Mining dump truck steer-by-wire control system based on state machine

Abstract

A mining dump truck steer-by-wire control system based on a state machine comprises the following steps that (1) a steering controller SCU receives data of a sensor and a vehicle control unit VCU through a sensor data processing layer and a CAN message analysis layer; (2) the steering controller SCU integrates the input data in the first step and submits the input data to a fault processing layer for screening; (3) the input data and the fault data are integrated and submitted to a state machine module for working mode switching; (4) the steering controller SCU executes the control strategy of the current steering mode, and calculation and output are carried out; (5) the output control layer sends output data to an execution mechanism to drive a steering wheel; and (6) the steering controller SCU feeds back the state information of the current system to a CAN message coding layer for message coding through a state feedback layer, and finally sends the state information to a vehicle control unit VCU.

Description

Technical Field

[0001] The present invention relates to the technical field of dump trucks, and in particular to a wire-controlled steering control system for mining dump trucks based on a state machine. Background Art

[0002] Traditional steering systems for mining dump trucks are mostly mechanical steering, hydraulic power steering, etc. Such steering system modes are single and do not require mode switching.

[0003] With the improvement of the automation and intelligence level of mining dump trucks, manned wire-controlled steering and even unmanned wire-controlled steering have been developed. The wire-controlled steering system needs to flexibly switch between different working modes to adapt to complex working environments.

[0004] Currently, most of the steering systems of mining dump trucks are non-wire-controlled steering. The control logic of non-wire-controlled steering is that the driver provides the desired steering angle, speed and torque through the steering wheel, and the corresponding steering force is obtained through the mechanical / hydraulic / electric control system to drive the steering gear to complete the steering.

[0005] Disadvantages of the existing technology: a. There is a mechanical connection between the steering wheel and the steering gear, which occupies a large space and has a high maintenance cost; b. The communication interface between the steering system and the VCU is simple, and the information interaction ability and security are insufficient, making it difficult to implement software algorithm optimization; c. The steering action is initiated by the driver and assisted by the steering gear, which can only adapt to manned driving, has a single steering mode, and is difficult to adapt to the complex working conditions of mines. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a wire-controlled steering control system for mining dump trucks based on a state machine, which improves the response speed and stability of the steering system.

[0007] To solve the above technical problem, the technical solution of the present invention is: A wire-controlled steering control system for mining dump trucks based on a state machine, comprising: Sensor module: High-pressure filter signal switch: used to detect whether the steering filter is blocked, and is connected to the steering controller SCU through a DI signal; Steering pressure sensor: used to detect the steering oil pressure, and is connected to the controller through an AI signal; Steering controller SCU: The execution center of the steering system, which receives sensor signals and instructions from the vehicle controller VCU, and after setting the control logic and calculation, outputs control instructions to drive the actuator to act, so as to achieve the purpose of controlling the wheel steering; Vehicle controller VCU: Sends control instructions and vehicle status information to the steering controller SCU through the CAN bus, and receives the status information of the steering controller SCU; Actuator: It includes a steering proportional valve, an oil cylinder and a wheel. The proportional valve receives the PWM signal from the steering controller SCU to control the opening of the valve, thereby changing the flow rate of the steering hydraulic oil, and finally driving the wheel to turn through the steering cylinder; Power source: It includes a steering pump and an emergency steering pump. When the steering pump fails, the emergency steering pump is put into use as a safety redundancy. The power source is controlled by the vehicle controller VCU. The steering controller SCU sends a power source control command to the vehicle controller VCU through the CAN bus; Control method of the steering system, including the following steps: (1) The steering controller SCU receives the data from the sensors and the vehicle controller VCU through the sensor data processing layer and the CAN message parsing layer; (2) The steering controller SCU integrates the input data in the first step and submits it to the fault handling layer for screening; (3) The input data and the fault data are integrated and submitted to the state machine module for working mode switching; (4) The steering controller SCU executes the control strategy of the current steering mode and calculates the output; (5) The output control layer sends the output data to the actuator to drive the steering wheel; (6) The steering controller SCU feeds back the current system status information to the CAN message encoding layer through the status feedback layer for message encoding, and finally sends it to the vehicle controller VCU.

