CN117382721A - Wire control steering system and control method of wide mining dump truck - Google Patents

Abstract

The invention discloses a drive-by-wire steering system of a wide mining dump truck, which comprises a whole vehicle controller, a steering wheel angle sensor, a front axle wheel angle sensor, a rear axle wheel angle sensor, a hydraulic system and a steering control valve, wherein the whole vehicle controller receives driving intention transmitted by a driver through the steering wheel angle sensor, simultaneously receives analog signals of the angle sensors arranged on front and rear wheels, converts the signals into electric signals internally, calculates corresponding actual steering angles, adjusts the opening of the steering control valve through PID, controls a steering cylinder through a hydraulic oil way, enables the front wheel and the rear wheel to rotate according to the corresponding angles, achieves the cooperation of the front wheel and the rear wheel, achieves corresponding steering functions, combines a corresponding control method, effectively solves the problem of large vehicle flexibility, provides a key technology for unmanned driving in the intelligent mine field, and achieves one difficult problem of intelligent driving and unmanned driving in mining areas.

Description

A steering-by-wire system and control method for a wide-body mining dump truck

Technical field

The invention relates to the technical field of mining truck control, specifically a steering-by-wire system and control method for a wide-body mining dump truck.

Background technique

The off-highway wide-body dump truck is a heavy-duty dump truck used in open-pit mines to complete rock and earthwork stripping and ore transportation tasks. Its working characteristics are short transportation distance and heavy load. It is commonly used for loading with large electric shovels or hydraulic shovels, and travels to and from Mining and unloading points. China's mining dump truck industry originated in the early 1970s. After 2000, with the rapid demand and growth in the demand for heavy-duty dump trucks in China's mines, dump truck engineering machinery manufacturers have invested in the mining dump truck market. At present, the mainstream models produced in China are mainly concentrated in payloads of less than 100 tons. With the expansion of domestic large-scale open-pit mines of more than 10 million tons and the requirements for environmental protection and greenness, the demand for large-tonnage and ultra-large-tonnage mining dump trucks of more than 100 tons is increasing.

On the other hand, most of the roads in mining areas are temporary pavements, with narrow loading and unloading sites and frequent turns and reverses. There are many ups and downs and sharp turns in mountainous areas. In order to maintain maneuverability, large-tonnage and ultra-large-tonnage mining dump trucks are required. In other words, we must strive to reduce the turning radius and the number of reversing, so as to well adapt to the requirements of complex road surfaces and improve transportation efficiency. At the same time, with the rapid development of intelligence today, the smart steering-by-wire system is also the most important and most difficult issue to achieve intelligent driving and driverless driving in mining areas.

The present invention came into being under this environmental background. The control strategy of the present invention is to apply the front and rear axle dual steering systems through linear control to 100-200-ton and 200-300-ton wide-body mines: that is, an effective solution It improves the flexibility of large-tonnage vehicles and provides key technologies for the implementation of unmanned driving in the field of smart mining.

Contents of the invention

The purpose of the present invention is to provide a steering-by-wire system and control method for a wide-body mining dump truck, so as to solve the problem of lack of flexibility of current wide-body and large-tonnage vehicles raised in the above-mentioned background technology, and provide a solution for unmanned driving in smart mines. It provides key technologies for implementation in the field, which is a difficult problem to overcome in realizing intelligent driving and driverless driving in mining areas.

In order to achieve the above objects, the present invention provides the following technical solution: a wire-controlled steering system for a wide-body mining dump truck, including: a vehicle controller, a steering wheel angle sensor, a front axle wheel angle sensor, a rear axle wheel angle sensor, and a hydraulic steering system. system and steering control valve. The vehicle controller receives the driver's driving intention conveyed through the steering wheel angle sensor, and at the same time receives the analog signals from the angle sensors installed on the front and rear wheels, converts them internally into electrical signals, and calculates the corresponding actual steering angle. , and adjust the opening of the steering control valve through PID, and control the steering cylinder through the hydraulic oil circuit, so that the front wheels and rear wheels rotate according to the corresponding angles, so as to achieve the coordination of the front and rear wheels and achieve the corresponding steering function.

