Patent Abstract:
An interface system prevents operational interference between a vehicle power door and a ramp of an access system by interrupting power to the motors and actuators responsible for operating the door. The interface system includes a relay system that does not interrupt, read, signal, or otherwise interfere with the communication lines between a body control unit, door control unit, or remote control transmitter or receiver. Thus, the interface system functions without the need to receive and transmit signals on the vehicle&#39;s communication bus. The interface system enables the ramp controller of the access system to be a separate module, which controls the ramp and kneel functions, because the only input the ramp controller provides to the power door system is to a ground signal that mimics that of a switch included in the vehicle.

Full Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Patent Application No. PCT/US2007/069284, filed May 18, 2007, which is a continuation of U.S. patent application Ser. No. 11/436,458, filed May 18, 2006, now U.S. Pat. No. 7,417,395. The entire contents of these applications are incorporated by reference herein. 
    
    
     BACKGROUND 
     Access systems, such as motorized lifts, have been used to transport people and cargo. These access systems include platforms, ramps, moving seats, movable steps, and the like, which may be attached to stationary structures, such as buildings and loading docks, or mobile structures such as vehicles. Access systems have been used to provide disabled individuals access to structures that traditionally were accessible only via steps or stairs, or required an individual to step over or across an obstacle. For example, motorized lifts have been used to allow disabled individuals to enter and exit vehicles. In another example, motorized lifts have been used to load and/or unload stretchers from vehicles, such as ambulances. Motorized lifts have also been used on loading docks and trucks to allow cargo to be loaded, unloaded or otherwise moved. 
     When an access system is installed in a vehicle that includes a power sliding door, the access system may be configured to interface with the power sliding door system of the vehicle. As understood in the industry, components, such as power sliding doors, that are installed in the vehicle by the vehicle manufacturer are referred to as OEM components. The OEM power sliding door system opens or closes the door when it receives a request to do so (a “door operation request”). Some power sliding door systems include a body control unit, a door control unit, a receiver, various door switches, and a data bus. The body control unit, door control unit, receiver and at least some of the door switches are in communication with the vehicle&#39;s data bus, which enables various vehicle components to communicate with each other, for example, to receive a signal from a user indicating that the user wants to open or close the door (a “door operation request”). 
     Depending upon the specific vehicle, the user may communicate a door operation request to the power door system by pulling on a door handle of the vehicle, depressing one of the door switches located throughout the vehicle, or by pushing a button on a keyless entry device. If the door operation request is produced by the keyless entry device, the request is often received by the remote receiver, transmitted to the body control unit, and if appropriate, communicated to the door control unit over the data bus. If the door operation request is produced by movement of the door handle, the door operation request is often communicated directly to the door control unit, but will only be executed (e.g. by opening or closing the door) if appropriate vehicle conditions are detected by the body control unit. If the door operation request is produced by movement of one of the door switches located throughout the vehicle, depending upon the specific switch, the door operation request may be communicated directly to the body control unit, or may be communicated to the body control unit or to the door control unit via the data bus. Once the door operation request reaches the body control unit or the door control unit, the door operation request is managed in the manner discussed above. 
     As mentioned, door operation requests will only be executed if the body control unit determines that vehicle conditions are satisfactory to allow operation of the door. For example, the body control unit may receive signals via the data bus indicating the status of the transmission position, speed and door lock position of the vehicle. If the body control unit determines that vehicle conditions are acceptable (e.g. the vehicle is in park), the body control unit communicates an authorization command to the door control unit so that the door control unit will operate to move the door in response to receiving a door operation request. The door control unit operates to move the door by supplying electrical power to motors, clutches and actuators that unlatch, and open or close the door. 
     When access systems are installed in vehicles with OEM power sliding door systems, the access system must be configured such that operation of the ramp by the access system and operation of the door by the power sliding door system are coordinated to prevent interference between the door and the ramp. One method of preventing such interference is installing the access system in a manner that interrupts the door operation commands sent from the body control unit to the door control unit. This method requires the access system to be in communication with the data bus of the power sliding door system, either directly or through a gateway. While these methods have proven effective in the past, vehicle manufacturers are becoming less willing to allow installers of vehicle access systems to modify or otherwise communicate with or on the vehicle data bus. 