[0008] As an improvement, the CAN 2.0B bus is adopted to realize the bidirectional communication between the steering controller SCU and the vehicle controller VCU, including the following communication frames: EPS mode control frame for realizing the switching control of the steering mode, EPS reset control frame for realizing the system reset control, EPS calibration control frame for realizing the system calibration control, EPS corner control frame for realizing the precise control of the steering angle, and EPS status feedback frame for realizing the status monitoring of the steering system.

[0009] As an improvement, there is a non-by-wire mode for people: when the steering controller SCU starts, the steering system automatically switches to the non-by-wire mode for people. At this time, the steering system is in the non-by-wire mode, and the steering controller SCU does not participate in the vehicle steering process. The steering action is completely completed by the steering wheel and the steering gear.

[0010] As an improvement, there is a manned wire control mode: when the steering mode request signal in the VCU EPS_MODE_CTRL communication frame is set to "manned wire control", the steering controller SCU will switch the working mode of the steering system to the manned wire control mode when the switching conditions of the state machine are met. The specific process of vehicle steering at this time is as follows: the driver turns the steering wheel, the steering sensor SASA collects the steering wheel speed, the steering controller SCU receives the steering wheel speed and processes and calculates it, the steering controller SCU controls the steering proportional valve according to the steering wheel speed and direction, the steering cylinder acts, and the wheels turn; in this mode, by changing the relationship between the steering wheel speed and the proportional valve opening, variable steering ratio of the vehicle is achieved.

[0011] As an improvement, there is an unmanned wire control mode: when the steering system is in the manned non-wire control or manned wire control mode, if the steering mode request signal in the VCU EPS_MODE_CTRL communication frame is set to "unmanned wire control", the steering controller SCU will switch the working mode of the steering system to the unmanned wire control mode when the switching conditions of the state machine are met. At this time, the steering controller SCU enters the preparation mode before automatic steering, the steering proportional valve opens a certain opening to enter the working ready state, the vehicle maintains the current steering angle, and the steering wheel does not move.

[0012] As an improvement, there is an automatic steering mode: when the steering system is in the unmanned wire control mode, if the steering angle enable signal in the VCU EPS_ANGLE_CTRL communication frame is set to "enabled", the steering controller SCU will switch the working mode of the steering system to the automatic steering mode when the switching conditions of the state machine are met. The difference between this mode and the unmanned wire control mode is that the steering system will automatically complete the steering action according to the "steering angle" signal in the EPS_ANGLE_CTRL communication frame, and the driver does not need to participate in the steering process.

[0013] As an improvement, there is a manual takeover mode: when the working mode of the steering system is in the unmanned wire control mode or the automatic steering mode, if the steering controller SCU detects that the steering wheel speed exceeds the set threshold, it will automatically switch to the manual takeover mode. At this time, the action process of the steering system is executed according to the manned wire control mode.

[0014] As an improvement, there is a safety mode: when the steering system is in any mode, when a secondary or tertiary fault of the steering controller SCU is triggered, the steering system will automatically switch to the safety mode, and the steering controller SCU will alarm. At this time, the action process of the steering system is executed according to the manned non-wire control mode.

[0015] As an improvement, during reset: when the steering system is in the safe mode and the secondary and tertiary faults of the steering controller SCU disappear, if the reset flag signal in the VCU EPS_RESET_CTRL communication frame is set to "enable", the steering system will automatically switch to the reset mode, the steering controller SCU will start to execute the reset process, and automatically switch to the manned non-wireless control mode after the reset process is completed.

