CN113482076B - Motion control method, device and medium for rotary platform of unmanned excavator - Google Patents

Abstract

The invention discloses a motion control method, a device and a medium for a rotary platform of an unmanned excavator, wherein the motion control method, the device and the medium comprise the following steps: step 1: constructing a motion control system model of the excavator rotating platform; step 2: k in motion control system model of excavator rotating platform by recursive least square method_pAnd T, carrying out online identification; and step 3: based on the motion characteristics of the excavator rotary platform, the motion process of the excavator rotary platform is divided into stages to obtain the maximum control instruction input at each stage; and 4, step 4: and calibrating the maximum control instruction duration of each stage in an off-line manner, and inputting the maximum control instruction of each stage into a motion control system model of the rotary platform of the excavator in combination with the maximum control instruction of each stage to obtain the rotary speed of the rotary platform of each stage. Through the division of the motion process in stages, the rotary platform is subjected to refined motion control, the fact that the actual rotary angle is matched with the target angle is guaranteed, and the rotary platform can accurately and quickly reach the expected position during automatic excavation.

Description

Motion control method, device and medium for rotary platform of unmanned excavator

Technical Field

The invention belongs to the field of unmanned excavator control, and particularly relates to a motion control method, a motion control device and a motion control medium for a rotary platform of an unmanned excavator.

Background

In automatic control of the excavator, position information of a current target excavation point, included angle information of an excavation surface and an excavator base coordinate system and included angle information of an excavator bucket tangent plane and the excavation surface are generally obtained, an expected pose state of an excavator arm is obtained through calculation of a preset inverse kinematics model, a pose difference value of the current pose state and the expected pose state of the excavator arm is determined, a pose difference value signal is generated and sent to a controller, and therefore the controller controls the excavator arm to move to the expected pose state, and the excavator is low in speed and accuracy.

In the motion control system of the automatic excavator shown in fig. 1, an operating handle of the excavator is driven by two six-axis manipulators, control commands are sent from an unmanned excavating main controller to a manipulator controller, a servo motor drives the manipulator handle to be pushed, pressure oil output by a main pump enters a working oil way of a rotary motor through a rotary reversing valve to drive the rotary motor to rotate, and a working device and an upper rotary table rotate leftwards or rightwards. Due to the structural complexity of the control system of the excavator, the transfer function of the whole control system is too complex to be described by an accurate mathematical model.

In the rotation control process of the unmanned excavator, because the inertia of the excavator working device is large, the hydraulic driving device has strong nonlinear characteristics and obvious communication time delay exists, the rotation platform is often difficult to control to safely and quickly reach a target position. If the control instruction is too small, the rotation speed is slow, and the operation efficiency is low; if the control instruction is too large, the actual rotation angle is easy to exceed the target angle, so that the rotation platform cannot reach the designated position in the operation process and deviates from an excavation point or an earth unloading point.

Disclosure of Invention

The invention aims to provide a motion control method, a motion control device and a motion control medium for a rotary platform of an unmanned excavator, which aim to perform refined motion control on the rotary platform by dividing the motion process of the rotary platform, ensure that the actual rotary angle is consistent with the target angle and ensure that the excavator can accurately reach an excavation point or a soil unloading point.

The technical scheme provided by the invention is as follows:

on one hand, the motion control method of the rotary platform of the unmanned excavator comprises the following steps:

step 1: constructing a motion control system model of the excavator rotating platform;

wherein, K_pT is a time constant and tau is a time delay for representing the gain coefficient of the rotation angular speed;

and calculating the time delay from the moment when the control command starts to the moment when the revolution angular speed changes.

Input control command u_maxAnd monitoring the change of the rotation angle, and recording the time from the input of the control command to the change of the rotation angle, which is recorded as tau.

The motion control system model of the excavator rotating platform is essentially a transfer function between the excavator rotating speed and a control instruction variable;

step 2: k in motion control system model of excavator rotating platform by recursive least square method_pAnd T, carrying out online identification;

and step 3: based on the motion characteristics of the excavator rotary platform, the motion process of the excavator rotary platform is divided into stages to obtain the maximum control instruction input at each stage;

and 4, step 4: the maximum control instruction duration of each stage is calibrated off line, and the maximum control instruction of each stage is combined and input into a motion control system model of the rotary platform of the excavator to obtain the rotary speed of the rotary platform of each stage, so that the motion control of the rotary platform of the unmanned excavator is realized.

