Supporting leg control method, system and equipment of walking excavator and medium
By determining the outrigger angle and generating planning information in a walking excavator, and using the dynamic surface backstepping method to calculate the control signal, the problem of outrigger steering planning under non-parallel posture was solved, thus improving the safety and stability of the excavator.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-04-14
AI Technical Summary
Two-wheel drive walking excavators lack effective swing steering planning methods when the outriggers are in a non-parallel posture, which affects the safety and stability of the entire vehicle.
By determining whether the swing angles of the left and right front outriggers of the walking excavator are equal, the target outrigger is selected, swing planning information is generated, and the control signal is calculated using the dynamic surface backstepping method to control the target outrigger to swing reasonably so that the swing angles of the two outriggers are equal.
It enables reasonable swing control of the outriggers of the walking excavator in a non-parallel posture, improving operational safety and overall vehicle stability.
Smart Images
Figure CN121858835A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of engineering machinery technology, and in particular to a method, system, device and medium for controlling the outriggers of a walking excavator. Background Technology
[0002] Two-wheel drive walking excavators typically use outrigger swing to achieve steering. When the two outriggers are in a non-parallel posture of "inward (adjusted)" or "outward (i.e., extended)", they need to be adjusted to a parallel posture before synchronous swing steering can be performed. Otherwise, it will affect the safety and stability of the entire vehicle. Currently, there is a lack of swing steering planning methods that address the mixed state of parallel and non-parallel movements.
[0003] Therefore, how to reasonably control the swing of the outriggers of a walking excavator to improve the operational safety of the walking excavator is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention
[0004] The purpose of this application is to provide a method, system, device, and medium for controlling the outriggers of a walking excavator, which can reasonably control the swing of the outriggers of the walking excavator and improve the operational safety of the walking excavator.
[0005] To solve the above-mentioned technical problems, this application provides a method for controlling the outriggers of a walking excavator, the method comprising:
[0006] If a steering command is received, it is determined whether the swing angles of the left and right front outriggers of the walking excavator are equal.
[0007] If they are not equal, then the left front support leg or the right front support leg is selected as the target support leg;
[0008] Determine the swing angle difference between the left front support leg and the right front support leg, and generate swing planning information for the target support leg based on the swing angle difference;
[0009] The control signal is obtained by performing calculations based on the dynamic surface backstepping method according to the swing planning information;
[0010] The target outrigger is swung according to the control signal so that the swing angle of the left front outrigger is equal to that of the right front outrigger.
[0011] Optionally, swing planning information is generated for the target outrigger based on the swing angle difference, including:
[0012] Based on the swing angle difference, swing planning information that meets preset constraints is generated for the target outrigger;
[0013] The preset constraint is that the swing process corresponding to the swing planning information is sequentially a uniform acceleration swing stage, a uniform speed swing stage, and a uniform deceleration swing stage, and the acceleration value of the uniform acceleration swing stage is equal to the deceleration value of the uniform deceleration swing stage.
[0014] Optional, also includes:
[0015] The time point that satisfies the preset relationship Set as the end time of the uniformly accelerated oscillation phase;
[0016] Wherein, the preset relation is ; This indicates the swing angle of the target outrigger at the end of the uniformly decelerated swing phase. This indicates the swing angle of the target outrigger at the beginning of the uniformly accelerated swing phase. This represents the acceleration value during the uniformly accelerated oscillation phase;
[0017] Correspondingly, it also includes:
[0018] Calculate the starting time of the uniform oscillation phase using the time calculation formula. ;
[0019] The time calculation formula is as follows: .
[0020] Optionally, selecting either the left front outrigger or the right front outrigger as the target outrigger includes:
[0021] If the steering command is a left turn command and the left front outrigger and the right front outrigger are in an extended position, then the right front outrigger is selected as the target outrigger.
[0022] If the steering command is a left turn command and the left front outrigger and the right front outrigger are in an inward retraction state, then the left front outrigger is selected as the target outrigger.
[0023] If the steering command is a right turn command and the left front outrigger and the right front outrigger are in an extended state, then the left front outrigger is selected as the target outrigger.
[0024] If the steering command is a right turn command and the left front outrigger and the right front outrigger are in an inward retraction state, then the right front outrigger is selected as the target outrigger.
[0025] Optionally, before performing the calculation based on the dynamic surface backstepping method according to the oscillation planning information, the following steps are also included:
[0026] A dynamic model is established for the target outrigger;
[0027] The joint angular velocity of the target leg is determined using a high-order sliding mode differentiator, and the hydraulic cylinder external force of the target leg is determined using a disturbance observer.
[0028] The model parameters of the dynamic model, the joint angular velocity, and the external force of the hydraulic cylinder are used as the input quantities of the dynamic surface backstepping method.
[0029] Optionally, the joint angular velocity of the target outrigger is determined using a high-order sliding mode differentiator, and the hydraulic cylinder external force of the target outrigger is determined using a disturbance observer, including:
[0030] The joint angle of the target leg is detected, and the joint angle is input into the high-order sliding mode differentiator to obtain the joint angular velocity of the target leg;
[0031] The hydraulic cylinder driving force of the target outrigger is detected, and the joint angular velocity and the hydraulic cylinder driving force are input into the disturbance observer to obtain the external force of the hydraulic cylinder of the target outrigger.
