CN102269995A - Variable structure control method of wheeled mobile robot - Google Patents

Abstract

The invention discloses a variable structure control method of a wheeled mobile robot. according the method, the linear motion of a robot is controlled by using a multimodal PID (proportion integration differentiation) control method; and a forward direction of a trolley is corrected by using the combination of a control method and a PID control and a rule control; the two control modes are switched through the changes of a directional angle and a centre offset; the robot is controlled to turn in an in-situ right angle turning mode according to turning direction information and position information; by using the multimode PID control and the combination of the rule control and the PID control, the algorithm can use different control algorithms and corresponding control parameters according to different states of the robot to effectively improve the robot motion control performance; the control mode is divided according to the error change condition so as to reasonably simulate the control behavior of a human; compared with the traditional PID control method, the variable structure control method has a certain intelligence and improves the walking motion control quality of the robot.

Description

The variable structure control method of wheeled mobile robot

Technical field

The present invention relates to a kind of control algolithm of wheeled mobile robot, specially refer to a kind of variable structure control method of wheeled mobile robot.

Background technology

All there is great Research Significance in robot aspect industries, universities and research institutors, wheeled robot research is a branch of robot research, the research category that belongs to the intelligent robot of can walking, it relates to computing machine, control automatically, sensing and numerous front subjects such as perception, wireless telecommunications, precision optical machinery and biomimetic material.Along with the continuous development of science and technology, the raising of material life, the mankind more want to break away from work heavy, dangerous, that repeat.So the use of robot more and more widely, and robot motion's research more and more comes into one's own.

Mobile robot's motion control problem is a problem the most basic in the robot research, also is the problem that only reliable control theory just can be solved in the robot research.For a control system that comprises controlling object, the theoretical research of control problem comprises two aspect contents, the one, control system analysis problem, the one, control system synthesis problem.In problem analysis,, determine the qualitative behavior (if can the property controlled, observability, stability etc.) and the quantitative Changing Pattern of control system according to known control input action.In synthtic price index, opposite with problem analysis just, according to desired controlled system forms of motion or some performance index, determine to put on the control input action of controlling object, i.e. control algolithm.

Improve robot motion's performance, the design of its bottom motion control arithmetic and be optimized to key.Design kinetic control system become to improve an important goal of wheel type machine robot system.

PID is the most frequently used control method, PID controller three parameters define computing method qualitatively.For proportional controller, its input quantity and output quantity are proportional, and the two does not postpone in time; Adopt integral action to solve steady-state error, but increase the phase lag of system, serious impair system response speed.Can adopt the method that in error enters certain limit, just begins integration to control effectively.When its function coefficient was too big, it is unstable that system is tending towards.But, can be again that system acting is slow if coefficient is too little.Under the prerequisite of system stability, add vast scale and regulate, can reduce steady-state error, but can not eliminate error; The control of employing differential, the control effect is rapid, generally is applicable to the system of free hysteresis, has the effect of leading adjusting, if improper but numerical value is selected, the input value of control system can be vibrated repeatedly, this causes system can't reach preset value forever.In addition, the PID controller lacks intelligent perception mechanism, and real-time is not strong, and running orbit is not accurate enough and stable, and can not take different control methods at different states.

In order to improve the adaptive ability of mobile robot's walking, there have document to propose to be a kind of with fuzzy algorithm and proportional integral combination of fuzzy proportional plus integral control algorithm, and be applied on the four-wheel mobile robot of independent development, but the regular domain of this method is difficult for dividing, and practical application is difficult for reaching simulated effect.

By being learned model, moveable robot movement analyzes, based on the two-wheel robot of vision, used parameter fuzzy to be applied in the moveable robot movement control from the PID control method of adjusting in the past, but this method, parameter is difficult for adjusting, and is difficult in the reality realizing.

Wheeled mobile robot is when the outer curve path trace, cause big tracking error in order to prevent oversteer and depart from predefined paths, there is document to propose a kind of energy and adapts to the course tracking and controlling method that turns to greatly, utilize the feedback information of the absolute direction of robot revolver drift angle as controller.But in actual applications, single deflection angle as feedback and not center offset as feedback information, can not reach excellent control effect.