The excavator sets a control command to 0, enters a free rotation stage, an angle encoder detects an actual angle, feedback control is realized by fine adjustment of deviation of the actual angle and a calculated theoretical angle, and a feedback control command u' is input at the moment and calculated as follows:

u' (t) is a fine-tuned control command, err is a difference value between an angle measured by a sensor at the time t and a rotation speed integral calculation angle at each stage, and kp, Ti and Td are a proportional coefficient, an integral coefficient and a differential coefficient of the controller.

Further, based on the motion characteristics of the excavator rotary platform, the motion process of the excavator rotary platform is divided into 4 stages, and the maximum control instruction of each stage is u in sequence_max、3u_max/4、u_maxA/2, 0, wherein u_maxAnd the control instruction is displayed when the manipulator pushes the excavator operating handle to the limit position.

Through multistage deceleration, the vibration caused by sudden cancellation of a control command can be reduced, and a smaller control command can be output when the target angle is too small, so that the situation that the rotation speed is too large and the rotation speed cannot be effectively decelerated due to too large input control command in the first stage is prevented.

Further, the revolving speed of the revolving platform at each stage is obtained by calculating according to the following formula:

t_i＝t_i-1+Δt_i

wherein v is₀(t)＝0，t₀＝τ，t_iControl command stop input time, Δ t, representing the ith phase_iIndicating the duration of the control instruction, v, of the i-th phase_i(t) represents the revolving speed of the revolving platform at the ith stage, and u (i) represents the control command input at the ith stage.

Further, the control command duration, Δ t, of the 2 nd and 3 rd phases is determined off-line₂＝1s，Δt₃＝1s，t₀＝τ。

Under the current model, substituting the control instruction duration into a rotation speed formula can ensure that the speed can be reduced even at the maximum speed, the speed reduction lasts for a certain time, the stability is ensured, and the acceleration process duration can be calculated only if the deceleration process duration exists;

further, the accumulated target rotation angle of all stages can be obtained by integrating the rotation speed of each stage, the difference between the target rotation angle and the initial angle is obtained by utilizing, and the control instruction duration is solved by utilizing the free rotation ending in the last stage, namely the rotation speed is 0 at the last rotation moment;

wherein, t₁＝τ+Δt₁，t₂＝t₁+Δt₂，t₃＝t₂+Δt₃，t₄＝t₃+Δt₄；

Get v₄(t₄) When the value is approximately equal to 0, the free rotation is finished, and the free rotation time is obtained and is approximately delta t₄＝t₄-t₃＝T ln(|v₃(t₃)|)；

1) The delay time tau measured off-line, the duration of the control commands at of the second and third phases₂、Δt₃Found free wheeling time Δ t₄And the target rotation angle y is substituted into the rotation speed integral to solve the delta t₁A numerical solution of (c);

if Δ t₁Without numerical solution, the difference between the target rotation angle and the initial angle is too small, and the maximum rotation angle u does not need to be input in the first stage_maxI.e. Δ t₁＝0；

2) Will be Δ t ₁0, delay time τ measured off-line, and control command duration Δ t of the third stage₃Found free wheeling time Δ t₄And the target rotation angle y are substituted into the rotation speed integral to solve the control command 3u_maxDuration of/4 Δ t₂A numerical solution of (c);

if Δ t₂If no numerical solution exists, the difference between the target rotation angle and the initial angle is too small, and the maximum rotation angle 3u does not need to be input in the second stage_max/4, i.e. Δ t₂＝0；

3) Will be Δ t₁＝0，Δt₂Delay time measured off-line when 0Time τ, free rotation time Δ t obtained₄And the target rotation angle y is substituted into the rotation speed integral to solve the control command u_maxDuration of/2 Δ t₃A numerical solution of (c);

if Δ t₃If no numerical solution exists, the difference between the target gyration angle and the initial angle is too small, and the maximum gyration angle u does not need to be input in the third stage _max2, i.e. Δ t₃＝0。

Setting Δ t₁Firstly, acceleration is needed, but the acceleration time and the acceleration amount are unknown, and a target angle is needed to be input for solving;

calculated Δ t₁When there is no solution, because of the acceleration time Δ t₁When the value is 0, a control command u is input_maxWithout increasing the revolution speed in the stage (3 u)_maxThe/4 phase slew rate begins to increase but for a certain duration, the final slew angle will exceed the target angle. This is caused by the target angle being too small, and there is no need to input the control command u at this time_maxAnd (3) a stage of (a).

