Safety control system for electric fork lift truck

Abstract

The utility model discloses a kind of safety control systems for electric fork-lift truck, including battery module, motor controller module, DC-DC module, domain controller module, fork-lift truck goods weight and lifting height detection module and fork-lift truck obstacle detection module, the signal output end of fork-lift truck goods weight and lifting height detection module and the signal output end of fork-lift truck obstacle detection module are connected with the signal input end of domain controller module respectively, the signal output end of domain controller module is connected with the signal input end of motor controller module, the signal output end of motor controller module is externally connected with the traction motor for controlling fork-lift truck operation by speed encoder.The utility model carries out centralized processing to vehicle operation data and environmental perception data by introducing domain controller, simplifies the wiring harness arrangement and hardware configuration of traditional multiple ECU distributed architecture, reduces system cost and fault point, improves the initiative safety and operation reliability of electric fork-lift truck.

Description

Technical Field

[0001] This utility model relates to the field of forklift technology, and in particular to a safety control system for electric forklifts. Background Technology

[0002] As a key material handling equipment in modern logistics and industrial production, the operational safety of electric forklifts is of paramount importance. With the development of electronic technology, the safety systems of mainstream electric forklifts have evolved from early purely mechanical or relay-controlled systems to an architecture based on distributed electronic control units (ECUs). Under this architecture, the vehicle is equipped with various dedicated sensors and actuators, forming several relatively independent safety subsystems. These distributed ECUs exchange basic data via a CAN bus, forming a "one function, one box" solution. Each ECU focuses on its specific task, possessing an independent microprocessor and control logic.

[0003] However, this traditional distributed architecture is gradually revealing its inherent technical bottlenecks when dealing with increasingly complex security requirements: (1) The communication bandwidth between each ECU is limited, and there is a lack of a powerful central processing unit for global information fusion, which results in safety functions being limited to simple "single-point trigger" responses. For example, when the collision avoidance system detects an obstacle, it can only issue an alarm or perform emergency braking, and cannot coordinate the alarm and deceleration of the entire vehicle. (2) A large number of ECUs means that a complex wiring harness network is needed for connection and power supply. This not only increases material costs and vehicle weight, but also leads to an increase in connectors, potential failure points, and reduced system reliability. Utility Model Content

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to propose a safety control system for electric forklifts. By introducing a domain controller to centrally process vehicle operation data and environmental perception data, it simplifies the wiring harness layout and hardware configuration of the traditional multi-ECU distributed architecture, reduces system costs and potential failure points, and improves the active safety and operational reliability of the electric forklift.

[0005] A safety control system for an electric forklift, according to this utility model, includes a battery module, a motor controller module, a DC-DC module, a domain controller module, a forklift cargo weight and lifting height detection module, and a forklift obstacle detection module. The output terminal of the battery module is connected to the power input terminals of the motor controller module and the DC-DC module. The output terminal of the DC-DC module is connected to the power input terminals of the domain controller module, the forklift cargo weight and lifting height detection module, and the forklift obstacle detection module. The signal output terminals of the forklift cargo weight and lifting height detection module and the forklift obstacle detection module are connected to the signal input terminal of the domain controller module. The signal output terminal of the domain controller module is connected to the signal input terminal of the motor controller module. The signal output terminal of the motor controller module is connected to a traction motor via a speed encoder. The traction motor receives signals from the motor controller to drive the forklift. The speed encoder feeds back the real-time operating speed of the traction motor to the motor controller.

[0006] Preferably, the battery module includes a lithium battery, the motor controller module includes a motor controller, and the DC-DC module includes a DC-DC converter. The first positive output of the lithium battery is connected to the B+ port of the motor controller and the positive input port of the DC-DC converter via a switch MR. The second positive output of the lithium battery is connected to the enable control terminal C of the DC-DC converter, the key port of the motor controller, and the main contactor port via an emergency stop switch and a key switch, respectively. A main contactor coil is provided on the branch connecting the main contactor port of the motor controller to the positive terminal of the lithium battery. A main contactor switch is provided on the branch connecting the B+ port of the motor controller to the positive terminal of the lithium battery. The B- port of the DC-DC converter and the B- port of the motor controller are both connected to the negative terminal of the lithium battery.