     SUMMARY 
     The invention may include a control system for providing wheelchair access to a vehicle that has a door and a ramp. The system includes a door actuator that is operable to move the door between an opened position and a closed position, and a ramp actuator that is operable to move the ramp between a stowed position and a deployed position. A door control unit is operable to control a supply of electrical power delivered to the door actuator in response to a door operation request. A power line coupled between the door control unit and the door actuator carries the supply of electrical power to the door actuator. An access controller is coupled to the ramp actuator and to the power line, and is operable to selectively prohibit the supply of electrical power from reaching the door actuator when the ramp is deployed. 
     The invention may also include a method for controlling a door operation system and a ramp system in a vehicle modified for handicapped access. The method includes selecting a vehicle with an OEM door operation system including a door control unit and a door actuator. The door control unit is operable to provide a supply of electrical power to the door actuator. An access controller is installed in the vehicle and coupled to the door operation system between the door control unit and the door actuator. The access controller is also coupled to the ramp system, which includes a ramp. When the ramp is in a deployed position, the supply of electrical power provided by the door control unit is prevented from reaching the door actuator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, the same reference symbols designate the same parts, components, modules or steps, unless and to the extent indicated otherwise. 
         FIG. 1  is a block diagram of a switch-based interface system as implemented between a power sliding door system and a ramp controller; and 
         FIG. 2  is a circuit diagram of a switch-based interface system. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an access system  10  that provides access to a vehicle. The access system  10  includes an access controller in the form of a switch-based door and ramp interface system  100  and a ramp control system  106  that are connected to and interface with various OEM vehicle components to coordinate operation of the door and the ramp. The interface system  100  is coupled to and cooperates with an OEM door control unit  104 , which is operable to open and close the door of the vehicle (not shown). To open and close the door, the door control unit  104  communicates and cooperates with other OEM components including a body control unit  102 , a remote receiver  120 , a remote transmitter  122  (generally in the form of a remote key fob), a communications bus  140  and various door switches, including sliding door satellite switch  101 . The door control unit  104  operates to provide electrical power to a motor and clutch controller  132  including a door motor  131 , and a door latch release actuator  108 . 
     The ramp control system  106  is coupled to the interface system  100  and is operable to deploy and stow the ramp (not shown). Unlike the door control unit  104 , body control unit  102  and other OEM components discussed above, the interface system  100 , the ramp control system  106 , and other components of the access system  10  are generally installed by a third party after the vehicle has been manufactured. Therefore, it is unlikely that the door control unit  104  includes a mechanism that will prevent operational interference between the door and the ramp. As a result, the interface system  100  is generally installed in the vehicle with the access system  10  to coordinate operation of the OEM door control unit  104  with the aftermarket ramp control system  106 . 
     One way in which the interface system  100  prevents operational interference between the ramp and the door is by interrupting electrical power communicated by the door control unit  104  to the door motor  131  when the ramp is not fully stowed. The interface system  100  is also coupled between the door control unit  104  and the latch release actuator  108 . The latch release actuator  108  unlatches the door from the frame of the vehicle so that the door is free to move. Once the door is unlatched, the motor and clutch controller  132  is then able to move the door. By interrupting electrical power to the latch release actuator  108  and the door motor  131 , interface system  100  may prevent movement of the door. Unlike some other systems, the interface system  100  does not communicate with the communications bus  140 , nor does it send or receive any control signals to or from the body control unit  104 . In some embodiments, the interface system  100  interrupts the power to the latch release actuator  108  and the motor and clutch controller  132  whenever the ramp is not fully stowed, as discussed further below. 
