Gear shifting process control method and system for electric drive transmission of engineering machinery

Abstract

Disclosed in the present invention are a gear shifting process control method and system for an electric drive transmission of engineering machinery. The method comprises: in response to having received a gear-shifting signal, acquiring a required gear, a current gear, an electric-motor output torque and a slope signal; on the basis of the electric-motor output torque and the slope signal, determining a gear-shifting load type, and on the basis of the required gear and the current gear, determining a gear-shifting requirement type; if the gear-shifting load type is light- and medium-load gear shifting and the gear-shifting requirement type is an upshift requirement, sending an instruction to execute light- and medium-load upshift control; and if the gear-shifting load type is the light- and medium-load gear shifting and the gear-shifting requirement type is a downshift requirement, sending an instruction to execute light- and medium-load downshift control. During light- and medium-load upshift control or light- and medium-load downshift control, rotation speeds on a pre-clutch side and a post-clutch side are rapidly synchronized, thereby reducing the sliding friction work of a clutch and shortening a gear-shifting time.

Description

A control method and system for gear shifting process of electric drive gearbox of engineering machinery TECHNICAL FIELD

[0001] The present application belongs to the technical field of engineering machinery, and relates to a control method and system for gear shifting process of electric drive gearbox of engineering machinery. BACKGROUND

[0002] Electric drive of engineering machinery is increasingly developing, and a traditional power transmission route of engine + power shift gearbox is replaced by a route represented by motor + power shift gearbox (hereinafter referred to as electric drive gearbox). Since the speed and torque coverage range of the motor is wider, the number of gears of the electric drive gearbox can be greatly reduced compared with the traditional gearbox, thus causing the speed ratio step difference between the gears of the gearbox to be significantly increased. Meanwhile, due to the difference between the characteristics of the motor and the engine, the cancellation of the hydraulic torque converter in the gearbox, and other reasons, the smoothness of the gear shifting process of the electric drive gearbox is more difficult to control, the driving experience is poor, and the development of electric drive of the engineering machinery industry is seriously restricted.

[0003] The prior art has the following defects:

[0004] The existing patent reduces the torque of the motor during the gear shifting process, which is beneficial to the speed synchronization of the motor after the clutch is filled with oil and drags the motor, but for the downshift condition, reducing the torque of the motor is not conducive to the speed rise of the motor (the motor should rise in speed during downshift), thus making the speed synchronization more difficult and affecting the smoothness of gear shifting.

[0005] The existing document changes the working mode of the motor during the gear shifting process to speed up the motor and realize the speed synchronization of the master and slave friction plates. This technology is a commonly used gear shifting speed regulation method for AMT vehicles, and the gear shifting process control is complex. Moreover, the working condition of engineering machinery and the load change are severe. If the load suddenly increases during the speed regulation process, a strong power interruption will be generated, and the speed may not be synchronized.

[0006] SUMMARY

[0007] In view of at least one of the above technical problems, the present application provides a control method and system for gear shifting process of electric drive gearbox of engineering machinery.

[0008] TECHNICAL SOLUTION

[0009] In a first aspect, a control method for gear shifting process of electric drive gearbox of engineering machinery is provided, comprising:

[0010] In response to receiving a gear shifting signal, obtaining a required gear, a current gear, a motor output torque, and a slope signal;

[0011] determining a shift load type according to the motor output torque and the slope signal, wherein the shift load type comprises a small-medium load shift and a large load shift;

[0012] determining a shift demand type according to the demand gear and the current gear, wherein the shift demand type is an upshift demand or a downshift demand;

[0013] if the shift load type is a small-medium load shift and the shift demand type is an upshift demand, issuing an instruction to execute a small-medium load upshift control;

[0014] if the shift load type is a small-medium load shift and the shift demand type is a downshift demand, issuing an instruction to execute a small-medium load downshift control.

[0015] In some embodiments, determining a shift load type according to the motor output torque and the slope signal comprises:

[0016] if the motor output torque is less than a large load shift preset condition and the slope signal is less than a large slope shift preset condition, the shift load type is a small-medium load shift;

[0017] if the motor output torque is not less than the large load shift preset condition and the slope signal is not less than the large slope shift preset condition, the shift load type is a large load shift.

