A swing grading assistance control method, control system, and excavator

Abstract

The application discloses a kind of rotary land auxiliary control method, control system and excavator, control system includes controller, rotary platform, movable arm, bucket rod, bucket, movable arm cylinder, bucket rod cylinder, bucket cylinder, movable arm cylinder displacement sensor, bucket rod cylinder displacement sensor, bucket cylinder displacement sensor and rotary pressure sensor;Controller controls bucket tooth tip position and bucket angle by controlling movable arm cylinder length, bucket rod cylinder length and bucket cylinder length, realizes control bucket bottom surface and operation reference surface parallel.In the system, by the movement of movable arm, bucket rod, bucket is combined control, realizes control bucket bottom surface and operation reference surface always parallel, realizes fast rotary land, obtains good land effect.

Description

Technical Field

[0001] This invention relates to the field of excavator technology, and in particular to a slewing-leveling auxiliary control method, a control system, and an excavator. Background Technology

[0002] The existing semi-automatic leveling control scheme for excavators controls two or three of the boom, stick, and bucket to make the bottom of the bucket or the tip of the bucket teeth move along a set straight line, such as towards or away from the driver, to achieve the work of leveling the ground or repairing slopes.

[0003] However, in actual operation, in order to achieve better and faster leveling results, operators often use slewing to scoop material, thus achieving faster ground leveling. However, existing technical solutions only provide auxiliary control for the retraction and extension of working devices (such as boom and bucket), without auxiliary control for slewing leveling, especially without auxiliary control based on the magnitude of slewing pressure. This makes it difficult for operators to perform fast and efficient leveling operations, and also makes it difficult to achieve the desired leveling effect. Summary of the Invention

[0004] In order to overcome at least one of the defects mentioned above in the prior art, the present invention provides a rotary leveling auxiliary control method, which controls the bottom surface of the bucket to always be parallel to the working reference plane, so as to realize the rapid and efficient leveling operation of the working device (such as the boom and bucket) and obtain the desired leveling effect.

[0005] In order to overcome at least one of the defects of the prior art, the present invention provides a slewing leveling auxiliary control system. In this system, by combining the control of the movement of the boom, stick, and bucket, the bottom surface of the bucket is kept parallel to the working reference plane, thereby achieving rapid slewing leveling and obtaining good leveling effect.

[0006] In order to overcome at least one of the defects described in the prior art, the present invention provides an excavator that employs the aforementioned slewing and leveling auxiliary control system, enabling the excavator to quickly achieve slewing and leveling operations.

[0007] The technical solution adopted by this invention to solve its problem is:

[0008] A method for auxiliary control of slewing on level ground, characterized in that:

[0009] S1. Control the bucket posture and obtain the relative posture of the bucket and the working reference plane. First, control the bottom surface of the bucket to be parallel to the working reference plane.

[0010] S2. Obtain the swing pressure, and based on the swing pressure, control the distance between the bucket and the working reference surface. When the swing pressure is greater than the set pressure, control the bucket to rise, increase the distance between the bucket and the working reference surface, and then remove part of the material on the working reference surface until the swing pressure reaches the set pressure.

[0011] S3. Control the bucket posture for the second time and obtain the relative posture of the bucket and the working reference plane. Control the bottom surface of the bucket to be parallel to the working reference plane for the second time.

[0012] S4. Control the bucket to perform leveling work.

[0013] Furthermore, the bottom surface of the bucket is always higher than the reference surface.

[0014] Furthermore, during the bucket's ascent, the bucket's attitude is simultaneously controlled to ensure that the bottom surface of the bucket is parallel to the working reference plane.

[0015] A slewing-on-leveling-ground-assistance control system, wherein the control system performs control according to the aforementioned slewing-on-leveling-ground-assistance control method.

[0016] The control system includes a controller, a slewing platform, a boom, a stick, a bucket, a boom cylinder for driving the boom, a stick cylinder for driving the stick, a bucket cylinder for driving the bucket, a boom cylinder displacement sensor, a stick cylinder displacement sensor, a bucket cylinder displacement sensor, and a slewing pressure sensor mounted on the slewing platform.

