Walking device for crawler chassis, control method and crawler chassis system

Abstract

The invention discloses a walking device for a crawler chassis, a control method and a crawler chassis system. A walking device for a track chassis comprises a linear walking controller, and the linear walking controller is configured to receive an input longitudinal speed instruction; acquiring the rotating speeds of the first and second driving wheels and the transverse deflection angle of the crawler chassis in real time; determining a reference drive signal based on the longitudinal speed command and the first drive wheel speed; generating a drive signal first correction value based on the lateral deflection angle; determining the total transverse dislocation amount of the crawler chassis based on the transverse deflection angle and the rotating speed of the second driving wheel; generating a driving signal second correction value based on the total transverse dislocation amount; taking the larger absolute value in the first correction value of the driving signal and the second correction value of the driving signal as a correction value of the driving signal; generating first and second driving signals based on the reference driving signal and the driving signal correction value; and controlling the opening degree of the first and second electric proportional valves based on the first and second driving signals.

Description

Technical Field

[0001] The present application relates to a traveling device for a crawler chassis and a control method thereof, and also relates to a crawler chassis system including such a traveling device. Background Art

[0002] In the fields of construction machinery vehicles and agricultural machinery vehicles, due to the advantages of high reliability, strong adaptability, simple operation, etc. of crawler chassis, they have been widely used. For certain working conditions of these vehicles, when the vehicle is working on the upper part, it is required that the vehicle can move forward or backward in a straight line at a stable speed, otherwise the quality and efficiency of the upper part operation cannot be satisfied. The traditional way to control the straight-line walking of construction machinery vehicles and agricultural machinery vehicles is to ensure the straight-line walking of the vehicle by the driver controlling the steering of the vehicle. For example, when the vehicle deviates to the left during walking, the driver turns to the right to correct the vehicle attitude. This way of controlling straight-line walking has defects. On the one hand, during the implementation of the operation, the driver needs to observe the situation in real time and perform manual control, resulting in a large labor intensity for the driver, and there are problems such as poor accuracy and stability in manual control; on the other hand, the driver needs to control the upper part operation and the lower part walking at the same time, resulting in low work efficiency. Summary of the Invention

[0003] The purpose of the present application is to provide an improved solution for the straight-line walking control of a crawler chassis.

[0004] To this end, in one aspect of the present application, there is provided a traveling device for a crawler chassis, the crawler chassis including crawlers respectively driven by a first drive wheel and a second drive wheel, the traveling device including a straight-line walking controller and a traveling drive system;

[0005] Wherein, the traveling drive system includes: a hydraulic pump; a first motor for driving the first drive wheel to rotate and a second motor for driving the second drive wheel to rotate; a first closed circuit for transmitting hydraulic oil between the hydraulic pump and the first motor and a second closed circuit for transmitting hydraulic oil between the hydraulic pump and the second motor; a first electro-hydraulic proportional valve for controlling the flow rate of the first closed circuit; and a second electro-hydraulic proportional valve for controlling the flow rate of the second closed circuit;

[0006] The straight-line walking controller is configured to:

[0007] Receive an input longitudinal speed command;

[0008] Obtain the rotational speed of the first drive wheel, the rotational speed of the second drive wheel, and the lateral deflection angle of the crawler chassis in real time;

[0009] Determine a reference drive signal based on the longitudinal speed command and the rotational speed of the first drive wheel;

[0010] Generate a first correction value of the drive signal based on the lateral deflection angle;

[0011] Determine the total lateral misalignment of the crawler chassis based on the lateral deflection angle and the rotational speed of the second drive wheel;

[0012] Generate a second correction value of the drive signal based on the total lateral misalignment;

[0013] Take the larger absolute value of the first correction value of the drive signal and the second correction value of the drive signal as the correction value of the drive signal;

[0014] Generate a first drive signal and a second drive signal based on the reference drive signal and the correction value of the drive signal; and

[0015] Control the opening degree of the first electro-hydraulic proportional valve based on the first drive signal, and control the opening degree of the second electro-hydraulic proportional valve based on the second drive signal.

[0016] In one embodiment, the process of determining the total lateral misalignment of the crawler chassis includes:

[0017] Obtain the lateral misalignment speed of the crawler chassis by multiplying the tangent value of the lateral deflection angle by the traveling speed of the crawler chassis obtained based on the rotational speed of the second drive wheel, and integrate the lateral misalignment speed with respect to time to obtain the total lateral misalignment.

[0018] In one embodiment, the first drive signal is the reference drive signal, and the second drive signal is the reference drive signal plus the correction value of the drive signal.