[0016] As an improvement, calibration mode: when the steering system is in the manned non-wireless control mode, if the calibration request signal in the VCU EPS_CALIBRATE_CTRL communication frame is set to "request", the steering controller SCU will switch the working mode of the steering system to the calibration mode when the switching conditions of the state machine are met. At this time, the vehicle controller VCU can modify the steering parameters of the steering controller SCU through the relevant communication interfaces.

[0017] The beneficial effects brought by the present invention compared with the prior art are as follows: A standard communication interface with both real-time protection and safety design is proposed. Through the clear design of the control module hierarchy and the state machine, it can quickly, stably and reliably switch between different steering modes, improving the operation efficiency and safety of mining dump trucks. Description of the Drawings

[0018] Figure 1 It is the control topology diagram of the wire-controlled part of the steering system.

[0019] Figure 2 It is the communication interface diagram between the steering controller and the vehicle controller.

[0020] Figure 3 It is the control software module diagram of the steering system.

[0021] Figure 4 It is the control state machine diagram of the steering system. Detailed Embodiments

[0022] The present invention will be further described below with reference to the drawings of the specification.

[0023] As shown in Figure 1 A wire-controlled steering control system for mining dump trucks based on a state machine includes: Sensor module: High-pressure filter signal switch: used to detect whether the steering filter is blocked, connected to the steering controller SCU through a DI signal; Steering pressure sensor: used to detect the steering oil pressure, connected to the controller through an AI signal.

[0024] Steering Controller SCU: It is the execution center of the steering system. It receives sensor signals and instructions from the vehicle controller VCU, and after passing through the set control logic and calculations, outputs control instructions to drive the actuator to act, achieving the purpose of controlling the wheel steering.

[0025] Vehicle Controller VCU: Sends control instructions and vehicle status information to the steering controller SCU through the CAN bus, and receives the status information of the steering controller SCU.

[0026] Actuator: Includes a steering proportional valve, an oil cylinder, and a wheel. The proportional valve receives the PWM signal from the steering controller SCU to control the opening of the valve, thereby changing the flow rate of the steering hydraulic oil, and finally driving the wheel to steer through the steering cylinder.

[0027] Power source: Includes a steering pump and an emergency steering pump. When the steering pump fails, the emergency steering pump is put into use as a safety redundancy. The power source is controlled by the vehicle controller VCU, and the steering controller SCU sends power source control instructions to the vehicle controller VCU through the CAN bus.

[0028] As Figure 2 shown, the communication interface solution of the present invention uses the CAN 2.0B bus to achieve two-way communication between the steering controller SCU and the vehicle controller VCU, including the following communication frames: a. EPS Mode Control Frame (EPS_MODE_CTRL) Function: Realize the switching control of the steering mode Contains information: Steering mode request (used to switch different steering modes) Message serial number (ensuring communication reliability) Check value (guaranteeing data integrity).

[0029] b. EPS Reset Control Frame (EPS_RESET_CTRL) Function: Realize the system reset control Contains information: Reset flag (triggering the system reset) Check value (guaranteeing data integrity).

[0030] c. EPS Calibration Control Frame (EPS_CALIBRATE_CTRL) Function: Realize the system calibration control Contains information: Calibration request (triggering the system to enter / exit the calibration mode) Check value (guaranteeing data integrity).

[0031] d. EPS Angle Control Frame (EPS_ANGLE_CTRL) Function: Achieve precise control of the steering angle Contained information: Steering angle (target steering angle value) Steering angle enable (control instruction effective flag) Message serial number (ensure communication reliability) Check value (guarantee data integrity).

[0032] e.EPS status feedback frame (EPS_INFO) Function: Achieve steering system status monitoring Contained information: Current mode of SCU (feedback current working status) Error code (fault diagnosis information) Message serial number (ensure communication reliability) Check value (guarantee data integrity).

