阅读说明：本技术 上装作业中汽车起重机底盘的姿态保持自动控制方法 (Automatic control method for maintaining attitude of automobile crane chassis in loading operation ) 是由 张帆 杨文韬 刘爱冰 刚宪约 吴振华 武际兴 王慧恒 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种上装作业中汽车起重机底盘的姿态保持自动控制方法,包括以下步骤：首先,测试并获取各支腿的等效刚度,根据各支腿载荷计算起重机质心坐标位置和吊重质量,进而建立汽车起重机及吊重整体的质心坐标参数化模型与支腿补偿作动量模型；然后,计算并判断执行吊重起升离地引起平台侧倾需要的的支腿补偿作动；最后,识别驾驶员指令,预算并构建支腿补偿作动量矩阵,同步控制上装作业和支腿补偿作动,直至姿态保持控制结束。该方法通过上装作业和支腿补偿同步控制,有效的保持了汽车起重机作业过程中姿态实时稳定,无滞后和超调问题,彻底消除了平台倾覆风险；实现了姿态保持自动控制,保障了驾驶员人身安全,提高了工作效率。(The invention discloses an automatic control method for maintaining the posture of an automobile crane chassis in loading operation, which comprises the following steps: firstly, testing and obtaining equivalent stiffness of each support leg, calculating the coordinate position of the mass center of the crane and the mass of the hoisting weight according to the load of each support leg, and further establishing a mass center coordinate parameterized model of the automobile crane and the whole hoisting weight and a support leg compensation action amount model; then, calculating and judging the supporting leg compensation action required by the side inclination of the platform caused by lifting of the hoisting weight; and finally, recognizing a driver instruction, budgeting and constructing a support leg compensation actuation quantity matrix, and synchronously controlling the loading operation and the support leg compensation actuation until the attitude keeping control is finished. The method effectively keeps the real-time stability of the attitude of the truck crane in the operation process through the synchronous control of the loading operation and the supporting leg compensation, has no problems of lag and overshoot, and thoroughly eliminates the risk of platform overturning; the automatic control of the posture is realized, the personal safety of a driver is guaranteed, and the working efficiency is improved.)

1. The invention discloses an automatic control method for maintaining the posture of a chassis of a truck crane in loading operation, wherein a luffing cylinder drives a crane boom to ascend and descend at an equal angular speed, a slewing mechanism drives the crane boom to rotate at an equal angular speed, and each level of crane boom is driven by a telescoping mechanism to stretch at a constant speed; the effective lengths of all levels of the crane booms are the same, the mass distribution is uniform, and the crane booms higher than the first level are overlapped and arranged in the next level of the crane boom; a displacement sensor for measuring the extension length of the second-stage crane boom is arranged between the second-stage crane boom and the first-stage crane boom, a rotation angle sensor for measuring the rotation angle of the crane boom relative to the longitudinal symmetrical surface of the chassis is arranged on the slewing mechanism, and a displacement sensor for measuring the extension length of the luffing cylinder and equivalently calculating the luffing angle of the crane boom is arranged on the luffing cylinder; the upper ends of the four support legs are vertically inserted into mounting holes of an overhanging beam on the chassis at equal height, the lower ends of the four support legs are supported on the ground, the structural size and the maximum actuation stroke of each support leg are completely the same, and each support leg is provided with a force sensor for measuring the vertical load of the support leg and a displacement sensor for measuring the actuation amount of the support leg; the geometric center of the slewing mechanism is positioned at the central position of the rectangle determined by the four supporting legs; a two-dimensional inclination angle sensor is arranged at the central position of the slewing mechanism to measure a two-dimensional inclination angle of the chassis relative to a horizontal plane; under the initial state, the four support legs support the chassis to a tire suspension and geometric horizontal state, each support leg bears uniform load, the crane boom runs to a hoisting position, the hoisting is completed, and the suspension and the loading of the hoisting are not completed, but the hoisting is carried out off the ground, and the method is characterized by comprising the following steps of:

step 1, measuring the equivalent stiffness of each supporting leg, specifically: driving 1 supporting leg to extend for a vertical displacement and then shortening the supporting leg to the original length, wherein other supporting legs except the supporting leg are not moved in the period, and measuring the load increment of the supporting leg when the supporting leg extends to the vertical displacement by using a displacement sensor and a force sensor on the supporting leg; dividing the load increment by the vertical displacement to obtain the equivalent stiffness of the supporting leg; measuring the equivalent stiffness of other 3 support legs by adopting the same process; numbering according to the support legs, and respectively recording the equivalent stiffness as k_i，i＝1～4；

Step 2, calculating the total weight and the mass center coordinate position of the automobile crane, specifically: measuring the vertical load of each support leg in the initial state by a force sensor, and recording the vertical load as F_iI is 1-4; establishing a coordinate system by taking the geometric center of the upper surface of the slewing mechanism as the origin of coordinates,the vertical, horizontal and vertical directions along the chassis are respectively the x, y and z axes of a coordinate system, and the vertical and horizontal coordinates of each supporting leg are marked as (x)_i，y_i) Judging the positive directions of the moment and the inclination angle according to the right-hand spiral rule, and recording the total weight of the automobile crane as G; calculating the gross weight of the truck crane and the longitudinal and transverse coordinates (x and x) of the mass center of the gross weight according to the measured vertical load of each supporting leg, the moment balance of the truck crane around the x and y axes and the force balance along the z axis_mc,y_mc) Is composed of

