CN111293949B - Control method of anti-interference electric six-degree-of-freedom parallel mechanism - Google Patents
Control method of anti-interference electric six-degree-of-freedom parallel mechanism Download PDFInfo
- Publication number
- CN111293949B CN111293949B CN202010207104.5A CN202010207104A CN111293949B CN 111293949 B CN111293949 B CN 111293949B CN 202010207104 A CN202010207104 A CN 202010207104A CN 111293949 B CN111293949 B CN 111293949B
- Authority
- CN
- China
- Prior art keywords
- motor
- torque
- control
- actuator
- follows
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 38
- 230000007246 mechanism Effects 0.000 title claims abstract description 24
- 230000001133 acceleration Effects 0.000 claims abstract description 13
- 238000013178 mathematical model Methods 0.000 claims abstract description 5
- 230000005540 biological transmission Effects 0.000 claims description 18
- 238000013016 damping Methods 0.000 claims description 13
- 238000012546 transfer Methods 0.000 claims description 12
- 238000006073 displacement reaction Methods 0.000 claims description 10
- 238000013461 design Methods 0.000 claims description 9
- 239000011159 matrix material Substances 0.000 claims description 9
- 230000009347 mechanical transmission Effects 0.000 claims description 9
- 230000001360 synchronised effect Effects 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 6
- 238000004364 calculation method Methods 0.000 claims description 4
- 238000012937 correction Methods 0.000 claims description 3
- 238000003745 diagnosis Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 230000008878 coupling Effects 0.000 abstract description 4
- 238000010168 coupling process Methods 0.000 abstract description 4
- 238000005859 coupling reaction Methods 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 3
- 230000008859 change Effects 0.000 description 7
- 238000011217 control strategy Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004422 calculation algorithm Methods 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 238000006880 cross-coupling reaction Methods 0.000 description 1
- 230000036544 posture Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/0004—Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/0004—Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control
- H02P23/0027—Control strategies in general, e.g. linear type, e.g. P, PI, PID, using robust control using different modes of control depending on a parameter, e.g. the speed
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/12—Observer control, e.g. using Luenberger observers or Kalman filters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/14—Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/08—Arrangements for controlling the speed or torque of a single motor
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/34—Modelling or simulation for control purposes
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P2207/00—Indexing scheme relating to controlling arrangements characterised by the type of motor
- H02P2207/05—Synchronous machines, e.g. with permanent magnets or DC excitation
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Feedback Control In General (AREA)
Abstract
The invention discloses an anti-interference control method for an electric six-freedom-degree parallel mechanism, which comprises the steps of firstly establishing a mathematical model of the mechanism aiming at the characteristics of nonlinearity, strong coupling and the like of the electric six-freedom-degree parallel mechanism, designing a cascade control model based on a hinge space of a linear actuator and an attitude space of a motion platform, taking control based on a hinge point space as an inner ring and taking control based on the attitude space of the motion platform as an outer ring, and adopting PID controllers for the two. Aiming at the characteristics that the load torque of a single linear actuator of a six-degree-of-freedom parallel mechanism changes in real time and influences the control precision, the angular acceleration information of the actuator is acquired by adopting a state observer, and an anti-interference compensation controller is designed on the basis of the angular acceleration information so as to eliminate the influence of disturbance on the control precision. And finally, obtaining the optimal PID control parameter by using a Zieler-Nichols PID parameter setting method. The control effect of the method on the electric six-degree-of-freedom parallel mechanism is superior to that of the traditional PID method based on the hinge space.
Description
Technical Field
The invention belongs to the field of automatic control of systems, and particularly relates to a control method of an anti-interference electric six-degree-of-freedom parallel mechanism.
Background
In recent years, a control algorithm of a six-degree-of-freedom parallel mechanism becomes one of research hotspots of scholars at home and abroad, and the six-degree-of-freedom parallel mechanism is taken as a large branch of an industrial robot, has the advantages of large bearing capacity, strong rigidity, high precision, simple design and the like, is widely applied to military and civil fields such as ships, aviation, electric power, vehicles and the like, and has extremely wide application prospect. The six-degree-of-freedom parallel mechanism is a complex system with the characteristics of nonlinearity, strong coupling and static instability, and has certain difficulty in realizing efficient and stable control. Meanwhile, due to the change of the load and the motion characteristic of the load, the load of each linear actuating mechanism is changed in real time, and the change characteristic is difficult to obtain, so that the control difficulty is further increased. Therefore, the control method for designing the high-performance six-degree-of-freedom parallel mechanism has very important application value.
