Vehicle suspension control system and suspension control method

Abstract

When a vehicle approaches a corner, a microprocessor, responsive to a determination that a detected degree of roughness of the road surface corresponds to the most moderate roughness, sets the damping force for the vehicle suspension units, on the basis of the detected degree of roughness, vehicle speed and a radius of curvature and corner information from a navigation system. In the case of a determination that the detected degree of roughness does not correspond to the most moderate roughness, a damping level is set on the basis of the detected degree of roughness, vehicle speed and radius of curvature.

1 . A suspension control system for a vehicle equipped with a navigation system, said suspension control unit comprising: 
 suspension means, interposed between a wheel support member and a frame portion of the vehicle, for creating a damping force;    roughness detecting means for detecting a degree of roughness of a road surface traveled by the vehicle;    speed detecting means for detecting traveling speed of the vehicle;    cornering detecting means for detecting cornering by the vehicle;    entrance determining means for determining whether or not the vehicle has entered a turn around a corner based on output of the cornering detecting means;    good-road adjustment calculating means for, responsive to approach of the vehicle to the corner and to detection of a degree of roughness corresponding to a good road surface, calculating a good-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and corner information from the navigation system;    bad-road adjustment calculating means for, responsive to approach of the vehicle to the corner and to detection of a degree of roughness which does not correspond to a good road surface, determining if the vehicle has entered the turn around the corner and, if the vehicle is determined to have entered the turn around the corner, calculating a bad-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and corner information from the navigation system; and    output means for outputting to the suspension means the good-road adjustment or the bad-road adjustment for adjustment of the damping force of the suspension means.    
   
   
       2 . A suspension control system according to  claim 1  wherein: 
 when the vehicle enters the turn around the corner with the damping force of the suspension means set in accordance with the good-road adjustment, responsive to detection of a degree of roughness no longer corresponding to a good road surface, said bad-road adjustment calculating means calculates a bad-road adjustment and said output means outputs the calculated bad-road adjustment to the suspension means for adjusting the damping force.    
   
   
       3 . A suspension control system for a vehicle equipped with a navigation system, said suspension control unit comprising: 
 suspension means, interposed between a wheel support member and a frame portion of the vehicle, for creating a damping force;    roughness detecting means for detecting a degree of roughness of a road surface traveled by the vehicle;    speed detecting means for detecting traveling speed of the vehicle;    good-road adjustment calculating means for, responsive to approach of the vehicle to the corner and to detection of a degree of roughness corresponding to a good road surface, calculating a good-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and corner information from the navigation system;    normal-travel adjustment calculating means, responsive to a change in the detected degree of roughness from a degree of roughness corresponding to a good road surface to a degree of roughness not corresponding to a good road surface, calculating a normal-travel adjustment on the basis of the detected degree of roughness; and    output means for outputting to the suspension means the good-road adjustment amount or the normal travel adjustment for adjustment of the damping force of the suspension means.    
   
   
       4 . A suspension control system for a vehicle equipped with a navigation system, said suspension control unit comprising: 
 suspension means, interposed between a wheel support member and a frame portion of the vehicle, for creating a damping force;    roughness detecting means for detecting a degree of roughness of a road surface traveled by the vehicle;    speed detecting means for detecting traveling speed of the vehicle;    normal-travel adjustment calculating means for, responsive to approach of the vehicle to a corner and detection of a degree of roughness which does not correspond to a good road surface, calculating a normal-travel adjustment on the basis of the detected degree of roughness;    good-road adjust amount calculating means for, responsive to detection of a degree of roughness which no longer corresponds to a good road surface, calculating a good-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and corner information from the navigation system; and    output means for outputting to the suspension means the normal-travel adjustment or the good-road adjustment for adjustment of the damping force of the suspension means.    
   
