Automatic two-speed control device, method for excavator travel motor and excavator

Abstract

The application discloses an automatic double-speed control device and method of an excavator walking motor and an excavator, and relates to the technical field of excavators, which comprises a man-machine interaction unit, a signal detection unit, a whole machine controller and a speed switching unit; the man-machine interaction unit is connected with the whole machine controller and is used for receiving a walking mode selection signal, including a high-speed mode instruction and a low-speed mode instruction; the signal detection unit comprises a pressure sensor arranged on a walking pilot oil circuit, and is connected with the whole machine controller and used for detecting a real-time walking pilot pressure value P; the speed switching unit is connected with the whole machine controller and is used for controlling the walking motor to switch between a high-speed state and a low-speed large-torque state; after receiving the high-speed mode instruction, the whole machine controller controls the walking motor to automatically switch the speed state according to the comparison result of the real-time walking pilot pressure value P and a preset pressure threshold value, so that the excavator can automatically reduce the speed and increase the torque when the excavator is blocked during high-speed walking.

Description

Technical Field

[0001] This invention relates to the field of excavator technology, and in particular to an automatic dual-speed control device, method, and excavator for an excavator travel motor. Background Technology

[0002] Existing dual-speed travel control for excavators is typically achieved by the operator manually switching between high and low speeds via a switch or knob. When the excavator moves from a flat surface into muddy, uphill, or rugged terrain, the operator needs to anticipate changes in travel resistance and manually reduce the speed. If the anticipation or operation is not timely, problems such as insufficient travel torque, getting stuck, chassis impact, or overall machine instability can easily occur at high speeds. Some existing automatic control schemes require the detection of parameters such as ground hardness, slope, or engine load, which suffers from complex sensor configurations, high system costs, complex control logic, and insufficient direct response to sudden changes in travel resistance.

[0003] Therefore, how to enable an excavator to automatically reduce speed and increase torque when encountering resistance while traveling at high speed is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic dual-speed control device, method, and excavator for the excavator's travel motor, which enables the excavator to automatically reduce speed and increase torque when encountering obstacles while traveling at high speed, thereby improving the overall passability of the machine and reducing the risk of getting stuck due to insufficient torque or chassis impact and instability due to excessive speed when traveling at high speed.

[0005] To achieve the above objectives, the present invention provides an automatic dual-speed control device for the travel motor of an excavator, comprising a human-machine interaction unit, a signal detection unit, a machine controller, and a speed switching unit; The human-machine interface unit is connected to the whole machine controller and is used to receive the driving mode selection signal input by the driver. The driving mode selection signal includes at least a high-speed mode command and a low-speed mode command. The signal detection unit includes a pressure sensor installed on the travel pilot oil circuit. The signal detection unit is connected to the whole machine controller and is used to detect the real-time travel pilot pressure value P and send it to the whole machine controller. The speed switching unit is connected to the whole machine controller and is used to control the walking motor to switch between high speed and low speed with high torque according to the control signal. The controller is configured to automatically switch the speed state of the walking motor after receiving a high-speed mode command, based on the comparison between the real-time walking pilot pressure value P and the preset pressure threshold.

[0006] In one possible implementation, the preset pressure threshold includes a preset high pressure threshold P_high and a preset low pressure threshold P_low, wherein P_low < P_high.

[0007] In one possible implementation, the controller is configured to: when it receives a high-speed mode command and detects a real-time walking pilot pressure value P≥P_high, output a low-speed control signal to the speed switching unit, so that the walking motor automatically switches from high-speed state to low-speed high-torque state.

[0008] In one possible implementation, the overall controller is further configured to: after the travel motor switches to a low-speed, high-torque state, when the real-time travel pilot pressure value P≤P_low is detected, output a high-speed control signal to the speed switching unit to restore the travel motor to a high-speed state.

[0009] In one possible implementation, a preset high pressure threshold P_high and a preset low pressure threshold P_low form a pressure hysteresis interval; when the real-time walking pilot pressure value P is within the pressure hysteresis interval, the whole machine controller keeps the control signal currently output to the speed switching unit unchanged.

[0010] In one possible implementation, the preset high pressure threshold P_high and the preset low pressure threshold P_low are calibrable parameters and are stored in the whole machine controller.

