Robot device and thermal displacement amount estimation device

Abstract

A robot device and a thermal displacement amount estimation device are disclosed. The robot device includes an arm mechanism that includes links and joints. A hand is mounted to a tip of the arm. A motor driver drives motors of the joints. A processor outputs, to the motor driver, a command value for moving a reference point of the hand to a target position. A storage device stores a first thermaldisplacement amount temporal variation representing a variation with respect to a continuous operation time period in a thermal displacement amount by which the hand reference point is displaced froma cool position to a heat balance position due to heat generation accompanying operation of the arm mechanism, and a second thermal displacement amount temporal variation representing a variation with respect to a continuous stopped time period in a thermal displacement amount by which the hand reference point returns from the heat balance position to the cool position accompanying stopping of operation of the arm mechanism. The processor refers to the first and second thermal displacement amount temporal variations to estimate a thermal displacement amount of the hand reference point based on the continuous operation time period and continuous stopped time period of the arm mechanism, and corrects the target position based on the estimated thermal displacement amount.

Description

technical field [0001] Embodiments of the present invention relate to a robot device and a thermal displacement estimation device. Background technique [0002] After the robot is started from the power OFF state, as the operating time elapses, the temperature of the arm mechanism will increase due to the heat generated by the motor itself, which is the power source of the joint, or the frictional heat of the internal structure of the joint, etc. Thermal deformation occurs on the arm mechanism due to thermal expansion. As a result, the tip point of the hand attached to the arm is displaced, resulting in a positional shift with respect to the workpiece. Depending on the application, a displacement of 0.1 mm may also cause a task error. At this time, the deformation of the arm mechanism due to heat cannot be ignored. [0003] As a method of estimating the amount of thermal displacement with high precision, there is known a method of measuring the temperature of multiple part...

AI Technical Summary

Problems solved by technology

[0004] However, in these conventional methods, the workload is increased due to the introduction of the sensor and the installation of the sensor, thereby inevitably increasing the cost.

In addition, the installation environment of the sensor is limited, and the sensor itself may not be installed in some cases.

In addition, due to the alignment error of the sensor, sometimes the expected calibration accuracy cannot be obtained

Furthermore, during operation, the installation position of the sensor may shift or the sensor itself may malfunction suddenly. In this case, it is necessary to interrupt the work and entrust a professional technician to perform the calibration work of thermal displacement correction.

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