A kind of intelligent driving vehicle steering redundancy system and control method thereof

Abstract

The present application discloses a steering redundancy system and a control method for an intelligent driving vehicle, which relates to the field of vehicle automatic driving technology. The steering redundancy system includes an air suspension gas tank, two three-position three-way solenoid valves, and two actuating cylinders. The two three-position three-way solenoid valves are electrically connected to the automatic driving controller; the air suspension gas tank is divided into two branches, each of which is connected to the three-position three-way solenoid valve and the actuating cylinder in sequence through an air pipe; when the main steering system fails, or the main steering system is normal but the steering angle is insufficient, the automatic driving controller controls the switching of the two three-position three-way solenoid valves, so that one actuating cylinder is connected to the atmosphere through the air pipe, and the other actuating cylinder is connected to the air suspension gas tank through the air pipe. The steering redundancy system and the control method of the present application can assist in steering when the main steering system is normal; when the main steering system fails, it can perform normal low-speed driving, and can also respond quickly to achieve emergency pull-over parking.

Description

Technical Field

[0001] The present application relates to the field of vehicle autonomous driving technology, and in particular to a steering redundancy system for an intelligent driving vehicle and a control method thereof. Background Art

[0002] At present, the application of autonomous driving vehicles is becoming more and more widespread. Autonomous driving vehicles can sense obstacles, automatically turn, and brake at the right time. Specifically, an autonomous driving vehicle includes a steering system, a perception system, an autonomous driving controller, and a braking system. The perception system is responsible for sensing obstacles, the steering system is responsible for steering-related operations, the braking system is responsible for braking, and the autonomous driving controller is responsible for overall control and management. When the vehicle needs to turn, the autonomous driving controller sends a steering control request to the steering system, and the steering system is responsible for controlling the motor speed and torque, turning the wheels, and achieving the purpose of vehicle steering. However, when the steering system of an autonomous driving vehicle fails, especially during driving, the autonomous driving vehicle can generally only make an emergency stop, which can easily cause traffic congestion or traffic accidents, and there are huge safety hazards.

[0003] In the related art, in order to solve the above problems, those skilled in the art have proposed a steering failure response system, which is a technical solution that can perform emergency pull-over when the steering system fails. Specifically, a pneumatic system is added to the original autonomous driving vehicle, and when the steering system fails, the left and right front wheels are inflated and deflated to achieve the purpose of steering to the side.

[0004] However, the steering failure response system can only start working after the original steering system (hereinafter referred to as the main steering system) fails; and it can only be used for pulling over and parking, and cannot drive normally; if the main steering system fails in the wilderness, the driver will be trapped in the current situation, reducing the driving experience; at the same time, when the main steering system fails, the steering failure response system needs to first reduce the speed of the autonomous driving vehicle to a set value. The speed corresponding to the set value is extremely small, and the deceleration process takes a long time; only then can the left and right front wheels be inflated and deflated, and the vehicle can be pulled over. Steering is achieved by controlling the tire pressure. The speed of wheel inflation and deflation is relatively slow, and the system response is slow, which increases the danger to a certain extent. Summary of the invention

[0005] In view of the defects existing in the prior art, the purpose of this application is to provide a steering redundancy system and a control method for an intelligent driving vehicle, by adding a steering redundancy system, which can assist steering when the main steering system is normal; when the main steering system fails, it can carry out normal low-speed driving and can also respond quickly to achieve emergency pull-over parking.

[0006] In order to achieve the above purpose, the technical solution adopted is: a steering redundancy system for an intelligent driving vehicle, the steering redundancy system includes an air suspension air tank, two three-position three-way solenoid valves and two actuating cylinders; the side walls of the two actuating cylinders are fixed to the frame crossbeam body, and the active ends of the two actuating cylinders are respectively connected to two steering knuckles for installing wheels; the air suspension air tank is divided into two branches, and each branch is connected to the three-position three-way solenoid valve and the actuating cylinder in sequence through an air pipe; the steering redundancy system is used to switch the working positions of the two three-position three-way solenoid valves, change the connection or disconnection state of the air suspension air tank and the two actuating cylinders, and promote the steering of the left and right steering knuckles.

[0007] On the basis of the above technical solution, the three-position three-way solenoid valve comprises a first working position for connecting the actuating cylinder with the air suspension air tank, a second working position for cutting off the actuating cylinder with the air suspension air tank, and a third working position for closing the air pipe port on the air suspension air tank side and connecting the air pipe on the actuating cylinder side to the atmosphere;

[0008] When the main steering system fails, or the main steering system is normal but its steering angle is insufficient, one three-position three-way solenoid valve is in the third working position; the other three-position three-way solenoid valve is in the first working position, and its corresponding actuating cylinder pushes the corresponding steering knuckle to steer.

[0009] On the basis of the above technical solution, the intelligent driving vehicle further comprises a frame crossbeam assembly, the frame crossbeam assembly comprises a frame crossbeam body and two steering knuckles respectively hinged at both ends of the frame crossbeam body; the two steering knuckles are connected by a steering tie rod; the side walls of the two actuating cylinders are mounted on the frame crossbeam body, and the active ends of the actuating cylinders are fixed to the steering knuckles;

[0010] The actuating cylinder comprises a cylinder body, a piston head and a piston rod. The side wall of the cylinder body is fixed to the frame crossbeam body through a rod body and a ball joint, and the piston head of the actuating cylinder and the cylinder body form an air chamber, which is connected to a three-position three-way solenoid valve through an air pipe; the protruding end of the piston rod is connected to the steering knuckle through a ball joint and a connecting rod.