[0011] Based on the above, this application also provides an automatic dual-speed control method for an excavator travel motor, applicable to the automatic dual-speed control device for the excavator travel motor provided in the above embodiments. The automatic dual-speed control method for the excavator travel motor includes: Receives driving mode selection signals input by the driver, which include at least high-speed mode commands and low-speed mode commands; Detect the real-time travel pilot pressure value P in the excavator's travel pilot hydraulic circuit; When a low-speed mode command is received, a low-speed control signal is output to the speed switching unit to put the travel motor in a low-speed, high-torque state. When a high-speed mode command is received, the real-time walking pilot pressure value P is compared with the preset high pressure threshold P_high. When P≥P_high, a low-speed control signal is output to the speed switching unit, causing the travel motor to automatically switch from high-speed state to low-speed, high-torque state.

[0012] In one possible implementation, after the step of automatically switching the travel motor from a high-speed state to a low-speed, high-torque state, the following method is further included: Compare the real-time walking leader pressure value P with the preset low pressure threshold P_low; When P≤P_low, a high-speed control signal is output to the speed switching unit to restore the travel motor to high-speed state; Where P_low ≤ P_high.

[0013] In one possible implementation, after the step of automatically switching the travel motor from a high-speed state to a low-speed, high-torque state, the following method is further included: When the real-time walking pilot pressure value P is greater than P_low and less than P_high, the current speed of the walking motor remains unchanged.

[0014] Based on the above, this application also provides an excavator, including a travel motor, a travel pilot oil circuit, and an automatic dual-speed control device for the excavator travel motor as provided in the above embodiments. The signal detection unit includes a pressure sensor disposed on the travel pilot oil circuit, and the speed switching unit is connected to the speed switching control oil circuit of the travel motor.

[0015] Compared to existing technologies, the technical solution provided by this invention has at least the following beneficial effects: By setting up a human-machine interaction unit, a signal detection unit, a machine controller, and a speed switching unit, and by having the signal detection unit detect the real-time travel pilot pressure value P through a pressure sensor installed on the travel pilot oil circuit, the machine controller, upon receiving a high-speed mode command, can automatically control the travel motor to switch between high-speed and low-speed, high-torque states based on the comparison result between the real-time travel pilot pressure value P and a preset pressure threshold. Therefore, when the excavator encounters muddy roads, uphill sections, or rugged sections where travel resistance increases after the driver selects high-speed travel, the system can promptly identify the increased travel resistance based on changes in pilot pressure and automatically switch to low-speed, high-torque states, thereby improving the overall machine's passability and reducing the risk of getting stuck due to insufficient torque or chassis impact and instability due to excessive speed during high-speed travel. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This can be the overall system architecture diagram provided in the embodiments of the present invention; Figure 2 This can be the main control flowchart provided in the embodiments of the present invention; Figure 3 This can be a flowchart of the automatic speed reduction judgment subroutine provided in the embodiments of the present invention; Figure 4 This can be the flowchart of the automatic recovery judgment subroutine provided in the embodiments of the present invention; Figure 5 This can be the exception handling flowchart provided in the embodiments of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left" and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the position or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of this invention.

[0021] The purpose of this invention is to provide an automatic dual-speed control device, method, and excavator for the excavator's travel motor, which enables the excavator to automatically reduce speed and increase torque when encountering obstacles while traveling at high speed, thereby improving the overall passability of the machine and reducing the risk of getting stuck due to insufficient torque or chassis impact and instability due to excessive speed when traveling at high speed.

[0022] Please see Figures 1 to 5 , Figure 1 This can be the overall system architecture diagram provided in the embodiments of the present invention. Figure 2 This can be the main control flowchart provided in the embodiments of the present invention. Figure 3 This can be represented by the flowchart of the automatic speed reduction judgment subroutine provided in the embodiments of the present invention. Figure 4 This can be the flowchart of the automatic recovery judgment subroutine provided in the embodiments of the present invention. Figure 5 This can be the exception handling flowchart provided in the embodiments of the present invention.

[0023] To achieve the above objectives, the present invention provides an automatic dual-speed control device for the travel motor of an excavator, comprising a human-machine interaction unit, a signal detection unit, a machine controller, and a speed switching unit.