[0017] The slewing pressure sensor acquires the slewing pressure and transmits the slewing pressure signal to the controller; the controller controls the distance between the bottom surface of the bucket and the working reference surface based on the magnitude of the slewing pressure.

[0018] The boom cylinder displacement sensor acquires the boom cylinder length and transmits the boom cylinder length to the controller. The stick cylinder displacement sensor acquires the stick cylinder length and transmits the stick cylinder length to the controller. The bucket cylinder displacement sensor acquires the bucket cylinder length and transmits the bucket cylinder length to the controller. The controller controls the bucket tooth tip position and bucket angle by controlling the boom cylinder length, stick cylinder length, and bucket cylinder length, thereby controlling the bottom surface of the bucket to be parallel to the working reference plane.

[0019] Furthermore, when the vehicle body is not tilted, the controller controls the bottom surface of the bucket to be parallel to the working plane.

[0020] Furthermore, the slewing leveling auxiliary control system also includes a body tilt sensor, which acquires the body tilt angle and transmits the body tilt angle to the controller. When the vehicle body is tilted, the controller controls the bottom surface of the bucket to be parallel to the working plane.

[0021] Furthermore, the controller includes a displacement calculation module, a displacement deviation comparison module, and an action judgment module.

[0022] Furthermore, the slewing leveling auxiliary control system also includes an operating device, a slewing solenoid valve for controlling the slewing of the slewing platform, a boom solenoid valve for controlling the lifting or lowering of the boom, a stick solenoid valve for controlling the opening or retraction of the stick, and a bucket solenoid valve for controlling the opening or retraction of the bucket.

[0023] Furthermore, the slewing leveling auxiliary control system also includes a boom position sensor mounted on the boom, a stick position sensor mounted on the stick, and a bucket position sensor mounted on the bucket. The boom position sensor acquires the boom angle, the stick position sensor acquires the stick angle, and the bucket position sensor acquires the stick angle. The controller controls the bucket tooth tip position and bucket angle based on the boom angle, stick angle, and bucket angle to achieve parallelism between the bottom surface of the bucket and the working reference plane.

[0024] An excavator includes the aforementioned slewing and leveling auxiliary control system.

[0025] In summary, the slewing-assisted control method for level ground provided by this invention has the following technical effects:

[0026] By controlling the relative posture of the bucket and the working reference plane, the bottom surface of the bucket is kept parallel to the working reference plane at all times, and the distance between the bottom surface of the bucket and the working reference plane is controlled according to the rotation pressure, so as to achieve rapid rotation and leveling.

[0027] In summary, the slewing-on-flat-ground auxiliary control system provided by this invention has the following technical effects:

[0028] By combining and controlling the movements of the boom, stick, and bucket, the bottom surface of the bucket is kept parallel to the working reference plane at all times, while the distance between the bottom surface of the bucket and the working reference plane is controlled, enabling rapid turning and leveling of the ground, and achieving good leveling results.

[0029] In summary, the excavator provided by the present invention has the following technical effects: the excavator adopts the aforementioned slewing and leveling auxiliary control system, which enables the excavator to quickly achieve slewing and leveling operations. Attached Figure Description

[0030] Figure 1This is a schematic diagram of the state of the excavator when it is performing a slewing leveling operation in the technical solution of this invention.

[0031] Figure 2 This is a schematic diagram of the excavator structure in the technical solution of the present invention, and a schematic diagram of the installation positions of each functional module on the excavator.

[0032] Figure 3 This is a block diagram of the slewing-leveling auxiliary control system in the technical solution of this invention.

[0033] Figure 4 This is a flowchart of the slewing-on-flat-ground auxiliary control method in the technical solution of the present invention.

[0034] Figure 5 This is an auxiliary diagram illustrating the principle of controlling the bottom surface of the bucket to be parallel to the working reference plane by means of the movement states of the boom, stick, and bucket when the vehicle body is in a non-tilted state in the technical solution of this invention.

[0035] Figure 6 This is an auxiliary diagram illustrating the principle of controlling the bottom surface of the bucket to be parallel to the working reference plane by means of the movement states of the boom, stick, and bucket when the vehicle body is tilted.

