Lifting control system and control method of unmanned mine car

Abstract

The invention relates to the technical field of automatic control of unmanned mine cars, in particular to a lifting control system and method for an unmanned mine car, and the system comprises a mechanical displacement travel switch which is connected to an automatic driving controller; the backward laser radar is used for acquiring the laser point cloud clustering projection area of the tail part of the container; a time counter; the automatic driving controller is in signal connection with the backward laser radar and the time counter and is used for obtaining the ascending starting state and the descending in-place state of the container through the mechanical displacement travel switch. And the processor is also used for determining the state of the highest point of the container and obtaining the keeping calibration duration of the highest point of the container when the time of the time counter is greater than or equal to the corresponding calibration duration, and the laser point cloud clustering projection area is close to the maximum projection area and / or the rotating speed change rate of the engine exceeds a set threshold value. According to the lifting control system and the lifting control method, the technical problem that a lifting system of an unmanned mine car is poor in reliability is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control of driverless mining trucks, and particularly relates to a lifting control system and a control method for a driverless mining truck. Background Art

[0002] At present, automatic driverless dump trucks are mainly used for unattended automated operations of ores and muck underground or at construction sites; in the usage environment, it is necessary to automatically lift and control the dump truck for unloading. In the unmanned operation project, it is necessary to automatically judge whether the unloading is completed, whether the cargo box reaches the maximum lifting stroke, and whether the cargo box descends in place when descending; when the traditional vehicle is manually driven, the driver observes on-site and manually controls the up and down stroke of the cargo box through the lifting switch. However, for driverless engineering vehicles, they need to be in an unattended state without manual judgment of the environment, and rely on the autonomous driving system to independently judge whether the lifting is working safely. There are the following several potential safety hazards in the autonomous judgment of the autonomous driving system:

[0003] ① If the lifting is ended when the cargo box does not reach the maximum stroke, it will cause the ore in the cargo box not to be completely dumped, affecting work production efficiency; at the same time, if the lifting continues to be controlled repeatedly after reaching the maximum stroke, it will cause the unloading time to be too long. Repeatedly requesting the lifting work at the maximum stroke will cause the oil pressure system of the lifting pump to work fatigued, and at the same time, the transmission and the engine power system will also consume more fuel.

[0004] ② During the descent of the cargo box, how to judge whether the cargo box descends to the lowest point and whether it lands safely is also a difficult problem that needs to be solved by driverless dump trucks; if the empty cargo box does not land safely and the carriage is still in an inclined state when driving on a bumpy construction site, it will dump the remaining stone slag in the main road driving area. At the same time, the unsafe landing of the cargo box will also pose potential safety hazards during driving. For example, if the cargo box does not land, the tipping bucket of the cargo box is higher than the cab of the truck's head. In the underground operation scenario, the height of the mine is relatively low, and the tipping bucket of the cargo box will get stuck on the top of the underground mine, causing vehicle damage; especially underground, above the vehicle during driving, there are usually high-voltage circuits and some ventilation pipelines arranged and routed. The overly high cargo box will scrape against the top surface of the mine, causing damage to the high-voltage circuits and ventilation pipes, posing a serious potential safety hazard to underground production safety.

[0005] In the related art, in order to solve the problem of the lifting stroke of the driverless cargo box, the current solution is to install a forward lidar 3 at the root of the lifting device 2 at the bottom of the cargo box (see Figure 1 ) for ranging. The emission direction of the lidar is vertically upward, and the stroke displacement state of the cargo box is detected in real time. The lidar detects the displacement in real time and performs a closed-loop real-time control, which has the characteristics of accurate detection and good real-time performance.

[0006] However, the current solutions have poor reliability and are not suitable for harsh working conditions. Specifically, the working environment of engineering vehicles is harsh, such as construction sites, surface and underground coal mine shafts, etc. The working environment is full of dust, flying ash, and coal slag. Especially in the underground mine operation environment, it is humid. The forward lidar is easily blocked by dust and water vapor. At the same time, since the displacement of the cargo box is a vertical displacement relative to the ground, the laser lens of the forward lidar needs to be directed vertically upward, which makes it easier to increase the probability of coverage of the lens by dust, rain, snow, dew, etc., resulting in the failure and distortion of the displacement detection of the cargo box. In this way, it is impossible to ensure the long-term reliable and normal operation of the unmanned lifting system, and the reliability is poor. Summary of the Invention

[0007] The present application provides a lifting control system and a control method for an unmanned mining vehicle, which solve the technical problem of poor reliability of the lifting system of the unmanned mining vehicle.

[0008] In a first aspect, an embodiment of the present application provides a lifting control system for an unmanned mining vehicle, including:

[0009] A mechanical displacement travel switch, which is arranged at the junction of the tail of the cargo box and the tail of the chassis and is connected to the autonomous driving controller in a normally open state; the mechanical displacement travel switch is used to trigger a high level when the lifting device starts to work, and is also used to trigger a low level when the lifting device descends to the in-place state;

[0010] A rear lidar, whose laser emission direction is horizontally backward, is used to obtain the laser point cloud clustering projection area of the tail of the cargo box;

[0011] A time counter, which is used to obtain the time of the cargo box rising, staying at the highest point, and descending;

[0012] The autonomous driving controller is respectively connected to the rear lidar and the time counter by signals. The autonomous driving controller is used to obtain the start-rising state and the descending-in-place state of the cargo box through the mechanical displacement travel switch, and is also used to determine the highest-point state of the cargo box and obtain the holding calibration duration of the highest point of the cargo box when the time of the time counter is greater than or equal to the corresponding calibrated duration, and the laser point cloud clustering projection area is close to the maximum projection area and / or the engine speed change rate exceeds the set threshold.