[0019] In one embodiment, the first drive signal is the reference drive signal * k1 * the correction value of the drive signal, and the second drive signal is the reference drive signal plus k2 * the correction value of the drive signal, where k1 and k2 are correction coefficients.

[0020] In one embodiment, the value ranges of both k1 and k2 are from 0 to 1.

[0021] In one embodiment, k1 + k2 = 1; for example: one of k1 and k2 is 0 and the other is 1, or both k1 and k2 are 0.5.

[0022] In one embodiment, 1 < k1 + k2 < 1.5.

[0023] In one embodiment, k1 < k2.

[0024] In one embodiment, a deflection angle threshold is set in the straight travel controller, and the first correction value of the drive signal is generated only when the lateral deflection angle is greater than the deflection angle threshold.

[0025] In one embodiment, a total offset threshold is set in the straight travel controller, and the second correction value of the drive signal is generated only when the total lateral misalignment is greater than the total offset threshold.

[0026] In one embodiment, the hydraulic pump is a constant pressure variable pump; the traveling drive system further includes a first compensation valve and a second compensation valve. The inlet ports of the first compensation valve and the second compensation valve are respectively connected to the output port of the hydraulic pump. The outlet port of the first compensation valve is connected to the inlet port of the first electro-hydraulic proportional valve, and the first compensation valve is configured to adjust the opening degree based on the system pressure feedback of the first closed loop. The outlet port of the second compensation valve is connected to the inlet port of the second electro-hydraulic proportional valve, and the second compensation valve is configured to adjust the opening degree based on the system pressure feedback of the second closed loop.

[0027] The present application further provides a straight-line traveling control method for a crawler chassis. The crawler chassis includes: crawlers respectively driven by a first drive wheel and a second drive wheel; a hydraulic pump; a first motor for driving the first drive wheel and a second motor for driving the second drive wheel; a first closed loop for transmitting hydraulic oil between the hydraulic pump and the first motor and a second closed loop for transmitting hydraulic oil between the hydraulic pump and the second motor; a first electro-hydraulic proportional valve for controlling the flow rate of the first closed loop; and a second electro-hydraulic proportional valve for controlling the flow rate of the second closed loop.

[0028] The straight-line traveling control method includes:

[0029] Receiving an input longitudinal speed command;

[0030] Real-time obtaining the rotational speed of the first drive wheel, the rotational speed of the second drive wheel, and the lateral deflection angle of the crawler chassis;

[0031] Determining a reference drive signal based on the longitudinal speed command and the rotational speed of the first drive wheel;

[0032] Generating a first correction value of the drive signal based on the lateral deflection angle;

[0033] Determining the total lateral misalignment of the crawler chassis based on the lateral deflection angle and the rotational speed of the second drive wheel;

[0034] Generating a second correction value of the drive signal based on the total lateral misalignment;

[0035] Taking the larger absolute value of the first correction value of the drive signal and the second correction value of the drive signal as the correction value of the drive signal;

[0036] Generating a first drive signal and a second drive signal based on the reference drive signal and the correction value of the drive signal; and

[0037] Controlling the opening degree of the first electro-hydraulic proportional valve based on the first drive signal, and controlling the opening degree of the second electro-hydraulic proportional valve based on the second drive signal.

[0038] The various features in the traveling device of the present application are equally applicable to the straight-line traveling control method of the present application.

[0039] The present application further provides a crawler chassis system, comprising:

[0040] A crawler chassis, the crawler chassis comprising: a first drive wheel and a second drive wheel, and crawlers respectively driven by the first drive wheel and the second drive wheel; and

[0041] A traveling device of the present application, configured to drive the first drive wheel and the second drive wheel to rotate.

[0042] According to the crawler chassis traveling device of the present application, a traveling correction mechanism is provided, which has a fully autonomous straight-line traveling control function and does not require manual intervention operation, greatly reducing the labor intensity of the driver. In addition, the control accuracy of the traveling device is high and the control stability is good. In addition, multiple controllers are adopted in the traveling device to adapt to various road conditions and ensure that the speed and attitude of the vehicle are well controlled simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The foregoing and other aspects of the present application will be more fully understood and appreciated by the following detailed description with reference to the accompanying drawings, in which:

[0044] Figure 1 is a schematic diagram of an exemplary crawler chassis traveling device of the present application;

[0045] Figure 2 is a schematic diagram of a crawler chassis that can adopt the traveling device of the present application;

[0046] Figure 3 is a flowchart of an exemplary traveling device control method of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] The present application generally relates to crawler chassis systems for construction machinery vehicles, agricultural machinery vehicles, etc. These vehicles generally include an upper vehicle and a lower vehicle. The upper vehicle is mounted on the lower vehicle and can perform various operations. The lower vehicle includes a crawler chassis for realizing the traveling of the vehicle.

