HK1179592B - Elevator dispatch control to avoid passenger confusion - Google Patents

Description

Elevator dispatch control to avoid passenger confusion

Background

Elevator systems are widely used, for example, to carry passengers between various floors in a building. For many years, elevators operate based on hall calls that are activated by a passenger pressing a hall call button indicating a desire to go up or down from a particular floor. Many such elevator systems include hall lanterns that indicate the direction of movement of an elevator car to reach a particular landing. Hall lanterns allow passengers to determine whether they are to board a particular car based in part on whether the car is facing the direction in which the passenger is to travel.

Modern elevator systems may include a variety of different technologies to allow passengers to place calls for elevator service. For example, destination entry systems allow passengers to provide an indication of the destination floor to which they are going before they enter an elevator car. With such systems, the dispatch controller assigns a particular car to service the call. While such systems allow for increased efficiency in transport capacity, particularly for larger buildings, they present certain challenges in some cases.

For example, many destination entry systems do not have hall lanterns at the entrance to the car, but rather have some other car indicator to allow passengers to know which car they intend to ride on. Without hall lanterns indicating the direction in which the car is moving, passengers may expect the car to ride in one direction, while the car will actually travel in the opposite direction. This can be a source of confusion for the passengers.

This is particularly problematic when the elevator car reaches a landing where the passenger is expected to board the elevator car, but the car is not yet traveling in the direction of the passenger's destination. It is possible for passengers to enter the car and travel in the wrong direction. The car is then returned to the landing where the passenger took the car. In this position, the system anticipates that a passenger will be riding on the car and uses some type of sensor to detect whether a person has entered the car. Because the passenger has already taken the car, the system assumes that there is no passenger and may cancel the destination to which the passenger is going. The passenger eventually becomes confused and can become frustrated because it appears to the passenger that the elevator system is malfunctioning.

Disclosure of Invention

An exemplary method of controlling an elevator system includes determining a source floor of a new call from a passenger desiring elevator service. The direction of travel from the source floor of the new call is also determined. The path of the elevator car under consideration is simulated as if the new call was assigned to the elevator car under consideration by determining at least one of (i) a relationship between a position of the elevator car under consideration and a source floor or (ii) a relationship between a direction of movement of the elevator car under consideration and a direction of travel. If the allocation will satisfy each of the following conditions: (i) assigning a new call to one of the plurality of elevator cars if the one of the elevator cars will not move in a direction opposite the direction of travel during a time between the passenger taking the one of the elevator cars and arriving at the passenger's destination and (ii) if the one of the elevator cars will not move in a direction opposite the direction of travel of any currently assigned passenger during a time between the currently assigned passenger taking the one of the elevator cars and arriving at the currently assigned passenger's destination.

The various features and advantages of an example embodiment will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

Drawings

Fig. 1 illustrates selected portions of an example elevator system in a schematic manner.

FIG. 2 is a flow chart summarizing one example approach.

Fig. 3 is a flowchart outlining an example algorithm for determining which of a plurality of elevator cars to assign to a particular call.

FIG. 4 is a flow diagram illustrating further details regarding a portion of the example of FIG. 3.

Fig. 5 is a flow diagram illustrating further details of a portion of the example of fig. 3.

Fig. 6 is a flow chart showing further details regarding the example of fig. 5.

Detailed Description

Fig. 1 schematically illustrates selected portions of an example elevator system 20. A plurality of elevator cars 22, 24 and 26 are provided for carrying passengers between different building floors as shown by floors 1-12 in fig. 1. Each elevator car 22, 24, and 26 is located in a hoistway 32, 34, and 36, respectively. For purposes of discussion, only three elevator cars are shown. Example implementations of the invention can be used with any number of elevator cars, as the case may be.

The example of fig. 1 includes a destination input device 40, the destination input device 40 configured to allow a passenger to request elevator service. The destination entry device 40 includes a passenger interface that allows a passenger to indicate a desired destination when the passenger is outside of an elevator cab (e.g., while still in a waiting room). Such devices are known. Fig. 1 includes another example passenger input device that includes hall call buttons 42. Hall call buttons allow a passenger at a particular building floor to indicate a desire to go up or down from that floor. Such devices are known.

The example of fig. 1 includes a dispatch controller 44 that assigns one of the elevator cars 22, 24 or 26 to a particular call based on a number of factors. The dispatch controller 44 in this example performs car assignment that minimizes the likelihood of causing passengers to become confused or frustrated by preventing or minimizing the instances when a passenger gets on an elevator car in a direction opposite to the direction in which the passenger needs to travel to reach their destination.