[0007] Preferably, the domain controller module includes a domain controller, the forklift obstacle detection module includes a sensing camera for detecting obstacles in front of and behind the forklift and a millimeter-wave radar for detecting the distance between the rear obstacle and the forklift, the positive output terminal of the DC-DC converter is connected to the power input terminal of the domain controller, the power input terminal of the sensing camera and the power input terminal of the millimeter-wave radar respectively, the signal output terminal of the sensing camera and the signal output terminal of the millimeter-wave radar are connected to the signal input terminal of the domain controller respectively, the domain controller is connected to the motor controller via a CAN bus, and the negative output terminal of the domain controller is connected to the negative terminal of the lithium battery.

[0008] Preferably, the forklift cargo weight and lifting height detection module includes a load cell for detecting the real-time weight of the forks and a pull-rope sensor for detecting the real-time height of the forks. The power input terminals of the load cell and the pull-rope sensor are respectively connected to the positive output terminal of the DC-DC converter, and the signal output terminals of the load cell and the pull-rope sensor are respectively connected to the signal input terminal of the domain controller.

[0009] Preferably, the signal output terminal of the domain controller is further connected to an external warning device, the signal output terminal of the domain controller is connected to the signal input terminal of the warning device, and the signal output terminal of the warning device is connected to the negative terminal of the lithium battery.

[0010] Preferably, the system further includes a driver identification module, the power input terminal of which is connected to the positive output terminal of the DC-DC converter, the signal output terminal of which is connected to the signal input terminal of the domain controller, the signal output terminal of the domain controller being connected to an identification relay coil, the signal output terminal of the domain controller being connected to the negative terminal of the lithium battery via the identification relay coil, and the second positive output of the lithium battery being connected to the identification relay port of the motor controller via an emergency stop switch, a key switch, and an identification relay switch in sequence.

[0011] Preferably, the driver identification module includes a face recognition submodule, a password activation submodule, a fingerprint recognition submodule, and a card swipe activation submodule. The power input terminals of the face recognition submodule, the password activation submodule, the fingerprint recognition submodule, and the card swipe activation submodule are respectively connected to the positive output terminal of the DC-DC converter. The signal output terminals of the face recognition submodule, the password activation submodule, the fingerprint recognition submodule, and the card swipe activation submodule are respectively connected to the signal input terminal of the domain controller.

[0012] Preferably, the battery module has a battery management subsystem.

[0013] The beneficial effects of this invention are as follows: By introducing a domain controller module into the system, multiple signals from various sources, including the forklift cargo weight and lifting height detection module, obstacle detection module, motor controller module, and driver identification module, are uniformly connected to the domain controller. The domain controller centrally processes vehicle operation data and environmental perception data. Compared to the traditional distributed architecture of "one ECU per function," this significantly reduces the number of independent control units and wiring harness connection points, optimizes the overall vehicle wiring harness layout and hardware configuration, thereby reducing material costs and potential failure points, and improving system integration and long-term operational reliability. Secondly, by using load cells and pull rope sensors to collect fork load weight and lifting height in real time, and simultaneously inputting obstacle information collected by sensing cameras and millimeter-wave radar into the domain controller, the domain controller can comprehensively judge and intervene in dangerous working conditions such as overload lifting, speeding, and reversing in narrow passages under a unified control logic. Combined with the motor controller to limit the output torque of the traction motor and vehicle speed, and the audible and visual alarms of the warning device, this achieves a shift from single-point response to multi-factor linkage active safety control, effectively improving the electric forklift's anti-collision and anti-tipping capabilities under complex working conditions. Attached Figure Description

[0014] In the attached diagram: Figure 1 This is a circuit diagram of a safety control system for an electric forklift proposed in this utility model. Detailed Implementation

[0015] Reference Figure 1 A safety control system for an electric forklift includes a battery module, a motor controller module, a DC-DC module, a domain controller module, a forklift cargo weight and lifting height detection module, and a forklift obstacle detection module. The output terminal of the battery module is connected to the power input terminals of the motor controller module and the DC-DC module, respectively. The output terminal of the DC-DC module is connected to the power input terminals of the domain controller module, the forklift cargo weight and lifting height detection module, and the forklift obstacle detection module, respectively. The signal output terminals of the forklift cargo weight and lifting height detection module and the forklift obstacle detection module are connected to the signal input terminals of the domain controller module, respectively. The signal output terminal of the domain controller module is connected to the signal input terminal of the motor controller module. The signal output terminal of the motor controller module is externally connected to a traction motor for controlling the operation of the forklift via a speed encoder.