Further, K in a motion control system model of the excavator rotating platform by using a recursive least square method_pAnd T, performing online identification by the following specific process:

step A: constructing a rotation speed state space equation and determining a recursion form;

revolution speed state space equation:

converting the above equation into a vector form:

the recursive form of the estimate of θ is set as:

wherein v (k) is a revolution angular velocity at the time k,

is the vector of the speed and the control command at the moment K-1, v (K-1) is the revolution angular speed measured by the sensor at the moment K-1, u (K-1) is the control command input at the moment K-1, and theta is the vector containing the parameters T and K to be identified_pThe expression of (1);

and

estimated parameters at time k and time k-1, respectively, K (k) is a gain matrix, v^*(k) Is the angular velocity of the revolution measured by the sensor,

a predicted value of a turning speed v (k) at the time k based on the history data at the time k-1;

and B: setting k to 1, initial value P (0) of covariance matrix to 10000 × E, E is unit matrix, initial estimation value of parameter

Is (1, 0), lambda is a forgetting factor, and the value is 0.95;

and C: recording sensor measurement data u (k) and v (k);

step D: k (k) is calculated, and then P (k) and P (k) are calculated respectively

Step E: judging whether the parameter to be identified meets the following conditions, if soIf not, adding 1 to the sampling frequency K, and repeating the step C, and if so, outputting the parameter to be identified as T and K_pCompleting online identification of the current value;

in another aspect, a motion control apparatus of a swing platform of an unmanned excavator includes:

a system model construction unit: constructing a motion control system model of the excavator rotating platform based on a transfer function between the excavator rotating speed and a control instruction variable;

a system model parameter online identification unit: k in motion control system model of excavator rotating platform by recursive least square method_pAnd T, carrying out online identification;

a motion phase dividing unit: based on the motion characteristics of the excavator rotary platform, the motion process of the excavator rotary platform is divided into stages to obtain the maximum control instruction input at each stage;

revolution speed solving means: the maximum control instruction duration of each stage is calibrated and calculated off line, and the maximum control instruction of each stage is combined and input into a motion control system model of the rotary platform of the excavator to obtain the rotary speed of the rotary platform of each stage, so that the motion control of the rotary platform of the unmanned excavator is realized.

Further, the motion process dividing unit divides the motion process of the excavator rotary platform into 4 stages based on the motion characteristics of the excavator rotary platform, and the maximum control instruction of each stage is u in sequence_max、3u_max/4、u_maxA/2, 0, wherein u_maxAnd the control instruction is displayed when the manipulator pushes the excavator operating handle to the limit position.

Further, the revolving speed solving unit calculates the revolving speed of the revolving platform at each stage according to the following formula:

t_i＝t_i-1+Δt_i

wherein v is₀(t)＝0，t₀＝τ₁，t_iControl command stop input time, Δ t, representing the ith phase_iIndicating the duration of the control instruction, v, of the i-th phase_i(t) represents the revolving speed of the revolving platform at the ith stage, and u (i) represents the control command input at the ith stage.

Furthermore, the rotation speed solving unit determines the control command duration, Δ t, of the 2 nd and 3 rd phases off-line₂＝1s，Δt₃Obtaining the accumulated target rotation angle of all stages by integrating the rotation speed of each stage, obtaining the difference between the target rotation angle and the initial angle, and solving the control instruction duration by using the free rotation ending in the last stage, namely the rotation speed is 0 at the last rotation moment;

wherein, t₁＝τ+Δt₁，t₂＝t₁+Δt₂，t₃＝t₂+Δt₃，t₄＝t₃+Δt₄；

Get v₄(t₄) When the value is approximately equal to 0, the free rotation is finished, and the free rotation time is obtained and is approximately delta t₄＝t₄-t₃＝T ln(|v₃(t₃)|)；

1) The delay time tau measured off-line, the duration of the control commands at of the second and third phases₂、Δt₃Found free wheeling time Δ t₄And the target rotation angle y is substituted into the rotation speed integral to solve the delta t₁A numerical solution of (c);

if Δ t₁Without numerical solution, the difference between the target rotation angle and the initial angle is too largeSmall, in this case, the input of the maximum turning angle u in the first stage is not required_maxI.e. Δ t₁＝0；