[0011] The present application also discloses a control method based on the above-mentioned steering redundancy system, wherein two three-position three-way solenoid valves are electrically connected to the automatic driving controller, and the control method comprises the following steps:

[0012] When the main steering system is normal but the steering angle is insufficient, the power steering process is executed; when the main steering system fails, the speed reduction process or the pull-over process is executed;

[0013] The power steering process, the deceleration driving process and the pull-over parking process include the same steering procedure, and the steering procedure includes the following steps:

[0014] The automatic driving controller controls the switching of two three-position three-way solenoid valves, so that one actuating cylinder is connected to the atmosphere through an air pipe, and the other actuating cylinder is connected to the air suspension air tank through an air pipe;

[0015] The air suspension air tank inflates the corresponding actuating cylinder, pushes the active end of the actuating cylinder to drive the corresponding steering knuckle to rotate, and then drives the other steering knuckle to rotate synchronously.

[0016] Based on the above technical solution, when the main steering system controls the steering knuckle to reach a limit steering angle but has not yet reached a target steering angle, the power steering process is executed to further increase the steering angle of the steering knuckle to the target steering angle.

[0017] On the basis of the above technical solution, the speed reduction driving process includes:

[0018] The steering redundancy system replaces the main steering system, and the braking system of the intelligent driving vehicle reduces the vehicle speed to the first set speed. The intelligent driving vehicle travels at a low speed within the first set speed range; when turning left or right, the steering program is executed;

[0019] The pull-over parking process includes:

[0020] The steering redundancy system replaces the main steering system, and the braking system of the intelligent driving vehicle reduces the vehicle speed to a second set speed, and pulls over to the side of the road by repeatedly executing the steering program; the second set speed is less than the first set speed.

[0021] On the basis of the above technical solution, the three-position three-way solenoid valve comprises a first working position for connecting the actuating cylinder with the air suspension air tank, a second working position for cutting off the actuating cylinder with the air suspension air tank, and a third working position for closing the air pipe port on the air suspension air tank side and connecting the air pipe on the actuating cylinder side to the atmosphere;

[0022] The steering procedure comprises the following steps:

[0023] The automatic driving controller controls a three-position three-way solenoid valve to be in the third working position, and the corresponding actuating cylinder is connected to the atmosphere through an air pipe; it controls another three-position three-way solenoid valve to be in the first working position, and the corresponding actuating cylinder is connected to the air suspension air tank through an air pipe.

[0024] On the basis of the above technical solution, the deceleration process of reducing the vehicle speed to the first set vehicle speed, and the pull-over process of reducing the vehicle speed to the second set vehicle speed both include:

[0025] The intelligent driving vehicle continues to travel along the predetermined trajectory. If the vehicle deviates from the trajectory, the automatic driving controller corrects the vehicle's motion trajectory to the predetermined trajectory by switching the working positions of two three-position three-way solenoid valves until the vehicle speed is reduced to the first set speed or the second set speed.

[0026] Based on the above technical solution, the pull-over parking process includes:

[0027] The automatic driving controller 1 determines whether the two front wheels are in the forward direction. If so, it proceeds to the next step; if not, it executes the steering program to control the two front wheels to return to the forward direction;

[0028] The perception system of the intelligent driving vehicle determines the parking direction, executes the steering program and controls the vehicle to turn in the parking direction; the vehicle continues to drive, and the perception system senses that the front of the vehicle deviates to the parking direction to the set lateral distance;

[0029] The steering program is executed and the vehicle is controlled to turn in the opposite direction of the parking direction; the vehicle continues to move, and the perception system senses that the vehicle body is parallel to the road edge and the vehicle stops.

[0030] On the basis of the above technical solution, the intelligent driving vehicle further comprises a frame crossbeam assembly, the frame crossbeam assembly comprises a frame crossbeam body and two steering knuckles respectively hinged at both ends of the frame crossbeam body, the two steering knuckles are connected by a steering tie rod; two actuating cylinders are mounted on the frame crossbeam body, and the active ends of the actuating cylinders are fixed to the steering knuckles;

[0031] The actuating cylinder comprises a cylinder body, a piston head and a piston rod. The side wall of the cylinder body is fixed to the frame crossbeam body through a rod body and a ball joint, and the piston head of the actuating cylinder and the cylinder body form an air chamber, which is connected to a three-position three-way solenoid valve through an air pipe; the protruding end of the piston rod is connected to the steering knuckle through a ball joint and a connecting rod.

[0032] The beneficial effects of the technical solution provided by this application include:

[0033] 1. The steering redundancy system of the present application can also work when the main steering system is normal. That is, in some special scenarios, when the steering angle of the main steering system is insufficient, the steering redundancy system can further steer on the basis of the main steering system and expand the steering angle, so that the steering angle of the intelligent driving vehicle is greater than that of a conventional vehicle, and the steering range is larger and more flexible. When the main steering system fails, the steering redundancy system replaces the main steering system to perform subsequent steering control, which allows both normal low-speed driving and pull-over parking. Compared with existing steering failure response systems, the steering redundancy system of the present application has wider functions and more applicable scenarios. At the same time, it uses two actuating cylinders to push the steering knuckle to steer the wheels. Compared with existing steering failure response systems that inflate and deflate the left and right front wheels, it has high control efficiency and fast response.