[0036] The meanings of the reference numerals in the attached figures are as follows:

[0037] 1. Excavator; 2. Material to be leveled; 101. Boom; 102. Stick; 103. Bucket; 104. Swing platform; 105. Boom cylinder; 106. Stick cylinder; 107. Bucket cylinder; 108. Controller; 109. Body tilt sensor; 110. Boom position sensor; 111. Stick position sensor; 112. Bucket position sensor; 113. Setting and guidance module; 114. Swing angle sensor; 115. Swing pressure sensor; 24. Control device; 25. Swing solenoid valve. Detailed Implementation

[0038] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0039] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0041] See Figure 1 and Figure 4 This invention discloses a method for auxiliary control of slewing on flat ground.

[0042] A method for auxiliary control of slewing on flat ground.

[0043] S1. Control the bucket posture and obtain the relative posture of the bucket and the working reference plane. First, control the bottom surface of the bucket to be parallel to the working reference plane.

[0044] S2. Obtain the swing pressure, and based on the swing pressure, control the distance between the bucket and the working reference surface. When the swing pressure is greater than the set pressure, control the bucket to rise, increase the distance between the bucket and the working reference surface, and then remove part of the material on the working reference surface until the swing pressure reaches the set pressure.

[0045] S3. Control the bucket posture for the second time and obtain the relative posture of the bucket and the working reference plane. Control the bottom surface of the bucket to be parallel to the working reference plane for the second time.

[0046] S4. Control the bucket to perform leveling work.

[0047] In actual operation, the operator first selects the automatic adjustment mode and enters the automatic control process of this slewing and leveling auxiliary control method.

[0048] The specific control process is as follows: Figure 4 As shown, firstly, in step S301, the operator performs a slewing and leveling operation. The operator can decide whether the slewing and leveling control method of this invention is needed based on the working conditions and their own situation. If needed, the operator selects to activate the function on the excavator's control panel display and sets the working reference plane for the ground to be leveled. The excavator's control panel display includes a setting and guidance module 113 for the operator to select and activate this automatic control system and automatic control method to achieve automatic control of the bucket tooth tip position and attitude.

[0049] Then, proceeding to steps S302 and S303, if the operator encounters material accumulation in the slewing direction during the leveling work of the rotary platform, preventing slewing, the operator can control the slewing pressure sensor to detect the slewing pressure. If the slewing pressure is too high, the control unit controls the working device to lift upwards, and then checks the slewing pressure again. If the slewing pressure is still too high, the control unit continues to control the working device to lift upwards until the slewing pressure drops to a reasonable value. This value allows the excavator to perform material removal work relatively quickly. This value can be set through experience or multiple trials. During the process of controlling the lifting of the working device, the control unit does not simply lift the boom, but controls the combined movement of the boom and bucket, adjusting the bucket angle as the working device lifts to ensure that the bottom surface of the bucket remains parallel to the reference plane.

[0050] Then, proceed to steps S304 and S305, where the operator operates the slewing mechanism to level the ground. During the slewing process, if the bucket bottom is not parallel to the reference plane, control the bucket's attitude to align it with the reference plane. If, during operation, the operator manipulates the boom or stick, causing the bucket bottom to become non-parallel to the reference plane, continue to control it to ensure parallelism. If, during operation, the vehicle tilts, causing the bucket bottom to become non-parallel to the reference plane, continue to control the boom, stick, and bucket attitude to align the bucket bottom with the reference plane.

[0051] Finally, proceeding to steps S306 and S307, after completing this round of slewing and leveling operations, since there is still material on the ground, the operator operates the slewing mechanism to return the bucket to the position where the ground needs to be leveled, and then begins a new round of slewing and leveling operations. It is worth noting that because the operator has set a reference plane, regardless of the operator's operation, the working device (bucket bottom) will not exceed the reference plane, and the bucket will not damage the reference plane. This not only reduces the operator's adjustment time and increases construction efficiency, but also achieves excellent construction results.

[0052] In this technical solution, during operation, the bottom surface of the bucket is always higher than the reference surface.

[0053] In this technical solution, the bucket posture is simultaneously controlled during the bucket's ascent, ensuring that the bottom surface of the bucket is parallel to the working reference plane.