There is document to propose design and carries out robot ambulation control based on the fuzzy controller that merges function.This method can reduce fuzzy rule, but The Design of Fuzzy Logic Controller is comparatively complicated, and the fuzzy controller in the practical application can not well be devised.

Suitable change structure control can make robot system reach the diverter surface of appointment in finite time, thereby realizes sliding formwork control.But, real system is because there is inertia inevitably in switching device shifter, variable structure control system switches in different steering logics back and forth, thereby to cause the control of actual sliding formwork be not to occur on the diverter surface exactly, cause the violent shake of system easily, thereby become its big obstacle in actual applications.

The mobile robot control algorithm is different from the control algolithm of General System.Common automatic control algorithm designs at specific application conditions often, only is used to finish certain specific function.And robot control algorithm need be finished multiple function, and all robot control systems nearly all are the fusions of various control algorithm.

Therefore be badly in need of a kind ofly when control robot is walked, can keeping its good characteristic, can improve the control algolithm of traditional control algolithm adaptivity again.

This patent proposes a kind of new variable structure control method that multi-modal control, rule control and PID control are merged, and is used for the walking movement control of wheeled mobile robot.

Summary of the invention

In view of this, in order to address the above problem, the present invention proposes a kind ofly can keep its good characteristic when control robot is walked, and can improve the control algolithm of traditional control algolithm adaptivity again; Multi-modal control, rule control are controlled the new variable structure control method that merges with PID, be used for the walking movement control of wheeled mobile robot.

The object of the present invention is achieved like this:

The variable structure control method of wheeled mobile robot provided by the invention, described wheeled mobile robot comprises revolver, right wheel, driver, front-seat Magnetic Sensor, back row's Magnetic Sensor, wheeled mobile robot car body, rfid interrogator, described driver control motor speed, comprise the straight line moving control and the control of turning, described straight line moving control comes the control robot straight line to move and proofread and correct the working direction of robot according to the differential information of robot revolver and right wheel drive motor; Described turning control provides the turn direction information of turning and the turning position information that magnetic stripe provides to determine robot turning information needed according to the RFID label, and employing original place right-angled bend mode is finished and controlled turning action.

Further, described straight line moving is controlled to be and becomes the structure control mode, comprises internal control ring and external control ring, and described internal control ring adopts the Multi-Mode PID control method to come the straight line of control robot to move; The working direction that the control method that described external control ring adopts PID control to combine with rule control is proofreaied and correct dolly; Described internal control ring and external control ring are changed according to following condition: when deflection θ=0 and center offset η＜d, by advancing of internal control ring control robot, otherwise adjusted the working direction of robot by the external control ring; Wherein d is two adjacent Magnetic Sensors intervals;

Further, described Multi-Mode PID control method may further comprise the steps:

S1: calculate the COEFFICIENT K in the Multi-Mode PID control _p, K _i, K _d,

K wherein _pThe expression scale-up factor, K _iThe expression integral coefficient, K _dThe expression differential coefficient;

S2: the robot movement information y (k) that input collects, y (k) is that current time revolver and right wheel speed are poor;

S3: calculation deviation e (k)=r (k)-y (k),

Wherein y (k) represents this sampling input quantity; R (k) represents given input quantity; The deviation of e (k) the given input quantity of expression and this sampling input quantity;

S4: by following formula calculation control amount:

u(k)＝u(k-1)+K _p(e(k)-e(k-1))+K _ie(k)+K _d(e(k)-2e(k-1)+e(k-2))

Wherein, the deviation of e (k) the given input quantity of expression and this sampling input quantity; Deviation between given input quantity of e (k-1) expression and the last time input quantity; E (k-2) expression specified rate and the deviation between the input quantity of sampling last time; U (k) expression needs the controlled quentity controlled variable of output; The controlled quentity controlled variable of the last output of u (k-1) expression;

S5: output controlled quentity controlled variable u (k), by the motion of robot driver module drive motor control robot;