2) Will be Δ t ₁0, delay time τ measured off-line, and control command duration Δ t of the third stage₃Found free wheeling time Δ t₄And the target rotation angle y are substituted into the rotation speed integral to solve the control command 3u_maxDuration of/4 Δ t₂A numerical solution of (c);

if Δ t₂If no numerical solution exists, the difference between the target rotation angle and the initial angle is too small, and the maximum rotation angle 3u does not need to be input in the second stage_max/4, i.e. Δ t₂＝0；

3) Will be Δ t₁＝0，Δt₂Free-wheeling time Δ t obtained by off-line measurement of delay time τ as 0₄And the target rotation angle y is substituted into the rotation speed integral to solve the control command u_maxDuration of/2 Δ t₃A numerical solution of (c);

if Δ t₃If no numerical solution exists, the difference between the target gyration angle and the initial angle is too small, and the maximum gyration angle u does not need to be input in the third stage _max2, i.e. Δ t₃＝0。

In yet another aspect, a computer storage medium includes a computer program that, when executed by a processing terminal, causes the processing terminal to execute the method for controlling the movement of an unmanned excavator rotating platform.

Advantageous effects

The technical scheme of the invention provides a motion control method, a device and a medium for a rotary platform of an unmanned excavator, which comprises the following steps: step 1: constructing a motion control system model of the excavator rotating platform; step 2: k in motion control system model of excavator rotating platform by recursive least square method_pAnd T, carrying out online identification; and step 3: based on the motion characteristics of the excavator rotary platform, the motion process of the excavator rotary platform is divided into stages to obtain the maximum control instruction input at each stage; and 4, step 4: calibrating the maximum control command duration of each stage off-lineAnd (3) combining the maximum control instructions of all the stages, inputting a motion control system model of the rotary platform of the excavator, and obtaining the rotary speed of the rotary platform of each stage, thereby realizing the motion control of the rotary platform of the unmanned excavator. Through the division of the motion process in stages, the rotary platform is subjected to refined motion control, the fact that the actual rotary angle is matched with the target angle is guaranteed, the rotary platform can accurately and quickly reach the expected position when the excavator excavates automatically, and the efficiency of automatic excavation is improved.

Drawings

FIG. 1 is an excavator motion control system;

FIG. 2 is a graph of angular velocity of the rotary platform movement versus control commands over time;

FIG. 3 is a schematic flow diagram of a process according to an embodiment of the present invention;

fig. 4 is a schematic diagram of the control principle of the method according to the embodiment of the invention.

Detailed Description

The invention will be further described with reference to the accompanying drawings and examples.

As shown in fig. 3, a method for controlling the movement of a revolving platform of an unmanned excavator includes:

step 1: constructing a motion control system model of the excavator rotating platform;

wherein, K_pT is a time constant and tau is a time delay for representing the gain coefficient of the rotation angular speed;

and calculating the time delay from the moment when the control command starts to the moment when the revolution angular speed changes.

Input control command u_maxAnd monitoring the change of the rotation angle, and recording the time from the input of the control command to the change of the rotation angle, which is recorded as tau.

The motion control system model of the excavator rotating platform is essentially a transfer function between the excavator rotating speed and a control instruction variable;

step 2: k in motion control system model of excavator rotating platform by recursive least square method_pAnd T, carrying out online identification;

k in motion control system model of excavator rotating platform by recursive least square method_pAnd T, performing online identification by the following specific process:

step A: constructing a rotation speed state space equation and determining a recursion form;

revolution speed state space equation:

converting the above equation into a vector form:

the recursive form of the estimate of θ is set as:

wherein v (k) is a revolution angular velocity at the time k,

is the vector of the speed and the control command at the moment K-1, v (K-1) is the revolution angular speed measured by the sensor at the moment K-1, u (K-1) is the control command input at the moment K-1, and theta is the vector containing the parameters T and K to be identified_pThe expression of (1);

and

estimated parameters at time k and time k-1, respectively, K (k) is a gain matrix, v^*(k) Is the angular velocity of the revolution measured by the sensor,

a predicted value of a turning speed v (k) at the time k based on the history data at the time k-1;

and B: setting k to 1, initial value P (0) of covariance matrix to 10000 × E, E is unit matrix, initial estimation value of parameter