FIG. 2 is a flowchart diagram 50 summarizing one example approach. At 52, the dispatch controller 44 determines the source floor of the new call from the passenger desiring elevator service. At 54, the direction of travel from the source floor of the new call is determined. The direction of travel is the direction the passenger needs to travel to reach the intended destination. The new call may be placed using one of a variety of types of passenger input devices, such as a destination input device 40 or a hall call button 42. At 56, the dispatch controller 44 assigns the new call to one of the elevator cars such that during the time between each passenger boarding the car and reaching the passenger's corresponding destination, the elevator car will not move in a direction opposite the direction of travel of the new call or the currently assigned passenger for that car.

The disclosed examples avoid passenger confusion and frustration by avoiding situations where passengers will be carried in a direction opposite to the direction they need to travel to reach their intended destination. In addition, it is possible to avoid a situation in which the elevator controller may erroneously determine that the passenger is not riding on the elevator car and cancel the request in response.

There are a variety of algorithms for controlling the elevator system 20 to cause the dispatch controller 44 to allocate according to the example method outlined in fig. 2, with one particular algorithm being outlined in the flow charts of fig. 3-6. In fig. 3, the exemplary flowchart 60 begins with the scheduling algorithm starting at 62. In this example, the algorithm simulates the path of the elevator car in the case where a new call is assigned to the elevator car under consideration. A determination is made as to whether there will be a situation where the elevator car is traveling in a direction opposite to the direction that the passenger issuing the new call needs to travel to reach the intended destination. If this is the case, different ones of the elevator cars are considered.

In some examples, it is not possible to assign calls to any of the elevator cars without at least some travel in the opposite direction. In such cases, various criteria may be used to select the best of the elevator cars based on factors such as minimum wait time, minimum amount of reverse travel, e.g., to minimize the number of times the elevator car stops or to minimize overall elevator car movement. Those skilled in the art who have the benefit of this description will be able to select appropriate criteria to address such situations.

In the example of FIG. 3, a penalty value is initiated at 64. The penalty value indicates whether the candidate car can be assigned to a new call in this example. In this example, when the penalty value is false, then no penalty associated with assigning a new call to a particular elevator car is indicated. If this is the case, the elevator car is a suitable candidate to be assigned to the new call. Of course, additional criteria may be utilized to select the best candidate for any available candidate elevator cars for a particular new call. The algorithm outlined in flowchart 60 is preset to simulate the car travel path of each elevator car under consideration to determine whether it is a suitable candidate for call assignment. The details of how to select from more than one available candidate car, where there is more than one, are outside the scope of this disclosure.

At 65, a determination is made as to whether the candidate elevator car is stopping at the source floor at which the new call will originate. In other words, the determination at 65 determines whether the candidate elevator car is stopped at the floor at which the passenger desires to pick up the elevator car. The determination at 65 includes determining whether the car door is open. If the elevator car stops at the source floor and the doors are opened, a determination is made as to whether the car is moving downward and the direction associated with the new call is upward, as indicated at 66. If this is the case, the penalty value is set to true at 68. Once the penalty value is true for a particular elevator car, it is returned or reported at 70. In this example, the penalty value is the true disqualifying of an elevator car as an assigned candidate for a new call.

Assuming the determination at 66 is negative, a determination is made at 72 as to whether the car direction is up and the call direction is down. If this is the case, the penalty value is set to true at 74. This is then returned or reported at 70.

Assuming the determination at 65 is negative, the next step in the example of FIG. 3 is shown at 76. As can be appreciated from the figure, if the determination at 65 is positive and the determinations at 66 and 72 are negative, then a determination at 76 will also be made. At 76, a determination is made as to whether there is a hall call at the source floor that requires the car to travel in the direction opposite to the direction of the new call under consideration. If this is the case, the penalty value is set to true at 78 and reported at 70. If the determination at 76 is negative, a determination is made at 80 as to whether the car direction is downward. This car direction is the current direction of movement of the elevator car in question. Assuming it is down, another determination is made at 82 as to whether the direction associated with the new call is also down.

Based on the affirmative determination at 82, a determination is made at 84 whether the call source is under the current position of the car. This is based on e.g. determining the source floor of the new call and the current position of the elevator car under consideration. Assuming the call source floor is below an elevator car, a determination is made at 86 as to whether the call destination is below the currently assigned lowest demand for that particular elevator car. If this is the case, a determination is made at 88 based on the current assignment for that car, whether there are any reverse hall calls in the lowest demand and whether there are current car calls or an expected car call at the lowest demand that the elevator car is currently operating.