[0032] Optionally, after selecting the left front outrigger or the right front outrigger as the target outrigger, the method further includes:
[0033] Lock the left front outrigger or the right front outrigger that was not selected as the target outrigger;
[0034] If the swing angles of the left front outrigger and the right front outrigger are equal, the locking of the left front outrigger or the right front outrigger is released, and the left front outrigger and the right front outrigger are controlled to swing synchronously according to the steering command.
[0035] This application also provides a leg control system for a walking excavator, the system comprising:
[0036] The judgment module is used to determine whether the swing angles of the left and right front outriggers of the walking excavator are equal if a steering command is received.
[0037] The outrigger selection module is used to select either the left front outrigger or the right front outrigger as the target outrigger if the swing angles of the left front outrigger and the right front outrigger are not equal.
[0038] The planning module is used to determine the swing angle difference between the left front support leg and the right front support leg, and generate swing planning information for the target support leg based on the swing angle difference.
[0039] The signal determination module is used to perform calculations based on the dynamic surface backstepping method according to the swing planning information to obtain the control signal;
[0040] The control module is used to control the swing of the target outrigger according to the control signal, so that the swing angle of the left front outrigger is equal to that of the right front outrigger.
[0041] This application also provides a storage medium storing a computer program thereon, which, when executed, implements the steps of the outrigger control method for the walking excavator described above.
[0042] This application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor, when calling the computer program in the memory, implements the steps of the outrigger control method of the walking excavator described above.
[0043] This application discloses a method for controlling the outriggers of a walking excavator. Upon receiving a steering command, this method compares the swing angles of the left and right front outriggers. If they are unequal, a target outrigger is selected from the left and right front outriggers. This application generates swing planning information for the target outrigger based on the difference in swing angles between the left and right front outriggers, and then calculates a control signal based on the dynamic surface backstepping method using the swing planning information. This application can control the target outrigger to swing according to the aforementioned control signal, so that the swing angles of the left and right front outriggers are equal. The above process utilizes the dynamic surface backstepping method to generate a control signal when the swing angles of the two outriggers are inconsistent, achieving reasonable swing control of the target outrigger and ensuring that the swing angles of the two outriggers are equal. Therefore, this application can perform reasonable swing control of the outriggers of a walking excavator, improving the operational safety of the walking excavator. This application also provides a walking excavator outrigger control system, a storage medium, and an electronic device, which have the above-mentioned beneficial effects, and will not be elaborated further here. Attached Figure Description
[0044] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0045] Figure 1 A flowchart illustrating a method for controlling the outriggers of a walking excavator, provided as an embodiment of this application;
[0046] Figure 2 A schematic diagram of the outstretched state of a walking excavator provided in an embodiment of this application;
[0047] Figure 3 A schematic diagram of the retracted state of a walking excavator provided in an embodiment of this application;
[0048] Figure 4 A schematic diagram of a walking excavator in parallel state provided for an embodiment of this application;
[0049] Figure 5 This is a schematic diagram illustrating the principle of selecting the first target outrigger when receiving a left turn command, provided in an embodiment of this application.
[0050] Figure 6 This is a schematic diagram illustrating the principle of selecting a second target outrigger when receiving a left turn command, provided in an embodiment of this application.
[0051] Figure 7 A schematic diagram illustrating the relationship between the angle of the left front outrigger and time, provided as an embodiment of this application;
[0052] Figure 8 A schematic diagram illustrating the relationship between the angular velocity and time of the left front outrigger, provided as an embodiment of this application;
[0053] Figure 9 A schematic diagram illustrating the relationship between the angle of the right front outrigger and time, provided as an embodiment of this application;
[0054] Figure 10 This is a schematic diagram illustrating the relationship between the angular velocity and time of the right front outrigger, provided as an embodiment of this application. Detailed Implementation
[0055] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0056] Please see below. Figure 1 , Figure 1 A flowchart illustrating a method for controlling the outriggers of a walking excavator, provided as an embodiment of this application.
[0057] Specific steps may include:
[0058] S101: If a steering command is received, determine whether the swing angles of the left and right front outriggers of the walking excavator are equal.
[0059] In this embodiment, the control module of a walking excavator can be applied. After receiving a steering command, the swing angles of the left and right front outriggers can be read. The swing angles are used to describe the rotational position of the outriggers relative to the machine's centerline or the ground.
[0060] In this embodiment, the swing angles of the left front outrigger and the right front outrigger can be compared. If they are equal, the left front outrigger and the right front outrigger can be rotated directly according to the steering command. If they are not equal, the relevant operations of S102 to S105 can be performed.
[0061] The outriggers of a walking excavator can be in three states: extended, retracted, and parallel. In the extended state, the intersection of the extended lines of the left and right front outriggers is in front of the walking excavator. In the retracted state, the intersection of the extended lines of the left and right front outriggers is behind the walking excavator. In the parallel state, the swing angles of the left and right front outriggers are equal.
[0062] Please see Figure 2 , Figure 3 and Figure 4 , Figure 2 This is a schematic diagram of the extended state of a walking excavator provided in an embodiment of this application. Figure 3 This is a schematic diagram of the retracted state of a walking excavator provided in an embodiment of this application. Figure 4 This is a schematic diagram of a walking excavator in parallel state, provided as an embodiment of this application.
[0063] S102: Select the left front support leg or the right front support leg as the target support leg.
[0064] This step is based on the premise that the swing angles of the left and right front outriggers are not equal. In this case, either the left or right front outrigger can be selected as the target outrigger. The target outrigger is the one that needs to swing independently.