[0048] The crawler chassis system of the present application includes a crawler chassis and a traveling device. The traveling of the crawler chassis is realized by driving the crawlers through the traveling device. When performing a certain upper vehicle operation on these vehicles, it is required that the lower vehicle can travel in a straight line. The present application provides a traveling device for construction machinery vehicles, agricultural machinery vehicles, etc., which can autonomously realize straight-line traveling without the driver having to manipulate the vehicle steering in real time to correct deviations.

[0049] An exemplary configuration of the traveling device of the present application is shown in Figure 1 The traveling device uses a hydraulic motor as a driving element.

[0050] Refer to Figure 1, the traveling device includes a linear travel controller 1 and a hydraulic travel drive system 2. The linear travel controller 1 can control the travel drive system 2 to achieve linear travel of the vehicle.

[0051] The travel drive system 2 has a single hydraulic pump 12 as a power source. The hydraulic pump 12 is a constant pressure variable pump and can output a constant hydraulic pressure. The hydraulic pump 12 is used to output hydraulic oil to the fixed displacement hydraulic motors 17, 18 to drive the motors 17, 18 (which can be respectively referred to as the first motor and the second motor) to rotate. The motors 17, 18 respectively drive the drive wheels 19, 20 of the crawler chassis (which can be respectively referred to as the first drive wheel and the second drive wheel) to rotate.

[0052] The hydraulic oil quantities output by the hydraulic pump 12 to the motors 17, 18 are respectively controlled by the electro-hydraulic proportional valves 13, 14 (which can be respectively referred to as the first electro-hydraulic proportional valve and the second electro-hydraulic proportional valve).

[0053] The proportional valves 13, 14 have the same structure. Each of the proportional valves 13, 14 respectively has an oil inlet (abbreviated as P port), an oil return port (abbreviated as T port), a first working oil port (abbreviated as A port), a second working oil port (abbreviated as B port), and respectively has three valve positions. In the neutral valve position, the P port, T port, A port, and B port are all cut off. In the first working valve position, the P port is communicated with the A port, and the T port is communicated with the B port. In the second working valve position, the P port is communicated with the B port, and the T port is communicated with the A port.

[0054] The A port and B port of the proportional valve 13 are respectively communicated with the first oil port and the second oil port of the motor 17. The A port and B port of the proportional valve 14 are respectively communicated with the first oil port and the second oil port of the motor 18.

[0055] The valve positions of the proportional valves 13, 14 and the opening degrees in the working valve positions are controlled by the drive currents of the electromagnets applied to the control ends on their respective two sides.

[0056] The output port of the hydraulic pump 12 is branched and connected to the oil inlets of the pressure compensation valves 15, 16 (which can be respectively referred to as the first compensation valve and the second compensation valve). The oil outlet of the pressure compensation valve 15 is connected to the P port of the proportional valve 13, and the oil outlet of the pressure compensation valve 16 is connected to the P port of the proportional valve 14.

[0057] The input port of the hydraulic pump 12 is connected to the fuel tank. And, the T ports of the proportional valves 13, 14 are both connected to the input port of the hydraulic pump 12.

[0058] In this way, a first closed hydraulic circuit is formed between the hydraulic pump 12 and the motor 17, and a second closed hydraulic circuit is also formed between the hydraulic pump 12 and the motor 18.

[0059] The oil pressure at the first-side control end of the pressure compensation valve 15 is taken from the output end of the pressure compensation valve 15, and the oil pressure at the second-side control end is taken from the higher one of the oil pressures on both sides of the motor 17 (the oil pressure at the first oil port and the oil pressure at the second oil port), that is, the load oil pressure, through a shuttle valve.

[0060] The oil pressure at the first-side control end of the pressure compensation valve 16 is taken from the output end of the pressure compensation valve 16, and the oil pressure at the second-side control end is taken from the higher one of the oil pressures on both sides of the motor 18 (the oil pressure at the first oil port and the oil pressure at the second oil port), that is, the load oil pressure, through a shuttle valve.

[0061] When the proportional valves 13 and 14 are both in the neutral valve position, the proportional valves 13 and 14 cut off the hydraulic supply from the hydraulic pump 12 to the motors 17 and 18, and the motors 17 and 18 do not rotate, so the vehicle does not move.