When the determination at 88 includes a positive conclusion, the elevator car cannot service the call, and the penalty value is set to true at 90. On the other hand, if the determination at 88 yields a negative conclusion, the penalty value is still false and the algorithm follows the path shown at 92, where the penalty value is reported at 70. In these latter cases, the elevator car under consideration is a valid candidate to receive the assignment of the new call under consideration.

A positive result at 86 was previously considered, but it is now assumed that the determination made at 86 leads to a negative conclusion. The next step in the illustrated example is shown at 94 where a determination is made as to whether the call destination is located on the lowest demand assigned by the current run of elevator cars. If this is the case, another determination at 96 includes considering whether an inverse hall call exists at the destination floor. When present, the elevator car is not a valid candidate for a new call and the penalty value is set to true at 98.

If the determination made at 94 or 96 yields a negative conclusion, the exemplary algorithm follows the path shown at 100 and reports a false penalty value at 70. In either of those cases, the elevator car is a valid candidate and a new call may be assigned to it.

The previous discussion assumed that the determination at 84 reached a positive conclusion. Now assume that the call source is not below car and the conclusion at 84 is negative. Then a determination is made at 106 as to whether the call source is below the highest demand floor for that elevator car, given the current assignment to that elevator car. If this is the case, a determination is made at 108 as to whether there is an expected car call at the source floor on which the new call originated. If this is the case, the penalty is set to true at 110 and the elevator car is not eligible for the assignment of a new call. If the determination at 108 is that there is no expected car call at the source of the new call, the example algorithm follows the path shown at 104 and reports a false value for the penalty at 70. In this case, the elevator car under consideration is a valid candidate for the assignment of a new call.

Assume now that the determination at 106 yields a negative determination because the call source is not below the highest demand. A determination is made at 112 whether the call source is above the highest demand. If this is not the case, the algorithm follows the path at 114 and reports a false value of penalty at 70. If the call source is above the highest demand, as determined at 112, then a determination at 116 is made. This determination is whether there is an inverse hall call at the highest demand for that car and whether there is a car call or an expected car call at the highest demand. If the determination at 116 contains a negative conclusion, the path at 114 is followed to report a false value for the penalty. On the other hand, if the determination at 116 is a positive conclusion, then the penalty is set to true at 118 and the elevator car is not a qualified candidate for new call assignment.

The above discussion assumes that the determination made at 82 results in a positive conclusion (i.e., the elevator car is down and the call direction is down). Assume now that the determination at 82 yields a negative determination because the call direction is up when the elevator car direction is down as determined at 80. In these cases, the steps outlined in fig. 4 will be followed, as indicated by the connection points 120 in fig. 3.

As shown in fig. 4, a determination is made at 122 as to whether the elevator car under consideration is stopping, the source of the new call is the same car position, and the source of the call is not equal to the lowest demand. If this is the case, the penalty value is set to true at 124 and reported at 70. If the condition at 122 is not met, a determination is made at 126 as to whether the destination of the new call is above cars, but below the highest demand for cars, given the current assignment of cars. If this is the case, a determination is made at 128 as to whether a reverse hall call exists at the destination floor. When the determination at 128 yields a positive result, the penalty value is set to true at 130 and then returned at 70.

If the determination made at 126 yields a negative result, a determination is made at 132 as to whether the highest demand is above car and the destination or call source of the new call is above the highest demand. If this is the case, the example in FIG. 4 proceeds to 134 where a determination is made as to whether there is a reverse hall call at the location of the highest demand and whether there is an expected car call at the highest demand. If this is the case, the penalty value is set to true at 136.

If the determination made at any of 128, 132 or 134 yields a negative result, a determination is made at 138 as to whether the call source is at or below the position of the car. If this is not the case, the algorithm follows the path shown at 140 to return a false penalty value, meaning that the elevator car is a valid candidate for possible assignment of a new call. On the other hand, when the call source is at or below the elevator car position as determined at 138, a next determination is made at 142 to determine if the call source is below the lowest demand. When this is the case, a determination is made at 144 as to whether there is an opposing hall call at the lowest demand and a car call or an expected car call is also at the lowest demand. If those conditions are met, the penalty value is set to true at 146. When the determination at 144 is concluded negatively, a false penalty value is reported because the penalty reporting step 70 is reached following the path at 148.

Referring again to the determination at 142, when the call source is not below the lowest demand for the elevator car, a next determination is made at 150 as to whether the call source is above the lowest demand. If this is not the case, the path at 140 is followed and the penalty value false is reported at 70. On the other hand, when the call source is above the lowest demand, the determination at 152 indicates whether there is a car call or an expected car call at the source floor of the new call. If this is the case, the penalty value is set to true at 154. If the determination at 152 yields a negative result, the path at 140 is followed and a false penalty value is reported at 70 because the elevator car under consideration is a candidate for a new call assignment.