[0065] Furthermore, after selecting the left front outrigger or the right front outrigger as the target outrigger, the left front outrigger or the right front outrigger that was not selected as the target outrigger can be locked. When the swing angles of the left front outrigger and the right front outrigger are equal, the lock on the left front outrigger or the right front outrigger can be released, and the left front outrigger and the right front outrigger can be controlled to swing synchronously according to the steering command.
[0066] S103: Determine the swing angle difference between the left front support leg and the right front support leg, and generate swing planning information for the target support leg based on the swing angle difference;
[0067] The swing angle difference reflects the inconsistency between the swing of the left and right front outriggers. Based on the swing angle difference, swing planning information can be generated for the target outrigger. The swing planning information includes parameters such as the angle and time that the target outrigger needs to adjust, ensuring that the target outrigger can adjust its swing angle according to the plan under the action of the control signal, so that the swing angles of the two outriggers are consistent.
[0068] S104: Calculate the control signal based on the dynamic surface backstepping method according to the swing planning information.
[0069] In this step, the swing planning information is input into the dynamic surface backstepping controller to obtain a control signal. This control signal can be the current input of the proportional valve. The magnitude of the current input determines the opening degree of the proportional valve, thereby controlling the flow rate of hydraulic oil and thus affecting the swing speed and direction of the target outrigger.
[0070] Specifically, this step can design a nonlinear robust controller using the dynamic surface backstepping method based on the swing planning information and the outrigger dynamics model, and calculate the current control signal for driving the electro-hydraulic proportional valve in real time to achieve high-precision trajectory tracking.
[0071] Dynamic Surface Control (DSC) is a backstepping control strategy that simplifies complex differentiation operations to the output of a filter by introducing a first-order filter.
[0072] S105: Control the swing of the target outrigger according to the control signal so that the swing angle of the left front outrigger is equal to that of the right front outrigger.
[0073] In this step, the current input of the proportional valve can be adjusted according to the control signal, thereby controlling the hydraulic oil flow and direction, and then adjusting the swing speed and direction of the target outrigger so that the swing angle of the left front outrigger is consistent with that of the right front outrigger.
[0074] In this embodiment, upon receiving a steering command, the swing angles of the left and right front outriggers of the walking excavator are compared. If they are not equal, a target outrigger is selected from the left and right front outriggers. This embodiment generates swing planning information for the target outrigger based on the difference in swing angles between the left and right front outriggers, and then calculates a control signal based on the dynamic surface backstepping method according to the swing planning information. This embodiment can control the target outrigger to swing according to the aforementioned control signal, so that the swing angles of the left and right front outriggers are equal. The above process utilizes the dynamic surface backstepping method to generate a control signal when the swing angles of the two outriggers are inconsistent, achieving reasonable swing control of the target outrigger and ensuring that the swing angles of the two outriggers are equal. Therefore, this embodiment can perform reasonable swing control of the outriggers of the walking excavator, improving the operational safety of the walking excavator.
[0075] As for Figure 1 A further description of the corresponding embodiment: the process of generating swing planning information for the target outrigger based on the swing angle difference includes: generating swing planning information for the target outrigger that meets preset constraints based on the swing angle difference.
[0076] The preset constraint is that the swing process corresponding to the swing planning information is sequentially a uniform acceleration swing stage, a uniform speed swing stage, and a uniform deceleration swing stage, and the acceleration value of the uniform acceleration swing stage is equal to the deceleration value of the uniform deceleration swing stage.
[0077] The starting time of the uniformly accelerated swing phase is the current time, the ending time of the uniformly accelerated swing phase is the starting time of the uniformly oscillating phase, the ending time of the uniformly oscillating phase is the starting time of the uniformly decelerated swing phase, and the angular velocity of the target outrigger at the ending time of the uniformly decelerated swing phase is 0.
[0078] As for Figure 1 In a further description of the corresponding embodiment, this embodiment can determine the swing angle of the target outrigger at the end of the uniform deceleration swing phase from the configuration file. The swing angle of the target outrigger at the beginning of the uniformly accelerated swing phase. and the acceleration value of the uniformly accelerated oscillation phase. Based on the above parameters, the end time of the uniformly accelerated oscillation phase and the start time of the uniform oscillation phase can be determined as follows:
[0079] The time point that satisfies the preset relationship Set as the end time of the uniformly accelerated oscillation phase;
[0080] Calculate the starting time of the uniform oscillation phase using the time calculation formula. ;
[0081] The above-mentioned preset relation is ;
[0082] The above time calculation formula is: .
[0083] As for Figure 1 A further description of the corresponding embodiment suggests that the left front outrigger or the right front outrigger can be selected as the target outrigger in the following manner:
[0084] If the steering command is a left turn command and the left front outrigger and the right front outrigger are in an outward-pointing state (i.e., an outward-pointing state), then the right front outrigger is selected as the target outrigger. See also... Figure 5 , Figure 5This is a schematic diagram illustrating the principle of selecting the first target outrigger when receiving a left turn command, as provided in an embodiment of this application. The diagram shows the left front outrigger L1, right front outrigger R1, left rear outrigger L2, and right rear outrigger R2. In this case, the right front outrigger R1 is selected as the target outrigger, and the dashed line indicates the position that the right front outrigger R1 needs to swing to. In this state, the initial state is an outward-pointing posture, and the left front outrigger needs to be swung to the left first. After the two legs are parallel, a synchronous left turn is then performed, which ensures the safety and stability of the entire vehicle during the swinging process.