     As shown in  FIG. 2 , the interface system  100  is coupled to a battery  130  and includes a ramp trigger relay  230  including a ramp trigger coil  260  and a ramp trigger switch  262 , a door relay  232  including door coil  264  and a door relay switch  268 , a motor and clutch relay  234  including a motor and clutch coil  270  and a motor and clutch switch  272 , a ramp signal relay  236  including a first ramp signal coil  238 , a second ramp signal coil  242 , and a ramp signal switch  240  (which in the illustrated construction includes a pair of individual switches coupled for operation together), a door trigger relay  244  including a door trigger coil  245  and a door trigger switch  256 , and a door handle detection relay  248  including a first door handle detection coil  250 , a second door handle detection coil  252 , and a door handle detection switch  254 . Alternatively, the interface system  100  may include transistors. The door relay  232  is coupled between the door control unit  104  and the latch release actuator  108  by leads  12   a  and  12   b . The motor and clutch relay  234  is coupled between the door control unit  104  and the motor and clutch controller  132  by leads  13   a  and  13   b . The door switch  268  of the door relay  232  remains open until the door coil  264  is activated. Therefore, unless the coil is activated, when the door control unit  104  communicates a power signal, the power signal will be interrupted by the open door switch  268  of the door relay  232 . Similarly, the motor and clutch switch  272  of the motor and clutch relay  234  remains open until the motor and clutch coil  270  is activated. The door coil  264  and the motor and clutch coil  270  are activated when the ramp is stowed. When the ramp is no longer fully stowed, a ramp stowed switch  114  will open, thereby disconnecting the coils  264  and  270  from ground and causing the coils  264  and  270  to deactivate. When the coils  264  and  270  are deactivated, the switches  268  and  272 , respectively, open. Thus, the power to the latch release actuator  108  and motor and clutch controller  132  are interrupted. The ramp stowed switch  114  is also coupled to a ramp stowed input  137  of the ramp controller  106  so the ramp controller can determine whether or not the ramp is fully stowed. 
     The interface system  100  controls the power to the latch release actuator  108  and to the motor and clutch controller  132  as described above when the door operation request is communicated with the door control unit  104  by the body control unit  102  ( FIG. 1 ). Although the door control unit  104  contains software and hardware that controls the proper operation of the latch release actuator  108  and motor and clutch controller  132 , the door control unit  104  needs to receive authorization from the body control unit  102  before such operation. The door control unit  104  receives authorization from the body control unit  102  when certain conditions are met. For example, the body control unit  102  may monitor several switches mounted at various places inside the vehicle, which reflect conditions such as transmission position, vehicle speed, and door lock condition. If the body control unit  102  determines that the conditions are met, it then sends authorization to the door control unit  104 . 
     The body control unit  102  may receive a door operation request from a sliding door satellite switch  101 . This switch is tied to chassis ground and when depressed sends a ground (low) signal to the body control unit  102 . Alternately or additionally, the body control unit  102  may receive a door operation request from a remote transmitter  122  via a remote receiver  120  (which may be located inside the vehicle) and a second data bus  141 . The remote transmitter  122  may enable keyless entry into the vehicle by communicating a door operation request to the body control unit  102 . The remote transmitter  122  may include a button, be mounted on a keychain and may issue a door operation request when the button is pushed. 
     However, if the door operation request is communicated with the door control unit  104  without going through the body control unit  102  first, the interface system  100  may control the power from the door control unit  102  in a different manner. Such door operation requests may originate from a pillar switch (such as B pillar switch  220 , C pillar switch  222 ) an optional switch  224 , the vehicle&#39;s inside door handle  110  or the vehicle&#39;s outside vehicle door handle  112 . As shown in  FIGS. 1 and 2 , when a pillar switch  220 ,  222 , optional switch  224  or door handle switch  110 ,  112  is activated, it sends a ground (low) signal to the door control unit  104 , bypassing the body control unit  102 . 
     For example, upon receiving a door operation request from one of the pillar switches  220 ,  222 , or from the optional switch  224 , the door control unit  104  may send power to the latch release actuator  108  over lead  12   a  and to the ramp trigger relay  230 , which is also coupled to lead  12   a . Sending power over lead  12   a  activates the ramp trigger coil  260  of the ramp trigger relay  230  and causes the ramp trigger switch  262  to close. Closing of the ramp trigger switch  262  communicates a ground signal to the trigger input  142  of the ramp controller  106 , which activates the ramp controller  106 . 