[0018] In some embodiments, determining a shift demand type according to the demand gear and the current gear comprises:

[0019] if the demand gear > the current gear, the shift demand type is an upshift demand;

[0020] if the demand gear < the current gear, the shift demand type is a downshift demand.

[0021] In some embodiments, before executing the small-medium load upshift control or the small-medium load downshift control, further comprising judging a to-be-disengaged clutch and a to-be-engaged clutch participating in the shift, specifically comprising:

[0022] the to-be-disengaged clutch: a clutch corresponding to the current gear and excluding a clutch simultaneously included by the clutch corresponding to the current gear and a clutch corresponding to the demand gear;

[0023] the to-be-engaged clutch: a clutch corresponding to the demand gear and excluding a clutch simultaneously included by the clutch corresponding to the current gear and the clutch corresponding to the demand gear.

[0024] In some embodiments, the small-medium load upshift control comprises:

[0025] decrease the oil pressure of the to-be-separated clutch at a first slope value, and maintain the to-be-engaged clutch at a first set oil pressure value after pre-filling oil, wherein the first set oil pressure value represents a set range value below the clutch half-engaged oil pressure;

[0026] in response to the to-be-separated clutch oil pressure decreasing to 0 and the to-be-engaged clutch oil pressure being maintained at the first set oil pressure value, control the drive motor output torque to decrease to a first torque set value;

[0027] in response to the master-slave rotational speed difference of the to-be-engaged clutch being less than a first rotational speed difference set value, control the to-be-engaged clutch oil pressure to increase to a target oil pressure value within a first time period, and control the drive motor output torque to increase to a whole-machine requested motor torque value within a second time period, and the gear shifting is completed.

[0028] In some embodiments, the first torque set value is determined according to the master-slave rotational speed difference of the to-be-engaged clutch before gear shifting and the drive motor output torque.

[0029] In some embodiments, the small-medium load downshift control comprises:

[0030] decrease the oil pressure of the to-be-separated clutch at a first slope value, and maintain the to-be-engaged clutch at a second set oil pressure value after pre-filling oil, wherein the second set oil pressure value represents a set range value below the clutch half-engaged oil pressure;

[0031] in response to the to-be-separated clutch oil pressure decreasing to 0 and the to-be-engaged clutch oil pressure being maintained at the first set oil pressure value, control the drive motor output torque to increase to a second torque set value;

[0032] in response to the master-slave rotational speed difference of the to-be-engaged clutch being less than a second rotational speed difference set value, control the to-be-engaged clutch oil pressure to increase to a target oil pressure value within a first time period, and control the drive motor output torque to decrease to a whole-machine requested motor torque value within a second time period, and the gear shifting is completed.

[0033] In some embodiments, the second torque set value is determined according to the master-slave rotational speed difference of the to-be-engaged clutch before gear shifting and the drive motor output torque.

[0034] In some embodiments, the above-mentioned construction machinery electric drive gearbox gear shifting process control method satisfies at least one of the following:

[0035] the first slope value is the oil pressure decrease rate when the oil inlet channel of the to-be-separated clutch is completely closed and the oil return channel is completely opened;

[0036] the to-be-engaged clutch oil pressure increasing to the target oil pressure value within the first time period represents that the oil return channel of the to-be-engaged clutch is completely closed and the oil inlet channel is completely opened, and the oil is filled to the maximum oil pressure of the to-be-engaged clutch;

[0037] The second time period is determined by the difference between the actual torque value of the driving motor and the requested motor torque value of the whole machine;

[0038] The requested motor torque value of the whole machine is determined according to the driving motor speed and the accelerator pedal opening degree.

[0039] In some embodiments, during the execution of the small-medium load upshift control or small-medium load downshift control process, if the drop rate of the gearbox output shaft speed is greater than the set rate value, the small-medium load upshift control or small-medium load downshift control is exited, and the second slope value is used to increase the oil pressure of the coupling to be combined to the target oil pressure value.

[0040] In some embodiments, the second slope value is obtained by the gearbox output shaft speed change slope and the driving motor torque.