Step 3, calculating the hoisting weight, specifically: driving the amplitude cylinder to actuate to lift the hoisting weight to the ground, measuring the vertical load of each supporting leg again, and calculating the total weight G' of the automobile crane and the hoisting weight so as to calculate the mass M of the hoisting weight;

step 4, establishing a mass center coordinate parameterization model of the automobile crane and the hoisting weight whole body, specifically comprising the following steps: and establishing a mass center coordinate (x ') of the automobile crane and the hoisting weight whole according to the parameters, the inherent amplitude, the rotation speed and the stretching speed of the automobile crane in the initial state and the mass and size characteristics of each structure of the automobile crane'_mc,y′_mc) Parameterized model

In the formula, m_iI is 1-n, n is the number of crane arm stages, l is the mass of the ith crane arm_aAs regards the length of the jib,to complete the initial amplitude angle of the crane boom, the elevation angle is positive, omega_bFor changing the amplitude angular velocity of the boom, so that the boom is raised to be positive, t_bFor variable amplitude actuation time, /)_jIs the horizontal distance, m, from the rotary shaft of the jib to the origin_bFor the mass of the counterweight, /)_bFor horizontal distance of counterweight to origin,/₀To complete the initial extension, v, of the boom at each level of the hoist_sThe boom extension/contraction speed is determined so that the boom is positively extended, t_sFor the telescopic actuation time of the jib₀For completing the initial rotation angle, omega, of the boom_hIs the boom rotation angular velocity, positive with counterclockwise rotation about the z-axis, t_hFor the time of the rotation, m_tAs chassis mass, x_tX-axis coordinate of chassis centroid, y_tY-axis coordinates of the chassis centroid;

step 5, when the platform is tilted due to the loading operation, a compensation action quantity model required for restoring the platform to a horizontal state by each supporting leg is established, and the method specifically comprises the following steps: according to the equivalent rigidity k of each supporting leg_iVertical load F of each leg in the initial state_iWeight and center of mass coordinate (x ') of the truck crane and hoist weight assembly'_mc,y′_mc) Establishing a compensation action quantity model of each supporting leg according to the statics balance relation

Where b is the longitudinal span of the leg, L is the transverse span of the leg, Δ z₁～Δz₄Are respectively the centroid of_mc,y_mc) Move to (x'_mc,y′_mc) The compensation action amounts of the four supporting legs required for keeping the chassis in a horizontal state are kept, and the positive and negative values of the compensation action amounts correspond to the rising and falling actions of the supporting legs respectively;

step 6, respectively measuring the inclination angles of the chassis around the x axis and the y axis after the hoisting load lifts off the ground by using a two-dimensional inclination angle sensor; according to the formula betax_i-αy_iCalculating compensation acting amount of each support leg required by leveling, wherein alpha and beta are the inclination angles of the lower bottom in the current state around x and y axes respectively;

and 7, executing support leg compensation corresponding to hoisting and lifting, specifically: setting a roll threshold epsilon of the chassis_θRespectively calculating the absolute values of the inclination angles of the bottom disc around the x axis and the y axis;if the absolute values of both inclination angles are smaller than the roll threshold epsilon_θIf not, controlling the supporting legs to synchronously act according to the proportional relation of the absolute values of the compensation acting amount of each supporting leg until the compensation acting amount is executed;

step 8, identifying a driver instruction, and estimating leg compensation actuation data, specifically: monitoring and identifying amplitude variation, rotation and expansion commands of a driver for operating the upper device, and controlling the upper device to execute the corresponding action of the commands; setting unit time intervals, and budgeting the position coordinates of the mass center of the whole automobile crane and the hoisting weight corresponding to the instruction of a driver in m unit time intervals according to a formula (2); respectively substituting the position coordinates of the mass center in the m unit time intervals into a formula (3) to calculate the compensation acting amount of each supporting leg in the m unit time intervals; directly putting the compensation action amount of the 1 st unit time interval into the first row of an m multiplied by 4 dimensional matrix, respectively subtracting the compensation action amount data of the previous unit time interval from the compensation action amount data of the p unit time interval, wherein p is more than or equal to 2, and sequentially putting the compensation action amount data of the previous unit time interval into the p row of the m multiplied by 4 dimensional matrix to form an m multiplied by 4 dimensional landing leg compensation action amount matrix; setting the execution times k to be 0;

step 9, executing the top-loading action and the supporting leg compensation action at unit time interval, specifically: adding 1 to the execution times k, driving the amplitude variation cylinder, the swing mechanism and the telescopic mechanism to execute amplitude variation, swing and telescopic actions of the upper device at a unit time interval according to amplitude variation, swing and telescopic instructions of the upper device operated by a driver, and synchronously executing the compensation actuation of the supporting legs according to the kth data in the compensation actuation quantity matrix;