S6: revise deviation by following formula, this deviation is set to deviation next time, and deviation is set to deviation last time next time:

e(k)→e(k-1)，e(k-1)→e(k-2)；

S7: judge whether the sampling time arrive, if no show, then writing down the sampling time finished up to the sampling time, entered next step;

S8:, then return the step S2 input of next time sampling if the sampling time finishes;

Further, the mode of also wanting elder generation to divide PID according to the situation of change of robot revolver and right wheel speed difference before the calculation control amount in the described step calculation control amount, described PID mode are divided and are carried out in such a way:

When revolver and right wheel speed difference during, use PID control less than default minimum threshold;

When revolver and right wheel speed difference during, use P control greater than default max-thresholds;

When revolver and right wheel speed difference are between default minimum threshold and default max-thresholds, use PI control;

Described default minimum threshold is got 1r/min, and described default max-thresholds is got 2r/min;

Further, described external control ring may further comprise the steps:

S21: utilize the Magnetic Sensor of robot front and back end and magnetic stripe position to gather the position error signal of robot and calculate the attitude of robot;

S22: judge whether robot pose deviation occurs, if deviation do not occur, then robot keeps original attitude to move;

S23: if deviation adopts following formula to calculate controlled quentity controlled variable:

e(k)＝k ₁η(k)+k ₂θ(k)

u(k)＝u(k-1)+K _p(e(k)-e(k-1))+K _ie(k)+K _d(e(k)-2e(k-1)+e(k-2))

Wherein, k ₁The scale-up factor of expression center offset, k ₂Represent azimuthal scale-up factor, k ₁, k ₂Value to determine according to the attitude of robot; The deviation of e (k) the given input quantity of expression and this sampling input quantity; Deviation between given input quantity of e (k-1) expression and the last time input quantity; E (k-2) expression specified rate and the deviation between the input quantity of sampling last time; U (k) expression needs the controlled quentity controlled variable of output; The last output quantity of u (k-1) expression; η (k) represents that this detects the distance at center, robot center line distance path; θ (k) represents that this detects the deflection of robot;

S24: the deviation angle according to the robot of sensor is determined turning to of robot;

S25: determine dolly turn to after again according to controlled quentity controlled variable, send voltage for the driver corresponding port, thereby adjust turning to of robot two driving wheel rotating speed of motor and wheel;

Further, further comprising the steps of:

S9: when robot has run out of the scope of magnetic stripe at operational process, then carry out the forward video navigation, the information of side-play amount and off-centring distance is provided for kinetic control system by the forward video navigational system;

Further, described turning control may further comprise the steps:

S11: when the robot straight line moving, obtain the turn direction information of RFID label, detect the turning position information that magnetic stripe provides by Magnetic Sensor by rfid interrogator;

S12: stop motion after the time expand that the robot motion presets;

S13: the zone bit that provides according to the FRID label is judged the directional information of the turning of determining robot;

S14: according to the directional information of turning, allow a corresponding wheel turns, another wheel stops;

S15: detect magnetic stripe, judge whether magnetic stripe is positioned in the middle of front-seat magnetic sensing and the back row's magnetic sensing; If magnetic stripe is not positioned in the middle of front-seat magnetic sensing and the back row's magnetic sensing, then returns step S14 and continue to turn;

S16:, then stop to turn if magnetic stripe is positioned in the middle of front-seat magnetic sensing and the back row's magnetic sensing;

Further, calculation deviation comprises calculating angle and the two-part departure of offset distance in the described S3 step;

Further, described center offset calculates by following formula:

$\mathrm{\&eta;}=\frac{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000070300860000021.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000070300860000041.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}{2}$

Calculate by following formula at described position angle:

$\tan \mathrm{\&theta;}=\frac{L_1-L_2}{L}$

Wherein, L ₁The distance of the front-seat Magnetic Sensor sense of magnetic stripe apart from center line, L are sensed in expression ₂The distance of the front-seat Magnetic Sensor sense of magnetic stripe apart from center line sensed in expression, the distance of two row's Magnetic Sensors before and after L represents.

