Ship steering control device

A ship steering control device for controlling steering of a ship, the ship including a ship propulsion device configured to generate a propulsion force of the ship and a manual operation unit for manually operating the ship propulsion device, the ship steering control device comprising:

• a manual steering controller configured to control the ship propulsion device, according to a manual operation with respect to the manual operation unit;
• an automatic steering controller configured to automatically control the ship propulsion device, without receiving the manual operation with respect to the manual operation unit;
• an abnormality detection unit configured to detect an abnormality in behavior of the automatic steering controller, wherein the abnormality occurs when a transmission status of communication of signals or information from the automatic steering controller is outside of a predetermined range;
• and
• a steering mode switching unit configured to switch control of the ship propulsion device from control by the automatic steering controller to control by the manual steering controller, in a case where the abnormality is detected by the abnormality detection unit when the ship propulsion device is controlled by the automatic steering controller,
• wherein the manual steering controller is configured to control:
• the ship propulsion device such that a propulsion force of the ship becomes zero, in a case where a position of the manual operation unit is a neutral position;
• the ship propulsion device such that a propulsion force that pushes the ship forward is generated, in a case where the position of the manual operation unit is moved in one direction from the neutral position;
• and
• the ship propulsion device such that the propulsion force that pushes the ship forward increases as a movement amount of the position of the manual operation unit in the one direction from the neutral position increases, and
• the steering mode switching unit includes:
• an automatic steering cancellation unit configured to cancel the control of the ship propulsion device by the automatic steering controller, in a case where the abnormality is detected by the abnormality detection unit;
• a propulsion force reduction controller configured to control the ship propulsion device to reduce the propulsion force of the ship until the propulsion force of the ship becomes zero, after the automatic steering cancellation unit cancels the control of the ship propulsion device by the automatic steering controller;
• an operation position determination unit configured to determine whether the position of the manual operation unit is the neutral position, after the propulsion force of the ship becomes zero under the control of the ship propulsion device by the propulsion force reduction controller;
• and
• a manual steering start unit configured to:
• maintain the propulsion force of the ship at zero, after the propulsion force of the ship becomes zero under the control of the ship propulsion device by the propulsion force reduction controller until the operation position determination unit determines that the position of the manual operation unit is the neutral position;
• and
• start the control of the ship propulsion device by the manual steering controller, after the operation position determination unit determines that the position of the manual operation unit is the neutral position.