[0062] When the proportional valves 13 and 14 are both in the first working valve position, the hydraulic pump 12 supplies hydraulic oil to the first oil ports of both the motors 17 and 18, driving the motors 17 and 18 to rotate in the forward direction. The motors 17 and 18 drive the corresponding drive wheels 19 and 20 to rotate in the forward direction, and the drive wheels 19 and 20 drive their respective crawlers to move in the first direction (for example, the forward direction). The hydraulic oil in both the motors 17 and 18 returns to the input port of the hydraulic pump 12 through their respective second oil ports.

[0063] When the proportional valves 13 and 14 are both in the second working valve position, the hydraulic pump 12 supplies hydraulic oil to the second oil ports of both the motors 17 and 18, driving the motors 17 and 18 to rotate in the reverse direction. The motors 17 and 18 drive the corresponding drive wheels 19 and 20 to rotate in the reverse direction, and the drive wheels 19 and 20 drive their respective crawlers to move in the second direction (for example, the backward direction). The hydraulic oil in both the motors 17 and 18 returns to the input port of the hydraulic pump 12 through their respective first oil ports.

[0064] When the system pressures in the two closed hydraulic circuits are unbalanced, the pressures are fed back to the second-side control ends of the pressure compensation valves 15 and 16 respectively through their respective shuttle valves, adjusting the flow areas and output pressures of the pressure compensation valves 15 and 16, so that the system pressures in the two closed hydraulic circuits are balanced, maintaining that the motors 17 and 18 transmit approximately balanced driving forces to the drive wheels 19 and 20, which helps the crawler chassis to move straight.

[0065] The output shaft of the motor 17 is connected to the rotating shaft of the drive wheel 19. The output shaft of the motor 17 or the rotating shaft of the drive wheel 19 is equipped with a rotary encoder (which can be called the first rotary encoder or the first rotational speed sensor) 21 for detecting the rotational speeds of the motor 17 and the drive wheel 19.

[0066] The output shaft of the motor 18 is connected to the rotating shaft of the drive wheel 20. The output shaft of the motor 18 or the rotating shaft of the drive wheel 19 is equipped with a rotary encoder (which can be called the second rotary encoder, or the second rotational speed sensor) 22 for detecting the rotational speeds of the motor 18 and the drive wheel 20.

[0067] In addition, the traveling drive system 2 further includes a gyroscope (deflection angle sensor) 23 for detecting the lateral (left and right) deflection angle of the crawler chassis.

[0068] When the driver inputs a vehicle traveling (forward or backward) signal, the driving force is respectively transmitted from the motors 18, 19 to the drive wheels 21, 22, and the drive wheels 21, 22 drive the crawlers to travel, and the two crawlers jointly drive the vehicle to travel. Ideally, if the rotational speeds of the motors 21, 22 are the same, the vehicle can travel in a straight line; if the rotational speeds are different, the vehicle will deflect. However, due to the inconsistent ground conditions in contact with the two crawlers and the mechanical structures on both sides not being completely the same, the same motor rotational speed will result in different crawler speeds, and the vehicle will deflect laterally at the same motor rotational speed. Therefore, to ensure the straight-line travel of the vehicle, it is necessary to collect the vehicle attitude in real time and perform closed-loop adjustment on the opening degree of the proportional valve.

[0069] The straight-line travel controller 1 is configured to receive the travel command signal 3 input by the driver through the command input interface of the vehicle. The command input interface can be a handle, a pedal, a human-machine interaction touch screen, etc. The driver operates the command input interface to generate a travel command signal 3 in the form of current, voltage, or digital, etc. The straight-line travel controller 1 also receives the actual rotational speed signals of the drive wheels 19, 20 from the rotary encoders 21, 22, and the actual lateral deflection angle of the crawler chassis from the gyroscope 23.

[0070] The straight-line travel controller 1 is also connected to the two-side control ends of the proportional valves 13, 14 respectively, for outputting drive signals to the two-side control ends of the proportional valves 13, 14 respectively.

[0071] The straight-line travel controller 1 includes: a command generator 4, a speed controller 5, a multiplier 6, an integrator 7, a lateral offset controller 8, an attitude angle controller 9, a selector 10, and an adder 11.

[0072] The command generator 4 is configured to receive the travel command signal 3 input by the driver. The travel command signal 3 includes the desired longitudinal (front and back) movement direction of the vehicle (forward or backward) and the longitudinal movement speed information. The command generator 4 processes the travel command signal 3 to generate a longitudinal speed command (desired longitudinal travel speed), and sends the longitudinal speed command to the speed controller 5.