The invention has the advantages that: adopt Multi-Mode PID control, the input quantity of this control method is the rotary speed information of two wheels, constitutes the internal control ring, and the straight line of control robot moves; Also adopt rule control to combine with PID control, the input quantity of this control method is the position of robot (deflection and center offset) information, constitutes the working direction that the external control ring is used for proofreading and correct robot; When satisfying the condition that inside and outside control loop switch,, otherwise adjust the working direction of robot by the external control ring by advancing of internal control ring control robot; The control mode that the PID control of determining according to the motor driver special principle combines with rule control, this algorithm adopts different control algolithm and control corresponding parameter at the residing different conditions of robot, improves and improved the machine movement control performance effectively.

Multi-Mode PID control method provided by the invention, divide control mode according to the error change situation, people's control experience and skill have been imitated to a certain extent, more reasonably simulated people's control behavior, more traditional PID control method, have certain intelligently, improved robot ambulation motion control quality.

Other advantage of the present invention, target and feature will be set forth to a certain extent in the following description, and to a certain extent, based on being conspicuous to those skilled in the art, perhaps can obtain instruction from the practice of the present invention to investigating hereinafter.The objectives and other advantages of the present invention can be passed through following instructions, claims, and the specifically noted structure realizes and obtains in the accompanying drawing.

Description of drawings

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with accompanying drawing, wherein:

Fig. 1 is the automatic motion control control principle of straight line figure;

Fig. 2 is a PID control flow block diagram;

Fig. 3 is the synoptic diagram of the rule 1 of trolley travelling course attitude;

Fig. 4 is the synoptic diagram of the rule 2 of trolley travelling course attitude;

Fig. 5 is the synoptic diagram of the rule 3 of trolley travelling course attitude;

Fig. 6 is the synoptic diagram of the rule 4 of trolley travelling course attitude;

Fig. 7 is the synoptic diagram of the rule 5 of trolley travelling course attitude;

Fig. 8 is the synoptic diagram of the rule 6 of trolley travelling course attitude;

Fig. 9 is the navigational system structural drawing;

Figure 10 is turning magnetic stripe and RFID label position layout synoptic diagram;

Figure 11 is a dolly turning control flow.

The 1 expression magnetic stripe line of induction, the front-seat Magnetic Sensor of 2 expressions, 3 expression back row's Magnetic Sensors, 4 expression center offset η, the 5 expression working direction angle θ of robot, 6 expression rfid interrogators, 7 expression magnetic stripes, 8 expression prompting turning information magnetic stripes, 9 expression RFID labels, 10 expression magnetic stripe mounting grooves.

Embodiment

Below with reference to accompanying drawing, the preferred embodiments of the present invention are described in detail; Should be appreciated that preferred embodiment only for the present invention is described, rather than in order to limit protection scope of the present invention.

The variable structure control method of wheeled mobile robot provided by the invention, described wheeled mobile robot comprises revolver, right wheel, driver, front-seat Magnetic Sensor, back row's Magnetic Sensor, wheeled mobile robot car body, rfid interrogator, described driver control motor speed, comprise the straight line moving control and the control of turning, described straight line moving control comes the control robot straight line to move and proofread and correct the working direction of robot according to the differential information of robot revolver and right wheel drive motor; Described turning control provides the turn direction information of turning and the turning position information that magnetic stripe provides to determine robot turning information needed according to the RFID label, and employing original place right-angled bend mode is finished and controlled turning action.

Fig. 1 is the automatic motion control control principle of straight line figure; As shown in the figure, as the further improvement of the foregoing description, described straight line moving is controlled to be and becomes the structure control mode, comprises internal control ring and external control ring, and described internal control ring adopts the Multi-Mode PID control method to come the straight line of control robot to move; The working direction that the control method that described external control ring adopts PID control to combine with rule control is proofreaied and correct dolly; Described internal control ring and external control ring are changed according to following condition: when deflection θ=0 and center offset η＜d, by advancing of internal control ring control robot, otherwise adjusted the working direction of robot by the external control ring; Wherein d is two adjacent Magnetic Sensors intervals, K ₁The scale-up factor of expression center offset, K ₂Represent azimuthal scale-up factor.

