Abstract:
A vehicle information system has a first load sensor for generating a first load signal based on a first vehicle load. A first position sensor generates a first position signal based on a position of a vehicle axle. A second position sensor generates a second position signal based on a position of a vehicle kingpin. A memory unit stores vehicle optimization data. An evaluation unit is in communication with the first load sensor, the first position sensor, the second position sensor and the memory unit. A general user interface for receiving input is also in communication with the evaluation unit. The evaluation unit makes an evaluation of the first load signal, the first position sensor, the second position signal, and any input and generates a vehicle optimization instruction relating to a distance between the axle and the kingpin.

Description:
This patent application is a continuation-in-part and claims priority to U.S. Nonprovisional Patent Application No. 09/724,373 filed on Nov. 28, 2000, now abandoned. 

   BACKGROUND OF THE INVENTION 
   This invention relates to a system for determining and optimizing load distribution on a vehicle. 
   The distribution of load over a trailer significantly alters its handling, performance, and fuel efficiency. Braking, acceleration, turning, as well as operational safety of the vehicle are all affected by load distribution. Improper loading of a trailer not only reduces vehicle performance but also increases the risk of an accident. 
   Additionally, state and federal laws impose load limits on tractor/trailer combinations. Limits exist on maximum weight, weight over an axle, and weight over a tandem axle. These limits vary from state to state, requiring a driver to know whether he is in compliance with these limits as he crosses each state line. In the event a load exceeds these limits, the driver must either reduce or redistribute the load over the trailer to conform to regulatory requirements. Failure to comply with such limits can lead to the imposition of fines or other penalties. 
   Currently, load distribution is determined by employing rudimentary methods such as weighing the vehicle on a load scale. Typically, a tractor/trailer is driven onto a platform with load cells. These load cells send out electronic signals to junction boxes, which then sum all of the signals into one signal so that the signal can be read by a load indicator. The load of each axle can be determined either by derivation from the whole weight of the tractor/trailer or by weighing each axle individually. 
   On board systems for weighing load also exist. One such system measures the load directly by reading load cells on a bed. Another system measures load indirectly by relating load to air pressure on a suspension. Such systems provide the driver with a reading of load distribution only. They do not provide information on how load should be distributed. 
   While these foregoing methods provide basic information about the distribution of weight over a tractor/trailer, they do not provide information on how to optimize the distribution of weight to comply with load limits or to enhance vehicle performance. To determine compliance with load limits, a driver must manually compare load distribution values with state and federal weight limit tables. Because these limits vary from jurisdiction to jurisdiction as well as by tractor/trailer type and characteristics, for the hauling of particularly heavy loads, a driver must maintain updated tables for each jurisdiction and compare these tables with his load distribution for each state of operation. 
   Moreover, the measurements offered by these foregoing methods of determining load distribution are not integrated or analyzed with other vehicle characteristics that affect vehicle maneuverability and handling, such as tire pressure, axle position, or trailer height. Load distribution is accordingly not optimized for performance. 
   A trailer may have a slider, which permits the driver to adjust the location of the rear axles of the trailer relative to the front axle. When unloading, the slider is typically positioned closest to the rear of the trailer. Also, when there is little or no load in the trailer, the slider is usually moved to the position closest to the front of the trailer. However, the repositioning of the slider in these instances may result in a less than optimal slider position for other operational situations. 
   A need therefore exists for a system to provide information to optimize the distribution of load, including optimizing slider position, not only to comply with state and federal law but also to optimize vehicle performance. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a system for optimizing load distribution on a tractor/trailer or other vehicle. A computer or other evaluation unit reads the information from at least one load sensor, measuring the load and its distribution. The computer then evaluates the information with a database compiling information on optimizing load distribution for vehicle performance as well as for compliance with state and federal law. 
