When a main power source (801) is blocked and a robot control device (300) is unable to be involved, the present invention makes it possible to record, using a robot arm (201) alone, information relating to the state of each joint thereof (J1–J6). The robot arm (201) is provided with: multiple links (211–216); joints (J1–J6) for connecting the multiple links (211–216); and sensors (235, 236) for detecting the state of the joints (J1–J6). The robot arm (201) also is provided with a log-recording device (380) for recording information output from the sensors (235, 236), and an electric supply unit (902) for supplying electric power to the sensors (235, 236) and the log-recording device (380) when the driving power source for the joints (J1–J6) is blocked.
ROBOT ARM, ROBOT CONTROL DEVICE, AND ROBOT SYSTEM