Fig. 2 is a PID control flow block diagram; As shown in the figure, as the further improvement of the foregoing description, described Multi-Mode PID control method may further comprise the steps:

S1: calculate the COEFFICIENT K in the Multi-Mode PID control _p, K _i, K _d,

K wherein _pThe expression scale-up factor, K _iThe expression integral coefficient, K _dThe expression differential coefficient;

S2: the robot movement information y (k) that input collects, y (k) is that current time revolver and right wheel speed are poor;

S3: calculation deviation e (k)=r (k)-y (k),

Wherein y (k) represents this sampling input quantity; R (k) represents given input quantity; The deviation of e (k) the given input quantity of expression and this sampling input quantity;

S4: by following formula calculation control amount:

u(k)＝u(k-1)+K _p(e(k)-e(k-1))+K _ie(k)+K _d(e(k)-2e(k-1)+e(k-2))

Wherein, the deviation of e (k) the given input quantity of expression and this sampling input quantity; Deviation between given input quantity of e (k-1) expression and the last time input quantity; E (k-2) expression specified rate and the deviation between the input quantity of sampling last time; U (k) expression needs the controlled quentity controlled variable of output; The controlled quentity controlled variable of the last output of u (k-1) expression;

S5: output controlled quentity controlled variable u (k), by the motion of robot driver module drive motor control robot;

S6: revise deviation by following formula, this deviation is set to deviation next time, and deviation is set to deviation last time next time:

e(k)→e(k-1)，e(k-1)→e(k-2)；

S7: judge whether the sampling time arrive, if no show, then writing down the sampling time finished up to the sampling time, entered next step;

S8:, then return the step S2 input of next time sampling if the sampling time finishes.

As the further improvement of the foregoing description, the mode of also wanting elder generation to divide PID according to the situation of change of robot revolver and right wheel speed difference before the calculation control amount in the described step calculation control amount, described PID mode are divided and are carried out in such a way:

When revolver and right wheel speed difference during less than default minimum threshold, use PID control, promptly adopt ratio, integration, three kinds of control laws of differential to control;

When revolver and right wheel speed difference during greater than default max-thresholds, use P control, promptly adopt the proportional control rule to control;

When revolver and right wheel speed difference are between default minimum threshold and default max-thresholds, use PI control, promptly adopt the control law of ratio, integration to control;

Described default minimum threshold is got 1r/min, and described default max-thresholds is got 2r/min.

Fig. 9 is the navigational system structural drawing, the wherein distributing position of rfid interrogator 6 on dolly, and magnetic stripe 7 setting on the way, and the control detailed process of turning is: read RFID label 9 when straight line moving, navigational system has obtained the directional information of turning.When Magnetic Sensor detects the magnetic stripe 8 of the prompting turning information more than 4 or 4, be defined as and detect turning mark, dolly stops immediately, from navigational system, take out the directional information of turning, allow a corresponding wheel turns, another wheel stops, and detects Magnetic Sensor simultaneously, when the front and rear row Magnetic Sensor sense the magnetic stripe that is installed in the magnetic stripe mounting groove 10 be positioned in the middle of the time, dolly moves on.After turning is finished, empty the directional information of the turning of navigational system.After the directional information of the turning that empties navigational system, if when Magnetic Sensor is read the magnetic stripe 8 of the prompting turning information more than 4 or 4, robot does not turn yet, to avoid the robot maloperation.As shown in the figure: as the further improvement of the foregoing description, described external control ring may further comprise the steps:

S21: utilize the Magnetic Sensor of robot front and back end and magnetic stripe position to gather the position error signal of robot and calculate the attitude of robot;

S22: judge whether robot pose deviation occurs, if deviation do not occur, then robot keeps original attitude to move;

S23: if deviation adopts following formula to calculate controlled quentity controlled variable:

e(k)＝k ₁η(k)+k ₂θ(k)

u(k)＝u(k-1)+K _p(e(k)-e(k-1))+K _ie(k)+K _d(e(k)-2e(k-1)+e(k-2))

Wherein, k ₁The scale-up factor of expression center offset, k ₂Represent azimuthal scale-up factor, k ₁, k ₂Value to determine according to the attitude of robot; The deviation of e (k) the given input quantity of expression and this sampling input quantity; Deviation between given input quantity of e (k-1) expression and the last time input quantity; E (k-2) expression specified rate and the deviation between the input quantity of sampling last time; U (k) expression needs the controlled quentity controlled variable of output; The last output quantity of u (k-1) expression; η (k) represents that this detects the distance at center, robot center line distance path; θ (k) represents that this detects the deflection of robot;

Wherein, k ₁, k ₂Value to determine according to the on-the-spot repetition test of the attitude of dolly.