   The invention comprises a vehicle information system that optimizes vehicle performance and load distribution. A first position sensor generates a first position signal based on an actual location of a first vehicle component, say a trailer axle or slider. A load sensor generates a first load signal based on a first vehicle load. The evaluation unit of the vehicle information system communicates with both sensors and evaluates signals from these sensors. Based on these signals, the evaluation unit provides data on how to relocate the tractor axle for optimal vehicle performance and load distribution. 
   The vehicle information system may provide its instruction to a vehicle driver based on a determination of the vehicle&#39;s center of gravity as calculated from data from the first position sensor and the first load sensor. The vehicle information system may also employ a second load sensor that reads the load over a second vehicle component, such as a vehicle kingpin. A second position sensor may sense the location of the vehicle kingpin and communicate this information to the evaluation unit. The information system may also provide instruction for moving load within the vehicle to redistribute the center of gravity of the vehicle. 
   The evaluation unit may further receive information from a general user interface, such as an onboard computer interface, that receives input from the vehicle driver. A memory unit storing vehicle optimization data may also provide information that assists the evaluation unit in optimizing vehicle performance and load distribution. The vehicle optimization data may include information relating to federal and state load limits, such as bridge load limit laws. 
   The inventive information system senses the actual location of the tractor axle. A load distribution is determined electronically across the vehicle. The evaluation unit then determines an alternative location for the axle based on the sensed actual location of the axle and the load distribution across the vehicle. An alternative location of the axle is then displayed on a general user interface. Based on this information, a vehicle driver may adjust the location of the axle (by moving a slider) or adjust the load distribution. 
   A particular version of the invention may encompass a load sensor and two position sensors. One position sensor detects a location of a vehicle axle while the other position sensor determines the location of a vehicle kingpin. An evaluation unit receives information from the sensors as well as from a memory unit storing vehicle optimization data and a general user interface that receives input from the vehicle driver. Based on the information received from these sources, the evaluation unit may generate a vehicle optimization instruction relating to the optimal distance between the vehicle axle and the kingpin. The vehicle driver may then adjust the axle to this optimal distance. 
   In this way, the inventive information system provides a vehicle driver with the opportunity not only to determine his current load distribution but to adjust components of the vehicle as well as load within the vehicle to optimize the vehicle for performance as well as to comply with state and federal load limit requirements. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows: 
       FIG. 1  shows a top view of a tractor/trailer employing an embodiment of the invention, including evaluation unit and load sensors. 
       FIG. 2  shows a schematic of information provided to the evaluation unit. 
       FIG. 3  shows a side view of an embodiment of the invention. 
       FIG. 4  illustrates a vehicle component, here a slider. 
       FIG. 5  illustrates optimal load distribution for a vehicle. 
       FIG. 6  illustrates the adjustment of load distribution based on information provided by the inventive vehicle information system. 
       FIG. 7  illustrates the adjustment of the vehicle component based on information provided by the inventive vehicle information system. 
       FIG. 8  illustrates a flow chart of the inventive method. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  presents an embodiment of the invention. As known in the prior art, systems exist that measure the distribution of load across a vehicle such as tractor/trailer  20 , as seen in  FIG. 1 . These systems employ at least one or a plurality of load sensors  24 A–J to determine the load over axles  28 A–E as well as kingpin  32 , the mechanical pivoting pin link between the tractor and trailer. Such sensors may include load cells, piezo electric film sensors, or strain gauges. Pressure sensors measuring load on a vehicle&#39;s air suspension can also function as load sensors. Readings from load sensors  24 A–b J are then used to determine load distribution across tractor  38  and trailer  40 . 
   While readings from load sensors  24 A–J provide basic information concerning load distribution, such as weight over axles  28 A–E or even total weight of tractor/trailer  20 , a tractor/trailer driver must determine for himself whether his load is in compliance with state and federal law load limits or whether his load is distributed in a manner that minimizes the load&#39;s effect on vehicle performance and safety. A driver driving across numerous jurisdictions must maintain updated regulations and check compliance for each state entered. Additionally, in the event of the addition or redistribution of load, the driver must not only determine whether the load is in compliance with load limits but must attempt himself to configure his load to optimize vehicle performance. Current systems fail to perform these functions for the tractor/trailer driver. 
