A working fence leveling control method and working fence leveling control system

Abstract

The present invention provides a work bar leveling control method and a work bar leveling control system, which relate to the field of aerial work equipment. The method comprises the following steps: obtaining a first boom difference Θ and a second boom difference Θ', calculating a feedforward difference between the second boom difference Θ' and the first boom difference Θ, and obtaining a feedforward control quantity Control1 based on the feedforward difference. The feedforward control quantity Control1 is a feedforward control quantity caused by boom changes. The method further comprises obtaining a first work bar difference ɑ and a second work bar difference ɑ', calculating a post-feedback difference between the second work bar difference ɑ' and the first work bar difference ɑ, and obtaining a post-feedback control quantity Control2 based on the post-feedback difference. The angle of the work bar is adjusted based on the sum of the feedforward control quantity Control1 and the post-feedback control quantity Control2. Since the influence of boom changes on the work bar is taken into account, the work bar can be leveled more smoothly, meeting the requirements for leveling safety, real-time performance, and smoothness.

Description

Technical Field

[0001] The present invention relates to the field of aerial work equipment, and further relates to a work bar leveling control method. In addition, the present invention also relates to a work bar leveling control system. Background Art

[0002] An aerial work platform is a type of construction machinery that uses a boom to transport construction workers to a designated height and location for construction work. Workers stand in a work rail mounted on the boom. With the introduction and improvement of domestic safety regulations and systems for aerial work, market demand for aerial work platforms is increasing year by year. Users are increasingly concerned about how to prevent the work rail from tipping over and maintain smooth operation when carrying people.

[0003] Currently, some work rail leveling devices use mechanical linkages, which use gears and chains to ensure that the work rail is linked to the boom as it moves, thus maintaining its levelness. However, mechanical linkage-type leveling mechanisms increase the design difficulty of the aerial work platform's working arm. As the working height of the aerial work platform increases, designing a mechanical leveling mechanism that moves with the working arm becomes almost impossible. Other work rail leveling devices use mechanical-hydraulic leveling methods, which adjust the work rail's level by controlling the oil pressure of the upper and lower boom cylinders. However, as the height of the working boom increases, the real-time responsiveness of the hydraulic system and the complexity of the hydraulic pipeline design cannot meet the requirements for leveling safety, real-time performance, and smoothness.

[0004] For those skilled in the art, how to smoothly level the work bar is a technical problem that needs to be solved. Summary of the Invention

[0005] The present invention provides a working bar leveling control method, which can perform feedforward and feedback adjustment on the working bar. The working bar leveling meets the requirements of safety, real-time performance and smoothness. The specific scheme is as follows:

[0006] A working column leveling control method, comprising:

[0007] Obtain a first boom difference Θ between the boom real-time sampling angle Θ1 and the boom initial angle Θ0 at time T1, and obtain a second boom difference Θ' between the boom real-time sampling angle Θ2 and the boom initial angle Θ0 at time T2;

[0008] Calculating a feedforward difference between the second boom difference Θ' and the first boom difference Θ, and obtaining a feedforward control amount Control1 according to the feedforward difference;

[0009] Obtain a first working bar difference value ɑ between the working bar real-time sampling angle ɑ1 and the working bar control target angle ɑ0 at time T1, and obtain a second working bar difference value ɑ' between the working bar real-time sampling angle ɑ2 and the working bar control target angle ɑ0 at time T2;

[0010] Calculating a post-feedback difference and a post-feedback difference change rate between the second working column difference ɑ' and the first working column difference ɑ, and obtaining a post-feedback control amount Control2 according to the post-feedback difference and the post-feedback difference change rate;

[0011] The angle adjustment amount of the working column is the sum of the feedforward control amount Control1 and the feedback control amount Control2.

[0012] Optionally, the post-feedback control amount Control2 = K1·(ɑ'-ɑ)+K2·ɑ'

[0013] K1 and K2 are both control coefficients;

[0014] ɑ=ɑ1-ɑ0, ɑ'=ɑ2-ɑ0;

[0015] Among them, the following conditions are met:

[0016] ①When ɑ'·ɑ>0, K2=K2;

[0017] ②When ɑ'·ɑ≦0, K2=-K2.