Each of the steps followed in fig. 4 is performed under the assumption that the determination at 80 yields a positive result and the determination at 82 yields a negative result in fig. 3. In some cases, the determination at 80 as to whether the car is heading down will be negative because the car is heading up. In these cases, the determination shown in the flow chart of FIG. 5 would follow a path to the connection point 160.

In fig. 5, a first determination is shown at 162. At this point, a determination is made as to whether the call direction is up, which in this example would mean that the call direction is the same as the car direction. If this is the case, a determination is made at 164 as to whether the call source is at or above car position. If this is the case, then a determination is made at 166 as to whether the call destination is above the highest demand, given the current assignment of that car. When the call destination is above the highest demand, a determination is made at 168 as to whether there is an inverted hall call and a car call or an expected car call at the highest demand. If this is the case, the penalty value is set to true at 170. When the determination at 168 yields a negative result, the example of FIG. 5 follows the path shown at 172 and reports a false penalty value at 70. The condition indicates that the elevator car under consideration is a valid candidate for new call assignment.

Reviewing the determination at 166, if the call destination is not above the highest demand, a determination is made at 174 as to whether the call destination is below the highest demand. If this is the case, the determination at 176 indicates whether there is a reverse hall call at the destination floor. If this is the case, the penalty value is set to true at 178 and reported at 70. If the determination made at 174 or 176 yields a negative result, then the car under consideration is a valid candidate for the assignment of a new call and will follow the path at 180 in FIG. 5.

If the determination at 164 yields a positive result, then steps 166-178 are performed. However, when the call source is not above the elevator car as determined at 164, a next determination is made at 184 as to whether the call source is above the lowest demand. When the result at 184 is positive, a determination is made at 186 as to whether there is an expected car call at the call source floor. If this is the case, the penalty value is set to true at 188. On the other hand, if the determination made at 186 yields a negative result, the path at 190 will be followed and a false penalty value will be reported at 70.

When the determination at 184 that the call source is above the lowest demand yields a negative result, the illustrated example proceeds to 192. Here, a determination is made as to whether the call source is below the lowest demand for the elevator car. If this is the case, the determination at 194 indicates whether there is an opposing hall call and a car call or an expected car call at the lowest demand. When those conditions are met, the penalty value is set to true at 196 and the car is not considered eligible for a new call. On the other hand, if the determination made at 192 or 194 yields a negative result, the path at 198 is followed and the elevator car will be considered a valid candidate for the new call.

From the above description, when the determination at 162 indicates that the call direction is up, steps 164-196 shown in FIG. 5 are followed. On the other hand, if the call direction is down, the example algorithm proceeds to connection point 200 such that the process outlined in FIG. 6 provides an indication that the assigned car is eligible or not.

As shown in fig. 6, assuming a negative determination at 162 (fig. 5), then a determination is made at 202 as to whether the car is stopping, the call source is on the same floor as the elevator car location, and the call source is not the highest demand. If this is the case, the penalty value is set to true at 204 and reported at 70. On the other hand, if the condition at 202 is not met, then a determination is made at 206 as to whether the call destination is below the car but above the lowest demand for the car. If this is the case, a determination is made at 208 as to whether a reverse hall call is present at the destination floor. When this is the case, the penalty value is set to true at 210. At this point, this elevator car will not be considered a valid candidate and a penalty value is returned at 70.

When the determination at 206 yields a negative result, a determination is made at 212 as to whether the lowest demand for that car is below the car and the destination or call source for the new call is below the lowest demand. When those conditions are met, then a determination is made at 214 as to whether there is an inverse hall call at the lowest demand location and whether there is an expected car call. Under those conditions, the penalty value is set to true at 216.

If the determination made at 208, 212, or 214 yields a negative result, the next step in the illustrated example is shown at 218. At this point, a determination is made as to whether the call source is at or above the elevator car position. When this is the case, the determination at 220 indicates whether the call source is above the highest demand. When the determination at 220 yields a positive result, a determination is made at 222 as to whether there is an inverted hall call along with a car call or an expected car call at the highest demand. When those conditions are met, the elevator car should not be considered a valid candidate for new call assignment and the penalty value is set to true at 226. On the other hand, when the determination at 222 yields a negative result, the penalty value is still false by following the path shown at 224 and reporting it at 70.