step 10, respectively measuring the inclination angles of the base plate around an x axis and a y axis by using a two-dimensional inclination angle sensor, and calculating the absolute values of the two inclination angles; if the absolute values of both inclination angles are smaller than the roll threshold epsilon_θStep 11 is executed, otherwise, the supporting legs are manually adjusted to adjust the chassis to a geometric horizontal state, all the supporting legs bear uniform load, step 1 is executed again, the set unit time interval is shortened, and then step 8 is executed;

step 11, monitoring and identifying the amplitude variation, rotation, expansion and contraction instructions of the driver for operating the upper loader and the lowering hoisting instruction, specifically comprising the following steps:

if the driver operates the amplitude variation, rotation and expansion instructions of the upper device continuously, executing a step 9;

if the driver operates the change of the amplitude, rotation and expansion commands of the upper device or the compensation actuation of the upper device and the supporting legs at m unit time intervals is finished, executing the step 8;

if the driver operates the lowering and hoisting instruction, the force sensors on the support legs measure vertical loads, when the total vertical load is recovered to the total weight G of the automobile crane from the total weight G' of the automobile crane and the hoisting weight, the two-dimensional inclination angle sensor is used for measuring the inclination angles of the bottom disc around the x axis and the y axis, and the absolute values of the two inclination angles are calculated;

if both absolute values are smaller than the roll threshold epsilon_θThen the leg compensation is not performed and step 12 is performed, otherwise, according to the formula β x_i-αy_iCalculating compensation acting amount of each supporting leg required by leveling, controlling the supporting legs to synchronously act according to the proportional relation of the absolute values of the compensation acting amount of each supporting leg until the compensation acting amount is executed, and executing the step 12;

if the driver instructs to stop, executing step 12;

step 12, stopping the loading action and the supporting leg compensation action, measuring the vertical load by the force sensors on the supporting legs, and executing step 8 if the total vertical load is the total weight G' of the automobile crane and the hoisting weight;

if the total vertical load is reduced to the gross weight G of the automobile crane, the total vertical load is measured and calculated in real time until a new hoisting weight lifts off the ground, and the amplitude variation angle of the hoisting arm at the moment is read as the initial amplitude variation angleThe extension length is taken as the initial extension length l₀The angle of revolution being said initial angle of revolution psi₀Substituting the formula (2) and further executing the step 8;

and step 13, the driver forcibly turns off the attitude keeping automatic control or turns off the main power supply of the automobile crane, and the attitude keeping control is finished.

2. The method for automatically controlling the attitude of the chassis of the automobile crane in the loading operation according to claim 1, wherein the vertical displacement in the step 1 is 1-5% of the maximum actuating stroke of the supporting leg.

3. The automatic attitude keeping control method for a crane truck chassis during a loading operation according to claim 1, wherein the roll threshold e of step 7 is_θThe range is 0.2-0.5 degrees.

4. The method for automatically controlling the attitude keeping of the chassis of the truck crane in the loading operation according to claim 1, wherein m in the step 8 is in the range of 2 to 10; the unit time interval is in the range of 1 second to 5 seconds.

Technical Field

The invention belongs to the field of attitude control, and particularly relates to an automatic attitude keeping control method for an automobile crane chassis in loading operation.

Background

Although the truck crane has been adjusted in horizontal attitude by means of a multi-legged support structure before work to improve the rigidity and stability of the upper mounting platform, there is no effective means for maintaining the stable attitude of the work platform during work. Accidents in engineering work are mostly caused by the fact that the stability of equipment in work is damaged, and the horizontal posture adjusted before work cannot support a work platform to keep balance. In order to ensure that the horizontal posture of the operation platform can be kept during operation, the posture of the operation platform under time-varying working conditions needs to be kept and controlled, and new and higher requirements are provided for leveling technologies.

At present, chinese patent CN201911224336.5 discloses an automatic adjustment and control method and system for operating posture of crane working device, wherein the method comprises measuring initial attitude of equipment by using an angle sensor of a boom or a length sensor of a boom cylinder, calculating a difference value between the initial attitude and the attitude of the equipment in an ideal state, and generating a control signal to adjust the posture of the crane working device in real time.

It can be found that those skilled in the art can monitor the attitude of the platform by optimizing the structure or using advanced measurement and control equipment to compensate and control the attitude of the platform to achieve the purpose of controlling the attitude of the platform. In fact, the problem caused by mass center offset cannot be really solved through structural optimization, the attitude control by using auxiliary equipment is also compensation control after the platform is inclined in attitude, the problems of hysteresis and overshoot exist, and the method has many limitations and uncontrollable performance, cannot fundamentally improve the stability of the platform and avoids the occurrence of overturning accidents.

Disclosure of Invention

In view of the defects, the invention provides the automatic control method for maintaining the attitude of the chassis of the automobile crane in the loading operation, the strategy fully considers the essence that the attitude of the chassis is changed due to the deviation of the center of mass of equipment in the loading operation, and synchronously controls the loading operation and the actuating compensation of each supporting leg based on the characteristic of the attitude change of the chassis possibly caused by the deviation of the center of mass calculated in advance, thereby effectively solving the problem that the attitude of the chassis is damaged and even the crane overturns due to the deviation of the center of mass of the crane in the operation process.

