Sweeping robot program development and design
With the continuous development of technology, various new types of equipment continue to emerge to deal with, and sweeping robots also appear. Initially, intelligent sweeping robots were widely used in European and American countries. In recent years, with the development of the economy, the scope of use of intelligent sweeping robots in our country is also expanding. The so-called smart sweeping robot can also be called an automatic sweeper, a smart vacuum cleaner, a robot vacuum cleaner, etc., which are also an important part of current smart home appliances. It mainly uses artificial intelligence to automatically clean up the floor in the room. Intelligent sweeping robots mostly use the form of brushing and vacuuming. First, the debris on the ground is put into the garbage storage box through the suction of the machine, so as to clean the ground.
1. Functions and types of sweeping robots
The body of the intelligent sweeping robot is a wireless machine, which has a disc shape. With its own battery, the intelligent sweeping robot can be controlled by a remote control or control panel. Users can make an appointment for cleaning before use. The front section of the intelligent sweeping robot is equipped with sensors, which can quickly and accurately detect obstacles in front. The line of the intelligent sweeping robot has been set by the manufacturer, it can turn on its own when encountering obstacles, and carry out indoor cleaning work in a planned way.
At present, there are mainly the following types of intelligent sweeping robots: ①Single-mouth sweeping robots. This sweeping robot can effectively deal with the floating dust on the ground, but for those electrostatically adsorbed dust, the cleaning effect is not good. ②Mid-brush to clip-on sweeping robot. This kind of robot can effectively remove large particles, and the cleaning effect on blankets is also good, but the effect on the ground dust is not ideal. The cleaning of this kind of robot is mostly carried out by glue brushes and brushes. ③Lifting V-brush cleaning system, this system can better fit the ground, so as to well collect the electrostatic adsorption dust. Of course, the better the performance, the higher the price.
2. The technical principle of the intelligent sweeping robot solution
The reason why the home smart sweeping robot can work so conveniently, its working principle is as follows: the smart robot uses the infrared sensor principle for direction control, of course, some low-end robots also use ultrasonic bionic technology. In contrast, the cost of infrared sensing technology is low, but the application of this technology has higher environmental requirements. In other words, the feedback of this technology on light-colored objects is not flexible enough. In the process of long-term use, the infrared rays of the robot will also have a certain impact on the furniture in the house, and the furniture may fall off the paint. Ultrasonic bionic technology does not have these problems. The sensitivity of this technology is relatively high and it can effectively detect the position. However, the application cost of this technology is high, which also leads to the high price of the sweeping robot, which is difficult to circulate in the market. .
Generally speaking, the intelligent sweeping robot uses a microcomputer for system control. There are three cleaning brushes at the bottom of the sweeping robot, which mainly clean the house by rolling the area. Generally speaking, the body of the sweeping robot is relatively small, so it can flexibly pass through various areas, including areas that are difficult to clean, such as under the bed and under the sofa. The sweeping robot also has the function of intelligently avoiding obstacles. Once a collision occurs, the sweeping robot can generate memory to form an indoor map area. In the next cleaning process, the sweeping robot can remember the last map to prevent collisions again.
Under the new situation, intelligent sweeping robots have entered ordinary households. The intelligent sweeping robot can not only realize voice control, but also realize remote infrared control, giving users a more humane cleaning experience.
Third, the design ideas of the sweeping robot scheme
The sweeping robot can be divided into two parts: cleaning and charging according to the content of the completed tasks. Therefore, according to the hardware design concept, it should have two hardware parts: a mobile robot body with cleaning equipment and a charging device. Before the robot performs indoor cleaning tasks, it needs to use sensors to determine the general situation of the indoor environment and automatically plan its path. During the cleaning process, it needs to monitor obstacles and cleaning range in real time. When the power is lower than the set value, it needs to return to the charging device by itself, and Automatically receive charging, and the charging device is connected to the home 220V power supply to provide energy for the sweeping robot. According to the above analysis, the main hardware equipment required by the sweeping robot includes power supply, charging equipment, motor, mechanical structure, sensor equipment, etc. The hardware design scheme of the sweeping robot is as follows.
1. Power design
Any operation of any robot requires a continuous supply of energy, and the power supply system is the energy source for the sweeping robot and the basic guarantee for the normal operation of all other components of the hardware. The mobile working mode of the sweeping robot determines that its power system is basically powered by a rechargeable battery. The capacity of the battery is positively related to the cleaning time and power, and the frequent working mode of the sweeping robot also has a great effect on the number of charge and discharge of the battery and the service life. High demands. Choosing a suitable battery requires comprehensive consideration of factors such as weight, volume, capacity, charge and discharge current, and use environment.
