An overwhelming problem with the United States population, specifically children, is health and obesity. A key nutrient in the growth and development of children is calcium. Many children, however, do not like plain milk, so parents are forced to resort to feeding their children processed, sugary chocolate milk. Some parents are able to bypass this processed sugary drink, and make chocolate milk on their own simply with milk and a healthier, low sugar chocolate syrup. The issue with homemade chocolate milk is that there is always too much chocolate syrup, and the syrup sinks, or there is too little and it is not “chocolaty” enough. In order to help create an evenly mixed drink, self-stirring chocolate milk mugs have been created, but they do not prevent errors in the amount of chocolate syrup added. By creating a chocolate milk mug that senses the concentration of chocolate in the milk, and reacts accordingly to optimize the chocolate concentration, healthier and more delicious chocolate milk can be made.
The control of the concentration of chocolate milk can be justified due to the increased health benefits from healthier and less processed chocolate syrup. Additionally, by controlling the concentration of chocolate, it prevents the overuse of chocolate syrup, therefore reducing the cost to the consumer.
As the amount of chocolate syrup added by hand never seems to come out right, the homemade production of chocolate milk must be optimized. It also needs to be optimized because chocolate syrup costs an average of three dollars for 24 oz. If chocolate syrup is not measured when it is added to the milk, too much could be detrimental to your pocket. Those couple of cents adds up for the extra syrup that you do not need. Optimizing the amount of chocolate that is put into the milk will save money by reducing the amount of premade chocolate milk purchased and also by not wasting unnecessary syrup. Another reason why consumers benefit from optimizing the amount of syrup inside the milk is because making your own chocolate milk can be healthier than drinking the processed, pre-mixed brands.
The first step in starting the process of making the best chocolate milk is to identify the variables that are being affected. The control variable for this system will be the concentration via the density of the milk, which will be monitored using a sensor. This sensor measures the density throughout the mixing process, but we are mostly concerned with what the concentration is after the mixing has completed. Since the sensor measures the density of the chocolate milk, it is important to determine what the optimal measurement is. This was determined by creating different concentrations within a certain amount of milk. After a taste test of each, it was determined that the optimal density of chocolate milk is 0.219 g/mL. Because there is bound to be some slight error, the acceptable parameters for the density of homemade chocolate milk is within 10%, or 0.196 g/mL to 0.239 g/mL. Although the control of the concentration of chocolate milk is not critical to the function of the mug, it is quite beneficial to the consumer and our purpose is to always please the customer. The manipulated variable is the amount of chocolate syrup in the milk. This is the manipulated variable because it can be controlled in order to make the best chocolate milk. This is the most practical variable to manipulate because it is what makes the milk taste delicious.
The variables that could potentially disturb the way our system works could include the amount of milk that is placed into the mug, the brand of chocolate syrup, and the type of milk. Different gradients of milk have different densities so the optimal density would need to be adjusted. The chocolate syrup, too, can differ depending on the brand as each brand of chocolate syrup has a slightly different concentration and density of chocolate taste. While the Skinny Moo Mug is extremely reliable, it can under perform at times. Although the chocolate milk could suffer minor quality deficiencies due to disturbance variables, the consumer can be at ease because these disturbance variables should be accounted for in the density readings taken by the concentration sensor. It is recommended that if errors in the chocolate milk taste occur, a spoon be used to ensure complete mixing. In order to tell if any of these disturbances have affected the delectable, scrumptious taste of chocolate milk, a feedback loop would be appropriate. A feedback loop is best because the system is reactive. In other words, the system does not change the amount, or density, of chocolate milk until an error arises. Additionally, a feedback loop provides an explicit response where the density of the chocolate milk can be changed to a predetermined explicit value.