[0024] The human-machine interface (HMI) unit is connected to the main controller and is used to receive driving mode selection signals input by the driver. These signals include at least high-speed mode and low-speed mode commands. The HMI unit can be an HMI touchscreen display, control panel, buttons, knobs, or a combination thereof, located in the driver's cab. To improve ease of use, the HMI unit can also display the current driving status, automatic intervention status, alarm status, and threshold calibration status. For example, the HMI unit can display status information such as "Manual Low Speed," "Automatic High Speed," "Automatic Speed ​​Reduction," "Resumption of High Speed," and "Automatic Low Speed ​​Obstacle Encounter," allowing the driver to intuitively understand the current control status of the system.

[0025] In one specific implementation, the human-machine interface unit can also be equipped with an automatic / manual function selection entry. When the automatic function is enabled and the driver selects the high-speed mode, the controller enters the automatic intervention logic; when the automatic function is not enabled or the driver selects the low-speed mode, the controller can maintain the corresponding output according to the driver's selection. Through the above settings, the driver can retain the traditional operating habit of manually selecting high and low speeds, while also obtaining the intelligent assistance effect of automatic speed reduction when encountering obstacles in high-speed mode, thereby reducing the operational burden caused by frequent manual switching in complex road conditions.

[0026] The signal detection unit includes a pressure sensor installed on the travel pilot oil circuit. Connected to the main controller, the unit detects the real-time travel pilot pressure value P and sends it to the main controller. Since the travel pilot pressure directly reflects the driver's walking operation and changes in travel resistance, using it as the basis for automatic dual-speed control eliminates the need for additional complex detection components such as ground hardness sensors and slope sensors. This reduces system costs and improves the response speed to sudden changes in travel resistance.

[0027] Furthermore, the overall controller can sample and digitally filter the real-time travel pilot pressure signal output by the pressure sensor to eliminate the influence of pressure spikes, instantaneous impacts, or signal jitter on control decisions. Digital filtering can include moving average filtering, median filtering, amplitude limiting filtering, or a combination thereof. Through this processing method, the pressure judgment result obtained by the overall controller is more stable, avoiding unnecessary speed reduction of the travel motor due to instantaneous pressure spikes.

[0028] The speed switching unit is connected to the overall controller and is used to control the travel motor to switch between high-speed and low-speed, high-torque states based on control signals. It should be noted that in this embodiment, "high-speed state" refers to the travel motor operating at a higher travel speed; "low-speed, high-torque state" refers to the travel motor operating at a higher traction or output torque. These states can be achieved by controlling the travel motor's speed switching control hydraulic circuit through the speed switching unit. The overall controller can output PWM signals, switching signals, or other control signals suitable for driving the solenoid valve to the speed switching unit. The speed switching unit changes the hydraulic state of the speed switching control hydraulic circuit according to the control signal, causing the travel motor to switch between high-speed and low-speed, high-torque states. Thus, the electronic control signal and the hydraulic actuator form a closed-loop coordination, enabling the automatic judgment result of the overall controller to be promptly translated into changes in the travel motor's speed state.

[0029] The controller is configured to automatically switch the speed state of the walking motor after receiving a high-speed mode command, based on the comparison between the real-time walking pilot pressure value P and the preset pressure threshold.

[0030] By incorporating a human-machine interface unit, a signal detection unit, a machine controller, and a speed switching unit, and by having the signal detection unit detect the real-time travel pilot pressure value P via a pressure sensor installed on the travel pilot hydraulic circuit, the machine controller, upon receiving a high-speed mode command, can automatically control the travel motor to switch between high-speed and low-speed, high-torque modes based on a comparison between the real-time travel pilot pressure value P and a preset pressure threshold. Therefore, when the excavator encounters muddy roads, uphill sections, or rugged terrain where travel resistance increases after the operator selects high-speed travel, the system can promptly identify the increased travel resistance based on changes in pilot pressure and automatically switch to low-speed, high-torque mode. This improves the machine's passability and reduces the risk of getting stuck due to insufficient torque or experiencing chassis impact and instability due to excessive speed during high-speed travel.

[0031] In one possible implementation, the preset pressure thresholds include a preset high pressure threshold P_high and a preset low pressure threshold P_low, where P_low < P_high. That is, P_high is always greater than P_low, and the two are not equal. P_high is used to determine whether the excavator encounters significant travel resistance in high-speed mode, while P_low is used to determine whether the travel resistance has decreased to a level sufficient to resume high speed after automatic deceleration.