   
       5 . A suspension control system for a vehicle equipped with a navigation system, said suspension control unit comprising: 
 suspension means, interposed between a wheel support member and a frame portion of the vehicle, for creating a damping force;    roughness detecting means for detecting a degree of roughness of a road surface traveled by the vehicle;    speed detecting means for detecting traveling speed of the vehicle;    cornering detecting means for detecting cornering by the vehicle;    entrance determining means for determining whether or not the vehicle has entered a turn around a corner based on output of the cornering detecting means;    normal-travel adjustment calculating means for, responsive to approach of the vehicle to the corner and detection of a degree of roughness which does not correspond to a good road surface, calculating a normal-travel adjustment on the basis of the detected degree of roughness;    bad-road adjustment calculating means for, responsive to a determination that the detected degree of roughness remains not corresponding to a good road surface upon entry of the vehicle into the turn around the corner, calculating a bad-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and corner information from the navigation system; and    output means for outputting to the suspension means the normal-travel adjustment or the bad-road adjustment for adjustment of the damping force of the suspension means.    
   
   
       6 . A suspension control system according to  claim 5 , wherein at least one of the adjustment calculating means extracts a roughness component at a predetermined frequency from signals from the roughness detecting means and calculates an adjustment of the suspension means on the basis of the extracted roughness component.  
   
   
       7 . A suspension control system according to  claim 1 , wherein at least one of the adjustment calculating means extracts a roughness component at a predetermined frequency from signals from the roughness detecting means and calculates an adjustment of the suspension means on the basis of the extracted roughness component.  
   
   
       8 . A suspension control system according to  claim 3 , wherein at least one of the adjustment calculating means extracts a roughness component at a predetermined frequency from signals from the roughness detecting means and calculates an adjustment of the suspension means on the basis of the extracted roughness component.  
   
   
       9 . A suspension control system according to  claim 4 , wherein at least one of the adjustment calculating means extracts a roughness component at a predetermined frequency from signals from the roughness detecting means and calculates an adjustment of the suspension means on the basis of the extracted roughness component.  
   
   
       10 . A suspension control system for a vehicle equipped with a navigation system, said suspension control system comprising: 
 suspension means, interposed between a wheel support member and a frame portion of the vehicle, for creating a damping force;    slip detecting means for detecting a degree of slip of a road surface traveled by the vehicle;    vehicle-speed detecting means for detecting vehicle speed;    cornering detecting means for detecting cornering by the vehicle;    entrance determining means for determining whether or not the vehicle has entered a turn around a corner based on output of the cornering detecting means;    good-road adjustment calculating means for, responsive to approach of the vehicle to the corner and to detection of a degree of slip corresponding to a good road surface, calculating a good-road adjustment on the basis of the detected degree of slip, the detected vehicle speed and corner information from the navigation system;    bad-road adjustment calculating means for, responsive to approach of the vehicle to the corner and to detection of a degree of slip which does not correspond to a good road surface, determining if the vehicle has entered the turn around the corner, and, if the vehicle is determined to have entered the turn around the corner, calculating a bad-road adjustment on the basis of the detected degree of slip, the detected vehicle speed and corner information from the navigation system; and    output means for outputting to the suspension means the good-road adjustment amount or the bad-road adjustment for adjustment of the damping force of the suspension means.    
   
   
       11 . A suspension control system according to  claim 10  wherein: 
 when the vehicle enters the turn around the corner with the damping force of the suspension means set in accordance with the good-road adjustment, responsive to detection of a degree of slip no longer corresponding to a good road surface, said bad-road adjustment calculating means calculates a bad-road adjustment and said output means outputs the calculated bad-road adjustment to the suspension means for adjusting the damping force.    
   
   
       12 . A suspension control system for a vehicle equipped with a navigation system, said suspension control system comprising: 
 suspension means, interposed between a wheel support member and a frame portion of the vehicle, for creating a damping force;    slip detecting means for detecting a degree of slip of a road surface traveled by the vehicle;    vehicle-speed detecting means for detecting vehicle speed;    good-road adjustment calculating means for, responsive to approach of the vehicle to the corner and to detection of a degree of slip corresponding to a good road surface, calculating a good-road adjustment on the basis of the detected degree of slip, the detected vehicle speed and corner information from the navigation system;    normal-travel adjustment calculating means for, responsive to detection of a degree of slip which no longer corresponds to a good road surface, calculating a normal-travel adjustment on the basis of the detected degree of slip; and    output means for outputting to the suspension means the normal-travel adjustment or the good-road adjustment for adjustment of the damping force of the suspension means.    
   