As a preferred technical solution, the rear axle of the wide-body mining dump truck is equipped with a two-position three-way hydraulic valve. The hydraulic valve is connected to two oil cylinders. The rear axle and the frame are connected by a slewing support structure. The two The oil cylinders are respectively arranged on both sides of the slewing support structure. When the oil cylinders contact the bearings, they can rotate, thereby realizing independent steering of the rear wheels.

As a preferred technical solution, both the front axle wheel angle sensor and the rear axle wheel angle sensor are non-contact angle sensors. The non-contact angle sensor includes a magnet end installed on the body and a sensor installed on the steering axle. The main body, through mechanical coupling, recognizes the rotation angle when its axle rotates, and sends it to the vehicle controller through electrical signals.

A wire-by-wire steering control method for a wide-body mining dump truck, including the following steps:

Step S1: The vehicle controller receives the electrical signal sent by the sensor and performs a series of internal preprocessing to obtain the actual angle value of the sensor;

Step S2: Calculate the target value angle of the front and rear axles based on the vehicle status, steering wheel angle, and corresponding body angle;

Step S3: Perform PID control operation based on the target value angle and the actual angle feedback value;

Step S4: The vehicle controller calculates the PWM value based on the PID output value and the input characteristics of the steering solenoid valve and outputs control to the front and rear axle steering solenoid valves to control left and right steering.

As a preferred technical solution, the preprocessing in step S1 includes filtering, data type conversion, and AD conversion.

As a preferred technical solution, in step S3, the PID control operation is performed according to the following rules:

1) Calculate and query the angle correspondence table according to the steering wheel angle to obtain the steering angle required by the first bridge. According to the value of the front axle wheel angle sensor, obtain the actual steering angle of the first bridge after data processing. Calculate the difference between the two. The difference is regular Turn the solenoid valve left, if the difference is negative, turn the solenoid valve right;

2) Calculate and query the angle correspondence table according to the steering wheel angle to obtain the steering angle required by the fourth axle. According to the value of the rear axle wheel angle sensor, obtain the actual steering angle of the fourth axle through data processing. Calculate the difference between the two. The difference is regular Turn the solenoid valve left, and if the difference is negative, turn the solenoid valve right.

As a preferred technical solution, the angle correspondence table is determined through prior calibration.

As a preferred technical solution, the vehicle controller is preset with a fault-tolerant algorithm to improve the redundancy of the entire system. When some devices fail, real-time data sampling is used to locate the fault type and location, and the remaining normally working components are integrated. devices work together to achieve normal working conditions. .

Compared with the prior art, the beneficial effects of the present invention are:

1) The steer-by-wire system effectively realizes the synchronization between the steering system and the steering wheel, thereby making the driver more sensitive in controlling the car; the steer-by-wire system eliminates the mechanical structure between the steering wheel and the steering wheel, making The mass of the steering system is reduced, which is conducive to the lightweight of the entire vehicle; the steer-by-wire system only needs to work when turning, which not only effectively increases the transmission efficiency, but also makes fuel more economical and environmentally friendly. The most important thing is that the steer-by-wire system The system uses front and rear axle steering, which greatly reduces the turning radius.

2) The sensor collects the relationship between the target angle and the actual angle, processes the signal, and controls the actuator according to the corresponding relationship. The use of this conventional sensor can make it a relatively mature product in the existing market, and it is easy to maintain later, but it has Different from traditional steering systems, the control strategy of this invention also has the following advantages: sensor signal filtering to improve accuracy; sensor fault diagnosis and fault handling; according to the actual left and right turn of the vehicle and the steering angle of the wide-body mining truck. The number of turns can be calibrated; when the vehicle is powered on, the current position of the steering wheel can be calibrated based on the real-time position of the wheels; redundant processing is performed after the rotation angle exceeds the maximum angle of the vehicle body.