Reviewing the determination at 220, when the call source is not above the highest demand, the illustrated example includes a determination at 228 as to whether the call source is below the highest demand. When this is the case, another determination at 230 indicates whether a car call or an expected car call is present at the source floor. If this is the case, the penalty value is set to true at 232. When a negative result is obtained in the determination at 230, 228 or 218, the path shown at 234 in figure 6 is followed to report a false penalty value at 70. In either of those conditions, the elevator car under consideration may be assigned a new call.

As an example scenario, assume that a new call is initiated at floor 8 in fig. 1 using destination input device 40. The new call includes an indication of the passenger's willingness to travel up to floor 12. For purposes of discussion, the elevator car 22 is currently at floor 7 and is traveling down to the first floor without an intermediate stop. The elevator car 24 is traveling from the first floor up to the 7 th floor and stops midway on floor 5. Elevator car 26 is currently stopped at floor 8 and the doors are open for the purpose of responding to an upward hall call. A passenger placing the hall call enters elevator cab 26 and indicates a desire to travel to floor 10.

Turning now to the example algorithm outlined in fig. 3-6, consider first the elevator car 22. Beginning at 62 in fig. 3, the penalty value for the elevator car 22 is currently set to false, according to step 64. The determination at 65 yields a negative result because the car is not stopped at the source floor. The next step is 76 where a determination is made as to whether a reverse hall call is present at the source floor. The result of this query is negative and a determination is made at 80 as to whether the car direction is downward. Elevator car 22 is currently traveling from floor 7 to the first floor. The answer to the query at 80 is affirmative and a determination is made at 82 as to whether the call direction is down. In this example, the call direction would be up because the passenger desires to go from floor 8 to floor 12. Accordingly, the connection point 120 is followed into fig. 4. The determination at 122 is negative because the car is not stopping and the call source is not the same as the car position. The next determination at 126 yields a negative result because the call destination for the new call is above the elevator car, but not below the highest demand for the car. This would require following the flow of fig. 4 to step 132. The result of this determination would be negative because the highest demand on the car 22 is not higher than the car. This leads to a determination at 138 where a determination is made as to whether the call source is below the elevator car. In this example, the call source is floor 8, and elevator car 22 is currently at floor 7. Thus, the determination at 138 would be negative and the penalty would remain false, reporting it at 70. In other words, the elevator car 22 is a valid candidate for a new call assignment because assigning a call to it does not result in the direction of movement of the elevator car 22 being opposite the direction of travel required by the passenger who placed the new call during the time between when the passenger will board the elevator car 22 and reaching the destination floor 12. In this example situation, the elevator car 22 will return to the first floor before a passenger on floor 8 can board the car. The car 22 may then travel upward to handle the new call.

Consider the car 24 and start with the determination at 65 in fig. 3, the car 24 is not stopped at the source floor. Thus, a next determination is made at 76 wherein the question of whether a reverse hall call exists at the source floor must be answered. In the assumed case, this is not the case and the next query is made at 80. The direction of the elevator car 24 is upward and so the result would be to go to the connection point 160 and proceed with the algorithm of fig. 5. The next determination would be whether the call direction is up, as shown at 162. The answer to the question is positive so at 164 the next determination is whether the call source is above the elevator car. Given that the call source is floor 8 and that car 24 is currently on the first floor, the determination at 164 is positive. The next question is answered at 166, whether the call destination is above the highest demand for the car 24. The answer to the question is positive. A next determination is made at 168 as to whether the reverse hall call is at the highest demand (e.g., floor 7), and whether there is a car call or an expected car call at the highest demand. The answer to the question is negative in the assumed case and the path shown at 172 will be followed. In other words, in this case, elevator car 24 is a valid candidate for new call assignment.

Turning to the elevator car 26 and referring to fig. 3, the determination at 65 yields a positive result because the car 26 is stopped at the source floor of the new call and the elevator car doors are currently open. The next determination is made at 66 as to whether the car is down and the call is up. Given that the elevator car 26 is moving upward, the answer is negative and a next determination must be made at 72. In this case, the car direction is up and the call direction is up, so that the determination made at 72 yields a negative result. This requires following the determined path to 76. Given the assumptions, there is no reverse hall call on floor 8. A next determination is then made at 80 as to whether the car direction is up or down. In this case, car 26 is moving upward, so the flow continues to the connection point at 160. A determination is then made at 162 (fig. 5) as to whether the car direction is upward. Given the passenger's desire to go from floor 8 to floor 12, the answer to the query at 162 is affirmative.