[0032] In one possible implementation, a preset high pressure threshold P_high and a preset low pressure threshold P_low are calibrable parameters and stored in the machine controller. Specifically, P_high and P_low can be factory-calibrated or after-sales calibrated according to the hydraulic system pressure range, travel motor characteristics, overall machine weight, track structure, typical working scenarios, and driver operating habits of different excavator models. The machine controller reads the preset parameters after the system is powered on and calls these parameters for comparison and judgment in the main loop. By setting P_high and P_low as calibrable parameters, this invention can adapt to excavators of different tonnages, different hydraulic configurations, and different usage scenarios.

[0033] In one possible implementation, when the driver inputs a high-speed mode command through the human-machine interface unit, the machine controller enters an automatic intervention state. In this state, the machine controller continuously reads the real-time travel pilot pressure value P detected by the pressure sensor and compares P with a preset high-pressure threshold P_high. The machine controller is configured to: upon receiving a high-speed mode command and detecting a real-time travel pilot pressure value P ≥ P_high, output a low-speed control signal to the speed switching unit, causing the travel motor to automatically switch from high-speed to low-speed, high-torque mode. When the machine controller detects P ≥ P_high, it determines that the current travel resistance is too high. For example, when the excavator moves from a flat, hard surface to a muddy surface, soft ground, an uphill section, or a rugged section, the travel resistance increases, and the travel pilot oil circuit pressure rises accordingly. When this pressure rises to P_high or higher, the machine controller outputs a low-speed control signal to the speed switching unit, causing the travel motor to automatically switch from high-speed to low-speed, high-torque mode.

[0034] To further improve the reliability of automatic speed reduction judgment, the controller can perform multiple consecutive confirmations after detecting P≥P_high. That is, a low-speed control signal is only output when the real-time travel pilot pressure value P satisfies P≥P_high in N consecutive samplings. Here, N is an integer greater than or equal to 1; for example, N can be 5, and can be calibrated according to sampling period and response speed requirements. Through N consecutive detection confirmations, single pressure spikes can be filtered out, making the automatic speed reduction action both rapid and reliable.

[0035] When outputting low-speed control signals, the controller can also record current operating condition data, including but not limited to the time of automatic speed reduction, real-time travel pilot pressure values ​​P, P_high, and P_low, current travel mode, current speed status, and fault status. Recording this data facilitates subsequent fault diagnosis, control parameter optimization, and traceability of the machine's operating status.

[0036] After the travel motor completes automatic speed reduction, the human-machine interface unit can display the automatic speed reduction status, indicating to the driver that the system has automatically switched from high-speed mode to low-speed, high-torque mode. In this way, when the driver selects high-speed travel, the excavator can automatically increase its traction capacity when encountering a sudden increase in resistance, improving overall machine passability and reducing the risk of getting stuck due to insufficient torque at high speeds. It also reduces the risk of chassis impact and overall machine instability caused by excessive speed when entering complex terrain.

[0037] In one possible implementation, the controller is further configured to: after the walking motor switches to a low-speed, high-torque state, when the real-time walking pilot pressure value P≤P_low is detected, determine that the current walking resistance has decreased, and output a high-speed control signal to the speed switching unit to restore the walking motor to a high-speed state.

[0038] In one specific implementation, the machine controller starts a timer T after automatic speed reduction and sets a minimum low-speed holding time T_min. The machine controller only executes automatic high-speed recovery control when the duration T of the travel motor being in a low-speed, high-torque state reaches T_min, and the real-time travel pilot pressure value P satisfies P≤P_low. T_min can be a calibrable parameter. By setting a minimum low-speed holding time, it avoids immediate resumption of high speed immediately after speed reduction due to a brief drop in pressure, thereby further reducing the possibility of frequent switching.

[0039] Furthermore, before resuming high speed, the controller can determine whether the pressure fluctuation is within the allowable range. If the real-time travel pilot pressure value P is lower than or equal to P_low, but the pressure fluctuation is still significant, the controller can temporarily withhold high speed and continue maintaining a low-speed, high-torque state while re-detecting the pressure. Only when the pressure fluctuation is within the allowable range will the high-speed control signal be output. This method makes the high-speed recovery smoother and reduces sudden speed changes under complex road conditions.

