Patent ID: 8126593
Filing Date: 2012-02-28
Classification: B25J,G05B

Abstract:
1. An apparatus for detecting a malfunction caused in an electromagnetic brake of a robot, the electromagnetic brake for braking a motor incorporated in the robot, the electromagnetic brake being provided with an excitation coil and being locked when the excitation coil is not excited, the controller comprising: a main relay that has a main contact placed in a current supply path connected from a direct-current power source to the excitation coil and that is operable to open and close the main contact; a sub-relay that has a sub-contact placed between the main contact and the exaction coil in the current supply path; first energization detecting means that detects whether or not the main contact is energized; second energization detecting means that detects whether or not the sub-contact is energized; first control means for controlling the main relay and the sub-relay to open the main contact and the sub-contact when the robot is activated; first detecting means for detecting whether or not the main contact is malfunctioning, by monitoring an energized state of the main contact using the first energization detecting means in response to the control by the first control means, the energization of the main contact showing that the main contact is malfunctioning; second control means for i) stopping activation of the robot when the first detecting means shows that the main contact is malfunctioning and ii) controlling the main relay to close the main contact for a given period of time when the first detecting means shows that the main contact is operating normally, the given period of time being set to a time length that allows the second energization detecting means to detect whether or not the sub-contact is energized; second detecting means for detecting whether or not the sub-contact is malfunctioning, by monitoring an energized state of the sub-contact using the second energization detecting means during the given period of time, the energization of the sub-contact showing that the sub-contact is malfunctioning; and third control means for i) stopping the activation of the robot when the second detecting means shows that the sub-contact is malfunctioning and ii) controlling the main relay to close the main contact when the second detecting means shows that the sub-contact is operating normally.