A redundant communication loop structure for forklift instruments and multiple controllers

Abstract

This invention discloses a redundant communication loop structure for forklift instruments and multiple controllers, belonging to the field of forklift electrical control technology. Its core structure includes an instrument cluster, a vehicle control unit (VCU), a traction motor controller (MCU), an oil pump motor controller (HCU), a battery management system (BMS), and two independent CAN communication loops and a redundancy switching unit. Each core electrical component is equipped with dual independent CAN interfaces, respectively connected to the first CAN communication loop (main loop) and the second CAN communication loop (redundant hot standby loop). The redundancy switching unit monitors the main loop link status in real time, seamlessly switching to the redundant loop to complete core data interaction in case of a main loop failure. This invention features a simple structure, low modification cost, and achieves communication redundancy and fault tolerance between forklift instruments and multiple controllers, significantly improving the safety, reliability, and maintainability of the entire vehicle's electrical system, and is suitable for mass application in various forklift models.

Description

Technical Field

[0001] This invention belongs to the field of forklift electrical control technology, specifically a redundant communication loop structure for forklift instruments and multiple controllers. Background Technology

[0002] In forklift electrical control technology, the industry commonly uses a single-channel CAN bus architecture, where the instrument cluster and all core controllers are connected to the same CAN bus and communicate via a single set of twisted-pair shielded cables. This architecture suffers from the following unavoidable core defects under the complex operating conditions of forklifts: 1. Single point of failure leads to system-wide communication interruption: Forklifts operate in harsh environments, and wiring harnesses in the chassis and mast are prone to wear and breakage, loose connectors, water ingress and corrosion. When a single CAN bus experiences wiring harness failure, terminating resistor failure, or damage to the CAN interface of a certain node, the entire CAN bus will be completely paralyzed, the instrument assembly will lose connection with all controllers, and the instrument panel will directly show a black screen with no data displayed.

[0003] 2. Troubleshooting is difficult and after-sales costs are extremely high: After a single bus failure, after-sales personnel need to disassemble and inspect all bus nodes, wiring harnesses and connectors of the entire vehicle one by one in order to locate the fault point.

[0004] 3. Lack of redundancy and fault tolerance, and insufficient compliance: The existing single-path architecture lacks communication redundancy design. For high-risk special working conditions such as explosion-proof forklifts, cold storage forklifts, and port heavy-duty forklifts, it cannot meet the mandatory requirements for safety redundancy in the national special equipment safety standards, and there are regulatory compliance risks and safety hazards.

[0005] Therefore, there is an urgent need to design a new type of forklift electrical control structure to solve the above-mentioned technical problems. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a solution to the problems of instrument disconnection, high safety risks, and difficulty in after-sales troubleshooting caused by single-channel CAN bus failure in existing forklifts.

[0007] To address the aforementioned technical problems, embodiments of the present invention provide the following technical solution: a redundant communication loop structure for a forklift instrument cluster and multiple controllers, comprising an instrument cluster assembly, a traction motor controller (MCU), an oil pump motor controller (HCU), a battery management system (BMS), a first CAN communication loop, a second CAN communication loop, and a redundancy switching unit; the instrument cluster assembly, traction motor controller (MCU), oil pump motor controller (HCU), and battery management system (BMS) each have built-in independent first CAN interface and second CAN interface; the first CAN communication loop is an independent twisted-pair shielded wire harness, electrically connected to the first CAN interface of each component, forming the vehicle's main communication bus; the second CAN communication loop is an independent twisted-pair shielded wire harness physically isolated from the first CAN communication loop, electrically connected to the second CAN interface of each component, forming the vehicle's redundant hot standby communication bus; the redundancy switching unit is electrically connected to the core control terminals of the instrument cluster assembly and the vehicle controller (VCU), used to monitor the link status of the first CAN communication loop in real time, and switch to the second CAN communication loop to complete core data interaction when the first CAN communication loop fails.

[0008] Furthermore, the redundancy switching unit includes a CAN link monitoring module and a hardware switching execution module; the signal acquisition terminal of the CAN link monitoring module is electrically connected to the bus terminals of the first CAN communication loop and the second CAN communication loop, respectively, for real-time acquisition of message heartbeat data, bus level data and error frame data of the two buses; the control input terminal of the hardware switching execution module is electrically connected to the signal output terminal of the CAN link monitoring module, and the signal output terminal of the hardware switching execution module is electrically connected to the two CAN interface enable terminals of the instrument assembly and the vehicle controller (VCU).