[0073] The speed controller 5 receives the longitudinal speed command from the command generator 4 and the actual rotational speed of the drive wheel 19 fed back by the rotary encoder 21. The speed controller 5 compares the longitudinal speed command with the actual rotational speed calculated based on the actual rotational speed of the drive wheel 19, generates a reference drive signal Sa that is positively correlated with the comparison result based on the comparison result, and sends the reference drive signal Sa as the first drive signal to the corresponding control terminal of the proportional valve 13. A drive current is generated in the electromagnet at the corresponding control terminal of the proportional valve 13 to control the valve position and opening of the proportional valve 13. It can be understood that depending on whether the travel command signal 3 indicates that the vehicle is moving forward or backward, the first drive signal is sent to the corresponding one of the two side control terminals of the proportional valve 13.

[0074] The speed controller 5 also sends the reference drive signal Sa to the adder 11.

[0075] The gyroscope 23 detects the lateral deflection angle α of the crawler chassis in real time, and the attitude angle controller 9 receives the actual deflection angle α detected by the gyroscope 23. The deflection angle threshold Δα is stored or received in the attitude angle controller 9. When the actual deflection angle α is greater than the deflection angle threshold Δα, the attitude angle controller 9 generates a first correction value ΔS1 of the drive signal that is positively correlated (e.g., proportional) with the actual deflection angle α based on the actual deflection angle α and the physical dimensions of the crawler chassis, and sends the first correction value ΔS1 of the drive signal to the selector 10. If the actual deflection angle α is less than or equal to the deflection angle threshold Δα, the first correction value ΔS1 of the drive signal is set to zero.

[0076] The relationship between the first correction value ΔS1 and the actual deflection angle α can be simply expressed by a linear expression of the first order. For example, a coefficient c1 can be determined based on the physical dimensions of the crawler chassis, and ΔS1 = c1 * α. Alternatively, a look-up table containing the corresponding values between the first correction value ΔS1 and the actual deflection angle α can be established, and the first correction value ΔS1 corresponding to the actual deflection angle α can be found through this look-up table.

[0077] On the other hand, the multiplier 6 receives the actual deflection angle α detected by the gyroscope 23 and the actual rotational speed signal of the drive wheel 20 fed back by the rotary encoder 22, multiplies the tangent value of the actual deflection angle α by the vehicle (crawler chassis) travel speed signal obtained based on the actual rotational speed signal of the drive wheel 20 to obtain the lateral misalignment speed of the crawler chassis, and sends the lateral misalignment speed to the integrator 7. It can be understood that here the travel speed can be simply obtained by multiplying the rotational speed of the drive wheel 20 by the distance from the center axis of the drive wheel 20 to the ground. Alternatively, the travel speed can be obtained based on the average value of the rotational speeds of the drive wheels 19 and 20 multiplied by the distance from their center axes to the ground.

[0078] In the integrator 7, the lateral misalignment speed is integrated over time to obtain the total lateral misalignment amount Y, and the total lateral misalignment amount Y is sent to the lateral offset controller 8.

[0079] The lateral displacement controller 8 stores or receives the total lateral misalignment threshold ΔY. When the total lateral misalignment Y is greater than the total lateral misalignment threshold ΔY, the lateral displacement controller 8 generates a second correction value ΔS2 of the drive signal that is positively correlated (e.g., proportional) to the total lateral misalignment Y, and sends the second correction value ΔS2 of the drive signal to the selector 10. If the total lateral misalignment Y is less than or equal to the total lateral misalignment threshold ΔY, the total lateral misalignment Y is set to zero.

[0080] The relationship between the second correction value ΔS2 and the total lateral misalignment Y can be simply expressed by a first-order linear expression. For example, a coefficient c2 can be determined based on the physical dimensions of the crawler chassis, ΔS2 = c2 * Y. Alternatively, a look-up table containing the corresponding values between the second correction value ΔS2 and the total lateral misalignment Y can be established, and the second correction value ΔS2 corresponding to the total lateral misalignment Y can be found through this look-up table.

[0081] The values of the first correction value ΔS1 and the second correction value ΔS2 can be positive or negative. When the output value of the rotary encoder 22 is greater than the output value of the rotary encoder 21, the first correction value ΔS1 and the second correction value ΔS2 are negative; when the output value of the rotary encoder 22 is less than the output value of the rotary encoder 21, the first correction value ΔS1 and the second correction value ΔS2 are positive

[0082] In the selector 10, the larger of the absolute values of the first correction value ΔS1 and the second correction value ΔS2 is selected as the drive signal correction value ΔS (which can be positive or negative), and the drive signal correction value ΔS is sent to the adder 11. In the adder 11, the reference drive signal Sa is added to the drive signal correction value ΔS to obtain a corrected drive signal Sb, and the corrected drive signal Sb is sent as the second drive signal to the control end of the proportional valve 14. A drive current is generated in the electromagnet at the control end of the proportional valve 14 to control the valve position and opening of the proportional valve 14. It can be understood that, depending on whether the travel command signal 3 indicates that the vehicle is moving forward or backward, the second drive signal is sent to the corresponding one of the two control ends of the proportional valve 13.

