A hearing was scheduled for Monday morning in a downtown Los Angeles courtroom, with Richards asking for a restraining order to be made permanent against Phypers.
Richards and Phypers were seen entering the courthouse separately, accompanied by their respective attorneys. Sheen was not seen as of 11 a.m., and it was unclear if he would testify Monday or perhaps later in the week at the request of Phypers.
Richards alleges numerous acts of domestic abuse in the case, including Phypers allegedly slamming her head into a towel rack, giving her a black eye, and hacking into her laptop and phone.
Richards attorneys have claimed that she found a box of Phypers' firearms and a photo of her nude with another man, which Phypers allegedly threatened to release.
Meanwhile, Phypers has accused Richards of having an extramarital affair.
Richards was married to Sheen from 2002 to 2006.
Sheen's tumultuous journey toward sobriety is unabashedly laid out in Sheen's tell-all memoir, "The Book of Sheen," which was released last month. It describes in detail what led to Sheen's three marriages and divorces.
Charlie Sheen admits he was a sex addict, says he was extorted by partners
He embarked on a whirlwind romance with Donna Peele, his first wife, which quickly turned sour soon after their marriage in 1995. He made a drunken spectacle at the wedding, got drunk during the flight home from the honeymoon - during which the pilot let him fly the plane for about 90 seconds - and threw their wedding rings out of a sunroof during an explosive fight. "I blame myself for most of our dustups, with booze being the easiest culprit to pin it on," he wrote. "Our situation needed a villain to blame."
Sheen met his second wife, Richards, on a film set in the early 2000s and reconnected shortly after, when she guest starred on "Spin City." The pair dated for about two months before he proposed, which he said was spurred by the Sept. 11, 2001, attacks and his three-and-a-half year sobriety.
"For the first time in years," he wrote, "my feelings were accessible and based in reality." Right around the time Sheen was cast on "Two and a Half Men," Richards had given birth to their daughter, Sam, and their home life was crumbling. Sheen turned to prescription pills and the two divorced shortly after their second daughter was born.
The Associated Press contributed to this report.