[0009] Furthermore, the CAN link monitoring module has a built-in bus fault diagnosis chip, and the hardware switching execution module has a built-in hardware comparison circuit and MOS transistor switch array. The switching action of the hardware switching execution module is triggered by a hardware level signal.

[0010] Furthermore, the wiring harnesses of the first CAN communication circuit and the second CAN communication circuit are respectively arranged in different body areas of the forklift; the first CAN communication circuit is integrated in the main wiring harness of the forklift chassis, and the second CAN communication circuit is integrated in the independent wiring harness of the forklift overhead guard. The two wiring harnesses have no parallel laying sections, no shared connectors, and no shared protective sleeves.

[0011] Furthermore, each end of the first CAN communication loop and the second CAN communication loop is provided with an independent terminating resistor. The terminating resistor values ​​of the two buses are both 120Ω, and the terminating resistors are respectively built into the corresponding CAN interface circuits of the instrument cluster and the vehicle controller VCU.

[0012] Furthermore, the instrument assembly has a built-in fault indication module. The input terminal of the fault indication module is electrically connected to the signal output terminal of the redundancy switching unit, and is used to display the working status and fault alarm information of the two CAN communication loops in real time.

[0013] Furthermore, it also includes an emergency stop interlocking unit. The signal output terminal of the emergency stop interlocking unit is electrically connected to the emergency stop signal node of the first CAN communication circuit and the second CAN communication circuit, respectively. The emergency stop trigger signal is synchronously transmitted to the instrument assembly, traction motor controller MCU, oil pump motor controller HCU, and battery management system BMS through the first CAN communication circuit and the second CAN communication circuit.

[0014] Furthermore, it also includes a dual-channel isolated power supply module, the output of which provides mutually isolated DC power to the interface circuits of the first CAN communication circuit and the second CAN communication circuit respectively.

[0015] The beneficial effects of the above-described technical solution of the present invention are as follows: The redundant communication circuit structure for forklift instruments and multiple controllers provided by this invention, through the setting of two physically isolated CAN communication circuits and a redundant switching unit, achieves seamless switching to the hot standby circuit in the event of a main circuit failure. This completely solves the problem of instrument blackouts and vehicle communication interruptions caused by single-point failures such as wiring harness wear and node damage on a single CAN bus. Independent wiring for dual circuits avoids common-cause failures, significantly improving the safety and reliability of the vehicle's electrical system. Simultaneously, the instrument's built-in fault indication module can locate faulty circuits in real time, reducing the difficulty and cost of after-sales troubleshooting. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the redundant communication loop structure between the forklift instrument and the multiple controllers of the present invention. Figure 2 This is a circuit diagram of the main circuit CAN link monitoring module chip of the present invention; Figure 3 This is a circuit diagram of the redundant loop CAN link monitoring module chip of the present invention; Figure 4 This is a schematic diagram of the fault level signal shaping circuit output by the CAN link monitoring module of the present invention.

[0017] Figure 5 This is a circuit diagram of the hardware switching execution module chip of the present invention. Detailed Implementation

[0018] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0019] like Figure 1 As shown, this invention proposes a redundant communication loop structure for a forklift instrument cluster and multiple controllers, including an instrument cluster assembly 3, a traction motor controller 1, an oil pump motor controller 2, a battery management system 4, a first CAN communication loop 5, a second CAN communication loop 6, and a redundancy switching unit. The instrument cluster assembly 3, traction motor controller 1, oil pump motor controller 2, and battery management system 4 each have built-in independent first CAN interface and second CAN interface. The first CAN communication loop 5 is an independent twisted-pair shielded wire harness, electrically connected to the first CAN interface of each component, forming the vehicle's main communication bus. The second CAN communication loop 6 is an independent twisted-pair shielded wire harness physically isolated from the first CAN communication loop, electrically connected to the second CAN interface of each component, forming the vehicle's redundant hot standby communication bus. The redundancy switching unit is electrically connected to the core control terminals of the instrument cluster assembly and the vehicle controller VCU, respectively, for real-time monitoring of the link status of the first CAN communication loop, and switching to the second CAN communication loop to complete core data interaction when the first CAN communication loop fails.