[0016] Clearly, based on the above: the battery module provides main power to the motor controller module and the DC-DC module, which in turn provides stable operating power to the domain controller module, the forklift load weight and lifting height detection module, and the forklift obstacle detection module. During forklift operation, the forklift load weight and lifting height detection module collects real-time fork load and lifting height information, while the forklift obstacle detection module collects information on obstacles in front of and behind the vehicle. These signals are then sent to the domain controller module, which comprehensively assesses the load status, lifting conditions, and surrounding environment before outputting control commands to the motor controller module. The motor controller module then adjusts the traction motor output based on feedback from the speed encoder. This achieves coordinated control of the electric forklift's operating status under different loads and lifting heights, reducing the risk of misoperation in hazardous conditions, improving the overall safety and stability of the vehicle, and facilitating centralized management of power and signals, simplifying system wiring and module configuration.

[0017] In this embodiment, the battery module includes a lithium battery, the motor controller module includes a motor controller, and the DC-DC module includes a DC-DC converter. The first positive output of the lithium battery is connected to the B+ port of the motor controller and the positive input port of the DC-DC converter via a switch MR. The second positive output of the lithium battery is connected to the enable control terminal C of the DC-DC converter, the key port of the motor controller, and the main contactor port via an emergency stop switch and a key switch, respectively. A main contactor coil is provided on the branch connecting the main contactor port of the motor controller to the positive terminal of the lithium battery. A main contactor switch is provided on the branch connecting the B+ port of the motor controller to the positive terminal of the lithium battery. The B- port of the DC-DC converter and the B- port of the motor controller are both connected to the negative terminal of the lithium battery.

[0018] Clearly, based on the above, lithium batteries can directly power the motor controller and the DC-DC converter, which then converts the voltage to facilitate power supply to subsequent electrical appliances.

[0019] In this embodiment, the domain controller module includes a domain controller, a forklift obstacle detection module for sensing cameras to detect obstacles in front of and behind the forklift, and a millimeter-wave radar for detecting the distance between the rear obstacle and the forklift. The positive output terminal of the DC-DC converter is connected to the power input terminal of the domain controller, the power input terminal of the sensing camera, and the power input terminal of the millimeter-wave radar, respectively. The signal output terminals of the sensing camera and the millimeter-wave radar are connected to the signal input terminal of the domain controller, respectively. The domain controller is connected to the motor controller via a CAN bus, and the negative output terminal of the domain controller is connected to the negative terminal of the lithium battery.

[0020] Specifically, there are three sets of sensing cameras, one each at the front left, front right, and rear of the overhead guard; and two sets of millimeter-wave radar, one set each at the rear of the forklift counterweight and on the left and right sides.

[0021] Clearly, based on the above: the sensing cameras acquire real-time images of the front left, front right, and rear areas of the overhead guard, while the millimeter-wave radar continuously measures the distance to obstacles on the left and right sides behind the forklift's counterweight. The image and distance information are then output to the domain controller, which comprehensively analyzes and identifies the multi-source sensor data. Based on the obstacle's location, distance changes, and the forklift's operating conditions, corresponding control commands are generated and sent to the motor controller via the CAN bus to implement safety controls such as speed limiting, braking, or alarms. This embodiment achieves three-dimensional coverage perception of the forklift's front, rear, and rear sides without significantly increasing wiring complexity, effectively reducing the driver's blind spot, improving obstacle detection coverage and accuracy, and enabling fast and reliable communication between the domain controller and motor controller via the CAN bus. This significantly enhances the electric forklift's active safety protection capabilities and operational safety during reversing, turning, and operation in narrow passages.