[0013] In combination with the first aspect, in an implementation manner, the highest-point state of the cargo box simultaneously satisfies that the time of the time counter is greater than or equal to the rising calibration duration and the laser point cloud clustering projection area is close to the maximum projection area; the rising calibration duration and the holding calibration duration are calibrated in advance according to the standard load of the cargo box obtained by the autonomous driving controller.

[0014] In combination with the first aspect, in an implementation manner, the highest-point state of the cargo box simultaneously satisfies that the time of the time counter is greater than or equal to the rising calibration duration and the engine speed change rate exceeds the set threshold.

[0015] Combined with the first aspect, in one embodiment, the highest point state of the cargo box is determined by simultaneously satisfying that the time of the time counter is greater than or equal to the rising calibration duration, the laser point cloud clustering projection area is close to the maximum projection area, and the engine speed change rate exceeds the set threshold.

[0016] Combined with the first aspect, in one embodiment, a limit protection switch is provided at the maximum stroke of the telescopic part of the lifting device. After the limit protection switch is triggered to work, the engine speed decreases. When the engine speed change rate exceeds the set threshold, it is determined that one of the conditions for the cargo box to reach the highest point state is met.

[0017] Combined with the first aspect, in one embodiment, the laser point cloud clustering projection area is proportional to the lifting height of the cargo box. The laser point cloud clustering projection area being close to the maximum projection area includes:

[0018] |Smax - Scur| ≤ s1, where Scur is the laser point cloud clustering projection area of the tail of the cargo box during unloading obtained by the autonomous driving controller through the rear lidar in real time, Smax is the laser point cloud clustering projection area of the highest point of the cargo box calibrated in advance, and s1 is the projection difference threshold set in advance.

[0019] Combined with the first aspect, in one embodiment, the time of the time counter corresponding to the calibration duration includes the lifting calibration duration time_up_crr to reach the highest point and the holding calibration duration time_hold_crr to stay at the highest point;

[0020] time_up_crr = time_up + ((m1 - m) / m) * x_Time_up1;

[0021] where m is the standard load of the cargo box, time_up is the time for the cargo box to be lifted to the highest point when the standard load is m, m1 is the cargo box load value of the driverless mining truck obtained by the autonomous driving controller; x_Time_up1 is the lifting rise correction time coefficient obtained by looking up the table according to m1;

[0022] time_hold_crr = time_hold + ((m1 - m) / m) * x_Time_hold1;

[0023] where time_hold is the unloading time for the cargo box to stay at the highest point when the standard load is m, and x_Time_hold1 is the lifting holding correction time coefficient obtained by looking up the table according to m1.

[0024] In combination with the first aspect, in one implementation, the engine speed change rate may also be replaced by a numerical decrease rate of the variable transmission output torque or the transmission oil pressure.

[0025] In a second aspect, the present application discloses a control method based on the above-mentioned lifting control system, comprising the steps of:

[0026] The lifting device starts lifting, and the mechanical displacement travel switch triggers a high-level signal to the automatic driving controller, and the automatic driving controller learns that the cargo box starts to rise;

[0027] The cargo box rises until the time counter is greater than or equal to the rising calibration time, and the laser point cloud cluster projection area is close to the maximum projection area and / or the engine speed change rate exceeds the set threshold, confirming that the cargo box has reached the highest point;

[0028] The unloading is carried out by lifting and holding until the time counter is greater than or equal to the holding calibration time, and the cargo box starts to descend; wherein the lifting calibration time and the holding calibration time are obtained in advance according to the cargo box standard load calibration obtained by the automatic driving controller;

[0029] It descends until the mechanical displacement travel switch triggers a low-level signal to the automatic driving controller, and the cargo box reaches the lowered position.

[0030] In combination with the second aspect, in one embodiment, the highest point state of the cargo box is confirmed based on the time of the time counter being greater than or equal to the ascending calibration duration and the laser point cloud clustering projection area being close to the maximum projection area;

[0031] Alternatively, the highest point state of the cargo box is confirmed based on the time of the time counter being greater than or equal to the rising calibration time and the engine speed change rate exceeding a set threshold;

[0032] Alternatively, the highest point state of the cargo box is determined based on a combination of the time of the time counter being greater than or equal to the rising calibration duration, the laser point cloud clustering projection area being close to the maximum projection area, and the engine speed change rate exceeding a set threshold.

[0033] The beneficial effects brought by the technical solution provided by the embodiment of the present application include at least:

[0034] 1. The lifting control system of this application is different from the prior art solution which uses laser ranging for real-time continuous monitoring of the lifting stroke of the cargo box in a closed-loop control. This application adopts an open-loop control of the lifting stroke and lifting time, without real-time detection of the lifting stroke for open-loop control. The autonomous driving controller is used to obtain the starting rising state and the descending-in-place state of the cargo box through a mechanical displacement travel switch, and is also used to confirm the state of the cargo box reaching the highest point and obtain the holding time at the highest lifting point by the time of the time counter being greater than or equal to the calibrated rising duration, combined with the laser point cloud clustering projection area and / or the engine speed change rate. Based on this, it guides the lifting control system to control the starting rising state, reaching the highest point state, holding at the highest point for a period of time, and descending-in-place state of the cargo box, achieving the purpose of reliably and safely controlling the lifting and lowering of the cargo box of an unmanned mining truck. Compared with the closed-loop control of continuous real-time monitoring in the prior art solution, the lifting control system of this application ignores the whole process and only focuses on important nodes, is not affected by harsh environments, solves the technical problem of poor reliability of the lifting system of an unmanned mining truck, and reduces the energy consumption of the lifting control system. The lifting control system of this application only needs to add a mechanical displacement travel switch, a rear lidar, and a time counter. Even the rear lidar can use the built-in positioning lidar, with a simple structure, low cost, and high reliability.