[0020] In this embodiment, the redundancy switching unit includes a CAN link monitoring module and a hardware switching execution module; the signal acquisition terminal of the CAN link monitoring module is electrically connected to the bus terminals of the first CAN communication loop and the second CAN communication loop, respectively, for real-time acquisition of message heartbeat data, bus level data, and error frame data of the two buses. Figure 2 , 3 The diagrams shown are the main loop CAN link monitoring module and the redundant loop CAN link monitoring module chip circuits, respectively. The TJA1044GTK chip is used, which is an integrated high-speed CAN transceiver with a built-in complete hardware-level bus fault diagnosis circuit. It can directly detect all common CAN bus faults, such as bus short circuit to power / ground, bus open circuit, missing terminating resistor, and node faults pulling the bus down. In case of a fault, a pure hardware level signal is output through the ERR pin, with a response time of <1μs, meeting real-time requirements. Figure 4 As shown, this is a dual-channel voltage comparator based on LM393DR, used to shape the fault level signal output by TJA1044, filter out electromagnetic interference in the industrial environment, and prevent false triggering.

[0021] The control input terminal of the hardware switching execution module is electrically connected to the signal output terminal of the CAN link monitoring module, and the signal output terminal of the hardware switching execution module is electrically connected to the enable terminals of the two CAN interfaces of the instrument cluster and the vehicle control unit (VCU). Figure 5The diagram shows the hardware switching execution module chip circuit diagram, which uses a TS5A23157 dual-channel SPDT analog switch with an on-resistance of only 0.5Ω and a switching time of 10ns. It can simultaneously switch the CANH and CANL channels of the CAN differential signal to ensure signal integrity. When the main circuit is normal, the ERR pin of U1 outputs a low level (<0.8V), the LM393 outputs a low level, and the COM terminal of the TS5A23157 is connected to the NO1 terminal, allowing the instrument to connect to the main CAN circuit. When the main circuit fails, the ERR pin of U1 outputs a high level (>2.8V), the LM393 outputs a high level, and the COM terminal of the TS5A23157 immediately switches to the NO2 terminal, allowing the instrument to seamlessly connect to the redundant CAN circuit.

[0022] In addition, the CAN link monitoring module has a built-in bus fault diagnosis chip, and the hardware switching execution module has a built-in hardware comparison circuit and MOSFET switch array. The switching action of the hardware switching execution module is triggered by a hardware level signal.

[0023] In this embodiment, the wiring harnesses of the first CAN communication circuit 5 and the second CAN communication circuit 6 are respectively arranged in different body areas of the forklift; the first CAN communication circuit is integrated into the main wiring harness of the forklift chassis, and the second CAN communication circuit is integrated into the independent wiring harness of the forklift overhead guard. The two wiring harnesses have no parallel laying sections, no shared connectors, and no shared protective sleeves. At the same time, each end of the first CAN communication circuit 5 and the second CAN communication circuit 6 is provided with an independent terminating resistor. The terminating resistor value of both buses is 120Ω, and the terminating resistors are respectively built into the corresponding CAN interface circuits of the instrument assembly and the vehicle controller VCU.

[0024] In this embodiment, the instrument assembly has a built-in fault indication module. The input terminal of the fault indication module is electrically connected to the signal output terminal of the redundancy switching unit, which is used to display the working status and fault alarm information of the two CAN communication loops in real time.

[0025] In this embodiment, an emergency stop interlocking unit is also included. The signal output terminal of the emergency stop interlocking unit is electrically connected to the emergency stop signal node of the first CAN communication circuit and the second CAN communication circuit, respectively. The emergency stop trigger signal is synchronously transmitted to the instrument assembly, traction motor controller MCU, oil pump motor controller HCU, and battery management system BMS through the first CAN communication circuit and the second CAN communication circuit.

[0026] In this embodiment, a dual-channel isolated power supply module is also included. The output terminals of the dual-channel isolated power supply module provide mutually isolated DC power to the interface circuits of the first CAN communication circuit and the second CAN communication circuit, respectively.