[0041] In a second aspect, an engineering machinery electric drive gearbox shifting process control device is provided, comprising a memory and a processor, the memory is used to store instructions, the instructions are used to control the processor to operate to execute the engineering machinery electric drive gearbox shifting process control method according to the first aspect.

[0042] In a third aspect, an engineering machinery electric drive gearbox shifting process control system is provided, comprising the engineering machinery electric drive gearbox shifting process control device according to the second aspect.

[0043] In a fourth aspect, an engineering machinery is provided, comprising the engineering machinery electric drive gearbox shifting process control device according to the first aspect or the engineering machinery electric drive gearbox shifting process control system according to the second aspect.

[0044] Beneficial effects: the engineering machinery electric drive gearbox shifting process control method and system provided by the application can quickly synchronize the front and rear speeds of the clutch, reduce the sliding friction work of the clutch, and are more suitable for the application requirements of the variable load of the engineering machinery, effectively shorten the shifting time, and solve the problem of uneven shifting caused by improper clutch oil pressure control during the shifting synchronization process. BRIEF DESCRIPTION OF DRAWINGS

[0045] Fig. 1 is a schematic diagram of the engineering machinery electric drive gearbox shifting process control system according to an embodiment of the application;

[0046] Fig. 2 is a main flowchart of the engineering machinery electric drive gearbox shifting process control method according to an embodiment of the application;

[0047] Fig. 3 is a flowchart of the small-medium load upshift control according to an embodiment of the application;

[0048] Fig. 4 is a diagram showing the parameter changes during the small-medium load upshift control process according to an embodiment of the application;

[0049] Fig. 5 is a flowchart of the small and medium load downshift control of the embodiment of the application;

[0050] Fig. 6 is a schematic diagram of the method for determining the motor torque value requested by the whole machine in the embodiment of the application;

[0051] Fig. 7 is a schematic diagram of the torque exchange stage in the large load shift process in the embodiment of the application. DETAILED DESCRIPTION

[0052] The application will be further described below in conjunction with the drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0053] In the description of the application, the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, etc. are understood as not including the number, above, below, within, etc. are understood as including the number. If it is described as first, second, it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0054] In the description of the application, the description of the reference terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0055] Embodiment 1: In a first aspect, the embodiment provides a control method for shift process of an electric drive gearbox of a construction machine, comprising:

[0056] Step S1, in response to receiving a shift signal, obtaining a required gear Gear Req , a current gear Gear Curr , a motor output torque T Motor and a slope signal a;

[0057] Step S2, determining the shift load type according to the motor output torque T Motor and the slope signal a, wherein the shift load type includes small and medium load shift and large load shift;

[0058] In some embodiments, determining the shift load type according to the motor output torque and the slope signal comprises:

[0059] if the motor output torque T Motor is less than a large load shift preset condition T t and the slope signal a is less than a large slope shift preset condition a t , the shift load type is a small load shift.

[0060] if the motor output torque T Motor is less than a large load shift preset condition T t and the slope signal a is less than a large slope shift preset condition a t , the shift load type is a large load shift.

[0061] Step S3, determining a shift demand type according to the demand gear Gear Req and the current gear Gear Curr , wherein the shift demand type is an upshift demand or a downshift demand.

[0062] In some embodiments, determining the shift demand type according to the demand gear Gear Req and the current gear Gear Curr includes:

[0063] if the demand gear Gear Req > the current gear Gear Curr , the shift demand type is an upshift demand.

[0064] if the demand gear Gear Req < the current gear Gear Curr , the shift demand type is a downshift demand.

[0065] Step S4, if the shift load type is a small load shift and the shift demand type is an upshift demand, issuing an instruction to execute a small load upshift control; if the shift load type is a small load shift and the shift demand type is a downshift demand, issuing an instruction to execute a small load downshift control.

[0066] In some embodiments, before executing the small load upshift control or the small load downshift control, further including judging a to-be-disengaged clutch and a to-be-engaged clutch involved in the shift, specifically including:

[0067] the to-be-disengaged clutch: a clutch corresponding to the current gear and excluding a clutch simultaneously included by the clutch corresponding to the current gear and the clutch corresponding to the demand gear;

[0068] the to-be-engaged clutch: a clutch corresponding to the demand gear and excluding a clutch simultaneously included by the clutch corresponding to the current gear and the clutch corresponding to the demand gear.

