1. Technical Field
The present invention relates to a robot capable of moving a terminal device, which is attached to a front end of an arm, to a wanted position, a carriage device capable of moving the terminal device, which is attached to the movable member, to a wanted position, and a control method using an inertia sensor to control these devices.
2. Related Art
In the past, it has been widely known an apparatus such as a robot capable of moving a terminal device, which is attached to a front end of an arm by pivoting the arm and so on, to a wanted position and operating the terminal device at the position. For example, there are known a feeding/releasing material device having a gripping terminal and feeding and releasing a matching target part to and from a machining apparatus, an applicator robot having an applicator terminal, a welding robot having a welding terminal or the like.
When the robot is driven, a control method is used, in which a pivot angle of a driving source such as a motor for driving a robot arm is measured, a position of a front end of the arm or the like is controlled based on information on the measured angle. However, since a transmission mechanism for transmitting a driving force to the arm from the driving source or the arm is not made of a rigid body, the transmission mechanism or the arm is deformed. As a result, there is a case in which the position of the front end side of the arm, of which the position is controlled based on the angle information, does not necessarily coincide with an actual position. In addition, there is a problem in that vibration is generated since the transmission mechanism or the arm is deformed upon the operation. In order to solve the problem, a method is devised in which an inertia sensor is attached to the front end of the arm to measure the movement of the front end and thus control the angular velocity information obtained by the inertia sensor. JP-A-7-9374 discloses a control method for an articulated robot and an articulated robot capable of determining a position with high precision in a case in which rigidity is low and preventing the precision from being deteriorated due to vibration, by controlling operation of the arm using an output signal of the inertia sensor.
However, in order to obtain a pivot angle of an arm from the output of the inertia sensor, it is necessary to integrate the output of the inertia sensor. In addition, there is a problem in that if the integration is repeated, it is liable to receive an effect of a drift of a reference potential of the inertia sensor, so that a control device is capable of highly misrecognizing the information. In JP-A-2005-242794, a robot control device and a robot control method are disclosed to preclude an error factor which is varied in a low frequency, such as a drift of the reference potential, by using a low frequency component from an output of an angle sensor, in which an output of an angular velocity sensor is used to control a high frequency component only which is an integral value of the output.
However, there is a problem in that an error due to the effect of the noise, the effect in delay of signal transmission or the like is possibly contained in the output of the inertia sensor, and thus the control device easily misrecognizes the information due to the error. Since the effect from the noise of the inertia sensor or the effect from the delay of the signal transmission is a phenomenon which happens even in a high frequency, the control device or the control method disclosed in JP-A-2005-242794 cannot cope with the problem.