阅读说明：本技术 一种反铲液压挖掘机轨迹控制系统及轨迹规划方法 (Track control system and track planning method for backhoe hydraulic excavator ) 是由 史青录 王泽林 赵霖 于 2019-09-20 设计创作，主要内容包括：本发明提供了一种反铲液压挖掘机轨迹控制系统及轨迹规划方法,包括上位机、下位机、伸缩量传感器、压力传感器、驱动装置和无线传输模块。通过传感器采集动臂、斗杆、铲斗三组液压缸的长度传至上位机计算后得出液压挖掘机实时位姿,在上位机上以二维图像形式体现。在水平面和坡面挖掘工况下规划铲斗齿尖轨迹,经上位机计算后转换为三组油缸的实时长度和压力,通过与实际油缸长度和压力比较后发出控制信号,实现反铲液压挖掘机水平面或坡面的自动挖掘。该系统无需设计专用机型,可在任意机型上加装,可有效提高坡面挖掘和平整场地时的施工效率和质量、简化操作并降低施工成本。(the invention provides a track control system and a track planning method for a backhoe hydraulic excavator. The length of three groups of hydraulic cylinders including a movable arm, a bucket rod and a bucket is acquired by a sensor and is transmitted to an upper computer for calculation, and then the real-time pose of the hydraulic excavator is obtained, and the real-time pose is reflected in a two-dimensional image form on the upper computer. Planning the locus of the tooth tips of the bucket under the excavation working condition of the horizontal plane and the slope, converting the locus into the real-time length and pressure of three groups of oil cylinders after calculation by an upper computer, and sending a control signal after comparing the real-time length and pressure of the oil cylinders, thereby realizing the automatic excavation of the horizontal plane or the slope of the backhoe hydraulic excavator. The system does not need to design a special machine type, can be additionally arranged on any machine type, can effectively improve the construction efficiency and quality when the slope is excavated and the field is leveled, simplifies the operation and reduces the construction cost.)

1. The utility model provides a back hoe hydraulic shovel trajectory control system which characterized in that: comprises an upper computer (1), a lower computer (2), a telescopic quantity sensor (3), a pressure sensor (4) and a driving device (5);

The upper computer (1) is used for planning the track of the excavator, converting the track into an expected length value and a pressure value of the oil cylinder and transmitting the expected length value and the pressure value to the lower computer (2) in real time, displaying the position and the attitude of the excavator in real time, and receiving the real-time oil cylinder length information of the telescopic quantity sensor (3) and the real-time oil cylinder pressure information of the pressure sensor (4);

The lower computer (2) is used for receiving signals transmitted by the upper computer (1) and controlling the driving device (5) to act;

The telescopic quantity sensor (3) is a laser ranging sensor, is respectively arranged on the movable arm oil cylinder (6), the bucket rod oil cylinder (7) and the bucket oil cylinder (8), and is used for detecting the real-time lengths of the movable arm oil cylinder (6), the bucket rod oil cylinder (7) and the bucket oil cylinder (8) and transmitting the length values of the oil cylinders to the upper computer (1) in real time;

the pressure sensor (4) is used for monitoring the pressure of two cavities of the oil cylinder and transmitting the pressure value of the oil cylinder to the upper computer in real time;

the driving device (5) adopts an electro-hydraulic proportional valve, and the telescopic length, the required pressure and the flow of the hydraulic cylinder of the working device are controlled by controlling the size and the direction of an opening of the electro-hydraulic proportional valve.

2. the backhoe hydraulic excavator trajectory control system of claim 1, wherein: the signal transmission among the upper computer, the lower computer, the telescopic quantity sensor and the pressure sensor is carried out wireless transmission through a wireless transmission module (9).

3. The backhoe hydraulic excavator trajectory control system of claim 1, wherein: the laser ranging sensor comprises a laser transmitting and receiving device (10) and a reflecting block (11), wherein the laser transmitting and receiving device (10) is used for transmitting a laser signal to the reflecting block and receiving a reflected laser signal of the reflecting block, comparing the received reflected laser signal with the transmitted laser signal and converting the received reflected laser signal into the distance between a transmitting point and the reflecting point; the reflection block (11) is used for reflecting the laser beam.

4. the backhoe hydraulic excavator trajectory control system of claim 3, wherein: the laser emitting and receiving device (10) is arranged on the outer side of the middle section of the cylinder barrel of the oil cylinder, and the reflecting block (11) is arranged at the end head part of the piston rod far away from the oil cylinder; the length of the oil cylinder at any moment: l ═ l_min+s-s_minIn the formula I_minThe shortest length of the oil cylinder; s is the distance between the laser emitting and receiving device (10) and the reflecting block (11); s_minis the distance between the corresponding laser transmitting and receiving device (10) and the reflecting block (11) when the oil cylinder is in the shortest length.

5. The backhoe hydraulic excavator trajectory control system of claim 3, wherein: the laser ranging sensor is characterized in that a protective cover (12) is arranged on a laser emitting and receiving device (10) and a reflecting block (11) of the laser ranging sensor, and the protective cover stretches along with the stretching of the hydraulic cylinder.

6. the backhoe hydraulic excavator trajectory control system of claim 1, wherein: and the pressure sensor is arranged on an oil inlet and outlet way of the corresponding oil cylinder on the main control valve group.

