Abstract:
By law, a stand-up lift truck operator must be trained to keep both feet and legs located within an operator compartment. An exemplary operator presence detector includes multiple zones, or areas, configured to receive an operator&#39;s feet. A sensor arrangement detects the presence of the operator&#39;s feet and a logic device determines whether the operator&#39;s feet are present in the zones or areas in a predetermined configuration, such as a configuration that reinforces operator training to keep both feet in a designated area on a compartment platform. In preferred arrangements, based on whether the operator&#39;s feet are present in the zones in a predetermined configuration, at least one vehicle function is enabled or disabled which may serve to reinforce an operator&#39;s training to keep both feet and legs located within an operator&#39;s compartment.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 61/666,448 titled “Vehicle Operator Presence Detector,” filed on 29 Jun. 2012. 
     
    
     TECHNICAL FIELD 
       [0002]    The disclosure pertains to detecting a vehicle operator&#39;s presence and enabling or not enabling one or more vehicle functions based on such detection, for example, to reinforce operator training. 
       BACKGROUND 
       [0003]    Operators stand when driving industrial vehicles, such as end-rider lift trucks, reach trucks, straddle trucks, docker trucks, order picker trucks and motorized pallet trucks. By federal law, the operators of such industrial vehicles are required to have rigorous training, certification and recertification by their employers. Such training includes instruction that the operator maintain both feet and legs within the operator&#39;s compartment during use. Various systems and methods have been developed to reinforce such operator training while an industrial vehicle is in use. 
       SUMMARY 
       [0004]    Disclosed systems and methods detect when an operator is or is not standing properly in an operator&#39;s compartment, preferably in a manner consistent with the driver&#39;s training. In preferred embodiments, the entire vehicle, or one or more functions of the vehicle, may be enabled or disabled depending on whether an operator&#39;s position on a driving platform is consistent with the training received by the operator. For example, a drive function of an end-rider lift truck may be disabled when a detection device or system associated with such a vehicle detects there is no operator on the drive platform or a driver on the drive platform is not standing with both feet in a predetermined configuration; or multiple functions may be disabled, such as a drive function and a hoist function. 
         [0005]    According to one embodiment, an operator presence detector includes multiple zones, or areas, configured to receive an operator&#39;s feet. A sensor arrangement detects the presence of the operator&#39;s feet and a logic device determines whether the operator&#39;s feet are present in the zones or areas in a predetermined configuration, such as a configuration that reinforces operator training to keep both feet in an operator&#39;s compartment. Based on whether the operator&#39;s feet are detected in the zones in a predetermined configuration, at least one vehicle function is enabled or disabled which may serve to reinforce an operator&#39;s training. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIGS. 1 and 1A  are diagrams of prior art operator presence detectors. 
           [0007]      FIG. 2  is a diagram of an embodiment of an operator presence detector in an end-rider lift truck. 
           [0008]      FIG. 3  is an enlarged view of the operator presence detector of  FIG. 2 . 
           [0009]      FIG. 4  is an enlarged view of an alternate operator presence detector. 
           [0010]      FIG. 4A  is an enlarged view of an alternate operator presence detector. 
           [0011]      FIG. 5  is a schematic diagram of an operator presence detector installation. 
           [0012]      FIG. 6  is a diagram of an exemplary dataset used by a logic device. 
           [0013]      FIG. 7  is a schematic diagram of another operator presence detector embodiment. 
           [0014]      FIG. 8  is a schematic diagram of another operator presence detector embodiment. 
           [0015]      FIG. 9  is a flowchart of an exemplary method for operating an operator presence detector. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    The present inventors have recognized disadvantages associated with commonly available operator presence detectors associated with driving platforms for vehicles. One such disadvantage is that some operator presence detectors may be activated by a single foot, thus not reinforcing operator training by enabling an operator to operate a vehicle and all of its functions with only one foot on a driving platform. For an example, see U.S. Pat. No. 8,141,886 at column 12, line 13 through column 13, line 21 and FIGS. 8 and 9 therein. Another such disadvantage is that some operator presence detectors include two specific places, typically having a switch located at each place, where an operator must place each foot, thus providing only a limited ability for an operator to shift foot placement which may lead to fatigue or discomfort for the operator while driving the vehicle. An example of such a prior art detector is illustrated in  FIG. 1  which requires an operator to have one foot on switch  10  and the other foot on switch  15  to drive truck  20 . Another example illustrated in  FIG. 1A  is the iScrub Chariot  9  manufactured by Windsor of Englewood, Colorado. The iScrub Chariot  9  includes a throttle  4  and an operator presence pedal  5  separated by a protruding fin  6 . Described embodiments may overcome such disadvantages, or may address other needs. 
