9. A communication robot comprising: a body; a head; two arms; two legs; and a controller, each of the head, the two arms, the two legs, and the controller being connected to the body, wherein the controller comprises: a sign language action generating device which creates a sign language action for each word string by connecting skin language actions for each word used in a skin language performed by a robot, the robot including, as parts thereof, a body, a head, two arms, two legs, and a controller, each of the latter four parts being connected to the body, the sign language action generating device comprising: a storage unit that stores therein a sign language word database in which a sign language action data which is previously created such that, in units of words, no interference is generated between the parts of the robot used for performing a skin language, the skin language action data being stored in association with a word having the same meaning as a sign language action corresponding thereto; a word string input unit into which a word string is inputted; a trace creation unit that extracts, from the sign language word database, a data on a sign language action for each pair of words which is constituted by two successive words in the word string inputted into the word string input unit, and creates, for the each pair of words, a trace which connects between an end point position of a sign language action having the same meaning as a prior word of the pair of words and a start point position of a sign language action having the same meaning as a posterior word thereof, based on the extracted skin language action data; an interference determination unit that determines that interference is generated between the parts of the robot used when the robot performs a sign language, if a distance between the parts on each of the created traces is not within a prescribed allowable range; an action connection unit that connects sign language actions for words via the traces created in accordance with the inputted word strings such that no interference is generated between the parts of the robot; and an action adjustment unit that, if the interference is determined to be generated between any of the parts of the robot on the trace created for a pair of words, adjusts a position coordinate or a velocity as a sign language action for the pair of words so as to keep the position coordinate or the velocity within an allowable range as well as within a prescribed threshold range which is previously set such that meanings of both the prior word and the posterior word of the pair of words as the skin language action can be maintained; an action determination unit that determines a sign language action to be expressed and inputs a word string representing the determined sign language action, into the sign language action generating device; and an action execution unit that executes the sign language action having the same meaning as the inputted word string, based on the sign language action for each word string generated by the sign language action generating device.
10. The communication robot according to claim 9 , wherein the action adjustment unit adjusts a position coordinate or a velocity using, as the prescribed threshold range, a threshold range of a shift amount of a prescribed position coordinate or a prescribed velocity, or a threshold range of an evaluation function calculated based on the shift amount.