S24: the deviation angle according to the robot of sensor is determined turning to of robot;

S25: determine dolly turn to after again according to controlled quentity controlled variable, send voltage for the driver corresponding port, thereby adjust turning to of robot two driving wheel rotating speed of motor and wheel.

As the further improvement of the foregoing description, calculation deviation comprises calculating angle and the two-part departure of offset distance in the described S3 step, and described center offset calculates by following formula:

$\mathrm{\&eta;}=\frac{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000070300860000021.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000070300860000041.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}{2}$

Calculate by following formula at described position angle:

$\tan \mathrm{\&theta;}=\frac{L_1-L_2}{L}$

Wherein, L ₁The distance of the front-seat Magnetic Sensor sense of magnetic stripe apart from center line, L are sensed in expression ₂The distance of the front-seat Magnetic Sensor sense of magnetic stripe apart from center line sensed in expression, the distance of two row's Magnetic Sensors before and after L represents.

L ₁, L ₂Be the number that symbol is arranged, the regulation left avertence is for negative, and right avertence is for just.

Fig. 3 to Fig. 8 is the synoptic diagram of trolley travelling course attitude; The magnetic stripe line of induction 1, front-seat Magnetic Sensor 2, back row's Magnetic Sensor 3, center offset η 4, the working direction angle θ of robot 5 among the figure, the attitude of robot is passed through following rule description:

Fig. 3 is the synoptic diagram of the rule 1 of trolley travelling course attitude; As shown in the figure, regular 1:L ₁＜0, L ₂＞0, dolly should be proofreaied and correct left.When θ=0, during η＜d, carry out straight line moving and proofread and correct control.D is the interval of adjacent two Magnetic Sensors.

Fig. 4 is the synoptic diagram of the rule 2 of trolley travelling course attitude; As shown in the figure, regular 2:L ₁＞0, L ₂＜0, dolly should be proofreaied and correct to the right.When θ=0, during η＜d, carry out straight line moving and proofread and correct control.

Fig. 5 is the synoptic diagram of the rule 3 of trolley travelling course attitude; As shown in the figure, regular 3:L ₁＜0, L ₂＜0, θ＞0, dolly should be to keeping direction of motion constant.When becoming attitude rule 2, carry out the correction program of attitude rule 2.

Fig. 6 is the synoptic diagram of the rule 4 of trolley travelling course attitude; As shown in the figure, regular 4:L ₁＜0, L ₂＜0, θ＜0, dolly should be proofreaied and correct left.When θ=0, during η＜d, carry out straight line moving and proofread and correct control.

Fig. 7 is the synoptic diagram of the rule 5 of trolley travelling course attitude; As shown in the figure, regular 5:L ₁＞0, L ₂＞0, θ＜0, dolly should be to keeping direction of motion constant.When becoming attitude rule 1, the correction program of executing rule 1.

Fig. 8 is the synoptic diagram of the rule 6 of trolley travelling course attitude; As shown in the figure, regular 6:L ₁＞0, L ₂＞0, θ＞0, dolly should be proofreaied and correct to the right.When θ=0, during η＜d, carry out straight line moving and proofread and correct control.

As the further improvement of the foregoing description, further comprising the steps of:

S9: when robot has run out of the scope of magnetic stripe at operational process, then carry out the forward video navigation, the information of side-play amount and off-centring distance is provided for kinetic control system by the forward video navigational system.

Figure 10 is turning magnetic stripe and RFID label position layout synoptic diagram; Figure 11 is a dolly turning control flow, 4 magnetic stripes of 8 expression prompting turning information, 9 expression RFID labels, 10 expression magnetic stripe mounting grooves.