7. a method for planning a track of a backhoe hydraulic excavator is characterized by comprising the following steps:

S1, importing parameters of the backhoe hydraulic excavator into the upper computer (1), drawing an excavator envelope graph by the upper computer (1), and simultaneously displaying the envelope graph in real time;

S2, inputting excavation parameters of the backhoe hydraulic excavator in the upper computer (1), wherein the excavation parameters comprise parameters of excavation layer number, layering thickness, plane inclination angle, excavation length, point taking distance and bucket bottom rear angle;

S3, detecting the lengths of the movable arm oil cylinder (6), the arm oil cylinder (7) and the bucket oil cylinder (8) through the telescopic quantity sensor (3) respectively, and transmitting length parameters to the upper computer (1); the pressure sensor (4) respectively detects the pressure of two cavities of the movable arm oil cylinder (6), the bucket rod oil cylinder (7) and the bucket oil cylinder (8) and transmits pressure parameters to the upper computer (1);

S4, the upper computer (1) analyzes and calculates the data in the S3 and displays the pose of the excavator working device in a two-dimensional image mode;

s5, the upper computer (1) calculates an excavation track according to the parameter ratio of S2 and S3, the excavation track is converted into the lengths of a movable arm oil cylinder (6), a bucket oil cylinder (7) and a bucket rod oil cylinder (8), the expansion and contraction amounts of the three groups of oil cylinders are determined by comparing the actual oil cylinder lengths, a command is transmitted to the lower computer (2) through the wireless transmission module (9), and the lower computer (2) controls the excavator working device to act through the control driving device (5);

S6, the excavator starts to excavate, the stretching amount sensor (3) collects the instantaneous lengths of the movable arm oil cylinder (6), the arm oil cylinder (7) and the bucket oil cylinder (8) and transmits the instantaneous lengths to the upper computer (1) in real time, the upper computer (1) determines the stretching amount of the oil cylinders according to real-time data, and the pose of the excavator is displayed in real time in a two-dimensional image mode.

8. the method of claim 7 for planning the trajectory of a backhoe hydraulic excavator, wherein: the pose of the S4 working device is expressed by a matrix as:

Wherein: the included angle between the connecting line of the hinged point of the movable arm and the machine body and the hinged point of the movable arm and the bucket rod and the stopping surface,Is the angle of the arm relative to the boom,the turning angle of the bucket relative to the bucket rod is defined as a, a is the horizontal distance from a hinge point of a movable arm and a machine body to a rotation center in a symmetrical plane of the working device, and b is the vertical distance from the hinge point of the movable arm and the machine body to a stopping surface; l₁the distance between the hinged point of the movable arm and the body and the hinged point of the movable arm and the bucket rod is l₂the distance between the hinged point of the movable arm and the bucket rod and the hinged point of the bucket rod and the bucket is l₃the distance between the hinged point of the bucket rod and the bucket tooth tip in the longitudinal symmetry center plane is defined as the distance;

The attitude angle of a bucket tooth cusp V point in a longitudinal symmetry central plane isOrder toThe position of the V point is represented by a matrix as:

9. The method of claim 7 for planning the trajectory of a backhoe hydraulic excavator, wherein: each point on the S5 digging track is represented by coordinates as:

wherein θ is a plane inclination angle, l is a digging length, n is a dot pitch,the coordinates of the starting point are mined.

10. The method of claim 7 for planning the trajectory of a backhoe hydraulic excavator, wherein: the lengths of three groups of hydraulic cylinders in the S6 are as follows:

Instantaneous length of boom cylinder:

Instantaneous length of the bucket rod hydraulic cylinder:

Instantaneous length of bucket cylinder:

wherein l_GNthe distance between the hinged point of the bucket oil cylinder and the bucket rod and the hinged point of the rocker arm and the bucket rod is l_MNThe hinged point of the bucket oil cylinder and the rocker arm is connected with the rocker armdistance between hinged point of bucket rod l_CFThe distance between the hinged point of the movable arm and the body and the hinged point of the movable arm and the bucket rod is l_EFThe distance between the hinged point of the bucket rod oil cylinder and the bucket rod and the hinged point of the movable arm and the bucket rod is set; angle FCB, angle CFD, angle EFQ are structural angles, which are fixed values;Is the angle of the arm relative to the boom,the rotation angle of the bucket rod relative to the movable arm; alpha is alpha₁₁Is a connecting line between a hinged point of the movable arm and the machine body and a hinged point of the movable arm oil cylinder and the machine body and x₀y₀Angle of plane, wherein the coordinate system fixed on the rotary table is o₀x₀y₀z₀the origin o of the arm coincides with the intersection point of the rotation center and the bottom surface of the turntable, y₀axis and z₀The axis being located in a longitudinal plane of symmetry of the working device, x in the initial state₀Axis, y₀Axis, z₀the axes are respectively parallel to the x axis and the y axis of the geodetic coordinate system;

θ₃＝2π-∠GNF-∠FNQ-∠MNH-∠HNK-∠KNQ，

Wherein, angle GNF, angle FNQ and angle MNH are structural angles and are fixed values,

wherein l_HNis the distance between the hinged point of the rocker arm and the connecting rod and the hinged point of the rocker arm and the bucket rod_HKis the distance between the hinged point of the rocker arm and the connecting rod and the hinged point of the bucket and the connecting rod_NQIs the distance between the hinged point of the rocker arm and the bucket rod and the hinged point of the bucket rod and the bucket_KQthe distance between the hinged point of the bucket and the connecting rod and the hinged point of the bucket rod and the bucket,

l_NKfor the variation values:

wherein the content of the first and second substances,Angle NQF and angle KQV are structural angles and are fixed values.

