1. Field of the Invention
The present invention relates to casino gaming and, in particular, to gaming machines having mechanical bonus wheels.
2. Discussion of the Background
Before the advent of modern day computers, gaming regulators approved gaming machines that were purely mechanical in nature. Many gaming machines used mechanical reels and/or wheels. At the time of the mechanical spin, the spin outcome was unknown. Today, regulators hold new gaming machines to a much higher standard. Prior to the reel or wheel spin, the outcome is already known, and machines are generally required to check that the spin outcome depicted matches the predetermined outcome. Another important facet of today's gaming machine is the ability, within the precision required by gaming regulators, to demonstrate a calculable and predictable “expected return” on the part of the player (or alternately from the point of view of the house, “house advantage”).
Novel bonus games, particularly those encompassing a mechanical apparatus, are popular in current casino gaming machines. When a bonus game is combined with an underlying slot machine, the entire game must comply with regulatory requirements. As such, bonus games of a mechanical nature are desirable (due to eye-candy appeal to players) but, too often, resort to predetermined outcomes (due to regulatory hurdles).
The use of a wheel in a casino game top box is conventional, such as that found in mechanical wheel games of U.S. Pat. Nos. 5,823,874 and 5,848,932. In these wheel bonus games, a static indicator (stationary pointer) remains motionless while an adjacent mechanical wheel rotates. In this approach, the wheel gradually slows down and stops, with the segment on the wheel indicated by the pointer representing the player's win. The “MONTE CARLO” from Bally Corporation top box concept (originally a 1970s game with a “parallel” bonus in which the player continued to wager, and recently revived by Bally as a conventional bonus game with the same name) takes a slightly different approach in which the mechanical indicator is dynamic (moving pointer) while the wheel is static. In the Bally approach, the pointer rotates, in the plane of the surface of the wheel, and stops, with the segment on the wheel indicated by the pointer representing the player's win. Both of these current approaches utilize a predetermined outcome, such as a computer controlling a stepper motor to stop the wheel at a precise, predetermined outcome (i.e., a segment of the wheel having a “value”)—the actual spin of the “wheel” is simply a cosmetic fait accompli.
The California Lottery has a TV game trademarked “THE BIG SPIN” in which a free moving ball is housed internally in a wheel whose segments depict awards. The wheel is spun by a contestant to determine the contestant's award. The free moving and usually bouncing ball finally lands in a segment representing the winning award. The California Lottery Commission retains an independent auditor to carefully examine and test the wheel and equipment prior to each television show. However, from a gaming perspective, having people check the equipment, such as prior to each play (or each hour or each day), is completely impractical, as hundreds or thousands of operations (i.e., game plays) may occur on each of the hundreds or thousands of gaming devices every day in the casino environment. Similarly, it is also impractical to have the player physically spin the wheel while an agent of the casino visually determines the outcome. THE BIG SPIN wheel freely spins and the ball freely lands in an award segment. The contestant views the wheel spin, which is witnessed by the state and further “verified” by a live television audience. This represents a methodology that is highly impractical and/or would not pass regulatory approval for automated slot machine use in a casino.
Roulette and the large casino wheels such as the Big Six wheel are considered casino table games and do not have the same regulatory hurdle of slot/automated gaming machines due to the presence of a casino employee at each spin. In the sense of having a casino/lottery agent verifying game outcome, THE BIG SPIN wheel is similar to the Big Six wheel.
In U.S. Pat. No. 6,047,963, any bias in the mechanical components of the Pachinko top box, as a bonus game to an underlying casino slot machine, is eliminated. Lane values are randomly selected and “locked-in” to the lanes. Thereafter, a ball is released from the top of the playfield and, after traversing a forest of deflecting pins, settles into a lane. The lane “selected” by the ball represents the player's win. A distinct advantage to this approach is that the influence of any mechanical imperfections or biasing problems are eliminated by the disclosed methodology of assigning lane values, such that both the player and the casino are protected from faulty equipment. As a corollary, neither the casino nor the regulators need to check the Pachinko equipment any more often than usual.