   In the present invention, evaluation unit  36  automatically provides the driver with a determination of how load distribution could be optimized for compliance with state and federal limits as well as for performance and operational safety of the vehicle. Evaluation unit  36  communicates with load sensors  24 A–J and evaluates the signal or information from these sensors with load optimization data stored in a memory unit within evaluation unit  36 . Evaluation unit  36  determines tractor axle loads from load sensors  24 A and  24 F (axle  28 A),  24 B and  24 G (axle  28 B), and  24 C and  24 H (axle  28 C), and trailer axle loads from load sensors  24 D and  24 I (axle  28 D) and  24 E and  24 J (axle  28 E). Additionally, loading at the tractor/trailer&#39;s kingpin  52  is determined and analyzed. 
     FIG. 2  illustrates types of load optimization data to be evaluated by evaluation unit  36 . Static vehicle characteristic information such as tractor and trailer length, the empty weight of the vehicle, ride height (nominal height of suspension measured from axle to frame), and vehicle load capacity are stored and processed with information from load sensors  24 A–J to optimize load distribution. Information from tractor/trailer  20 &#39;s power train such as engine and transmission data may also be stored in memory unit within evaluation unit  36  for optimizing vehicle performance and handling. 
   Dynamic features of tractor/trailer  20  are also monitored and evaluated. Trailer ride height, and kingpin to axle distances are a few of the dynamic inputs that are examined. A person skilled in the art would know a number of other dynamic as well as static features that may be used to monitor and evaluate load distribution. 
   As seen in  FIG. 3 , commercially available position sensors measure distances between components of tractor/trailer  20 . Position sensors  44 A–E and  48  measure axle  28 A, B, C, D, E to kingpin distances, for example the distance between  44 A (axle) and  48  (kingpin). Position sensors may also monitor the position of suspension member  50  and the distance between the axle and a frame. These distances are adjustable by tractor/trailers, and factor importantly in determining optimal load distribution on tractor  38  and trailer  40 . Evaluation unit  36  monitors all of these distances. 
   Once evaluation unit  36  assesses the foregoing dynamic and static features, evaluation unit  36  then evaluates this data with load limit information and performance information stored in memory unit of evaluation unit  36 . Load limit information comprises a database of compiled state and federal load regulations. Vehicle performance information comprises a database of instructions to improve vehicle handling and maneuvering based on load distribution. From a comparison of this information, evaluation unit  36  arrives at the optimal load distribution to comply with load limits or to enhance vehicle performance and safety. 
   Referring to  FIG. 3 , display  52  provides instruction to the operator to optimize load distribution. Display  52  may be a general user interface  56  to allow driver to query or respond to queries of evaluation unit  36 . The algorithms to perform these calculations are well within the skill of the worker in the art. Display  52 , general user interface  56 , and evaluation unit  36  can all be integrated into the cab of the tractor  36 , or remote, or even hand-held. 
   The invention allows the driver to readily optimize his vehicle for performance and compliance with load limits. For example, a driver loads at a loading dock wit a slider in the farthest rearward position. After loading, the driver examines display  52  and queries evaluation unit  36  to optimize the tractor/trailer  20  for city driving. Evaluation unit  36  reads signals from load sensors  24 A– 24 J and position sensors  44 A–E,  48 , and  50 . After reading and evaluating these sensors with load optimization data, display  52  then provides the driver with the optimal position of the slider for the given load distribution for city driving. Display  52  also warns the driver of any axle overload conditions or state and federal load limit violations. After each delivery of load, the driver can continue to query evaluation unit  36  to configure the tractor/trailer  20  for optimal performance by repositioning load and/or repositioning components. 