[0018] Optionally, the feedforward control quantity Control1 = -K0·(Θ'-Θ)

[0019] K0 is the control coefficient;

[0020] Θ=Θ1-Θ0, Θ'=Θ2-Θ0.

[0021] Optionally, it also includes judging whether the arm angle detector and the work column angle detector are normal, if not, ending, if yes, performing corresponding control.

[0022] The present invention also provides a work bar leveling control system, comprising:

[0023] An input module includes a boom luffing handle, a boom angle detector, and a work bar angle detector; the boom luffing direction is determined based on the boom luffing handle; the boom angle detector is used to detect the real-time sampling angle of the boom, and can obtain the boom initial angle Θ0, the real-time sampling angle Θ1 of the boom at time T1, and the real-time sampling angle Θ2 of the boom at time T2; the work bar angle detector is used to detect the real-time sampling angle of the work bar, and can obtain the work bar control target angle ɑ0, the real-time sampling angle ɑ1 of the work bar at time T1, and the real-time sampling angle ɑ2 of the work bar at time T2;

[0024] a control module, configured to receive input signals from the input module and to send adjustment signals, wherein the control module calculates a feedforward difference between the second boom difference Θ' and the first boom difference Θ, and obtains a feedforward control quantity Control1 based on the feedforward difference; calculates a rear feedback difference and a rear feedback difference change rate between the second working bar difference ɑ' and the first working bar difference ɑ, and obtains a rear feedback control quantity Control2 based on the rear feedback difference and the rear feedback difference change rate; and determines an angle of the working bar based on the sum of the feedforward control quantity Control1 and the rear feedback control quantity Control2;

[0025] The output module is used to receive the adjustment signal and perform the adjustment action.

[0026] Optionally, the output module includes a luffing cylinder and an electro-hydraulic proportional cartridge valve, and the angle of the working bar is adjusted by the luffing cylinder.

[0027] Compared to the prior art, the present invention provides a workbar leveling control method. The method comprises obtaining a first boom difference Θ and a second boom difference Θ', calculating a feedforward difference between the second boom difference Θ' and the first boom difference Θ, and obtaining a feedforward control variable Control1 based on the feedforward difference. The feedforward control variable Control1 is the feedforward control variable caused by boom changes. Furthermore, the method obtains a first workbar difference ɑ and a second workbar difference ɑ', calculating a post-feedback difference between the second workbar difference ɑ' and the first workbar difference ɑ, and obtaining a post-feedback control variable Control2 based on the post-feedback difference. The post-feedback control variable Control2 is the post-feedback control variable that is still insufficient to meet the workbar state requirements after boom changes and adjustments. The workbar angle is adjusted based on the sum of the feedforward control variables Control1 and Control2. By taking into account the impact of boom changes on the workbar, the workbar can be leveled more smoothly, meeting the requirements for leveling safety, real-time performance, and smoothness. Similarly, the workbar leveling control system can achieve the same technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is a flow chart of the two processes of boom upward luffing rotation and boom downward luffing rotation. DETAILED DESCRIPTION

[0030] The core of the present invention is to provide a working bar leveling control method, which can perform feedforward adjustment and feedback adjustment on the working bar, and the working bar leveling meets the requirements of safety, real-time performance and smoothness.

[0031] In order to enable those skilled in the art to better understand the technical solution of the present invention, the work bar leveling control method and the work bar leveling control system of the present invention will be described in detail in conjunction with the accompanying drawings and specific implementation methods.

[0032] The present invention provides a working column leveling control method, comprising the following steps:

[0033] Obtain the first boom difference Θ between the boom's real-time sampling angle Θ1 at time T1 and the boom's initial angle Θ0, that is, the first boom difference Θ=(Θ1-Θ0); obtain the second boom difference Θ' between the boom's real-time sampling angle Θ2 at time T2 and the boom's initial angle Θ0, that is, the second boom difference Θ'=(Θ2-Θ0). The acquisition of data relies on an angle detector. A boom angle detector is set on the boom to detect the actual angle of the boom in real time. The initial angle Θ0, the boom's real-time sampling angle Θ1 at time T1, and the boom's real-time sampling angle Θ2 at time T2 can be detected respectively. The boom angle detector detects the actual angle of the boom at a certain frequency. The boom's initial angle Θ0 is the angle from the boom's stationary state to the start of angle adjustment; time T1 and time T2 are two time points, time T1 is earlier than time T2. During the boom adjustment process, the angles at time T1 and time T2 are usually different.