[0034] 2. The steering redundancy system of the present application is cleverly designed with two three-position three-way solenoid valves 4, and is controlled by the automatic driving controller 1. The combination of the three-position three-way solenoid valve 4 and the actuating cylinder 5 can satisfy the requirements of turning the wheel left, turning the wheel right and keeping the direction of the wheel unchanged (three basic requirements for steering). It is comprehensive in function, can assist in steering on the basis of the main steering system, and can take over the steering responsibility and drive normally at low speed when the main steering system fails, and can further respond quickly to pull-over parking.

[0035] 3. The control method of the steering redundancy system of the present application can execute the power steering process when the main steering system is normal but the steering angle is insufficient; when the main steering system fails, it can execute the speed reduction process or the pull-over parking process, and it is comprehensive in functionality; the key to the speed reduction process is that the sensitivity of the steering redundancy system of the present application is much higher than the reaction sensitivity of the left and right front wheels to inflate and deflate the air in the existing steering fault response system, which is also the main reason why the steering redundancy system of the present application can travel at a low speed within the first set vehicle speed range, while the existing steering fault response system cannot achieve low-speed driving.

[0036] The reason for the quick response of the pull-over parking process is that pull-over parking only requires reducing the vehicle speed to the second set speed and then performing an emergency pull-over parking; compared with the deceleration value of pull-over parking in the existing steering failure response system, the second set speed is larger, and the steering redundancy system of the present application can complete the deceleration in a shorter time and respond faster; further, the air suspension air tank drives the two steering knuckles to steer through two actuating cylinders. Compared with the left and right wheels of the existing steering failure response system that inflates and deflates air, the reaction sensitivity of the actuating cylinder is faster than the reaction sensitivity of the wheel inflating and deflation, and can respond quickly to achieve emergency pull-over parking, and can complete pull-over parking within a shorter forward distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 A schematic diagram of a steering redundancy system provided in an embodiment of the present application.

[0039] Figure numerals: 1. Automatic driving controller; 2. Air suspension air tank; 3. Frame crossbeam assembly; 4. Three-position three-way solenoid valve; 41. First working position; 42. Second working position; 43. Third working position; 5. Actuating cylinder; 51. Piston rod; 52. Piston head; 6. Ball joint; 7. Connecting rod; 8. Air pipe; 9. Atmosphere. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present application clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] like Figure 1 As shown, the present application discloses an embodiment of a steering redundancy system for an intelligent driving vehicle, wherein the intelligent driving vehicle includes a main steering system and an automatic driving controller 1.

[0042] The steering redundancy system includes an air suspension air tank 2, two three-position three-way solenoid valves 4 and two actuating cylinders 5. The air suspension air tank 2 provides high-pressure gas to the actuating cylinders 5. The two three-position three-way solenoid valves 4 are both electrically connected to the automatic driving controller 1, and the automatic driving controller 1 controls and adjusts the working positions of the two three-position three-way solenoid valves 4.

[0043] The two actuating cylinders 5 are fixed to the frame crossbeam body, and the movable ends of the two actuating cylinders 5 (i.e., the extended ends of the piston rods described later) are respectively connected to the steering knuckles for mounting the wheels. Steering knuckle steering is wheel steering. Specifically, the steering redundancy system controls the steering knuckle, and the wheel hub rotates around the axis of the steering knuckle. The air suspension air tank 2 is divided into two branches, each of which is connected to the three-position three-way solenoid valve 4 and the actuating cylinder 5 in sequence through the air pipe 8, and the two branches independently pneumatically control the steering of their respective wheels. Specifically, the wheel includes a tire and a wheel hub, and the wheel hub is mounted on the steering knuckle.

[0044] The steering redundancy system of the present application is used to switch the working positions of the two three-position three-way solenoid valves 4, change the connection or disconnection state between the air suspension air tank 2 and the two actuating cylinders 5, and promote the steering of the left and right steering knuckles.

[0045] Specifically, when the main steering system is normal, the automatic driving controller 1 controls the switching of two three-position three-way solenoid valves 4, so that both actuating cylinders 5 are connected to the atmosphere 9 through the air pipe 8. The main steering system works normally, and the actuating cylinders 5 of the steering redundancy system will not form resistance to wheel steering.

[0046] When the main steering system is normal but the steering angle is insufficient, and steering drive force is required, the steering redundancy system can further assist steering on the basis of the main steering system. When the main steering system fails, the steering redundancy system replaces the main steering system for subsequent steering control. Specifically, when the main steering system fails, or the main steering system is normal but the steering angle is insufficient, the automatic driving controller 1 controls the switching of two three-position three-way solenoid valves 4, so that one actuating cylinder 5 is connected to the atmosphere 9 through the air pipe 8, and the other actuating cylinder 5 is connected to the air suspension tank 2 through the air pipe 8. The high-pressure gas in the air suspension tank 2 pushes the actuating cylinder 5, which in turn pushes the corresponding steering knuckle to steer; the steering knuckle drives the other steering knuckle to rotate synchronously through the original structure of the intelligent driving vehicle.

