Blended electrical/friction braking system with electric brake feedback monitor and method of use thereof

Abstract

A blended electrical/friction braking system includes an electric brake feedback monitor which monitors a first signal corresponding to an electric brake effort request of an electric motor of an electrically powered vehicle. The electric brake feedback monitor detects one or more electrical conditions of the electric motor during electric braking and selectively supplies/terminates the first signal to/from a brake controller as a function of the first signal and the one or more electrical conditions. In response to termination of the first signal thereat, the brake controller causes a friction brake of the vehicle to assume the entire braking effort of the vehicle.

We claim:  
     
         1 . A brake feedback monitor for monitoring a first signal corresponding to an electric brake effort request of an electric motor of an electrically powered vehicle, for monitoring one or more electrical conditions of the electric motor in response to the electric brake effort request, and for selectively supplying/terminating the first signal to/from a brake controller as a function of the first signal and the one or more electrical conditions.  
     
     
         2 . The brake feedback monitor as set forth in  claim 1 , further including: 
 a first relay having a contact in series with a path of the first signal, and a first control input for receiving a first control signal which controls the state of the first relay contact; and    a first processor connected for monitoring the first signal, for monitoring the one or more electrical conditions, for converting the monitored one or more electrical conditions into a second signal, for determining if a difference between the first signal and the second signal exceeds a predetermined difference and for supplying the first control signal, wherein the first control signal causes the first relay contact to assume one state when the difference does not exceed the predetermined difference and which causes the first relay contact to assume another state when the difference exceeds the predetermined difference.    
     
     
         3 . The brake feedback monitor as set forth in  claim 2 , further including: 
 a second relay having a contact in series with the path of the first signal, and a first control input for receiving a second control signal which controls the state of the second relay contact; and    a second processor connected for monitoring the first signal, for receiving the second signal from the first processor, for determining if a difference between the first signal and the second signal exceeds a predetermined difference and for supplying the second control signal, wherein the second control signal causes the second relay contact to assume one state when the difference does not exceed the predetermined difference and which causes the second relay contact to assume another state when the difference exceeds the predetermined difference.    
     
     
         4 . The brake feedback monitor as set forth in  claim 3 , wherein: 
 the one state of each relay is the closed state; and    the other state of each relay is the opened state.    
     
     
         5 . The brake feedback monitor as set forth in  claim 4 , wherein: 
 the second relay has a second control input for receiving a third control signal for controlling the state of the second relay contact; and    the first relay has a second control input for receiving a fourth control signal for controlling the state of the first relay contact.    
     
     
         6 . The brake feedback monitor as set forth in  claim 5 , wherein in response to detecting the presence of the first signal after supplying the first control signal for causing the first relay contact to assume its opened state, the first processor supplies the third control signal to the second relay for causing the second relay contact to assume its opened state.  
     
     
         7 . The brake feedback monitor as set forth in  claim 5 , wherein in response to detecting the presence of the first signal after supplying the second control signal for causing the second relay contact to assume its opened state, the second processor supplies the fourth control signal to the first relay for causing the first relay contact to assume its opened state.  
     
     
         8 . The brake feedback monitor as set forth in  claim 5 , wherein: 
 each relay includes a status output which provides a status of the state of the contact thereof, the status output of the first relay is connected to the first processor and the status output of the second relay is connected to the second processor; and    at least one of: 
 (i) after supplying the first control signal for causing the first relay contact to assume its opened state and in response to detecting via the status output of the first relay that the first relay contact is in its closed state, the first processor supplies the third control signal to the second relay for causing the second relay contact to assume its opened state; and  
 (ii) after supplying the second control signal for causing the second relay contact to assume its opened state and in response to detecting via the status output of the second relay that the second relay contact is in its closed state, the second processor supplies the fourth control signal to the first relay for causing the first relay contact to assume its opened state.