Heavy-load AGV all-wheel steering system

Abstract

The utility model relates to a heavy-load AGV all-wheel steering system which comprises a front wheel steering device and a rear wheel steering device, the front wheel steering device and the rear wheel steering device each comprise a steering transmission mechanism and a steering controller, the steering transmission mechanisms are connected with an axle and a frame respectively, and the steering transmission mechanisms are in control connection with an ECU controller through the steering controllers; the front wheel steering device and the rear wheel steering device are adopted and are independent, and when one steering device breaks down, normal work of the other steering device is not affected; the steering controller receives a steering angle instruction of the ECU and meanwhile receives the actual wheel steering angle fed back by the steering angle sensor, closed-loop control over the electro-hydraulic proportional valve set is achieved, and the steering angle control precision is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle steering, in particular to a heavy-load AGV all-wheel steering system. Background Art

[0002] AGV is an automatic guided vehicle or unmanned transport vehicle, which is equipped with electromagnetic or optical automatic guidance devices, can travel along the specified guidance path, and has safety protection and various transfer functions. The AGV with automatic transfer device can automatically complete the whole process of picking up and placing goods and horizontal operation under the command of the control system.

[0003] There are two methods for the existing AGV steering system. The first method uses a motor to control a hydraulic pump to achieve steering control. Since the change in the flow rate and the establishment of pressure in the hydraulic system take a certain amount of time, there are problems such as a large steering response delay and a slow response speed. The second method uses a motor to control a hydraulic pump to achieve steering control. Since the change in the flow rate and the establishment of pressure in the hydraulic system take a certain amount of time, there are problems such as a large steering response delay and a slow response speed. Summary of the invention

[0004] The utility model proposes a heavy-load AGV all-wheel steering system, which adopts a front-wheel steering device and a rear-wheel steering device, and the two devices are independent. When a certain steering device fails, it will not affect the normal operation of the other steering device; a steering controller receives a steering angle command from an ECU and simultaneously receives the actual steering angle of the wheel fed back by a steering angle sensor, thereby realizing closed-loop control of an electro-hydraulic proportional valve group and improving the steering angle control accuracy.

[0005] In order to solve the problems in the above background technology, the present invention is implemented through the following technical solutions:

[0006] A heavy-duty AGV all-wheel steering system comprises a front-wheel steering device and a rear-wheel steering device, wherein the front-wheel steering device and the rear-wheel steering device both comprise a steering transmission mechanism and a steering controller, wherein the steering transmission mechanism is respectively connected to the vehicle axle and the vehicle frame, and the steering transmission mechanism is controlled and connected to an ECU controller via the steering controller.

[0007] Furthermore, the steering transmission mechanism includes a steering mechanism and a transmission mechanism; the steering mechanism includes a hydraulic booster cylinder, an oil cooler, an electro-hydraulic proportional valve group, a steering oil tank, and an electric hydraulic pump; the power output end of the hydraulic booster cylinder is connected to the axle through the moving end of the transmission mechanism, and the fixed end of the hydraulic booster cylinder is connected to the frame; the oil outlet of the steering oil tank is connected to the oil inlet of the electric hydraulic pump, the oil outlet of the electric hydraulic pump is connected to the oil inlet of the electro-hydraulic proportional valve group, the oil outlet of the electro-hydraulic proportional valve group is connected to the oil inlet of the oil cooler, the oil outlet of the oil cooler is connected to the oil inlet of the steering oil tank, the electro-hydraulic proportional valve group is controlled and connected to the ECU controller through the steering controller, and the fixed end of the transmission mechanism is connected to the frame.

[0008] Furthermore, the axle is also provided with a rotation angle sensor, and the rotation angle sensor is connected to the ECU controller.

[0009] Furthermore, a liquid level alarm and an oil temperature sensor are provided in the steering oil tank, and both the liquid level alarm and the oil temperature sensor are connected to the steering controller.

[0010] Compared with the prior art, the utility model has the following beneficial technical effects:

[0011] The front-wheel steering device and the rear-wheel steering device are adopted, and the two devices are independent. When a single steering device fails, it will not affect the normal operation of the other steering device. The steering controller receives the steering angle command from the ECU and the actual steering angle of the wheel fed back by the steering angle sensor at the same time, realizing closed-loop control of the electro-hydraulic proportional valve group and improving the steering angle control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the utility model.