While modern bonus “wheels” in gaming devices have been successful, nevertheless a player may feel that the gaming machine is controlling the outcome, because the final arrangement of the indicator and wheel, in these modern versions, is carefully controlled by a processor and a stepper motor and in no way represents free motion. Indeed, the final outcome of the wheel game is predetermined before the “spin” even begins. For example, in current wheel bonus games, it is common for the wheel to come to rest at a nominal value (say, $25), having just passed an adjacent segment of high value (say, $500). Although this leads to some suspense on the part of the player, it also may lead the player to a feeling of “undue control” by the gaming machine.
The Pachinko approach discussed above alleviates this problem in that, once the lane values are randomly locked-in, the free motion of the Pachinko ball dictates the outcome of the game. The contrivance of a pre-determined outcome to the various possible awards is eliminated, to the benefit of the players.
A need exists to develop a mechanical wheel-type casino game of chance in which the final outcome is not predetermined and controlled precisely by a computer in the gaming machine.
A further need exists to develop a mechanical wheel-type of casino game of chance in which free motion is used to determine the final outcome.
A need further exists to develop a mechanical wheel-type of casino game of chance in which both the “indicator” and the “wheel” have dynamic mechanical motion, instead of one or the other being static. It would be desirable to use a freely moving ball, or similar bouncing object, as the indicator.
A need further exists to develop a wheel-type of casino game of chance similar to the California Lottery THE BIG SPIN wheel, wherein the spin and determination of the outcome are performed automatically, and wherein the expected value of such a casino game is nevertheless calculable and controlled to mitigate mechanical bias, such that the game may be approved by regulators. Because of the free-motion nature of the game, it would be further desirable to self-monitor the outcomes to check that no mechanical bias has crept in.
A final need exists to incorporate such features in a casino game of chance as a bonus game to underlying gaming machines such as slot gaming machines.
The aforementioned needs are attained through the following inventions.
A free-motion ball serves as a dynamic internal indicator and is housed in a rotatable mechanical wheel, divided into segments each with an award value, driven by a processor-controlled stepper-motor. The wheel is spun, thus agitating the free-motion ball and making it bounce considerably within the wheel housing, and then slowly the wheel is brought to a stop. The ball's final resting segment on the wheel determines the award.
The novel casino game of chance and method comprises a unique arrangement of the award values of the wheel segments, a predetermined stopping orientation of the wheel, and a geometry of the ball/segments/pins such that the ball must come to rest in specific predefined wheel “possible outcome segments” relative to the stopping orientation of the wheel. The combination of these attributes provides a calculable expected value, which can be controlled even with biased equipment, while allowing free-motion of the ball. In this manner, all of the needs as stated previously are fulfilled, giving the player a rewarding experience while protecting the casino and player.
a. Overview:
The mechanical wheel 10 assembly itself is comprised of a disc 12, as illustrated in
For a radius Rad from center 40 of wheel 10 to center of pin 20, and a number N of wheel segments 100, the chord distance D between adjacent centers of pins 20 is:
D=2Rad sin(180/N) (FORMULA 1)
For example, let N=30 segments and Rad=10 inches, then D=2.091 inches.
If an odd number of possible outcome segments in set 200 is desired, the wheel 10 will be stopped with one segment 100 centered on the bottom 50. If an even number of possible outcome segments in set 200 is desired, the wheel 10 will be stopped with a pin 20 on the bottom 50. For an odd number example, if seven possible outcome segments in set 200 are desired (as shown in
The manner in which this is accomplished is to choose a ball 150 having a diameter S (as shown in
The distance X (as shown in
X={Rad^2−(D/2)^2}^(½)−{(S/2)^2−(D/2)^2}^(½) (FORMULA 2)
In an example where Rad=10 inches, S=2.75 inches, and D=2.091 inches, then X=9.0519 inches.