Description of the drawings

Figure 1 is a control flow chart of the steering system of the present invention;

Figure 2 is an internal control strategy model of the controller of the present invention;

Figure 3 is an analysis diagram of factors affecting the turning radius of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

The invention provides a technical solution: a wire-controlled steering system for a wide-body mining dump truck, including: a vehicle controller, a steering wheel angle sensor, a front axle wheel angle sensor, a rear axle wheel angle sensor, a hydraulic system and a steering control valve, the vehicle controller receives the driver's driving intention conveyed through the steering wheel angle sensor, and at the same time receives the analog signals from the angle sensors installed on the front and rear wheels, converts them internally into electrical signals, calculates the corresponding actual steering angle, and uses the PID Adjust the opening of the steering control valve and control the steering cylinder through the hydraulic oil circuit, so that the front and rear wheels rotate at corresponding angles to achieve synergy between the front and rear wheels and achieve corresponding steering functions.

As a preferred technical solution, the rear axle of the wide-body mining dump truck is equipped with a two-position three-way hydraulic valve. The hydraulic valve is connected to two oil cylinders. The rear axle and the frame are connected by a slewing support structure. The two The oil cylinders are respectively arranged on both sides of the slewing support structure. When the oil cylinders contact the bearings, they can rotate, thereby realizing independent steering of the rear wheels. Both the front axle wheel angle sensor and the rear axle wheel angle sensor are non-contact angle sensors. The non-contact angle sensor includes a magnet end installed on the vehicle body and a sensor body installed on the steering axle. Through mechanical coupling, the vehicle The bridge recognizes the rotation angle when it rotates and sends it to the vehicle controller through an electrical signal.

The control-by-wire system is for hydraulically steered vehicles. Both the front and rear axles can achieve steering through the hydraulic system. The hardware system includes the vehicle controller, steering wheel angle sensor, front axle wheel angle sensor, rear axle wheel angle sensor, hydraulic system and steering control valve.

When the driver conveys his driving intention through the steering wheel angle sensor, the sensor transmits the signal to the controller through the CAN bus, and at the same time receives the analog signals from the front and rear wheel angle sensors, converts them internally into electrical signals, calculates the actual angle, and the controller adjusts the steering through PID The opening of the control valve controls the steering cylinder through the hydraulic oil circuit, so that the front and rear wheels rotate at corresponding angles to achieve synergy between the front and rear wheels, reduce the steering radius as much as possible, and achieve the steering function the driver wants to achieve. The flow chart is shown in Figure 1.

In this steering system, not only traditional front-wheel steering is used, but also rear-wheel active steering is used; general models are steered by the front wheels, while the rear wheels are fixed. Very few cars can do this except for the front wheels. The wheels can turn outward, and the rear wheels can also assist in linked steering. The steer-by-wire system of the present invention can achieve active steering of the rear wheels. The rear wheel steering system mode is reverse steering, which means that the rotation direction of the rear wheels is opposite to that of the front wheels. This mode can reduce the turning radius of the vehicle and better adapt to the complex temporary roads in the mining area.

The turning radius of a car means that theoretically all four wheels can turn around the same point. At this time, this point is the center of the wheel's turning trajectory, and the turning radius is the length from the rotation point to the outside wheel.

If we want to reduce the turning radius of a car, the main methods are: increasing the steering angle of the front wheels, reducing the wheelbase of the front and rear wheels, or reducing the left and right wheelbases. In the vehicle design process, these parameters are crucial because they are affected by the vehicle space and layout space. The range that can be adjusted is very small. Therefore, if the steering angle of the rear wheels can be changed at this time, even if the angle is relatively small, the steering radius of the entire vehicle will be greatly improved. In the past, this solution was used on some luxury cars with long wheelbases. Rear-wheel steering was generally used to improve the vehicle's flexibility by reducing the turning radius. However, it is not suitable for high-speed driving. However, our mine dump trucks generally do not travel at high speeds, and the road surface in mining areas requires high turning radius. This rear axle steering scheme is perfectly suitable.