Is (1, 0), lambda is a forgetting factor, and the value is 0.95;

and C: recording sensor measurement data u (k) and v (k);

step D: k (k) is calculated, and then P (k) and P (k) are calculated respectively

Step E: judging whether the parameter to be identified meets the following conditions, if not, adding 1 to the sampling frequency K, turning to the step C for circulation again, and if so, outputting the parameter to be identified as T and K_pCompleting online identification of the current value;

and step 3: based on the motion characteristics of the excavator rotary platform, the motion process of the excavator rotary platform is divided into stages to obtain the maximum control instruction input at each stage;

in a rotary control system, a control command is from an unmanned excavation main controller to a manipulator controller, a servo motor drives the manipulator to push a handle, when the rotary control system is started, the manipulator passes through a gap stroke with a certain distance, which is a reserved safety range of the excavator, and at the moment, a hydraulic system does not work, so that the hydraulic system needs to workAre to be identified separately. When the control command is changed from 0 step to a certain control command, the time delay is related to the size of the input control command, the larger the control command is, the shorter the time is, and the relation table tau between the determined delay time and the control command is determined by off-line calibration₁U, determining delay time according to a table look-up of a control command during online application; when the control command is stepped from one control command to 0, the time delay is basically unchanged and is recorded as tau₂。

If the rotary platform rapidly reaches the target angle, a maximum control instruction needs to be input to ensure that the rotary platform operates at the fastest speed, but the phenomenon that the actual rotary angle exceeds the target angle is easy to occur, so the invention divides the motion of the rotary platform into four stages, as shown in fig. 2.

Inputting a maximum control instruction u in the first stage_maxTo time t1 for a duration Δ t₁；

Second stage input control instruction 3u_max(ii)/4 until time t2 for duration Δ t₂；

Third stage input control instruction u_maxFrom/2 to time t3, duration Δ t₃；

And in the fourth stage, the control instruction is returned to zero, so that the excavator can freely rotate.

Wherein u is_maxAnd the control instruction is displayed when the manipulator pushes the excavator operating handle to the limit position.

Through multistage deceleration, the vibration caused by sudden cancellation of a control command can be reduced, and a smaller control command can be output when the target angle is too small, so that the situation that the rotation speed is too large and the rotation speed cannot be effectively decelerated due to too large input control command in the first stage is prevented.

And 4, step 4: the maximum control instruction duration of each stage is calibrated off line, and the maximum control instruction of each stage is combined and input into a motion control system model of the rotary platform of the excavator to obtain the rotary speed of the rotary platform of each stage, so that the motion control of the rotary platform of the unmanned excavator is realized.

The rotating speed of the rotating platform at each stage is obtained by calculation according to the following formula:

t_i＝t_i-1+Δt_i

wherein v is₀(t)＝0，t₀＝τ，t_iControl command stop input time, Δ t, representing the ith phase_iIndicating the duration of the control instruction, v, of the i-th phase_i(t) represents the revolving speed of the revolving platform at the ith stage, and u (i) represents the control command input at the ith stage.

By determining the control command durations, at, of the 2 nd and 3 rd phases off-line₂＝1s，Δt₃＝1s，t₀＝τ。

Under the current model, substituting the control instruction duration into a rotation speed formula can ensure that the speed can be reduced even at the maximum speed, the speed reduction lasts for a certain time, the stability is ensured, and the acceleration process duration can be calculated only if the deceleration process duration exists;

the accumulated target rotation angle of all stages can be obtained by integrating the rotation speed of each stage, the difference between the target rotation angle and the initial angle is obtained by utilizing, and the control instruction duration is solved by utilizing the fact that the free rotation at the last stage is finished, namely the rotation speed at the last rotation moment is 0;

wherein, t₁＝τ+Δt₁，t₂＝t₁+Δt₂，t₃＝t₂+Δt₃，t₄＝t₃+Δt₄；

Get v₄(t₄) When the value is approximately equal to 0, the free rotation is finished, and the free rotation time is obtained and is approximately delta t₄＝t₄-t₃＝T ln(|v₃(t₃)|)；