   The invention allows drivers to avoid load limit violations and improve vehicle performance for any given load. The system electronically performs this function by evaluating load distribution with a database of vehicle performance information and a database of state and federal regulations. This system replaces the manual process of checking load distribution against tables of load limits as well as the tractor/trailer driver&#39;s best estimate on optimizing the vehicle for performance. Improved vehicle handling and safety, cargo efficiency and better tire and brake wear will result. 
   One particular version of the invention provides information to a vehicle driver on how to adjust a vehicle component of tractor/trailer  20 , such as slider  50  so as to maximize performance and improve load distribution.  FIG. 4  illustrates a close up view of slider  50 . As known, a trailer slider carries two tandem axles, axle  28 D and axle  2 SE, mounted to carriage  51 . Carriage  51  has pins  66  that fit within holes  62  of rails  53 , which are attached to trailer  40 . Holes  62  are typically spaced about six inches apart. By removing pins  66  from hole  62 , carriage  51  and tandem axles  28 D and  28 E may be moved along axis X relative to trailer  40  to permit the position of axle  28 D and  28 E to change. The slider is shown schematically here, as it is simply as known in the art. Slider  150  typically allows an adjustment of about 100 inches from L min  to L max  of carriage  51 . 
   Typically, a driver must guess as to the best position for axles  28 D and  28 E for given load. However, evaluation unit  36  provides the optimal position for slider  50  so that a driver may receive this information from display  52  and adjust axle  28 D and  28 E accordingly. In this way, evaluation unit  36  enhances vehicle performance and load distribution. 
   Specifically, referring to  FIGS. 5–8 , the inventive system and method will now be explained.  FIG. 5  shows tractor/trailer  20  having a particular load distribution. As shown, tractor  38  has weight W t  exerting a downward force  t  across axle  28 A. Additionally, trailer  40  has center of gravity C G  with weight W as indicated. Opposing W t  and W are equal and opposite forces from the ground, force T, force F, and force R. 
   Force T represents force through axle  28 A. Force F represents force through kingpin  32  while Force R represents force through point O, have the center location between axle  28 D and axle  28 E. As shown in  FIG. 1 , the value for W t  may be determined from load sensors  24 A and  24 F. The value for T is simply the opposite value. In addition, the value for F is determined from load sensors  24 B, C, G and H, while the value for R is determined from load sensors  24 D, E, I and J. 
   Referring to  FIG. 5 , distance L is the distance between Force F, kingpin  32 , and Point O. Distance a represents the distance between Force F and Center of Gravity, C G , and Distance b represents the distance between Point O and Center of Gravity, C G . Distance L may be determined from position sensors  44 B and  44 C and  44 D and  44 E. 
   Because trailer  40  is vertically static, the sum of moments about point O result in the following equation:
 
Wb=FL
 
 F=Wb/L  
 
Note, W t  and T are ignored because their effect on the analysis is negligible. If these values were not negligible, then they may be factored into the analysis. It is also known that the best load distribution across axles  28 B,  28 C,  28 D and  28 E arises when F=R and a=b or b=L/2. Therefore, it is optimal to locate C G  such that a=b.  FIG. 5  shows this optimal location of Center of Gravity, C G , with first load  66  and second load  70 .
 
   As shown in  FIG. 6 , trailer  40  may have load distribution that places center of gravity C G  of trailer  40  where distance a does not equal distance b. For example, first load  66  and second load  70  may be distributed across vehicle trailer  40  such that distance a is greater than distance b. In this instance, vehicle performance is not optimized for the particular load distribution because a is greater than b, i.e., the center of gravity C G  is located too close to point O. For this particular situation, evaluation unit  36  will determine the location of C G  and distances a and b. Evaluation unit  36  may then instruct vehicle driver through display  52  to move first load  66  to point P to thereby alter C G  so that distance a equals distance B. 