The embodiment of the invention provides an automatic control method for maintaining the posture of a chassis of a truck crane in loading operation, wherein a luffing cylinder drives a crane boom to ascend and descend at an equal angular speed, a slewing mechanism drives the crane boom to rotate at an equal angular speed, and each level of crane boom is driven by a telescoping mechanism to stretch at a constant speed; the effective lengths of all levels of the crane booms are the same, the mass distribution is uniform, and the crane booms higher than the first level are overlapped and arranged in the next level of the crane boom; a displacement sensor for measuring the extension length of the second-stage crane boom is arranged between the second-stage crane boom and the first-stage crane boom, a rotation angle sensor for measuring the rotation angle of the crane boom relative to the longitudinal symmetrical surface of the chassis is arranged on the slewing mechanism, and a displacement sensor for measuring the extension length of the luffing cylinder and equivalently calculating the luffing angle of the crane boom is arranged on the luffing cylinder; the upper ends of the four support legs are vertically inserted into mounting holes of an overhanging beam on the chassis at equal height, the lower ends of the four support legs are supported on the ground, the structural size and the maximum actuation stroke of each support leg are completely the same, and each support leg is provided with a force sensor for measuring the vertical load of the support leg and a displacement sensor for measuring the actuation amount of the support leg; the geometric center of the slewing mechanism is positioned at the central position of the rectangle determined by the four supporting legs; a two-dimensional inclination angle sensor is arranged at the central position of the slewing mechanism to measure a two-dimensional inclination angle of the chassis relative to a horizontal plane; under the initial state, the four support legs support the chassis to a tire suspension and geometric horizontal state, each support leg bears uniform load, the crane boom runs to a hoisting position, the hoisting is completed, but the hoisting is not lifted off the ground, and the method comprises the following steps:

step 1, measuring the equivalent stiffness of each supporting leg, specifically: driving 1 supporting leg to extend for a vertical displacement and then to shorten the length to the original length, wherein other supporting legs except the supporting leg are not moved, and measuring the extension of the supporting leg to the vertical position by a displacement sensor and a force sensor on the supporting legLoad increment of the leg during shifting; dividing the load increment by the vertical displacement to obtain the equivalent stiffness of the supporting leg; measuring the equivalent stiffness of other 3 support legs by adopting the same process; the equivalent stiffness of each leg is respectively marked as k according to the number of the leg_i，i＝1～4。

Step 2, calculating the total weight and the mass center coordinate position of the automobile crane, specifically: measuring the vertical load of each support leg in the initial state by a force sensor, and recording the vertical load as F_iI is 1-4; establishing a coordinate system by taking the geometric center of the upper surface of the slewing mechanism as a coordinate origin, respectively taking the vertical, horizontal and vertical directions of the chassis as the x, y and z axes of the coordinate system, and recording the vertical and horizontal coordinates of each supporting leg as (x)_i，y_i) The positive directions of the moment and the inclination angle are judged according to the right-hand spiral rule; calculating the gross weight of the truck crane and longitudinal and transverse coordinates (x) of the mass center of the gross weight of the truck crane according to the measured vertical load of each landing leg, the moment balance of the truck crane around the x axis and the y axis and the force balance along the z axis_mc,y_mc) Is composed of

Step 3, calculating the hoisting weight, specifically: and driving the amplitude cylinder to actuate to lift the hoisting weight to the ground, measuring the vertical load of each supporting leg again, and calculating the total weight G' of the automobile crane and the hoisting weight so as to calculate the mass M of the hoisting weight.

Step 4, establishing a mass center coordinate parameterization model of the automobile crane and the hoisting weight whole body, specifically comprising the following steps: establishing a mass center coordinate (x ') of the automobile crane and the whole hoisting weight according to the parameters of the automobile crane in the initial state, namely the initial extension length, the initial rotation angle and the initial amplitude variation angle of each level of crane arm after the hoisting and hanging, the amplitude variation, the rotation and the stretching speed inherent to the automobile crane and the mass and size characteristics of each structure of the automobile crane'_mc,y′_mc) Parameterized model

In the formula, m_iI is 1-n, n is the number of crane arm stages, l is the mass of the ith crane arm_aAs regards the length of the jib,to complete the initial amplitude angle of the crane boom, the elevation angle is positive, omega_bFor changing the amplitude angular velocity of the boom, so that the boom is raised to be positive, t_bFor variable amplitude actuation time, /)_jIs the horizontal distance, m, from the rotary shaft of the jib to the origin_bFor the mass of the counterweight, /)_bFor horizontal distance of counterweight to origin,/₀To complete the initial extension, v, of the boom at each level of the hoist_sThe boom extension/contraction speed is determined so that the boom is positively extended, t_sFor the telescopic actuation time of the jib₀For completing the initial rotation angle, omega, of the boom_hIs the boom rotation angular velocity, positive with counterclockwise rotation about the z-axis, t_hFor the time of the rotation, m_tAs chassis mass, x_tX-axis coordinate of chassis centroid, y_tIs the y-axis coordinate of the center of mass of the chassis.