[0069] In some embodiments, the small load upshift control includes:

[0070] decreasing the oil pressure of the to-be-disengaged clutch at a first slope value, and maintaining the to-be-engaged clutch at a first set oil pressure value after pre-filling oil, wherein the first set oil pressure value represents a set range value below the clutch half-engagement oil pressure;

[0071] in response to the oil pressure of the to-be-disengaged clutch decreasing to 0 and the oil pressure of the to-be-engaged clutch being maintained at the first set oil pressure value, controlling the output torque of the driving motor to decrease to a first torque set value T1;

[0072] in response to the difference between the driving speed and the driven speed of the to-be-engaged clutch being less than a first speed difference set value Dn1, controlling the oil pressure of the to-be-engaged clutch to increase to a target oil pressure value within a first time period, and controlling the output torque of the driving motor to increase to a whole-machine requested motor torque value within a second time period, and the gear shifting being completed.

[0073] wherein the first torque set value T1 is determined according to the difference between the driving speed and the driven speed of the to-be-engaged clutch before the gear shifting and the output torque of the driving motor.

[0074] In some embodiments, the small-medium load downshift control comprises:

[0075] decreasing the oil pressure of the to-be-disengaged clutch at a first slope value, and maintaining the to-be-engaged clutch at a second set oil pressure value after pre-filling oil, wherein the second set oil pressure value represents a set range value below the clutch half-engagement oil pressure;

[0076] in response to the oil pressure of the to-be-disengaged clutch decreasing to 0 and the oil pressure of the to-be-engaged clutch being maintained at the first set oil pressure value, controlling the output torque of the driving motor to increase to a second torque set value T2;

[0077] in response to the difference between the driving speed and the driven speed of the to-be-engaged clutch being less than a second speed difference set value Dn2, controlling the oil pressure of the to-be-engaged clutch to increase to a target oil pressure value within a first time period, and controlling the output torque of the driving motor to decrease to a whole-machine requested motor torque value within a second time period, and the gear shifting being completed.

[0078] wherein the second torque set value T2 is determined according to the difference between the driving speed and the driven speed of the to-be-engaged clutch before the gear shifting and the output torque of the driving motor.

[0079] In some embodiments, in the small-medium load upshift control or the small-medium load downshift control:

[0080] the first slope value is the oil pressure decreasing rate when the oil inlet passage of the to-be-disengaged clutch is completely closed and the oil return passage is completely opened;

[0081] the oil pressure of the to-be-engaged clutch increasing to the target oil pressure value within the first time period means that the oil return passage of the to-be-engaged clutch is completely closed and the oil inlet passage is completely opened, and the oil is filled to the maximum oil pressure of the to-be-engaged clutch.

[0082] The second time period is determined by the difference between the actual motor torque value and the whole machine requested motor torque value.

[0083] The whole machine requested motor torque value is determined according to the driving motor speed and the accelerator pedal opening degree.

[0084] It should be particularly noted that, in the process of executing the small load upshift control or the small load downshift control, if the gearbox output shaft speed decreases at a rate greater than the set rate value Δv, the small load upshift control or the small load downshift control is exited, and the second slope value is used to increase the oil pressure of the coupling clutch to the target oil pressure value, so as to quickly restore the power transmission.

[0085] The second slope value is obtained by the gearbox output shaft speed change slope and the driving motor torque.

[0086] Embodiment 2: In a second aspect, the embodiment provides an engineering machinery electric drive gearbox shifting process control device, comprising a memory and a processor, the memory is used to store instructions, the instructions are used to control the processor to operate, so as to execute the engineering machinery electric drive gearbox shifting process control method according to the first aspect.

[0087] In some embodiments, the engineering machinery electric drive gearbox shifting process control device is a gearbox control unit as shown in FIG. 1.

[0088] Embodiment 3: In a third aspect, the embodiment provides an engineering machinery electric drive gearbox shifting process control system, comprising the engineering machinery electric drive gearbox shifting process control device according to the second aspect.

