The wheel is designed with obstacles in the ball's path to randomize its movement.
这个轮盘在小球的行进路线上设计了令其能够随机停下的障碍。
《柯林斯英汉双解大词典》
2
These actions include things like depressing a key (NoteOn), releasing a key (NoteOff), changing a synthesizer program or patch setting and movement of a pitch wheel to alter a note's pitch.