The PID controller which controls according to the proportion (P), the integral (I) and the differential (D) of the deviation is the most widely applied six-freedom-degree parallel mechanism controller and has the characteristics of simplicity, stability and easy realization. However, as the complexity of the system is higher and higher, and the system parameters and the working environment are changed continuously, the conventional PID controller is difficult to meet the precise control requirement. New controllers need to be designed to meet the complex control requirements.
In the existing research results, the attitude control of the parallel mechanism is mostly designed based on an actuator hinge space model, the coupling effect between an attitude space and each actuator is not considered, and the control effect is difficult to guarantee when model uncertainty and external interference exist. The six-degree-of-freedom electric motion platform has the characteristic of serious nonlinearity, is a space multi-degree-of-freedom and multi-parameter cross coupling system, and the research on the control method mainly comprises a control strategy based on a hinge point space and a control strategy based on a mechanism dynamic model. The former is a traditional control mode, and six linear actuators of the motion platform are regarded as independent single-channel systems to be controlled. For each electric servo system, the load characteristic is changed at any time along with the pose change of the moving platform, in the process of designing the control system, the load characteristic is equivalent to equivalent interference force and equivalent mass, however, the moving platform of the six-degree-of-freedom parallel mechanism is in different poses, the equivalent mass change is large, and meanwhile, the equivalent interference force change is very large. On the basis of comprehensively considering the dynamic characteristics of the system and the dynamic performance of each channel, the controller is designed by adopting a control strategy based on a system dynamic model, the overall performance of the system can be improved, but when the load has a time-varying characteristic, the control effect is not obvious, the modeling is difficult, and the calculation amount is large.
Disclosure of Invention
In order to solve the problems, the invention discloses an anti-interference electric six-degree-of-freedom parallel mechanism control method, which aims at the six-degree-of-freedom parallel mechanism with strong interference, uncertain model and coupling of each channel and realizes accurate attitude control.
In order to achieve the purpose, the technical scheme of the invention is as follows:
an anti-interference electric six-degree-of-freedom parallel mechanism control method comprises the following steps:
step 1), the actuator researched by the invention is a linear guide rail type actuator driven by a permanent magnet synchronous servo motor, the transmission part of the actuator is a ball screw, the screw transmission part in the system is simplified into an ideal model, and the screw transmission part is equivalent to a mathematical model mainly considering the rigidity, the damping and the rotational inertia of the screw transmission part:
step 1.1), obtaining a torque balance equation according to the transmission characteristics of the screw rod, wherein the torque balance equation is as follows:
wherein, J L Calculating the total moment of inertia of the motor for the mechanical transmission part, B L Calculating the total viscous damping coefficient, T, to the motor for the mechanical transmission part L (T) is the load torque, T m (t) motor output torque, θ L And (t) is the output rotation angle of the screw rod.
Step 1.2), according to a screw stiffness formula, a screw driving torque can be expressed as:
T m =K L [θ e -θ L ]
wherein, T L (t) is the output torque of the motor, K L For converting the mechanical transmission part into the total rotational stiffness, theta, of the output shaft of the linear actuator e (t) is the motor output rotation angle, θ L And (t) is the output rotation angle of the screw rod.
Step 1.3), the relationship between the expansion amount of the linear actuator and the output displacement of the screw shaft is as follows:
wherein, theta L (t) is the motor output rotation angle, P h For transmission lead, X L Is the linear displacement of the screw rod.
And step 2), modeling the permanent magnet synchronous servo motor.
Step 2.1), a driving motor torque model is established, the model adopts a permanent magnet synchronous servo motor, and the torque equation process expression is as follows:
T e (t)=K t i q (t)
wherein, T e (T) is the electromagnetic torque of the machine, T L (t) load torque, J moment of inertia, K t Is a torque constant, i q And (t) is a q-axis stator current. B is the damping coefficient of the motor, theta e And (t) is the output rotation angle of the motor.