In order to create the optimal chocolate milk, we will be constructing a variation of the “Skinny Moo Mug.” As seen in the YouTube video below, built into the mug is a spinner to ensure equal mixing of the chocolate syrup.
https://www.youtube.com/watch?v=xlX4Tyq-ShY
Instead of the standard cap seen in the stock photo, we will be using a patented cap that has an automatic opening and closing flow hole at the bottom. Instead of leaving the whole cap as an open space, we will create a wall on the ledge labeled 14E in the photo below. Creating a wall will ensure that one does not drink solely chocolate syrup when they take a sip of refreshing chocolate milk. Additionally, a hole will be made on the surface labeled 12D in order to allow for one to actually drink out of the mug. The original opening shown in the picture as G, will be used as the opening to the reservoir to add the chocolate syrup. In order to automatically open and close the flow hole labeled 14A, the cap needs to be connected to a concentration sensor.
As the cap already comes with the potential to be connected to a sensor, the only task is to insert our own sensor. The sensor that will be used is called the Microelectromechanical Systems (MEMS) Liquid Density Sensor from Integrated Sensing Systems (as seen on page 5 of http://metersolution.com/wp-content/uploads/2014/08/Micro-liquid-density-sensor-User-Manual-1-1-1-1.pdf). As seen in the photo, the sensor is smaller than a dime, and will be mounted on the side of the wall of the mug. As the liquid is mixed and flows throughout the mug, the chocolate milk flows through the sensor. The sensor will read the density, and therefore concentration of the concentration of the chocolate milk. The MEMS sensor will be pre-programmed to transmit the density data to the receiver that is already in the cap. The receiver will also be pre-programmed to either open or close the flow hole depending on the density sent to the receiver. The mug with the patented cap and density sensor will make for the most delicious, optimal chocolate milk.
References:
http://www.google.com/patents/US8678220
https://www.youtube.com/watch?v=xlX4Tyq-ShY
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I’m impressed by the novel chocolate milk control system. Optimizing the concentration of chocolate milk can provide healthier and more delicious chocolate milk, which is really helpful in our daily life. Speaking from my own experience, it’s hard to control the amount of syrup added into milk to get my desired taste. It’s easy for me to add too much and as a result the chocolate milk is too sweet to drink, so such an advanced design will definitely help me a lot. Besides, I think this control system can be analog to other mixing processes such as optimizing the amount of milk added into a cup of coffee. There are some similarities in those cases and the ideal of controlling the concentrations in those products would be appreciated by the general public. But one of my concern is about the price. The prices of a simple mug and materials to make chocolate milk should be cheap, but adding a feedback loop into the Skinny Moo Mug will definitely increase the price of the advanced Mug. I’m not sure whether the general public would like to buy the product if the price is higher than their expectations.
I agree with de defined controlled variable and those disturbance variables but I’m doubt on the manipulated variable, the amount of syrup added into the milk. All the statements made in the article are based on the assumption that no underdamp happened in the control system, so that the actual concentration of the chocolate milk is always lower than its set point and it needs to consistently add syrup into milk. But what if too much syrup is added? It’s impossible to take extra syrup out since it has been mixed with milk. In this case, there should be another manipulated variable, the amount of milk in the system. If the actual concentration of the chocolate milk is higher than the desired concentration, milk should be added to dilute the dink. The potential existence of extra syrup in the chocolate milk reveals another potential issue when commercializing this product. If the several dilutions are needed, more and more amount of milk will be used. Is the size of the container, the advanced Skinny Moo Mug, big enough to allow such large amount of milk being added? Also, the Mug should not be too big to carry.
A PI controller may be appropriated in the control system. As mentioned, overshoot should be avoided in this process and it doesn’t require very fast response. Although PI controller still may introduce overshoot, it can eliminate the offset caused by proportional controller. As a result, it would be an appropriate choice for developer. The controller parameter can be calculated by using the developed methods for a closed loop.
This product would allow users to have premade quality chocolate milk at home without paying the additional price for chocolate milk compared to regular milk. Additionally, it will drastically simplify the process of making chocolate milk. It eliminates human stirring and also the guess and test method that most people use for adding chocolate syrup. This saves time when trying to prepare homemade chocolate milk. For this reason, I can see this product becoming popular especially among parents of kids who guzzle chocolate milk by the gallon. Furthermore, I think this product could be popular among people who like to grab breakfast on the go.