[0085] If the steering command is a left turn command and the left front outrigger and the right front outrigger are in an inward-pointing position (i.e., inward-pointing), then the left front outrigger is selected as the target outrigger. See also... Figure 6 , Figure 6 This is a schematic diagram illustrating the principle of selecting a second target outrigger when receiving a left-turn command, as provided in an embodiment of this application. The diagram shows the left front outrigger L1, right front outrigger R1, left rear outrigger L2, and right rear outrigger R2. In this case, the left front outrigger L1 is selected as the target outrigger, and the dashed line indicates the position that the left front outrigger L1 needs to swing to. In this state, the initial state is an inward-pointing posture, requiring the left front outrigger to swing to the left first. After the two legs are parallel, a synchronous left turn is then performed, which ensures the safety and stability of the entire vehicle during the swinging process.
[0086] If the steering command is a right turn command and the left front outrigger and the right front outrigger are in an extended position, then the left front outrigger is selected as the target outrigger.
[0087] If the steering command is a right turn command and the left front outrigger and the right front outrigger are in an inward retraction state, then the right front outrigger is selected as the target outrigger.
[0088] As for Figure 1 In a further description of the corresponding embodiment, before performing the calculation based on the dynamic surface backstepping method according to the swing planning information, a dynamic model can be established for the target leg; the joint angular velocity of the target leg is determined using a high-order sliding mode differentiator, and the hydraulic cylinder external force of the target leg is determined using a disturbance observer; the model parameters of the dynamic model, the joint angular velocity, and the hydraulic cylinder external force are used as the input quantities of the dynamic surface backstepping method.
[0089] Furthermore, the process of determining the joint angular velocity of the target leg using a high-order sliding mode differentiator and determining the hydraulic cylinder external force of the target leg using a disturbance observer includes: detecting the joint angle of the target leg and inputting the joint angle into the high-order sliding mode differentiator to obtain the joint angular velocity of the target leg; detecting the hydraulic cylinder driving force of the target leg and inputting the joint angular velocity and the hydraulic cylinder driving force into the disturbance observer to obtain the hydraulic cylinder external force of the target leg.
[0090] The process described in the above embodiments is illustrated below through examples in practical applications.
[0091] Two-wheel drive walking excavators typically use outrigger swinging for steering. When the outriggers are in a non-parallel "inward" or "outward" position, they need to be adjusted to a parallel position before synchronous swinging steering; otherwise, the overall safety and stability of the vehicle will be affected. Currently, there is a lack of swinging steering planning methods for this mixed parallel and non-parallel state. Synchronous swinging steering of walking excavators requires the tires to overcome time-varying ground friction. For this non-matched uncertain disturbance system, commonly used engineering control methods such as PID (Proportional Integral Derivative) have insufficient tracking accuracy. This solution designs a swinging steering trajectory planning method for outriggers in a mixed parallel and non-parallel state, and also provides an external force estimation method, and implements swinging steering control based on the dynamic surface backstepping method.
[0092] To address the technical problems existing in the aforementioned related technologies, this embodiment provides a motion planning and control scheme for the swing steering of a walking excavator. Upon receiving a steering command, this scheme acquires the joint angles, cylinder driving forces, and joint torques of the swing outriggers. Based on the steering command and the synchronization state of the two swing outriggers, it plans the swing trajectory of the outriggers, establishes a dynamic model of the swing outriggers, and estimates the joint angular velocity and external force disturbances of the cylinders using a state observer combining a high-order sliding mode differentiator and a disturbance estimator. The current input of the proportional valve of the cylinder is calculated using a dynamic surface backstepping controller.
[0093] This embodiment provides a trajectory planning method for swinging outriggers in both non-parallel and parallel states; it also provides a state estimation method for joint angular velocity and hydraulic cylinder external force in outrigger swinging and turning scenarios, as well as dynamic surface backstepping synchronous control.
[0094] The motion planning and control schemes described above will be introduced in detail below:
[0095] Step 1: Obtain the joint angle, hydraulic cylinder driving force, and joint torque of the swing outrigger.
[0096] Specifically, the process of obtaining the joint angle of the swinging leg is described below.
[0097] Each outrigger contains two joints: pitch and oscillation. The following explanation uses a single outrigger model: By reading information from the built-in displacement sensor of the hydraulic cylinder, the conversion relationship between joint angles and cylinder displacement is obtained according to the cosine theorem of the mechanism.
[0098] , formula (1).
[0099] in, This represents the distance vector between the hinge points of the hydraulic cylinder. Indicates the joint angle of the supporting leg. It is the transformation matrix between cylinder displacement and joint angle. This represents matrix operation functions. Representing the real number field A 3D vector space. Each leg consists of two joints, denoted as joint 1 and joint 2. This indicates the conversion relationship between the displacement of cylinder 1 and the joint angle. This indicates the conversion relationship between the displacement of cylinder 2 and the joint angle.
[0100] This step can obtain the hydraulic cylinder driving force based on formula (2). :
[0101] , formula (2).
[0102] in, and Indicates the effective area of the two cavities; These are the pressures in the rodless chamber and the rod chamber, respectively, which are obtained by reading pressure sensors. This represents the effective area of the rodless cavity of joint 1. This represents the effective area of the rodless cavity in joint 2. This represents the effective area of the rod cavity in joint 1. This represents the effective area of the rod cavity in joint 2. Represents the real number field.
[0103] Joint torque of the swinging outrigger It can be obtained from the conversion relationship between the hydraulic cylinder driving force and the joint torque, as shown in formula (3):
[0104] , formula (3).