[0047] The steering redundancy system of the present application can also work when the main steering system is normal, that is, in some special scenarios, when the steering angle of the main steering system is insufficient, the steering redundancy system can further steer on the basis of the main steering system and expand the steering angle, so that the steering angle of the intelligent driving vehicle is greater than that of a conventional vehicle, and the steering range is larger and more flexible. When the main steering system fails, the steering redundancy system replaces the main steering system to perform subsequent steering control, which can enable both normal low-speed driving and pull-over parking. Compared with the existing steering failure response system, the steering redundancy system of the present application has wider functions and more applicable scenarios. At the same time, the steering knuckle is pushed by two actuating cylinders 5 to steer the wheels. Compared with the existing steering failure response system, which inflates and deflates the left and right front wheels, the control efficiency is high and the response is fast.

[0048] In one embodiment, the three-position three-way solenoid valve 4 includes a first working position 41, a second working position 42 and a third working position 43. When the three-position three-way solenoid valve 4 is in the first working position 41, the three-position three-way solenoid valve 4 connects the actuating cylinder 5 with the air suspension gas tank 2, and the air suspension gas tank 2 inflates the actuating cylinder 5 and pushes the movable end of the actuating cylinder 5 to move. When the three-position three-way solenoid valve 4 is in the second working position 42, the three-position three-way solenoid valve 4 cuts off the actuating cylinder 5 from the air suspension gas tank 2, and the three-position three-way solenoid valve 4 closes the ports of the air pipe 8 on both sides, so that the air chamber of the actuating cylinder 5 is in a closed state, hindering the movement of the piston rod.

[0049] When the three-position three-way solenoid valve 4 is in the third working position 43, the three-position three-way solenoid valve 4 closes the air pipe 8 port on the side of the air suspension air tank 2, and connects the air pipe on the side of the actuating cylinder 5 to the atmosphere 9. At this time, the air chamber of the actuating cylinder 5 corresponding to the three-position three-way solenoid valve 4 has no pressure and is in a free state.

[0050] When the main steering system is running and the steering redundancy system is not involved in the work, the two three-position three-way solenoid valves 4 are both in the third working position 43, the air chambers of the two actuating cylinders 5 are both connected to the atmosphere 9, and the pistons of the actuating cylinders 5 are in a free moving state. When the main steering system fails, or the main steering system is normal but the steering angle is insufficient, one three-position three-way solenoid valve 4 is in the first working position 41, and the other three-position three-way solenoid valve 4 is in the third working position 43 to achieve left or right steering. When the steering angle reaches the target value, the two three-position three-way solenoid valves 4 are both in the working position 42 to provide resistance to prevent the steering angle from changing due to external interference.

[0051] The steering redundancy system of the present application is cleverly designed with two three-position three-way solenoid valves 4, and is controlled by an automatic driving controller 1. The combination of the three-position three-way solenoid valve 4 and the actuating cylinder 5 can realize left turn of the wheel, right turn of the wheel and keep the direction of the wheel unchanged, and can basically replace the main steering system. It is comprehensive in function, can assist in steering on the basis of the main steering system, and can take over the steering responsibility for normal driving at low speed when the main steering system fails, and can further respond quickly to pull-over parking.

[0052] In one embodiment, the intelligent driving vehicle further comprises a frame crossbeam assembly 3, which comprises a frame crossbeam body and two steering knuckles respectively hinged at both ends of the frame crossbeam body, and the steering knuckles are used to rotatably mount the wheels. The two steering knuckles are connected by a steering tie rod, and when one steering knuckle is pushed by the actuating cylinder to turn, the other steering knuckle is synchronously turned under the action of the steering tie rod.

[0053] Two actuating cylinders 5 are installed on the frame crossbeam body, and the movable end of the actuating cylinder 5 is fixed to the steering knuckle, and the movable end of the actuating cylinder 5 can push the steering knuckle to turn. The left and right front wheels are rotatably mounted on the steering knuckle, and the wheels rotate around the axis of the steering knuckle. When a three-position three-way solenoid valve 4 is in the first working position 41 and the other three-position three-way solenoid valve 4 is in the third working position 43, the movable end of the actuating cylinder 5 corresponding to the first working position 41 pushes one steering knuckle to turn, and drives the other steering knuckle to turn synchronously through the steering tie rod.

[0054] Furthermore, the actuating cylinder 5 comprises a cylinder body, a piston head 52 and a piston rod 51, the side wall of the cylinder body is fixed to the frame crossbeam body through the rod body and the ball joint 6, and the piston head 52 of the actuating cylinder 5 and the cylinder body form an air chamber, which is connected to the three-position three-way solenoid valve 4 through the air pipe 8. The extended end of the piston rod 51 is connected to the steering knuckle through the ball joint 6 and the connecting rod 7, specifically, the connecting rod 7 is obliquely fixed to the steering knuckle, and the end of the connecting rod 7 is hinged and fixed to the extended end of the piston rod 51 through the ball joint.

