First Lady Michelle Obama (R) and her daughters Malia (C) and Sasha cheer as Beyonce returns to her seat after singing the Star Spangled Banner after the swearing-in of US President Barack Obama in Washington, Jan 21, 2013. [Photo/Agencies]

US first lady Michelle Obama is expected to steer clear of controversial issues when she visits China this week but her trip could help advance a top item on her husband's foreign policy agenda: deepening Washington's ties with Beijing.

The week-long trip marks only the third foreign solo trip for Obama, who has cultivated a self-described "mom in chief" image, putting her energy into raising her daughters Malia, 15, and Sasha, 12, and signature domestic policy issues such as combating childhood obesity.

She has joked that her motto during her husband's White House tenure has been to "do no harm."

In keeping with that cautious approach, the White House said Obama's message on the trip will focus on cultural ties between the two countries and "the power and importance of education" for young people in both countries.

But her trip, which will be front-page news in China and closely parsed by media, will carry important symbolic value.

"There's no better surrogate for a president overseas than their spouse," said Anita McBride, who was chief of staff to former first lady Laura Bush.

McBride said Obama's visit with Chinese first lady Peng Liyuan can send a powerful diplomatic message, even if what they discuss has little to do with pressing bilateral issues.

"Those are images that convey a relationship," she said.

Obama will also visit with students and schools, and take her daughters to see the famous Terracotta Warriors.

Since taking office in 2009, President Barack Obama has put a high priority on bolstering the US relationship with China. That goal could take on even greater significance given the deep rift has opened up between the United States and Russia over the Ukraine crisis.

"She has chosen a more traditional, non-confrontational role as a first lady," said Laura van Assendelft, a political scientist at Mary Baldwin College. "Other first ladies have pushed those boundaries. Michelle Obama is not pushing any boundaries."

As first lady, Obama traveled to Mexico in 2010 and to Africa the following year. A private trip to Spain in 2010 with daughter Sasha backfired when she was criticized for spending taxpayer funds on security for what amounted to a holiday.

Now that her husband is in his second term, and does not have to worry about being reelected again, Michelle Obama may take more foreign trips to advance policy goals, McBride said.

"You begin thinking about what you want to leave behind," said McBride, now at American University in Washington.  

Three generations

Obama will deliver another strong, if unspoken, message by taking her daughters and her mother, Marian Robinson, with her to China, said Robert Daly, director of the Wilson Center's Kissinger Institute on China and the United States.

Robinson lives with the Obama family in the White House.

"The Chinese are very big on three generations under one roof. That is one of the cornerstones of their culture," Daly said. "That will play very well in the Chinese media."

Pictures of the three generations of four strong women will make a statement about women's equality and opportunity, he added.

Obama's visit comes before her husband visits Asian allies Japan, South Korea, Malaysia and the Philippines in late April.

Ahead of the president's trip, the White House will want "sweetness and light" from Michelle Obama's China visit, said Dan Blumenthal, an adviser on China issues in the former George W. Bush administration.

"She can just be who she is, and it's a win. She doesn't have to carry a tough message," said Blumenthal, now director of Asian studies at the American Enterprise Institute think tank.