The vehicle controller uses the current mainstream VCU controller, which can receive signals from sensors and implement analog-to-digital conversion; it can build a control algorithm model according to needs and automatically generate software codes to achieve more precise control. The entire steering system control strategy of the present invention is built and developed on the vehicle controller.

The internal control strategy model of the controller is shown in Figure 2. This control strategy model has two major characteristics:

1. Collect the relationship between the target angle and the actual angle through the sensor and process the signal:

The steering system of the present invention uses conventional angle sensors on the market: the steering wheel angle sensor can measure an angle change of about ±1560° after zero calibration: the steering column passes through the sensor, and when the driver turns the steering wheel, the angle sensor recognizes When the angle changes, the angle information and rotation speed are sent to the vehicle controller through CAN. Both the front axle wheel sensor and the rear axle wheel sensor can use the non-contact angle sensor shown in Figure 2: the sensor consists of two parts, the magnet end and the sensor body are respectively installed on the body and steering axle. Through mechanical coupling, the axle The rotation angle is recognized during rotation and sent to the vehicle controller through an electrical signal.

The use of this conventional sensor can make it a relatively mature product in the existing market and facilitate later maintenance. However, unlike traditional steering systems, the control strategy of this invention can achieve:

1) Filter the sensor signal to improve accuracy;

2) Sensor fault diagnosis and troubleshooting;

3) Calibration can be carried out based on how many degrees the actual vehicle can turn left and right and the number of turns of the wide-body mining truck steering wheel;

4) When the vehicle is powered on, the current position of the steering wheel can be calibrated based on the real-time position of the wheels;

5) Redundant processing after the rotation angle exceeds the maximum angle of the vehicle body.

2. Control the execution components according to the corresponding relationship

The vehicle controller hydraulic system and the steering control valve realize the vehicle steering principle: the vehicle controller controls the magnet coil to be energized to control the movement of the valve body; the structure of the hydraulic solenoid valve is shown in Figure 3. There is a sealed cavity in the hydraulic solenoid valve. There are through holes at different positions, and each hole is connected to a different oil pipe. There is a piston in the middle of the cavity, and two electromagnets on both sides. The valve body will be attracted to which side the magnet coil is energized. By controlling the movement of the valve body, Open or close different oil drain holes, and the oil inlet hole is always open. The hydraulic oil will enter the different oil drain pipes, and then push the piston of the oil cylinder through the pressure of the oil. The piston drives the piston rod, and the piston rod drives the mechanical device. , in this way, by controlling the current on and off of the electromagnet, the mechanical movement of the cylinder is controlled, and the axle is pushed to achieve steering.

In the present invention, the vehicle controller controls the mechanical movement of the oil cylinder by controlling the switch of the solenoid valve. The control method of the present invention can achieve: 1. According to the angle feedback value and calculated demand value, combined with the PID control valve opening, precise and rapid control Steering angle, 2. Combined with the characteristics of the solenoid valve, accurately control the minimum value that can drive the solenoid valve action.

Steering system diagnostic system: Nowadays, the safety and reliability of the wire-controlled steering system need to be improved, so fault diagnosis and processing must be done well. Types of faults that may occur in the steering-by-wire system: 1. Short circuits, open circuits and mechanical failures in the sensors have a greater impact on the system, but their occurrence frequency is not high; 2. Failures that have a greater impact on the system are poor contact and open circuits in the connectors. , bus initialization fault, bus sending timeout fault, bus receiving timeout fault, etc., and the faults with higher frequency are mainly due to poor connector contact. Although the frequency of signal mixing is higher, the impact on the system is low.