Technical Field

The invention relates to the field of a trajectory planning and remote intelligent control system under the working conditions of a horizontal plane and a slope surface excavation of a hydraulic excavator, in particular to a trajectory control system and a trajectory planning method of a backhoe hydraulic excavator.

background

The hydraulic excavator is used as an engineering machine with wide application and plays an irreplaceable role in various construction fields. The operation of the existing hydraulic excavator is mainly manual operation, an operator can well coordinate and complete the operation only when reaching a certain proficiency level, the construction quality and the construction efficiency are different from person to person, even some working environments can cause harm to human bodies, and the hydraulic excavator is not suitable for the field operation of people. Many factors can influence the construction efficiency and the construction precision of the excavator, so that the development of a high-efficiency, high-precision, intelligent and humanized hydraulic excavator becomes an urgent need of more and more users.

the hydraulic excavator is used for leveling field, digging slope and repairing slope, which is one of the important working conditions of the hydraulic excavator and also one of the important indexes for embodying the operation level of the driver and the performance of the whole excavator. However, at the current state of technology at home and abroad, when a hydraulic excavator is used for plane operation, a driver needs to operate a boom cylinder, an arm cylinder and a bucket cylinder at the same time, and the operation effect, namely the flatness of a field or a slope after excavation, mainly depends on the operation skill and proficiency of the driver and is also greatly related to the control precision of the excavator. This not only influences operation effect and efficiency, still causes driver's fatigue easily, also can influence the life and the security of complete machine simultaneously.

disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a track control system and a track planning method of a backhoe hydraulic excavator, which can automatically plan tracks and can be remotely controlled under the excavation working conditions of a horizontal plane and a slope with a set angle.

A track control system of a backhoe hydraulic excavator comprises an upper computer, a lower computer, a telescopic quantity sensor, a pressure sensor and a driving device;

the upper computer is used for planning the track of the excavator and converting the track into the expected length and pressure of the oil cylinder and transmitting the expected length and pressure to the lower computer in real time, displaying the pose of the excavator in real time and receiving the real-time oil cylinder length information of the telescopic quantity sensor and the real-time oil cylinder pressure information of the pressure sensor;

the lower computer is used for receiving signals transmitted by the upper computer and controlling the driving device to act;

the telescopic quantity sensor is a laser distance measuring sensor, is respectively arranged on the movable arm oil cylinder, the bucket rod oil cylinder and the bucket oil cylinder, and is used for detecting the real-time length of the hydraulic oil cylinders of the movable arm, the bucket rod and the bucket and transmitting the length value of the oil cylinders to an upper computer in real time;

the pressure sensor is used for monitoring the pressure of the two cavities of the oil cylinder and transmitting the pressure value of the oil cylinder to the upper computer in real time;

the driving device adopts an electro-hydraulic proportional valve, and the telescopic length, the required pressure and the flow of the hydraulic cylinder of the working device are controlled by controlling the size and the direction of an opening of the electro-hydraulic proportional valve.

And signal transmission among the upper computer, the lower computer, the telescopic quantity sensor and the pressure sensor is performed through wireless transmission modules. The wireless transmission module is respectively and electrically connected with the upper computer, the lower computer, the telescopic quantity sensor and the pressure sensor, and the wireless transmission module is arranged to be multiple.

The laser ranging sensor comprises a laser emitting and receiving device and a reflecting block, wherein the laser emitting device is used for emitting laser signals to the reflecting block and receiving reflected laser signals of the reflecting block, comparing the received reflected laser signals with the emitted laser signals and converting the received reflected laser signals into the distance between an emitting point and the reflecting point; the reflection block is used for reflecting the laser beam.

The laser transmitter and receiver is arranged on the outer side of the middle section of the cylinder barrel of the oil cylinder, and the reflecting block is arranged at the head of one end of the piston rod; the length of the oil cylinder at any moment: l ═ l_min+s-s_minin the formula I_minThe shortest length of the oil cylinder; s is the distance between the laser emitting and receiving device and the reflecting block; s_minThe distance between the corresponding laser emitting and receiving device and the reflecting block when the oil cylinder is in the shortest length.