[0035] 2. For the lifting control system of this application, three features are used for redundant judgment in the judgment of the highest point state during the rising stage of the cargo box lifting, namely ① the laser point cloud clustering projection area of the rear lidar, ② the pre-calibrated engine speed change rate, and ③ the pre-calibrated time of the time counter. The three features are combined to judge the highest point state, which can reliably and accurately determine the highest point state of the cargo box. Compared with the prior art solution that only relies on a forward lidar, it is more reliable and stable.

[0036] 3. For the lifting control system of this application, according to the working characteristics of the lifting device, when the lifting reaches the highest point, the limit protection switch will be triggered, which in turn triggers the unloading of the lifting hydraulic system, thereby causing a decrease in the engine speed. Using the characteristic of the engine speed change rate as one of the characteristic judgments for the highest point of the lifting stroke, when the autonomous driving controller detects that the corresponding engine speed change rate exceeds the pre-set threshold and meets the characteristic requirements, the lifting control system will then change the lifting control state from the lifting rising request to the lifting holding request. Using the engine speed change rate characteristic as the characteristic judgment for the highest point of the lifting stroke is ingeniously designed and lays a foundation for the reliability of the lifting system.

[0037] 4. In the lifting control system of this application, to ensure the detection safety and reliability at the highest point of the cargo box, a rear lidar is added to perform laser point cloud clustering detection on the tail of the cargo box. During the lifting process, the laser point cloud clustering area of the tail of the cargo box appearing in the rear lidar is proportional to the lifting height of the cargo box. Based on this feature, it is judged whether the cargo box reaches the highest point. When the cargo box is lifted, when the cargo box is approaching the highest point during the rising process, it will appear within the detection range of the rear lidar. The rear lidar calculates the projected area of the laser point cloud clustering on the tail of the cargo box when unloading the cargo box. Since the lifting height of the cargo box is proportional to this area, the laser point cloud detection area in the state where the cargo box is lifted to the highest point is calculated in advance to obtain Smax. During the unloading process, the real-time detected projected area of the laser point cloud on the tail of the cargo box is Scur. If |Smax - Scur| ≤ s1, it is considered that the cargo box meets one of the conditions for the highest point state.

[0038] 5. The control method of this application does not detect the lifting stroke in real time. It obtains the state that the cargo box starts to rise through the high level triggered by the mechanical displacement stroke, and confirms that the cargo box reaches the highest point state through three redundant features, that is, the time of the time counter is greater than or equal to the rising calibration duration, and the laser point cloud clustering projected area is close to the maximum projected area and / or the engine speed change rate exceeds the set threshold; the holding duration at the highest point of the cargo box is determined by the time of the time counter being greater than or equal to the holding calibration duration; the state that the cargo box reaches the lowered position is confirmed through the low level of the mechanical displacement stroke switch. According to the guiding lifting control system, the start-up state, the state of reaching the highest point, the state of staying at the highest point for a period of time, and the state of reaching the lowered position of the cargo box are controlled, so as to achieve the purpose of reliably and safely controlling the lifting of the cargo box of the driverless mining vehicle. Compared with the closed-loop control of continuous real-time monitoring in the prior art solution, the lifting control system of this application solves the technical problem of poor reliability of the lifting system of the driverless mining vehicle, and ignores the whole process and only focuses on the important nodes, reducing the energy consumption of the lifting control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0040] Figure 1 It is a schematic diagram of the lifting stroke of a traditional driverless cargo box;

[0041] Figure 2 It is a schematic diagram of the structure of the automatically lifted cargo box provided by the embodiment of this application;

[0042] Figure 3 For Figure 2Partial enlarged view of A therein;

[0043] Figure 4 Laser point cloud map of the tail of the cargo box detected by the rear lidar provided by the embodiment of the present application;

[0044] Figure 5 Electrical diagram of the automatic lifting cargo box stroke detection provided by the embodiment of the present application;

[0045] Figure 6 Provided by the embodiment of the present application;

[0046] In the figure: 1, cargo box; 2, lifting device; 3, forward lidar; 4, chassis frame; 10, mechanical displacement travel switch; 11, rear lidar; 12, time counter. Detailed implementation manner

[0047] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0048] The lifting control system of the present application. This patent does not care about the real-time control of the lifting stroke of the cargo box, but focuses on ensuring the control of the start and the highest stroke points of the lifting, is not affected by harsh environments, has high reliability, is simple to implement, and solves the technical problem of poor reliability of the lifting system of driverless mining trucks.

[0049] As Figures 1 to 5 shown, the present application discloses a lifting control system for a driverless mining truck. The lifting control system includes a mechanical displacement travel switch 10, a rear lidar 11, and a time counter 12.