In the battery selection of mobile robots, it is necessary to consider the actual working mode and characteristics of the robot, but also to take into account objective conditions such as cost and life. Ni-MH batteries have low cost, simple battery auxiliary circuits, and low environmental pollution, but they have disadvantages It is easy to produce a memory effect; the same problem also exists in lithium batteries; the lead-acid battery is too large, and it wastes too much space for the vacuum cleaner with a small body, which is obviously untimely. Lithium-ion batteries have specific advantages over other types of batteries. The first is the high energy density. The high specific energy battery such as lead-acid battery is only about 100Wh/kg, but the general lithium-ion battery can reach 600Wh/kg. The second is its high rated voltage. A single lithium-ion battery can reach a voltage of about 3.8V, far exceeding the 2V of a nickel-hydrogen battery. By building a lithium-ion battery pack, it can fully meet the power supply of the sweeping robot when multiple devices are running at the same time. supply. The third is that the temperature adaptability is very strong, and it can work normally between -20℃ and 60℃, while the indoor temperature of ordinary households is between 0℃ and 40℃, which fully meets the requirements; the fourth is that the lithium ion battery does not contain heavy metals And harmful substances, will not cause excessive harm in the process of use, scrapping and recycling. However, lithium-ion batteries have their own problems, such as active chemical properties and easy explosion, so you need to pay special attention when using them. Lithium-ion batteries are widely used in mobile electronic devices, such as mobile phones, notebook computers, and tablet computers. Therefore, considering the advantages of lithium-ion batteries, sweeping robots should choose this type of battery as a power source. Taking into account the actual work content and duration of the sweeping robot, six 1.2V 3 000mAh lithium-ion batteries are used.
2. Sweeper charging equipment
The charging device is also called the charging base in the system of the sweeping robot, which is similar to the charging pile for electric vehicles. Because the position of the charging device is fixed, the sweeping robot needs to be charged back and forth. Similar to most household appliances in the family, the charging base of the sweeping robot also adopts the voltage and current standard of 220V AC, and the charging equipment can obtain electricity from the ordinary wall plug, which is simple and convenient. The current required to charge the battery of the sweeping robot is low-voltage direct current, so it must go through processes such as step-down, rectification, and filtering in the middle.
If the charging device directly charges the battery without a reasonable voltage conversion, it is likely to cause irreversible damage to the battery, and even cause dangers such as combustion and explosion. This process can also be replaced by a conforming power adapter. In terms of charging form, it is currently divided into two main forms: wired charging and wireless charging. Wired charging is similar to the charging of ordinary electronic devices. When the sweeping robot reaches the charging cordon, it will automatically send an early warning. After the user finds it, connect it to the charging device via a cable in time. The advantage of wired charging is that the equipment is relatively simple, the cost is low, and the impact on the life of the battery is small. The disadvantage is that the operation is complicated. Wireless charging is a charging mode that has only become popular in recent years. The sweeping robot can return to a fixed charging base by itself. After the charging base detects the robot, it can charge it through induction. After the charging is completed, the robot leaves the charging base to continue working. . Compared with wired charging, wireless charging is more convenient and intelligent, but it also has the characteristics of low charging efficiency and fast battery life decay. In summary, in order to build a more intelligent and convenient sweeping robot system and fully realize its autonomous operation characteristics, the best choice is the wireless charging mode.
3. Drive motor
The reason why the sweeping robot can walk freely indoors is that the mechanical energy comes from the conversion of electric energy by the motor. The motor is the direct output device of the control system. The output shaft is directly connected to the robot's motion transmission device. The mechanical energy generated by the motor rotation drives the robot's actuator movement. By adjusting the speed, the robot can also complete a series of man-made movements. In terms of motor selection, the AC motor has a simple structure and low price, but its control accuracy is low. It is difficult to achieve the high-precision and low-speed working conditions of the sweeping robot, and it has the disadvantage of self-steering under certain circumstances; ordinary DC motors It can overcome the shortcomings of autobiography, and the stability is well guaranteed, but there is the problem of brush friction, which is not suitable for long-life sweeping robots; the stepper motor can complete precise movement, but its torque is small and the load is low, so it is large Most of them are used in instruments; brushless DC motors are small in size and mass, have good speed range, linearity, life and maintenance and replacement costs, and have low noise during operation, and there is no disadvantage of brushes. After adding permanent magnets, Its performance has been further improved. Combining the requirements of the sweeping robot for the size of the motor and the quiet environment in the home, the best choice for the motor is a brushless DC permanent magnet synchronous motor.