1) The delay time tau measured off-line, the duration of the control commands at of the second and third phases₂、Δt₃Found free wheeling time Δ t₄And the target rotation angle y is substituted into the rotation speed integral to solve the delta t₁A numerical solution of (c);

if Δ t₁Without numerical solution, the difference between the target rotation angle and the initial angle is too small, and the maximum rotation angle u does not need to be input in the first stage_maxI.e. Δ t₁＝0；

2) Will be Δ t ₁0, delay time τ measured off-line, and control command duration Δ t of the third stage₃Found free wheeling time Δ t₄And the target rotation angle y are substituted into the rotation speed integral to solve the control command 3u_maxDuration of/4 Δ t₂A numerical solution of (c);

if Δ t₂If no numerical solution exists, the difference between the target rotation angle and the initial angle is too small, and the maximum rotation angle 3u does not need to be input in the second stage_max/4, i.e. Δ t₂＝0；

3) Will be Δ t₁＝0，Δt₂Free-wheeling time Δ t obtained by off-line measurement of delay time τ as 0₄And the target rotation angle y is substituted into the rotation speed integral to solve the control command u_maxDuration of/2 Δ t₃A numerical solution of (c);

if Δ t₃If no numerical solution exists, the difference between the target gyration angle and the initial angle is too small, and the maximum gyration angle u does not need to be input in the third stage _max2, i.e. Δ t₃＝0。

Setting Δ t₁Firstly, acceleration is needed, but the acceleration time and the acceleration amount are unknown, and a target angle is needed to be input for solving;

calculated Δ t₁When there is no solution, because of the acceleration time Δ t₁When the value is 0, a control command u is input_maxWithout increasing the revolution speed in the stage (3 u)_maxThe/4 phase slew rate begins to increase but for a certain duration, the final slew angle will exceed the target angle.This is caused by the target angle being too small, and there is no need to input the control command u at this time_maxAnd (3) a stage of (a).

By obtaining the instruction duration of each stage, the excavator control is realized according to the following processes:

1. excavator input control instruction u_maxAnd t1, making the excavator tower rotate at the highest speed.

2. Excavator 3u_max/4 control instruction u_maxAnd t2, decelerating the excavator tower.

3. Excavator input u_maxControl instruction u/2_maxAnd t3, the excavator tower is decelerated again.

4. The excavator sets the control command to 0, enters a free rotation stage, the angle encoder detects an actual angle, and feedback control is realized by fine adjustment of the deviation of the actual angle and the calculated theoretical angle, as shown in fig. 4, the feedback control command u' is input at the moment and is calculated as follows:

u' (t) is a fine-tuned control command, err is a difference value between an angle measured by a sensor at the time t and a rotation speed integral calculation angle at each stage, and kp, Ti and Td are a proportional coefficient, an integral coefficient and a differential coefficient of the controller.

A motion control device of a revolving platform of an unmanned excavator comprises:

a system model construction unit: constructing a motion control system model of the excavator rotating platform based on a transfer function between the excavator rotating speed and a control instruction variable;

a system model parameter online identification unit: k in motion control system model of excavator rotating platform by recursive least square method_pAnd T, carrying out online identification;

a motion phase dividing unit: based on the motion characteristics of the excavator rotary platform, the motion process of the excavator rotary platform is divided into stages to obtain the maximum control instruction input at each stage;

revolution speed solving means: the maximum control instruction duration of each stage is calibrated and calculated off line, and the maximum control instruction of each stage is combined and input into a motion control system model of the rotary platform of the excavator to obtain the rotary speed of the rotary platform of each stage, so that the motion control of the rotary platform of the unmanned excavator is realized.

The embodiment of the invention also provides a readable storage medium, which comprises computer program instructions, and when the computer program instructions are executed by a processing terminal, the processing terminal executes the motion control method for the slewing platform of the unmanned excavator.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (8)

1. A motion control method of a rotary platform of an unmanned excavator is characterized by comprising the following steps:

step 1: constructing a motion control system model of the excavator rotating platform;

wherein, K_pT is a time constant and tau is a time delay for representing the gain coefficient of the rotation angular speed;

step 2: k in motion control system model of excavator rotating platform by recursive least square method_pAnd T, carrying out online identification;

and step 3: based on the motion characteristics of the excavator rotary platform, the motion process of the excavator rotary platform is divided into stages to obtain the maximum control instruction input at each stage;

wherein, the movement process of the excavator rotary platform is divided into 4 stages, and the maximum control instruction of each stage is u in sequence_max、3u_max/4、u_maxA/2, 0, wherein u_maxThe control instruction is used for showing a control instruction when the manipulator pushes the excavator operating handle to the limit position;

and 4, step 4: the maximum control instruction duration of each stage is calibrated off line, and the maximum control instruction of each stage is combined and input into a motion control system model of the rotary platform of the excavator to obtain the rotary speed of the rotary platform of each stage, so that the motion control of the rotary platform of the unmanned excavator is realized.

