An electrical control system and method for an omnidirectional unmanned counterbalance forklift

Abstract

This invention belongs to the field of unmanned vehicle control technology, specifically disclosing an electrical control system and method for an omnidirectional unmanned counterbalance forklift. The system includes a main control module, a mast control module, a chassis control module, a sensor module, a communication module, a battery module, and a human-machine interaction module. The main control module runs a robot operating system and is responsible for task scheduling, path planning, and decision control. The mast control module communicates with the main control module via Ethernet TCP / IP protocol to control the mast's lifting, tilting, and lateral movement. The chassis control module controls the omnidirectional moving chassis via a CAN bus. The sensor module includes a lidar, a recognition camera, photoelectric switches, and a pull-wire encoder to achieve environmental perception and status detection. This invention adopts a distributed control architecture and solves the problems of low control accuracy, slow response, and poor stability of existing unmanned forklifts through multi-sensor fusion and real-time communication, achieving high-precision positioning, autonomous navigation, and stable operation.

Description

Technical Field

[0001] This invention relates to the field of unmanned vehicle control technology, and in particular to an electrical control system and method for an omnidirectional unmanned counterbalance forklift. Background Technology

[0002] With the rapid development of industrial automation and intelligent logistics, unmanned forklifts, as core equipment for automated material handling, are increasingly being used in warehousing, manufacturing, and other scenarios. Traditional unmanned forklifts mostly adopt one-way or two-way travel modes. When operating in narrow aisles or between dense racks, they suffer from low space utilization, poor operational flexibility, and low efficiency due to their large turning radius and the need for multiple adjustments to their position. To improve forklift flexibility, new types of unmanned forklifts with omnidirectional mobility have emerged. These forklifts, by adopting omnidirectional chassis such as Mecanum wheels and steering wheels, can achieve translation and rotation in any direction within a plane, greatly improving the forklift's maneuverability in extreme spaces.

[0003] The ability of omnidirectional forklifts to achieve complex movements and precise operations relies heavily on their electrical control systems. In other words, the electrical control system is a key factor limiting the performance and reliability of omnidirectional forklifts. Traditional forklift control systems have the following shortcomings: 1. Insufficient system real-time performance and reliability: Most existing mainstream solutions adopt a centralized control architecture, that is, a single central processor manages all tasks of perception, decision-making and execution. This centralized architecture is prone to processor overload, resulting in response delays when multiple tasks are processed concurrently (such as real-time navigation, dynamic obstacle avoidance, and gantry precision control), making it difficult to guarantee real-time performance. More importantly, this architecture has the risk of single point of failure. Once the main controller fails, the entire system will be paralyzed, resulting in low reliability. 2. Poor coordination of the sensing system and limited control accuracy: To achieve omnidirectional movement and precise forklift picking, the system needs to integrate multiple sensors such as LiDAR, vision cameras, and encoders. However, existing control systems often process the data collected by each sensor separately or simply fuse them, resulting in poor data fusion effects. This fails to fully leverage the advantages of complementary multi-source information, leading to significant room for improvement in positioning accuracy, cargo recognition success rate, and gantry pose control accuracy in dynamic environments. 3. Significant communication response delay: The communication protocols or inefficient bus networks used between various functional modules (such as main control, chassis drive, and gantry actuator) introduce significant delays in command transmission and status feedback, which directly affect the control accuracy and dynamic response performance of the whole vehicle.

[0004] Therefore, there is an urgent need to develop a modular, highly flexible, highly real-time, and highly reliable omnidirectional unmanned counterbalance forklift electrical control system to solve the above-mentioned technical bottlenecks and meet the high-requirement operation in complex industrial scenarios. Summary of the Invention

[0005] The purpose of this invention is to overcome at least one of the shortcomings of the prior art and provide an electrical control system and method for an omnidirectional unmanned counterbalance forklift, so as to improve control accuracy, real-time performance and reliability.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an electrical control system for an omnidirectional unmanned counterbalance forklift, including a main control module, a mast control module, a chassis control module, a sensor module, a communication module and a power supply module; The main control module uses the LPB3588 controller, which is based on the ARM architecture and has an 8-core CPU and an NPU with 6 TOPS computing power. It runs the robot operating system and is responsible for global path planning, task scheduling and decision control. The gantry control module uses a Siemens S7 1200 series CPU1214 PLC, which communicates with the main control module via TCP / IP industrial Ethernet, receives instructions from the main control module, and controls the oil pump motor and lifting, side-moving, and tilting valves to realize the lifting and side-moving of the forks and the forward and backward tilting of the gantry. The chassis control module uses the SRC 2000 motion controller, which communicates with the main control module via TCP / IP industrial Ethernet and controls the drive motors and steering motors of the four steps via CAN bus to realize the forklift's forward, backward, left, right, rotation and omnidirectional movement in any direction. Sensor modules are used for environmental perception and forklift status detection; The communication module is used for data communication between modules and wireless communication with external systems. It includes internal communication and external communication. Internal communication uses a gigabit industrial Ethernet switch to connect each control module. External communication uses a WIFI / 5G communication module to communicate with the remote monitoring center and dispatch system. The power module can convert the forklift's 48V battery voltage to the voltage required by each module (24V, 12V) and provide overcurrent, overvoltage, and short-circuit protection.

