Design And Experimental Study Of Small-sized Ice-cream Vending Machine

With the maturity of automatic control and mobile payment technology and the growth of GDP per capita,people's pursuit of quality of life is increasing.China's vending machine market has entered the rapid growth period,and vending machines for fresh food products have quickly occupied market.Ice-cream vending machines are relatively slow to develop because of the high requirements for refrigeration temperature.Existing products can't meet the new market demand.Due to the increase in the rent of the site,effectively reducing the initial investment and operating costs is the key of market competition.Ice-cream vending machines will tend to be smaller,smarter and more energy efficient.The design of ice-cream vending machines is mainly focused on miniaturization.Miniaturization reduces the cost of delivery,the heat load of the refrigeration system and the power consumption required for air supply.The existing vending machines'shipment method has a large limitation on the height and the thickness.It's necessary to design a reasonable shipping method which can realize a compact structure and organically combine with the refrigeration system.In this paper,the design and experimental research of miniaturized ice-cream vending machines were carried out for the design requirements of miniaturization:1)According to the market demand of miniaturization,the whole machine structure design,refrigeration system design and control system design of ice-cream vending machine were carried out.A design scheme of miniaturized ice-cream vending machine is proposed.The long-range multi-layer shelf and the short-range multi-degree-of-freedom robot are used to achieve a compact design that matches the refrigeration system.The size of the machine meets the wall hanging requirements and thickness is only 380mm.With a volume of 0.38m~3,it's one-fifth the size of a common ice-cream vending machine.The system design work is carried out for the whole structure,automation action,control system and refrigeration system.The design and calculation of the refrigeration system provide theoretical support for the feasibility of the refrigeration system,and also provide for the selection of various components of the refrigeration system.2)An ice-cream vending machine experiment system was built and automatic shipping operations were implemented.The ice-cream vending machine experiment system was built according to the design scheme,and the error of the measurement system was checked.Automatic control of design shipment actions has been achieved.The waiting time for mid-layer ice-cream purchase is 35s,and the upper and lower layers are 53s.The waiting time is relatively long,the main reason is that the action steps are too much and the long-distance uniform motion takes a large proportion.According to the movement time in the Z-axis direction can be reduced in the middle layer,the ice-cream should be arranged according to the sales volume to reduce expectation of the purchase waiting time.Comparing the ratio of the motion time to length of the same type motor,the response delay of the motion conversion in the control system is calculated to be 0.2s.In view of the existing shipping actions,an optimization scheme for integrating the shipping lines,reducing the number of actions and controlling the non-uniform motion of the long-range motion is proposed.3)The refrigeration system was regulated to determine the optimal refrigerant charge.Running the entire experiment system,the optimal arrangement of the evaporator was proposed by analyzing the temperature field in the storage room and the problems of system matching were solved initially.In the experiment of refrigeration system,evaporator inlet and outlet temperatures and storage chamber temperature are measured.Analysis of these temperatures determines that the optimal refrigerant charge of the system is about 135g.Running the entire experiment system,analyze the temperature field in the storage room to propose the best solution for the evaporator and the fan to be arranged above the rear side wall of the shelf.The storage temperature of all ice-cream can reach about-21?.The replenishment simulation experiment monitors the temperature change process of replenishment and rewarming.The replenishment time should be controlled within1min to ensure the storage temperature below-18?.In the simulation experiment of the shipping action,the effect of low temperature on the sensitivity of the photoelectric sensors is found.Reserve a 10mm stroke for the ice-cream loading action by increasing the sensitivity to achieve the same positioning effect as at room temperature.