2. The method of claim 1, wherein the rotation speed of the rotating platform at each stage is calculated according to the following formula:

t∈(t_i-1,t_i-1+Δt_i)

t_i＝t_i-1+Δt_i

wherein v is₀(t)＝0，t₀＝τ，t_iControl command stop input time, Δ t, representing the ith phase_iIndicating the duration of the control instruction, v, of the i-th phase_i(t) represents the revolving speed of the revolving platform at the ith stage, and u (i) represents the control command input at the ith stage.

3. Method according to claim 2, characterized in that the control command duration, at, of the 2 nd and 3 rd phases is determined off-line₂＝1s，Δt₃＝1s，t₀＝τ。

4. The method according to claim 2, characterized in that the accumulated target turning angle of all stages is obtained by integrating the turning speed of each stage, the control instruction duration is solved by obtaining the difference between the target turning angle and the initial angle and by the end of the free turning at the last stage, i.e. the turning speed is 0 at the last turning moment;

wherein, t₁＝τ+Δt₁，t₂＝t₁+Δt₂，t₃＝t₂+Δt₃，t₄＝t₃+Δt₄；

Get v₄(t₄) When the value is approximately equal to 0, the free rotation is finished, and the free rotation time is obtained and is approximately delta t₄＝t₄-t₃＝Tln(|v₃(t₃)|)；

1) The delay time tau measured off-line, the duration of the control commands at of the second and third phases₂、Δt₃Found free wheeling time Δ t₄And the target rotation angle y is substituted into the rotation speed integral to solve the delta t₁A numerical solution of (c);

if Δ t₁Without numerical solution, the difference between the target rotation angle and the initial angle is too small, and the maximum rotation angle u does not need to be input in the first stage_maxI.e. Δ t₁＝0；

2) Will be Δ t₁0, delay time τ measured off-line, and control command duration Δ t of the third stage₃Found free wheeling time Δ t₄And the target rotation angle y are substituted into the rotation speed integral to solve the control command 3u_maxDuration of/4 Δ t₂A numerical solution of (c);

if Δ t₂If no numerical solution exists, the difference between the target rotation angle and the initial angle is too small, and the maximum rotation angle 3u does not need to be input in the second stage_max/4, i.e. Δ t₂＝0；

3) Will be Δ t₁＝0，Δt₂0, by off-lineMeasured delay time τ, free rotation time Δ t₄And the target rotation angle y is substituted into the rotation speed integral to solve the control command u_maxDuration of/2 Δ t₃A numerical solution of (c);

if Δ t₃If no numerical solution exists, the difference between the target gyration angle and the initial angle is too small, and the maximum gyration angle u does not need to be input in the third stage_max2, i.e. Δ t₃＝0。

5. The method of claim 1, wherein K is determined from a model of a motion control system for the revolving platform of the excavator by using a recursive least squares method_pAnd T, performing online identification by the following specific process:

step A: constructing a rotation speed state space equation and determining a recursion form;

revolution speed state space equation:

converting the above equation into a vector form:

the recursive form of the estimate of θ is set as:

wherein v (k) is a revolution angular velocity at the time k,

is the vector of the speed and the control command at the moment K-1, v (K-1) is the revolution angular speed measured by the sensor at the moment K-1, u (K-1) is the control command input at the moment K-1, and theta is the vector containing the parameters T and K to be identified_pThe expression of (1);

and

estimated parameters at time k and time k-1, respectively, K (k) is a gain matrix, v^*(k) Is the angular velocity of the revolution measured by the sensor,

a predicted value of a turning speed v (k) at the time k based on the history data at the time k-1;

and B: setting k to 1, initial value P (0) of covariance matrix to 10000 × E, E is unit matrix, initial estimation value of parameter

Is (1, 0), lambda is a forgetting factor, and the value is 0.95;

and C: recording sensor measurement data u (k) and v (k);

step D: k (k) is calculated, and then P (k) and P (k) are calculated respectively