The laser emission and receiver of the telescopic quantity sensor and the reflection block are provided with protective covers, and the protective covers stretch along with the stretching of the hydraulic cylinder. The protective cover comprises a fixed cover and a telescopic cover, the fixed cover is fixed on the cylinder body of the oil cylinder, and the telescopic cover is fixed on the telescopic rod of the oil cylinder; the telescopic cover is sleeved in the fixed cover ru.

furthermore, the pressure sensor is arranged on an oil inlet and outlet way of the corresponding oil cylinder on the main control valve group.

a method for planning a track of a backhoe hydraulic excavator specifically comprises the following steps:

s1, importing parameters of the backhoe hydraulic excavator into an upper computer, drawing an excavator envelope graph by the upper computer, and simultaneously displaying the envelope graph in real time;

s2, inputting excavation parameters of the backhoe hydraulic excavator in the upper computer, wherein the excavation parameters comprise excavation layer number, layering thickness, plane inclination angle, excavation length, point taking distance and bucket bottom back angle parameters;

s3, detecting the lengths of the boom cylinder, the arm cylinder and the bucket cylinder respectively through the telescopic quantity sensor, and transmitting length parameters to an upper computer; the pressure sensors respectively detect the pressure of two cavities of the movable arm oil cylinder, the bucket rod oil cylinder and the bucket oil cylinder and transmit pressure parameters to the upper computer;

S4, the upper computer analyzes and calculates the data in the S3 and displays the pose of the excavator working device in a two-dimensional image mode;

S5, the upper computer calculates a digging track according to the parameter ratio in S2 and S3, the digging track is converted into the lengths of a boom oil cylinder, a bucket oil cylinder and an arm oil cylinder, the stretching amount of the three groups of oil cylinders is determined by comparing the lengths with the actual oil cylinders, a command is transmitted to the lower computer through the wireless transmission module, and the lower computer controls the action of the excavator working device through the control driving device;

And S6, the excavator starts to excavate, the length of the movable arm oil cylinder, the arm oil cylinder and the bucket oil cylinder is collected by the telescopic quantity sensor and transmitted to the upper computer in real time, the upper computer determines the telescopic quantity of the oil cylinders according to real-time data, and the pose of the excavator is displayed in real time in a two-dimensional image mode.

further, the S4 work apparatus pose is represented by a matrix as:

Wherein: The included angle between the connecting line of the hinged point of the movable arm and the machine body and the hinged point of the movable arm and the bucket rod and the stopping surface,Is the angle of the arm relative to the boom,the turning angle of the bucket relative to the bucket rod is defined as a, a is the horizontal distance from a hinge point of a movable arm and a machine body to a rotation center in a symmetrical plane of the working device, and b is the vertical distance from the hinge point of the movable arm and the machine body to a stopping surface;

The attitude angle of a bucket tooth cusp V point in a longitudinal symmetry central plane isOrder tothe position of the V point is represented by a matrix as:

further, each point on the S5 digging track is represented by coordinates as:

wherein θ is a plane inclination angle, l is a digging length, n is a dot pitch,The coordinates of the digging starting point, namely the coordinates of the bucket tooth cusp point in the longitudinal symmetry center plane are obtained.

further, the lengths of the three groups of hydraulic cylinders in S6 are:

Instantaneous length of boom cylinder:

Instantaneous length of the bucket rod hydraulic cylinder:

Instantaneous length of bucket cylinder:

Wherein l_GNthe distance between the hinged point of the bucket oil cylinder and the bucket rod and the hinged point of the rocker arm and the bucket rod is l_MNthe distance between the hinged point of the bucket oil cylinder and the rocker arm and the hinged point of the rocker arm and the bucket rod is l_CFThe distance between the hinged point of the movable arm and the body and the hinged point of the movable arm and the bucket rod is l_EFThe distance between the hinged point of the bucket rod oil cylinder and the bucket rod and the hinged point of the movable arm and the bucket rod is set; angle FCB, angle CFD, angle EFQ are structural angles, which are fixed values;Is the angle of the arm relative to the boom,the rotation angle of the bucket rod relative to the movable arm; alpha is alpha₁₁Is a connecting line between a hinged point of the movable arm and the machine body and a hinged point of the movable arm oil cylinder and the machine body and x₀y₀angle of plane, wherein the coordinate system fixed on the rotary table is o₀x₀y₀z₀The origin o coincides with the intersection point of the rotation center and the bottom surface of the turntable, y₀Axis and z₀The axis being located in a longitudinal plane of symmetry of the working device, x in the initial state₀axis, y₀axis, z₀the axes are respectively parallel to the x axis and the y axis of the geodetic coordinate system;

θ₃＝2π-∠GNF-∠FNQ-∠MNH-∠HNK-∠KNQ，

wherein, angle GNF, angle FNQ and angle MNH are structural angles and are fixed values,

wherein l_HNIs the distance between the hinged point of the rocker arm and the connecting rod and the hinged point of the rocker arm and the bucket rod_HKis the distance between the hinged point of the rocker arm and the connecting rod and the hinged point of the bucket and the connecting rod_NQis the distance between the hinged point of the rocker arm and the bucket rod and the hinged point of the bucket rod and the bucket_KQthe distance between the hinged point of the bucket and the connecting rod and the hinged point of the bucket rod and the bucket,

l_NKfor the variation values:

Wherein the content of the first and second substances,angle NQF and angle KQV are structural angles and are fixed values.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a track control system and a track planning method for a backhoe hydraulic excavator, wherein the system does not need to design a special machine type, can be additionally installed on any machine type, only needs simple hardware transformation, and leads geometric parameters of the additionally installed machine type into an upper computer according to a required format; the length of the hydraulic cylinder is measured by adopting the laser ranging sensor, so that error amplification when the position of the tooth tip is calculated by using the angle sensor is avoided, and the calculation precision is higher; the remote control operation is adopted, so that the safety of operators can be protected in a dangerous working environment; the horizontal plane and slope surface excavation operation can be accurately and quickly completed, and operators are liberated from complex and complicated operations. The two-dimensional graph is adopted to display the pose, so that the method has the advantages of small data transmission amount, accuracy and quickness in display, low hardware requirement and cost saving, helps a driver to visually observe the pose of the working device which cannot be seen due to the blind sight area on a cab display, and can be used for controlling the pose of a target in the controller. The track planning method adopted by the invention considers the excavation resistance generated by excavation thickness factors to be overcome, reversely requires the pressure required to be provided by the three groups of oil cylinders, and considers the excavation force required to be exerted in the excavation process, namely, the movement position of the tooth point and the pose of the bucket are controlled, the excavation force generated by the tooth point is controlled, and meanwhile, the slope-repairing working condition that only the tooth point position is required and the excavation force is not required and the slope excavation working condition that the tooth point position and the excavation force are required to be controlled simultaneously are met.