[0050] Among them, the mechanical displacement travel switch 10 is arranged at the junction of the tail of the cargo box and the tail of the chassis. The mechanical displacement travel switch 10 is connected to the autonomous driving controller with a normally open state signal. The mechanical displacement travel switch 10 is used to trigger a high level when the lifting device 2 starts to work, and is also used to trigger a low level when the lifting device 2 descends in place. That is, when the mechanical displacement travel switch 10 triggers a low level, it means that the lifting device 2 has descended in place (i.e., the lowest point). Specifically, the mechanical displacement travel switch 10 will trigger a high-level signal to the autonomous driving controller, and the autonomous driving controller will then know that the cargo box starts to rise. When the cargo box descends in place, the mechanical displacement travel switch 10 triggers a low level. When the autonomous driving controller detects that the signal of the mechanical displacement travel switch 10 is reset, it will know that the cargo box has been seated in place.

[0051] The laser emission direction of the rear lidar 11 is horizontally backward, which is used to obtain the laser point cloud clustering projection area at the rear of the cargo box. Specifically, the laser point cloud clustering projection area is obtained through the laser point cloud ranging algorithm, and the laser point cloud clustering projection area is transmitted to the autonomous driving controller in real time. Since the laser emission direction of the rear lidar 11 is horizontally backward, the lidar is not easily blocked by dust and water vapor, reducing the probability of the lidar causing displacement detection failure and distortion of the cargo box.

[0052] The time counter 12 is used to obtain the time of the cargo box rising, staying at the highest point, and descending.

[0053] The autonomous driving controller is respectively connected to the mechanical displacement travel switch 10, the rear lidar 11, and the time counter 12 by signals. The autonomous driving controller can also obtain the engine speed in real time. The autonomous driving controller is used to obtain the starting rising state and the descending-in-place state of the cargo box through the mechanical displacement travel switch 10, and is also used to determine the highest point state of the cargo box and the holding time at the lifting highest point when the time of the time counter 12 is greater than or equal to the rising calibration duration, and the laser point cloud clustering projection area is close to the maximum projection area and / or the engine speed change rate exceeds the set threshold, and based on this, guide the lifting control system to rise, reach the highest point, stay at the highest point for a period of time, and descend, so as to achieve the purpose of reliably and safely controlling the lifting of the cargo box of the driverless mining vehicle.

[0054] The lifting control system of the present application is different from the prior art solution that uses laser ranging to perform real-time continuous monitoring of the cargo box lifting stroke in a closed-loop control. The present application uses an open-loop control of the lifting stroke and the lifting time, does not detect the lifting stroke in real time, and performs open-loop control. The autonomous driving controller is used to obtain the starting rising state and the descending-in-place state of the cargo box through the mechanical displacement travel switch 10, and is also used to confirm the highest point state of the cargo box and obtain the holding time at the lifting highest point by the time of the time counter 12 being greater than or equal to the rising calibration duration, combined with the laser point cloud clustering projection area and / or the engine speed change rate, and based on this, guide the lifting control system to control the starting rising state, the highest point state, staying at the highest point for a period of time, and the descending-in-place state of the cargo box, so as to achieve the purpose of reliably and safely controlling the lifting of the cargo box of the driverless mining vehicle. Compared with the prior art solution of continuous real-time monitoring in a closed-loop control, the lifting control system of the present application solves the technical problem of poor reliability of the lifting system of the driverless mining vehicle, and ignores the whole process and only focuses on important nodes, reducing the energy consumption of the lifting control system.

[0055] As Figure 4 shown, the laser point cloud acquisition diagrams of the laser point cloud signal in the rising stage (left figure) and the highest point state (right figure).

[0056] For the lifting control system of this application, only the mechanical displacement travel switch 10, rear lidar 11, and time counter 12 need to be added. Even the rear lidar 11 can use the lidar for positioning that comes with it. The structure is simple, the cost is low, and the reliability is high.

[0057] For the lifting control system of this application, the judgment of the highest point state during the rising stage of the cargo box lifting uses three features for redundant judgment, namely ① the laser point cloud clustering projection area of the rear lidar, ② the pre-calibrated engine speed change rate, and ③ the time of the pre-calibrated time counter. The three features are combined to judge the highest point state, which can reliably and accurately determine the highest point state of the cargo box. Compared with the existing technical solution that only relies on a forward lidar, it is more reliable and stable.

[0058] Regarding the highest point state, in one embodiment, the highest point state of the cargo box simultaneously satisfies that the time of the time counter 12 is greater than or equal to the rising calibration duration and the laser point cloud clustering projection area is close to the maximum projection area. Satisfying the two feature requirements simultaneously ensures the reliability of the highest point state. The rising calibration duration and the holding calibration duration are pre-calibrated according to the standard load of the cargo box obtained by the autonomous driving controller.

[0059] Regarding the highest point state, in one embodiment, the highest point state of the cargo box simultaneously satisfies that the time of the time counter 12 is greater than or equal to the rising calibration duration and the engine speed change rate exceeds the set threshold. Satisfying the two feature requirements simultaneously ensures the reliability of the highest point state. Specifically, the engine speed change rate refers to the change amount of the speed decreasing per second.

[0060] Regarding the highest point state, in one embodiment, the highest point state of the cargo box is determined by simultaneously satisfying that the time of the time counter 12 is greater than or equal to the rising calibration duration, the laser point cloud clustering projection area is close to the maximum projection area, and the engine speed change rate exceeds the set threshold. Satisfying the three feature requirements further ensures the reliability of the highest point state.

[0061] In one embodiment, a limit protection switch is set at the maximum stroke of the telescopic part of the lifting device. After the limit protection switch is triggered to work, the engine speed decreases. When the engine speed change rate exceeds the set threshold, it is determined as one of the conditions for the cargo box to reach the highest point state.