[0007] Furthermore, the sensor module includes a LiDAR, a recognition camera, photoelectric switches, and a pull-wire encoder. The LiDAR is a 360-degree rotating scanning LiDAR, installed on the top and sides of the forklift, with a scanning radius of 30 meters, used for mapping, positioning, and obstacle avoidance. The recognition camera is a binocular vision camera with a resolution of 1920×1080, installed in the middle of the mast, used for fork recognition, pallet recognition, and obstacle recognition. The photoelectric switches are installed on both sides of the mast and at the fork tips, used to detect the extreme positions of the fork height and the fork's position. The pull-wire encoder is installed at the mast's lifting, lateral movement, and tilting points, with a measurement range of 0.3 meters and an accuracy of ±1 mm, used to accurately measure the real-time position of the mast.

[0008] Furthermore, it includes a safety protection module, which is connected to the sensor module and the main control module for emergency braking, obstacle warning, and system fault diagnosis.

[0009] Furthermore, the safety protection module includes: an emergency stop button connected to the main control module; an audible and visual alarm for alarming abnormal conditions; and anti-collision contact edges for safety detection and emergency stopping.

[0010] Furthermore, the robot operating system deployed in the main control module includes: a navigation function package for SLAM mapping and path planning; a control function package for motion control and gantry control; a perception function package for processing sensor data; and a communication function package for communication between modules.

[0011] Furthermore, it includes a human-machine interaction module, which includes a 10.1-inch industrial touchscreen and status indicator lights for parameter setting, status display, and fault alarm.

[0012] The beneficial effects of this invention are: 1. This invention abandons the traditional single centralized controller scheme and adopts a distributed control architecture in which the main control module, gantry control module, and chassis control module are independent of each other. This design can distribute the computing load to each dedicated controller, effectively reducing the burden on the main processor and greatly improving the real-time performance and response speed of the system in handling multiple tasks. At the same time, each module is relatively independent in function, and the failure of a single module will not cause the entire system to fail, thereby significantly improving the overall reliability and fault tolerance of the system. 2. This invention integrates LiDAR, recognition camera, photoelectric switch, and pull-wire encoder into a sensor module, which works in conjunction with the sensing function package of the main control module to achieve multi-dimensional, high-frequency perception of the environment and the forklift's own state. The main control module performs deep fusion processing on multi-source heterogeneous sensor data, giving full play to the complementary advantages of different sensors, thereby significantly improving the accuracy of simultaneous localization and mapping (SLAM) of forklifts in dynamic and complex environments, the success rate of cargo and pallet recognition, and the millimeter-level closed-loop control accuracy of mast lifting, lateral movement, and tilting posture. 3. Based on the characteristics of each control subsystem, this invention employs differentiated industrial-grade communication protocols. For example, the main control module and the gantry control module use the Ethernet TCP / IP protocol, suitable for transmitting complex control parameters and status information; while the chassis control module, which has extremely high real-time requirements, uses the CAN bus protocol for command and feedback transmission. This hierarchical and dedicated communication design greatly reduces communication latency between modules, ensuring the immediate issuance of motion control commands and the real-time transmission of status feedback, providing a solid foundation for the high dynamic and high-precision omnidirectional movement of the forklift.

[0013] 4. The electrical control system in this invention adopts a clear modular design, with well-defined boundaries and standardized interfaces for each functional module (main control, sensing, execution, communication, human-machine interaction, power supply, and safety). This design makes the system easy to expand, upgrade, and maintain. When it is necessary to update a function (such as replacing it with a higher-performance sensor) or to perform fault diagnosis, specific modules can be operated, significantly reducing the cost of system upgrades and the difficulty of later maintenance. Attached Figure Description

[0014] Figure 1 This is a block diagram of the overall architecture of the electrical control system of the present invention; Figure 2 This is a schematic diagram of the drive control principle of the chassis control module of the present invention; Figure 3 This is a control principle diagram of the gantry control module of the present invention; Figure 4 This is a schematic diagram showing the installation positions of the electronic control system and sensor module of the present invention. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings. Example

[0016] like Figure 1-3 As shown, this embodiment provides an electrical control system for an omnidirectional unmanned counterbalance forklift. The system adopts a modular, distributed architecture and mainly includes a main control module, a mast control module, a chassis control module, a sensor module, a communication module, a power supply module, a human-machine interface module, and a safety protection module. The following is a detailed description of each module: 1. Main control module The main control module, serving as the system's decision-making and control core, employs an LPB3588 controller, equipped with 16GB of RAM and 128GB of storage. It supports multiple operating systems, including Android, Buildroot, Debian, and Ubuntu. In this embodiment, its robot operating system integrates and deploys the following software packages: Navigation function package, enabling SLAM mapping and path planning; The control function package generates control commands to achieve motion control and gantry control; The perception function package processes data from sensors such as LiDAR and cameras; The communication function package manages communication between modules.