[0083] Through the above control method, the straight-line travel controller 1 sends the first drive signal (reference drive signal Sa) to the control end of the proportional valve 13, and sends the second drive signal (corrected drive signal Sb = Sa + ΔS) to the control end of the proportional valve 14. Thus, by controlling the opening degrees of the proportional valves 13 and 14 with different drive signals, the hydraulic oil flow rate from the hydraulic pump 12 to the motor 18 is corrected, the rotational speed of the drive wheel 20 is corrected, and the direction of the crawler chassis is corrected in real time, so that the crawler chassis maintains a generally constant straight-line forward or backward travel.

[0084] It should be noted that in software, various data mentioned above are usually calculated in the form of normalized dimensionless data during calculations, so there is no need to consider their actual dimensions.

[0085] In the straight-line walking controller 1, the instruction generator 4, speed controller 5, multiplier 6, integrator 7, lateral offset controller 8, attitude angle controller 9, selector 10, and adder 11 are all implemented in the form of software modules, or in the form of software modules plus hardware.

[0086] Furthermore, the first drive signal can be taken as (Sa - k1 * ΔS) and sent to the control end of the proportional valve 13, and the second drive signal can be taken as (Sa + k2 * ΔS) and sent to the control end of the proportional valve 14, which can also correct the direction of the crawler chassis in real time and keep the crawler chassis moving forward or backward in a straight line approximately constantly. k1 and k2 are correction factors, and the preferred value ranges are both from 0 to 1. k1 and k2 can be equal. Or, k1 and k2 can be unequal. Preferably, k1 < k2, which can avoid excessive reciprocating swing of the traveling direction of the crawler belt sprocket.

[0087] Generally, k1 + k2 = 1 can be taken. For example, most simply, one of k1 and k2 is taken as 0 and the other as 1; or both k1 and k2 are 0.5, in which case only the rotational speed of one of the drive wheels needs to be adjusted. Or, 1 < k1 + k2 < 1.5 can be taken, in which case compensation in the reverse direction of the deflection direction of the crawler chassis can be achieved by correcting the rotational speed of the drive wheels, and it is easier to quickly achieve the expected vehicle traveling direction.

[0088] The settings of the deflection angle threshold Δα and the total lateral misalignment threshold ΔY can avoid the straight-line walking controller 1 from frequently correcting the rotational speed of the drive wheels and improve the stability of control. One or both of the deflection angle threshold Δα and the total lateral misalignment threshold ΔY can be adjustable.

[0089] The crawler chassis of the present application can adopt the above-mentioned traveling device and is schematically shown in Figure 2 See Figure 2 , the crawler chassis of the present application includes a pair of crawlers 25. At the longitudinal one end (usually the front end) of the lower frame 26 of the vehicle, a pair of drive wheels 19, 20 are installed (the drive wheel 20 is not shown in Figure 2 ), and at the longitudinal other end (usually the rear end) of the frame 26, a pair of guide wheels 27 are installed. The drive wheels 19, 20 are driven by the traveling device described above with reference to Figure 1 . Each crawler 25 is driven by the corresponding drive wheels 19, 20 and guided by the corresponding guide wheels 27.

[0090] The present application further relates to a straight-line walking control method for a crawler chassis. This straight-line walking control method can achieve the straight-line walking of the crawler chassis. This straight-line walking control method can be applied to the above-mentioned reference Figure 1in the described traveling device or applied to a similar traveling device for a crawler chassis.

[0091] The crawler chassis to which the straight traveling control method of the present application is applicable includes a pair of drive wheels, referred to as a first drive wheel and a second drive wheel, and includes the hydraulic traveling drive system 2 described above.

[0092] An exemplary process of the straight traveling control method of the present application is shown in Figure 3 .

[0093] Referring to Figure 3 , in step S1, a longitudinal speed command (the vehicle traveling speed desired by the driver) is received.

[0094] Next, in step S2, the rotational speed of the first drive wheel, the rotational speed of the second drive wheel, and the lateral deflection angle of the crawler chassis are obtained in real time.

[0095] Next, in step S3, a reference drive signal is determined based on the longitudinal speed command and the rotational speed of the first drive wheel. After step S3 is completed, it proceeds to step S5.