Based on the current design parameters, I think this product would be incredibly effective at regulating the density of the milk. The sensor that they have chosen to use already exists and can effectively measure the density. Additionally the patented cap they plan to use can be opened or closed to allow chocolate syrup to flow through. The type of milk could be the disturbance variable that is the hardest to control. The relative densities between skim milk and whole milk differ by a much larger extent than concentrated and dilute chocolate milk. Therefore, skim milk would end up being much more chocolaty than whole milk. In order to reduce this effect a user input could be added. This user input would allow the user to select their desired density. This would also be beneficial since not every user prefers the same concentration of chocolate syrup in their chocolate milk. Making the user input a density could be very complex. To alleviate this the mug could have the user input be a “chocolate index” on a scale from 1-10 and each one of those values would relate to a different density set points. Then all the user would have to remember is their different favorite chocolate index for different types of milk.
In order to tune this device I think a PI controller should be used. A proportionally controller on its own will never reach the set point so it should be used in conjunction with an integral controller. However, a derivate controller seems slightly unnecessary for this system. A derivate controller is good to see where you are going. However, in a system where there is relatively little change this aspect seems highly unnecessary. Therefore, a simple PI controller would be sufficient for this system.
Overall, I think that this is a very interesting and new idea. I can definitely see people using this mug to make the best chocolate milk. I, for one, like my chocolate milk very chocolaty, so I always end up with chocolate settling on the bottom going to waste. Additionally, this process could be used for other drinks and mixes, such as powder iced teas, which I can never get right. Lastly, this will make the process of making these drink much faster because there will be no need for stirring or tasting and adding a bit more of either ingredient. The operator will just have to add the ingredients and it will be done perfectly the first time.
I believe that the variable discussed were all very valid and made sense for the process. I am just curious how the system will handle the various types of milk and syrup. Will the operator need to input the product before use to ensure the proper density is achieved? Whole milk had a much higher density than skim milk, and you would not want the whole milk to end up less chocolaty than the skim milk when using the product. Additionally, would it be possible to determine how chocolaty one desires their milk to be, because not everyone likes the same amount of chocolate. I also wonder what happens if too much chocolate is added. The way the process is set up now, there is no way to fix this overshoot. Maybe it is necessary to have a second manipulated variable that can add milk if the drink becomes to chocolaty.
When tuning this device, a PI controller should be used. A plain proportional controller will never reach to optimal chocolate strength, so it must be used with an integral controller. Because the system only has one input that can only be added and not subtracted overshoot cannot occur. With any overshoot the milk will have too much chocolate and nothing can fix that. I do not think that a derivative controller is needed for this process, so I would recommend just a PI controller.
Every time I have ever made chocolate milk, I ran into exactly the problems you mentioned: I either added too much or too little chocolate, or the chocolate clumped at the bottom and the top was lacking. I think your control is one that will not only benefit me, but also will benefit households across the nation! Not only will it improve the quality of the beverage, but, as you mentioned, it will also be (slightly) healthier and save money.
Controlling the density of the milk using a feedback loop definitely makes sense; however, I agree that the initial milk or chocolate used could become a problem. Therefore, it may make sense to have multiple settings with different set points. To the user, this could be as simple as labeling a dial “Whole Milk,” but the controls could factor in what the density should be based on this type of milk. This will at least account for the density in whole, x%, or skim milks. Alternatively, a color sensor may help resolve this issue. A sensor that could stop chocolate flow once the particular shade of brown is reached could aid in the accuracy of the taste between different milk types, assuming the same kind of chocolate is used each time.
One question I have is how you intend on stopping the flow of chocolate into the cup. A continuous process would make the most sense, given there is a sensor, and this process would necessarily be overdamped, as chocolate could not be removed once it is added to the cup. Therefore, chocolate flow must be stopped immediately once the desired density/color is achieved. I understand that your cap would do this, but what about the chocolate that remains on the cap. Is it wasted? Do you never wash the device and save it for later? I suggest attaching the chocolate syrup bottle directly to the cap and close the bottle once the desired set point is reached.