         [0017]      FIG. 2  illustrates a vehicle, such as end-rider lift truck  25 , having a driving platform  30  associated with an example operator presence detector  35 . When driving the end-rider lift truck  25 , an operator&#39;s back may rest against backrest  40  and both feet are placed on the driving platform  30 , preferably without either foot extending beyond an outer edge  45  of the driving platform  30 . 
         [0018]    The example operator presence detector  35  includes a sensor arrangement comprising a pressure sensitive mat  50  ( FIG. 3 ) configured with four zones  55 ,  60 ,  65  and  70  as best illustrated in  FIG. 3 . Each zone  55 ,  60 ,  65  and  70  is configured to receive at least a portion of an operator&#39;s foot. In the embodiment illustrated in  FIGS. 2 and 3 , each zone  55 ,  60 ,  65  and  70  is large enough for an operator to place the entirety of a foot in any of the zones  55 ,  60 ,  65  and  70  while leaving surface area of a zone  55 ,  60 ,  65  or  70  uncovered by such a received foot. In other embodiments, a zone may be configured to receive an operator&#39;s foot by being sized and constructed such that only a portion of an operator&#39;s foot fits into or on the zone or such that an operator&#39;s foot completely covers the zone. A zone receiving an operator&#39;s foot therefore includes an operator placing at least a portion of a foot into or on a zone as well as an operator placing an entire foot into or on a zone. 
         [0019]    The operator presence detector  35  is configured to detect an operator&#39;s foot in any of zones  55 ,  60 ,  65  and  70 . For example, when an operator&#39;s foot is received in one of the zones  55 ,  60 ,  65  or  70  and such foot applies a minimum load in the range of approximately 10 kilograms (Kg) disk of diameter 80 millimeters (mm) to approximately 20 kilograms (Kg) disk of diameter 80 millimeters (mm), and preferably in the range of approximately 12 kilograms (Kg) disk of diameter 80 millimeters (mm) to approximately 18 kilograms (Kg) disk of diameter 80 millimeters (mm), the portion of the pressure sensitive mat  50  comprising the zone, or zones, where the foot is placed generates a foot-present signal, such as an analog or digital electrical signal, an optical signal or other suitable signal, that is transmitted to a logic device, for example, via a cable, such as cable  75 A ( FIG. 4 ), or wirelessly. Thus, when an operator&#39;s foot is placed in zone  55  and sufficient force is applied to the underlying pressure sensitive mat  50 , a foot-present signal corresponding to zone  55  is transmitted to a logic device and likewise for each of zones  60 ,  65  and  70 . 
         [0020]    Cable  75 A is connected to a logic device, such as digital processor  80  ( FIG. 5 ) that receives the foot-present signals generated by the operator presence detector  35 A. The digital processor  80  is programmed to determine in which of zones  55 A,  60 A,  65 A and  70 A the operator&#39;s feet are present based on the foot-present signals. Such programming may be accomplished via software operating with the digital processor  80 , hardware that is formed as part of the digital processor  80  or other suitable manner. 
         [0021]    The digital processor  80  is further programmed to determine whether the operator&#39;s feet are in the zones  55 ,  60 ,  65  and  70  in a predetermined configuration. In one embodiment, the digital processor&#39;s programming compares the zones where a foot is determined to be present against a dataset of predetermined configurations with an enable designation. An example dataset of such predetermined configurations is illustrated in  FIG. 6 . The dataset illustrated in  FIG. 6  applies to an operator presence detector with  4  zones, such as operator presence detector  35 , and includes  11  unique combinations,  7  of which carry an enable designation and  4  of which carry a disable designation. If a foot-present signal comes from only one, or none, of the zones  55 ,  60 ,  65 , or  70  a disabled designation applies. For the four zone operator presence detector  35 , the example dataset illustrated in  FIG. 6  provides an almost unlimited variety of operator foot placement positions that will enable one or more vehicle functions. As discussed below, providing numerous foot placement positions for an operator preferably permits an operator to shift foot placements without interrupting one or more vehicle functions. Based on the number of zones, the variety of operator foot placements desired, the desired locations for an operator&#39;s feet, for example, to reinforce operator training, or other suitable factors, singularly or in any combination, a dataset may be constructed to designate the combination of zones that must detect a foot to enable one or more vehicle functions, or to disable one or more vehicle functions, singularly or in any combination. 