   
       13 . A suspension control system for a vehicle equipped with a navigation system, said suspension control system comprising: 
 suspension means, interposed between a wheel support member and a frame portion of the vehicle, for creating a damping force;    slip detecting means for detecting a degree of slip of a road surface traveled by the vehicle;    vehicle-speed detecting means for detecting vehicle speed;    normal-travel adjustment amount calculating means for, responsive to approach of the vehicle to the corner and to detection of a degree of slip which does not correspond to a good road surface state of the traveling road surface, calculating a normal-travel adjustment amount on the basis of the detected degree of slip;    good-road adjustment calculating means for, responsive to detection of a degree of slip which thereafter corresponds to a good road surface, calculating a good-road adjustment on the basis of the detected degree of slip, the detected vehicle speed and corner information from the navigation system; and    output means for outputting to the suspension means the normal-travel adjustment or the good-road adjustment for adjustment of the damping force of the suspension means.    
   
   
       14 . A suspension control system for a vehicle equipped with a navigation system, said suspension control system comprising: 
 suspension means, interposed between a wheel support member and a frame portion of the vehicle, for creating a damping force;    slip detecting means for detecting a degree of slip of a road surface traveled by the vehicle;    vehicle-speed detecting means for detecting vehicle speed;    cornering detecting means for detecting cornering by the vehicle;    entrance determining means for determining whether or not the vehicle has entered a turn around a corner based on output of the cornering detecting means;    normal-travel adjustment amount calculating means for, responsive to approach of the vehicle to the corner and to detection of a degree of slip which does not correspond to a good road surface state of the traveling road surface, calculating a normal-travel adjustment on the basis of the detected degree of slip;    bad-road adjustment calculating means for, responsive to determination of entrance of the vehicle to the turn around the corner and responsive to detection of a degree of slip which no longer corresponds to a good road surface, calculating a bad-road adjustment on the basis of the detected degree of slip, the detected vehicle speed and corner information from the navigation system; and    output means for outputting to the suspension means the normal-travel adjustment or the bad-road adjustment for adjustment of the damping force of the suspension means.    
   
   
       15 . A suspension control system according to  claim 14 , wherein at least one of the adjustment calculating means determines a slip component at a predetermined frequency from signals from the slip state detecting means and calculates an adjustment for the suspension means on the basis of the slip component thus determined.  
   
   
       16 . A suspension control system according to  claim 10 , wherein at least one of the adjustment calculating means determines a slip component at a predetermined frequency from signals from the slip state detecting means and calculates an adjustment for the suspension means on the basis of the slip component thus determined.  
   
   
       17 . A suspension control system according to  claim 12 , wherein at least one of the adjustment calculating means determines a slip component at a predetermined frequency from signals from the slip state detecting means and calculates an adjustment for the suspension means on the basis of the slip component thus determined.  
   
   
       18 . A suspension control system according to  claim 13 , wherein at least one of the adjustment calculating means determines a slip component at a predetermined frequency from signals from the slip state detecting means and calculates an adjustment for the suspension means on the basis of the slip component thus determined.  
   