[0054] like Figure 1 The diagram shows the leveling process of the excavator 1's bucket 103 on the working reference surface, where the material 2 is being leveled.

[0055] like Figure 2 and Figure 3As shown, a slewing-leveling auxiliary control system is provided, wherein the control system performs control according to the aforementioned slewing-leveling auxiliary control method.

[0056] The control system includes a controller 108, a slewing platform 104, a boom 101, a stick 102, a bucket 103, a boom cylinder 105 for driving the boom, a stick cylinder 106 for driving the stick, a bucket cylinder 107 for driving the bucket, a boom cylinder displacement sensor, a stick cylinder displacement sensor, a bucket cylinder displacement sensor, and a slewing pressure sensor 115 mounted on the slewing platform 104.

[0057] The slewing pressure sensor acquires the slewing pressure and transmits the slewing pressure signal to the controller. The controller controls the distance between the bottom surface of the bucket and the working reference surface based on the magnitude of the slewing pressure.

[0058] The boom cylinder displacement sensor acquires the boom cylinder length and transmits the boom cylinder length to the controller. The stick cylinder displacement sensor acquires the stick cylinder length and transmits the stick cylinder length to the controller. The bucket cylinder displacement sensor acquires the bucket cylinder length and transmits the bucket cylinder length to the controller. The controller controls the bucket tooth tip position and bucket angle by controlling the boom cylinder length, stick cylinder length, and bucket cylinder length, thereby controlling the bottom surface of the bucket to be parallel to the working reference plane.

[0059] In the above technical solution, whether the excavator body is tilted or not, the controller controls the bottom surface of the bucket to be parallel to the working plane.

[0060] The following will combine Figure 2 and Figure 5 As shown, when the vehicle body is not tilted, the control process and principle of controlling the position of the bucket teeth and the bucket angle by controlling the length of the boom cylinder, the stick cylinder and the bucket cylinder, thereby achieving the control of the bottom surface of the bucket to be parallel to the working reference plane are introduced and explained.

[0061] like Figure 5 As shown, the forward and inverse kinematics of the working device are solved in the boom coordinate system (X,Y) to obtain the mutual conversion relationship between the bucket tooth tip coordinates, joint rotation angles, and cylinder displacements.

[0062] Based on the displacement information obtained from the displacement sensors of each hydraulic cylinder, the pose of the bucket tooth tip is calculated.

[0063] Based on the lengths of the boom cylinder, stick cylinder, and bucket cylinder, determine the position of the bucket teeth and the bucket angle.

[0064] a. Through Figure 5The boom cylinder displacement sensor and stick cylinder displacement sensor shown measure the cylinder lengths of the boom and stick as λ1 and λ2, respectively. The joint angles of the boom and stick are calculated as θ1 and θ2 using the following formulas.

[0065]

[0066] Throughout the above calculations, the goal is always to ensure that the bottom surface of the bucket is aligned with the working reference surface.

[0067] In the above control process, by controlling the length of each cylinder, the cylinder length can be directly measured without converting the boom IMU and stick IMU into the boom cylinder length and stick cylinder length, reducing intermediate conversions and making the control more precise.

[0068] b. Through Figure 5 The bucket cylinder displacement sensor shown measures the length λ3 of the bucket cylinder, and the bucket joint angle θ3 is calculated using the following formula.

[0069]

[0070] θ3=π-∠BCK-∠KCJ-∠MCJ-∠MCD (Formula 4)

[0071] c. Determine the position of the bucket tooth tip based on the joint angle.

[0072] The bucket tip pose [x] is obtained through the DH method and matrix transformation. D y D ξ] T for:

[0073]

[0074] Where s1 = sinθ1, c1 = cosθ1, s 12 =sin(θ1+θ2), c 12 =cos(θ1+θ2), s 123 =sin(θ1+θ2+θ3), c 123 =cos(θ1+θ2+θ3).

[0075] The slewing and leveling auxiliary control system also includes a body tilt sensor 109, which acquires the body tilt angle and transmits the body tilt angle to the controller. When the vehicle body is tilted, the controller controls the bottom surface of the bucket to be parallel to the working plane.

