How to choose a suitable LiDAR solution for unmanned forklift in complex application scenarios?

Since 2023, unmanned forklifts have become the most popular product in the field of mobile robots.

According to the latest report by the QYResearch team, titled "Global Unmanned Forklift Market Report 2023-2029," it is expected that the global unmanned forklift market size will reach 1.69 billion US dollars by 2029, with a compound annual growth rate (CAGR) of 11.5% in the coming years.

As the core sensing component, LiDAR determines the upper limit of positioning, navigation, sorting, and path planning capabilities, it can affect the unmanned forklifts performance on customer field sites directly.

At present, the application scenarios of LiDAR in the field of unmanned forklifts mainly include navigation, obstacle avoidance, and recognition. With the intensification of competition among unmanned forklifts, the LiDAR also face a more complex and diverse environment, which raised a higher requirement for different types of LiDAR. 

From 2D to 3D, navigation LiDAR has made new breakthroughs while also maintaining stability

The navigation LiDAR of forklifts mainly uses 2D or 3D LiDAR. 2D LiDAR, also known as single-line LiDAR, has fast scanning speed and high horizontal resolution, but its planar scanning method limits the detection information and mainly suitable for indoor scenes. 3D LiDAR, also known as multi-line LiDAR, can identify the three-dimensional information of objects and suitable for indoor and outdoor shuttle scene applications.

(1) 2D navigation LiDAR need to consider both performance and stability.

Due to high production costs and complex application environments, unmanned forklifts have not been widely adopted on a large scale.

Narrow passageway and high loads are high-frequency words in the introduction of unmanned forklift products. When using a heavy-duty unmanned forklift in a narrow passage scenario, and meanwhile limit the driving and turning radius, this places extremely high demands on the sensing positioning accuracy of LiDAR which installed into the forklift.

In addition, factories operated by unmanned forklifts often have large areas and long transportation distances between different production lines, so forklifts need to operate at a high speeds. To meet the high-speed scenarios requirement, LiDAR need to have far detection distance, high scanning frequencies and fast response speed.

Stability is also an important consideration criterion for LiDAR, including consistency in LiDAR performance, stability during on-site operation, etc., to ensure the smooth operation of unmanned forklifts and reduce maintenance costs.

Take the VanJee WLR-719 LiDAR as an example, this is a high-performance LiDAR applied to unmanned forklifts. The measure distance can reach 50m and can identify reference objects at a far distance in factory. It’s highest resolution can reach 0.033 °, and with a maximum frequency of 30Hz. It not only can capture environmental information around high-speed operation forklifts, but also can meet the accuracy requirements for inserting and moving goods.

(2)3D LiDAR, meet the requirements of navigation both in indoor and outdoor

With the promotion of unmanned forklift, it is an inevitable trend for forklifts to go out of warehouses and interact with outdoors container trucks and flatbed trucks. By installing 3D LiDAR, the forklift's sensing ability can be greatly improved, and complete the transportation of complex scenes in indoor and outdoor.

At present, the 16 line/32 line mechanical 3D LiDAR were used in most indoor and outdoor shuttle unmanned forklift.

As shown in the below figure, 3D LiDAR can clearly sense the three-dimensional contour information of the environment and obtain accurate resolution information by scanning the solid space. Not only does it make navigation more accurate, but also provides precise and reliable information support for obstacle avoidance. VanJee SLAM mapping effect based on 720 LiDAR

The main challenges to 3D LiDAR outdoor application include environmental interference, compatibility with indoor scenes, and recognition of reference objects such as trees and road surfaces based on outdoor scenes.

For example, the VanJee 16 line LiDAR WLR-720, which is applied on indoor-outdoor shuttling unmanned forklifts at photovoltaic factories, not only provides a horizontal zero degree line for easy integration with existing indoor and outdoor reflector features, but also forms a 360 °x 31 ° field of view around the forklift, which can accurately detect environmental obstacles such as road surfaces and low objects, achieve both navigation and obstacle avoidance function, and great support for outdoor scene operations.  

Obstacle Avoidance LiDAR, prioritize quality beyond price

In the warehouse workshop, there are numerous shelves and narrow passageways. To avoid collisions with unmanned forklifts, safety protection need to be considered in priority. The main function of obstacle avoidance LiDAR is to ensure the safety of forklift operation. Currently, there are three main trends in the development of obstacle avoidance LiDAR:

(1) Higher requirement for cost-effectiveness. Three or more obstacle avoidance LiDAR need to be installed into a high-performance unmanned forklift, it is important to control the general manufacturing cost.

(2)The LiDAR needs to be designed lighter weight, to reduce the volume of the unmanned fork body to operate in narrower tunnels, also to meet safety protection requirement in reverse parking scenarios, generally need to embed protective LiDAR at the fork tip of forklift.  

(3)The LiDAR requires a higher environmental adaptability. As the application of unmanned forklifts becomes more and more widespread, it not only be used in clean and dust-free workshops, but also facing some new manufacturing fields, such as chemical plants, steel mills, and furniture manufacturing. In these scenarios, it is normal have an interference to LiDAR from dust, rain, fog and strong light.

For example, the VanJee obstacle avoidance 718H LiDAR, which applied on below robotic forklift, follow the strict quality standard of VanJee LiDAR, can achieve ±30mm accuracy within whole measurement range, the farthest measurement distance can reach 25m. The 718H LiDAR has a height of only 42.9mm and can be easily embedded into the fork tips of unmanned forklifts. The normal working temperature range of LiDAR is from -20℃ to 60℃, and not affected by the interference from dust, rain, sunlight. With its super strength, can provide a perfectly protection for industrial robots.

From vision to laser, breaking through the difficult points in cargo recognition scenarios

To achieve the operation of inserting and placing goods, unmanned forklifts must accurately identify the position of the pallet and the surrounding environment. Previously, most unmanned forklifts used industrial TOF cameras or depth cameras for perception. However, the camera's perception accuracy is limited, and it is easy to produce noise in ambient light interference. In this case, the unmanned forklifts limited to indoor application as well as the standard pallet which have stable feature points, it can not be used in non standardized pallet warehouses. Compared to cameras, solid-state LiDAR has higher accuracy, and it also comes with position information, not affected by environmental interference, can better identify complex positions such as pallets, cages, etc.

For example, the outdoor unmanned forklift was integrated with VanJee 750 LiDAR, which has a maximum angular resolution of 0.33°* 0.33°, can help the forklift clearly identify the structure of various materials. If also combined with environmental mapping of 3D SLAM navigation algorithm, the forklift can achieve difficult stacking of irregular objects in outdoors.

From the general situation of forklift market, the penetration rate of unmanned forklifts is still relatively low. Only through collaborative cooperation and common development between unmanned forklift enterprises and LiDAR enterprises can we break through the barriers of further market, help manufacturing enterprises to achieve cost reduction and efficiency improvement, and seize the opportunity of large-scale intelligent upgrading of equipment.