[0013] Reference numerals

[0014] 1. Steering controller; 2. Axle; 3. Frame; 4. Hydraulic booster cylinder; 41. Hydraulic booster cylinder A; 42. Hydraulic booster cylinder B; 43. Hydraulic booster cylinder C; 44. Hydraulic booster cylinder D; 5. Oil cooler; 6. Electro-hydraulic proportional valve group; 7. Steering oil tank; 8. Electric hydraulic pump; 9. Transmission mechanism; 10. Angle sensor. DETAILED DESCRIPTION

[0015] like Figure 1 As shown, a heavy-duty AGV all-wheel steering system includes a front-wheel steering device and a rear-wheel steering device. The front-wheel steering device and the rear-wheel steering device both include a steering transmission mechanism and a steering controller 1. The steering transmission mechanism is connected to the axle 2 and the frame 3 respectively. The steering transmission mechanism is controlled and connected to the ECU controller through the steering controller 1.

[0016] The steering transmission mechanism includes a steering mechanism and a transmission mechanism 9; the steering mechanism includes a hydraulic booster cylinder 4, an oil cooler 5, an electro-hydraulic proportional valve group 6, a steering oil tank 7, and an electric hydraulic pump 8; the power output end of the hydraulic booster cylinder 4 is connected to the axle 2 through the moving end of the transmission mechanism 9, and the fixed end of the hydraulic booster cylinder 4 is connected to the frame 3; the oil outlet of the steering oil tank 7 is connected to the oil inlet of the electric hydraulic pump 8, the oil outlet of the electric hydraulic pump 8 is connected to the oil inlet of the electro-hydraulic proportional valve group 6, the oil outlet of the electro-hydraulic proportional valve group 6 is connected to the oil inlet of the oil cooler 5, the oil outlet of the oil cooler 5 is connected to the oil inlet of the steering oil tank 7, the electro-hydraulic proportional valve group 6 is connected to the ECU controller through the steering controller 1, and the fixed end of the transmission mechanism 9 is connected to the frame 3.

[0017] The electro-hydraulic proportional valve group 6 includes a proportional servo valve, a unloading valve, a one-way valve, and an electromagnetic overflow valve (not shown in the figure); the proportional servo valve is used to control the direction, and drives the valve core to adjust the output flow according to the signal, thereby controlling the displacement of the hydraulic booster cylinder 4; the unloading valve is a safety valve, which is used to protect the pressure shock caused by sudden load changes in the cavity of the hydraulic booster cylinder 4; the electromagnetic overflow valve is used to unload the hydraulic booster cylinder 4 to ensure that the cylinder cavity is not subjected to force in the straight-line state or fault state; the one-way valve is a check valve, which is used for the one-way flow of oil in the hydraulic booster cylinder 4.

[0018] When the vehicle is driving straight normally: the proportional servo valve is in the middle position, the electromagnetic relief valve is in the open state, and the hydraulic oil output by the electric hydraulic pump 8 flows back to the steering oil tank 7 through the electromagnetic relief valve;

[0019] When the vehicle turns left normally: the electromagnetic overflow valve receives the electrical signal from the steering controller 1, and the electromagnetic overflow valve is closed; the proportional valve servo valve receives the electrical signal from the steering controller 1, and the proportional valve servo valve is controlled to the right position, and the rod chamber high pressure of the hydraulic booster cylinder B42 and the hydraulic booster cylinder D44, and the rodless chamber high pressure of the hydraulic booster cylinder A41 and the hydraulic booster cylinder C43 drive the wheels to realize the steering action;

[0020] When the vehicle turns right normally: the solenoid overflow valve receives the electrical signal from the steering controller 1, and the solenoid overflow valve is closed; the proportional valve servo valve receives the electrical signal from the steering controller 1, and the proportional valve servo valve is controlled to the left position, and the rodless chamber high pressure of the hydraulic booster cylinder B42 and the hydraulic booster cylinder D44, and the rod chamber high pressure of the hydraulic booster cylinder A41 and the hydraulic booster cylinder C43 drive the wheels to realize the steering action.