Step 5, when the platform is tilted due to the loading operation, a compensation action quantity model required for restoring the platform to a horizontal state by each supporting leg is established, and the method specifically comprises the following steps: according to the equivalent rigidity k of each supporting leg_iVertical load F of each leg in the initial state_iWeight and center of mass coordinate (x ') of the truck crane and hoist weight assembly'_mc,y′_mc) Establishing a compensation action quantity model of each supporting leg according to the statics balance relation

Where b is the longitudinal span of the four legs, L is the transverse span of the four legs, Δ z₁～Δz₄Are respectively the centroid of_mc,y_mc) Move to (x'_mc,y′_mc) While keeping the chassis horizontalThe positive and negative values of the compensation action amounts of the four support legs required by the state respectively correspond to the rising and falling actions of the support legs;

step 6, respectively measuring the inclination angles of the chassis around the x axis and the y axis after the hoisting load lifts off the ground by using a two-dimensional inclination angle sensor; according to the formula betax_i-αy_iAnd calculating compensation acting amount of each support leg required by leveling, wherein alpha and beta are the inclination angles of the lower bottom in the current state around x and y axes respectively.

And 7, executing support leg compensation corresponding to hoisting and lifting, specifically: setting a roll threshold epsilon of the chassis_θRespectively calculating the absolute values of the inclination angles of the bottom disc around the x axis and the y axis; if the absolute values of both inclination angles are smaller than the roll threshold epsilon_θAnd if not, controlling the supporting legs to synchronously act according to the proportional relation of the absolute values of the compensation acting amount of the supporting legs until the compensation acting amount is executed.

Step 8, identifying a driver instruction, and estimating leg compensation actuation data, specifically: monitoring and identifying amplitude variation, rotation and expansion commands of a driver for operating the upper device, and controlling the upper device to execute the corresponding action of the commands; setting unit time intervals, and budgeting the position coordinates of the mass center of the whole automobile crane and the hoisting weight corresponding to the instruction of a driver in m unit time intervals according to a formula (2); respectively substituting the position coordinates of the mass center in the m unit time intervals into a formula (3) to calculate the compensation acting amount of each supporting leg in the m unit time intervals; directly putting the compensation action amount of the 1 st unit time interval into the first row of an m multiplied by 4 dimensional matrix, respectively subtracting the compensation action amount data of the previous unit time interval from the compensation action amount data of the p unit time interval, wherein p is more than or equal to 2, and sequentially putting the compensation action amount data of the previous unit time interval into the p row of the m multiplied by 4 dimensional matrix to form an m multiplied by 4 dimensional landing leg compensation action amount matrix; the number of executions k is set to 0.

Step 9, executing the top-loading action and the supporting leg compensation action at unit time interval, specifically: and adding 1 to the execution times k, driving the amplitude variation cylinder, the swing mechanism and the telescopic mechanism to execute the amplitude variation, the swing and the telescopic actions of the upper device at a unit time interval according to the amplitude variation, the swing and the telescopic instructions of the upper device operated by a driver, and synchronously executing the compensation action of the supporting legs according to the kth data in the compensation action matrix.

Step 10, respectively measuring the inclination angles of the base plate around an x axis and a y axis by using a two-dimensional inclination angle sensor, and calculating the absolute values of the two inclination angles; if the absolute values of both inclination angles are smaller than the roll threshold epsilon_θAnd step 11 is executed, otherwise, the supporting legs are manually adjusted to adjust the chassis to a geometric horizontal state, all the supporting legs bear uniform load, step 1 is executed again, the set unit time interval is shortened, and then step 8 is executed.

Step 11, monitoring and identifying the amplitude variation, rotation, expansion and contraction instructions of the driver for operating the upper loader and the lowering hoisting instruction, specifically comprising the following steps:

if the driver operates the amplitude variation, rotation and expansion instructions of the upper device continuously, executing a step 9;

if the driver operates the change of the amplitude, rotation and expansion commands of the upper device or the compensation actuation of the upper device and the supporting legs at m unit time intervals is finished, executing the step 8;

if the driver operates the lowering and hoisting instruction, the force sensors on the support legs measure vertical loads, when the total vertical load is recovered to the total weight G of the automobile crane from the total weight G' of the automobile crane and the hoisting weight, the two-dimensional inclination angle sensor is used for measuring the inclination angles of the bottom disc around the x axis and the y axis, and the absolute values of the two inclination angles are calculated;

if both absolute values are smaller than the roll threshold epsilon_θThen the leg compensation is not performed and step 12 is performed, otherwise, according to the formula β x_i-αy_iCalculating compensation acting amount of each supporting leg required by leveling, controlling the supporting legs to synchronously act according to the proportional relation of the absolute values of the compensation acting amount of each supporting leg until the compensation acting amount is executed, and executing the step 12;

if the driver instructs a stop, step 12 is executed.

Step 12, stopping the loading action and the supporting leg compensation action, measuring the vertical load by the force sensors on the supporting legs, and executing step 8 if the total vertical load is the total weight G' of the automobile crane and the hoisting weight; if it isThe total vertical load is reduced to the gross weight G of the automobile crane, the total vertical load is measured and calculated in real time until a new hoisting weight lifts off the ground, and the amplitude variation angle of the hoisting arm at the moment is read as the initial amplitude variation angleThe extension length is taken as the initial extension length l₀The angle of revolution being said initial angle of revolution psi₀The formula (2) is substituted, and step 8 is executed.