[0033] The communication interface of the present invention has the following advantages: 1. Real-time guarantee: Adopt CAN 2.0B bus to ensure the real-time and reliability of communication; for important key communication frames, adopt the message serial number loop technology mechanism to detect communication interruption and ensure the timing of control instructions; 2. Security: Each communication frame adopts CRC check value to ensure the accuracy of data transmission; adopt the error code feedback mechanism to achieve timely detection and handling of faults; 3. Mode switching protection: Through the cooperation of the mode control frame and the status feedback frame, ensure the reliability of mode switching; adopt the reset control mechanism to provide the emergency handling ability in case of system abnormality.

[0034] As Figure 3 shown, the control method of the steering system of the present invention includes the following steps: (1) The steering controller SCU receives the data of the sensor and the vehicle controller VCU through the sensor data processing layer and the CAN message parsing layer; (2) The steering controller SCU integrates the input data of the first step and submits it to the fault handling layer for screening; (3) Integrate the input data and the fault data and submit them to the state machine module for working mode switching; (4) The steering controller SCU executes the control strategy of the current steering mode and calculates the output; (5) The output control layer sends the output data to the actuator to drive the steering wheel; (6) The steering controller SCU feeds back the current system status information to the CAN message encoding layer through the status feedback layer for message encoding, and finally sends it to the vehicle controller VCU.

[0035] As Figure 4 shown, the state machine of the steering system includes the following modes: Manual non-wire-controlled mode: When the steering controller SCU is started, the steering system automatically switches to the manual non-wire-controlled mode. At this time, the steering system is in the non-wire-controlled mode, and the steering controller SCU does not participate in the vehicle steering process. The steering action is completely completed by the steering wheel and the steering gear.

[0036] Manual wire-controlled mode: When the steering mode request signal in the VCU EPS_MODE_CTRL communication frame is set to "manual wire-controlled", the steering controller SCU will switch the working mode of the steering system to the manual wire-controlled mode when the switching conditions of the state machine are met. The specific process of vehicle steering at this time is as follows: The driver turns the steering wheel, the steering sensor SASA collects the steering wheel speed, the steering controller SCU receives the steering wheel speed and processes and calculates it, the steering controller SCU controls the steering proportional valve according to the steering wheel speed and direction, the steering cylinder acts, and the wheels turn; in this mode, the variable steering ratio of the vehicle is achieved by changing the relationship between the steering wheel speed and the proportional valve opening.

[0037] Unmanned wire-controlled mode: When the steering system is in the manual non-wire-controlled or manual wire-controlled mode, if the steering mode request signal in the VCU EPS_MODE_CTRL communication frame is set to "unmanned wire-controlled", the steering controller SCU will switch the working mode of the steering system to the unmanned wire-controlled mode when the switching conditions of the state machine are met. At this time, the steering controller SCU enters the preparation mode before automatic steering, the steering proportional valve opens a certain opening to enter the working ready state, the vehicle maintains the current steering angle, and the steering wheels do not move.

[0038] Automatic steering mode: When the steering system is in the unmanned wire-controlled mode, if the steering angle enable signal in the VCU EPS_ANGLE_CTRL communication frame is set to "enabled", the steering controller SCU will switch the working mode of the steering system to the automatic steering mode when the switching conditions of the state machine are met. The difference between this mode and the unmanned wire-controlled mode is that the steering system will automatically complete the steering action according to the "steering angle" signal in the EPS_ANGLE_CTRL communication frame, and the driver does not need to participate in the steering process.

[0039] Manual takeover mode: When the working mode of the steering system is in the unmanned wire-controlled mode or the automatic steering mode, if the steering controller SCU detects that the steering wheel speed exceeds the set threshold, it will automatically switch to the manual takeover mode. At this time, the action process of the steering system is executed according to the manual wire-controlled mode.

[0040] Safe Mode: When the steering system is in any mode and a secondary or tertiary fault of the steering controller SCU is triggered, the steering system will automatically switch to the safe mode, and the steering controller SCU will alarm. At this time, the operation process of the steering system will be executed according to the non-wireless control mode for manned vehicles.