[0040] After the overall controller outputs a high-speed control signal, it can further detect the feedback signal of the speed switching unit or the system status to verify whether the high-speed recovery action has been completed normally. If the recovery effect is normal, the overall controller records the automatic recovery success information and displays the high-speed recovery status in the human-machine interface unit; if the recovery effect is abnormal, it enters the abnormal handling process. Through the above recovery judgment and verification process, the present invention can not only automatically reduce speed and increase torque when encountering obstacles, but also automatically restore high speed after the resistance decreases, thereby achieving the walking control effect of high-speed cruising, automatic speed reduction when encountering obstacles, and automatic recovery after getting out of trouble.

[0041] In one possible implementation, a pressure hysteresis interval is formed by pre-setting a high pressure threshold P_high and a pre-setting low pressure threshold P_low. When the real-time travel pilot pressure value P is within the pressure hysteresis interval, the overall controller maintains the current control signal output to the speed switching unit unchanged. In other words, if the travel motor is currently in a high-speed state, it will maintain the high-speed state until P reaches P_high; if the travel motor has automatically switched to a low-speed, high-torque state, it will maintain the low-speed, high-torque state until P decreases to P_low. By setting this pressure hysteresis interval, the frequent switching between high-speed and low-speed, high-torque states by the travel motor can be avoided when the pilot pressure value P fluctuates around a single threshold, thereby improving control stability and driving comfort.

[0042] When the driver inputs a low-speed mode command through the human-machine interface, the machine controller outputs a low-speed control signal to the speed switching unit, putting the travel motor in a low-speed, high-torque state. In this mode, the machine controller can continuously maintain the low-speed control signal and display the manual low-speed status on the human-machine interface. By retaining the low-speed mode command, the driver can directly select the low-speed, high-torque state when a greater traction force is clearly required, such as short-distance movement before loading, walking on slopes, walking on slippery surfaces, or delicate operations in narrow spaces.

[0043] When the driver selects high-speed mode and the travel motor is at high speed, if the real-time travel pilot pressure value P is less than P_high, the controller will not perform automatic speed reduction and will maintain the high-speed control signal. Once the travel motor has automatically reduced to a low-speed, high-torque state, if the real-time travel pilot pressure value P is greater than P_low and less than P_high, the controller will maintain the low-speed control signal. This control logic ensures that the pressure hysteresis range not only has an anti-shake effect but also maintains the continuity of the travel state perceived by the driver.

[0044] Based on the above, this application also provides an automatic dual-speed control method for an excavator travel motor, applicable to the automatic dual-speed control device for the excavator travel motor provided in the above embodiments. The automatic dual-speed control method for the excavator's travel motor includes: Receives driving mode selection signals input by the driver, which include at least high-speed mode commands and low-speed mode commands; Detect the real-time travel pilot pressure value P in the excavator's travel pilot hydraulic circuit; When a low-speed mode command is received, a low-speed control signal is output to the speed switching unit to put the travel motor in a low-speed, high-torque state. When a high-speed mode command is received, the real-time walking pilot pressure value P is compared with the preset high pressure threshold P_high. When P≥P_high, a low-speed control signal is output to the speed switching unit, so that the walking motor automatically switches from high-speed state to low-speed high-torque state. Compare the real-time walking leader pressure value P with the preset low pressure threshold P_low; When P ≤ P_low, a high-speed control signal is output to the speed switching unit to restore the travel motor to high-speed state, where P_low ≤ P_high.

[0045] When the real-time walking pilot pressure value P is greater than P_low and less than P_high, the current speed of the walking motor remains unchanged.

[0046] This control method can be executed periodically by the overall controller. Specifically, after the system powers on, the overall controller initializes and reads preset parameters stored in the overall controller. The preset parameters include at least P_high, P_low, sampling period, number of consecutive acknowledgments N, and minimum low-speed hold time T_min. Subsequently, the overall controller enters the main loop, periodically reading the mode setting signal from the human-machine interface unit and the real-time walking pilot pressure value P output by the pressure sensor.

[0047] Specifically, after the system powers on, the controller initializes and reads preset parameters stored in the controller. These preset parameters include at least P_high, P_low, sampling period, number of consecutive confirmations N, and minimum low-speed hold time T_min. Subsequently, the controller enters the main loop, periodically reading the mode setting signal from the human-machine interface unit and the real-time walking pilot pressure value P output by the pressure sensor.

[0048] When the machine controller receives a low-speed mode command, it outputs a low-speed control signal to the speed switching unit, putting the walking motor in a low-speed, high-torque state, and updates the display status in the human-machine interaction unit.