Step E: judging whether the parameter to be identified meets the following conditions, if not, adding 1 to the sampling frequency K, turning to the step C for circulation again, and if so, outputting the parameter to be identified as T and K_pCompleting online identification of the current value;

6. a motion control device of a revolving platform of an unmanned excavator is characterized by comprising:

a system model construction unit: constructing a motion control system model of the excavator rotating platform based on a transfer function between the excavator rotating speed and a control instruction variable;

wherein, K_PT is a time constant and tau is a time delay for representing the gain coefficient of the rotation angular speed;

a system model parameter online identification unit: k in motion control system model of excavator rotating platform by recursive least square method_pAnd T, carrying out online identification;

a motion phase dividing unit: based on the motion characteristics of the excavator rotary platform, the motion process of the excavator rotary platform is divided into stages to obtain the maximum control instruction input at each stage; specifically, the movement process of the excavator rotary platform is divided into 4 stages, and the maximum control instruction of each stage is u in sequence_max、3u_max/4、u_maxA/2, 0, wherein u_maxThe control instruction is used for showing a control instruction when the manipulator pushes the excavator operating handle to the limit position;

revolution speed solving means: the maximum control instruction duration of each stage is calibrated and calculated off line, and the maximum control instruction of each stage is combined and input into a motion control system model of the rotary platform of the excavator to obtain the rotary speed of the rotary platform of each stage, so that the motion control of the rotary platform of the unmanned excavator is realized.

7. The apparatus of claim 6, wherein the revolving speed solving unit calculates the revolving speed of the revolving platform at each stage according to the following formula:

t∈(t_i-1,t_i-1+Δt_i)

t_i＝t_i-1+Δt_i

wherein v is₀(t)＝0，t₀＝τ₁，t_iControl command stop input time, Δ t, representing the ith phase_iIndicating the duration of the control instruction, v, of the i-th phase_i(t) a rotation speed of the rotation platform at the ith stage, and u (i) a control command for input at the ith stage;

a rotation speed solving unit for determining the control command duration, delta t, of the 2 nd and 3 rd stages off-line₂＝1s，Δt₃Obtaining the accumulated target rotation angle of all stages by integrating the rotation speed of each stage, obtaining the difference between the target rotation angle and the initial angle, and solving the control instruction duration by using the free rotation ending in the last stage, namely the rotation speed is 0 at the last rotation moment;

wherein, t₁＝τ+Δt₁，t₂＝t₁+Δt₂，t₃＝t₂+Δt₃，t₄＝t₃+Δt₄；

Get v₄(t₄) When the value is approximately equal to 0, the free rotation is finished, and the free rotation time is obtained and is approximately delta t₄＝t₄-t₃＝T ln(|v₃(t₃)|)；

1) The delay time tau measured off-line, the duration of the control commands at of the second and third phases₂、Δt₃Found free wheeling time Δ t₄And the target rotation angle y is substituted into the rotation speed integral to solve the delta t₁A numerical solution of (c);

if Δ t₁Without numerical solution, the difference between the target rotation angle and the initial angle is too small, and the maximum rotation angle u does not need to be input in the first stage_maxI.e. Δ t₁＝0；

2) Will be Δ t₁0, delay time τ measured off-line, and control command duration Δ t of the third stage₃Found free wheeling time Δ t₄And the target rotation angle y are substituted into the rotation speed integral to solve the control command 3u_maxDuration of/4 Δ t₂A numerical solution of (c);

if Δ t₂If no numerical solution exists, the difference between the target rotation angle and the initial angle is too small, and the maximum rotation angle 3u does not need to be input in the second stage_max/4, i.e. Δ t₂＝0；

3) Will be Δ t₁＝0，Δt₂Free-wheeling time Δ t obtained by off-line measurement of delay time τ as 0₄And the target rotation angle y is substituted into the rotation speed integral to solve the control command u_maxDuration of/2 Δ t₃A numerical solution of (c);

if Δ t₃If no numerical solution exists, the difference between the target gyration angle and the initial angle is too small, and the maximum gyration angle u does not need to be input in the third stage_max2, i.e. Δ t₃＝0。

8. A computer storage medium comprising a computer program, characterized in that the computer program, when executed by a processing terminal, causes the processing terminal to perform the method of any of claims 1-5.

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