[0041] Resetting: When the steering system is in the safe mode and the secondary and tertiary faults of the steering controller SCU disappear, if the reset flag signal in the VCU EPS_RESET_CTRL communication frame is set to "enable", the steering system will automatically switch to the resetting mode. The steering controller SCU will start to execute the reset process and automatically switch to the non-wireless control mode for manned vehicles after the reset process is completed.

[0042] Calibration Mode: When the steering system is in the non-wireless control mode for manned vehicles, if the calibration request signal in the VCU EPS_CALIBRATE_CTRL communication frame is set to "request", the steering controller SCU will switch the working mode of the steering system to the calibration mode when the switching conditions of the state machine are met. At this time, the vehicle controller VCU can modify the steering parameters of the steering controller SCU through the relevant communication interfaces.

[0043] Features of the state machine of the present invention: 1. Clear mode switching conditions: Use control signals such as EPS_MODE_CTRL, EPS_ANGLE_CTRL, EPS_RESET_CTRL, EPS_CALIBRATE_CTRL, and steering sensors to achieve mode switching and steering angle adjustment; 2. Fault classification: The SCU adopts a three-level fault classification strategy. When the fault is secondary or tertiary, the safety mechanism is triggered; 3. Safety mechanism: When a secondary or tertiary fault of the system is detected, it will automatically switch to the safe mode to ensure vehicle safety.

Claims

1. A state machine-based steering-by-wire control system for a mining dump truck, characterized in that: include: Sensor module: High-pressure filter signal switch: used to detect whether the steering filter is blocked, connected to the steering controller SCU through the DI signal; Steering pressure sensor: used to detect the steering oil pressure, connected to the controller through the AI ​​signal; Steering controller SCU: The execution center of the steering system, which receives sensor signals and vehicle controller VCU instructions, outputs control instructions after set control logic and calculation, drives the actuator to act, and achieves the purpose of controlling wheel steering; Vehicle Controller VCU: sends control instructions and vehicle status information to the steering controller SCU through the CAN bus, and receives status information from the steering controller SCU; Actuator: includes steering proportional valve, oil cylinder and wheels. The proportional valve receives the PWM signal from the steering controller SCU to control the valve opening, thereby changing the flow rate of the steering hydraulic oil, and finally drives the wheel to steer through the steering cylinder; Power source: including steering pump and emergency steering pump. When the steering pump fails, the emergency steering pump is put into use as a safety redundancy. The power source is controlled by the vehicle controller VCU. The steering controller SCU sends power source control instructions to the vehicle controller VCU through the CAN bus; A control method for a steering system comprises the following steps: (1) The steering controller SCU receives data from sensors and the vehicle controller VCU through the sensor data processing layer and the CAN message parsing layer; (2) The steering controller SCU integrates the input data from the first step and submits it to the fault processing layer for screening; (3) Input data and fault data are integrated and submitted to the state machine module for working mode switching; (4) The steering controller SCU executes the control strategy of the current steering mode and calculates the output; (5) The output control layer sends the output data to the actuator to drive the steering wheel; (6) The steering controller SCU feeds back the current system status information to the CAN message encoding layer through the state feedback layer for message encoding, and finally sends it to the vehicle controller VCU.

2. A state machine-based steering-by-wire control system for a mining dump truck according to claim 1, characterized in that: The CAN 2.0B bus is used to realize two-way communication between the steering controller SCU and the vehicle controller VCU, including the following communication frames: EPS mode control frame for realizing steering mode switching control, EPS reset control frame for realizing system reset control, EPS calibration control frame for realizing system calibration control, EPS angle control frame for realizing precise control of steering angle, and EPS status feedback frame for realizing steering system status monitoring.