[0055] When the three-position three-way solenoid valve 4 is in the first working position 41, the high-pressure gas in the air suspension air tank 2 pushes the piston head 52 and then pushes the piston rod 51 to drive the steering knuckle to turn; under the premise that the main steering system fails, when the three-position three-way solenoid valve 4 is in the second working position 42, the air chamber of the actuating cylinder 5 corresponding to the three-position three-way solenoid valve 4 is in a closed state, preventing the piston rod from moving, and the steering knuckle remains stationary; when the three-position three-way solenoid valve 4 is in the third working position 43, the air chamber of the actuating cylinder 5 corresponding to the three-position three-way solenoid valve 4 is connected to the atmosphere 9, and if the steering knuckle is in the forward direction (the rotation angle is zero), it remains stationary. If it is not in the forward direction, it will automatically return to the center under the action of the steering return force of the intelligent driving vehicle, that is, the pistons and piston rods in the two actuating cylinders 5 return to their initial positions.

[0056] In the steering redundancy system of the present application, the actuating cylinder 5 is connected to the steering knuckle through the ball joint 6 and the connecting rod 7 to push the steering knuckle to steer; at the same time, the three-position three-way solenoid valve 4 can realize steering, keeping still and returning to the center, which is basically consistent with the functions of the main steering system; compared with the existing steering fault response system that does not have the return capability, the steering redundancy system of the present application has more comprehensive functions, which lays the foundation for the steering redundancy system to meet normal low-speed driving when the main steering system fails.

[0057] The present application also discloses a control method based on the above-mentioned steering redundancy system, wherein two three-position three-way solenoid valves 4 are electrically connected to the automatic driving controller 1, and the control method comprises the following steps:

[0058] When the main steering system is normal but the steering angle is insufficient, the power steering process is executed; when the main steering system fails, the speed reduction process or the pull-over process is executed;

[0059] The power steering process, the deceleration process and the pull-over process contain the same steering procedure, which includes the following steps:

[0060] The automatic driving controller 1 controls the switching of two three-position three-way solenoid valves 4, so that one actuating cylinder 5 is connected to the atmosphere 9 through the air pipe 8, and the other actuating cylinder 5 is connected to the air suspension air tank 2 through the air pipe 8;

[0061] The corresponding steering knuckle of the actuating cylinder 5 connected to the atmosphere 9 is in a free state, and the actuating cylinder 5 does not generate thrust on it. The air suspension air tank 2 inflates the corresponding actuating cylinder 5, pushes the extended end of the actuating cylinder 5 to drive the corresponding steering knuckle to rotate, and then drives the other steering knuckle (i.e., the steering knuckle in the free state) to rotate synchronously. Specifically, the rotation of one steering knuckle drives the other steering knuckle to rotate synchronously through the steering tie rod.

[0062] The control method of the steering redundancy system of the present application is that when the main steering system is normal but the steering angle is insufficient, the steering redundancy system can further assist the steering on the basis of the main steering system. When the main steering system fails, the steering redundancy system replaces the main steering system and performs subsequent steering control.

[0063] In one embodiment, when the main steering system controls the steering knuckle to reach the limit steering angle but still does not reach the target steering angle, the power steering process is executed to further increase the steering angle of the steering knuckle to the target steering angle. Specifically, the steering redundancy system is based on the main steering system, and the automatic driving controller 1 controls the three-position three-way solenoid valve 4 to connect the actuating cylinder 5 and the air suspension air tank 2, and the power steering wheel is further turned on the original basis.

[0064] Furthermore, the speed reduction driving process includes:

[0065] The steering redundancy system replaces the main steering system to control steering, and the intelligent driving vehicle's braking system reduces the vehicle speed to the first set speed. The intelligent driving vehicle drives at a low speed within the first set speed range. When turning left or right, the steering program is executed and the steering redundancy system is used to turn normally. The reason for driving at a low speed is that the response sensitivity of the steering redundancy system is lower than that of the main steering system, but it can effectively control the steering of the vehicle within the low speed range.

[0066] The process of pull-over parking includes:

[0067] The redundant steering system replaces the main steering system to control the steering, and the braking system of the intelligent driving vehicle reduces the vehicle speed to a second set speed, and pulls over to the side of the road by repeatedly executing the steering procedure; the second set speed is less than the first set speed. Specifically, the steering procedure is executed at least twice so that the vehicle body is flush with the roadside.

[0068] The control method of the steering redundancy system of the present application can execute the deceleration driving process and the pull-over parking process after the main steering system fails, and has comprehensive functions. The key to the deceleration driving process is that the sensitivity of the steering redundancy system of the present application is much higher than the reaction sensitivity of the inflation and deflation of the left and right front wheels of the existing steering failure response system, which is also the main reason why the steering redundancy system of the present application can travel at a low speed within the first set vehicle speed range.

[0069] The reason why the pull-over process responds quickly is that pull-over parking only requires the vehicle speed to be reduced to the second set speed, and then emergency pull-over parking is performed; the deceleration value for pull-over parking is greater than that of the existing steering failure response system. For example, the steering redundancy system of this application can reduce the speed to 15km / h for pull-over parking; while the existing steering failure response system can only reduce the speed to 8km / h before pulling over. The steering redundancy system of this application can complete the deceleration in a shorter time, and the subsequent steering using the actuator cylinder 5 is more efficient, the steering redundancy system has a faster overall response, and can achieve pull-over parking faster.

