AMR autonomous mobile robot solution using sensors

1. Application Challenges

As an important part of modern warehousing and logistics applications, more and more autonomous mobile AMRs are put into use in cargo transportation. AMRs can automatically realize the transportation of goods between workstations. In the transfer station, after the goods are automatically loaded and unloaded, the AMR shuttles back and forth between several workstations. In order to smoothly and safely transfer goods, we need to ensure that the AMR is safely parked at the required workstation , and during the transportation process, the transmission between the AMR and the transfer station is as simple and reliable as possible to control the AMR to park the goods in the correct direction at the required loading and unloading position.

2. Goals

The key point of this application is the need to create a stable and reliable signal transmission method for controlling the loading and unloading process . The information transmission must be reliable and stable even if there are metal structures in the surrounding area that may interfere with the connection between the AMR and the station. In some cases, it may also be necessary to confirm that the AMR is parked at the correct station to transmit the signal, which also requires the AMR to be able to easily and quickly identify its target position . Regardless of the AMR path, even if the vehicle is not accurately aligned or there are slight bumps or vibrations on the route, the component needs to receive the light signal from the transmitter in advance. The standard through-beam type is not suitable because the light spot is too small, and the AMR cannot find its position quickly and correctly. Standard through-beam sensor systems also cannot compensate for displacement deviations when the vehicle is parked or position changes caused by uneven ground.

3. Solution

The BB10-P-F1/BB10-P-F2 series Through-beam sensors offer the ideal complete solution. By using two through-beam sensors , a simple two-bit communication is established to trigger loading and unloading at the transfer station. The signal from the first sensor is used to position the trolley , the second sensor triggers the loading or unloading process . By using two through-beam sensors with different transmission frequencies, process safety of the signal transmission can be achieved . Crosstalk caused by reflections from metal parts is prevented even when the sensors are placed very close together.

This signal transmission method can also be used to confirm that the correct transfer station is being reached before accurately positioning the AMR . This function is based on the use of a through-beam with an optical pulse frequency of F1 on the AMR. The transmitter is paired only with the receiver installed at the station. By simply activating the receiver of the transfer station, the corresponding station can be easily confirmed over a long distance using the BB10 through-beam sensor, while the receivers of the unactivated workstations are inactive. Even if the vehicle is not perfectly aligned or there is vibration from the trolley, the appropriate spot size and receiver beam divergence angle can ensure reliability.

BB10-P-F1/BB10-P-F2 Series

Technical characteristics

■ Through-beam sensor with no blind spot, sensing range is 0m to 3m

■ Large spot (350mm diameter, 3m distance) and large divergence angle

■ Two optical pulse frequencies

■ Anti-interference light

■ Plug-in housing for easy front-mounting

■ Up to IP67 protection level

4. Advantages

The use of two sets of counter-beam sensors ensures a simple, reliable, economical and efficient two-way communication . This method, similar to the data coupler, can use two different transmission frequencies for communication between the vehicle and the target workstation: first, the sensor group with light pulse F1 detects whether the workstation is correct, and the second set of sensors with light pulse frequency F2 is used to trigger the loading or unloading process. Unlike the AMR, in certain areas of the environment with many metal components, wireless communication may suffer from signal energy loss. The signal of this type of two-way communication is stable and not easily disturbed . The sensor is not affected by wireless communication or bandwidth compliance rules, and the use of two sets of photoelectric with different light source frequencies can prevent crosstalk caused by beam reflection . In addition, the sensor device emits infrared light that is invisible to the human eye, so it is friendly to human vision and does not dazzle.

5. Product Features Highlights

■ Large light spot and large divergence angle ensure reliable detection at the transfer station

■ Strong optical signal connection, no metal component interference

■ Two transmitter frequencies, can be installed in parallel to achieve more functions

■ Infrared light signal invisible to human eyes, safe for human eyes

■ Direct plug-in installation, no bracket required

Editor: Huang Fei