Drawings

FIG. 1 is a schematic view of a backhoe hydraulic shovel trajectory control system provided in accordance with the present invention;

FIG. 2 is a schematic view of a telescoping amount sensor installation;

FIG. 3 is a relationship between the length measured by the telescopic amount sensor and the length of the hydraulic oil cylinder;

FIG. 4 is a real-time pose display screen of the excavator work device;

FIG. 5 is a simplified schematic of a work apparatus;

FIG. 6 is a schematic diagram of an excavator swing arm mechanism;

FIG. 7 is a schematic view of the geometry of the excavator bucket linkage;

FIG. 8 is a host computer software interface;

FIG. 9 is a plan-cut geometry diagram;

in the figure: the device comprises an upper computer 1, a lower computer 2, a telescopic quantity sensor 3, a pressure sensor 4, a driving device 5, a movable arm oil cylinder 6, an arm oil cylinder 7, a bucket oil cylinder 8, a wireless transmission module 9, a laser emitting and receiving device 10, a reflecting block 11 and a protective cover 12.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the track control system of the backhoe hydraulic excavator comprises an upper computer 1, a lower computer 2, a wireless transmission module 9, a stretching amount sensor 3, a pressure sensor 4 and a driving device 5; the upper computer 1 is used for planning the track of the excavator, converting the track into expected length and pressure of an oil cylinder and transmitting the expected length and pressure to the lower computer 2 in real time, displaying the pose of the excavator in real time, and receiving real-time oil cylinder length information of the telescopic quantity sensor 3 and real-time oil cylinder pressure information of the pressure sensor 4; the lower computer 2 is used for receiving the signal transmitted by the upper computer 1 and controlling the action of the driving device 5; the telescopic quantity sensor 3 is a laser distance measuring sensor, is respectively arranged on a movable arm oil cylinder 6, an arm oil cylinder 7 and a bucket oil cylinder 8, and is used for detecting the real-time length of the hydraulic oil cylinders of the movable arm, the arm and the bucket and transmitting the length value of the oil cylinders to the upper computer 1 in real time; the pressure sensor 4 is used for monitoring the pressure of two cavities of the oil cylinder and transmitting the pressure value of the oil cylinder to an upper computer in real time; the states of a movable arm, an arm and a bucket are controlled by controlling the telescopic operation of a movable arm oil cylinder, an arm oil cylinder and a bucket oil cylinder, and finally the position of the bucket and the position of the bucket tooth tip are controlled, so that the plane or slope excavation operation is carried out in real time; the driving device 5 adopts an electro-hydraulic proportional valve, and the telescopic length, the required pressure and the flow of the hydraulic cylinder of the working device are controlled by controlling the size and the direction of an opening of the electro-hydraulic proportional valve.

In this embodiment, signal transmission all carries out wireless transmission through wireless transmission module 9 between host computer 1, next machine 2, flexible volume sensor 3, pressure sensor 4, wireless transmission module 9 respectively with host computer 1, next machine 2, flexible volume sensor 3, pressure sensor 4 electric connection, wireless transmission module 9 sets up to a plurality ofly, sets up respectively in the similar position of host computer 1, next machine 2, flexible volume sensor 3, pressure sensor 4.

And a group of laser ranging sensors are arranged on each group of oil cylinders to measure the real-time length of the oil cylinders. The structure principle of the laser range finder is shown in figure 2, and the laser range finderthe sensor comprises a laser transmitting and receiving device 10 and a reflecting block 11, wherein the laser transmitting and receiving device 10 is used for transmitting a laser signal to the reflecting block and receiving the reflected laser signal of the reflecting block, comparing the received reflected laser signal with the transmitted laser signal and converting the result into the distance between a transmitting point and the reflecting point, and then transmitting data to the upper computer 1; the reflection block 11 is used for reflecting the laser beam. The laser transmitter and receiver 10 is arranged on the outer side of the middle section of the cylinder barrel of the oil cylinder, and the reflecting block 11 is arranged at the head of one end of the piston rod; the length of the oil cylinder at any moment: l ═ l_min+s-s_minin the formula I_minThe shortest length of the oil cylinder; s is the distance between the laser transmitter and receiver 10 and the reflector block 11; s_minis the distance between the corresponding laser emitting and receiving device 10 and the reflecting block 11 when the oil cylinder is in the shortest length. The distance measuring precision of the laser distance measuring instrument is high and can reach 1mm level, and the operation requirement of the excavator can be met. The laser range finder has short response time which can reach 50Hz, compact appearance, easy installation, bus interface and easy integration into a field bus.