[0017] 2. Gantry control module The gantry control module uses a Siemens CPU1214 PLC, configured with 14 digital inputs, 10 digital outputs, and 4 analog inputs. It communicates with the main control module via TCP / IP, with a communication cycle of 1ms. Photoelectric limit switch signals are connected to the PLC's digital inputs, and wire encoder signals are connected to the analog inputs. The PLC controls the gantry oil pump motor drive and the lifting, lateral movement, and tilting proportional valves according to the main control instructions, achieving closed-loop control based on feedback values ​​from the wire encoders. 3. Chassis control module The chassis control module uses the SRC-2000 motion controller, which communicates with the main control module at high speed via Ethernet TCP / IP protocol with a communication cycle of 250μs to ensure real-time motion commands. It connects to the motor drivers that drive the four omnidirectional steering wheels via a CAN bus. Each drive motor is equipped with an absolute encoder to provide precise position and speed feedback. The SRC-2000 motion controller internally performs kinematic calculations for omnidirectional movement and implements closed-loop control of the speed and position of each steering wheel based on encoder feedback, ultimately driving the forklift to achieve smooth forward, backward, lateral, rotational, and combined movements in any direction.

[0018] 4. Sensor Module The sensor module provides the system with environmental perception and its own state detection information. For example... Figure 4 As shown, the specific installation locations and functions of each sensor are as follows: LiDAR: Installed at the center of the top of the forklift (about 2.5 meters above the ground), it adopts a 360° rotating scanning method and is mainly used for environmental modeling, real-time positioning and dynamic obstacle avoidance.

[0019] Recognition Camera: A binocular vision camera is installed in the middle of the mast beam and facing the forks for pallet recognition, rack recognition, and short-range obstacle recognition.

[0020] Photoelectric switches: installed at specific heights on the uprights on both sides of the mast (such as 0.1 meters and 2.3 meters from the ground) and at the fork tips, used for limit position protection and position detection of fork lifting.

[0021] Pull-wire encoder: Installed on the lifting, lateral movement and tilting mechanism of the mast, it is used to measure the absolute position of the mast and forks in real time and with high accuracy.

[0022] 5. Power Module The power module uses a DC-DC converter to convert 48V battery voltage to 24V and 12V. The 24V voltage is used by PLC, motion controller, lidar and other equipment; the 12V voltage is used by camera, photoelectric switch and other sensors and some control circuits. The power module also has overcurrent, overvoltage and short circuit protection functions.

[0023] 6. Human-computer interaction module In this embodiment, the human-machine interface module uses a 10.1-inch industrial touchscreen with a resolution of 1920×1080, which is installed at the rear of the forklift. The touchscreen can display the forklift's operating status (such as position, speed, and battery level), task information, and environmental map in real time, and provides an interface for system parameter settings, task assignment, and fault alarm information query.

[0024] 7. Safety Protection Module The security protection module includes: Emergency stop buttons: Hardware emergency stop buttons are provided in the front, rear, left and right directions of the forklift body. Pressing them can directly cut off the power or trigger the highest level of stop command. Audible and visual alarm: Installed on the roof of the vehicle, it can emit audible and visual warnings when the system starts up, turns, malfunctions, or in an emergency; Anti-collision contact edge: This is a physical safety sensor installed on the outer perimeter of the front, rear, and sides of the vehicle body. When it comes into physical contact with an obstacle, it immediately triggers an emergency stop. LiDAR: Installed on the top and sides for navigation and obstacle avoidance parking; The control method based on the above electrical control system mainly includes the following steps: S1. Environmental and State Perception: The sensor module acquires real-time information about the surrounding environment (such as maps and obstacles) and the forklift's own status (such as mast position and speed). S2, Task Planning and Decision-Making: Based on the tasks issued by the upper-level scheduling system and combined with the information from S1, the main control module performs global path planning and real-time decision-making, generating the chassis motion path and gantry action sequence. S3, Chassis Omnidirectional Movement Control: The chassis control module receives path instructions from the main control module and drives four omnidirectional steering wheels through a closed-loop control algorithm, enabling the forklift to move precisely along the planned path. S4. Precision motion control of the gantry: The gantry control module receives the work instructions issued by the main control module, controls the hydraulic system to drive the gantry to complete the specified lifting, lateral movement or tilting actions, and realizes closed-loop position control through encoder feedback; S5. Security Monitoring and Protection: Throughout the operation, the safety protection module continuously monitors the system status. Once an abnormal situation is detected, such as emergency stop triggering, edge collision, or emergency obstacle identified by lidar, the current task is immediately interrupted and the corresponding safety protection mechanism (such as emergency stop, audible and visual alarm) is triggered.