[0022] In this embodiment, the forklift cargo weight and lifting height detection module includes a load cell for detecting the real-time weight of the forks and a pull rope sensor for detecting the real-time height of the forks. The power input terminals of the load cell and the pull rope sensor are respectively connected to the positive output terminal of the DC-DC converter, and the signal output terminals of the load cell and the pull rope sensor are respectively connected to the signal input terminal of the domain controller.

[0023] Specifically, the load cells are installed on the mast crossbeam of the forklift, one on each side of the crossbeam; the main body of the pull rope sensor is installed on the mast, and the extended pull rope head is connected to the fork. As the fork is raised, the pull rope head is driven to rise to detect the height of the fork. Clearly, based on the above: the load cells sense the weight carried by the forks in real time, while the drawstring sensor, connected to the forks, extends and retracts synchronously with the forks as they rise and fall, continuously detecting the real-time lifting height of the forks. The load and height signals are then synchronously input into the domain controller, which identifies and controls operating conditions such as overload lifting, high-speed lifting without load, and high-position driving based on preset load and height thresholds. Through the symmetrical arrangement of the load cells and the direct linkage between the drawstring sensor and the forks, this embodiment can accurately obtain the force state and lifting position of the forks, avoiding errors and lags caused by single-point detection or discrete detection by limit switches. This facilitates continuous monitoring and dynamic intervention of the fork lifting process, thereby improving the accuracy and timeliness of overload warnings and high-position speed limit control, and significantly enhancing the safety and stability of the electric forklift during cargo handling.

[0024] In this embodiment, the signal output terminal of the domain controller is also connected to an external alarm device. The signal output terminal of the domain controller is connected to the signal input terminal of the alarm device, and the signal output terminal of the alarm device is connected to the negative terminal of the lithium battery.

[0025] Specifically, the warning device is located slightly above the rear of the overhead guard. The warning device includes a buzzer, horn, warning light, etc. It receives instructions from the controller and transmits vehicle status information to the operator and surrounding personnel by emitting a specific combination of sound and light signals.

[0026] Clearly, based on the above: after comprehensively calculating the forklift load status, lifting height, travel speed, and obstacle information, the domain controller outputs corresponding control signals to the warning device according to the current operating status. The buzzer, horn, and warning light in the warning device operate according to a preset sound and light combination, timely and intuitively conveying the vehicle status under different working conditions such as speeding, overloading, and approaching obstacles to the operator and surrounding personnel. By uniformly driving multiple sound and light elements through the domain controller, this embodiment can achieve differentiated prompts according to the risk level, improving the recognizability and delivery efficiency of warning information, avoiding the problems of delayed or insufficiently conspicuous prompts caused by relying solely on a single indicator light or mechanical sign, thereby helping to reduce the probability of misoperation and collision accidents, and further improving the operational safety of electric forklifts under complex working conditions.

[0027] In this embodiment, a driver identification module is also included. The power input terminal of the driver identification module is connected to the positive output terminal of the DC-DC converter. The signal output terminal of the driver identification module is connected to the signal input terminal of the domain controller. The signal output terminal of the domain controller is also connected to an identification relay coil. The signal output terminal of the domain controller is connected to the negative terminal of the lithium battery through the identification relay coil. The second positive output of the lithium battery is also connected to the identification relay port of the motor controller in sequence through an emergency stop switch, a key switch, and an identification relay switch.

[0028] Obviously, based on the above: after the forklift is powered on, the identity of the person boarding is verified, and the identification result is sent to the domain controller in the form of a signal. When the domain controller confirms that the driver's identity is legitimate and other system safety conditions are met, it drives the identity recognition relay coil to operate, thus connecting the control circuit formed by the second path of the lithium battery positive terminal through the emergency stop switch, key switch, and identity recognition relay switch. This sends a valid control signal to the identity recognition relay port of the motor controller, allowing the motor controller to enter a working state where the vehicle can be driven. If the driver identification fails or the domain controller detects an abnormal operating condition, the identity recognition relay coil remains de-energized, blocking the aforementioned control circuit. Even if the emergency stop switch and key switch are in the on state, the motor controller still cannot obtain start authorization. By hardware-cascading the driver identification result with the enable logic of the motor controller, this embodiment implements an access control mechanism of "the entire vehicle cannot be driven if the identity is not verified," effectively preventing unauthorized personnel from starting the vehicle, reducing the risk of misoperation and illegal driving, and improving the management safety and controllability of the electric forklift's operation.