Now, taking the x-y plane as that of the wheel 10, with the y-axis along the vertical and the x-axis along the horizontal as shown in
Whether an odd or an even number of possible outcome segments are used in a set 200, the number of sets 200 that can be randomly placed at the bottom 50 of the mechanical wheel 10 as shown in
b. Even Number of Possible Outcome Segments in Set 200:
This embodiment is illustrated in
For an even number of possible outcome segments 200, the nth segment's pins 20 (denoted a and b from the bottom 50) are located at x-positions:
x-position−na=Rad sin {(n−1)(360/N)} (FORMULA 3)
x-position−nb=Rad sin {n(360/N)} (FORMULA 4)
The x-position of ball 150 is as follows:
x-position−nball=X sin {(n−½)(360/N)} (FORMULA 5)
For ease of calculation, the examples assume x=0 is centered on the bottom 50 of the wheel 10. In principle, the origin (0,0) may be put elsewhere for these calculations with no change in solution.
To continue the above example, assume the following nominal values of N=30 segments, S=2.75 inches, Rad=10 inches, and the number of possible segment outcomes=8. For this example, the chord distance is D=2.091 inches between pin 20 centers around the periphery 30 and X=9.0519 inches as shown in
As another example, if nominal values of N=25 segments, S=2 inches, Rad=6 inches, and the number of possible outcome segments=6 are assumed, then D=1.504 inches and X=5.2935 inches. The results are shown in the table of
c. Odd Number of Possible Outcome Segments in Set 200:
As the wheel 10 stops, the solution is again described from the bottom 50 of the wheel 10. In this case, the bottom 50 of the wheel 10 is a segment 210 (instead of a pin 20 between segments 100 as discussed above) as shown in
For an odd number of possible outcome segments 200, the possible nth segment's pins (denoted a and b) are located at x-positions:
x-position−na=Rad sin {(n−½)(360/N)} (FORMULA 6)
x-position−nb=Rad sin {(n−½)(360/N)} (FORMULA 7)
The ball's x-position is as follows:
x-position−nball=X sin {(n−1)(360/N)} (FORMULA 8)
As an example, assume nominal values of N=22 segments, S=2.6 inches, the number of possible outcome segments in set 200 equals 7, and Rad=8 inches, which results in the table of
The discussion above assumes a thickness T (as shown in
It may be seen that, in practice, a wide variety of wheel sizes having different radii (Rad), number of segments (N), ball sizes (S), and desired number of possible outcome segments in set 200 into which the ball 150 may land may be designed.
What has been set forth above, under the teachings of the present invention, provides a plurality of possible outcome segments in a set 200 in which the ball 150 can land as the wheel stops. The ball lands in one possible outcome segment in the set just before, at, or just after the wheel is physically stopped (i.e., “as the wheel stops”). As shown, the teachings of the present invention show that a designer can adjust the number of segments, the radius of the wheel, the diameter of the ball, and the thickness of the pin to arrive at an actual mechanical casino wheel game of the present invention. As taught herein, the wheel spins and the ball freely moves and lands in only one of several predetermined possible outcome segments in a set 200 as defined relative to a final stopping orientation of the wheel.
d. Stepper Motor Control:
In the preferred embodiment as functionally shown in
Any suitable processor-controlled electro/mechanical device coupled to the wheel 10 can be used under the teachings of the present invention to effectuate spinning and then stopping of the wheel 10 at a predetermined location 520 at bottom 50. In a vertically oriented mechanical wheel, the predetermined location is preferably the bottom 50. Other embodiments are more vigorous and may use other predetermined locations. By way of example, the predetermined location could be at any one of the other possible outcome segments. The wheel need not be vertical but may be tilted.
The manner in which the possible outcome segments in a set 200 are assigned values, and the probability distribution associated with location 520 at which the wheel 10 is stopped, to yield a desired expected value and control bias is discussed next for the casino game of chance of the present invention.
e. Player Expected Value Determination:
Assume that the wheel 10 has been stopped in a particular location by the stepper control 500, and that the ball 150 will now settle (land) into one of the possible outcome segments in the set 200 positioned at that location. For simplicity, assume there are three possible outcome segments in set 200 (Bottom, Left, and Right) and that the probability distribution among these possible outcome segments in set 200 is unknown. The following analysis assumes no particular distribution among the possible outcome segments in set 200, but only that the distribution is constant regardless of where the wheel 10 is stopped. That is, i.e., if the ball 150, on average, constantly ends up in the left segment 30% of the time, the bottom segment 60% of the time, and the right segment 10% of the time, this is true regardless of where 520 the wheel 10 is stopped at the bottom 50 (that is, regardless of which set 200 is placed at the bottom 50). This assumption is reasonable provided the wheel 10 is slowed and stopped at the same rate every trial.