[0062] Specifically, when the telescopic part of the lifting device moves to the maximum stroke, the limit protection switch will be triggered. After the limit protection switch is triggered, the lifting device 2 will unload the hydraulic pressure. At this time, there will be an obvious fluctuation in the output torque of the gearbox, the hydraulic pressure value of the gearbox, and the engine speed. The engine speed will have an obvious change. Therefore, the autonomous driving controller monitors the change rate of the engine speed decrease. When the decrease rate n1 of the engine speed is greater than the set threshold, it indicates that the limit protection switch has been triggered, that is, the telescopic part of the lifting device has moved to the maximum stroke, that is, the highest point state reached by the cargo box.

[0063] In the lifting control system of this application, according to the working characteristics of the lifting device, when the lifting reaches the highest point, the limit protection switch will be triggered, and then the lifting hydraulic system will be unloaded, resulting in a decrease in the engine speed. Using the characteristic of the engine speed change rate as one of the characteristic judgments for the highest point of the lifting stroke, when the autonomous driving controller detects that the corresponding engine speed change rate exceeds the preset threshold and meets the characteristic requirements, the lifting control system will change the lifting control state from the lifting up request to the lifting hold request. Using the engine speed change rate characteristic as the characteristic judgment for the highest point of the lifting stroke is ingeniously designed and lays the foundation for the reliability of the lifting system.

[0064] In one embodiment, the laser point cloud clustering projection area is proportional to the lifting height of the cargo box. The autonomous driving controller obtains the laser point cloud clustering projection area Scur of the cargo box tail during unloading in real time through the rear lidar 11 and compares it with the laser point cloud clustering projection area Smax of the highest point of the cargo box calibrated in advance.

[0065] The laser point cloud clustering projection area is close to the maximum projection area, including:

[0066] |Smax - Scur| ≤ s1, where Scur is the laser point cloud clustering projection area of the cargo box tail obtained by the autonomous driving controller in real time through the rear lidar 11 during unloading, Smax is the laser point cloud clustering projection area of the highest point of the cargo box calibrated in advance, and s1 is the preset projection difference threshold.

[0067] For the lifting control system of this application, to ensure the detection safety and reliability at the highest point of the cargo box, a rear lidar is added to perform laser point cloud clustering detection on the tail of the cargo box. During the lifting process, the area of the laser point cloud clustering where the tail of the cargo box appears in the rear lidar is proportional to the lifting height of the cargo box. Whether the cargo box reaches the highest point is judged based on this feature. When the cargo box is lifted, when the cargo box is rising and approaching the highest point, it will appear within the detection range of the rear lidar. The rear lidar calculates the projected area of the laser point cloud on the tail of the cargo box during unloading. Since the lifting height of the cargo box is proportional to this area, the laser point cloud detection area in the state where the cargo box is lifted to the highest point is calculated in advance to obtain Smax. During the unloading process, the projected area of the laser point cloud on the tail of the cargo box is detected in real time as Scur. If |Smax - Scur| ≤ s1, it is considered that the cargo box meets one of the conditions for the highest point state.

[0068] Specifically, since there is no GPS positioning signal underground, the driverless mining truck needs to use lidar for real-time laser SLAM positioning. Lidars are installed at the front and rear ends of the underground mining truck for underground laser positioning purposes. Preferably, the rear lidar 11 directly uses the lidar at the rear end of the underground mining truck itself.

[0069] In one embodiment, the time corresponding to the time counter 12 during calibration includes the lifting calibration duration to reach the highest point and the holding calibration duration to stay at the highest point.

[0070] The lifting calibration duration time_up_crr = time_up + ((m1 - m) / m) * x_Time_up1;

[0071] Wherein, m is the standard load of the cargo box, time_up is the time to lift to the highest point when the cargo box has the standard load m, m1 is the cargo box load value of the driverless mining truck obtained by the automatic driving controller; x_Time_up1 is the lifting hold correction time coefficient obtained by looking up the table according to m1;

[0072] The holding calibration duration time_hold_crr = time_hold + ((m1 - m) / m) * x_Time_hold1;

[0073] Wherein, time_hold is the unloading time to stay at the highest point when the cargo box has the standard load m, and x_Time_hold1 is the lifting hold correction time coefficient obtained by looking up the table according to m1.

[0074] Specifically, the lifting time of the cargo box is related to the mass of the ore loaded in the cargo box. The cargo box load value m1 can obtain the current cargo box load value of the vehicle through the CAN bus to pre-calibrate the lifting revision time and the lifting hold revision time of the cargo box in advance. Specifically, a weight sensor can be set to obtain the actual cargo box load value.

[0075] Since the cargo box load value m1 is directly proportional to the lifting up time and the load unloading time, a lifting up correction time coefficient x_Time_up1 and a lifting hold correction time coefficient x_Time_hold1 are obtained by looking up the table according to m1 in advance.

[0076] For the standard load m of the cargo box, the time to lift to the highest point is time_up, and the time to stay at the highest point for unloading is time_hold. Then, after the vehicle is loaded in each driving cycle, the cargo box load value m1 during the vehicle operation is obtained.