[0034] The feedforward difference between the second boom difference Θ' and the first boom difference Θ is calculated, and the feedforward control value Control1 is obtained based on the feedforward difference. The feedforward control value Control1 is based on the influence of the boom itself on the workload angle when the angle changes. The work bar is adjusted accordingly according to the angle change of the boom, so that the angle of the work bar is adjusted at the same time as the boom changes.

[0035] Obtain the first working bar difference ɑ between the working bar's real-time sampling angle ɑ1 at time T1 and the working bar's control target angle ɑ0. Obtain the second working bar difference ɑ' between the working bar's real-time sampling angle ɑ2 at time T2 and the working bar's control target angle ɑ0. Data acquisition relies on an angle detector installed on the working bar to measure the working bar's actual angle in real time. The working bar's real-time sampling angle ɑ1 at time T1 and the working bar's real-time sampling angle ɑ2 at time T2 can be measured separately. The working bar's control target angle ɑ0 is the angle that the working bar should ideally achieve.

[0036] The post-feedback difference and the rate of change of the post-feedback difference between the second working bar difference ɑ' and the first working bar difference ɑ are calculated. The post-feedback control quantity Control2 is obtained based on the post-feedback difference and the rate of change of the post-feedback difference. After the boom adjusts the amplitude and performs feedforward adjustment on the working bar, there may be a difference between the actual angle of the working bar and the target control angle ɑ0 of the working bar. The working bar cannot reach the target control angle ɑ0 of the working bar, thus requiring post-feedback adjustment of the working bar. That is, the working bar is adjusted according to its actual angle. The post-feedback adjustment considers two parameters: the post-feedback difference and the rate of change of the post-feedback difference. Not only the difference between the actual angle of the working bar and the target control angle ɑ0 of the working bar is considered, but also the rate of change of this difference, to ensure a smoother translation adjustment process.

[0037] The angle adjustment amount of the work bar is the sum of the feedforward control amount Control1 and the feedback control amount Control2. The angle adjustment amount of the work bar includes two parts: feedforward adjustment and feedback adjustment. The feedforward adjustment is carried out simultaneously with the change of the arm angle. The feedback adjustment is a further adjustment when the feedforward adjustment still cannot meet the work bar angle requirement. The feedback adjustment includes two factors: the feedback difference and the rate of change of the feedback difference. Compared with the traditional method of relying solely on feedback adjustment, it can level the work bar more smoothly, meeting the requirements of work bar leveling safety, real-time performance and smoothness.

[0038] Specifically, the post-feedback control amount Control2 = K1·(ɑ'-ɑ)+K2·ɑ'

[0039] K1 and K2 are both control coefficients, which can be calculated through actual experiments.

[0040] ɑ=ɑ1-ɑ0, ɑ'=ɑ2-ɑ0; ɑ0 is the target angle of the working bar control, ɑ1 is the real-time sampling angle of the working bar at time T1, and ɑ2 is the real-time sampling angle of the working bar at time T2.

[0041] Among them, the following conditions are met:

[0042] ① When ɑ'·ɑ>0, K2=K2; ɑ'·ɑ>0 means that the angle adjustment directions at time T1 and time T2 are the same.

[0043] ② When ɑ'·ɑ≦0, K2=-K2; ɑ'·ɑ≦0 means that the angle adjustment directions at time T1 and time T2 are opposite.

[0044] In the above formula Control2=K1·(ɑ'-ɑ)+K2·ɑ', K1·(ɑ'-ɑ) represents the rate of change of the post-feedback difference, and K2·ɑ' represents the post-feedback difference; the rate of change of the post-feedback difference is also the angle difference between time T2 and time T1.

[0045] Furthermore, in the present invention, the feedforward control quantity Control1 = -K0·(Θ'-Θ)

[0046] K0 is the control coefficient, which can be calculated through actual experiments.