3. According to the state machine-based steering-by-wire control system for a mining dump truck according to claim 1, it is characterized in that: Manned non-wire control mode: When the steering controller SCU is started, the steering system automatically switches to the manned non-wire control mode. At this time, the steering system is in non-wire control mode. The steering controller SCU does not participate in the vehicle steering process, and the steering action is completely completed by the steering wheel and steering gear.

4. A state machine-based steering-by-wire control system for a mining dump truck according to claim 1, characterized in that: Manned by-wire mode: When the steering mode request signal of the VCU EPS_MODE_CTRL communication frame is set to "manned by-wire", the steering controller SCU will switch the working mode of the steering system to manned by-wire mode when the switching conditions of the state machine are met. At this time, the specific process of vehicle steering is: the driver turns the steering wheel, the steering sensor SASA collects the steering wheel speed, the steering controller SCU receives the steering wheel speed and processes and calculates it, and the steering controller SCU controls the steering proportional valve according to the steering wheel speed and direction, the steering cylinder moves, and the wheels steer; In this mode, the vehicle's variable steering ratio is achieved by changing the relationship between the steering wheel speed and the proportional valve opening.

5. The state machine-based steering-by-wire control system for a mining dump truck according to claim 1, characterized in that: Unmanned by-wire mode: When the steering system is in manned non-by-wire mode or manned by-wire mode, if the steering mode request signal of the VCU EPS_MODE_CTRL communication frame is set to "unmanned by-wire", the steering controller SCU will switch the working mode of the steering system to unmanned by-wire mode when the switching conditions of the state machine are met. At this time, the steering controller SCU enters the preparation mode before automatic steering, the steering proportional valve opens a certain degree and enters the working ready state, the vehicle maintains the current steering angle, and the steering wheel does not move.

6. The state machine-based steering-by-wire control system for a mining dump truck according to claim 1, characterized in that: Automatic steering mode: When the steering system is in the unmanned drive-by-wire mode, if the steering angle enable signal of the VCU EPS_ANGLE_CTRL communication frame is set to "enable", the steering controller SCU will switch the steering system's working mode to automatic steering mode when the switching conditions of the state machine are met. The difference between this mode and the unmanned drive-by-wire mode is that the steering system will automatically complete the steering action according to the "steering angle" signal of the EPS_ANGLE_CTRL communication frame, and the steering process does not require the driver to participate.

7. The state machine-based steering-by-wire control system for a mining dump truck according to claim 1, characterized in that: Manual takeover mode: When the steering system is in the unmanned wire control mode or automatic steering mode, if the steering controller SCU detects that the steering wheel speed exceeds the set threshold, it will automatically switch to the manual takeover mode. At this time, the steering system's action process is executed according to the manned wire control mode.

8. The state machine-based steering-by-wire control system for a mining dump truck according to claim 1, characterized in that: Safety mode: When the steering system is in any mode and a level 2 fault or level 3 fault of the steering controller SCU is triggered, the steering system will automatically switch to safety mode and the steering controller SCU will alarm. At this time, the steering system's action flow is executed in the manned non-wire control mode.

9. The state machine-based steering-by-wire control system for a mining dump truck according to claim 1, characterized in that: Resetting: When the steering system is in safety mode and the secondary and tertiary faults of the steering controller SCU disappear, if the reset flag signal of the VCUEPS_RESET_CTRL communication frame is set to "enable", the steering system will automatically enter the resetting mode, the steering controller SCU will start the reset process, and automatically enter the manned non-wire control mode after the reset process is completed.

10. The state machine-based steering-by-wire control system for a mining dump truck according to claim 1, characterized in that: Calibration mode: When the steering system is in manned non-wire control mode, if the calibration request signal of the VCU EPS_CALIBRATE_CTRL communication frame is set to "request", the steering controller SCU will switch the working mode of the steering system to the calibration mode when the switching conditions of the state machine are met. At this time, the vehicle controller VCU can modify the steering parameters of the steering controller SCU through the relevant communication interface.

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