A P (proportional) controller would be best; however, the set point should be higher than the desired output. A proportional controller will allow for a steady increase in the density (or color), but will not reach the desired set point, rather, it will stay right below. Therefore, by making the set point higher than desired, the system can precisely reach the desired set point. Adding the integral control (PI) could be used instead of programming higher; however, this quick response will cause an overshoot, which cannot be removed from the system once added. Finally, adding derivative control will quickly jump to the set point; however, the PID controller is unnecessarily complicated (and therefore expensive) for this type of application. Therefore, I would recommend solely using a proportional controller, especially since an overshoot cannot be mediated regardless of the disturbance introduced. Developers could develop control parameters for this through trial and error to determine the actual set point as compared to the desired one, as the difference between the two must be known.
The designs of the chocolate milk mixer are very thoughtful and user-friendly. However, from a user standpoint, I will not buy this product nor suggest anyone to buy it. Firstly, an installed feedback control loop increases the price of this product. Secondly, there is not an optimal taste of a chocolate milk. Different people have different taste. Even the taste of the same person changes. One day I might want a lighter chocolate milk, but another day I would like to have a thicker one. Thirdly, this product can only be used in making chocolate milk. I would prefer a cup simply with an automatic mixer which cost me less and can not only make multiple types of drinks for me.
The control variable for this system is the concentration of the milk. The manipulated variable is the amount of chocolate syrup in the milk. The disturbance variables are the amount of milk, the brand of chocolate syrup and the type of milk. Different types of milk might be an issue where the setpoint of density cannot accurately represent the taste of the milk. For instance, the skimmed milk has lower densities. When it is added into the mug, in order to achieve the setpoint density, the chocolate syrup will be added more than it should, resulting an undesired amount of syrup added and also the taste.
A feedback loop is appropriate for this system since it provides a reactive process and an explicit response. As for the controller action, it is appropriate to use a PI control. A simply proportional control will lead to an offset so it can not be used. An overshoot is unwanted here since that once too much chocolate syrup is added, the high concentration is irreversible since the milk amount is constant. Although a PI control sometimes introduces an overshoot, it can be tuned to minimize the overshoot. Moreover, the overshoot always happens at the start of the control. After a certain amount of time, this overshoot can be compensated. A derivative control is not necessary and might lead to an unstable process. In this system, the time response is not significant while the derivative control is mainly used to increase the time response. Due to the changing concentration and the imperfect mixing which are considered to be unstable and noisy conditions, the derivative control is not desired to be used here.
As one of the founding fathers of the Queso Roboto, I respect and applaud the work behind this blog post. People often tend to overlook the tragedies that occur in the kitchen, and it’s up to engineers like us to rise up to these challenges. Though I myself am not a huge chocolate milk fan (I prefer the OG 2%), I can easily see the issue at the issue at hand and its dire consequences. Humanity as a society is imperfect, and it is to be expected that tasks like preparing chocolate milk can go awry and result in too much chocolate syrup wasted. This could further lead to a loss of money and a loss of happiness.
The application proposed by this article makes perfect sense and would be extremely beneficial to society. Chocolate milk is regarded as a childhood staple, and adding the perfect amount of syrup is crucial in order to not overfeed our children too much sugar. By using the density sensor, the concentration of syrup in the milk can be analyzed, and the proper amount of syrup can be dispensed by the cup lid. I love the whimsical idea of the product, but feel like the authors should be more explicit as to how this device would work and look.
The control aspect of this makes sense. The density sensor would most likely not get a perfect reading of the sample as a whole, but its estimate would most likely be good enough for our purposes. The selected manipulated and controlled variables are straight forward and are well considered with the controller proposition. I’m glad that proper experimentation was performed in order to find the perfect chocolate milk density. The disturbance variables of quality control and different chocolate syrup brands are valid concerns, but I am not sure how much of an effect these variables would have on the density of the solution.
A closed loop system is essential to this controller due to the need for a feedback system. There is currently no at-home system readily available that could calculate the optimal chocolate concentration in a chocolate milk solution. One recommendation I have is that the operator could calibrate the controller to a density of their choice. Different people like different degrees of chocolate, and allowing them to set their own concentration could make increase product versatility and customer satisfaction. To make this process simpler, different, pre-set concentration settings can be implanted, such as “Chocolaty”, “Extra Chocolaty”, and “Super Duper Extra Chocolaty”. Overall I think that this is an excellent process controller and could really make a difference in the world.