[0029] In this embodiment, the driver identification module includes a face recognition submodule, a password activation submodule, a fingerprint recognition submodule, and a card swipe activation submodule. The power input terminals of the face recognition submodule, the password activation submodule, the fingerprint recognition submodule, and the card swipe activation submodule are respectively connected to the positive output terminal of the DC-DC converter. The signal output terminals of the face recognition submodule, the password activation submodule, the fingerprint recognition submodule, and the card swipe activation submodule are respectively connected to the signal input terminal of the domain controller.

[0030] Specifically, the face recognition submodule is located on the right front leg of the overhead guard; the password activation submodule is located on the left side of the dashboard; the fingerprint recognition submodule is located on the left front leg of the overhead guard; and the card swipe activation submodule is located on the right side of the dashboard. Obviously, based on the above, integrating multiple identity verification methods (face, fingerprint, card swipe, password) into the domain controller allows users to choose the verification method according to their needs, providing personalized options.

[0031] In this embodiment, the battery module has a battery management subsystem.

[0032] Clearly, based on the above, the battery management subsystem can be configured to monitor the status of the forklift battery and protect it.

[0033] To more clearly illustrate the implementation plan and its effects, we will use the attached diagram as an example: Please refer to Figure 1When the key switch is closed, the electric forklift is not yet fully powered on; identity verification is required before the vehicle can be powered on. There are four verification methods available: facial recognition start, card swipe start, password start, and fingerprint verification start. The driver can choose any method for verification. After successful verification, the domain controller energizes the identity recognition relay coil, which in turn closes the identity recognition relay switch connected to the motor controller, allowing the motor to operate normally and the vehicle to enter the operational state.

[0034] Overspeed alarm: During normal driving, the motor controller outputs current to the traction motor to make the motor rotate. The speed encoder detects the motor speed and feeds it back to the motor controller in real time. The controller calculates the real-time vehicle speed V and compares it with the preset speed limit V. limit Comparison: If the real-time vehicle speed V > V limit At this time, the forklift is in an overspeeding state. The motor controller feeds back to the domain controller via the CAN bus. The domain controller then sends a command to the warning device, triggering an audible and visual alarm to inform the driver that the forklift is speeding.

[0035] Lifting height interlock control: A pull rope sensor monitors the fork height H in real time. A safe height H is preset within the domain controller. max When H>H max At this time, the domain controller controls the warning device to trigger the audible and visual alarms, and sends instructions to the motor controller via the CAN bus to limit the vehicle's maximum speed to a very low value (such as 3 km / h) to ensure the forklift's driving safety when the forks are in a high position.

[0036] Active Collision Avoidance Warning: Sensing cameras installed on the overhead guards at the left front, right front, and rear of the forklift continuously monitor the surrounding environment. When any camera detects an obstacle entering the first-level warning distance, the domain controller activates a warning device that emits an intermittent buzzer and flashes a yellow light to alert the driver. When the obstacle enters the second-level braking distance, the alarm escalates to a rapid buzzer and flashing red light. Simultaneously, the domain controller calculates the vehicle's deceleration curve by combining the real-time fork height detected by the pull rope sensor and the fork weight detected by the load cell, and sends a deceleration command to the motor controller via the CAN bus to force the vehicle to slow down. When an obstacle enters a dangerous distance, the domain controller can send a braking command to force the vehicle to stop. When the vehicle is engaged in reverse gear, two millimeter-wave radars mounted on the rear counterweight begin operating. When an obstacle is detected, feedback is sent to the domain controller, which further activates the warning device to issue an alarm, informing the driver to ensure safe reversing.

