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Sweeping robot hardware structure

Update:17-05-2019
Summary:

The power supply of the sweeping robot with multiple de […]

The power supply of the sweeping robot with multiple devices operating at the same time.
The third is that the temperature adaptability is very strong, and it can work normally between -20 ° C and 60 ° C, while the ordinary household indoor temperature is between 0 ° C and 40 ° C, which fully meets the requirements;
The fourth is that lithium-ion batteries do not contain heavy metals and harmful substances, and do not cause excessive damage during use, scrapping and recycling.
However, lithium-ion batteries have their own problems, such as chemically active, explosive, etc., which requires special attention when used.Household Vacuum Cleaners Manufacturers
Lithium-ion batteries are widely used in mobile electronic devices, such as mobile phones, notebook computers, and tablets. Therefore, in line with the advantages of lithium-ion batteries, sweeping robots should choose such batteries as the power source. Taking into account the actual work content and duration of the sweeping robot, use 6 1.2V
3 000 mAh lithium ion battery.
1.2 Charging equipment
The charging device is also called a charging base in the system of the sweeping robot, similar to the electric vehicle charging pile. Because the charging device is fixed in position, the cleaning robot needs to be reciprocated to charge back and forth.
Similar to most household appliances in the home, the cleaning base of the sweeping robot also uses the voltage and current standard of 220V AC. The charging device can obtain power 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 be stepped down, rectified, filtered, etc. 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 burning and explosion.
This process can also be replaced by a power adapter that conforms to the specifications. In terms of charging form, it is currently divided into two main forms of wired charging and wireless charging. Wired charging is similar to charging of ordinary electronic devices. When the cleaning robot reaches the charging warning line, it will automatically issue an alarm. After the user finds it, it can be connected to the charging device through the cable in time.
The advantage of wired charging is that the device is relatively simple, low in cost, and has little impact on the life of the battery. 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 the fixed charging base by itself. After the charging base detects the robot, it can charge it by induction. After the charging is completed, the robot will leave the charging base and continue to work. .
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 smarter and more convenient sweeping robot system and fully realize the characteristics of its own operation, the best choice is the wireless charging mode.
1.3 drive motor
The reason why the sweeping robot can walk freely indoors, the mechanical energy is from the motor to the conversion of electric energy, the motor is the direct output device of the control system, the output shaft is directly connected with the motion transmission device of the robot, and the mechanical energy generated by the rotation of the motor drives the robot actuator to move. By adjusting the speed, the robot can also perform a series of human-operated motions.
In terms of motor selection, AC motor has a simple structure and low price, but its control precision is low, it is difficult to achieve high-precision and low-speed working conditions of the sweeping robot, and there are disadvantages of self-steering under certain circumstances;
Ordinary DC motors can overcome the shortcomings of autobiography, and the stability is well guaranteed, but there is a problem of brush friction, which is not suitable for long-life sweeping robots;
The stepper motor can perform precise movement, but its torque is small and the load is low, so most of it is used on the meter;
The brushless DC motor has small volume and quality, has good speed regulation range, linearity, life and maintenance replacement cost, and has low noise during operation. There is no drawback of the brush. After adding permanent magnets, its performance is further improved. Combined with 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 the brushless DC permanent magnet synchronous motor.
1.4 Executive agency
As pointed out above, the output shaft of the motor directly drives the actuator to complete the action. The actuator is the device that acts as the sweeping robot and the external force. It is a key part that determines the accuracy, flexibility and stability of the whole system.
For sweeping robots, the actuators that can be selected are leg-foot, crawler and wheel.
The leg-foot robot mimics the way the spider walks, and is still in the experimental stage, and the walking speed is very slow, which is not suitable for home use;
Tracked robots are relatively mature, but they are mostly used on uneven ground such as mud and sand, and the speed is slow.
Considering the smooth road environment for indoor work, simple wheeled
The driving device is most suitable. The actuator is composed of a plurality of discs, the control method is simple, the energy utilization rate is high, the turning radius is small, and the reaction speed is fast.
The number and type of wheels also affect the driving mode of the robot. Combined with 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 implementation of the later trajectory planning.
1.5 sensor
The sweeping robot is inseparable from a variety of sensors when working indoors. The sensor is equivalent to the various sensing organs of the robot, similar to the human facial features. The sweeping robot needs to judge its position during work, 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 necessary for the sweeping robot.
1) Accelerometers and gyroscopes. Accelerometers and gyroscopes are devices for measuring displacement and angle. The accelerometer measures the acceleration of the robot. The gyroscope measures the angular acceleration. The displacement and angular displacement of the robot are obtained by quadratic integration. Precise positioning.
2) Ultrasonic sensor. Ultrasonic sensors are a wide range of sensors used to detect obstacles and ranging. The ultrasonic transmitter at the front end can transmit and receive ultrasonic waves. The principle of ranging is very simple, using the formula:
3) Infrared proximity sensor. It is literally understood that when such a sensor approaches a obstacle, it generates a specific signal. When the transmitted infrared signal is bounced back after the obstacle is reached, if the time and light intensity reach the set requirement in advance, then the front is met. To the obstacle, this information is sent to the control mechanism so that the robot can avoid obstacles in time.
In addition to the above sensors, there are important sensors such as laser range finder, radar range finder, odometer, vision sensor, and temperature/humidity sensor.

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