[0076] The following will combine Figure 2 and Figure 6As shown, the process and principle of controlling the position of the bucket teeth and the bucket angle by controlling the length of the boom cylinder, the stick cylinder and the bucket cylinder when the vehicle body is tilted are introduced and explained.

[0077] By performing a coordinate transformation based on the vehicle's tilt angle to geodetic coordinates, the bottom surface of the bucket remains parallel to the reference plane even when the vehicle is tilted. This allows for construction operations to be performed relative to geodetic coordinates.

[0078] like Figure 6 As shown, if the tilt angle of the vehicle body tilt sensor is θ4, the formula in Formula 1 above can be used to obtain the result.

[0079]

[0080] Then, using the DH method and matrix transformation, the bucket tooth tip pose [x] is obtained by applying the above formula 5. D y D ξ] T .

[0081] In this technical solution, the controller includes a displacement calculation module, a displacement deviation comparison module, and an action judgment module. The displacement calculation module calculates the displacement of the boom, stick, and bucket; the deviation comparison module corrects the displacement of the boom, stick, and bucket; and the action judgment module corrects and controls the movement displacement of the boom, stick, and bucket.

[0082] In this technical solution, the slewing leveling auxiliary control system also includes a control device 24, a slewing solenoid valve 25 for controlling the slewing of the slewing platform, a boom solenoid valve for controlling the lifting or lowering of the boom, a stick solenoid valve for controlling the opening or retraction of the stick, and a bucket solenoid valve for controlling the opening or retraction of the bucket.

[0083] In this technical solution, the slewing leveling auxiliary control system further includes a boom position sensor 110 installed on the boom, a stick position sensor 111 installed on the stick, and a bucket position sensor 112 installed on the bucket. The boom position sensor acquires the boom angle, the stick position sensor acquires the stick angle, and the bucket position sensor acquires the stick angle. The controller controls the bucket tooth tip position and bucket angle based on the boom angle, stick angle, and bucket angle to achieve parallelism between the bottom surface of the bucket and the working reference plane.

[0084] In this control system, the bottom surface of the bucket is kept parallel to the working reference plane by controlling the movement of the boom, stick, and bucket. The angles of the boom, stick, and bucket obtained from position sensors can also be calculated. The calculation process is described below.

[0085] If any of the boom, stick, or bucket is replaced with an IMU (Inertial Measurement Unit) for monitoring, the angles of the boom, stick, and bucket can be converted into cylinder lengths based on the angles, and the angle of the bucket bottom relative to the reference plane can still be calculated.

[0086] a. Through Figure 2 and Figure 5 The boom IMU and stick IMU shown measure the joint angles of the boom and stick as θ1 and θ2, respectively. The boom cylinder length λ1 and stick cylinder length λ2 are calculated using the following formulas.

[0087]

[0088] b. Calculate the bucket joint angle based on the length of the bucket cylinder.

[0089] pass Figure 5 The bucket cylinder displacement sensor shown measures the length λ3 of the bucket cylinder, and the bucket joint angle θ3 is calculated according to (Formula 3) and (Formula 4).

[0090] c. Determine the position of the bucket tooth tip based on the joint angle.

[0091] The bucket tip pose [x yξ] is obtained according to Formula 5 using the DH method and matrix transformation. T .

[0092] Therefore, in summary, the slewing leveling auxiliary control system of the present invention achieves rapid slewing leveling by combining and controlling the movements of the boom, stick, and bucket, ensuring that the bottom surface of the bucket is always parallel to the working reference surface, and simultaneously controlling the distance between the bottom surface of the bucket and the working reference surface, thereby achieving good leveling effect.

[0093] In this technical solution, a rotation angle sensor 114 is also installed on the slewing platform. The rotation angle sensor 114 acquires the real-time angle of the slewing platform and obtains the motion angle of the slewing platform during the slewing process on flat ground.

[0094] This technical solution provides an excavator 1, which includes the aforementioned slewing and leveling auxiliary control system, enabling the excavator to quickly perform slewing and leveling operations.

