System for and method of controlling behavior of watercraft

Abstract

A system includes a marine propulsion device, an actuator, a pitch angle sensor, a trim angle sensor, and a controller to obtain at least either of a pitch angle of a watercraft or an angular velocity of the pitch angle, and to obtain a trim angle of the marine propulsion device. The controller is configured or programmed to selectively set either a trim-up direction or a trim-down direction as a trim direction based on the trim angle of the marine propulsion device and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle. The controller is configured or programmed to control the actuator to cause the marine propulsion device to perform a trim motion in the trim direction.

What is claimed is: 
     
         1 . A system for controlling a behavior of a watercraft, the system comprising:
 a marine propulsion device including a trim shaft and that is pivotably attachable to the watercraft about the trim shaft;   an actuator to cause the marine propulsion device to perform a trim motion in a trim-up direction and a trim-down direction by causing the marine propulsion device to pivot about the trim shaft;   a pitch angle sensor to detect at least either of a pitch angle of the watercraft or an angular velocity of the pitch angle;   a trim angle sensor to detect a trim angle of the marine propulsion device; and   a controller communicably connected to the actuator and configured or programmed to:
 obtain the at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle; 
 obtain the trim angle of the marine propulsion device; 
 selectively set either the trim-up direction or the trim-down direction as a trim direction based on the trim angle of the marine propulsion device and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle; and 
 control the actuator to cause the marine propulsion device to perform the trim motion in the trim direction. 
   
     
     
         2 . The system according to  claim 1 , wherein the controller is configured or programmed to:
 calculate a parameter based on the trim angle of the marine propulsion device and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle, the parameter periodically varying during an occurrence of porpoising of the watercraft; and   selectively set either the trim-up direction or the trim-down direction as the trim direction based on the parameter.   
     
     
         3 . The system according to  claim 2 , wherein the parameter periodically varies between a first value and a second value; and the controller is configured or programmed to:
 set the trim-up direction as the trim direction when the parameter becomes the first value; and   set the trim-down direction as the trim direction when the parameter becomes the second value.   
     
     
         4 . The system according to  claim 1 , wherein the controller is configured or programmed to control the actuator to cause the marine propulsion device to perform the trim motion in the trim direction when it is determined that the pitch angle or the angular velocity of the pitch angle periodically varies at about 0.1 Hz or greater. 
     
     
         5 . A system for controlling a behavior of a watercraft, the system comprising:
 a posture control body attachable to the watercraft so that a position of the posture control body is changeable relative to the watercraft, the posture control body configured to change a lift force acting on the watercraft by changing the position of the posture control body;   a first actuator to move the posture control body in a first increasing direction to increase the lift force and in a first decreasing direction to decrease the lift force;   a pitch angle sensor to detect at least either of a pitch angle of the watercraft or an angular velocity of the pitch angle;   a position sensor to detect the position of the posture control body; and   a controller communicably connected to the first actuator and configured or programmed to:
 obtain at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle; 
 obtain the position of the posture control body; 
 selectively set either the first increasing direction or the first decreasing direction as a first movement direction of the posture control body based on the position of the posture control body and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle; and 
 control the first actuator to move the posture control body in the first movement direction. 
   
     
     
         6 . The system according to  claim 5 , wherein the controller is configured or programmed to:
 calculate a parameter based on the position of the posture control body and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle, the parameter periodically varying during an occurrence of porpoising of the watercraft; and   selectively set either the first increasing direction or the first decreasing direction as the first movement direction based on the parameter.   
     
     
         7 . The system according to  claim 6 , wherein
 the parameter periodically varies between a first value and a second value; and   the controller is configured or programmed to:
 set the first decreasing direction as the first movement direction when the parameter becomes the first value; and 
 set the first increasing direction as the first movement direction when the parameter becomes the second value. 
   
     
     
         8 . The system according to  claim 5 , wherein the controller is configured or programmed to control the first actuator to cause the posture control body to move in the first movement direction when it is determined that the pitch angle or the angular velocity of the pitch angle periodically varies at about 0.1 Hz or greater. 
     