         [0022]    The digital processor  80  is further programmed to transmit, or send, an enable, or a disable, signal to the vehicle  25 , for example, to a system that performs a vehicle function, such as a drive, or traction, system (not illustrated) in response to determining that an operator&#39;s feet are present in the zones  55 ,  60 ,  65  and  70  in a predetermined configuration. Such transmission by the digital processor  80  may be directly to a vehicle system, or may be indirect, that is, via another processor or vehicle system. 
         [0023]    Preferably, one or more vehicle functions, such as activating a drive system, hoist system or other suitable system are disabled unless an enable signal is transmitted by digital processor  80 . In certain embodiments, the digital processor  80  transmits or sends a disable signal, for example, when no operator is detected by the operator presence detector or the operator&#39;s feet are not present in the zones of an operator presence detector in a predetermined configuration, thus not enabling or disabling one or more vehicle functions. 
         [0024]    Optionally, a signal delay device may be included. A signal delay device preferably continues to provide a foot-present signal to the logic device for a predetermined amount of time or provides a timing count that must elapse before the logic device stops sending an enable signal in response to an operator removing a foot from a zone or zones. For example, an operator driving end-rider lift truck  25  initially starts driving with one foot in zone  55  and the other foot in zone  65 . While driving, the operator may shift foot placement, for example, to ease discomfort or because the operator is becoming fatigued, and thus moves the foot present in zone  55  to span zones  55  and  60  and the foot present in zone  65  to zone  70 . 
         [0025]    Instead of disabling the drive function (or other suitable function or functions) of the end-rider lift truck  25  in response to the interruption in foot-present signals from the operator presence detector  35  because of the operator&#39;s foot shifting, a signal delay device, such as clock  85 , is used to measure, or time, a predetermined amount of time, such as 0.10 to 0.30 second and preferably 0.15 to 0.25 second that must elapse before the processor  80  stops transmitting an enable signal to the end-rider lift truck  25 . During the predetermined amount of time, new foot-present signals corresponding to zones  55 ,  60  and  70  are sent to the processor  80 . Based on the foot-present signals corresponding to zones  55 ,  60  and  70 , the processor  80  determines that the operator&#39;s feet are present in zones in a predetermined configuration (using the dataset illustrated in  FIG. 6 ) and sends an enable signal to the end-rider lift truck  25 . Thus, an operator may shift foot locations from one predetermined zone configuration to another predetermined zone configuration without disabling a vehicle function because of such shifting. 
         [0026]    Although optional, the embodiment illustrated in  FIGS. 2 and 3  includes a physical barrier, such as disc  90 . Disc  90  is arranged, that is, appropriately sized and located, to hinder an operator from placing one foot in a position where the sensor arrangement, such as pressure sensitive mat  50 , detects the presence of the one foot in more than one of zones  55 ,  60 ,  65  and  70  such that a vehicle function would be enabled by the one foot. For example, the top of disc  90  may be approximately 25 mm above the surface of the operator presence detector  35 , be approximately 75 mm in diameter and be located at the intersection of zones  55 ,  60 ,  65  and  70 . For the example dataset of preconfigured zones illustrated in  FIG. 6 , the disc  90  hinders an operator from applying sufficient force with one foot to cause the pressure sensitive mat  50  to detect the presence of the one foot in both of zones  55  and  65  or in both of zones  60  and  70  and thus enable one or more vehicle functions with only one foot. 
         [0027]    Optionally, a shut-off zone, such as zone  90 B ( FIG. 4A ), may be included between the other zones  55 B,  60 B,  65 B, and  70 B to hinder an operator from enabling one or more vehicle functions by activating two or more of zones  55 B,  60 B,  65 B, and  70 B in a predetermined manner with one foot. For example, zone  90 B may be used instead of a physical barrier. A logic device may be programmed to disable a vehicle function, such as traction, or to apply a vehicle function, such as braking, when a foot-present signal is received from zone  90 B, even if foot present-signals are received from a combination of zones  55 B,  60 B,  65 B, and  70 B in a predetermined zone configuration. 
         [0028]    Optionally, other embodiments may locate the zones with respect to each other in a physical arrangement that hinders an operator from placing one foot in a position where the sensor arrangement detects the presence of the one foot in more than one zone such that a vehicle function would be enabled by the one foot. For example, zone  55 C ( FIG. 7 ) may be spaced approximately 50 mm from zone  65 C and zone  60 C may be spaced approximately 50 mm from zone  70 C. Other embodiments may combine one or more of a physical barrier, shut-off zones, and locating the zones with respect to each other such that the location of the zones, the location of the shut-off zones and/or the physical barrier cooperate to hinder an operator from placing one foot in a position where the sensor arrangement detects the presence of the one foot in more than one zone such that a vehicle function would be enabled by the one foot. 