And 2.2) establishing a driving motor control model. The servo motor of the system is a speed ring structure, the speed controller is a PI controller, and the current ring is used as an inner ring of the speed ring controller.
The closed loop transfer function of the current loop is equivalent to a first-order inertia link, omega c Current loop bandwidth:
the transfer function of the motor current to the electromagnetic torque is:
MI(s)=K t i q (t)
wherein, K t Is the motor torque constant, i q (t) is a q-axis current.
The electromagnetic torque to motor speed transfer function is:
wherein, J moment of inertia, B damping coefficient.
The digital low pass filter is designed to suppress high frequency noise in the velocity signal with a transfer function of, where f For the filter bandwidth:
and step 3), designing a cascade controller. And taking control based on a hinge point space as an inner ring and taking control based on a motion platform attitude space as an outer ring. The inner ring controller is a single-input single-output system loop formed by each supporting leg, a PID controller is adopted, and a feedback signal is measured by a linear displacement sensor. The outer ring is compensation control based on an attitude space, the actual measurement attitude is obtained through positive solution to realize the correction of the input attitude, and a PID control method is adopted. The system is positively solved, namely the space attitude of the moving platform is calculated through the length of the supporting leg, a Newton-Raphson iteration method is adopted, and the method comprises the following specific steps:
step 3.1), the distance formula between the hinge points of the linear actuator is as follows:
Δl i =l i -l 0
wherein l i Is the ith actuator length, g ki For the coordinates of the points after the moving coordinate system has been transformed into the stationary coordinate system, b ki As coordinate points of the reference system, l 0 To the initial length of the actuator, Δ l i Corresponding to the expansion amount of the actuator.
Step 3.2), solving the moving platform attitude by utilizing linearization processing and a Newton-Raphson iteration method, wherein the equation is as follows:
obtaining a nonlinear equation system containing six unknowns:
wherein,q=[q 1 ,q 2 …q 6 ] T =[x,y,z,α,β,γ] T representing six poses of the motion platform, respectively.
And 3.3) solving a nonlinear equation system. In the general formula f i (q 1 ,q 2 …q 6 ) At point (q) 10 ,q 20 …q 60 ) Performing binary Taylor series expansion nearby, and taking the linear part of the binary Taylor series expansion to obtain:
in the formula (f) i (Q 0 )=f i (q 10 ,q 20 …q 60 ) (i =1,2 …). And obtaining a solution meeting the calculation precision through repeated approximation and iterative operation.
And 4), designing an anti-interference compensator.
Step 4.1), acquiring angular acceleration information of the actuator by adopting a state observer, and designing a strategy for compensating and controlling disturbance by observing the angular acceleration information on the basis of the angular acceleration information, wherein the design basis is a driving motor torque equation, and a specific expression of the driving motor torque equation is as follows:
angular velocity informationMeasured by a motor encoder, the output torque T of the motor e (T) is an input signal, which is sent to an execution motor by a control command, and the load torque T L And (t) is a disturbance signal and is a variable to be estimated. />
y(t)=Cx(t)
Step 4.3), the system can be completely observed by the observability matrix, so the state observer is designed as follows:
whereinIs an estimate of x (t), G is a state observer gain matrix, which will &>Negative feedback back->Here, the objective is to configure the poles of the observer to improve the dynamic performance such that the error vector of the estimated state and the true state->Approaching 0 as soon as possible.
Step 4.4), the dynamic behavior of the error is:
step 4.5), solving an error equation, wherein a specific expression of the error equation is as follows:
and 4.6) considering the A-GC as a second-order system, and calculating a gain matrix by referring to the optimal parameters of the second-order system.
And 5) based on the above, obtaining the optimal PID control parameter by using a Zieler-Nichols PID parameter diagnosis method.
The invention has the beneficial effects that:
1. the invention comprehensively uses cascade control, an anti-interference compensator and a Zieler-Nichols PID parameter setting method, overcomes the defects of dependence on an accurate mathematical model, complex operation process and the like of the traditional control method, and improves the control precision;
2. the invention uses the cascade control idea to improve the control precision. The invention designs the cascade controller of the inner ring controller based on the hinge space and the outer ring controller based on the hinge space, overcomes the attitude error caused by the coupling between linear actuators, and makes up the defects of the traditional method only applying the controller based on the hinge space;
3. the invention adopts the state observer to acquire the angular acceleration information of the actuator, designs the disturbance compensation control strategy based on the angular acceleration information on the basis, and overcomes the influence of load change on the control precision of the linear actuator.