[0077] The calibrated lifting duration time to reach the highest point time_up_crr = time_up + ((m1 - m) / m) * x_Time_up1; the calibrated holding duration time at the highest point time_hold_crr = time_hold_up + ((m1 - m) / m) * x_Time_hold1. During the lifting process, the time counter is accumulated by the automatic driving controller when the lifting device starts to work (the mechanical displacement travel switch 10 triggers a high level when the lifting device 2 starts to work). When the time counter reaches the value of time1 = time_up_crr, it is considered that the cargo box has reached the highest point currently, which meets one of the conditions for determining the highest point state of the cargo box. At this time, the lifting hold working condition is switched. When the time counter reaches time2 = time_up_crr + time_hold_crr, it is considered that the current lifting hold working condition ends, and the lifting down working condition is carried out.

[0078] Furthermore, the cargo box load value m1 is the actual cargo box load of the current vehicle obtained by the automatic driving controller through the CAN bus. Specifically, the cargo box load value of the vehicle can be obtained by various sensors and transmitted to the automatic driving controller through the CAN bus.

[0079] Specifically, the automatic driving controller obtains the time counter signal, the cargo box load signal, and the engine speed change signal through the CAN bus, and obtains the laser point cloud signal and the mechanical displacement travel switch related signal through the other signal lines.

[0080] In one embodiment, the engine speed change rate can also be replaced by the decreasing amplitude rate of the output torque of the transmission or the oil pressure of the transmission oil.

[0081] Specifically, when the telescopic part of the lifting device moves to the maximum stroke, the limit protection switch will be triggered. After the limit protection switch is triggered, the lifting device 2 performs oil pressure unloading. At this time, the gearbox output torque, the gearbox oil pressure value and the engine speed will have a significant downward fluctuation, and the engine speed will have a significant change. Therefore, the automatic driving controller can reflect that the telescopic part of the lifting device moves to the maximum stroke when the decline rate is greater than the corresponding threshold, that is, one of the conditions that the cargo box meets the highest point state.

[0082] like Figure 6 As shown, in a second aspect, the present application discloses a control method based on the above lifting control system, comprising the steps of:

[0083] The lifting device 2 starts to lift, and the mechanical displacement travel switch 10 triggers a high-level signal to the automatic driving controller, and the automatic driving controller learns that the cargo box starts to rise;

[0084] The cargo box rises until the time counter 12 is greater than or equal to the rise calibration time. Figure 6 At t1, and the laser point cloud clustering projection area is close to the maximum projection area and / or the engine speed change rate exceeds the set threshold, it is confirmed that the cargo box has reached the highest point;

[0085] The unloading is carried out by lifting and holding until the time of the time counter 12 is greater than or equal to the holding calibration time, and the cargo box starts to descend; wherein the lifting calibration time and the holding calibration time are obtained in advance according to the cargo box standard load calibration obtained by the automatic driving controller;

[0086] The machine moves down to the limit switch 10, triggering a low-level signal to the automatic driving controller, and the cargo box reaches the lowered position.

[0087] The control method of this application does not detect the lifting stroke in real time. It obtains the state that the cargo box starts to rise through the high level of the mechanical displacement travel switch 10, and confirms the state that the cargo box reaches the highest point through three redundant features, that is, the time of the time counter 12 is greater than or equal to the rising calibration duration, and the laser point cloud clustering projection area is close to the maximum projection area and / or the engine speed change rate exceeds the set threshold; it determines the holding duration at the highest point of the cargo box by the time of the time counter 12 being greater than or equal to the holding calibration duration; it confirms the state that the cargo box reaches the descending-in-place state by the mechanical displacement travel switch 10 triggering a low level, and controls the start-rising state, the reaching-the-highest-point state, the holding at the highest point for a period of time, and the descending-in-place state of the cargo box according to the guiding lifting control system, achieving the purpose of reliably and safely controlling the lifting of the cargo box of the driverless mining truck. Compared with the closed-loop control of continuous real-time monitoring in the prior art solution, the lifting control system of this application solves the technical problem of poor reliability of the lifting system of the driverless mining truck, and ignores the whole process and only grasps the important nodes, reducing the energy consumption of the lifting control system.

[0088] In one embodiment, the state of the highest point of the cargo box is confirmed according to the time of the time counter 12 being greater than or equal to the rising calibration duration and the laser point cloud clustering projection area being close to the maximum projection area;

[0089] Or, the state of the highest point of the cargo box is confirmed according to the time of the time counter 12 being greater than or equal to the rising calibration duration and the engine speed change rate exceeding the set threshold;

[0090] Or, the state of the highest point of the cargo box is determined by combining the time of the time counter 12 being greater than or equal to the rising calibration duration, the laser point cloud clustering projection area being close to the maximum projection area, and the engine speed change rate exceeding the set threshold.

[0091] In one embodiment, a limit protection switch is set at the maximum stroke of the telescopic part of the lifting device. After the limit protection switch is triggered to work, the engine speed decreases. When the engine speed change rate exceeds the set threshold, it is determined as one of the conditions for the cargo box to reach the highest point state.

[0092] Specifically, when the telescopic part of the lifting device moves to the maximum stroke, the limit protection switch will be triggered; after the limit protection switch is triggered to work, the lifting device 2 performs oil pressure unloading. At this time, there will be an obvious fluctuation in the output torque of the gearbox, the oil pressure value of the gearbox, and the engine speed, and there will be an obvious change in the engine speed. Therefore, the autonomous driving controller monitors the decrease change rate of the engine speed. When the decrease rate n1 of the engine speed is greater than the set threshold, that is, the telescopic part of the lifting device moves to the maximum stroke, which is one of the conditions for the cargo box to reach the highest point state.