[0105] in, It is a matrix for converting joint force and cylinder output force. It is the hydraulic cylinder driving force obtained by formula (2). This indicates the conversion relationship between the joint torque and the cylinder force of joint 1. This indicates the conversion relationship between the joint torque and the cylinder force of joint 2.
[0106] Step 2: Based on the steering command and the synchronization status of the two swinging outriggers, plan the swing trajectory of the outriggers.
[0107] The aforementioned rotation commands include: synchronous left turn or synchronous right turn issued by the host computer. The synchronous states of the two swinging outriggers include three states: "inward turn", "outward turn", and "parallel".
[0108] This embodiment can achieve the planning of the outrigger's swing trajectory through linear programming with polynomial fitting: Please refer to... Figure 7 , Figure 8 , Figure 9 and Figure 10 .
[0109] Figure 7 This is a schematic diagram illustrating the relationship between the angle of the left front outrigger and time, provided in an embodiment of this application. The vertical axis represents the angle, and the horizontal axis represents the time. Figure 8 This is a schematic diagram illustrating the relationship between the angular velocity and time of the left front outrigger, as provided in an embodiment of this application. The vertical axis represents the angular velocity, and the horizontal axis represents the time. This indicates the starting moment of the uniform acceleration phase, at which angle θ is... ; This indicates the end time of the uniform acceleration phase, at which point the angle is... angular velocity is ; This indicates the midpoint of the uniform velocity phase; This represents the starting moment of the uniform deceleration phase, at which angle θ is... angular velocity is ; This indicates the end time of the uniform deceleration phase, at which point the angle is... ; , and This indicates the angle of the left front leg at various moments during the synchronized movement of the left and right front legs. This indicates the end point of the synchronized movement phase of the left and right front legs. The angle is represented as angular velocity at time The angle is represented as angular velocity at time.
[0110] Figure 9 This is a schematic diagram illustrating the relationship between the angle and time of the right front outrigger, provided as an embodiment of this application. The vertical axis represents the angle, and the horizontal axis represents the time. Figure 10 This is a schematic diagram illustrating the relationship between the angular velocity and time of the right front outrigger, provided in an embodiment of this application. The vertical axis represents the angular velocity, and the horizontal axis represents the time. Indicates the right foreleg is in The angle at time t, at which the angular velocity is 0; Indicates the right foreleg is in The angle at time t, at which the angular velocity is 0; Indicates the right foreleg is in The angle at time t, at which the angular velocity is ; Indicates the right foreleg is in The angle at time t, at which the angular velocity is ; Indicates the right foreleg is in The angle at time t, at which the angular velocity is 0.
[0111] In the trajectory planning process of a linear function fitted by a polynomial, uniform acceleration and uniform deceleration are symmetrical. The individual swing of the left leg and the synchronized swing of both legs are considered. The planning time for the individual swing of the left leg is... ,in During the uniform acceleration phase, During the uniform speed phase, During the uniform deceleration phase, At a moment when the two legs are approximately parallel, the planned velocity is zero. Afterward, the two legs swing synchronously, with a planned swing time of [time value missing]. The specific calculation steps for the parameters are as follows:
[0112] Midpoint of the left leg swing The calculation is as follows:
[0113] , formula (4);
[0114] in, The starting time for the left supporting leg to swing independently. The end time of the swing of the left leg alone.
[0115] The angle of the left supporting leg swinging alone at the midpoint The calculation is as follows:
[0116] , formula (5);
[0117] in, The starting angle for the left leg to swing independently. The termination angle of the swing of the left leg alone.
[0118] by The acceleration representing the time interval of uniform acceleration can be obtained as follows:
[0119] , formula (6);
[0120] in, The joint angles are at the beginning of the uniform velocity phase. The joint angle is at the midpoint of the time interval. This is the start time of the uniform velocity phase. This is the intermediate moment.
[0121] Angle at the end of the uniform acceleration phase The calculation is as follows:
[0122] , formula (7);
[0123] in, The joint angle at the initial moment. For the acceleration during the uniform acceleration phase, This refers to the time of the uniform acceleration phase.
[0124] , formula (8);
[0125] In the formula, It is the middle of the overall planning process, the overall planning time. Half of it.
[0126] By combining equations (5) to (8), we can obtain:
[0127] , formula (9);
[0128] Based on the formula above, since the part inside the square root is greater than or equal to 0, the acceleration limit for the fitting segment is:
[0129] , formula (10);
[0130] Based on the starting angle and termination angle and preset acceleration Determine the time The acceleration time is determined according to formula (9). Once the time for each stage is determined, the joint angles at each moment are obtained based on the displacement formulas for uniform acceleration, uniform speed, and uniform deceleration, thus completing the trajectory planning of the outrigger. This indicates the maximum acceleration value of the walking excavator.
[0131] Step 3: Establish a dynamic model of the swing outrigger. Based on a state observer combining a high-order sliding mode differentiator and a disturbance estimator, estimate the joint angular velocity and the external force disturbance of the hydraulic cylinder. Calculate the current input of the proportional valve of the hydraulic cylinder using a dynamic surface backstepping controller.
[0132] The sub-steps of step 3 above include steps 3.1, 3.2, and 3.3, which are described below:
[0133] Step 3.1: Establish the dynamic model of the steering outrigger and perform the corresponding calculations.
[0134] The walking excavator in this design has two steering outriggers, the right front outrigger and the left front outrigger, which have two degrees of freedom: pitch and yaw. Steering control only involves the yaw degree of freedom.