And step 13, the driver forcibly turns off the attitude keeping automatic control or turns off the main power supply of the automobile crane, and the attitude keeping control is finished.

Further, the specific vertical displacement in the step 1 is 1-5% of the maximum actuating stroke of the support leg.

Further, the roll threshold ε is set forth in step 7_θThe range is 0.2-0.5 degrees.

Further, m in the step 8 is in a range of 2-10; the unit time interval is in the range of 1 second to 5 seconds.

The technical conception of the invention is as follows: aiming at the engineering problem that the attitude of the automobile crane is changed due to the change of the mass center in the process of loading operation after the leveling of the automobile crane is finished, even overturning accidents can be caused, firstly, the equivalent stiffness of each supporting leg is tested and obtained, the mass center coordinate position and the lifting weight mass of the crane are calculated according to the load of each supporting leg, and then a mass center coordinate parameterization model and a supporting leg compensation actuation amount model of the whole automobile crane and the lifting weight are established. Then, the compensation action of each supporting leg required for executing the lifting of the hoisting weight to lift off the ground to cause the platform to roll is calculated and judged. And finally, recognizing a driver instruction, budgeting and constructing a support leg compensation actuation quantity matrix, and synchronously controlling the loading operation and the support leg compensation actuation until the attitude keeping control is finished so as to achieve the effect of stably keeping the attitude of the chassis in the whole process of the loading operation of the automobile crane.

The invention has the following beneficial effects:

1. the calculation model provided by the method can estimate the mass center change coordinate when the truck crane performs the loading operation, and the support leg compensation actuation is performed while the truck crane performs the loading operation, so that the real-time stability of the attitude of the truck crane in the operation process is effectively kept, the problems of lag and overshoot existing in PID control are avoided, and the risk of platform overturning is thoroughly eliminated.

2. The method provides a plurality of sub-cycle judgment strategies, ensures the safety and integrity of the method, and ensures that the engineering risk caused by wrong strategy judgment can not occur in the attitude adjustment process of the automobile crane.

3. The whole gesture keeping process is automatically carried out without human interference, personal safety of workers is guaranteed, and working efficiency of the automobile crane is improved.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a flow chart of an automatic control method for maintaining the attitude of a chassis of an automobile crane in the loading operation according to the present invention;

FIG. 2 is a schematic structural characteristic diagram of the truck crane in an initial state provided by the automatic attitude keeping control method for the truck crane chassis in the loading operation according to the present invention;

FIG. 3 is a schematic diagram of the structural characteristics of the chassis provided by the automatic control method for maintaining the attitude of the chassis of the mobile crane in the loading operation.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides an automatic control method for maintaining the attitude of a chassis of an automobile crane in loading operation, which solves the defect that the automobile crane in the prior art can not maintain the attitude stability in real time in the loading operation process. The method for automatically controlling the attitude keeping of the chassis of the automobile crane in the loading operation uses the structural characteristics of the automobile crane shown in figure 2, and for the sake of brief description, the chassis 4 is equivalent to the chassis shown in figure 3In the plane, the amplitude cylinder 1 drives the crane boom 2 to ascend and descend at the equal angular speed, the slewing mechanism 3 drives the crane boom 2 to rotate at the equal angular speed, and the crane booms 2 at all levels are driven by the telescoping mechanisms to telescope at the equal speed; the effective lengths of all levels of the crane booms 2 are the same, the mass distribution is uniform, and the crane booms higher than the first level are overlapped and arranged in the next level of the crane boom; a displacement sensor for measuring the extension length of the second-stage crane boom is arranged between the second-stage crane boom and the first-stage crane boom, a rotation angle sensor for measuring the rotation angle of the crane boom 2 relative to the longitudinal symmetrical surface of the chassis 4 is arranged on the slewing mechanism 3, and a displacement sensor for measuring the extension length and equivalently calculating the amplitude variation angle of the crane boom 2 is arranged on the amplitude variation cylinder 1; supporting legs 9, numbered L in sequence₁～L₄The upper end of the supporting leg 9 is vertically inserted into a mounting hole of an outer extending beam on the chassis 4 at the same height, the lower end of the supporting leg is supported on the ground, the structural size and the maximum actuating stroke of each supporting leg 9 are completely the same, each supporting leg 9 is provided with a force sensor 5 for measuring the vertical load of the supporting leg 9 and a displacement sensor 6 for measuring the actuating amount of the supporting leg 9, and each force sensor 5 and each displacement sensor 6 are completely the same; the geometric center of the slewing mechanism 3 is positioned at the center position of the rectangle determined by the four supporting legs 9; a two-dimensional inclination angle sensor 7 is arranged at the central position of the slewing mechanism 3 and used for measuring a two-dimensional inclination angle of the chassis 4 relative to a horizontal plane; in an initial state, the chassis 4 is supported by the four support legs 9 to a tire suspension and geometric horizontal state, each support leg 9 bears uniform load, the crane boom 2 runs to the position of the crane weight 8, and the crane weight 8 is hung and installed but is not lifted off the ground.