As shown in fig. 3, the laser transmitter/receiver 10 and the reflection block 11 of the expansion/contraction amount sensor are provided with a protective cover 12, and the protective cover 12 expands and contracts as the hydraulic cylinder expands and contracts. The protective cover 12 comprises a fixed cover and a telescopic cover, the fixed cover is fixed on the cylinder body of the oil cylinder, and the telescopic cover is fixed on the telescopic rod of the oil cylinder; the telescopic cover is sleeved in the fixed cover.

In this embodiment, the pressure sensor 4 is installed on an oil inlet and outlet path of a corresponding oil cylinder on the main control valve group. And a group of pressure sensors are arranged on each group of oil cylinders to measure the pressure of the inlet and the outlet of the oil cylinder and feed the pressure back to the upper computer 1, and the components can be arranged on the corresponding oil inlet and outlet paths of the oil cylinders on the main control valve group. The pressure of the oil inlet cavity of the oil cylinder depends on the external load; the pressure in the oil outlet chamber depends on two conditions: when the oil inlet pressure is used for overcoming external load, the oil outlet cavity is directly communicated with the oil tank, and the oil outlet resistance is the oil return resistance which is mainly limited by the on-way loss and the local loss during oil return; when the oil outlet cavity and the oil return resistance are needed to overcome the external load, the pressure of the oil outlet cavity needs to be adjusted by a back pressure valve, and the back pressure valve needs to be adjusted to provide necessary oil return pressure or resistance to balance the external load or meet the external load requirement. Therefore, a pressure sensor 4 and a back pressure valve are required to be arranged on the oil inlet path and the oil return path of each oil cylinder so as to adjust the pressure of the oil inlet path and the oil outlet path of the oil cylinder in real time. In this embodiment, the existing voltage regulation loop technology is adopted.

The real-time display of the pose of the working device is realized as follows: firstly, various parameters of the backhoe hydraulic excavator are input into an upper computer 1, the outline and the excavating envelope graph of the excavator are drawn, the lengths of a movable arm oil cylinder 6, a bucket rod oil cylinder 7 and a bucket oil cylinder 8 are detected through a telescopic quantity sensor 3 and then are transmitted to the upper computer through a wireless transmission module, a processor in the upper computer 1 analyzes and calculates to obtain the pose of an excavator working device, and the pose of the excavator working device is displayed in real time, and if the pose of the excavator working device is displayed in real time, a picture is shown in fig. 4.

the method for calculating the pose of the working device comprises the following steps:

Fig. 5 is a simplified schematic diagram of the working device, and the symbols and letter codes of the hinge points of the components are given as follows:

point A-the hinge point of the boom cylinder and the body;

Point B-the hinge point of the movable arm cylinder and the movable arm;

Point C-the hinge point of the boom and the body;

Point D-the hinge point of the bucket rod oil cylinder and the movable arm;

point E-the hinge point of the bucket rod cylinder and the bucket rod;

Point F-the point of articulation of the boom and the stick;

point G-the hinge point of the bucket cylinder and the bucket rod;

point M-the hinge point of the bucket cylinder and the rocker arm;

point H-the hinge point of the rocker arm and the connecting rod;

point N-the hinge point of the rocker arm and the dipper;

Point K-the point of articulation of the bucket with the link;

Point Q-the point of articulation of the dipper stick with the dipper;

point V-bucket tooth tip in the longitudinal center plane of symmetry;

a is the horizontal distance from the point C to the rotation center in the symmetrical plane of the working device;

b-the vertical distance from point C to the stopping surface;

the coordinate system is defined as follows:

Coordinate system o₀x₀y₀z₀-a coordinate system fixed to the turntable. The origin o coincides with the intersection point of the rotation center and the bottom surface of the turntable, y₀Axis, z₀the axis lies in the longitudinal symmetry plane of the working device. Initial state x₀Axis, y₀axis, z₀The axes are respectively parallel to the x axis and the y axis of the geodetic coordinate system;

coordinate system o₁x₁y₁z₁-a coordinate system fixed to the boom. Origin o₁Coincident with point C, y₁The axis is positive along the CF direction, and the coordinate system conforms to the right-hand rule;

coordinate system o₂x₂y₂z₂-a coordinate system fixed to the boom. Origin o₂Coincident with point F, y₂the axis is positive along the FQ direction, and the coordinate system conforms to the right-hand rule;

coordinate system o₃x₃y₃z₃-a coordinate system fixed to the boom. Origin o₃Coincident with point Q, y₃The axis is positive along the QV direction, and the coordinate system conforms to the right-hand rule;

The parameters of each rod piece determined by the D-H method are shown in Table 1:

TABLE 1D-H PARAMETERS

according to the D-H method, from the coordinate system o_i-1To o_i(i 1, 2, 3) around z_iRotation of the shaftThe transformation matrix of the angle is expressed by a modified 4 × 4 transformation matrix as:

from an original coordinate system O₀To the boom coordinate system O₁the 4 × 4 transform matrix of (a) is expressed as:

from a coordinate system O₃the 4 x 4 transformation matrix to interdental space V is represented as:

according to the coordinate system transformation principle, the pose matrix of the tail end of the working device is as follows:

wherein: The included angle between the connecting line of the hinged point of the movable arm and the machine body and the hinged point of the movable arm and the bucket rod and the stopping surface,Is the angle of the arm relative to the boom,the rotation angle of the bucket relative to the bucket rod;

obviously, the attitude angle of the V point isorder toThe position of the V point is represented by a matrix as:

wherein the cornerThe determination method of (2) is as follows:

(1) Boom movement analysis

as shown in fig. 6, in Δ AB 'C ≈ ACB' is:

wherein: l is₁Is the instantaneous length of the boom cylinder, /)_CAThe distance between the hinged point of the movable arm oil cylinder and the machine body and the hinged point of the movable arm and the machine body is l_CBThe distance is the distance between the hinged point of the movable arm oil cylinder and the movable arm and the hinged point of the movable arm and the machine body;

The included angle between the CF connecting line and the shutdown surface:

wherein: alpha is alpha₁₁connecting line with x for CA₀y₀The included angle of the plane; the angle FCB is a structural angle and is a fixed value;

(2) and (3) analyzing the movement of the bucket rod:

as shown in fig. 6, in Δ DEF ≈ DFE:

wherein: l is₂is the instantaneous length of the bucket rod hydraulic cylinder, /)_CFthe distance between the hinged point of the movable arm and the body and the hinged point of the movable arm and the bucket rod is l_EFThe distance between a hinged point of the bucket rod oil cylinder and the bucket rod and a hinged point of the movable arm and the bucket rod is set;

Rotation angle of the arm with respect to the boom:

Wherein the < CFD and the < EFQ are both structural angles and are fixed values;

(3) analyzing the movement of the bucket:

As shown in fig. 7, in Δ GMN ≈ GNM is:

In the formula: l is₃Instantaneous length of the bucket cylinder, /)_GNthe distance between the hinged point of the bucket oil cylinder and the bucket rod and the hinged point of the rocker arm and the bucket rod is l_MNThe distance between a hinged point of the bucket oil cylinder and the rocker arm and a hinged point of the rocker arm and the bucket rod is set;

Angle of rotation of bucket relative to stickfor the QV on the bucket relative to y₂The angle of rotation of the shaft.positive values indicate counterclockwise and negative values indicate clockwise.

wherein, the angle FQN and the angle KQV are both structural angles and are fixed values;

wherein l_NQthe distance between the hinged point of the rocker arm and the bucket rod and the hinged point of the bucket rod and the bucket,l_HNIs the distance between the hinged point of the rocker arm and the connecting rod and the hinged point of the rocker arm and the bucket rod_KQis the distance between the hinged point of the bucket and the connecting rod and the hinged point of the bucket rod and the bucket_HKThe distance is the distance between the hinged point of the rocker arm and the connecting rod and the hinged point of the bucket and the connecting rod;

Wherein, angle HNQ-MNQ-MNH-2 pi-theta₃-∠GNF-∠FNQ-∠MNH

Wherein, angle GNF, angle FNQ and angle MNH are structural angles and are fixed values;

So far, the relative rotation angles of the movable arm, the bucket rod and the bucket around the hinge points can be represented by the length change of the hydraulic cylinder.

in the present embodiment, automatic plane excavation is realized by: the upper computer 1 carries out track planning according to set excavation parameters, the track planning is converted into the lengths of a movable arm oil cylinder 6, a bucket oil cylinder 7 and an arm oil cylinder 8 after obtaining a result, the stretching amount of the three groups of oil cylinders is determined by comparing the length with the actual oil cylinder length, a command is transmitted to the lower computer 2 through the wireless transmission module 9, and the lower computer 2 controls the driving device 5 so as to control the action of the excavator working device.

Wherein the trajectory planning is implemented by: the upper computer is provided with parameters of the excavating layer number, the layering thickness, the plane inclination angle, the excavating length, the point taking distance and the excavating rear angle shown in fig. 8; wherein, the number of excavation layers is: the ratio of the total excavating thickness to the single-layer excavating thickness is defined under the condition of the required total excavating thickness and the set single-layer excavating thickness; layering thickness: in particular, h in fig. 2 indicates a single-layer excavation thickness set according to the actual capacity of the excavator under the requirement of the total excavation thickness; plane inclination angle: in particular, a slope angle 'alpha' in fig. 2 refers to an included angle between a slope surface formed after excavation and a horizontal plane; excavating length: in particular, t in fig. 2 refers to a set straight line distance traveled by a tooth tip during single-layer excavation or the length of an excavation slope; taking point spacing: calculating the average distance of discrete points on a slope formed by the tooth tips by upper computer software; bucket bottom relief angle: specifically, γ in fig. 2 refers to an angle between a straight line part at the front section of the bucket bottom and the excavation slope, and the angle is changed at the beginning stage of excavation at each floor due to the structural characteristics of the excavator working device and the position of the tooth tip, but is constant at the steady stage of excavation at each floor and is greater than or equal to a set value. Calculating the excavation track according to the known parameters, wherein the specific calculation method comprises the following steps:

The known plane inclination angle is theta, the excavation length is l, the point taking distance is n, and the coordinates of the excavation starting pointIs composed ofThe coordinates of each point on the plane excavation track are as follows:

according to coordinate points on the excavation trackThe rotation angles of the boom, arm, and bucket are obtained by the following method