[0093] The control method of the present application, according to the working characteristics of the lifting device, will trigger the limit protection switch when the lifting reaches the highest point, thereby triggering the lifting hydraulic system to unload the load, thereby causing the engine speed to drop. The characteristics of the engine speed change rate are used as one of the characteristic judgments of the highest point of the lifting stroke. The automatic driving controller detects that the corresponding engine speed change rate meets the characteristic requirements when it exceeds a preset threshold. Thereafter, the lifting control system will change the lifting control state from a lifting rise request to a lifting hold request, and use the engine speed change rate characteristics as the characteristic judgment of the highest point of the lifting stroke. The design is ingenious and lays the foundation for the reliability of the lifting system.

[0094] In one embodiment, the laser point cloud cluster projection area is proportional to the lifting height of the cargo box. The automatic driving controller obtains the laser point cloud cluster projection area Scur of the tail of the cargo box during unloading in real time through the rear-facing laser radar 11, and compares it with the laser point cloud cluster projection area Smax of the highest point of the cargo box calibrated in advance.

[0095] The laser point cloud clustering projection area is close to the maximum projection area, including:

[0096] |Smax-Scur|≤s1, where Scur is the laser point cloud cluster projection area of the tail of the cargo box during unloading, which is obtained in real time by the autonomous driving controller through the rear-facing laser radar 11, Smax is the laser point cloud cluster projection area of the highest point of the cargo box calibrated in advance, and s1 is the projection difference threshold set in advance.

[0097] The control method of the present application, in order to ensure the safety and reliability of the detection of the cargo box at the highest point, adds a backward laser radar to perform laser point cloud clustering detection on the tail of the cargo box. During the lifting process, the laser point cloud clustering area of the tail of the cargo box that appears in the backward laser radar is proportional to the lifting height of the cargo box. This feature is used to determine whether the cargo box has reached the highest point. When the cargo box is lifted, when the cargo box approaches the highest point during the rising process, it will appear in the detection range of the backward laser radar. The rear end of the cargo box is clustered by the backward laser radar to calculate the projection area when the cargo box is unloaded. Because the lifting height of the cargo box is proportional to this area, the laser point cloud detection area of the cargo box lifted to the highest point is calculated in advance to obtain Smax. During the unloading process, the real-time detection of the laser point cloud projection area of the tail of the cargo box is Scur, |Smax-Scur|≤s1, then it is considered that the cargo box has reached one of the highest point state conditions at this time.

[0098] Specifically, since there is no GPS positioning signal underground, the unmanned mine car needs to use laser radar for laser SLAM real-time positioning, and the front and rear ends of the underground mine car will be installed with laser radar for underground laser positioning purposes. Preferably, the rear laser radar 11 directly uses the rear end laser radar of the underground mine car.

[0099] In one embodiment, the time corresponding to the time counter 12 during calibration includes the lifting calibration duration to reach the highest point and the holding calibration duration to stay at the highest point.

[0100] The lifting calibration duration time_up_crr = time_up + ((m1 - m) / m) * x_Time_up1;

[0101] where m is the standard load of the cargo box, time_up is the time to lift to the highest point when the cargo box has the standard load m, m1 is the cargo box load value of the driverless mining truck obtained by the autonomous driving controller; x_Time_up1 is the lifting and holding correction time coefficient obtained by looking up the table according to m1.

[0102] The holding calibration duration time_hold_crr = time_hold + ((m1 - m) / m) * x_Time_hold1;

[0103] where time_hold is the unloading time to stay at the highest point when the cargo box has the standard load m, and x_Time_hold1 is the lifting and holding correction time coefficient obtained by looking up the table according to m1.

[0104] Specifically, the time for the cargo box to lift is related to the mass of the ore loaded in the cargo box. The cargo box load estimate m1 can obtain the actual cargo box load of the current vehicle through the CAN bus to pre-calibrate the revised time for the cargo box to lift and the revised time for lifting and holding in advance.

[0105] Since the load mass m1 is proportional to the lifting time and the load unloading time, a lifting-up correction time coefficient x_Time_up1 and a lifting and holding correction time coefficient x_Time_hold1 are obtained by looking up the table according to m1 in advance.

[0106] With the standard load m of the cargo box, the time to lift to the highest point is time_up, and the unloading time to stay at the highest point is time_hold. Then, after the vehicle is loaded in each driving cycle, the cargo box load value m1 is obtained during the vehicle operation.

[0107] The lifting calibration duration time_up_crr to reach the highest point is time_up_crr = time_up + ((m1 - m) / m) * x_Time_up1; the holding calibration duration time_hold_crr at the highest point is time_hold_crr = time_hold_up + ((m1 - m) / m) * x_Time_hold1. During the lifting process, the time counter is accumulated by the autonomous driving controller when the lifting device starts to work (the mechanical displacement travel switch 10 triggers a high level when the lifting device 2 starts to work). When the time counter reaches the value of time1 = time_up_crr, it is considered that the cargo box has reached the highest point in the current lift, meeting one of the conditions for determining the highest point state of the cargo box. At this time, the lift-holding working condition is switched. When the time counter reaches time2 = time_up_crr + time_hold_crr, it is considered that the current lift-holding working condition ends, and the lift-lowering working condition is carried out.

[0108] Furthermore, the cargo box load value m1 is the actual cargo box load of the current vehicle obtained by the autonomous driving controller through the CAN bus. Specifically, the cargo box load value of the vehicle can be obtained by various sensors and transmitted to the autonomous driving controller through the CAN bus.