[0135] The structural dynamics model of the outrigger can be described as follows:
[0136] , formula (11);
[0137] in, These are joint rotation angle, angular velocity, and acceleration. Represents the inertial force matrix. Represents the Coriolis force and centrifugal force matrices. Represents the gravity vector. Let the joint friction force vector be... This is the output torque vector for the joint. The joint torque represents the mapping of external environmental forces. ,in, This is the transpose of the joint Jacobian matrix. The force exerted by the ground on the tire is a three-dimensional external force. , and Represents the real number field.
[0138] The joint angle, angular velocity, and hydraulic cylinder driving force are used as state variables in sequence. , and , express The first derivative, express The first derivative, express The first derivative of , the state equation can be expressed as:
[0139] , formula (12).
[0140] in, This represents external force and modeling error. This represents the modeling error of the dynamics. This represents the unmodeled error in hydraulic dynamics. This represents the modeling error of the hydraulic dynamics of joint 1. This represents the modeling error of the hydraulic dynamics of joint 2. Indicates transpose. , , and Represents a diagonal matrix. and express diagonal elements, and express The diagonal elements. The Jacobian matrix representing the joint velocity and cylinder velocity. This represents the conversion matrix between joint force and cylinder output force.
[0141] , ;
[0142] express diagonal elements, express The diagonal elements; The value can be 1 or 2.
[0143] This indicates the volume of fluid in the rodless cavity of the joint. This indicates the volume of oil in the joint's rod cavity; The value can be 1 or 2.
[0144] Indicates the effective area of the two cavities, parameters ,parameter , It is the bulk modulus of elasticity. It is the hydraulic coefficient.
[0145] parameter ;
[0146] parameter .
[0147] Indicates valve core displacement. This indicates the pressure in the rodless cavity of the joint. This indicates that there is pressure in the joint cavity; The value can be 1 or 2.
[0148] These are system pressure and return oil pressure, respectively, and preset functions. It can be represented as:
[0149] ;
[0150] Parameters in the computational dynamic model Used for subsequent state estimation and control variables The calculation.
[0151] Step 3.2: Estimate the joint angular velocity and the external force of the hydraulic cylinder based on the state estimation method combining a high-order sliding mode differentiator and a disturbance observer.
[0152] The higher-order sliding mode differentiator estimates the angular velocity, expressed as:
[0153] , formula (13);
[0154] in, , , , , and Indicates positive gain. , , , , and For preset coefficients, They are The estimated value, This represents the estimated acceleration. , , It is a sufficiently small positive number; The value can be 1 or 2, and the cyclic relationship is satisfied. , , The value can be 1, 2, or 3; and sgn represents a positive coefficient and sgn represents the sign function. , and They represent , and The first derivative.
[0155] The external force disturbance estimator is designed as follows:
[0156] , formula (14);
[0157] in, It is an auxiliary variable. It is a positive constant. Represents the inertial force matrix. This represents the joint angular velocity estimated using a higher-order sliding mode differentiator. It is a conversion matrix between joint torque and cylinder driving force. This refers to the driving force of the hydraulic cylinder; the superscript symbol indicates an estimate. Representation of Coriolis force and centrifugal force matrix The estimated value, Represents the gravity vector. Indicates the amount of disturbance The estimated value, This represents the estimated value of the joint friction force vector.
[0158] express The first derivative, express The first derivative.
[0159] The estimation method used in the above process can, within a finite time, estimate the angular velocity to converge to the neighborhood of the true angular velocity, and the estimated disturbance to converge to the true external force of the hydraulic cylinder. In this way, the unknowns in the dynamic model can be estimated and used for subsequent control algorithm design.
[0160] Step 3.3: Calculate the current input of the proportional valve based on the dynamic surface backstepping method controller.
[0161] Error between actual joint angle and desired joint angle Defined as:
[0162] , formula (15);
[0163] in, This refers to the actual joint angle. For the desired joint displacement, the error The derivative is:
[0164] , formula (16);
[0165] This represents the first derivative of the desired joint displacement.
[0166] First-order virtual control law Designed as follows:
[0167] , formula (17);
[0168] in, It is a positive diagonal matrix; a first-order filter is introduced, and the actual virtual input is... It can be written as:
[0169] , formula (18);
[0170] in, It is a time constant. For filter output, This is the filter input. The second-order error is defined as... Its derivative is:
[0171] , formula (19);
[0172] Virtual control rate Designed as follows:
[0173] , formula (20);
[0174] in, It is a positive diagonal matrix gain. Represents the gravity vector The estimated value, The filtered signal is represented as:
[0175] , formula (21);
[0176] in, It is a time constant. Indicates the filter output. This is the filter input. Tracking error. Defined as:
[0177] , formula (22);
[0178] The dynamic equation can be expressed as:
[0179] , formula (23);
[0180] Proportional valve controls input current for:
[0181] , formula (24);
[0182] in, It is a positive diagonal gain matrix. express The estimated value, express The estimated value, express The estimated value, express The estimated value.
[0183] As can be seen, this embodiment proposes a swing steering planning method to address the mixed parallel and non-parallel states of the outriggers during swing steering of walking excavators, achieving smooth trajectory planning. Simultaneously, this embodiment combines a high-order sliding mode differentiator and a disturbance observer to provide a method for estimating the state of joint velocity and external forces. By using a dynamic surface backstepping method to track the planned trajectory, the trajectory tracking accuracy of synchronous outrigger swing is significantly improved.