The determination at 164 indicates whether the call source is at or above car position. With both the given car and the call source at floor 8, an affirmative result follows the flow to the determination at 166. In this case, in fact, the call destination is above the highest demand, which yields a positive result. Flow continues to connection point 168 where a determination is made as to whether there is an opposing hall call along with a car call or an expected car call at the current highest demand. Because there is only one car call, the answer to the question is negative and the path shown at 172 will be followed to report a false penalty value at 70. Elevator cab 26 is a valid candidate for a new call.

Given that all three example cars can be assigned a new call, other criteria will be used to select one of those elevator cars. Given a situation according to one example, it is most likely that a new call will be assigned to elevator car 26 because that will provide the shortest waiting time for the passenger. Car 26 is already at floor 8 and passengers can immediately board the car as expected. If for some reason it would appear that it is unlikely that a passenger will be able to board the car (e.g., the elevator car is already fully loaded), then elevator car 24 may be the next best choice because it may be possible to reach floor 8 before elevator car 22 is able to reach floor 8 to carry the passenger who issued the new call. Other criteria may also be used to select between available candidate cars. Given this description, those skilled in the art will be able to set appropriate criteria to meet their particular needs for such a situation.

If any of cars 22, 24 or 26 is positioned such that its corresponding penalty value is set to true when following the path of the illustrated flow chart, then that car will be removed from consideration and not considered a candidate car. Such elevator cars will travel in the opposite direction to the direction in which the new call is requested to travel between the time the passenger will board the car and the time of arrival at the new call destination.

The illustrated example provides techniques for controlling an elevator system in a manner that avoids passenger confusion and frustration by reducing or eliminating reverse travel conditions during which passengers may enter an elevator car and be carried in a direction opposite the direction of travel in which they expect to reach their desired destination.

The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

Claims (17)

1. A method of controlling an elevator system, characterized in that the method comprises the steps of:

determining a direction of travel from a source floor of a new call from a passenger desiring elevator service;

simulating a path of a considered elevator car in the event the new call is assigned to the considered elevator car by determining at least one of the following relationships:

(i) the relation between the position of the elevator car under consideration and the source floor and

(ii) a relation between the direction of movement of the considered elevator car and the direction of travel; and

assigning the new call to one of a plurality of elevator cars if the assigning would satisfy each of the following conditions:

(i) during the time between a passenger riding on one of the elevator cars and arriving at the passenger's destination, one of the elevator cars will not move in a direction opposite the direction of travel, an

(ii) During the time between a currently assigned passenger riding on one of the elevator cars and arriving at the destination of the currently assigned passenger, one of the elevator cars will not move in a direction opposite the direction of travel of any currently assigned passenger.

2. The method of claim 1, comprising:

assigning the new call to one of the plurality of elevator cars if the assigning would not cause one of the elevator cars to stop at the source floor of the currently assigned passenger and then move in a direction opposite the direction from the source floor of the currently assigned passenger to the destination of the currently assigned passenger.

3. The method of claim 2, comprising:

determining at least one of:

the source floor of the new call or the destination of the new call is above or below the highest or lowest demand for the elevator car under consideration;

whether the elevator car under consideration has a call waiting at the source floor or the destination;

whether the elevator car under consideration has a hall call waiting at the source floor, the hall call having a direction of movement opposite the direction of travel; and

the elevator car under consideration has a call or an expected call waiting at the highest demand for the elevator car under consideration or at the lowest demand for the elevator car under consideration.

4. The method of claim 1, comprising:

determining whether the elevator car under consideration is located at the source floor;

determining whether the considered elevator car will move in a direction opposite the direction of travel; and

designating the considered elevator car as being unconditional to the assignment of the new call when the considered elevator car is at the source floor and is to be moved in a direction opposite the direction of travel.

5. The method of claim 1, comprising:

determining whether the direction of travel is the same as the direction of movement of the elevator car under consideration; and

determining whether the source floor is above or below the considered elevator car.

6. The method of claim 5, wherein the direction of travel is the same as the direction of movement of the considered elevator car, the method comprising:

designating the considered elevator car as a candidate for assignment of the new call when the source floor is not lower than the considered elevator car and the source floor is not higher than the considered elevator car.

7. The method of claim 5, wherein the direction of travel and the direction of movement are both downward and the source floor is below the considered elevator car, the method comprising:

determining whether the destination of the new call is above or below a lowest demand for the elevator car under consideration; and

at least one of the following:

(i) designating the considered elevator car as a valid candidate for assignment of the new call if the destination of the new call is not below or above the lowest demand;

(ii) designating the considered elevator car as a valid candidate for assignment of the new call if the destination of the new call is below the lowest demand and there is no reverse hall call at the lowest demand or no car call or expected car call at the lowest demand;

(iii) designating the considered elevator car as ineligible for assignment of the new call if the destination of the new call is below the lowest demand and there is an inverse hall call at the lowest demand and there is a car call at the lowest demand or there is an expected car call at the lowest demand;

(iv) designating the considered elevator car as a valid candidate for assignment of the new call if the destination of the new call is above the lowest demand and there is no reverse hall call at the destination of the new call; and

(v) designating the considered elevator car as ineligible for assignment of the new call if the destination of the new call is above the lowest demand and there is an inverse hall call at the destination of the new call.