[0049] When the controller receives a high-speed mode command, it enters automatic intervention mode and determines the current speed of the travel motor. If the current speed is high, the controller compares the real-time travel pilot pressure value P with P_high. If P ≥ P_high, or if P satisfies P ≥ P_high in N consecutive samples, the controller outputs a low-speed control signal, automatically switching the travel motor from high-speed to low-speed, high-torque mode. If P does not reach P_high, the controller maintains the high-speed mode.

[0050] If the current state is low-speed, high-torque, the controller compares the real-time travel pilot pressure value P with P_low. When P ≤ P_low, the low-speed duration T reaches T_min, and the pressure fluctuation is within the allowable range, the controller outputs a high-speed control signal to restore the travel motor to high-speed mode. If P is greater than P_low but less than P_high, or T does not reach T_min, or the pressure fluctuation is not within the allowable range, the controller maintains the low-speed, high-torque state.

[0051] Before the end of each control cycle, the machine controller can wait for a preset cycle time Δt and perform a system fault check. If no fault is found, the next control cycle begins; if a fault is detected, the exception handling process begins. By periodically executing the above steps, automatic dual-speed control of the excavator's travel motor can be achieved without changing the operator's regular walking habits.

[0052] To improve system reliability, this embodiment can also include an anomaly handling process. The anomaly handling process may include handling anomalies related to the pressure sensor, speed switching unit, power supply voltage, and logic state.

[0053] When the controller detects an abnormal pressure sensor signal, such as a pressure signal exceeding the reasonable range, signal loss, short circuit, open circuit, or pressure change not conforming to actual operating conditions, the controller can trigger sensor fault handling. Sensor fault handling may include at least one of the following: using a default pressure value, switching to manual mode, or issuing an alarm notification via the human-machine interface. This method prevents the system from frequently or incorrectly switching the travel motor speed based on erroneous pressure signals, even if the pressure detection signal is abnormal.

[0054] When the overall controller detects an abnormal response from the speed switching unit, such as when a control signal has been output but no corresponding feedback is detected, or when the solenoid valve feedback is inconsistent with the target state, the overall controller can trigger solenoid valve fault handling. Solenoid valve fault handling can include at least one of the following: resending the control command, cutting off the output, locking the current gear, and issuing an alarm notification via the human-machine interface. This method can reduce the impact of actuator malfunctions on the overall machine's operational safety.

[0055] When the controller detects an abnormal power supply voltage, it can record the voltage value, save the current control status data, and perform a soft shutdown or enter a safe mode if necessary. Recording the voltage value and saving the status data facilitates subsequent troubleshooting of power system faults; entering a safe mode prevents the controller from outputting unreliable control signals under unstable power supply conditions.

[0056] When the overall controller detects a logical state conflict, such as an inconsistency between the current state, the target state, and the feedback state, it can trigger logical fault handling. Logical fault handling can include resetting the state machine, restoring default parameters, and reinitializing. These self-recovery measures improve the stability of the control program and reduce the likelihood of erroneous outputs due to abnormal software states.

[0057] Based on the above, this application also provides an excavator, including a travel motor, a travel pilot oil circuit, and an automatic dual-speed control device for the excavator travel motor as provided in the above embodiments. The signal detection unit includes a pressure sensor disposed on the travel pilot oil circuit, and the speed switching unit is connected to the speed switching control oil circuit of the travel motor. It is used to control the travel motor to switch between a high-speed state and a low-speed, high-torque state according to the control signal output by the machine controller.

[0058] By equipping the excavator with the aforementioned automatic dual-speed control device, the operator can select high-speed mode to improve travel efficiency on flat roads or during routine site transfers. When the excavator encounters mud, slopes, soft ground, or rugged terrain during high-speed travel, causing increased travel resistance, the machine controller automatically outputs a low-speed control signal based on changes in the travel pilot pressure, switching the travel motor to a low-speed, high-torque state. When the travel resistance decreases, the machine controller automatically resumes high-speed mode based on the judgment result that P ≤ P_low. Thus, the excavator can balance high-speed travel efficiency with the ability to navigate complex working conditions.

[0059] In summary, this invention, through the coordination of the human-machine interface unit, signal detection unit, machine controller, and speed switching unit, uses the travel pilot pressure value P as the basis for judging changes in travel resistance, and combines the pressure hysteresis interval formed by P_high and P_low to achieve automatic speed reduction and automatic recovery in high-speed mode. This solution has a simple structure, clear control logic, and rapid response. It does not require complex ground condition detection components, which helps reduce system costs and improves the excavator's passability, stability, and operational safety in complex road conditions.

