With the development of industrial automation and intelligence, mobile robots have been widely used in the field of manufacturing, and gradually extended to other industries. In recent years, with the increasing demand for intelligent manufacturing, lean production and flexible production, the requirements for mobile robot technology are also rising. At present, the common mobile robot navigation methods in the market include magnetic stripe navigation, two-dimensional code navigation, laser reflector navigation and laser natural contour navigation. However, it is always difficult to meet the needs of complex use scenarios by relying on one or two sensors for positioning and navigation.

The working principle of the traditional magnetic stripe navigation mobile robot is to lay the magnetic stripe on the ground, make the direction of the magnetic stripe magnetic field consistent, and realize the guidance of the mobile robot through the magnetic signal induced by the magnetic sensor. When starting the magnetic guide mobile robot, pay attention to whether the robot is in the middle of the guide magnetic strip, and the left-right deviation shall not be greater than 10cm; Moreover, the mobile robot must travel according to the laid magnetic stripe track, which has poor flexibility and is difficult to meet the current flexible production requirements.

QR code navigation belongs to visual recognition, which recognizes the QR code laid on the ground through the camera (QR code collector), senses the position and attitude of the mobile robot through the inertial navigation module (gyroscope), and feeds back the collected information to the controller. The advantage of two-dimensional code navigation is that compared with magnetic conductivity, it is relatively easy to lay and change the path, and has strong anti-acoustooptic interference; Its disadvantage is that the two-dimensional code on the ground is easy to wear and needs regular maintenance. It has high requirements for the accuracy and service life of the gyroscope, as well as high requirements for field leveling.

The working principle of laser reflector navigation is to install a laser reflector with accurate position around the driving path of the mobile robot, emit the laser beam through the lidar, collect the laser beam reflected by the reflector to determine its current position and direction, and realize the robot navigation through continuous triangular geometry operation. Its advantage lies in accurate positioning and relatively flexible installation of reflector; Its disadvantage is that it still does not get rid of the dependence on the auxiliary positioning facilities of the reflector, has high requirements for the installation accuracy of the reflector, and has certain requirements for the ground environment and light environment.

Xianzhi laser slam navigation integrates multi-sensor algorithm to make the mobile robot more intelligent

Laser natural contour navigation does not need auxiliary positioning facilities such as magnetic stripe, two-dimensional code and reflective column. It adopts slam technology and uses lidar to continuously transmit pulses to the surrounding environment to obtain point cloud information, which is matched with the map scanned, stored and uploaded in advance, so as to realize positioning navigation. Its advantage is that it does not need any transformation of the use environment, has strong autonomy, flexibility and accurate positioning, and can meet the flexible production and handling needs of flexibility; However, there are some problems. It is easy to lose location in complex environments with few references such as corridors and high dynamic.

Comparing the above four navigation modes, it will be found that laser natural contour navigation is the most flexible and convenient navigation mode, but there is still room for improvement. As a high-tech enterprise with control and scheduling as the core, Xianzhi robot creatively solves this problem. On the basis of laser natural contour navigation, it integrates laser reflector navigation, two-dimensional code navigation, inertial navigation, camera, etc., and adopts multi-sensor fusion algorithm to make the positioning of mobile robot more accurate, more powerful and universal, It can cope with corridors, high dynamic complex environment and ground pits.

In the corridor and high dynamic environment, you can freely switch to laser reflector navigation and QR code navigation to ensure that the positioning will not be lost; When the ground environment is relatively poor, a 3D camera can be selected to identify and detect ground pits and three-dimensional obstacles, and let the mobile robot choose to stop or bypass according to the parameter configuration.

In addition, in order to ensure the safety of mobile robots, Xianzhi robot also has a series of methods to ensure the safety of robots, personnel and goods during the use of mobile robots. Such as dual laser solution, complete 360 ° all-round safety detection around the mobile robot through dual laser; In the SRC based laser slam automatic forklift solution, safety protection is carried out through 3D camera, infrared sensor, ultrasound, safety touch edge, etc., so as to ensure the safety of personnel and goods during the operation of automatic forklift.

At the same time, with the unified resource scheduling system SRD independently developed by Xianzhi and the one-stop implementation tool roboshop pro, all kinds of mobile robots can give full play to their best performance. Through SRD, it can seamlessly connect with the ERP, MES, WMS, WCS and other systems of the factory, and connect the mobile robot with the elevator, electric door and production equipment of the factory, so that the mobile robot can operate flexibly in the factory workshop and warehouse, complete the operation tasks efficiently, and help the factory build a real digital and intelligent chemical plant.

     

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