Stroke decision device, stroke decision method, recording medium storing stroke decision program, and ball-returning robot

A stroke decision method in which a computer executes processing, the processing comprising:

• acquiring state information including a position, a translational velocity, and a rotational velocity of an incoming ball;
• deciding a stroke condition to control movement of a striking implement of a ball-returning robot which is configured to hit back the incoming ball, the stroke condition including a position, a velocity, and an orientation of the striking implement of the ball-returning robot at a time point of hitting back the ball, based on the state information for the ball and a target arrival position when hitting back the ball with the striking implement;
• and
• sending, via a communication interface, the stroke condition to a control device to control the movement of the striking implement of the ball-returning robot,
• wherein the deciding a stroke condition includes:
• computing trajectory information relating to a predicted trajectory of the incoming ball based on the state information for the ball;
• employing the trajectory information to set a strike position of the ball and to set post-strike state information including a post-strike velocity and a post-strike rotational velocity of the ball immediately after being struck;
• computing a predicted arrival position based on the post-strike state information;
• adjusting the post-strike velocity such that an error between the predicted arrival position and the target arrival position is within a permitted range;
• and
• computing the velocity and the orientation of the striking implement such that the ball will conform to the post-strike state information when the ball conforming to the state information immediately prior to being struck is struck at the strike position.

A non-transitory recording medium storing a stroke decision program that is executable by a computer to perform processing, the processing comprising:

• acquiring state information including a position, a translational velocity, and a rotational velocity of an incoming ball;
• and
• deciding a stroke condition to control movement of a striking implement of a ball-returning robot which is configured to hit back the incoming ball, the stroke condition including a position, a velocity, and an orientation of the striking implement of the ball-returning robot at a time point of hitting back the ball, based on the state information for the ball and a target arrival position when hitting back the ball with the striking implement;
• and
• sending, via a communication interface, the stroke condition to a control device to control the movement of the striking implement of the ball-returning robot,
• wherein the deciding a stroke condition includes:
• computing trajectory information relating to a predicted trajectory of the incoming ball based on the state information for the ball;
• employing the trajectory information to set a strike position of the ball and to set post-strike state information including a post-strike velocity and a post-strike rotational velocity of the ball immediately after being struck;
• computing a predicted arrival position based on the post-strike state information;
• adjusting the post-strike velocity such that an error between the predicted arrival position and the target arrival position is within a permitted range;
• and
• computing the velocity and the orientation of the striking implement such that the ball will conform to the post-strike state information when the ball conforming to the state information immediately prior to being struck is struck at the strike position.

A ball-returning robot, comprising:

• a stroke decision device comprising:
• an acquisition section configured to acquire state information including a position, a translational velocity, and a rotational velocity of an incoming ball;
• and
• a stroke condition decision section configured to decide a stroke condition including a position, a velocity, and an orientation of a striking implement at a time point of hitting back the ball toward a target arrival position, based on the state information for the ball and the target arrival position when hitting back the ball with the striking implement;
• a striking implement configured to hit back an incoming ball;
• a movable section configured to support and move the striking implement;
• and
• a control device configured to control movement of the movable section so as to hit back the ball in accordance with a stroke condition decided by the stroke decision device,
• wherein the stroke condition decision section includes:
• a trajectory prediction section configured to compute trajectory information relating to a predicted trajectory of the incoming ball based on the state information for the ball;
• a setting section configured to employ the trajectory information to set a strike position of the ball and to set post-strike state information including a post-strike velocity and a post-strike rotational velocity of the ball immediately after being struck;
• an arrival position prediction section configured to compute a predicted arrival position based on the post-strike state information;
• an adjustment section configured to adjust the post-strike velocity such that an error between the predicted arrival position and the target arrival position is within a permitted range;
• and
• a stroke condition computation section configured to compute a velocity and an orientation of the striking implement such that the ball will conform to the post-strike state information when the ball conforming to the state information immediately prior to being struck is struck at the strike position.