Without loss of generality, a probability L (or R) to the ball 150 ending in the Left (or Right) segment can be assigned. Hence, the probability of the ball 150 ending in the bottom segment B is 1−L−R. Also without loss of generality, we assume a probability distribution p, which is a function of individual segments n. The expected value (EV) that a player expects to receive over all play of the game, as a function of the values Vn of the segments 100 and probabilities pn of the Value Vn stopping on the bottom 50, is as follows:
EV=Σpn{LVL+RVR+(1−L−R)Vn} (FORMULA 9)
Where the summation is over the segments n from n=1 to N,
VL=V(n−1)mod N and VR=V(n+1)mod N. (FORMULA 10)
Note that V0 is the same as Vn, since the wheel 10 is continuous.
Now, in Formula 9 there are two unknowns (L and R), so to find local minima/maxima, a partial derivative is needed:
∂EV/∂L=Σpn(VL−Vn) (FORMULA 11)
Clearly, the right-hand side of the above equation is a constant, hence either never zero or always zero, and similarly for the partial derivative with respect to R. So, the minimum/maximum EV is located at the boundaries of the range for L and R, i.e., the extrema of the plane in L, R, B space bounded by the points (L=1, R=0, B=0), (L=0, R=1, B=0), and (L=0, R=0, B=1). Put another way, the maximum and minimum values of the expected value EV, for the game of the present invention as constructed, can be determined by assuming the ball 150 either always falls into the left segment L, always fall into the bottom segment B, or always falls into the right segment R. That is, although the actual distribution of balls into the left, bottom, and right segments is unknown and presumably a mixture of the three segments, only these three pure (not mixed) possibilities need be considered to determine the minimum and maximum expected value EV of the game.
Although the above discussion was in terms of three possible outcome segments in set 200, the extension to any arbitrary number of outcome segments in set 200 is immediate and follows directly by extending the above formulae. For any game as described herein with a number of possible segments N, the extrema of the EV can be determined by considering only the cases in which the ball 150 falls 100% into each of the possible segments 200, as weighted for each stopping location.
By way of example, the table shown in
The differential EV values are useful for understanding how much of a difference the values Vn and probabilities pn are affecting the spread in expected value EV. In the table of
In practice, as shown above and continued here, the values Vn may be manipulated to achieve the desired result, by design. Note that in this example, the wheel 10 stops with the value of V=$250.00 on the bottom fully 10% of the time (Pbottom=0.1); this is more than twice the probability if each segment 100 were equally likely. This leads to increased player excitement. Considering that the ball 150 may end up as far as 3 segments from the bottom, when finally landing, the chance of the $250.00 award being possible (that is, the $250.00 segment is located either on the bottom or within 3 segments of the bottom position) is in excess of 31% under this design. The figure of “in excess of 31%” comes about by adding the probabilities in Column III for segments 2 though 8, equal to 31.5%. Similarly, there is a 34.5% chance of a $500 award being possible. Again, this adds to the player's excitement and fuels the notion that the game is fair in terms of value.
Although the example cited herein discusses a min/max EV within roughly 1% of the average EV, the design could have the min/max differ substantially, perhaps by 25% or more if desired. Too, with an equal weighting of probability per segment 100 (i.e., each segment 100 ending on the bottom is equally likely), the min/max EV will precisely equal the average, if desired.
It is to be expressly understood that under the teachings of the present invention, by assigning values V, one to each segment 100, assigning the probability of the value landing at a predetermined stop position such as the bottom 50, and controlling the possible resting outcome segments in set 200 for the ball, the maximum EV and the minimum EV can also be mathematically determined to provide for regulatory control over the spinning wheel 10 with the freely moving ball 150. In this manner, the casino, regulators and players can be confident of the expected value. It is to be understood that by varying the number of segments 100, varying the value assigned to each segment 100, controlling the probability of each segment 100 landing at the predetermined stop position and controlling the number of possible outcome segments in a set 200, the present invention provides a wide variety of dynamic mechanical wheel, with a freely bouncing ball, casino games. Finally, the above discussion is directed to the EV for the wheel based on the above geometric and mathematical considerations. The design of bonus games for underlying gaming machines wherein the frequency of occurrence of bonus game play and the expected return for play of the underlying game are mathematically worked into the above calculations to provide an overall expected return (or house advantage) for a casino game is taught in co-pending application U.S. patent application Ser. No. 372,560, filed Aug. 11, 1999 and published Apr. 18, 2002, Publication No. 20020043759 and is herein incorporated by reference.