[0089] In some embodiments, as shown in FIG. 1, an engineering machinery electric drive gearbox shifting process control system comprises a shifting handle, a gearbox control unit, a motor control unit, a whole machine control unit, a solenoid valve, a speed sensor, and a slope sensor.

[0090] The shifting handle is used to switch the gearbox gear position.

[0091] The solenoid valve is used to control the coupling and separation oil pressure of the clutch.

[0092] The speed sensor is used to collect the gearbox output shaft speed.

[0093] The slope sensor is used to collect the vehicle inclination angle and determine the vehicle driving road surface type.

[0094] The gearbox control unit is used for collecting the rotating speed sensor signal to obtain the rotating speed state of the gearbox, and controlling the electromagnetic valve according to the shift request to realize the clutch oil pressure control in the shift process, and overruling the motor output torque and rotating speed in the shift process according to the shift demand.

[0095] The motor control unit is used for receiving the control mode and rotating speed, torque request of the whole machine control unit and the gearbox control unit, and responding to the corresponding demand.

[0096] The whole machine control unit is used for collecting the shift handle operation signal, judging whether the shift is allowed, and sending the gear request signal to the gearbox control unit, analyzing the driver rotating speed and torque request, and sending to the motor control unit to realize the motor control.

[0097] The gearbox shift process control flow of one embodiment of the present application is shown in Fig. 2, and the specific steps are as follows:

[0098] The shift handle gear change request, motor output torque and road slope are monitored in real time. When the demand gear changes, the following conditions are judged:

[0099] The demand gear Gear Req and the current gear Gear Curr are judged: if Gear Req >Gear Curr , the gearbox is an upshift demand; if Gear Req <Gear Curr , the gearbox is a downshift demand.

[0100] The clutch participating in the shift is judged, the clutch corresponding to the current gear is the to-be-separated clutch, the clutch corresponding to the demand gear is the to-be-combined clutch, and if the current gear and the demand gear contain a clutch at the same time, the clutch can not participate in the separation and combination in the shift process according to the clutch control strategy.

[0101] The gearbox shift type is judged according to the motor output torque T Motor and the slope signal a: if T Motor is less than the large load shift preset condition T t and a is less than the large slope shift preset condition a t , the shift type is a small and medium load shift; otherwise, it is a large load shift.

[0102] (1) When the shift type is judged to be a small and medium load upshift, the small and medium load upshift process control of one embodiment of the present application is shown in Figs. 3 and 4, and the shift process control steps are as follows:

[0103] (1-1) The to-be-separated clutch is controlled to reduce the oil pressure to 0 bar at a first slope value to complete the gear disengagement;

[0104] (1-2) After the pre-priming of the to-be-engaged clutch, the oil pressure is kept below the half-engagement point to prevent the clutch from slipping in advance and causing speed fluctuation;

[0105] (1-3) The gearbox control unit requests the motor to output a negative torque T1 to control the motor speed to decrease, so that the speed difference between the driving and driven ends of the to-be-engaged clutch gradually decreases;

[0106] (1-4) When the speed difference is less than Dn1, the oil pressure of the to-be-engaged clutch is controlled to rise to the target oil pressure within a first time period;

[0107] (1-5) The gearbox control unit controls the motor torque to recover to the whole-machine requested motor torque value within a second time period, and exits the overreach control, completing the gear shifting.

[0108] (2) When the gear shifting type is determined to be a small-medium load downshift, the small-medium load downshift process control of one embodiment of the application is shown in FIG. 5, and the gear shifting process control steps are as follows:

[0109] (2-1) The oil pressure of the to-be-disengaged clutch is controlled to decrease to 0 bar at a first slope value, completing the gear disengagement;

[0110] (2-2) After the pre-priming of the to-be-engaged clutch, the oil pressure is kept below the half-engagement point to prevent the clutch from slipping in advance and causing speed fluctuation;

[0111] (2-3) The gearbox control unit requests the motor to output a positive torque T2 to control the motor speed to increase, so that the speed difference between the driving and driven ends of the to-be-engaged clutch gradually decreases;

[0112] (2-4) When the speed difference is less than Dn2, the oil pressure of the to-be-engaged clutch is controlled to rise to the target oil pressure within a first time period;

[0113] (2-5) The gearbox control unit controls the motor torque to recover to the whole-machine requested motor torque value within a second time period, and exits the overreach control, completing the gear shifting.