[0070] In one embodiment, the three-position three-way solenoid valve 4 includes a first working position 41, a second working position 42 and a third working position 43. When the three-position three-way solenoid valve 4 is in the first working position 41, the three-position three-way solenoid valve 4 connects the actuating cylinder 5 with the air suspension gas tank 2, and the air suspension gas tank 2 inflates the actuating cylinder 5 and pushes the movable end of the actuating cylinder 5 to move. When the three-position three-way solenoid valve 4 is in the second working position 42, the three-position three-way solenoid valve 4 cuts off the actuating cylinder 5 from the air suspension gas tank 2, and the three-position three-way solenoid valve 4 closes the ports of the air pipe 8 on both sides, so that the air chamber of the actuating cylinder 5 is in a closed state, hindering the movement of the piston rod. When the three-position three-way solenoid valve 4 is in the third working position 43, the three-position three-way solenoid valve 4 closes the port of the air pipe 8 on one side of the air suspension gas tank 2, and connects the air pipe on one side of the actuating cylinder 5 to the atmosphere 9. At this time, the air chamber of the actuating cylinder 5 corresponding to the three-position three-way solenoid valve 4 is pressure-free and in a free state.

[0071] When the main steering system is running and the steering redundancy system is not involved in the work, the two three-position three-way solenoid valves 4 are both in the third working position 43, the air chambers of the two actuating cylinders 5 are connected to the atmosphere 9, and the pistons of the actuating cylinders 5 are in a free moving state.

[0072] The steering procedure consists of the following steps:

[0073] The automatic driving controller 1 controls a three-position three-way solenoid valve 4 to be in the third working position 43, and the corresponding actuating cylinder 5 is connected to the atmosphere 9 through the air pipe 8; controls another three-position three-way solenoid valve 4 to be in the first working position 41, and the corresponding actuating cylinder 5 is connected to the air suspension air tank 2 through the air pipe 8 to achieve left and right steering.

[0074] Furthermore, reducing the vehicle speed to the first set speed in the deceleration process and reducing the vehicle speed to the second set speed in the pull-over process both include:

[0075] The intelligent driving vehicle continues to travel along the predetermined trajectory. If the vehicle deviates from the trajectory, the automatic driving controller 1 corrects the vehicle's motion trajectory to the predetermined trajectory by switching the working positions of the two three-position three-way solenoid valves 4 until the vehicle speed is reduced to the first set speed or the second set speed.

[0076] Specifically, the deceleration process reduces the vehicle speed to the first set vehicle speed, and the pull-over process reduces the vehicle speed to the second set vehicle speed, both of which include:

[0077] The intelligent driving vehicle continues to drive along the predetermined trajectory. If the trajectory deviates, the steering redundancy system corrects it by switching the working positions of the two three-position three-way solenoid valves 4 until the vehicle speed is reduced to the first set speed or the second set speed. Specifically, the intelligent driving vehicle drives at a low speed within the first set speed range, and the intelligent driving vehicle starts to turn and pull over at the second set speed.

[0078] Specifically, the process of continuing to drive along the predetermined trajectory includes:

[0079] The steering redundancy system first ensures that the front wheel rotation angle remains unchanged, and the intelligent driving controller 1 controls the two three-position three-way solenoid valves 4 to switch to the second working position 42. The air chambers of the two actuating cylinders 5 are in a closed state, hindering the movement of the piston rod, which has the effect of locking the steering angle of the front wheel.

[0080] If the trajectory deviation occurs, assuming that the vehicle deviates from the driving trajectory to the left (i.e., the steering must turn right to return to the planned trajectory), the intelligent driving controller 1 controls the right three-position three-way solenoid valve 4 to be adjusted from the second working position 42 to the first working position 41, and the right actuating cylinder 5 pushes the right front wheel to turn right; at the same time, the intelligent driving controller 1 controls the left three-position three-way solenoid valve 4 to be adjusted from the second working position 42 to the first working position 41, so that the piston rod of the left actuating cylinder 5 is in a free state and does not hinder the rotation of the left front wheel. When the right front wheel turns to the right, the left front wheel is driven to turn to the right synchronously through the steering tie rod. When the front wheel turns to the target angle, the intelligent driving controller 1 controls the two three-position three-way solenoid valves 4 to be adjusted to the second working position 42 and continue driving.

[0081] Furthermore, the pull-over parking process includes:

[0082] The automatic driving controller 1 determines whether the two front wheels are in the forward direction (steering angle is zero). If so, proceed to the next step; if not, execute the steering program to control the two front wheels to return to the forward direction; specifically, the two wheels are returned to the forward direction by switching and adjusting two three-position three-way solenoid valves 4.

[0083] The perception system of the intelligent driving vehicle determines the parking direction, executes the steering program, and controls the vehicle to turn in the parking direction; the vehicle continues to drive, and the perception system senses that the front of the vehicle is offset to the parking direction to a set lateral distance. Specifically, the steering program in this step includes the automatic driving controller 1 controlling a three-position three-way solenoid valve 4 close to the parking direction to be adjusted to the first working position 41, and a three-position three-way solenoid valve 4 away from the parking direction to be adjusted to the third working position 43, and the vehicle turns in the parking direction.