[0184] In the above embodiments, the extended state observer method can also be used for external force estimation, and PID, sliding mode control and other methods can also be used to implement outrigger control.
[0185] In this embodiment, the walking excavator achieves synchronous steering by swinging its outriggers. There is a mixed state where the two swinging outriggers are parallel or non-parallel. This solution performs motion planning for the swinging outriggers, achieving smooth motion regardless of whether a single leg swings or both legs swing synchronously. The provided external force estimator can effectively estimate the swing resistance, and synchronous control is achieved based on the dynamic surface backstepping method, enabling high-precision synchronous swing control.
[0186] A leg control system for a walking excavator provided in this application embodiment includes:
[0187] The judgment module is used to determine whether the swing angles of the left and right front outriggers of the walking excavator are equal if a steering command is received.
[0188] The outrigger selection module is used to select either the left front outrigger or the right front outrigger as the target outrigger if the swing angles of the left front outrigger and the right front outrigger are not equal.
[0189] The planning module is used to determine the swing angle difference between the left front support leg and the right front support leg, and generate swing planning information for the target support leg based on the swing angle difference.
[0190] The signal determination module is used to perform calculations based on the dynamic surface backstepping method according to the swing planning information to obtain the control signal;
[0191] The control module is used to control the swing of the target outrigger according to the control signal, so that the swing angle of the left front outrigger is equal to that of the right front outrigger.
[0192] In this embodiment, upon receiving a steering command, the swing angles of the left and right front outriggers of the walking excavator are compared. If they are not equal, a target outrigger is selected from the left and right front outriggers. This embodiment generates swing planning information for the target outrigger based on the difference in swing angles between the left and right front outriggers, and then calculates a control signal based on the dynamic surface backstepping method according to the swing planning information. This embodiment can control the target outrigger to swing according to the aforementioned control signal, so that the swing angles of the left and right front outriggers are equal. The above process utilizes the dynamic surface backstepping method to generate a control signal when the swing angles of the two outriggers are inconsistent, achieving reasonable swing control of the target outrigger and ensuring that the swing angles of the two outriggers are equal. Therefore, this embodiment can perform reasonable swing control of the outriggers of the walking excavator, improving the operational safety of the walking excavator.
[0193] Furthermore, the planning module generates swing planning information for the target outrigger based on the swing angle difference, including: generating swing planning information for the target outrigger that meets preset constraints based on the swing angle difference;
[0194] The preset constraint is that the swing process corresponding to the swing planning information is sequentially a uniform acceleration swing stage, a uniform speed swing stage, and a uniform deceleration swing stage, and the acceleration value of the uniform acceleration swing stage is equal to the deceleration value of the uniform deceleration swing stage.
[0195] Furthermore, it also includes:
[0196] The end time determination module is used to determine the time points that satisfy the preset relationship. Set as the end time of the uniformly accelerated oscillation phase;
[0197] Wherein, the preset relation is ; This indicates the swing angle of the target outrigger at the end of the uniformly decelerated swing phase. This indicates the swing angle of the target outrigger at the beginning of the uniformly accelerated swing phase. This represents the acceleration value during the uniformly accelerated oscillation phase;
[0198] Correspondingly, it also includes:
[0199] The start time determination module is used to calculate the start time of the uniform oscillation phase according to the time calculation formula. ;
[0200] The time calculation formula is as follows: .
[0201] Furthermore, the process by which the outrigger selection module selects the left front outrigger or the right front outrigger as the target outrigger includes: if the steering command is a left turn command and the left front outrigger and the right front outrigger are in an extended state, then the right front outrigger is selected as the target outrigger; if the steering command is a left turn command and the left front outrigger and the right front outrigger are in an retracted state, then the left front outrigger is selected as the target outrigger; if the steering command is a right turn command and the left front outrigger and the right front outrigger are in an extended state, then the left front outrigger is selected as the target outrigger; if the steering command is a right turn command and the left front outrigger and the right front outrigger are in an retracted state, then the right front outrigger is selected as the target outrigger.
[0202] Furthermore, it also includes:
[0203] The parameter determination module is used to establish a dynamic model for the target outrigger before performing calculations based on the dynamic surface backstepping method according to the swing planning information; it is also used to determine the joint angular velocity of the target outrigger using a high-order sliding mode differentiator and to determine the hydraulic cylinder external force of the target outrigger using a disturbance observer; it is also used to use the model parameters of the dynamic model, the joint angular velocity, and the hydraulic cylinder external force as inputs to the dynamic surface backstepping method.
[0204] Furthermore, the parameter determination module uses a high-order sliding mode differentiator to determine the joint angular velocity of the target leg, and uses a disturbance observer to determine the hydraulic cylinder external force of the target leg. The process includes: detecting the joint angle of the target leg and inputting the joint angle into the high-order sliding mode differentiator to obtain the joint angular velocity of the target leg; detecting the hydraulic cylinder driving force of the target leg and inputting the joint angular velocity and the hydraulic cylinder driving force into the disturbance observer to obtain the hydraulic cylinder external force of the target leg.
[0205] Furthermore, it also includes:
[0206] The synchronization control module is used to lock the left front outrigger or the right front outrigger that is not selected as the target outrigger after selecting the left front outrigger or the right front outrigger as the target outrigger; it is also used to release the lock on the left front outrigger or the right front outrigger if the swing angles of the left front outrigger and the right front outrigger are equal, and control the left front outrigger and the right front outrigger to swing synchronously according to the steering command.