[0047] Θ=Θ1-Θ0, Θ'=Θ2-Θ0; Θ0 is the initial angle of the boom, Θ1 is the real-time sampling angle of the boom at time T1, and Θ2 is the real-time sampling angle of the boom at time T2.

[0048] Before the arm angle detector and the work bar angle detector are used for detection, it is first determined whether the arm angle detector and the work bar angle detector are normal. If not, the adjustment process is terminated; if so, corresponding control is performed.

[0049] The present invention also provides a workbar leveling control system, comprising an input module, a control module, and an output module. The input module includes a boom luffing handle, a boom angle detector, and a workbar angle detector. The boom luffing handle is used to control the boom's upward or downward luffing, and the direction of the boom luffing is determined based on the boom luffing handle. The boom angle detector is used to detect the boom's real-time sampling angle, capable of obtaining the boom's initial angle θ0, the boom's real-time sampling angle θ1 at time T1, and the boom's real-time sampling angle θ2 at time T2. The workbar angle detector is used to detect the workbar's real-time sampling angle, capable of obtaining the workbar's control target angle ɑ0, the workbar's real-time sampling angle ɑ1 at time T1, and the workbar's real-time sampling angle ɑ2 at time T2. The input module acquires external information data, which is then transmitted to the control module.

[0050] The control module is used to receive input signals from the input module and can send adjustment signals. The control module is the core of the entire system. Its main function is to perform logical operations to achieve control and adjustment. The control module calculates the feedforward difference between the second boom difference Θ' and the first boom difference Θ, and obtains the feedforward control quantity Control1 based on the feedforward difference; calculates the feedback difference between the second working bar difference ɑ' and the first working bar difference ɑ, and obtains the feedback control quantity Control2 based on the feedback difference; and determines the angle of the working bar according to the sum of the feedforward control quantity Control1 and the feedback control quantity Control2.

[0051] The output module is used to receive the adjustment signal and perform the adjustment action. The output module is an actuator that controls the angle adjustment of the working column.

[0052] Specifically, the output module includes a luffing cylinder and an electro-hydraulic proportional cartridge valve, and the angle of the working bar is adjusted by the luffing cylinder.

[0053] The present invention intervenes in the leveling control in advance by adding the forward feedback control; introduces the working bar leveling deviation angle (i.e., the difference from the rear feedback) and the deviation angle change rate (i.e., the difference from the rear feedback) to perform leveling control on the working bar. Figure 1 , which shows the process flow diagrams of the two processes of boom upward amplitude rotation and boom downward amplitude rotation. The present invention adds a composite closed-loop electro-hydraulic leveling method based on negative feedback + feedforward on the basis of the hydraulic leveling device, wherein the electrical system includes three parts: input module: boom amplitude change handle, boom angle detector, work bar angle detector; control module: vehicle platform control unit; output module: amplitude change cylinder, electro-hydraulic proportional cartridge valve. The boom amplitude change handle is used to determine the direction of the boom amplitude change (up or down). When the boom amplitude change is operated downward, the work bar leveling cylinder is controlled to automatically level upward. When the boom amplitude change is operated upward, the work bar leveling cylinder is controlled to automatically level downward.

[0054] The boom angle detector is used for feedforward control in the compound closed-loop control, that is, according to the direction trend of the boom amplitude change, the leveling direction is intervened in advance, that is, Control 调上1 =-△f(Control 变幅下 ,Θ) or Control 调下1 =-△f(Control 变幅上 ,Θ), where Control 调上1 The current control value of the electro-hydraulic proportional valve on the working column leveling, △f (Control 变幅下 , Θ) is the current control quantity under the relationship between the boom cylinder amplitude change and the amplitude change angle Θ, Control 调下1 The current control value of the electro-hydraulic proportional valve under the working column leveling, △f (Control 变幅上 , Θ) is the current control quantity under the correlation relationship between the boom cylinder amplitude change and the amplitude change angle Θ; the working bar angle detector is used for negative feedback control in the compound closed-loop control, that is, Control 调上2＝ △f(α)+△f(β) or Control 调下2＝ △f(α)+△f(β), where α is the angle difference signal between the target value and the actual value in the absolute horizontal direction of the work bar, and β is the angle difference change rate signal between the target value and the actual value in the absolute horizontal direction of the work bar; In summary, the current control quantity acting on the oil cylinder of the work bar leveling is Control 调上 =Control 调上1 +Control 调上2 , Control 调下 =Control 调下1 +Control 调下2 .