     
         9 . The system according to  claim 5 , further comprising:
 a marine propulsion device attachable to the watercraft so that a position of the marine propulsion device is changeable relative to the watercraft; and   a second actuator to move the marine propulsion device in a second increasing direction to increase a lift force of the marine propulsion device on the watercraft and in a second decreasing direction to decrease a lift force of the marine propulsion device acting on the watercraft; wherein   the controller is configured or programmed to:
 selectively set either the second increasing direction or the second decreasing direction as a second movement direction of the marine propulsion device based on the position of the marine propulsion device and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle; and 
 control the second actuator to move the marine propulsion device in the second movement direction. 
   
     
     
         10 . The system according to  claim 9 , wherein the controller is configured or programmed to:
 calculate a parameter based on the position of the marine propulsion device and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle; the parameter periodically varying during an occurrence of porpoising of the watercraft; and   selectively set either the second increasing direction or the second decreasing direction as the second movement direction based on the parameter.   
     
     
         11 . The system according to  claim 10 , wherein
 the parameter periodically varies between a first value and a second value; and   the controller is configured or programmed to:
 set the second decreasing direction as the second movement direction when the parameter becomes the first value; and 
 set the second increasing direction as the second movement direction when the parameter becomes the second value. 
   
     
     
         12 . The system according to  claim 9 , wherein the controller is configured or programmed to control the second actuator to cause the marine propulsion device to move in the second movement direction when it is determined that the pitch angle or the angular velocity of the pitch angle periodically varies at about 0.1 Hz or greater. 
     
     
         13 . A system for controlling a behavior of a watercraft, the system comprising:
 a posture control body attachable to the watercraft so that a position of the posture control body is changeable relative to the watercraft, the posture control body configured to change a lift force acting on the watercraft by changing the position of the posture control body;   a first actuator to move the posture control body in a first increasing direction to increase the lift force and in a first decreasing direction to decrease the lift force;   a marine propulsion device attachable to the watercraft so that a position of the marine propulsion device is changeable relative to the watercraft;   a second actuator to move the marine propulsion device in a second increasing direction to increase the lift force and in a second decreasing direction to decrease the lift force;   a pitch angle sensor to detect at least either of a pitch angle of the watercraft or an angular velocity of the pitch angle;   a first sensor to detect the position of the posture control body;   a second sensor to detect the position of the marine propulsion device; and   a controller communicably connected to the first actuator and the second actuator, and configured or programmed to:
 obtain at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle; 
 obtain the position of the posture control body; 
 obtain the position of the marine propulsion device; 
 move at least either of the posture control body or the marine propulsion device to alleviate porpoising of the watercraft; 
 selectively set either the first increasing direction or the first decreasing direction as a first movement direction of the posture control body based on the position of the posture control body and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle, and control the first actuator to move the posture control body in the first movement direction; and 
 selectively set either the second increasing direction or the second decreasing direction as a second movement direction of the marine propulsion device based on the position of the marine propulsion device and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle, and control the second actuator to move the marine propulsion device in the second movement direction. 
   
     
     
         14 . The system according to  claim 13 , wherein the controller is configured or programmed to:
 calculate a parameter based on the position of the posture control body or the position of the marine propulsion device and at least either of the pitch angle of the watercraft or the angular velocity of the pitch angle, the parameter periodically varying during an occurrence of porpoising of the watercraft;   selectively set either the first increasing direction or the first decreasing direction as the first movement direction of the posture control body based on the parameter; and   selectively set either the second increasing direction or the second decreasing direction as the second movement direction of the marine propulsion device based on the parameter.   
     
     
         15 . The system according to  claim 14 , wherein
 the parameter periodically varies between a first value and a second value; and   the controller is configured or programmed to:
 when moving the posture control body, set the first decreasing direction as the first movement direction when the parameter becomes the first value, and set the first increasing direction as the first movement direction when the parameter becomes the second value; and 
 when moving the marine propulsion device, set the second decreasing direction as the second movement direction when the parameter becomes the first value, and set the second increasing direction as the second movement direction when the parameter becomes the second value. 
   
     
     
         16 . The system according to  claim 13 , wherein the controller is configured or programmed to:
 when moving the posture control body, control the first actuator to cause the posture control body to move in the first movement direction upon determining that the pitch angle or the angular velocity of the pitch angle periodically varies at about 0.1 Hz or greater; and   when moving the marine propulsion device, control the second actuator to cause the marine propulsion device to move in the second movement direction upon determining that the pitch angle or the angular velocity of the pitch angle periodically varies at about 0.1 Hz or greater.