Despite increasing automation, industrial trucks are still used in intralogistics in large quantities. In many areas, unit loads are stored on standardized loading aids as loading units in pallet racks. The storage and retrieval of goods in manually operated pallet racks is carried out with counterweight or reach trucks. The driver is responsible for the longitudinal and transverse guidance of the industrial truck as well as the control of the lifting device.
Inexperienced drivers of industrial trucks lack the necessary routine for positioning the forks in front of the most common loading aid: the Euro pallet. The limited space available in a warehouse working cycle and the rear wheel steering, which takes getting used to, lead to time-consuming corrections - the handling performance decreases.
In addition to the loss of time during pallet pickup, safety can also be endangered during this process: Too fast and careless manoeuvring leads to unwanted collisions between the industrial truck and its surroundings. The forks may damage the Euro pallet, the goods or the pallet rack. The latter can considerably reduce the load-bearing capacity of the rack elements and lead to instability.
For the described initial situation a system is to be developed, which supports the driver of industrial trucks with the admission of a euro pallet, as m spread LHM. The desired research result comprises a demonstrator which shows the technical feasibility and at the same time serves as a basis for an evaluation. The evaluation should show that a driver assistance system makes the operation of industrial trucks more efficient and safer. An assistance system with the required functionality is divided into the following subsystems: object recognition, localisation, path planning, man-machine interface and vehicle control.
Based on object recognition, the driver should be able to select the desired target pallet via a user interface. The object recognition, consisting of sensor technology and image processing, must recognize and localize the pallet in front of the vehicle. Taking into account the relative position and the vehicle geometry, the optimal trajectory for the entry of the forks in the pallet entry openings is calculated. The driver then simply presses the accelerator pedal. The driver assistance system adjusts the steering angle as a function of the vehicle speed so that the calculated trajectory is run.
On the basis of a market analysis and the functions of the subsystems of the new driver assistance system, a list of requirements and a concept are drawn up. A 3D time-of-flight camera is used to recognize and localize the pallet. The recognition of the pallet takes place in the 3D point cloud, which is supplied by the camera as a measured value. After the recognition of one or more pallets in the visible area of the camera, the relative pose between camera and pallet is calculated based on the depth information. From the pose and the vehicle geometry, an optimal trajectory for the entry of the forks into the entry openings is calculated. The driver must interact with the assistance system to select the pallet to be recorded. The focus here is on the human-machine interface, which comprises the hardware for the visualization and the input options.
For the construction of a demonstrator for the partial automation of vehicle functions, the technical implementation possibilities on the test vehicle are investigated. Finally, objective and subjective criteria are recorded and evaluated in an evaluation with test persons.
The research project "Advanced driver assistance systems for industrial trucks" is funded by the Dr. Friedrich Jungheinrich Foundation.