The invention discloses an automatic control method for maintaining the posture of an automobile crane chassis in the loading operation, the control flow of which is shown in figure 1, and the method specifically comprises the following steps:

step 1, measuring the equivalent stiffness of each support leg 9, specifically: the 1 supporting leg 9 is driven to extend for vertical displacement and then is shortened to the original length, other supporting legs 9 except the supporting leg 9 are not moved in the period, and the load increment of the supporting leg 9 when the supporting leg 9 extends to a specific vertical displacement is measured by the displacement sensor 6 and the force sensor 5 on the supporting leg 9; dividing the load increment by the vertical displacement to obtain the equivalent stiffness of the leg 9; measuring the equivalent stiffness of the other 3 support legs 9 by adopting the same process; numbering according to leg 9, will etcEffective stiffness is denoted k_i，i＝1～4；

In the present embodiment, the specific vertical displacement is in a range of 1% to 5% of the maximum actuating stroke of the supporting leg 9.

Step 2, calculating the total weight and the mass center coordinate position of the automobile crane, specifically: the vertical load of each support leg 9 in the initial state is measured by the force sensor 5 and is marked as F_iI is 1-4; as shown in FIG. 2, a coordinate system is established with the geometric center of the upper surface of the revolving mechanism 3 as the origin of coordinates, the x, y and z axes of the coordinate system are respectively taken along the vertical, horizontal and vertical directions of the chassis 4, and the vertical and horizontal coordinates of each leg 9 are expressed as (x)_i，y_i) The positive directions of the moment and the inclination angle are judged according to the right-hand spiral rule; calculating the gross weight of the truck crane and longitudinal and transverse coordinates (x) of the mass center of the gross weight of the truck crane according to the measured vertical load of each supporting leg 9, the moment balance of the truck crane around the x and y axes and the force balance along the z axis_mc,y_mc) Is composed of

Step 3, calculating the hoisting weight, specifically: and driving the amplitude cylinder 1 to actuate to lift the hoisting weight 8 to the ground, measuring the vertical load of each supporting leg 9 by using the force sensor 5 again, and calculating the total weight G' of the automobile crane and the hoisting weight 8 so as to calculate the mass M of the hoisting weight 8.

Step 4, establishing a mass center coordinate parameterization model of the automobile crane and the hoisting weight whole body, specifically comprising the following steps: establishing the barycenter coordinate (x ') of the automobile crane and the lifting weight 8 as a whole according to the parameters of the automobile crane in the initial state, namely the initial extension length, the initial rotation angle and the initial amplitude variation angle of each level of crane arm 2 after the lifting weight hanging, the amplitude variation, the rotation and the stretching speed inherent to the automobile crane, and the mass and the size characteristics of each structure of the automobile crane'_mc,y′_mc) Parameterized model

In the formula, m_iI is 1 to n, n is the number of stages of the boom 2, l is the mass of the i-th boom 2_aAs is the length of the jib boom 2,to complete the initial amplitude variation angle of the crane boom 2 hung by the crane weight 8, the omega is measured by the displacement sensor on the amplitude variation cylinder_bFor the amplitude-variable angular velocity of the jib 2, t is positive when the jib 2 is lifted_bFor variable amplitude actuation time, /)_jIs the horizontal distance, m, from the rotating shaft of the crane arm 2 to the origin_bIs the mass of the counterweight 10, /)_bHorizontal distance of the weight 10 from the origin,/₀V is measured by a displacement sensor arranged between the second-stage crane arm and the first-stage crane arm to finish the initial extension length of each-stage crane arm 2 hung by the hoisting weight 8_sThe boom 2 is stretched at a positive speed t_sFor the telescopic time of the jib 2, #₀To complete the initial rotation angle of the crane boom 2 with the crane weight 8, the angle of rotation measured by the rotation angle sensor on the rotation mechanism 3 is omega_hIs the angular velocity, t, of the boom 2_hFor the time of the rotation, m_tAs chassis mass, x_tX-axis coordinate of chassis centroid, y_tThe balance weight is the whole of a cab, a swing mechanism fixed part and a chassis before combination, and the balance weight is the whole of a cab, a swing mechanism movable part and a rear balance weight block after combination.

Step 5, according to the equivalent rigidity k of each supporting leg 9_iVertical load F of each leg 9 in the initial state_iWeight and center of mass coordinate (x ') of the crane and hoisting weight 8 as a whole'_mc,y′_mc) A compensation action model of each supporting leg 9 is established according to the statics balance relation

In which b is the longitudinal span of four legs 9 and L is four legsTransverse span of leg 9, Δ z₁～Δz₄Are respectively the centroid of_mc,y_mc) Move to (x'_mc,y′_mc) The compensation action amounts of the four supporting legs 9 required for keeping the chassis 4 in a horizontal state correspond to the rising and falling actions of the supporting legs respectively.

Step 6, respectively measuring the inclination angles of the chassis 4 around the x axis and the y axis after the sling 8 lifts off the ground by using a two-dimensional inclination angle sensor 7; according to the formula betax_i-αy_iAnd calculating the compensation action amount of each supporting leg 9 required by leveling, wherein alpha and beta are the inclination angles of the chassis 4 around the x axis and the y axis in the current state respectively.