As shown in fig. 9, knowing the included angle β between the plane inclination angle θ, the relief angle α, and the bucket edge, there is a geometric relationship:

the following steps are provided:

Solving equations to obtain

Then, the lengths of the three groups of hydraulic cylinders can be obtained by the following formula:

wherein, theta₃＝2π-∠GNF-∠FNQ-∠MNH-∠HNK-∠KNQ

Wherein, the angle GNF, the angle FNQ and the angle MNH are given values when structural parameters are known;

in this embodiment, the system specifically includes the following steps:

step 1, importing parameters of a backhoe hydraulic excavator into an upper computer 1, drawing an excavator envelope graph by the upper computer 1, and simultaneously displaying the envelope graph in real time;

step 2, importing parameters of the backhoe hydraulic excavator into an upper computer 1, drawing an excavator envelope graph by the upper computer 1, manually remotely controlling and adjusting an initial point of a working device of the backhoe hydraulic excavator, selecting a working mode to be manual remote control or automatic excavation, and entering step 3 or step 4;

and step 3, entering a manual remote control mode: the upper computer is manually operated to send an instruction, the instruction is transmitted to the lower computer through the wireless transmission module, and the driving device is used for controlling the excavator to work; the telescopic quantity sensor 3 collects the lengths of the movable arm oil cylinder 6, the bucket rod oil cylinder 7 and the bucket oil cylinder 8 and transmits the lengths to the upper computer in real time, and a processor in the upper computer processes the lengths in real time and displays the pose of the excavator in a two-dimensional image form in real time;

Step 4, entering an automatic excavation mode: the method comprises the following steps that excavating parameters of the backhoe hydraulic excavator are input into an upper computer 1, wherein the excavating parameters comprise excavating layer number, layering thickness, plane inclination angle, excavating length, point taking distance and bucket bottom relief angle parameters;

step 5, detecting the lengths of a movable arm oil cylinder 6, a bucket rod oil cylinder 7 and a bucket oil cylinder 8 through a telescopic quantity sensor 3 respectively, and transmitting length parameters to the upper computer 1; the pressure sensor 4 respectively detects the pressure of two cavities of the movable arm oil cylinder 6, the bucket rod oil cylinder 7 and the bucket oil cylinder 8, and transmits pressure parameters to the upper computer 1;

Step 6, the upper computer 1 analyzes and calculates the data in the step 5 to obtain the pose of the excavator working device, and displays the pose in real time;

7, the upper computer 1 calculates a digging track according to the parameter pairs in the steps 2 and 5, converts the digging track into the lengths of a movable arm oil cylinder 6, a bucket oil cylinder 7 and a bucket rod oil cylinder 8, determines the expansion amount of three groups of oil cylinders by comparing the lengths with the actual oil cylinders, transmits a command to the lower computer 2 through a wireless transmission module 9, and controls the action of the excavator working device by controlling the driving device 5 through the lower computer 2;

And 8, the excavator starts to excavate, the length of the movable arm oil cylinder 6, the length of the bucket rod oil cylinder 7 and the length of the bucket oil cylinder 8 are collected by the telescopic quantity sensor 3 and transmitted to the upper computer in real time, the upper computer determines the telescopic quantity of the oil cylinders according to real-time data, and the pose of the excavator is displayed in real time in a two-dimensional image mode.

In the embodiment, the adopted trajectory planning method considers the excavation resistance generated by excavation thickness factors to be overcome, when the working oil cylinder is in an active state, the pressure in the cylinder is determined by the pose of the working device and the size of the working load (excavation resistance) which are detected in real time, and the continuous oil supply of the working oil pump after the calculation by the upper computer, and then the pressure is fed back to the upper computer through the pressure sensor. When the working oil cylinder is in a passive state, the pressure in the cylinder depends on the force acting on the two ends of the oil cylinder in the current pose and the return oil backpressure. The acting force acting on the two ends of the oil cylinder is calculated by the upper computer in real time according to the working condition posture, the pressure required to be generated in the oil cylinder in a passive state is further calculated, and the pressure value is controlled by an adjustable throttle valve (a back pressure valve) on an oil return path of the oil cylinder and fed back to the upper computer for real-time control.

the specific control method comprises the following steps:

1) firstly, giving the thickness of an excavation layer;

2) Obtaining the excavating resistance generated by the tooth tip according to the material characteristics and the thickness of the excavating layer;

3) and (4) carrying out stress analysis on the working device according to the pose of the working device, and solving the stress at two ends of each oil cylinder. And converting the stress into the pressure in the oil cylinder cavity, wherein the pressure is used as the target value of the oil return pressure generated by an oil return back pressure valve during the active action or the passive action of the oil cylinder.

In addition, in order to ensure the safe operation of the hydraulic system, when the oil cylinder is in an active state, the value is compared with the system pressure and cannot be greater than the system pressure; when the oil cylinder is in a passive state, the value is compared with the locking pressure and cannot be greater than the set maximum locking pressure. No matter which state the oil cylinder is in, when the pressure required to be generated by the oil cylinder is greater than the system pressure or the maximum locking pressure, the tooth tip cannot be guaranteed to generate enough excavating force to overcome excavating resistance generated under the plane excavating working condition, the excavating thickness is selected to be too large, and the excavating thickness needs to be reset at the moment.

Although only the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art, and all changes are encompassed in the scope of the present invention.