     If the door is closed and the ramp is stowed upon receiving a door operation request from one of the pillar switches  220 ,  222 , or from the optional switch  224 , the ramp stowed switch  114  is closed, and therefore the door relay switch  268  and motor and clutch switch  272  are also closed. As a result, if the door control unit  104  sends power over lead  12   a  or lead  13   a , that power is communicated to the latch release actuator  108  or motor and clutch controller  132  to allow the door to open. 
     If the door is open and the ramp is deployed upon receiving a door operation request from one of the pillar switches  220 ,  222 , or from the optional switch  224 , the ground signal provided to the trigger input  142  of the ramp controller  106  causes the ramp to stow. Because the ramp is not initially stowed and the ramp stowed switch  114  is therefore open, the motor and clutch switch  272  is also open. Thus, any power sent by the door control unit  104  over lead  13   a  is not provided to the door motor  131 , thereby preventing closing the door on the deployed ramp. 
     The door close output  113  of the ramp controller  106  is configured to activate the door trigger coil  245  of the door trigger relay  244 . The door trigger relay  244 , when activated, sends a ground (low) signal over lead  14  that duplicates the ground signal provided to the door control unit  104  when one of the B pillar switches  220 ,  222  or the optional switch  224  is depressed. This ground signal is transmitted to the OEM door control unit  104  which interprets this signal as a request to operate the power slide door from the B Pillar switch  220 . The ramp controller  106  only activates the door trigger coil  245  to communicate this ground signal once it senses that the ramp is fully stowed, as indicated by detecting a ground signal at the ramp stowed input  137 . Because the ramp is fully stowed, the door relay  232  and the motor and clutch relay  234  are closed, thus allowing power to be provided to the door motor  131  to close the door. 
     The following will discuss operation of the interface system  100  when the outside door handle switch  112  is activated. When the outside door handle is activated by, for example, a user entering the vehicle who does not wish to use the ramp, the outside door handle switch  112  is closed, thus communicating a door operation request in the form of a ground signal to the door control unit  104  (see  FIG. 1 ). Under these conditions, the ramp interface system  100  may prevent the ramp from deploying and the vehicle from kneeling. The door handle detection relay  248  and the ramp signal relay  236  are configured to recognize this situation and to allow the door to open while preventing the ramp from deploying and the vehicle from kneeling. In general, if the door handle detection relay  248  and the ramp signal relay  236  detect that a door operation request has been sent to the door control unit  104  from either door handle switch  110  or  112 , the door handle detection relay  248  and the ramp signal relay  236  cooperate to send signals to the ramp controller  106  indicating that the ramp is already deployed and the vehicle is already kneeled. Because the ramp controller  106  detects that the ramp is deployed and the vehicle kneeled, the ramp controller  106  will not deploy the ramp. 
     If the door is closed when the outside door handle  112  is operated, the door will start to open. The ramp controller  106  includes a sensor that communicates a signal to the ramp controller  106  when the door is active, which prompts the ramp controller  106  to activate as well. However, the first door handle detection coil  250  of the door handle detection relay  248 , which is coupled to lead  12   a , is also activated. Activation of the first door handle detection coil causes the door handle detection switch to close, which in turn provides a ground signal (by way of the door handle switch) to activate the first ramp signal coil  238  of the ramp signal relay  236 . Activation of the first ramp signal coil  238  causes the ramp signal switch  240  to close, which communicates a ground signal to the ramp deployed input  134  and the kneel lowered input  136  of the ramp controller  106 . This ground signal mimics a ground signal that would otherwise be provided by a kneel lowered switch  210  or a ramp deployed switch  212 , which causes the ramp controller  106  to sense that the ramp is deployed and the vehicle is lowered (kneeled), even though they are not. Thus, when the door reaches the fully open position, the ramp controller  106  will not deploy the ramp. 
     While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.

Technology Classification (CPC): 4