4. The actuator of the sweeping robot
As pointed out earlier, the output shaft of the motor directly drives the actuator to complete the action. The actuator is the device that the sweeping robot interacts with external forces and is a key part of the accuracy, flexibility and stability of the entire system. For sweeping robots, there are three types of actuators: leg-foot type, crawler type and wheel type. Leg-footed robots imitate the walking mode of spiders. They are still in the experimental stage, and their walking speed is very slow, which is not suitable for home use; crawler robots are more mature, but they are mostly used on uneven ground such as mud and sand. The driving speed is also slower. Considering the smooth road environment of indoor work, a simple wheel drive device is most suitable. This kind of actuator is composed of several wheel discs, with simple control mode, high energy utilization, small turning radius and fast response speed. The number and types of wheels will also affect the driving mode of the robot. Combined with the requirements of the range of motion and driving speed, the 4-wheel mode is most suitable for indoor cleaning work, and it is also conducive to the convenient realization of later trajectory planning.
5. Sensor
A sweeping robot cannot do without a variety of sensors when working indoors. The sensors are equivalent to the various sensory organs of the robot, similar to the human facial features. The robot sweeping needs to judge its own position, measure distance, speed, acceleration, pose, etc., detect obstacles around itself, and sometimes need to obtain information such as ambient temperature and humidity. The following sensors are required by the sweeping robot.
1) Accelerometer and gyroscope. Accelerometers and gyroscopes are devices for robots to measure displacement and angle. The accelerometer measures the acceleration of the robot, and the gyroscope measures the angular acceleration. The displacement and angular displacement of the robot are obtained through quadratic integration. The robot can be combined with the track estimation algorithm. Precise positioning.
2) Ultrasonic sensor. Ultrasonic sensors are a wide range of sensors, mainly used to detect obstacles and distance measurement. The ultrasonic transmitter head located at the front end can send and receive ultrasonic waves.
3) Infrared proximity sensor. Literally understood, this type of sensor generates a specific signal when it approaches an obstacle. After the infrared signal is bounced back when it encounters the obstacle, if the time and light intensity meet the requirements set in advance, it will judge the front To obstacles, this information is sent to the control mechanism so that the robot can avoid obstacles in time.
In addition to the above-mentioned sensors, there are also important sensors such as laser rangefinders, radar rangefinders, odometers, vision sensors, and temperature/humidity sensors.
In summary, with the continuous increase in the disposable income of residents, household sweeping robots have become an important smart home appliance that most households have purchased or are considering buying. Many home appliance companies are also focusing on developing autonomous sweeping robots, trying to share this. A huge market. The hardware selection and design of the sweeping robot are extremely critical, which directly affects the working mode and effect of the robot. A reasonable design of the hardware structure can improve the cleaning performance of the robot. It is the future to explore a more lightweight, efficient, energy-saving, and long-life hardware system. Direction of development.
Fourth, the problems that need to be solved in the sweeping robot solution
Although the application advantages of the intelligent sweeping robot are obvious, it effectively solves the user's cleaning burden. However, for now, there are also certain problems in the application of intelligent sweeping robots.
(1) The cleaning area of the intelligent sweeping robot is not comprehensive enough. The current intelligent sweeping robots have been set to have a cleaning function for a specific area. This is the infrared sensor technology mentioned above. The application cost of this technology is low, but the defects in the technology application process are obvious. When the robot is in use, its specific divergence port will emit rays. During the movement, the rays will be fed back to the microcomputer inside the system when they encounter some dark objects. After that, a certain memory will be formed on the memory panel of the robot, and it will choose to turn to clean other areas. However, as far as actual family life is concerned, the placement of many objects may appear messy, and the colors of furniture are also different in shades. In addition to the different shapes of indoor objects, infrared rays are difficult to reflect back scientifically and reasonably. As a result, the cleaning area of the robot may be divided, and some areas may be difficult to clean.
(2) Intelligent robots will have a certain destructive effect on irregular and cylindrical objects. In the actual cleaning process, the intelligent sweeping robot will automatically avoid obstacles when it encounters obstacles. Avoidance work can be divided into two parts: complete avoidance and buffer avoidance. If the intelligent sweeping robot uses ultrasonic bionic technology, it can effectively avoid various obstacles. However, as mentioned in the previous discussion, the application cost of ultrasonic bionic technology is not high, and the overall application range is not wide enough. Therefore, most of the sweeping robots currently used in households use infrared technology, which is limited to various solid and irregular obstacles; for those non-solid objects, such as various irregular objects, the system is relatively difficult to recognize. Therefore, it is easy for the sweeping robot to hit the corner of the table during the working process, causing certain damage.
(3) The intelligent sweeping robot is not strong enough to clean up various large particles. The intelligent sweeping robot has relatively strong adsorption capacity and can effectively clean all kinds of ordinary dust. However, the robot has certain restrictions, the suction caliber is relatively small, and the bristles of the roller brush of the sweeping robot are also spiral. In this way, some large particles are difficult to inhale, which will affect the cleanliness of cleaning.