During the production process in a certain automobile parts factory, materials are stored on the side of the line to supply the consumable materials used in the production line, which need to be supplemented in real-time. At present, it is carried by manual carts. When the carts reach the edge of the production line, the plastic boxes are manually lifted to the fluent strip shelf for storage, which is time-consuming and laborious. This plan plans to use AGV for this kind of handling process, thereby improving work efficiency, reducing labor intensity, and improving product safety.
The basic data is as follows: The size of the plastic box is 600×400×150 (mm), and the flat bottom can be stacked. Each box can load 16 pieces of materials on average. The size of the fluent strip rack is 1280×800×1500 (mm), which is divided into three layers: upper, middle, and lower. The upper and middle layers are used to store full bins, and the lower layer is used to store empty bins, as shown in Figure 1.
The automatic guided vehicle has a maximum load of 260kg and needs to complete three parts of the task: one is to transport the raw materials from the raw material area to the assembly line, and the bins are filled and exchanged; the second is to transport the semi-finished products to the painting area, and the bins are filled and exchanged, and the third is to move the line side. The finished products are transported to the finished product warehouse, and the bins are full for exchange.
1. automatic guided vehicle Solution planning
It can be seen in the planning diagram (Figure 2) that the upper left area is the raw material warehouse. There are 8 feeding points in the raw material warehouse. The red line in the figure indicates the walking route of the automatic guided vehicle. Task 1 is to perform task 1. The raw materials are transported to the assembly line. Because the workshop area is large and there are several unloading points, the task of transporting raw materials to the production line is relatively busy. The upper right area is the external spraying area. The black line in the figure indicates the walking route of the automatic guided vehicle. This is to perform task 2, transporting the semi-finished products to the spraying area (the workshop does not have a spray booth, and manual operation is required in this interface area. Others The transportation equipment transports the semi-finished products to the actual spray booth for the spraying process, then transports the parts back to the production line). The bottom area in the plan is the finished product warehouse area. Only some points in the production line produce finished products. The blue line indicates the walking route of the automatic guided vehicle. This is to perform task 3, which is to transport the finished products back to the finished product warehouse area. There are three unloading points in the finished product warehouse area. After finishing the unloading, the staff in the finished product warehouse area will arrange the goods and stack them for shipment. In each production line aisle, a double-row route is set to avoid blockage during the process of automatic guided vehicle staggering back and forth, which can improve the efficiency of operation.
2. Work flow
2.1 Bidding
The staff on the side of the production line will order materials through the button box according to the requirements of the production line, and then feedback to the system after wireless AP and other hardware communication.
2.2 Material preparation
The PC end of the loading point displays the required tasks of each station of the production line. After clicking to undertake the task, prepare the material. Carry out loading work on the standby automatic guided vehicle.
2.3 Shipment
The PC terminal of the loading point is given the carrying instruction, through the AP communication, the signal feedback system. The RCS robot scheduling system will automatically plan the route according to the task situation and give the automatic guided vehicle instructions, and the automatic guided vehicle will be shipped.
2.4 Cutting
After the automatic guided vehicle carries the designated goods and travels to a fixed location, the staff will transfer the bin to the storage shelf.
2.5 Stand by
The automatic guided vehicle without a scheduled task returns to the standby point to wait for instructions or replenish power.
2.6 Empty container return
Empty boxes are accumulated to a certain extent by the production line. It is loaded on the automatic guided vehicle by the staff and returned to the feeding point with the empty car for recycling.
3. The selection and parameters of automatic guided vehicle
- Basic size: 924×650×260(mm);
- Maximum lifting height: 60mm;
- Rated load capacity: 500kg;
- Maximum operating speed with full load: 1200mm/s;
- Navigation method: QR code navigation;
- Guiding positioning accuracy: ±10mm;
- Stop angle accuracy: ±1°;
- Working time: 24 hours continuous;
- Charging method: online automatic fast charging;
- AGV is equipped with multiple safety protection mechanisms (lidar detection, mechanical anti-collision module, material detection sensor, etc.), as well as intuitive signal lamp display and special situation alarm prompts. On the whole, this automatic guided vehicle can stably and effectively meet the needs of work.
4. automatic guided vehicle application technology
The latent lifting automatic guided vehicle is composed of the body, drive train unit, jacking mechanism, navigation system, power supply system, electrical control system, detection system, safety protection system, intelligent charger, and so on. The body is the installation base platform for the entire automatic guided vehicle, and all components are installed on the body. The driving wheel system unit is the actuator that keeps the automatic guided vehicle running and realizes the walking modes such as forward, backward, and turning through the differential control of the two wheels. The navigation system mainly judges its own position and angle through the visual recognition of the ground two-dimensional code and the angular positioning of the gyroscope. The power supply system uses a lithium iron phosphate battery as the power supply basic unit with additional power control to provide electrical energy for various functions of the automatic guided vehicle. The electrical control system includes the main controller, which is the brain of the automatic guided vehicle trolley, which is used to send walking control instructions to the driving wheel train unit of the trolley. The safety protection system is composed of lidar, safe collision edge, emergency stop button, etc. It is a guarantee for maintaining the safety of vehicles and related personnel. The smart charger is a device that charges the automatic guided vehicle. The automatic guided vehicle is set with a power threshold. When the power is lower than the set fixed power, the automatic guided vehicle can automatically return to the charging point and be automatically charged by the charger.
The overall hardware architecture of the automatic guided vehicle system mainly uses a local area network to realize the communication between the automatic guided vehicle, automatic guided vehicle management and monitoring computers, logistics management systems, production lines and databases. The overall hardware architecture design scheme is shown in Figure 4.
5. Matching calculation of production pace
Take the raw material warehouse to the No. 1 loading point as an example, the one-way distance L=42.7m, the proposed automatic guided vehicle to carry the materials at a stable speed V=0.5m/s, the total time for automatic guided vehicle rotation is t2=40s, and the time for personnel docking is t3= 50s. Then the automatic guided vehicle takes a total time to travel from the raw material warehouse to the No. 1 loading point.
According to this material point, the single product beat is Q=42s, and the automatic guided vehicle single-vehicle carries the material single product P=18 (box), then the automatic guided vehicle cycle times per hour (that is, 3600 seconds) is R=3600/(QP )=3600/(4218)=4.76 (times). Set the redundancy factor U=1.3, then the number of automatic guided vehicle units.
By analogy, there are 74 automatic guided vehicles that need to be transported in the overall layout, and the distances vary. According to statistical calculations, the automatic guided vehicle demand is 0.11, 0.19, 0.28, and so on. In the end, the cumulative sum and statistics show that the actual number of automatic guided vehicles, in this case, is 14.4 units, and rounded to the nearest 15 units can meet the demand of the production line.
6. Summary
This case solved the real-time feeding problem of the production line of an auto parts factory through the application of the latent lift automatic guided vehicle and became a successful application case in this industry. The planning of this application is based on the actual environment of the project site and adopts a reasonable route design, which effectively reduces the empty running time and waiting time of the automatic guided vehicle trolley and improves efficiency. The development of automated integrated manufacturing has brought the application and research of automatic guided vehicles into a new era. The biggest trend of modern logistics is networking and intelligence. In manufacturing enterprises, modern warehousing distribution centers are often integrated with enterprise production systems. As part of the production system, the warehousing system plays a very important role in enterprise product management.