[0027] In summary, this invention establishes two physically isolated and electrically independent CAN communication loops (a main loop and a redundant hot standby loop) and utilizes a redundancy switching unit to monitor the link status of the main loop in real time. Under normal operating conditions, the instrument cluster and each controller complete all data interaction through the first CAN communication loop, while the second CAN communication loop is in hot standby mode. The CAN link monitoring module (TJA1044GTK chip) in the redundancy switching unit continuously collects message heartbeats, bus levels, and error frame data from the main loop. Once an anomaly such as a bus short circuit, open circuit, missing terminating resistor, or node failure is detected, its ERR pin immediately outputs a hardware level transition signal. After being shaped by a hardware comparator circuit, this signal drives the hardware switching execution module (TS5A23157 analog switch) to switch the CAN interface enable pins of the instrument cluster and each controller from the first loop to the second loop, achieving seamless redundant takeover. Meanwhile, the two buses share no physical paths or connectors, avoiding common-cause failures; emergency stop signals are transmitted synchronously through dual circuits, ensuring the redundancy of safety interlocks; the instrument's built-in fault indication module reports the circuit status in real time, facilitating rapid fault location. This all-hardware link monitoring and switching mechanism does not rely on software judgment, offering fast response and high reliability, fundamentally solving the communication interruption problem caused by single-channel CAN bus failures.

[0028] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A redundant communication loop structure for a forklift instrument and multiple controllers, characterized in that, The system includes an instrument cluster, a traction motor controller (MCU), an oil pump motor controller (HCU), a battery management system (BMS), a first CAN communication loop, a second CAN communication loop, and a redundancy switching unit. Each of these components has a built-in independent first CAN interface and a second CAN interface. The first CAN communication loop is an independent twisted-pair shielded wire harness, electrically connected to the first CAN interface of each component, forming the vehicle's main communication bus. The second CAN communication loop is an independent twisted-pair shielded wire harness physically isolated from the first CAN communication loop, electrically connected to the second CAN interface of each component, forming the vehicle's redundant hot standby communication bus. The redundancy switching unit is electrically connected to the core control terminals of the instrument cluster and the vehicle controller (VCU), used to monitor the link status of the first CAN communication loop in real time and switch to the second CAN communication loop to complete core data interaction when the first CAN communication loop fails.

2. The redundant communication loop structure between the forklift instrument and the multi-controller according to claim 1, characterized in that, The redundancy switching unit includes a CAN link monitoring module and a hardware switching execution module; the signal acquisition terminal of the CAN link monitoring module is electrically connected to the bus terminals of the first CAN communication loop and the second CAN communication loop respectively, and is used to collect the message heartbeat data, bus level data and error frame data of the two buses in real time. The control input terminal of the hardware switching execution module is electrically connected to the signal output terminal of the CAN link monitoring module, and the signal output terminal of the hardware switching execution module is electrically connected to the two CAN interface enable terminals of the instrument assembly and the vehicle controller (VCU).

3. The redundant communication loop structure between the forklift instrument and the multi-controller according to claim 2, characterized in that, The CAN link monitoring module has a built-in bus fault diagnosis chip, and the hardware switching execution module has a built-in hardware comparison circuit and MOS transistor switch array. The switching action of the hardware switching execution module is triggered by a hardware level signal.

4. The redundant communication loop structure between the forklift instrument and the multi-controller according to claim 1, characterized in that, The wiring harnesses for the first CAN communication circuit and the second CAN communication circuit are respectively arranged in different body areas of the forklift; the first CAN communication circuit is integrated into the main wiring harness of the forklift chassis, and the second CAN communication circuit is integrated into the independent wiring harness of the forklift overhead guard.

5. The redundant communication loop structure between the forklift instrument and the multi-controller according to claim 1, characterized in that, Both ends of the first CAN communication loop and the second CAN communication loop are respectively provided with independent terminating resistors, and the terminating resistors are respectively built into the corresponding CAN interface circuits of the instrument assembly and the vehicle controller VCU.

6. The redundant communication loop structure between the forklift instrument and the multi-controller according to claim 1, characterized in that, The instrument assembly has a built-in fault indication module. The input terminal of the fault indication module is electrically connected to the signal output terminal of the redundancy switching unit, and is used to display the working status and fault alarm information of the two CAN communication loops in real time.

7. The redundant communication loop structure between the forklift instrument and the multi-controller according to claim 1, characterized in that, It also includes an emergency stop interlocking unit, whose signal output terminal is electrically connected to the emergency stop signal node of the first CAN communication circuit and the second CAN communication circuit respectively. The emergency stop trigger signal is synchronously transmitted to the instrument assembly, traction motor controller MCU, oil pump motor controller HCU and battery management system BMS through the first CAN communication circuit and the second CAN communication circuit.

8. The redundant communication loop structure between the forklift instrument and the multi-controller according to claim 1, characterized in that, It also includes a dual-channel isolated power supply module, the output of which provides isolated DC power to the interface circuits of the first CAN communication circuit and the second CAN communication circuit respectively.

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