[0109] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application. Unless otherwise clearly specified and defined, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0110] It should be noted that in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0111] The above are only specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A lifting control system for an unmanned mining vehicle, characterized in that, Comprising: A mechanical displacement travel switch (10) which is arranged at the junction of the rear of the cargo box and the rear of the chassis and is connected to the automatic driving controller in a normally open state; the mechanical displacement travel switch (10) is used to trigger a high level when the lifting device (2) starts to work and is also used to trigger a low level when the lifting device (2) descends in place; A rear lidar (11) whose laser emission direction is horizontally backward and is used to obtain the laser point cloud clustering projection area of the rear of the cargo box; A time counter (12) which is used to obtain the time of the cargo box rising, staying at the highest point, and descending; The automatic driving controller is respectively signal-connected to the rear lidar (11) and the time counter (12). The automatic driving controller is used to obtain the starting rising state and descending in place state of the cargo box through the mechanical displacement travel switch (10), and is also used to determine the highest point state of the cargo box and obtain the holding calibration duration of the highest point of the cargo box when the time of the time counter (12) is greater than or equal to the corresponding calibrated duration, and the laser point cloud clustering projection area is close to the maximum projection area and / or the engine speed change rate exceeds the set threshold.

2. The lifting control system of an unmanned mining vehicle according to claim 1, wherein: The highest point state of the cargo box simultaneously satisfies that the time of the time counter (12) is greater than or equal to the rising calibration duration and the laser point cloud clustering projection area is close to the maximum projection area; the rising calibration duration and the holding calibration duration are calibrated in advance according to the standard load of the cargo box obtained by the automatic driving controller.

3. The lifting control system of an unmanned mining vehicle according to claim 1, characterized in that: The highest point state of the cargo box simultaneously satisfies that the time of the time counter (12) is greater than or equal to the rising calibration duration and the engine speed change rate exceeds the set threshold.

4. The lifting control system of an unmanned mining vehicle according to claim 1, characterized in that: The highest point state of the cargo box is determined by combining that the time of the time counter (12) is greater than or equal to the rising calibration duration, the laser point cloud clustering projection area is close to the maximum projection area, and the engine speed change rate exceeds the set threshold.

5. The lifting control system of an unmanned mining vehicle according to claim 1, characterized in that: A limit protection switch is arranged at the maximum stroke of the telescopic part of the lifting device. After the limit protection switch is triggered to work, the engine speed decreases. When the engine speed change rate exceeds the set threshold, it is determined as one of the conditions for the cargo box to reach the highest point state.

6. The lifting control system of an unmanned mining truck according to claim 1, characterized in that: The laser point cloud clustering projection area is proportional to the lifting height of the cargo box. The laser point cloud clustering projection area being close to the maximum projection area includes: |Smax - Scur| ≤ s1, where Scur is the laser point cloud clustering projection area of the rear of the cargo box obtained by the automatic driving controller through the rear lidar (11) in real time during unloading, Smax is the laser point cloud clustering projection area of the highest point of the cargo box calibrated in advance, and s1 is the projection difference threshold set in advance.

7. The lifting control system of an unmanned mining vehicle according to claim 1, characterized in that: The time of the time counter (12) corresponding to the calibrated duration includes the lifting calibration duration time_up_crr to reach the highest point and the holding calibration duration time_hold_crr to stay at the highest point; time_up_crr = time_up + ((m1 - m) / m) * x_Time_up1; Among them, m is the standard load of the cargo box, time_up is the time for the cargo box to be lifted to the highest point when the standard load is m, m1 is the cargo box load value of the unmanned mining car obtained by the automatic driving controller; x_Time_up1 is the lifting and rising correction time coefficient obtained by looking up the table according to m1; time_hold_crr=time_hold+((m1-m) / m)*x_Time_hold1; Among them, time_hold is the unloading time that the cargo box maintains at the highest point when the standard load is m, and x_Time_hold1 is the lifting holding correction time coefficient obtained by looking up the table based on m1.

8. The lifting control system of an unmanned mining vehicle according to claim 1, characterized in that: The engine speed change rate may also be replaced by the numerical decrease rate of the variable speed box output torque or the transmission oil pressure.

9. A control method for the lifting control system according to claim 1, characterized in that, Contains steps: The lifting device (2) starts lifting, and the mechanical displacement travel switch (10) triggers a high-level signal to the automatic driving controller, and the automatic driving controller learns that the cargo box starts to rise; The cargo box rises until the time of the time counter (12) is greater than or equal to the rising calibration time, and the laser point cloud cluster projection area is close to the maximum projection area and / or the engine speed change rate exceeds the set threshold, confirming that the cargo box has reached the highest point; The unloading is performed by lifting and holding until the time of the time counter (12) is greater than or equal to the holding calibration time, and the cargo box starts to descend; wherein the lifting calibration time and the holding calibration time are obtained in advance according to the cargo box standard load calibration obtained by the automatic driving controller; The container descends until the mechanical displacement travel switch (10) triggers a low-level signal to the automatic driving controller, and the container reaches the descending position.

10. The control method of the lifting control system according to claim 9, characterized in that: The highest point state of the cargo box is confirmed based on the time of the time counter (12) being greater than or equal to the ascending calibration time and the laser point cloud clustering projection area being close to the maximum projection area; Alternatively, the highest point state of the cargo box is confirmed based on the time of the time counter (12) being greater than or equal to the rising calibration time and the engine speed change rate exceeding a set threshold value; Alternatively, the highest point state of the cargo box is determined based on the time of the time counter (12) being greater than or equal to the rising calibration time, the laser point cloud clustering projection area being close to the maximum projection area, and the engine speed change rate exceeding a set threshold.

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