   
       19 . A suspension control method for a vehicle equipped with a navigation system and suspension means, said method comprising: 
 detecting vehicle speed;    detecting current position of the vehicle;    determining approach of the vehicle to a corner;    detecting a degree of roughness of the road surface at the detected current position;    responsive to a determination that the vehicle is approaching the corner and to detection of a degree of roughness of the road surface at the detected current position corresponding to a good road surface, calculating a good-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and corner information from the navigation system;    determining whether or not the vehicle has entered a turn around the corner;    responsive to the vehicle approaching the corner and a detected degree of roughness at the detected current position of the vehicle no longer corresponding to a good road surface, determining if the vehicle has entered a turn around the corner, and, if the vehicle has entered the turn around the corner, calculating a bad-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and the corner information from the navigation system;    outputting to the suspension means the good-road adjustment or the bad-road adjustment for control of the damping force of the suspension means.    
   
   
       20 . A suspension control method according to  claim 19  wherein, when the vehicle enters the turn around the corner with the damping force of the suspension means set in accordance with the good-road adjustment, responsive to detection of a degree of roughness no longer corresponding to a good road surface, calculating a bad-road adjustment and outputting the calculated bad-road adjustment to the suspension means for adjusting the damping force.  
   
   
       21 . A suspension control method for a vehicle equipped with a navigation system and suspension means, said method comprising: 
 detecting vehicle speed;    detecting current position of the vehicle;    detecting a degree of roughness of the road surface at the detected current position;    responsive to the vehicle approaching a corner and detection of a degree of roughness of the road surface at the detected current position corresponding to a good road surface, calculating a good-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and corner information from the navigation system;    responsive to the detected roughness state thereafter no longer corresponding to a good road surface, calculating a normal-travel adjustment on the basis of the detected degree of roughness; and    outputting to the suspension means the good-road adjustment or the normal-travel adjustment for adjustment of the damping force of the suspension means.    
   
   
       22 . A suspension control method for a vehicle equipped with a navigation system and suspension means, said method comprising: 
 detecting vehicle speed;    detecting current position of the vehicle;    detecting a degree of roughness of the road surface at the detected current position;    responsive to the vehicle approaching a corner and detection of a degree of roughness of the road surface, at the detected current position, not corresponding to a good road surface, calculating a normal-travel adjustment on the basis of the detected degree of roughness;    responsive to a detected degree of roughness which thereafter corresponds to a good road surface, calculating a good-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and corner information from the navigation system; and    outputting to the suspension means the normal-travel adjustment or the good-road adjustment for control of damping force of the suspension means.    
   
   
       23 . A suspension control method for a vehicle equipped with a navigation system, said method comprising: 
 detecting vehicle speed;    detecting a current position of the vehicle;    detecting a degree of roughness of the road surface at the detected current position;    responsive to approach of a vehicle to a corner and detection of a degree of roughness of the road surface at the detected current position of the vehicle which does not correspond to a good road surface, calculating a normal-travel adjustment on the basis of the detected degree of roughness;    determining whether or not the vehicle has entered into a turn around the corner;    after entrance into the turn around the corner, responsive to a change in the detected degree of roughness from a degree of roughness corresponding to a good road surface to a degree of roughness not corresponding to a good road surface, calculating a bad-road adjustment on the basis of the detected degree of roughness, the detected vehicle speed and corner information from the navigation system; and    outputting to the suspension means the normal-travel adjustment or the bad-road adjustment for control of the damping force of the suspension means.    
   
   
       24 . A suspension control method for a vehicle equipped with a navigation system, said method comprising: 
 detecting vehicle speed;    detecting a current position of the vehicle;    detecting a slip state of the road surface at the detected current position of the vehicle;    responsive to the vehicle approaching a corner and to detection of a slip state corresponding to a good road surface, calculating a good-road adjustment on the basis of the detected slip state, the detected vehicle speed and corner information from the navigation system;    determining whether or not the vehicle has entered into a turn around the corner;    responsive to a determination that the vehicle is approaching the corner and to detection of a slip state of the road surface at the detected current position of the vehicle which does not correspond to a good road surface, if the vehicle is determined to have entered into the turn around the corner, calculating a bad-road adjustment on the basis of the detected slip state, the detected vehicle speed and the corner information from the navigation system; and    outputting to the suspension means the good-road adjustment or the bad-road adjustment for control of the damping force of the suspension means.    
   