f. Mechanical Wheel Casino Game of Chance:
The foregoing has been discussed in terms of the mechanical wheel 10 stopping at a desired random location such as bottom 50, thereafter allowing the ball 150 to come to rest, via free-motion, into one of the possible outcome segments in the randomly placed set 200 of the wheel 10, which is held steady.
In
From the player's playing perspective, the method of the present invention set forth in
The present invention set forth in
It is noted that as an alternate embodiment, once the ball 150 has effectively landed or nearly so, the present invention releases the wheel 10 and simply lets gravity slowly rotate the wheel 10 so that the now-landed ball 150 rotates downward with the wheel 10 and the settled-upon segment 100 moves to the bottom 50 of the wheel 10 at the end of the casino game. This may be preferred in some cases, e.g., for aesthetic reasons. In this embodiment, a stepper motor 500 with a free-spin mode is used, or a separate brake mechanism could be used with brake activation on shaft 502 during stepping, which is then released to effectuate free spin.
An alternate embodiment is to spin the wheel 10 under stepper control 500 while slowly, very slowly, spinning until the randomly selected possible outcome segment set 200 is at the bottom 50, and then to release the wheel 10 (before stopping the wheel 10) so that both the wheel 10 and ball 150 are mechanically free. When free spin mode is used, the computer 800 may need the identity of the segment 100 (or pin 20) resting at the bottom 50 to determine orientation, so that the wheel 10 can be stepped to the next desired predetermined orientation.
This embodiment is set forth in
g. Wheel 10 Having Free Motion:
It is also possible to drive 510 the wheel 10 at a constant rate of speed for a predetermined number of revolutions, and release the wheel 10 to free motion, i.e., not controlling its stopping location 520. In this case, the calculation would assume that each segment 100 is equally likely to be stopped on. While this has advantages in terms of more closely mimicking the California Lottery THE BIG SPIN game, it makes each segment 100 equally likely and hence limits the designer's ability, in principle, to have some segments 100 of the wheel 10 worth extreme values while maintaining a moderate overall expected value. In this case, the ability to proactively monitor the outcome, by number of outcomes for each segment 100 number, is important also to contain bias.
In
h. Determining Ball 150 Position:
To determine the final resting segment 100 of the ball 150, one method is to use an optical reader. As shown in
As an alternative, when the wheel 10 is released with the settled ball 150, the ball 150 will end at the bottom 50. So it is possible to simply check (or monitor) which wheel segment 100 is at the bottom 50, and this will be the value.
i. Tracking Results:
While the invention disclosed herein, through mathematical and geometric means, limits the effects of potential bias in a mechanical apparatus, it is nevertheless useful in principle to make use of data regarding performance. United States gaming regulations strictly prohibit machines from proactively adjusting, e.g., probabilities, to get to a target hold percentage based on self-monitoring macro-variables such as coin-in and coin-out. However, a U.S. machine simply monitoring aspects of performance (such as coin-in and coin-out) is allowed. Other foreign jurisdictions may or may not allow self-monitoring.
With the popularity of mechanical bonuses, the main direction taken in development has been to predetermine their outcome such as through stepper motor control. In this case, the player is deprived of a casino game of chance with free-motion. The machine immediately tilts (voiding the game) if the mechanical apparatus does not end up in the predetermined configuration. So no need exists to monitor the mechanical performance in such casino games of chance.
A secondary direction has been to use mathematical methods to eliminate mechanical bias, so that a free-motion game may ensue (as discussed above for Pachinko). In this case, since mechanical bias is completely eliminated by the mathematical algorithm, no need exists to monitor the mechanical performance.