[0096] Step S4 is executed in parallel with step S3.

[0097] Step S4 includes the following sub-steps:

[0098] In sub-step S41, a first correction value of the drive signal is generated based on the lateral deflection angle, and then it proceeds to sub-step S45;

[0099] Executed in parallel with sub-step S41: In sub-step S42, the lateral misalignment speed of the crawler chassis is determined based on the lateral deflection angle and the rotational speed of the second drive wheel; in sub-step S43, the lateral misalignment speed is accumulated to obtain the total lateral misalignment; in sub-step S44, a second correction value of the drive signal is generated based on the total lateral misalignment, and then it proceeds to sub-step S45;

[0100] In sub-step S45, the larger of the absolute values of the first correction value of the drive signal and the second correction value of the drive signal is used as the correction value of the drive signal. After sub-step S45 is completed, it proceeds to step S5.

[0101] In step S5, at least a first drive signal is generated based on the reference drive signal, and a second drive signal is generated based on the reference drive signal and the correction value of the drive signal.

[0102] Next, in step S6, the first drive signal is sent to the first proportional valve, and the second drive signal is sent to the second proportional valve. The first proportional valve is used to control the hydraulic oil supply of the hydraulic pump to the first hydraulic motor that drives the first drive wheel, and the second proportional valve is used to control the hydraulic oil supply of the hydraulic pump to the second hydraulic motor that drives the second drive wheel.

[0103] The implementation of the drive signal in the linear travel control method can refer to the corresponding description made above for the travel device, especially the linear travel controller 1. Therefore, the relevant features described above for the travel device, especially the linear travel controller 1, can be introduced into the linear travel control method and will not be described here again.

[0104] The crawler chassis travel device according to the present application performs closed-loop control on the rotational speed of the drive wheel by collecting the rotational speed and deflection information of the crawler chassis in real time, realizing the linear travel control function that is fully autonomously achieved without manual intervention, greatly reducing the labor intensity of the driver.

[0105] In addition, during the execution of closed-loop control, the feedback control signal (drive signal correction value) is determined based on both the lateral deflection angle (chassis angle deviation) and the total lateral misalignment (chassis lateral position deviation). Therefore, the control accuracy of this travel device is high and the control stability is good. Specifically, compared with the method of only correcting the rotational speed of the drive wheel using the lateral deflection angle, the present application takes into account the factor of vehicle speed (crawler chassis travel speed). When the vehicle speed is small, the lateral misalignment of the vehicle mainly depends on the magnitude of the lateral deflection angle. When the vehicle speed is large, the influence of the vehicle speed on the lateral misalignment of the vehicle increases, and even a small lateral deflection angle will cause a large lateral misalignment of the vehicle. Since the present application takes into account both the lateral deflection angle and the total lateral misalignment, and takes the larger value (absolute value) of the drive signal correction values determined based on the two, it can achieve high-precision and stable travel route control within various vehicle speed ranges.

[0106] In addition, a variety of detection signals (rotational speed sensor signal of the drive wheel, deflection angle sensor) are adopted in the controller of this travel device to adapt to various road conditions, ensuring that the speed and attitude of the vehicle are both well controlled.

[0107] Although the present application is described here with reference to specific embodiments, the scope of the present application is not limited to the details shown. Various modifications can be made to these details without departing from the basic principles of the present application.

Claims

1. A walking device for a crawler chassis, the crawler chassis comprising a crawler track driven by a first drive wheel (19) and a second drive wheel (20), the walking device comprising a linear walking controller (1) and a walking drive system (2); in, The travel drive system (2) comprises: a hydraulic pump (12); a first motor (17) for driving a first drive wheel (19) to rotate and a second motor (18) for driving a second drive wheel (20) to rotate; a first closed circuit for transmitting hydraulic oil between the hydraulic pump (12) and the first motor (17) and a second closed circuit for transmitting hydraulic oil between the hydraulic pump (12) and the second motor (18); a first electric proportional valve (13) for controlling a flow rate of the first closed circuit; and a second electric proportional valve (14) for controlling a flow rate of the second closed circuit; The straight line travel controller (1) is configured as follows: Receiving input longitudinal speed command; Real-time acquisition of the first driving wheel speed, the second driving wheel speed, and the lateral deflection angle of the crawler chassis; determining a reference drive signal based on the longitudinal speed command and the first drive wheel speed; generating a first correction value of the drive signal based on the lateral deflection angle; Determining the total amount of lateral misalignment of the crawler chassis based on the lateral deflection angle and the second drive wheel speed; generating a second correction value of the drive signal based on the total amount of lateral misalignment; The one with the larger absolute value between the first correction value of the driving signal and the second correction value of the driving signal is used as the correction value of the driving signal; generating a first drive signal and a second drive signal based on a reference drive signal and a drive signal correction value; and The opening degree of the first electric proportional valve (13) is controlled based on the first drive signal, and the opening degree of the second electric proportional valve (14) is controlled based on the second drive signal.