[0055] The present invention can effectively reduce the overshoot phenomenon in the leveling process of the work bar by identifying the leveling deviation angle and the deviation angle change rate of the work bar in the negative feedback, thereby reducing the frequency of the work bar swinging up and down, and making the operation of the staff more stable; by adding forward feedback control, that is, through the change of the boom amplitude angle, the leveling control amount of the work bar is predicted in advance, thereby improving the response speed in the leveling process, reducing lag, and improving the leveling angle control accuracy.

[0056] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A working column leveling control method, characterized in that: include: Obtain a first boom difference Θ between the boom real-time sampling angle Θ1 and the boom initial angle Θ0 at time T1, and obtain a second boom difference Θ' between the boom real-time sampling angle Θ2 and the boom initial angle Θ0 at time T2; Calculating a feedforward difference between the second boom difference Θ' and the first boom difference Θ, and obtaining a feedforward control amount Control1 according to the feedforward difference; Obtain a first working bar difference value ɑ between the working bar real-time sampling angle ɑ1 and the working bar control target angle ɑ0 at time T1, and obtain a second working bar difference value ɑ' between the working bar real-time sampling angle ɑ2 and the working bar control target angle ɑ0 at time T2; Calculating a post-feedback difference and a post-feedback difference change rate between the second working column difference ɑ' and the first working column difference ɑ, and obtaining a post-feedback control amount Control2 according to the post-feedback difference and the post-feedback difference change rate; The angle adjustment amount of the working bar is the sum of the feedforward control amount Control1 and the feedback control amount Control2; The post-feedback control quantity Control2 = K1·(ɑ'-ɑ)+K2·ɑ' K1 and K2 are both control coefficients; ɑ=ɑ1-ɑ0, ɑ'=ɑ2-ɑ0; Among them, the following conditions are met: ①When ɑ'·ɑ>0, K2=K2; ②When ɑ'·ɑ≦0, K2=-K2; The feedforward control quantity Control1=-K0·(Θ'-Θ) K0 is the control coefficient; Θ=Θ1-Θ0, Θ'=Θ2-Θ0.

2. The working column leveling control method according to claim 1, characterized in that: It also includes judging whether the arm angle detector and the work column angle detector are normal. If not, the process ends; if so, corresponding control is performed.

3. A work rail leveling control system, applied to the work rail leveling control method according to claim 1 or 2, characterized in that: include: The input module includes a boom luffing handle, a boom angle detector, and a work bar angle detector; the direction of the boom luffing is determined according to the boom luffing handle; The boom angle detector is used to detect the real-time sampling angle of the boom, and can obtain the boom initial angle Θ0, the real-time sampling angle Θ1 of the boom at time T1, and the real-time sampling angle Θ2 of the boom at time T2; the working bar angle detector is used to detect the real-time sampling angle of the working bar, and can obtain the working bar control target angle ɑ0, the real-time sampling angle ɑ1 of the working bar at time T1, and the real-time sampling angle ɑ2 of the working bar at time T2; a control module, configured to receive input signals from the input module and to send adjustment signals, wherein the control module calculates a feedforward difference between the second boom difference Θ' and the first boom difference Θ, and obtains a feedforward control quantity Control1 based on the feedforward difference; calculates a rear feedback difference and a rear feedback difference change rate between the second working bar difference ɑ' and the first working bar difference ɑ, and obtains a rear feedback control quantity Control2 based on the rear feedback difference and the rear feedback difference change rate; and determines an angle of the working bar based on the sum of the feedforward control quantity Control1 and the rear feedback control quantity Control2; The output module is used to receive the adjustment signal and perform the adjustment action.

4. The work bar leveling control system according to claim 3, characterized in that: The output module includes a variable-length oil cylinder and an electro-hydraulic proportional cartridge valve, and the angle of the working bar is adjusted by the variable-length oil cylinder.

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