As far as I know, there is no historical connection between the "internal" Chinese arts of hsing-i, taijiquan, and pagua(spelling?), and aikido. I believe they have been described as having similar traits such as stressing the cultivation and use of chi/ki, the lack of the use of "brute force," and extreme precision of movements in their techniques.
I trained in Chen style taijiquan for twelve years prior to starting aikido. The only reason I don't continue to do both is lack of time (new family) and lack of a Chen style taijiquan instructor near me. I very much enjoyed the short period that I did practice the two arts concurrently. They were different enough that they didn't interfere with each other, but still shared many similarities as well (I know, a very ambivalent statement). That said, if one desires to study both arts, I would suggest accruing some significant training time in one of the arts prior to beginning the other, in order to avoid confusing the movements and techniques of the arts. IMHO.