8. The method of claim 5, wherein the direction of movement and the direction of travel are both downward and the source floor is above the considered elevator car, the method comprising:

determining whether the source floor is above or below a highest floor demand for the considered elevator car; and

at least one of the following:

(i) designating the considered elevator car as a valid candidate for assignment of the new call if the source floor of the new call is not below or above the highest demand;

(ii) designating the considered elevator car as a valid candidate for assignment of the new call if the source floor of the new call is below the highest demand and there is no expected car call at the source floor;

(iii) designating the considered elevator car as ineligible for assignment of the new call if the source floor of the new call is below the highest demand and there is an expected car call at the source floor;

(iv) designating the considered elevator car as a valid candidate for assignment of the new call if the source floor of the new call is above the highest demand and there is no reverse hall call at the highest demand or no car call at the highest demand or no expected car call at the highest demand; and

(v) designating the considered elevator car as ineligible for assignment of the new call if the source floor of the new call is above the highest demand and there is an inverse hall call at the highest demand and a car call or an expected car call at the highest demand.

9. The method of claim 5, wherein the direction of travel and the direction of movement are both upward and the source floor is at or above the considered elevator car, the method comprising:

determining whether the destination of the new call is above or below a highest demand for the considered elevator car; and

at least one of the following:

(i) designating the considered elevator car as a valid candidate for assignment of the new call if the destination of the new call is not below or above the highest demand;

(ii) designating the considered elevator car as a valid candidate for assignment of the new call if the destination of the new call is below the highest demand and there is no hall call at the destination, the hall call having a direction opposite the direction of travel;

(iii) designating the considered elevator car as ineligible for assignment of the new call if the destination of the new call is below the highest demand and there is a hall call at the destination, the hall call having a direction opposite the direction of travel;

(iv) designating the considered elevator car as a valid candidate for assignment of the new call if the destination of the new call is above the highest demand and there is no hall call at the highest demand for the considered elevator car, the hall call having a direction opposite the direction of travel or no car call at the highest demand or no expected car call at the highest demand; and

(v) designating the considered elevator car as ineligible for assignment of the new call if the destination of the new call is above the highest demand and there is a hall call at the highest demand for the considered elevator car, the hall call having a direction opposite the direction of travel and there is a car call or an expected car call at the highest demand.

10. The method of claim 5, wherein the direction of travel and the direction of movement are both upward and the source floor is below the considered elevator car, the method comprising:

determining whether the source floor is above or below a lowest floor demand for the considered elevator car; and

at least one of the following operations

(i) Designating the considered elevator car as a valid candidate for assignment of the new call if the source floor of the new call is not below or above the lowest demand;

(ii) designating the considered elevator car as a valid candidate for assignment of the new call if the source floor of the new call is above the lowest demand and there is no expected car call at the source floor;

(iii) designating the considered elevator car as ineligible for assignment of the new call if the source floor of the new call is above the lowest demand and there is an expected car call at the source floor;

(iv) designating the considered elevator car as a valid candidate for assignment of the new call if the source floor of the new call is below the lowest demand and there is no hall call at the lowest demand, the hall call having a direction opposite the direction of travel or there is no car call at the lowest demand or there is no expected car call at the lowest demand; and

(v) designating the considered elevator car as ineligible for assignment of the new call if the source floor of the new call is below the lowest demand and there is a hall call at the lowest demand, the hall call having a direction opposite the direction of travel and there is a car call or an expected car call at the lowest demand.

11. The method of claim 5, wherein the direction of travel is different from the direction of movement, the method comprising at least one of:

designating the considered elevator car as a valid candidate for assignment of the new call if the source floor is above the considered elevator car when the direction of travel is up and the direction of movement is down;

designating the considered elevator car as a valid candidate for assignment of the new call if the source floor is below the considered elevator car when the direction of travel is downward and the direction of movement is upward.