[0207] Since the embodiments of the system part correspond to the embodiments of the method part, please refer to the description of the embodiments of the method part for the embodiments of the system part, and they will not be repeated here.
[0208] This application also provides a storage medium on which a computer program is stored, which, when executed, can perform the steps provided in the above embodiments. The storage medium may include various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.
[0209] This application also provides an electronic device that may include a memory and a processor. The memory stores a computer program, and when the processor calls the computer program in the memory, it can implement the steps provided in the above embodiments. Of course, the electronic device may also include various network interfaces, power supplies, and other components.
[0210] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.
[0211] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
Claims
1. A method for controlling the outriggers of a walking excavator, characterized in that, include: If a steering command is received, it is determined whether the swing angles of the left and right front outriggers of the walking excavator are equal. If they are not equal, then the left front support leg or the right front support leg is selected as the target support leg; Determine the swing angle difference between the left front support leg and the right front support leg, and generate swing planning information for the target support leg based on the swing angle difference; The control signal is obtained by performing calculations based on the dynamic surface backstepping method according to the swing planning information; The target outrigger is swung according to the control signal so that the swing angle of the left front outrigger is equal to that of the right front outrigger.
2. The outrigger control method for a walking excavator according to claim 1, characterized in that, Based on the swing angle difference, swing planning information is generated for the target outrigger, including: Based on the swing angle difference, swing planning information that meets preset constraints is generated for the target outrigger; The preset constraint is that the swing process corresponding to the swing planning information is sequentially a uniform acceleration swing stage, a uniform speed swing stage, and a uniform deceleration swing stage, and the acceleration value of the uniform acceleration swing stage is equal to the deceleration value of the uniform deceleration swing stage.
3. The outrigger control method for a walking excavator according to claim 2, characterized in that, Also includes: The time point that satisfies the preset relationship Set as the end time of the uniformly accelerated oscillation phase; Wherein, the preset relation is ; This indicates the swing angle of the target outrigger at the end of the uniformly decelerated swing phase. This indicates the swing angle of the target outrigger at the beginning of the uniformly accelerated swing phase. This represents the acceleration value during the uniformly accelerated oscillation phase; Correspondingly, it also includes: Calculate the starting time of the uniform oscillation phase using the time calculation formula. ; The time calculation formula is as follows: .
4. The outrigger control method for a walking excavator according to claim 1, characterized in that, Selecting either the left front outrigger or the right front outrigger as the target outrigger includes: If the steering command is a left turn command and the left front outrigger and the right front outrigger are in an extended position, then the right front outrigger is selected as the target outrigger. If the steering command is a left turn command and the left front outrigger and the right front outrigger are in an inward retraction state, then the left front outrigger is selected as the target outrigger. If the steering command is a right turn command and the left front outrigger and the right front outrigger are in an extended state, then the left front outrigger is selected as the target outrigger. If the steering command is a right turn command and the left front outrigger and the right front outrigger are in an inward retraction state, then the right front outrigger is selected as the target outrigger.
5. The outrigger control method for a walking excavator according to claim 1, characterized in that, Before performing calculations based on the dynamic surface backstepping method using the oscillation planning information, the following steps are also included: A dynamic model is established for the target outrigger; The joint angular velocity of the target leg is determined using a high-order sliding mode differentiator, and the hydraulic cylinder external force of the target leg is determined using a disturbance observer. The model parameters of the dynamic model, the joint angular velocity, and the external force of the hydraulic cylinder are used as the input quantities of the dynamic surface backstepping method.
6. The outrigger control method for a walking excavator according to claim 5, characterized in that, The joint angular velocity of the target outrigger is determined using a high-order sliding mode differentiator, and the external force of the hydraulic cylinder of the target outrigger is determined using a disturbance observer, including: The joint angle of the target leg is detected, and the joint angle is input into the high-order sliding mode differentiator to obtain the joint angular velocity of the target leg; The hydraulic cylinder driving force of the target outrigger is detected, and the joint angular velocity and the hydraulic cylinder driving force are input into the disturbance observer to obtain the external force of the hydraulic cylinder of the target outrigger.
7. The outrigger control method for a walking excavator according to claim 1, characterized in that, After selecting the left front outrigger or the right front outrigger as the target outrigger, the method further includes: Lock the left front outrigger or the right front outrigger that was not selected as the target outrigger; If the swing angles of the left front outrigger and the right front outrigger are equal, the locking of the left front outrigger or the right front outrigger is released, and the left front outrigger and the right front outrigger are controlled to swing synchronously according to the steering command.
8. A leg control system for a walking excavator, characterized in that, include: The judgment module is used to determine whether the swing angles of the left and right front outriggers of the walking excavator are equal if a steering command is received. The outrigger selection module is used to select either the left front outrigger or the right front outrigger as the target outrigger if the swing angles of the left front outrigger and the right front outrigger are not equal. The planning module is used to determine the swing angle difference between the left front support leg and the right front support leg, and generate swing planning information for the target support leg based on the swing angle difference. The signal determination module is used to perform calculations based on the dynamic surface backstepping method according to the swing planning information to obtain the control signal; The control module is used to control the swing of the target outrigger according to the control signal, so that the swing angle of the left front outrigger is equal to that of the right front outrigger.
9. An electronic device, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program, and the processor, when calling the computer program in the memory, implements the steps of the outrigger control method of the walking excavator as described in any one of claims 1 to 7.
10. A storage medium, characterized in that, The storage medium stores computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the outrigger control method for a walking excavator as described in any one of claims 1 to 7.