         [0029]    While a preferred zone layout, sensor arrangement, logic device and physical barrier have been described, the invention is not so limited. Four zones were described, however the number of zones may be 2 or more, preferably between 3 and 6. The number, location, size and shape of the zones will vary according to numerous factors including the vehicle layout and where it is desirable for an operator&#39;s feet to be placed. 
         [0030]    Suitable sensor arrangements include pressure sensitive or weight activated switches with one or more such switches underlying each zone, optical sensors (such as light beam interruption detectors or imagers coupled with object recognition software), thermal sensors and other devices suitable for identifying the location of an operator&#39;s feet with respect to the zones of an operator presence detector. 
         [0031]    Suitable logic devices include analog devices such as relays, application-specific integrated circuits, microprocessors and other devices suitable for receiving foot-presence signals and determining in which zones an operator&#39;s feet are present based on such foot-present signals. Note that a dataset is not required for use with all logic devices. For example, an analog logic device may make its determinations regarding in which zones a foot is present based on a combination of input signals, such as specific lines or channels carrying a signal. A logic device may thus be programmed via the physical construction of the logic device, computer programming, or other suitable manner. 
         [0032]    Other suitable physical barriers include rigid structures located within an operator presence detector and between at least some of the zones, rigid structures located at or above the surface of an operator presence detector and between at least some of the zones and other structures suitable for hindering placement of a foot in a location where the foot is detected by a sensor arrangement and subsequently determined to be present in more than one zone such that a vehicle function would be enabled by the one foot. 
         [0033]    The embodiment illustrated in  FIG. 8  has a similar configuration and operation to the embodiment illustrated in  FIGS. 2 ,  3 , and  4 , but includes two optional, exemplary shut-off zones  90 D and  95 . A dataset used by a logic device, such as processor  80  ( FIG. 5 ), may be similar to that illustrated in  FIG. 6 , but may include additional entries. For example, additional entries include whether a foot is present in either the shut-off zone  95  or the shut-off zone  90 D or not. If a foot is detected in either of the shut-off zones  90 D or  95  the processor  80  does not transmit or send an enable signal based on receiving a foot-present signal from either of the shut-off zones  90 D or  95 , even if the operator&#39;s feet are otherwise placed such that the feet are detected in zones  55 D,  60 D,  65 D, and  70 D in a predetermined configuration, for this example, corresponding to a dataset entry carrying an “enable” designation. In certain embodiments, either of the shut-off zones  90 D or  95  may create and transmit a shut-off signal to the logic device, such as processor  80 , that tells the logic device not to transmit an enable signal. 
         [0034]      FIG. 9  illustrates an example method for operating an operator presence detector, such as operator presence detector  35 . At  100 , an operator steps onto a drive platform and a sensor arrangement detects the presence of the operator&#39;s feet received by zones of the operator presence detector at  105 . At  110 , foot-present signals corresponding to the zones where a foot is detected are generated and transmitted to a logic device. Based on the foot-present signals, the logic device determines whether the operator&#39;s feet are present in the zones in a predetermined configuration at  115 . 
         [0035]    If the operator&#39;s feet are not present in the zones in a predetermined configuration at least a selected vehicle function is or remains disabled, or the logic device generates and transmits a disable signal, at  120 . If the operator&#39;s feet are present in the zones in a predetermined configuration, the logic device generates and transmits an enable signal at  125  to enable at least a vehicle function. 
         [0036]    In some embodiments that include one or more shut-off zones, the logic device may determine whether a signal is received from at least one of the shut-off zones after step  115 , but before step  125 . If no signal is received from a shut-off zone, processing continues to step  125 . Otherwise, if a signal is received from a shut-off zone, processing continues to step  120 . 
         [0037]    At  130  the sensor arrangement detects whether the operator shifted the position of one foot or of both feet. If not, at  135  the logic device maintains the current enabled or disabled status for the at least one vehicle function. If so, at  140  a signal delay device causes the logic device to maintain the current enabled or disabled status for the at least one vehicle function for a predetermined time period while processing returns to  105 . 
         [0038]    It will be apparent to those skilled in the art that various modifications and variations can be made to the systems and methods of the present disclosure. Other embodiments of the methods and systems will be apparent to those skilled in the art from consideration of the specification and practice of the methods and systems disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the invention being indicated by the claims and their equivalents.