[0084] The steering program is executed and the vehicle is controlled to turn in the opposite direction of the parking direction; the vehicle continues to drive, and the perception system perceives that the vehicle body is parallel to the road edge, and the vehicle stops. Specifically, in this step, the steering program is executed, and the automatic driving controller 1 controls a three-position three-way solenoid valve 4 close to the parking direction to be adjusted to the third working position 43, and a three-position three-way solenoid valve 4 away from the parking direction is adjusted to the first working position 41, and the vehicle turns in the opposite direction of the parking direction.

[0085] In the steering redundancy system of the present application, the automatic driving controller 1 controls two three-position three-way solenoid valves 4, and the air suspension air tank 2 drives two actuating cylinders 5 and further drives the two steering knuckles to steer. Compared with the existing steering failure response system that inflates and deflates the left and right wheels, it has a faster response and can complete pull-over parking within a shorter forward distance.

[0086] Furthermore, after the vehicle stops, the automatic driving controller 1 controls the working positions of the two three-position three-way solenoid valves 4 to return the two wheels to the center position, facilitating subsequent operations.

[0087] In one embodiment, the intelligent driving vehicle further comprises a frame crossbeam assembly 3, which comprises a frame crossbeam body and two steering knuckles respectively hinged at both ends of the frame crossbeam body, and the steering knuckles are used to rotatably mount the wheels. The two steering knuckles are connected by a steering tie rod, and when one steering knuckle is pushed by the actuating cylinder to turn, the other steering knuckle is synchronously turned under the action of the steering tie rod.

[0088] Two actuating cylinders 5 are installed on the frame crossbeam body, and the movable end of the actuating cylinder 5 is fixed to the steering knuckle, and the movable end of the actuating cylinder 5 can push the steering knuckle to turn. The left and right front wheels are rotatably mounted on the steering knuckle, and the wheels rotate around the axis of the steering knuckle. When a three-position three-way solenoid valve 4 is in the first working position 41 and the other three-position three-way solenoid valve 4 is in the third working position 43, the movable end of the actuating cylinder 5 corresponding to the first working position 41 pushes one steering knuckle to turn, and drives the other steering knuckle to turn synchronously through the steering tie rod.

[0089] Furthermore, the actuating cylinder 5 comprises a cylinder body, a piston head 52 and a piston rod 51, the side wall of the cylinder body is fixed to the frame crossbeam body through the rod body and the ball joint 6, and the piston head 52 of the actuating cylinder 5 and the cylinder body form an air chamber, which is connected to the three-position three-way solenoid valve 4 through the air pipe 8. The extended end of the piston rod 51 is connected to the steering knuckle through the ball joint 6 and the connecting rod 7, specifically, the connecting rod 7 is obliquely fixed to the steering knuckle, and the end of the connecting rod 7 is hinged and fixed to the extended end of the piston rod 51 through the ball joint.

[0090] When the three-position three-way solenoid valve 4 is in the first working position 41, the high-pressure gas in the air suspension air tank 2 pushes the piston head 52 and then pushes the piston rod 51 to drive the steering knuckle to turn; under the premise that the main steering system fails, when the three-position three-way solenoid valve 4 is in the second working position 42, the air chamber of the actuating cylinder 5 corresponding to the three-position three-way solenoid valve 4 is in a closed state, preventing the piston rod from moving, and the steering knuckle remains stationary; when the three-position three-way solenoid valve 4 is in the third working position 43, the air chamber of the actuating cylinder 5 corresponding to the three-position three-way solenoid valve 4 is connected to the atmosphere 9, and if the steering knuckle is in the forward direction (the rotation angle is zero), it remains stationary. If it is not in the forward direction, it will automatically return to the center under the action of the steering return force of the intelligent driving vehicle, that is, the pistons and piston rods in the two actuating cylinders 5 return to their initial positions.

[0091] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0092] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0093] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A steering redundancy system for an intelligent driving vehicle, characterized in that: The steering redundancy system comprises an air suspension gas tank (2), two three-position three-way solenoid valves (4) and two actuating cylinders (5); the side walls of the two actuating cylinders (5) are fixed to the frame crossbeam body, and the movable ends of the two actuating cylinders (5) are respectively connected to two steering knuckles for mounting wheels; the air suspension gas tank (2) is divided into two branches, and each branch is sequentially connected to the three-position three-way solenoid valve (4) and the actuating cylinder (5) through an air pipe (8); The steering redundancy system is used to switch the working positions of two three-position three-way solenoid valves (4), change the connection or disconnection state between the air suspension air tank (2) and the two actuating cylinders (5), and promote the steering of the left and right steering knuckles; The three-position three-way solenoid valve (4) comprises a first working position (41) for connecting the actuating cylinder (5) and the air suspension gas tank (2), a second working position (42) for disconnecting the actuating cylinder (5) and the air suspension gas tank (2), and a third working position (43) for closing the port of the air pipe (8) on the air suspension gas tank (2) side and connecting the air pipe (8) on the actuating cylinder (5) side to the atmosphere (9); When a main steering system fails, or the main steering system is normal but its steering angle is insufficient, one three-position three-way solenoid valve (4) is in the third working position (43); the other three-position three-way solenoid valve (4) is in the first working position (41), and its corresponding actuating cylinder (5) pushes the corresponding steering knuckle to steer.