As shown in the figure, as the further improvement of the foregoing description, described turning control may further comprise the steps:

S11: when the robot straight line moving, obtain the turn direction information of RFID label, detect the turning position information that magnetic stripe provides by Magnetic Sensor by rfid interrogator;

S12: stop motion after the time expand that the robot motion presets;

S13: the zone bit that provides according to the FRID label is judged the directional information of the turning of determining robot;

S14: according to the directional information of turning, allow a corresponding wheel turns, another wheel stops;

S15: detect magnetic stripe, judge whether magnetic stripe is positioned in the middle of front-seat magnetic sensing and the back row's magnetic sensing; If magnetic stripe is not positioned in the middle of front-seat magnetic sensing and the back row's magnetic sensing, then returns step S14 and continue to turn;

S16:, then stop to turn if magnetic stripe is positioned in the middle of front-seat magnetic sensing and the back row's magnetic sensing.

The above is the preferred embodiments of the present invention only, is not limited to the present invention, and obviously, those skilled in the art can carry out various changes and modification and not break away from the spirit and scope of the present invention the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (9)

1. the variable structure control method of wheeled mobile robot, described wheeled mobile robot comprises revolver, right wheel, driver, front-seat Magnetic Sensor, back row's Magnetic Sensor, wheeled mobile robot car body, rfid interrogator, described driver control motor speed, it is characterized in that: comprise the straight line moving control and the control of turning, described straight line moving control comes the control robot straight line to move and proofread and correct the working direction of robot according to the differential information of robot revolver and right wheel drive motor; Described turning control provides the turn direction information of turning and the turning position information that magnetic stripe provides to determine robot turning information needed according to the RFID label, and employing original place right-angled bend mode is finished and controlled turning action.

2. the variable structure control method of wheeled mobile robot according to claim 1, it is characterized in that: described straight line moving is controlled to be the structure control mode that becomes, comprise internal control ring and external control ring, described internal control ring adopts the Multi-Mode PID control method to come the straight line of control robot to move; The working direction that the control method that described external control ring adopts PID control to combine with rule control is proofreaied and correct dolly; Described internal control ring and external control ring are changed according to following condition: when deflection θ=0 and center offset η＜d, by advancing of internal control ring control robot, otherwise adjusted the working direction of robot by the external control ring; Wherein d is two adjacent Magnetic Sensors intervals.

3. the variable structure control method of wheeled mobile robot according to claim 2, it is characterized in that: described Multi-Mode PID control method may further comprise the steps:

S1: calculate the COEFFICIENT K in the Multi-Mode PID control _p, K _i, K _d,

K wherein _pThe expression scale-up factor, K _iThe expression integral coefficient, K _dThe expression differential coefficient;

S2: the robot movement information y (k) that input collects, y (k) is that current time revolver and right wheel speed are poor;

S3: calculation deviation e (k)=r (k)-y (k),

Wherein y (k) represents this sampling input quantity; R (k) represents given input quantity; The deviation of e (k) the given input quantity of expression and this sampling input quantity;

S4: by following formula calculation control amount:

u(k)＝u(k-1)+K _p(e(k)-e(k-1))+K _ie(k)+K _d(e(k)-2e(k-1)+e(k-2))

Wherein, the deviation of e (k) the given input quantity of expression and this sampling input quantity; Deviation between given input quantity of e (k-1) expression and the last time input quantity; E (k-2) expression specified rate and the deviation between the input quantity of sampling last time; U (k) expression needs the controlled quentity controlled variable of output; The controlled quentity controlled variable of the last output of u (k-1) expression;

S5: output controlled quentity controlled variable u (k), by the motion of robot driver module drive motor control robot;

S6: revise deviation by following formula, this deviation is set to deviation next time, and deviation is set to deviation last time next time:

e(k)→e(k-1)，e(k-1)→e(k-2)；

S7: judge whether the sampling time arrive, if no show, then writing down the sampling time finished up to the sampling time, entered next step;

S8:, then return the step S2 input of next time sampling if the sampling time finishes.