   
       25 . A suspension control method for a vehicle equipped with a navigation system and suspension means, said method comprising: 
 detecting vehicle speed;    detecting a current position of the vehicle;    detecting a slip state of the road surface at the detected current position of the vehicle;    responsive to the vehicle approaching a corner and detection of a slip state of the road surface at the detected current position which corresponds to a good road surface, calculating a good-road adjustment on the basis of the detected slip state, the detected vehicle speed and corner information from the navigation system;    determining whether or not the vehicle has entered into the turn around the corner;    responsive to detection of a slip state which no longer corresponds to a good road surface and to determination of entry of the vehicle into the turn around the corner, calculating a bad-road adjustment on the basis of the detected slip state, the detected vehicle speed and the corner information from the navigation system; and    outputting to the suspension means the good-road adjustment or the bad-road adjustment for control of the damping force of the suspension means.    
   
   
       26 . A suspension control method for a vehicle equipped with a navigation system and suspension means, said method comprising: 
 detecting vehicle speed;    detecting a current position of the vehicle;    detecting a slip state of the road surface at the detected current position of the vehicle;    responsive to the vehicle approaching a corner and detection of a slip state of the road surface at the detected current position which corresponds to a good road surface, calculating a good-road adjustment on the basis of the detected slip state, the detected vehicle speed and corner information from the navigation system;    responsive to detection of a slip state which no longer corresponds to the good road surface, calculating a normal-travel adjustment on the basis of the detected slip state; and    outputting to the suspension means the good-road adjustment or the normal-travel adjustment for control of the damping force of the suspension means.    
   
   
       27 . A suspension control method for a vehicle equipped with a navigation system and suspension means, said method comprising: 
 detecting vehicle speed;    detecting a current position of the vehicle;    detecting a slip state of the road surface at the detected current position of the vehicle;    responsive to the vehicle approaching a corner and detection of a slip state of the road surface at the detected current position of the vehicle which does not correspond to a good road surface, calculating a normal-travel adjustment on the basis of the detected slip state;    responsive to detection thereafter of a slip state which corresponds to the good road surface, calculating a good-road adjustment on the basis of the detected slip state, the detected vehicle speed and corner information from the navigation system; and    outputting to the suspension means good-road adjustment or the normal-travel adjustment for control of the damping force of the suspension means.    
   
   
       28 . A suspension control method for a vehicle equipped with a navigation system and suspension means, said method comprising: 
 detecting vehicle speed;    detecting a current position of the vehicle;    detecting a slip state of the road surface at the detected current position of the vehicle;    responsive to the vehicle approaching a corner and detection of a slip state of the road surface at the detected current position of the vehicle which does not correspond to a good road surface, calculating a normal-travel adjustment on the basis of the detected slip state alone;    determining whether or not the vehicle has entered into a turn around the corner;    responsive to a determination that the detected slip state remains not corresponding to the good road surface upon entry of the vehicle into the turn around the corner, calculating a bad-road adjustment on the basis of the detected slip state, the detected vehicle speed and corner information from the navigation system; and    outputting to the suspension means a normal-travel adjustment or a bad-road adjustment for control of the damping force of the suspension means.    
   
   
       29 . A suspension control system according to  claim 14 , wherein the normal travel adjustment is calculated only after a determination that the vehicle has not entered the turn around the corner.  
   
   
       30 . A suspension control method according to  claim 21  wherein the normal travel adjustment is calculated only after a determination that the vehicle has not started the turn around the corner.  
   
   
       31 . A suspension control method according to  claim 22 , wherein the normal travel adjustment is calculated only after a determination that the vehicle has not entered the turn around the corner.  
   
   
       32 . A suspension control method according to  claim 26 , wherein the normal travel adjustment is calculated only after a determination that the vehicle has not entered the turn around the corner.  
   
   
       33 . A suspension control method according to  claim 27 , wherein the normal travel adjustment is calculated only after a determination that the vehicle has not entered the turn around the corner.