The current fault tolerance methods for faults are: relying on the fault tolerance algorithm of the controller to increase the redundancy of the entire system, thereby improving the fault tolerance performance of the system; when some devices fail, real-time data sampling is used to locate the fault type and location, and the remaining normal faults are integrated The working devices work together to achieve normal working conditions:

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principles and spirit of the invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (8)

1. A steering-by-wire system for a wide-body mining dump truck, which is characterized by including: a vehicle controller, a steering wheel angle sensor, a front axle wheel angle sensor, a rear axle wheel angle sensor, a hydraulic system and a steering control valve, The vehicle controller receives the driver's driving intention conveyed through the steering wheel angle sensor, and at the same time receives the analog signals from the angle sensors installed on the front and rear wheels, converts them internally into electrical signals, calculates the corresponding actual steering angle, and adjusts the steering through PID The opening of the control valve controls the steering cylinder through the hydraulic oil circuit, so that the front and rear wheels rotate at corresponding angles to achieve synergy between the front and rear wheels and achieve corresponding steering functions. 2. A wire-controlled steering system for a wide-body mining dump truck according to claim 1, characterized in that the rear axle of the wide-body mining dump truck is provided with a two-position three-way hydraulic valve, and the hydraulic valve is connected to Two oil cylinders, the rear axle and the frame are connected by a slewing support structure. The two oil cylinders are respectively arranged on both sides of the slewing support structure. The oil cylinders can rotate by contacting the bearings, thereby achieving independent steering of the rear wheels. 3. A steering-by-wire system for a wide-body mining dump truck according to claim 1, characterized in that both the front axle wheel angle sensor and the rear axle wheel angle sensor are non-contact angle sensors, and the non-contact The angle sensor includes a magnet end installed on the body and a sensor body installed on the steering axle. Through mechanical coupling, the axle recognizes the rotation angle when it rotates, and sends an electrical signal to the vehicle controller. 4. A steering-by-wire control method for a wide-body mining dump truck, which is characterized by including the following steps: Step S1: The vehicle controller receives the electrical signal sent by the sensor and performs a series of internal preprocessing to obtain the actual angle value of the sensor; Step S2: Calculate the target value angle of the front and rear axles based on the vehicle status, steering wheel angle, and corresponding body angle; Step S3: Perform PID control operation based on the target value angle and the actual angle feedback value; Step S4: The vehicle controller calculates the PWM value based on the PID output value and the input characteristics of the steering solenoid valve and outputs control to the front and rear axle steering solenoid valves to control left and right steering. 5. A steering-by-wire control method for a wide-body mining dump truck according to claim 4, characterized in that the preprocessing in step S1 includes filtering, data type conversion, and AD conversion. 6. A steering-by-wire control method for a wide-body mining dump truck according to claim 4, characterized in that in step S3, PID control calculations are performed according to the following rules: 1) Calculate and query the angle correspondence table according to the steering wheel angle to obtain the steering angle required by the first bridge. According to the value of the front axle wheel angle sensor, obtain the actual steering angle of the first bridge after data processing. Calculate the difference between the two. The difference is regular Turn the solenoid valve left, if the difference is negative, turn the solenoid valve right; 2) Calculate and query the angle correspondence table according to the steering wheel angle to obtain the steering angle required by the fourth axle. According to the value of the rear axle wheel angle sensor, obtain the actual steering angle of the fourth axle through data processing. Calculate the difference between the two. The difference is regular Turn the solenoid valve left, and if the difference is negative, turn the solenoid valve right. 7. A steering-by-wire control method for a wide-body mining dump truck according to claim 4, characterized in that the angle correspondence table is determined through prior calibration. 8. A steering-by-wire control method for a wide-body mining dump truck according to claim 4, characterized in that: a fault-tolerant algorithm is preset in the vehicle controller to improve the redundancy of the entire system, When some devices fail, real-time data sampling is used to locate the fault type and location, and the remaining normally working devices are integrated to work together to achieve normal working status.