   Alternatively, as shown in  FIG. 7 , evaluation unit  36  may instruct vehicle driver through display  52  to reposition carriage  51  so that distance L is lengthened allowing distance a to equal distance b. Both of these adjustments are determined from reading data from load sensors and position sensors of vehicle  20 .  FIG. 8  illustrates how evaluation unit  36  may make this determination. 
   As shown in  FIG. 8 , initially a driver may input certain data into evaluation unit  36  through general user interface  56  to inform evaluation unit  36  of certain vehicle characteristics. For example, the driver may input the maximum and minimum distance L that can be achieved by moving carriage  51 . In addition, as shown in  FIG. 4 , carriage  51  is moved from hole to hole in increments, such as six inch increments, due to the spacing of holes  62 . These increments may also be inputted into evaluation  36  by vehicle driver. This information may also be preloaded into evaluation  36  by the manufacturer. 
   Following input of the foregoing information, as shown in  FIG. 8 , evaluation unit  36  gathers data from load sensors  24 B,  24 C,  24 G,  24 H and load sensors  24 D,  24 E,  24 I and  24 J to determine W, F and R, as well as from position sensors  44 B and  44 C and position sensors  44 D and  44 E to determine L. From this information, evaluation unit  36  determines the location of center of gravity C G  as well as distances a and b. 
   Evaluation unit  36  then retrieves vehicle optimization data, such as load limit information from memory unit within evaluation unit  36 . Vehicle optimization data may comprise load limit information, such as state and/or federal bridge load limit laws. Evaluation unit  36  determines whether trailer  40  complies with these laws. If trailer  40  does not, evaluation unit  36  outputs an instruction to a vehicle driver through display  52  to reduce vehicle load. Following this action by vehicle driver, evaluation unit  30  again reads load sensors and position sensors to determine center of gravity C G  location as well as distance a and distance b. When trailer  40  complies with load limit regulations, then evaluation unit  36  determines whether distance a is greater than b. Because carriage  51  moves in increments, evaluation unit  36  may take these increments into account as an error tolerance. For example, the spacing between holes  62  is six inches, then evaluation unit  36  determines whether distance a is greater than b give or take six inches. If so, evaluation unit  36  calculates a temporary value for L in which load distribution would be optimized for vehicle performance. This temporary value for L is then compared with the allowable value for distance L, L max . If the temporary value of L is greater than L max , then evaluation unit  36  determines that temporary value L cannot be implemented and outputs through display  52  an instruction to the vehicle driver to move cargo forward towards tractor  38  so that the center of gravity C g  for trailer  40  may be adjusted. Evaluation unit  36  then determines the new center of gravity C G  location as well as related distances a and distance b and begins the analysis again until temporary value L is not greater than L max . Then, evaluation unit  36  outputs temporary value L as the suggested location for carriage  51 . Carriage  51  is then moved into position to make temporary value L the distance between carriage  51  and kingpin  32 . 
   Alternatively, if evaluation unit  36  determines that a is less than b, then evaluation unit  36  decreases L and determines whether this temporary value is less than L min . If so, then evaluation unit  36  outputs an instruction to display  52  to the vehicle driver to move cargo toward the rear of trailer  40 . Evaluation unit  36  then obtains new data from load sensors and position sensors and once again determines the center of gravity C G  location as well as distance a and b. When the suggested L is allowed, then this suggested L is outputted on display  52  to allow a vehicle driver to adjust first vehicle component  74  accordingly. 
   Finally, if a=b within the error of tolerance, then evaluation unit indicates that first vehicle component is at its optimal location. No further adjustment is necessary. Evaluation unit  36  instructs vehicle driver that carriage  51  is at optimal position through display  52 . In this way, the inventive system and method provides a vehicle driver with the opportunity to reposition load and the truck slide to optimize the truck for vehicle performance and compliance with state and federal laws. 
   The aforementioned description is exemplary rather that limiting. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed. However, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. Hence, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For this reason the following claims should be studied to determine the true scope and content of this invention.