”

He added: “I feel very clear in my mind so I feel I can arrive on the right foot.”

Hamilton spent the winter training in the Rocky Mountains in Colorado, USA.

“It feels fantastic to be back,” he said. “I have been training an incredible amount over the winter but just in the right way – I gave myself plenty of time to recover and recuperate.”

He had an up-and-down time in 2011, with three wins interspersed with numerous on-track collisions and some off-track controversies.

Asked what he had learned from his travails, he said: “I think I’ve just matured. I’m 27 now. It’s the way you behave, the way you handle yourself, ways you interact with the team.

“There are definitely things I can pay more attention to and work harder on. Most important is focus, to be world champion again.

“The car looks great. I saw it for the first time three days ago. I think it looks beautiful. Last year’s car looked a bit different – this one looks like a real car.

“It’s very clean at the back, and that’s not fake. That’s how the car is. I hope it drives as well as it looks.”

The McLaren will run for the first time with test driver Oliver Turvey at the wheel in a brief aerodynamic test in Spain at the weekend, before Hamilton’s team-mate Jenson Button takes over for the first two days of the first official pre-season test at Jerez from Tuesday.

Button was bullish about the team’s prospects of taking the fight this year to Red Bull and Sebastian Vettel, who dominated last season on their way to winning the drivers’ and constructors’ titles for the second consecutive year.

“I feel there’s not an area we haven’t really worked on, so we have no excuses,” Button said.

“F1 is a very competitive business at the moment in terms of the drivers – six world champions – but also the teams.

“Red Bull, Ferrari, ourselves, Mercedes will be strong. But for us, we go out there to win the championship and that has to be our aim from the get-go.”