And 7, executing compensation actuation of the supporting legs 9 corresponding to lifting of the lifting weights 8, specifically: setting a roll threshold epsilon of the chassis 4_θRespectively calculating the absolute values of the inclination angles of the chassis 4 around the x and y axes; if the absolute values of both inclination angles are smaller than the roll threshold epsilon_θIf not, the compensating action of the supporting legs 9 corresponding to the lifting of the hoisting weight 8 is not executed, and the step 8 is directly executed, otherwise, the supporting legs 9 are controlled to synchronously act according to the proportional relation of the absolute values of the compensating action amounts of all the supporting legs until the compensating action amount is executed;

in the present embodiment, the roll threshold value ε_θThe range is 0.2-0.5 degrees.

Step 8, identifying the driver command, and estimating the compensation actuation data of the landing leg 9, specifically: monitoring and identifying amplitude variation, rotation and expansion commands of a driver for operating the upper device, and controlling the upper device to execute the corresponding action of the commands; setting a unit time interval, and obtaining the mass center coordinate (x ') of the whole automobile crane and the hoisting weight 8 in the step 4'_mc,y′_mc) The parameterized model budgets the coordinates of the integral mass center of the truck crane and the hoisting weight 8 corresponding to the instructions of the driver in m unit time intervals; respectively substituting the position coordinates of the mass center in the m unit time intervals into the compensation momentum model in the step 5, and calculating the compensation momentum of each supporting leg 9 in the m unit time intervals; the compensation action amount of the 1 st unit time interval is directly put into the first row of a matrix with the dimension of m multiplied by 4, the p-th unit time interval, p is more than or equal to 2, and the subsequent compensation actionThe compensation action amount data of the previous unit time interval is subtracted from the amount data respectively and is sequentially put into the p-th row of the m multiplied by 4 dimensional matrix to form a m multiplied by 4 dimensional compensation action amount matrix of the supporting leg 9; setting the execution times k to be 0;

in this embodiment, m is in the range of 2 to 10; the unit time interval is in the range of 1 second to 5 seconds.

Step 9, executing the upper mounting action and the compensation action of the supporting leg 9 at a unit time interval, specifically: and adding 1 to the execution times k, driving the amplitude variation cylinder 1, the swing mechanism 3 and the telescopic mechanism to execute the amplitude variation, the swing and the telescopic actions of the upper device at a unit time interval according to the amplitude variation, the swing and the telescopic instructions operated by the driver, and synchronously executing the compensation actuation of the supporting leg 9 at a unit time interval according to the data in the compensation actuation quantity matrix.

Step 10, respectively measuring the inclination angles of the chassis 4 around the x axis and the y axis by using a two-dimensional inclination angle sensor 7, and calculating the absolute values of the two inclination angles; if the absolute values of both inclination angles are smaller than the roll threshold epsilon_θAnd step 11 is executed, otherwise, the supporting legs 9 are manually adjusted to adjust the chassis 4 to a geometric horizontal state, each supporting leg 9 bears uniform load, step 1 is executed again, the set unit time interval is shortened, and the step 8 is executed.

Step 11, monitoring and identifying the amplitude variation, rotation, expansion and contraction instructions of the driver for operating the upper loader and the lowering hoisting instruction, specifically comprising the following steps:

if the driver operates the amplitude variation, rotation and expansion instructions of the upper device continuously, executing a step 9; if the driver operates the change of the amplitude, rotation and expansion commands of the upper device or the compensation actuation of the upper device and the supporting legs at m unit time intervals is finished, executing the step 8;

if the driver operates the lowering and hoisting instruction, the force sensors on the support legs measure vertical loads, when the total vertical load is recovered to the total weight G of the automobile crane from the total weight G' of the automobile crane and the hoisting weight, the two-dimensional inclination angle sensor is used for measuring the inclination angles of the bottom disc around the x axis and the y axis, and the absolute values of the two inclination angles are calculated; if both absolute values are smaller than the roll threshold epsilon_θThen no leg compensation is performedStep 12 is executed, otherwise, according to the formula β x_i-αy_iCalculating compensation acting amount of each supporting leg required by leveling, controlling the supporting legs to synchronously act according to the proportional relation of the absolute values of the compensation acting amount of each supporting leg until the compensation acting amount is executed, and executing the step 12;

if the driver instructs to stop, executing step 12;

step 12, stopping the loading action and the supporting leg compensation action, measuring the vertical load by the force sensors on the supporting legs, and executing step 8 if the total vertical load is the total weight G' of the automobile crane and the hoisting weight; if the total vertical load is reduced to the gross weight G of the automobile crane, the total vertical load is measured and calculated in real time until a new hoisting weight lifts off the ground, and the amplitude variation angle of the hoisting arm at the moment is read as the initial amplitude variation angleThe extension length is taken as the initial extension length l₀The angle of revolution being said initial angle of revolution psi₀Substituting the formula (2) and further executing the step 8;

and step 13, the driver forcibly turns off the attitude keeping automatic control or turns off the main power supply of the automobile crane, and the attitude keeping control is finished.

Finally, it should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.