Claims

1. A safety control system for electric forklifts, characterized in that: The system includes a battery module, a motor controller module, a DC-DC module, a domain controller module, a forklift cargo weight and lifting height detection module, and a forklift obstacle detection module. The output of the battery module is connected to the power input of the motor controller module and the DC-DC module. The output of the DC-DC module is connected to the power input of the domain controller module, the forklift cargo weight and lifting height detection module, and the forklift obstacle detection module. The signal outputs of the forklift cargo weight and lifting height detection module and the forklift obstacle detection module are connected to the signal input of the domain controller module. The signal output of the domain controller module is connected to the signal input of the motor controller module. The signal output of the motor controller module is connected to an external traction motor via a speed encoder. The traction motor receives signals from the motor controller to drive the forklift. The speed encoder feeds back the real-time operating speed of the traction motor to the motor controller.

2. A safety control system for an electric forklift according to claim 1, characterized in that: The battery module includes a lithium battery, the motor controller module includes a motor controller, and the DC-DC module includes a DC-DC converter. The first positive output of the lithium battery is connected to the B+ port of the motor controller and the positive input port of the DC-DC converter via a switch MR. The second positive output of the lithium battery is connected to the enable control terminal C of the DC-DC converter, the key port of the motor controller, and the main contactor port via an emergency stop switch and a key switch, respectively. A main contactor coil is provided on the branch connecting the main contactor port of the motor controller to the positive terminal of the lithium battery. A main contactor switch is provided on the branch connecting the B+ port of the motor controller to the positive terminal of the lithium battery. The B- port of the DC-DC converter and the B- port of the motor controller are both connected to the negative terminal of the lithium battery.

3. A safety control system for an electric forklift according to claim 2, characterized in that: The domain controller module includes a domain controller. The forklift obstacle detection module is a sensing camera for detecting obstacles in front of and behind the forklift and a millimeter-wave radar for detecting the distance between the rear obstacle and the forklift. The positive output terminal of the DC-DC converter is connected to the power input terminal of the domain controller, the power input terminal of the sensing camera, and the power input terminal of the millimeter-wave radar, respectively. The signal output terminals of the sensing camera and the millimeter-wave radar are connected to the signal input terminal of the domain controller, respectively. The domain controller is connected to the motor controller via a CAN bus, and the negative output terminal of the domain controller is connected to the negative terminal of the lithium battery.

4. A safety control system for an electric forklift according to claim 3, characterized in that: The forklift cargo weight and lifting height detection module includes a load cell for detecting the real-time weight of the forks and a pull-rope sensor for detecting the real-time height of the forks. The power input terminals of the load cell and the pull-rope sensor are respectively connected to the positive output terminal of the DC-DC converter. The signal output terminals of the load cell and the pull-rope sensor are respectively connected to the signal input terminal of the domain controller.

5. A safety control system for an electric forklift according to claim 3, characterized in that: The domain controller's signal output terminal is also connected to an external warning device. The domain controller's signal output terminal is connected to the warning device's signal input terminal, and the warning device's signal output terminal is connected to the negative terminal of the lithium battery.

6. A safety control system for an electric forklift according to claim 3, characterized in that: It also includes a driver identification module, the power input terminal of which is connected to the positive output terminal of the DC-DC converter, the signal output terminal of which is connected to the signal input terminal of the domain controller, the signal output terminal of the domain controller is also connected to an identification relay coil, the signal output terminal of the domain controller is connected to the negative terminal of the lithium battery through the identification relay coil, and the second positive output of the lithium battery is also connected to the identification relay port of the motor controller in sequence through an emergency stop switch, a key switch and an identification relay switch.

7. A safety control system for an electric forklift according to claim 6, characterized in that: The driver identification module includes a face recognition submodule, a password activation submodule, a fingerprint recognition submodule, and a card swipe activation submodule. The power input terminals of the face recognition submodule, the password activation submodule, the fingerprint recognition submodule, and the card swipe activation submodule are respectively connected to the positive output terminal of the DC-DC converter. The signal output terminals of the face recognition submodule, the password activation submodule, the fingerprint recognition submodule, and the card swipe activation submodule are respectively connected to the signal input terminal of the domain controller.

8. A safety control system for an electric forklift according to claim 2, characterized in that: The battery module has a battery management subsystem inside.

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