[0021] The axle 2 is also provided with a rotation angle sensor 10 , and the rotation angle sensor 10 is connected to the ECU controller.

[0022] A liquid level alarm and an oil temperature sensor are arranged in the steering oil tank 7 , and both the liquid level alarm and the oil temperature sensor are connected to the steering controller 1 .

[0023] A liquid level alarm is provided. When the liquid level in the steering oil tank 7 is lower than the alarm height, the liquid level alarm switch is closed, and the alarm signal is fed back to the steering controller 1. An oil temperature sensor is provided in the steering oil tank 7 to feed back the hydraulic oil temperature in the steering oil tank 7 to the steering controller 1 in real time.

[0024] An active heat dissipation control module is provided in the oil cooler 5 to control the hydraulic system oil temperature to maintain the optimal working temperature. When the hydraulic system oil temperature exceeds the set value, the fan works and the active heat dissipation is turned on. When the hydraulic system oil temperature is lower than the design value, the fan is turned off and the active heat dissipation is turned off.

[0025] At the same time, it also has the following four operating modes:

[0026] 1. Straight driving mode: the front wheel steering device and the rear wheel steering device are both in the neutral lock state;

[0027] 2. All-wheel steering mode: The front-wheel steering device and the rear-wheel steering device receive the turning angle instructions from the ECU controller respectively, and the turning angle directions are opposite;

[0028] 3. Front and rear wheel steering mode: The front wheel steering device and the rear wheel steering device receive the turning angle command from the ECU controller respectively, and the corresponding rear wheel steering device or front wheel steering device is in the neutral lock state;

[0029] 4. Crab mode: The front wheel steering device and the rear wheel steering device receive the turning angle instructions from the ECU controller respectively, and the turning angle directions are the same;

[0030] The above-mentioned neutral position locking is achieved in the following two ways:

[0031] Hydraulic method: The proportional servo valve is in the middle position, closing the oil circuit in the 4th chamber of the hydraulic booster cylinder;

[0032] Control method: When the steering angle value fed back by the steering angle sensor 10 exceeds the set value, the steering controller 1 drives the electro-hydraulic proportional valve group 6 to start and drives the hydraulic booster cylinder 4 back to the neutral position.

Claims

1. A heavy-duty AGV all-wheel steering system, characterized by: The vehicle comprises a front wheel steering device and a rear wheel steering device, each of which comprises a steering transmission mechanism and a steering controller (1), wherein the steering transmission mechanism is connected to a vehicle axle (2) and a vehicle frame (3) respectively, and the steering transmission mechanism is connected to an ECU controller through the steering controller (1); The steering transmission mechanism comprises a steering mechanism and a transmission mechanism (9); the steering mechanism comprises a hydraulic booster cylinder (4), an oil cooler (5), an electro-hydraulic proportional valve group (6), a steering oil tank (7), and an electric hydraulic pump (8); the power output end of the hydraulic booster cylinder (4) is connected to the axle (2) through the moving end of the transmission mechanism (9), and the fixed end of the hydraulic booster cylinder (4) is connected to the frame (3); the oil outlet of the steering oil tank (7) is connected to the oil inlet of the electric hydraulic pump (8), the oil outlet of the electric hydraulic pump (8) is connected to the oil inlet of the electro-hydraulic proportional valve group (6), the oil outlet of the electro-hydraulic proportional valve group (6) is connected to the oil inlet of the oil cooler (5), the oil outlet of the oil cooler (5) is connected to the oil inlet of the steering oil tank (7), the electro-hydraulic proportional valve group (6) is controlled and connected to the ECU controller through the steering controller (1), and the fixed end of the transmission mechanism (9) is connected to the frame (3).

2. The heavy-duty AGV all-wheel steering system according to claim 1, characterized in that: The vehicle axle (2) is also provided with a rotation angle sensor (10), and the rotation angle sensor (10) is connected to the ECU controller.

3. The heavy-duty AGV all-wheel steering system according to claim 1, characterized in that: A liquid level alarm and an oil temperature sensor are arranged in the steering oil tank (7), and both the liquid level alarm and the oil temperature sensor are connected to the steering controller (1).

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