[0114] As shown in FIG. 6, the above-mentioned whole-machine requested motor torque value is determined according to the driving motor speed and the accelerator pedal opening degree.

[0115] In particular, if the speed decrease rate of the gearbox output shaft is greater than Δv during the small-medium load upshift or downshift process, it is determined that the operating condition of the whole machine has changed suddenly, the to-be-engaged clutch no longer maintains the oil pressure below the half engagement, but increases the oil pressure of the to-be-engaged clutch to the target oil pressure at a second slope value, quickly recovering the power transmission.

[0116] (3) When the shift type is judged as large load upshift or large load downshift, in order to make the whole machine not appear power interruption, as shown in FIG. 7, the oil pressure curves of the to-be-disengaged clutch and the to-be-engaged clutch need to be controlled to have a certain degree of intersection, so as to realize torque exchange, ensure that the power is not interrupted during the shift process, and the shift process oil pressure control strategy is consistent with the traditional engine-driven gearbox shift, and the application will not be described again.

[0117] The system and method described above reduce the clutch sliding friction work during the shift process of the electrically-driven gearbox, shorten the shift time, and solve the shift roughness problem caused by improper clutch oil pressure control during the shift synchronization process of the electrically-driven gearbox.

[0118] In a fourth aspect, an engineering machine is provided, comprising the engineering machine electrically-driven gearbox shift process control device or the engineering machine electrically-driven gearbox shift process control system described above.

[0119] The application is described with reference to flowcharts and / or block diagrams according to the methods, devices (systems), and computer program products of the embodiments of the application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices produce a device for implementing the functions specified in one or more flows in the flowcharts and / or one or more blocks in the block diagrams.

[0120] These computer program instructions can also be stored in a computer readable memory that can guide the computer or other programmable data processing devices to work in a specific way, so that the instructions stored in the computer readable memory produce a product including instruction devices, which implement the functions specified in one or more flows in the flowcharts and / or one or more blocks in the block diagrams.

[0121] These computer program instructions can also be loaded into a computer or other programmable data processing device, so that a series of operation steps are performed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more flows in the flowcharts and / or one or more blocks in the block diagrams.

[0122] The above merely describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. A method of controlling a shift process of an electrically driven transmission of a working machine, characterized by, The method comprises the following steps: in response to receiving the shift signal, obtaining a required gear, a current gear, a motor output torque and a slope signal; determining a shift load type according to the motor output torque and the slope signal, wherein the shift load type comprises a small-medium load shift and a large load shift; determining a shift demand type according to the required gear and the current gear, wherein the shift demand type is an upshift demand or a downshift demand; if the shift load type is a small-medium load shift and the shift demand type is an upshift demand, issuing an instruction to execute a small-medium load upshift control; if the shift load type is a small-medium load shift and the shift demand type is a downshift demand, issuing an instruction to execute a small-medium load downshift control.

2. The control method of claim 1, wherein, The method for determining the shift load type according to the motor output torque and the slope signal comprises the following steps: if the motor output torque is less than a large load shift preset condition and the slope signal is less than a large slope shift preset condition, the shift load type is a small-medium load shift; if the motor output torque is not less than the large load shift preset condition and the slope signal is not less than the large slope shift preset condition, the shift load type is a large load shift.

3. A control method of a power shift transmission of a working machine according to claim 1 or 2, characterized in that, The method for determining the shift demand type according to the required gear and the current gear comprises the following steps: if the required gear is greater than the current gear, the shift demand type is an upshift demand; if the required gear is less than the current gear, the shift demand type is a downshift demand.

4. The control method of claim 1, wherein, Before executing the small-medium load upshift control or the small-medium load downshift control, the method further comprises judging a to-be-separated clutch and a to-be-engaged clutch involved in the shift, and specifically comprises the following steps: the to-be-separated clutch: a clutch corresponding to the current gear and excluding a clutch simultaneously contained by the clutch corresponding to the current gear and a clutch corresponding to the required gear; the to-be-engaged clutch: a clutch corresponding to the required gear and excluding a clutch simultaneously contained by the clutch corresponding to the current gear and the clutch corresponding to the required gear.

