Common washing machine controller has single function, easy to damage and inaccurate timing. With the development of modern science and technology and the improvement of management level, ordinary washing machines can not meet people’s requirements. This design is to use the principle of fuzzy control to automate the transformation of the ordinary washing machine controller, so that the ordinary washing machine has intelligent control function, improve the quality of laundry, save energy.
Washing clothes has always been a hard work to avoid. In 1858, the world’s first washing machine came out. In 1874, the world’s first artificial stirring washing machine appeared. In 1911, the first electric washing machine was invented successfully. Especially in 1932, an American company developed the first front-mounted drum automatic washing machine, which made the development of washing machine leap to a new stage. After World War II, washing machines developed rapidly. In recent decades, in developed industrial countries, the manufacturing technology of automatic washing machine has developed rapidly, and its annual total output and social popularity have reached a fairly high level. Most of the traditional washing machine controllers adopt winding mechanical control with single function, easy damage, inaccurate timing and so on.
The real automatic washing machine is a controller made of single chip computer, which has accurate timing, eye-catching time display, and can control the washing of various clothes flexibly according to the requirements. Compared with the traditional washing machine, the automatic washing machine has the following specific changes: First, the washing method has changed from the former one which mostly focused on the change of water flow and the increase of power to the present one which uses ultrasonic wave, electrolytic water, ozone and steam washing, so that the detergency ability of the washing machine can be changed from relying solely on the chemical action of detergent and the fast flow of water. Slow effect to health, environmental protection washing mode change. Secondly, the washing machine is highly automated, intelligent and humane. From semi-automatic and fully automatic to artificial intelligence and fuzzy control. Thirdly, the more humanized design is more convenient and comfortable to use, such as taking clothes without bending; automatically washing different clothes separately; with steam drying function and lower noise.
Finally, the capacity of washing machine is also increasing, which is in line with the future consumption trend. The reason why the automatic washing machine can imitate human intelligence is mainly to collect various information and data by a variety of sensors. For example, there are turbidity sensors that automatically perceive the dirty degree of clothes, so as to determine the amount of laundry powder put in; there are water level sensors that automatically perceive the level of water level, so as to determine the amount of water in laundry. The sensor will input all kinds of information and data collected by sensation into the fuzzy control chip for comprehensive processing and judgment, then issue instructions, command the washing machine to automatically select the corresponding washing procedures, and adjust them accordingly according to the changing factors in the laundry at any time, so as to achieve the best washing effect. The core of the automatic washing machine is the MCU control board, which has the function of detection and control. Detection function refers to the detection of clothing quantity, clothing quality, dirty degree, dirty property and other indicators through a series of sensors; control function refers to the determination of washing water level, water flow mode, detergent dosage and washing time based on the detected information. The key to design an automatic washing machine is how to determine the washing mode according to the detected indicators. Because the control object of laundry process is difficult to be described by precise mathematical model, it is difficult to achieve ideal laundry effect by traditional control method. But the fuzzy control method can solve this problem well, because this method has the characteristics of no need to establish accurate model, easy to implement and consistent with human thinking mode. It provides an effective way for the realization of the automatic function of washing machine.
Compared with traditional control theory, fuzzy control has two advantages: first, in many applications, fuzzy control can effectively and conveniently realize human control strategy and experience, which has been closely concerned since the birth of fuzzy control. Secondly, the fuzzy control can achieve better control without the mathematical model of the controlled object, because the dynamic characteristics of the controlled object are implicit in the input and output fuzzy sets and fuzzy rules of the fuzzy controller. This design is a controller of automatic washing machine. It mainly uses single chip computer. The inference parameter signals sent by water level sensor and turbidity sensor are sent to the input port of the controller. The controller determines the water inflow and washing time according to the fuzzy inference rules.
MCU output corresponding display signal and drive signal, which is the core part of the whole system. By choosing 89C51 single-chip computer, all the requirements of the design task book can be realized. The software of this single-chip computer has a large degree of Programming Freedom and can be programmed to realize various control algorithms and logical control. It has a complete bit-by-bit operating system from the internal hardware to the software, called a bit processor. Its object of processing is not words or bytes, but bits. It can not only process some bits of some special function registers on chip, such as transmission, placement, zero clearing, testing, etc., but also carry out bit logic operation. Its function is very complete. It has multiplication and division instructions, thermostatic element which also brings convenience to programming. This design is a controller of automatic washing machine. It mainly uses single chip computer. The inference parameter signals sent by water level sensor and turbidity sensor are sent to the input port of the controller.
The controller determines the water inflow and washing time according to the fuzzy inference rules. There are two kinds of displays: LED and LCD. LCD is a liquid crystal display, which is a passive display, that is, the liquid crystal itself does not emit light, but uses the characteristics of the liquid crystal after treatment to change the direction of light through, so as to achieve the purpose of white-background black-character or black-background white-character display. The motor drive is controlled by bidirectional PWM pulse width modulation. By using this control method, the positive and negative rotation and speed change of the motor can be easily realized through the mutual change of the high and low levels of the two ports. Resonant water level sensor adopts a new sensing principle to detect the water level, which directly transforms the water level into the corresponding relationship between water level and frequency through the water level sensor. The detergency, water flow intensity and washing time of clothes play a decisive role in saving water, saving energy and reducing washing time of fuzzy control washing machine. The turbidity sensor is installed on the outlet pipe near the upper end of the drainage valve. The main principle of turbidity detection sensor is optoelectronic coupler, but ordinary optoelectronic coupler can not effectively detect the turbidity of washing machine water. The optical source of the optocoupler must be infrared light in order to detect turbidity accurately. In this hardware circuit, we need a DC power supply system with stable voltage. This system converts 220V AC voltage to 5V voltage. In low power rectifier circuit (below 1 kW), several common rectifier circuits are single-phase half-wave, full-wave, bridge and double-voltage rectifier circuit.
Here is a one-way bridge rectifier circuit. The task of rectifier circuit is to convert alternating current into direct current. The main way to accomplish this task is the unidirectional electric action of the diode, so the diode is the key component of the rectifier circuit. The filter circuit is used to filter the ripple in the output voltage of rectifier. It is generally composed of reactance elements, such as shunt capacitor C at both ends of load resistance, series inductor on load, and various complex filter circuits composed of capacitors and inductors. The shunt capacitor C at both ends of the load is selected here. The design is divided into modules, consisting of a main program and several subroutines.
Real automatic washing machine has many functions and many complicated subroutines, such as display subroutine, keyboard scanning subroutine, program setting subroutine, washing mode selection subroutine, water volume setting subroutine, time setting subroutine, self-checking subroutine, detection subroutine, temperature detection subroutine, water intake subroutine process.
Water level detection subroutine, turbidity detection subroutine, motor operation subroutine, washing subroutine flow, dehydration subroutine, drainage subroutine and so on. This design only describes the main program flow chart and the sub-program flow chart of some main module modules and their codes.