[0095] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A method for auxiliary control of slewing on level ground, characterized in that: The system employs a slewing-leveling auxiliary control system, which includes a controller, a slewing platform, a boom, a stick, a bucket, a boom cylinder for driving the boom, a stick cylinder for driving the stick, a bucket cylinder for driving the bucket, a boom cylinder displacement sensor, a stick cylinder displacement sensor, a bucket cylinder displacement sensor, and a slewing pressure sensor mounted on the slewing platform. S1. Control the bucket posture and obtain the relative posture of the bucket and the working reference plane, and control the bottom surface of the bucket to be parallel to the working reference plane for the first time; wherein, the boom cylinder length is obtained through the boom cylinder displacement sensor and the boom cylinder length is transmitted to the controller, the stick cylinder length is obtained through the stick cylinder displacement sensor and the stick cylinder length is transmitted to the controller, the bucket cylinder length is obtained through the bucket cylinder displacement sensor and the bucket cylinder length is transmitted to the controller, the controller controls the bucket tooth tip position and bucket angle by controlling the boom cylinder length, stick cylinder length and bucket cylinder length, so as to control the bottom surface of the bucket to be parallel to the working reference plane; S2. Obtain the swing pressure, and based on the swing pressure, control the distance between the bucket and the working reference surface. When the swing pressure is greater than the set pressure, control the bucket to rise, increasing the distance between the bucket and the working reference surface, and then remove some material from the working reference surface until the swing pressure reaches the set pressure. The swing pressure is obtained by a swing pressure sensor installed on the swing platform and the swing pressure signal is transmitted to the controller. The controller controls the distance between the bottom surface of the bucket and the working reference surface based on the magnitude of the swing pressure. S3. Control the bucket posture for the second time and obtain the relative posture of the bucket and the working reference plane. Control the bottom surface of the bucket to be parallel to the working reference plane for the second time. The controller controls the length of the boom cylinder, the length of the stick cylinder and the length of the bucket cylinder to control the position of the bucket teeth and the bucket angle, so as to control the bottom surface of the bucket to be parallel to the working reference plane. S4. Control the bucket to perform leveling work.

2. The slewing-on-flat-ground auxiliary control method according to claim 1, characterized in that: The bottom surface of the bucket is always higher than the reference surface.

3. The slewing-on-flat-ground auxiliary control method according to claim 1, characterized in that: During the bucket's ascent, the bucket's attitude is simultaneously controlled to ensure that the bottom surface of the bucket is parallel to the working reference plane.

4. The slewing-on-flat-ground auxiliary control method according to claim 1, characterized in that, When the vehicle body is not tilted, the controller controls the bottom surface of the bucket to be parallel to the working reference plane.

5. The slewing-on-flat-ground auxiliary control method according to claim 1, characterized in that, The slewing leveling auxiliary control system also includes a body tilt sensor, which acquires the body tilt angle and transmits the body tilt angle to the controller. When the vehicle body is tilted, the controller controls the bottom surface of the bucket to be parallel to the working reference plane.

6. The slewing-on-flat-ground auxiliary control method according to claim 1, characterized in that, The controller includes a displacement calculation module, a displacement deviation comparison module, and an action judgment module.

7. The slewing-on-flat-ground auxiliary control method according to claim 1, characterized in that, The slewing leveling auxiliary control system also includes an operating device, a slewing solenoid valve for controlling the slewing of the slewing platform, a boom solenoid valve for controlling the lifting or lowering of the boom, a stick solenoid valve for controlling the opening or retraction of the stick, and a bucket solenoid valve for controlling the opening or retraction of the bucket.

8. The slewing-on-flat-ground auxiliary control method according to claim 1, characterized in that, The slewing leveling auxiliary control system also includes a boom position sensor mounted on the boom, a stick position sensor mounted on the stick, and a bucket position sensor mounted on the bucket. The boom position sensor acquires the boom angle, the stick position sensor acquires the stick angle, and the bucket position sensor acquires the stick angle. The controller controls the bucket tooth tip position and bucket angle based on the boom angle, stick angle, and bucket angle to achieve parallelism between the bottom surface of the bucket and the working reference plane.

9. An excavator, characterized in that, It includes the slewing-on-flat-ground auxiliary control method as described in any one of claims 1 to 8.

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