In the world of Frank Herbert's 1965 novel Dune, members of royalty must be able to defend themselves using swords and knives. A special fencing robot and mirror system are used by a trainer to help royal family members, like Paul Atreides, to prepare:

He [Swordmaster Gurney Halleck] gestured to the practice dummy. "Now, we'll work on your timing. Let me see you catch that thing sinister. I'll control it from over here where I can have a full view of the action. And I warn you I'll be trying new counters today."
(Read more about the fencing robot and mirror)

Here is another, more descriptive quote from Dune Messiah:

As she moved into the training room, Alia caught her own reflection multiplied thousands of times in the crystal prisms of a fencing mirror swinging in the heart of a target dummy. She saw the long sword waiting on its brackets against the target, and she thought: Yes! I'll work myself to exhaustion -- drain the flesh and clear the mind.
The sword felt right in her hand. She slipped the crysknife from its sheath at her neck, held it sinister, tapped the activating stud with the sword tip. Resistance came alive as the aura of the target shield built up, pushing her weapon slowly and firmly away.
Prisms glittered. The target slipped to her left.
Alia followed with the tip of the long blade, thinking as she often did that the thing could almost be alive. But it was only servomotors and complex reflector circuits designed to lure the eyes away from danger, to confuse and teach. It was an instrument geared to react as she reacted, an anti-self which moved as she moved, balancing light on its prisms, shifting its target, offering its counter-blade.
Many blades appeared to lunge at her from the prisms, but only one was real. She countered the real one, slipped the sword past shield resistance to tap the target. A marker light came alive: red and glistening among the prisms . . . more distraction.
Again the thing attacked, moving at one-marker speed now, just a bit faster than it had at the beginning.
She parried and, against all caution, moved into the danger zone, scored with the crysknife.
Two lights glowed from the prisms.
Again, the thing increased speed, moving out on its rollers, drawn like a magnet to the motions of her body and the tip of her sword.
Attack -- parry -- counter.
Attack -- parry -- counter . . .
She had four lights alive in there now, and the thing was becoming more dangerous, moving faster with each light, offering more areas of confusion.
Five lights.
Sweat glistened on her naked skin. She existed now in a universe whose dimensions were outlined by the threatening blade, the target, bare feet against the practice floor, senses / nerves / muscles -- motion against motion.
Attack -- parry -- counter.
Six lights . . . seven . . .
Eight!
She had never before risked eight.
In a recess of her mind there grew a sense of urgency, a crying out against such wildness as this. The instrument of prisms and target could not think, feel caution or remorse. And it carried a real blade. To go against less defeated the purpose of such training. That attacking blade could maim and it could kill. But the finest swordsmen in the Imperium never went against more than seven lights...