2. The walking device according to claim 1, wherein: The process for determining the total amount of lateral misalignment of the track undercarriage includes: The lateral displacement speed of the crawler chassis is obtained by multiplying the tangent value of the lateral deflection angle by the walking speed of the crawler chassis obtained based on the rotation speed of the second driving wheel, and the total amount of lateral displacement is obtained by integrating the lateral displacement speed with respect to time.

3. The walking device according to claim 1 or 2, wherein: The first driving signal is a reference driving signal, and the second driving signal is the reference driving signal plus a driving signal correction value.

4. The walking device according to any one of claims 1 to 3, wherein: The first driving signal is a reference driving signal k1*driving signal correction value, and the second driving signal is a reference driving signal plus k2*driving signal correction value, wherein k1 and k2 are correction coefficients.

5. The walking device according to claim 4, wherein: The value range of k1 and k2 is between 0 and 1; Optionally, k1+k2=1; For example: one of k1 and k2 is 0 and the other is 1, or both k1 and k2 are 0.5; Further optionally, 1 <k1+k2<1.5。 6. The walking device according to any one of claims 1 to 5, wherein: A deflection angle threshold is set in the linear travel controller (1), and a first correction value of the drive signal is generated only when the lateral deflection angle is greater than the deflection angle threshold.

7. The walking device according to any one of claims 1 to 6, wherein: A total offset threshold is set in the linear travel controller (1), and a second correction value of the drive signal is generated only when the total lateral misalignment is greater than the total offset threshold.

8. The walking device according to any one of claims 1 to 7, wherein: The hydraulic pump (12) is a constant pressure variable displacement pump; The travel drive system (2) further comprises a first compensation valve (15) and a second compensation valve (16), wherein the oil inlets of the first compensation valve (15) and the second compensation valve (16) are respectively connected to the output port of the hydraulic pump (12), the oil outlet of the first compensation valve (15) is connected to the oil inlet of the first electric proportional valve (13), and the first compensation valve (15) is configured to adjust the opening based on the system pressure feedback of the first closed loop, the oil outlet of the second compensation valve (16) is connected to the oil inlet of the second electric proportional valve (14), and the second compensation valve (16) is configured to adjust the opening based on the system pressure feedback of the second closed loop.

9. A method for controlling straight-line walking of a crawler chassis, the crawler chassis comprising: A crawler track driven by a first drive wheel (19) and a second drive wheel (20) respectively; Hydraulic pump (12); A first motor (17) for driving a first drive wheel (19) and a second motor (18) for driving a second drive wheel (20); a first closed circuit for transmitting hydraulic oil between a hydraulic pump (12) and the first motor (17) and a second closed circuit for transmitting hydraulic oil between the hydraulic pump (12) and the second motor (18); and a first electric proportional valve (13) for controlling a flow rate of the first closed circuit; and a second electric proportional valve (14) for controlling the flow rate of a second closed circuit; The straight line walking control method comprises: Receiving input longitudinal speed command; Real-time acquisition of the first driving wheel speed, the second driving wheel speed, and the lateral deflection angle of the crawler chassis; determining a reference drive signal based on the longitudinal speed command and the first drive wheel speed; generating a first correction value of the drive signal based on the lateral deflection angle; Determining the total amount of lateral misalignment of the crawler chassis based on the lateral deflection angle and the second drive wheel speed; generating a second correction value of the drive signal based on the total amount of lateral misalignment; The one with the larger absolute value between the first correction value of the driving signal and the second correction value of the driving signal is used as the correction value of the driving signal; generating a first drive signal and a second drive signal based on a reference drive signal and a drive signal correction value; and The opening degree of the first electric proportional valve (13) is controlled based on the first drive signal, and the opening degree of the second electric proportional valve (14) is controlled based on the second drive signal.

10. A crawler chassis system, comprising: A crawler chassis, the crawler chassis comprising: a first drive wheel (19) and a second drive wheel (20), and a crawler track (25) driven by the first drive wheel (19) and the second drive wheel (20) respectively; and The walking device according to any one of claims 1 to 8, used to drive the first driving wheel (19) and the second driving wheel (20) to rotate.

Images