[0060] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of the present invention. It should be pointed out that those skilled in the art can make several improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. An automatic dual-speed control device for an excavator's travel motor, characterized in that, It includes a human-computer interaction unit, a signal detection unit, a whole machine controller, and a speed switching unit; The human-machine interaction unit is connected to the whole machine controller and is used to receive the driving mode selection signal input by the driver. The driving mode selection signal includes at least a high-speed mode command and a low-speed mode command. The signal detection unit includes a pressure sensor installed on the travel pilot oil circuit. The signal detection unit is connected to the whole machine controller and is used to detect the real-time travel pilot pressure value P and send it to the whole machine controller. The speed switching unit is connected to the whole machine controller and is used to control the walking motor to switch between high speed and low speed high torque state according to the control signal. The overall controller is configured to: upon receiving the high-speed mode command, control the walking motor to automatically switch speed states based on the comparison result between the real-time walking pilot pressure value P and the preset pressure threshold.

2. The automatic dual-speed control device for the excavator travel motor according to claim 1, characterized in that, The preset pressure thresholds include a preset high pressure threshold P_high and a preset low pressure threshold P_low, wherein P_low < P_high.

3. The automatic dual-speed control device for the excavator travel motor according to claim 2, characterized in that, The overall controller is configured to: when it receives the high-speed mode command and detects that the real-time walking pilot pressure value P≥P_high, output a low-speed control signal to the speed switching unit, so that the walking motor automatically switches from high-speed state to low-speed high-torque state.

4. The automatic dual-speed control device for the excavator travel motor according to claim 3, characterized in that, The overall controller is also configured to: after the walking motor switches to a low-speed, high-torque state, when the real-time walking pilot pressure value P ≤ P_low is detected, output a high-speed control signal to the speed switching unit to restore the walking motor to a high-speed state.

5. The automatic dual-speed control device for the excavator travel motor according to claim 2, characterized in that, The preset high pressure threshold P_high and the preset low pressure threshold P_low form a pressure hysteresis interval; when the real-time walking pilot pressure value P is within the pressure hysteresis interval, the whole machine controller keeps the control signal currently output to the speed switching unit unchanged.

6. The automatic dual-speed control device for the excavator travel motor according to claim 2, characterized in that, The preset high pressure threshold P_high and the preset low pressure threshold P_low are calibrable parameters and are stored in the whole machine controller.

7. An automatic dual-speed control method for an excavator travel motor, applicable to the automatic dual-speed control device for an excavator travel motor as described in any one of claims 1 to 6, characterized in that, include: Receives a driving mode selection signal input by the driver, wherein the driving mode selection signal includes at least a high-speed mode command and a low-speed mode command; Detect the real-time travel pilot pressure value P in the excavator's travel pilot hydraulic circuit; When the low-speed mode command is received, a low-speed control signal is output to the speed switching unit to put the walking motor in a low-speed, high-torque state. When the high-speed mode command is received, the real-time walking pilot pressure value P is compared with the preset high pressure threshold P_high; When P≥P_high, a low-speed control signal is output to the speed switching unit, causing the walking motor to automatically switch from high-speed state to low-speed, high-torque state.

8. The automatic dual-speed control method for the excavator travel motor according to claim 7, characterized in that, Following the step of automatically switching the travel motor from high-speed to low-speed, high-torque mode, the following also applies: The real-time walking leader pressure value P is compared with a preset low pressure threshold P_low; When P≤P_low, a high-speed control signal is output to the speed switching unit to restore the walking motor to high-speed state; Where P_low ≤ P_high.

9. The automatic dual-speed control method for the excavator travel motor according to claim 8, characterized in that, Following the step of automatically switching the travel motor from high-speed to low-speed, high-torque mode, the following also applies: When the real-time walking pilot pressure value P is greater than P_low and less than P_high, the current speed of the walking motor remains unchanged.

10. An excavator, characterized in that, The device includes a travel motor, a travel pilot oil circuit, and an automatic dual-speed control device for the excavator travel motor as described in any one of claims 1 to 6. The signal detection unit includes a pressure sensor disposed on the travel pilot oil circuit, and the speed switching unit is connected to the speed switching control oil circuit of the travel motor.

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