5. The control method of claim 4, wherein, The small-medium load upshift control comprises the following steps: lowering the oil pressure of the to-be-separated clutch at a first slope value, and pre-pressurizing the to-be-engaged clutch and then maintaining the to-be-engaged clutch at a first set oil pressure value, wherein the first set oil pressure value represents a set range value below a half-engaged oil pressure of the clutch; in response to the oil pressure of the to-be-separated clutch being lowered to 0 and the oil pressure of the to-be-engaged clutch being maintained at the first set oil pressure value, controlling the output torque of the drive motor to be lowered to a first torque set value; in response to a difference between the driving and driven speeds of the to-be-engaged clutch being less than a first speed difference set value, controlling the oil pressure of the to-be-engaged clutch to be raised to a target oil pressure value within a first time period and the output torque of the drive motor to be increased to an overall requested motor torque value within a second time period, and the shift is completed.

6. The control method of claim 5, wherein, The first torque set value is determined according to the difference between the driving and driven speeds of the to-be-engaged clutch before the shift and the output torque of the drive motor.

7. The control method of claim 4, wherein, The small-medium load downshift control comprises the following steps: lowering the oil pressure of the to-be-separated clutch at a first slope value, and pre-pressurizing the to-be-engaged clutch and then maintaining the to-be-engaged clutch at a second set oil pressure value, wherein the second set oil pressure value represents a set range value below a half-engaged oil pressure of the clutch; in response to the oil pressure of the to-be-separated clutch being lowered to 0 and the oil pressure of the to-be-engaged clutch being maintained at the first set oil pressure value, controlling the output torque of the drive motor to be raised to a second torque set value; In response to the difference between the driving and driven speeds of the to-be-engaged clutch being less than the second speed difference set value, the oil pressure of the to-be-engaged clutch is increased to the target oil pressure value in the first time period, and the output torque of the driving motor is decreased to the whole-machine requested motor torque value in the second time period, and the gear shifting is completed.

8. The control method of claim 7, wherein, The second torque set value is determined according to the difference between the driving and driven speeds of the to-be-engaged clutch and the output torque of the driving motor before gear shifting.

9. A control method of a power shift transmission of a working machine according to claim 5 or 7, characterized in that, At least one of the following conditions is met: The first slope value is the oil pressure drop rate when the oil inlet passage of the to-be-separated clutch is completely closed and the oil return passage is completely opened; The increase of the oil pressure of the to-be-engaged clutch to the target oil pressure value in the first time period means that the oil return passage of the to-be-engaged clutch is completely closed, the oil inlet passage is completely opened, and the to-be-engaged clutch is filled with oil to the maximum oil pressure; The second time period is determined by the difference between the actual torque value of the driving motor and the whole-machine requested motor torque value; The whole-machine requested motor torque value is determined according to the driving motor speed and the accelerator pedal opening degree.

10. The control method of claim 1, wherein, During the execution of the small-load upshift control or small-load downshift control process, if the speed drop rate of the gearbox output shaft is greater than the set speed value, the small-load upshift control or small-load downshift control is exited, and the oil pressure of the to-be-engaged clutch is increased to the target oil pressure value at the second slope value.

11. The method of control of the power shift transmission gear shifting process of the construction machine according to claim 10, characterized by, The second slope value is obtained by the speed change slope of the gearbox output shaft and the torque of the driving motor.

12. A control device for a shift process of an electrically driven transmission of a construction machine, characterized by comprising: The control device comprises a memory and a processor, and the memory is used to store instructions for controlling the processor to operate to perform the gear shifting process control method of the electric drive gearbox of the engineering machinery according to any one of claims 1-11.

13. A control system for an engineering machine electric drive gearbox shift process, characterised in that, The control device comprises the gear shifting process control device of the electric drive gearbox of the engineering machinery according to claim 12.

14. A working machine, characterized in that The control device comprises the gear shifting process control device of the electric drive gearbox of the engineering machinery according to claim 12 or the gear shifting process control system of the electric drive gearbox of the engineering machinery according to claim 13.

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