What has been described herein is a third possibility, one in which free-motion is employed and mechanical bias, although not eliminated completely, is carefully controlled. In cases like this, it would be beneficial as an added precaution, or perhaps to accommodate gaming regulators, to automatically track results—first, to compare results versus assumptions, and second, to compare actual results versus theoretical results—in each case to ensure that no mechanical bias or perhaps only an acceptable mechanical bias has crept in. What is taught in the following is not limited to the example of the mechanical wheel discussed above, but has application to tracking the performance of any casino gaming machine using a mechanical game play device.
For the prototypical example of a wheel 10 with 22 segments 100 and seven possible outcome segments in a set 200 per spin set forth above, several aspects of actual play verification may be addressed. These aspects may include: (1) that the expected value of the casino game of chance is within the theoretical limits, (2) that the distribution of occurrences by segment 100 is within the theoretical limits, and (3) that, per stopping position, the distribution of occurrences by segment 100 about the seven possible outcome segments 200 is uniform compared to other stopping positions.
What is collected and stored in a database is discussed in the following for each operation of the wheel 10 (i.e., completion of play to the ball landing).
Assume, the bottom segment 210 is stopped on. In this case the wheel 10 is run off a stepper motor 500 and, based on the stepper orientation, the wheel 10 location is automatically known. This is conventional in the gaming industry. Or, as an alternate design (such as the freely spinning wheel 10 in the above alternate embodiment) or in a verification design, in
The final segment 100 that ball 150 landed in relative to the bottom 50, as set forth in
In
To test this assumption, we may first sum the total number in the left, bottom, and right. We find # left (L)=194, # bottom (B)=494, # right (R)=312 for 1000 (total) operations. Using the resulting probabilities L=0.194, B=0.494, and R=0.312 as the expected (or norm), we may determine if any of the individual segments 100 are outside (say, +/−3 sigma or greater) that expected. By way of example, consider the L case. Multiply the L value of 0.194 by the TOTAL for each wheel segment 100 to get the number expected for the left segment 100, obtaining what is shown in
The test could comprise a comparison of the “# left L (actual)” column with the “# left L (expected)” column, measured in units of standard deviation, or SD, column. For example, for n=6 (the sixth segment on the bottom), then the Difference in SD is (34−44.6)÷6.7=−1.6. This is represented as the Difference in SD column. In a rudimentary form, the statistical check is simply whether any of the “Difference in SD” column entries has an absolute value greater than 3 (i.e., +/−3 sigma or greater) and if so, the detection of a problem and accompanying “tilt” or error message is indicated.
While we have described one test which might be done to ensure and/or control bias, other statistical tests are possible. It is possible for the expected values to be determined in advance, by trials conducted by the developer or manufacturer.
In
j. System:
In
The random number generator 810 and the processor 800 and the database 820 are conventional in gaming devices and could also be used to actually run the underlying game 1010 and the top box bonus game 1000 of a casino game 1020 (as shown in
There are several methods available to make use of this information. First, the data may be collected and stored in-machine such as in database 820, retrievable by a slot mechanic, e.g., via data port or wireless “wand” technology through output 830. Alternately, the data may be transferred via the Internet and/or phone lines 834 to a control center to be analyzed. Alternately, the data may be analyzed in-machine prior to retrieval and/or transfer. Finally, the machine may analyze the data internally and go into a “tilt” or other special mode if a problem is detected by activating a tilt alarm 840 over lines 842. It is important to note that the machine, in this case, is monitoring its own mechanical performance, and not violating any regulatory statutes.
k. Method:
In
As mentioned in the verification embodiment, when the wheel 10 is moved to its predetermined location in step 910 (or when the wheel 10 is freely spun), in step 940 and as shown in
In
The above disclosure sets forth a number of embodiments of the present invention described in detail with respect to the accompanying drawings. Those skilled in this art will appreciate that various changes, modifications, other structural arrangements, and other embodiments could be practiced under the teachings of the present invention without departing from the scope of this invention as set forth in the following claims.
This non-provisional patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/586,115 filed on Jul. 7, 2004 entitled “Wheel for Internal Indicator and Controlled Expected Value for Casino Game.”
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