Verbs of perception and emotion frequently occur in the SC (suffix conjugation) to express an event that began in the past and lasts to the present. They are frequently translated in English as present tense. For instance, "I know" does not mean in biblical Hebrew "I am exercising the act of knowing as I speak."; it means "I have acquired knowledge of something." That's what ידעתי means: "I have acquired knowledge of something." Similarly, אהבתי means "I am in a state of being in love with something or someone."
We also have stative verbs, which are not the same as verbs of perception or those of emotion. Most if not all stative verbs frequently express an achieved state, e.g. זקנתי = I have become old (translatable "I am old."). That will be true for all the stative verbs. By the way, stative verbs are characterized by a צֵירֵי or חוֹלָם, e.g. כָּבֵד ("He was important.", translatable "He is important.") and יָכֹל ("He was able.", translatable "He is able."), respectively.
Perhaps the construction with a participle rather than finite verb puts emphasis on the ongoing aspect of the action. So, maybe אני יודע means "I am exercising the act of knowing as I speak" while ידעתי simply means "I know" in the sense of "I have acquired knowledge of something."