Robot device controller for controlling position of robot

A controller for a robot device in which a robot moves a second member so as to adjust a relative position of the second member with respect to a first member, comprising:

• a visual sensor mounted on the robot;
• and
• a processor configured to:
• in a first control,
• obtain a reference image captured by the visual sensor in a state where the second member is arranged at a target position with respect to the first member, the reference image including images of a first characteristic portion of the first member and a second characteristic portion of the second member;
• detect a position of the first characteristic portion of the first member and a position of the second characteristic portion of the second member in the reference image;
• and
• calculate, as a first relative position amount, a difference between coordinate values of the position of the first characteristic portion and coordinate values of the position of the second characteristic portion in the reference image,
• the processor is further configured to:
• in a second control,
• obtain an image captured by the visual sensor in a state where the second member is arranged with respect to the first member, the image including images of the first characteristic portion of the first member and the second characteristic portion of the second member;
• detect a position of the first characteristic portion of the first member and a position of the second characteristic portion of the second member in the image;
• calculate, as a second relative position amount, a difference between coordinate values of the first characteristic portion and coordinate values of the second characteristic portion in the image;
• generate a movement command for operating the robot to move the second member to the target position with respect to the first member based on the first relative position amount and the second relative position amount;
• and
• operate the robot so that a position of the second member is adjusted to the target position with respect to the first member based on the movement command,
• wherein
• in the image captured by the visual sensor mounted on the robot, the coordinate values of the position of the second characteristic portion are constant,
• the processor is further configured to:
• repeat the second control so that the position of the second member approaches the target position with respect to the first member;
• store the coordinate values of the position of the second characteristic portion in a storage device when the position of the second characteristic portion is detected in the image captured by the visual sensor for a first time in repetition of the second control;
• and
• use the coordinate values of the position of the second characteristic portion stored in the storage device to calculate the second relative position amount for images captured by the visual sensor for second and subsequent times in the repetition of the second control.