12. The method of claim 5, wherein the direction of travel is upward, the direction of movement is downward, and the source floor is below the considered elevator car, the method comprising:

determining whether the source floor is above or below a lowest floor demand for the considered elevator car; and

at least one of the following:

(i) designating the considered elevator car as a valid candidate for assignment of the new call if the call source is not below the lowest demand and not above the lowest demand;

(ii) designating the considered elevator car as a valid candidate for assignment of the new call if the source floor is below the lowest demand and there is no hall call at the lowest demand, the hall call having a direction opposite the direction of travel, or there is no car call or expected car call at the lowest demand;

(iii) designating the considered elevator car as ineligible for assignment of the new call if the source floor is below the lowest demand and there is a hall call at the lowest demand, the hall call having a direction opposite the direction of travel, and there is a car call or an expected car call at the lowest demand;

(iv) designating the considered elevator car as a valid candidate for assignment of the new call if the source floor is above the lowest demand and there is no car call or expected car call at the source floor; and

(v) designating the considered elevator car as ineligible for assignment of the new call if the source floor is above the lowest demand and there is a car call or an expected car call at the source floor.

13. The method of claim 5, wherein the direction of travel is downward, the direction of movement is upward, and the source floor is above the considered elevator car, the method comprising:

determining whether the source floor is above or below a highest floor demand for the considered elevator car; and

at least one of the following:

(i) designating the considered elevator car as a valid candidate for assignment of the new call if the call source is not below a lowest demand and not above the highest demand;

(ii) designating the considered elevator car as a valid candidate for assignment of the new call if the source floor is above the highest demand and there is no hall call at the highest demand, the hall call having a direction opposite the direction of travel, or there is no car call at the highest demand or there is no expected car call at the highest demand;

(iii) designating the considered elevator car as ineligible for assignment of the new call if the source floor is above the highest demand and there is a hall call at the highest demand, the hall call having a direction opposite the direction of travel, and there is a car call at the highest demand or an expected car call at the highest demand;

(iv) designating the considered elevator car as a valid candidate for assignment of the new call if the source floor is below the highest demand and there is no car call or expected car call at the source floor; and

(v) designating the considered elevator car as ineligible for assignment of the new call if the source floor is below the highest demand and there is a car call or an expected car call at the source floor.

14. The method of claim 1, comprising:

determining that the direction of travel is different from the direction of movement of the elevator car under consideration; and

designating the considered elevator car as not eligible for assignment of the new call if the considered elevator car stops at the source floor of the new call.

15. The method of claim 1, comprising:

determining that the direction of travel is different from the direction of movement of the elevator car under consideration;

determining whether the destination of the new call is:

(a) above the considered elevator car and below the highest floor requirement for the considered elevator car or

(b) Below the considered elevator car and above the lowest floor demand for the considered elevator car; and

designating the considered elevator car as ineligible for assignment of the new call if there is a hall call at the destination, the hall call has a direction opposite the direction of travel, and the destination satisfies the condition of (a) or (b).

16. The method of claim 1, comprising:

determining that the direction of travel is different from the direction of movement of the elevator car under consideration;

determining whether the destination of the new call is:

(i) above the considered elevator car and below the highest floor requirement for the considered elevator car or

(ii) Below the considered elevator car and above the lowest floor demand for the considered elevator car; and

at least one of the following:

designating the considered elevator car as ineligible for assignment of the new call if (a) a lowest demand on the considered elevator car is below the considered elevator car and the source floor or the destination is below the lowest demand and (b) there is a hall call at the lowest demand, the hall call having a direction opposite the direction of travel, and there is an expected car call at the lowest demand; and

designating the considered elevator car as ineligible for assignment of the new call if (a) a highest demand for the considered elevator car is above the considered elevator car and the source floor or the destination is above the highest demand and (b) there is a hall call at the highest demand, the hall call having a direction opposite the direction of travel, and there is an expected car call at the highest demand.

17. An elevator system, comprising:

a plurality of elevator cars;

at least one passenger input device configured to allow a passenger to place a new call for elevator service; and

a scheduling controller configured to:

determining a direction of travel from a source floor of a new call from a passenger desiring elevator service;

simulating a path of a considered elevator car in the event the new call is assigned to the considered elevator car by determining at least one of the following relationships:

(i) the relation between the position of the elevator car under consideration and the source floor and

(ii) a relation between the direction of movement of the considered elevator car and the direction of travel; and

assigning the new call to one of a plurality of elevator cars if the assigning would satisfy each of the following conditions:

(i) during the time between a passenger riding on one of the elevator cars and arriving at the passenger's destination, one of the elevator cars will not move in a direction opposite the direction of travel, an

(ii) During the time between a currently assigned passenger riding on one of the elevator cars and arriving at the destination of the currently assigned passenger, one of the elevator cars will not move in a direction opposite the direction of travel of any currently assigned passenger.