4. the variable structure control method of wheeled mobile robot according to claim 3, it is characterized in that: the mode of also wanting elder generation to divide PID according to the situation of change of robot revolver and right wheel speed difference before the calculation control amount in the described step calculation control amount, described PID mode are divided and are carried out in such a way:

When revolver and right wheel speed difference during, use PID control less than default minimum threshold;

When revolver and right wheel speed difference during, use P control greater than default max-thresholds;

When revolver and right wheel speed difference are between default minimum threshold and default max-thresholds, use PI control;

Described default minimum threshold is got 1r/min, and described default max-thresholds is got 2r/min.

5. the variable structure control method of wheeled mobile robot according to claim 2, it is characterized in that: described external control ring may further comprise the steps:

S21: utilize the Magnetic Sensor of robot front and back end and magnetic stripe position to gather the position error signal of robot and calculate the attitude of robot;

S22: judge whether robot pose deviation occurs, if deviation do not occur, then robot keeps original attitude to move;

S23: if deviation adopts following formula to calculate controlled quentity controlled variable:

e(k)＝k ₁η(k)+k ₂θ(k)

u(k)＝u(k-1)+K _p(e(k)-e(k-1))+K _ie(k)+K _d(e(k)-2e(k-1)+e(k-2))

Wherein, k ₁The scale-up factor of expression center offset, k ₂Represent azimuthal scale-up factor, k ₁, k ₂Value to determine according to the attitude of robot; The deviation of e (k) the given input quantity of expression and this sampling input quantity; Deviation between given input quantity of e (k-1) expression and the last time input quantity; E (k-2) expression specified rate and the deviation between the input quantity of sampling last time; U (k) expression needs the controlled quentity controlled variable of output; The last output quantity of u (k-1) expression; η (k) represents that this detects the distance at center, robot center line distance path; θ (k) represents that this detects the deflection of robot;

S24: the deviation angle according to the robot of sensor is determined turning to of robot;

S25: determine dolly turn to after again according to controlled quentity controlled variable, send voltage for the driver corresponding port, thereby adjust turning to of robot two driving wheel rotating speed of motor and wheel.

6. the variable structure control method of wheeled mobile robot according to claim 5 is characterized in that: further comprising the steps of:

S9: when robot has run out of the scope of magnetic stripe at operational process, then carry out the forward video navigation, the information of side-play amount and off-centring distance is provided for kinetic control system by the forward video navigational system.

7. the variable structure control method of wheeled mobile robot according to claim 1 is characterized in that: described turning control may further comprise the steps:

S11: when the robot straight line moving, obtain the turn direction information of RFID label, detect the turning position information that magnetic stripe provides by Magnetic Sensor by rfid interrogator;

S12: stop motion after the time expand that the robot motion presets;

S13: the zone bit that provides according to the FRID label is judged the directional information of the turning of determining robot;

S14: according to the directional information of turning, allow a corresponding wheel turns, another wheel stops;

S15: detect magnetic stripe, judge whether magnetic stripe is positioned in the middle of front-seat magnetic sensing and the back row's magnetic sensing; If magnetic stripe is not positioned in the middle of front-seat magnetic sensing and the back row's magnetic sensing, then returns step S14 and continue to turn;

S16:, then stop to turn if magnetic stripe is positioned in the middle of front-seat magnetic sensing and the back row's magnetic sensing.

8. the variable structure control method of wheeled mobile robot according to claim 3 is characterized in that: calculation deviation comprises and calculates angle and the two-part departure of offset distance in the described S3 step.

9. the variable structure control method of wheeled mobile robot according to claim 8 is characterized in that: described center offset calculates by following formula:

$\mathrm{\&eta;}=\frac{L_1+L_2}{2}$

Calculate by following formula at described position angle:

$\tan \mathrm{\&theta;}=\frac{L_1-L_2}{L}$

Wherein, L ₁The distance of the front-seat Magnetic Sensor sense of magnetic stripe apart from center line, L are sensed in expression ₂The distance of the front-seat Magnetic Sensor sense of magnetic stripe apart from center line sensed in expression, the distance of two row's Magnetic Sensors before and after L represents.

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