[0025] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. For those skilled in the art, any obvious changes such as equivalent transformations or simple substitutions based on the technical solutions of the present invention, without departing from the spirit and scope of the present invention, are within the protection scope of the present invention.

Claims

1. An electrical control system for an omnidirectional unmanned counterbalance forklift, characterized in that, include: The main control module runs the robot operating system and is used for overall task scheduling, path planning, and decision control. The gantry control module is communicatively connected to the main control module and is used to control the lifting, lateral movement, and tilting actions of the gantry. The chassis control module is communicatively connected to the main control module and is used to control the omnidirectional movement of the four steering wheels of the forklift. Sensor modules are used for environmental perception and forklift status detection; The communication module is used for data communication between modules and wireless communication with external systems. The power supply module is used to supply power to each module.

2. The electrical control system of the omnidirectional unmanned counterbalance forklift according to claim 1, characterized in that: The main control module uses an LPB3588 controller; the gantry control module uses a CPU1214 programmable logic controller; and the chassis control module uses an SRC-2000 motion controller.

3. The electrical control system of the omnidirectional unmanned counterbalance forklift according to claim 1, characterized in that: The main control module communicates with the gantry control module via TCP / IP Ethernet, and the main control module communicates with the chassis control module via CAN bus.

4. The electrical control system of the omnidirectional unmanned counterbalance forklift according to claim 1, characterized in that: The chassis control module is connected to the drive motor and steering motor via a CAN bus to control the four omnidirectional steering wheels to achieve omnidirectional movement of the forklift.

5. The electrical control system of the omnidirectional unmanned counterbalance forklift according to claim 1, characterized in that: The sensor module includes a lidar, a recognition camera, a photoelectric switch, and a wire encoder; The lidar is a 360-degree rotating scanning lidar, installed on the top and side of the forklift, used for mapping, positioning and obstacle avoidance; The recognition camera is a binocular vision camera, installed in the middle of the mast, used for fork recognition, pallet recognition and obstacle recognition; The photoelectric switch is installed on the mast and the fork tip to detect the height limit position and the fork position. The pull-wire encoder is installed at the lifting, lateral, and tilting points of the gantry to accurately measure the gantry position information.

6. The electrical control system of the omnidirectional unmanned counterbalance forklift according to claim 1, characterized in that: It also includes a safety protection module, which is connected to the sensor module and the main control module, for emergency braking, obstacle warning and system fault diagnosis.

7. The electrical control system of the omnidirectional unmanned counterbalance forklift according to claim 6, characterized in that, The safety protection module includes: an emergency stop button connected to the main control module; an audible and visual alarm for alarming abnormal conditions; and anti-collision contact edges for safety detection and emergency stopping.

8. The electrical control system of the omnidirectional unmanned counterbalance forklift according to claim 1, characterized in that, The robot operating system deployed in the main control module includes: a navigation function package for SLAM mapping and path planning; a control function package for motion control and gantry control; a perception function package for processing sensor data; and a communication function package for communication between modules.

9. The electrical control system of the omnidirectional unmanned counterbalance forklift according to any one of claims 1-8, characterized in that: It also includes a human-computer interaction module, which includes a touch screen and indicator lights for parameter setting, status display and fault alarm.

10. A control method for the electrical control system of an omnidirectional unmanned counterbalance forklift according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Environmental and State Perception: The sensor module acquires real-time information about the surrounding environment and the forklift's own status. S2, Task Planning and Decision-Making: Based on the tasks issued by the upper-level scheduling system and the information collected by S1, the main control module performs global path planning and real-time decision-making to generate the chassis motion path and gantry action sequence. S3, Chassis Omnidirectional Movement Control: The chassis control module receives path instructions from the main control module and drives four omnidirectional steering wheels through a closed-loop control algorithm, enabling the forklift to move precisely along the planned path. S4. Precision motion control of the gantry: The gantry control module receives the work instructions issued by the main control module, controls the hydraulic system to drive the gantry to complete the specified lifting, lateral movement or tilting actions, and realizes closed-loop position control through encoder feedback; S5. Security Monitoring and Protection: Throughout the operation, the safety protection module continuously monitors the system status; once an abnormal situation such as emergency stop triggering, edge collision, or emergency obstacle identified by lidar is detected, the current task is immediately interrupted and the corresponding safety protection mechanism is triggered.

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