Design of smart home lighting control system based on artificial immune system and ZigBee (Part 1)

1 Introduction

The role of smart home lighting control is not only to create a good light environment, but also to save energy. Therefore, a good lighting control system should be able to make full use of natural light from the outside and dynamically control lamps to achieve the best effect with minimal energy consumption. Most of the existing smart home lighting control systems only meet the different needs of users by presetting multiple modes and using users to switch between different modes. Once the illumination of the surrounding environment changes, this type of system cannot adjust adaptively and will still maintain the preset illumination. In fact, these lighting control systems cannot be called smart home lighting control systems in the true sense.

Living organisms are constantly attacked by various antigens. The biological immune system can identify self-antigens and foreign antigens, and eliminate antigenic foreign bodies through immune response to maintain the physiological balance of the body [1]. Artificial immune system is a means and method developed by learning from and utilizing the information processing mechanism of the biological immune system to solve various engineering problems [2]. If the ever-changing natural light and user needs are compared to antigens, and the real-time illumination of related lamps that meet user needs is compared to antibodies, the composition structure and function of the smart home lighting control system are very similar to the biological immune system.

The system designed in this paper is a new type of smart home lighting control system. It simulates the biological immune system, uses the relevant knowledge of the artificial immune system, and dynamically controls the lamps through the continuous matching of antibodies and antigens, so as to achieve the purpose of adaptively meeting user needs in the ever-changing natural light environment. This paper uses ZigBee wireless communication technology to build a network, realizes the communication between each lamp, remote control and controller, and can intelligently control the lamps according to the different lighting needs of users, make full use of natural light, and achieve the best effect with the minimum energy consumption.

2 Overall system design

In the smart home lighting control system, the ZigBee wireless networking method with low cost, low power consumption and large network capacity [3] is selected. The control system consists of an immune controller, a lighting control terminal and a remote controller, following a unified network protocol. With the help of various "pre-setting" and "online setting" control methods, users can accurately set and reasonably manage the lighting brightness at different times and in different scenes, making full use of external natural light, extending the life of the lamps and saving energy consumption. The use of a smart home lighting control system not only achieves simple operation and convenient maintenance, but also meets the diverse requirements of work and life. The overall structure of the system is shown in Figure 1.

The immune controller is not only the network coordinator in the entire network, but also the central processing unit of the artificial immune system. It is responsible for tasks such as maintaining the system network, processing events, and storing data. The node contains a ZigBee RF transceiver module, an illuminance sensor, and an embedded control system. Each lamp control terminal is connected to the corresponding lamp. Its main function is to receive instructions from the immune controller, control the lamp operation, and adjust the light brightness. The node is mainly composed of a control circuit and a ZigBee RF transceiver module. The remote control can realize mobile control and is mainly composed of a ZigBee RF transceiver module and an embedded control system. The ZigBee wireless network is composed of a star topology. The immune controller serves as a network coordinator, and each lamp control terminal and remote control serve as terminal devices. Users can issue instructions such as switching and dimming of each lamp by controlling the remote control. They can edit scenes according to their own needs and the natural light illumination at the time, and can select their own preset scenes at any time. The immune controller receives the instructions issued by the remote control and uses the artificial immune system to select the scene that best meets the user's requirements according to the current natural light illumination. Each lamp control terminal receives the control information sent by the immune controller through the ZigBee network, and controls the lamp to perform corresponding operations through the control circuit.

3 Structure and function of immune controller

The structure of the immune controller is shown in Figure 2. It mainly consists of three parts: central processing unit, immune response area and bone marrow. The central processing unit, as an interface for exchanging information with other parts of the system, is mainly responsible for receiving information from the remote control and illumination sensor and using the information to generate antigens. It also translates the output antibodies of the immune response area into instructions and sends them to each lamp control terminal. The bone marrow is responsible for producing B cells and making them meet the requirements of the immune response area, that is, the bone marrow only delivers mature B cells to the immune response area. The immune response area is the place where antigens and antibodies match. Through operations such as affinity-based selection, the optimal antibody is determined and transmitted to the central processing unit.

3.1 Antigen

A residence is a private space, mainly including a living room, dining room, kitchen, bathroom and bedroom. Different lighting designs should be adopted to meet the different usage functions of each space. Taking the living room as an example, it is a multifunctional activity space, and the lighting configured should be able to cooperate well with various activities in the family, such as watching TV, reading, gathering, etc. [4]. At the same time, the illumination of natural light outside is different at different times, and different users have different requirements for different scene modes. Therefore, the antigen includes four attributes: house type, user name, scene mode and natural light illumination. The antigen comes from two aspects. On the one hand, when the user switches the lighting mode, the antigen comes from the user command of the remote control. On the other hand, when the natural light illumination changes significantly, the system automatically generates an antigen containing the current natural light illumination so as to readjust the illumination of each lamp. The threshold of natural light illumination change is set by the user on the immune controller.

3.2 Antibodies

The structure of the antibody is similar to that proposed by Farmer and his colleagues in the literature [5]. As shown in Figure 3, it mainly consists of three parts: antibody determinant, illumination coding region and idiotype. The structure of antibody determinant and idiotype is similar to that of antigen, and also includes the same four attributes. The illumination coding region includes the optimized illumination of the relevant lamps in the current situation. These illuminations are recognized by the central processing unit and sent directly to the lamp control terminal for controlling the relevant lamps. Antibodies can recognize not only antigen determinants but also idiotypes of other antibodies through their antibody determinants, thus ensuring the diversity of antibodies.

3.3 B cells and bone marrow

B cells are the carriers of antibody molecules. This article does not distinguish between the two, and their structures are exactly the same. There is a memory B cell bank in the bone marrow. Various lighting modes set by different users under different natural light illumination are stored in the bank as memory B cells. Every time an antigen is input, the central processing unit transmits the first three attributes of the antigen to the bone marrow, and the bone marrow completes the matching of the first three attributes of the B cell with the first three attributes of the antigen. Only fully matched memory B cells can be expelled from the bone marrow as mature B cells, enter the immune response area, and become antibodies in the immune response area. The above process is the tolerance process of B cells. If the user modifies a lighting mode, a new B cell will be generated in the memory B cell bank, and B cells that are particularly similar to it will be eliminated. This ensures that the bone marrow can always remember the user's latest needs, while maintaining the diversity of memory B cells in the bank.

3.4 Central processing unit and immune response area

The central processing unit is an interface connected to the lighting control terminal, remote control and illumination sensor. It stores the measurement data from the illumination sensor and the user commands of the remote control, and sends instructions to each lighting control terminal. The central processing unit also controls the other two parts of the immune controller, the immune reaction area and the bone marrow, providing them with antigens in real time.

The immune response area is the core of the immune controller. Antibodies and antigens are matched here, and the optimal antibody that meets the user's needs is finally produced. The immune response area includes a large number of interactive functions that calculate the affinity between antigens and antibodies, and finally determine the optimal antibody and pass it to the central processing unit.