2. The intelligent driving vehicle steering redundancy system according to claim 1, characterized in that: The intelligent driving vehicle further comprises a frame crossbeam assembly (3), the frame crossbeam assembly (3) comprising a frame crossbeam body and two steering knuckles respectively hinged to the two ends of the frame crossbeam body; the two steering knuckles are connected by a steering tie rod; the side walls of the two actuating cylinders (5) are mounted on the frame crossbeam body, and the movable ends of the actuating cylinders (5) are fixed to the steering knuckles; The actuating cylinder (5) comprises a cylinder body, a piston head (52) and a piston rod (51); the side wall of the cylinder body is fixed to the frame crossbeam body through the rod body and the ball joint (6); the piston head (52) of the actuating cylinder (5) and the cylinder body form an air chamber, and the air chamber is connected to the three-position three-way solenoid valve (4) through the air pipe (8); the protruding end of the piston rod (51) is connected to the steering knuckle through the ball joint (6) and the connecting rod (7).

3. A control method based on the steering redundancy system according to claim 1, characterized in that: Two three-position three-way solenoid valves (4) are electrically connected to the automatic driving controller (1), and the control method comprises the following steps: When the main steering system is normal but the steering angle is insufficient, the power steering process is executed; when the main steering system fails, the speed reduction process or the pull-over process is executed; The power steering process, the deceleration driving process and the pull-over parking process include the same steering procedure, and the steering procedure includes the following steps: The automatic driving controller (1) controls the switching of two three-position three-way solenoid valves (4), so that one actuating cylinder (5) is connected to the atmosphere (9) through the air pipe (8), and the other actuating cylinder (5) is connected to the air suspension air tank (2) through the air pipe (8); The air suspension gas storage tank (2) inflates the corresponding actuating cylinder (5), pushes the movable end of the actuating cylinder (5) to drive the corresponding steering knuckle to rotate, and then drives another steering knuckle to rotate synchronously.

4. The control method of the steering redundant system according to claim 3, characterized in that: When the main steering system controls the steering knuckle to reach the limit steering angle but still does not reach the target steering angle, the power steering process is executed to further increase the steering angle of the steering knuckle to the target steering angle.

5. The control method of the steering redundant system as claimed in claim 3, characterized in that: The deceleration driving process includes: The steering redundancy system replaces the main steering system, and the braking system of the intelligent driving vehicle reduces the vehicle speed to the first set speed. The intelligent driving vehicle travels at a low speed within the first set speed range; when turning left or right, the steering program is executed; The pull-over parking process includes: The steering redundancy system replaces the main steering system, and the braking system of the intelligent driving vehicle reduces the vehicle speed to a second set speed, and pulls over to the side of the road by repeatedly executing the steering program; the second set speed is less than the first set speed.

6. The control method of the steering redundancy system according to claim 5, characterized in that: The steering procedure comprises the following steps: The automatic driving controller (1) controls a three-position three-way solenoid valve (4) to be in a third working position (43), and the corresponding actuating cylinder (5) is connected to the atmosphere (9) through an air pipe (8); and controls another three-position three-way solenoid valve (4) to be in a first working position (41), and the corresponding actuating cylinder (5) is connected to an air suspension air storage tank (2) through an air pipe (8).

7. The control method of the steering redundancy system according to claim 6, characterized in that: The process of reducing the vehicle speed to a first set vehicle speed in the deceleration process and the process of reducing the vehicle speed to a second set vehicle speed in the pull-over process both include: The intelligent driving vehicle continues to travel along a predetermined trajectory. If the vehicle deviates from the trajectory, the automatic driving controller (1) corrects the vehicle's motion trajectory to the predetermined trajectory by switching the working positions of two three-position three-way solenoid valves (4) until the vehicle speed is reduced to a first set speed or a second set speed.

8. The control method of the steering redundant system as claimed in claim 6, characterized in that: The pull-over parking process includes: The automatic driving controller 1 determines whether the two front wheels are in the forward direction. If so, it proceeds to the next step; if not, it executes the steering program to control the two front wheels to return to the forward direction; The perception system of the intelligent driving vehicle determines the parking direction, executes the steering program and controls the vehicle to turn in the parking direction; the vehicle continues to drive, and the perception system senses that the front of the vehicle deviates to the parking direction to the set lateral distance; The steering program is executed and the vehicle is controlled to turn in the opposite direction of the parking direction; the vehicle continues to move, and the perception system senses that the vehicle body is parallel to the road edge and the vehicle stops.

9. The control method of the steering redundant system according to claim 3, characterized in that: The intelligent driving vehicle further comprises a frame crossbeam assembly (3), the frame crossbeam assembly (3) comprising a frame crossbeam body and two steering knuckles respectively hinged to the two ends of the frame crossbeam body, the two steering knuckles being connected via a steering tie rod; two actuating cylinders (5) are mounted on the frame crossbeam body, and the movable ends of the actuating cylinders (5) are fixed to the steering knuckles; The actuating cylinder (5) comprises a cylinder body, a piston head (52) and a piston rod (51); the side wall of the cylinder body is fixed to the frame crossbeam body through the rod body and the ball joint (6); the piston head (52) of the actuating cylinder (5) and the cylinder body form an air chamber, and the air chamber is connected to the three-position three-way solenoid valve (4) through the air pipe (8); the protruding end of the piston rod (51) is connected to the steering knuckle through the ball joint (6) and the connecting rod (7).

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