Drawings
FIG. 1 is a schematic control flow diagram of the process of the present invention.
FIG. 2 is a diagram of the commanded pose for simulation according to the present invention. Where roll represents angle around the x-axis, pitch represents angle around the y-axis, and heave represents displacement along the z-axis.
Fig. 3 is a 6 linear actuator tracking error curve. 0-100s only use a traditional hinge space based PID controller; 100-200s using the cascade controller of the invention, but the anti-interference compensator is closed; 200-300s use the cascade controller and the anti-interference compensator of the invention.
Fig. 4 shows the tracking error curves [ (1), (2) and (3) for the roll, pitch and yaw respectively. 0-100s only use a traditional PID controller based on hinge space; 100-200s using the cascade controller of the invention, but the anti-interference compensator is closed; 200-300s utilize the cascade controller and the anti-interference compensator of the invention.
FIG. 5 is a structure diagram of a six-degree-of-freedom parallel mechanism, which is composed of a motion platform, a static platform, a linear actuator and the like.
Detailed Description
The present invention will be further illustrated with reference to the accompanying drawings and specific embodiments, which are to be understood as merely illustrative of the invention and not as limiting the scope of the invention.
As shown in FIG. 1, the invention discloses a control method of an anti-interference electric six-degree-of-freedom parallel mechanism, which comprises the following steps:
step 1), the actuator researched by the system is a linear guide rail type actuator driven by a permanent magnet synchronous servo motor, the transmission part of the actuator is a ball screw, the screw transmission part is simplified into an ideal model in the system, and the screw transmission part is equivalent to a mathematical model mainly considering the rigidity, the damping and the rotational inertia of the screw transmission part:
step 1.1), obtaining a torque balance equation according to the transmission characteristics of the screw rod, wherein the torque balance equation is as follows:
wherein, J L For the mechanical transmission part, calculating the total moment of inertia of the motor, B L Calculating the total viscous damping coefficient, T, to the motor for the mechanical transmission part L (T) is the load torque, T m (t) is motor output torque, θ L And (t) is the output rotation angle of the screw rod.
Step 1.2), according to a screw stiffness formula, a screw driving torque can be expressed as:
T m =K L [θ e -θ L ] (2)
wherein, T L (t) is the output torque of the motor, K L For converting the mechanical transmission part into the total rotational stiffness, theta, of the output shaft of the linear actuator e (t) is the motor output rotation angle, θ L And (t) is the output rotation angle of the screw rod.
Step 1.3), the relationship between the expansion amount of the linear actuator and the output displacement of the screw shaft is as follows:
wherein, theta L (t) is the motor output rotation angle, P h For transmission lead, X L Is the linear displacement of the screw rod.
The parameters of the electric push rod of a certain model are as follows: b is L =0.35,K L =5364.98N·m/rad,P h =16mm。
And step 2), modeling the permanent magnet synchronous servo motor.
Step 2.1), a driving motor torque model is established, the model adopts a permanent magnet synchronous servo motor, and the torque equation process expression is as follows:
T e (t)=K t i q (t) (5)
wherein, T e (T) is the electromagnetic torque of the machine, T L (t) load torque, J moment of inertia, K t Is a torque constant, i q And (t) is a q-axis stator current. B is the damping coefficient of the motor, theta e And (t) is the output rotation angle of the motor.
And 2.2), establishing a driving motor control model. The servo motor of the system is a speed ring structure, the speed controller is a PI controller, and the current ring is used as an inner ring of the speed ring controller.
Transfer function of closed loop of current loopEquivalent to a first-order inertia element, omega c Current loop bandwidth:
the transfer function of the motor current to the electromagnetic torque is:
MI(s)=K t i q (t) (7)
wherein, K t Is the motor torque constant, i q (t) is a q-axis current.
The electromagnetic torque to motor speed transfer function is:
wherein, J moment of inertia, B damping coefficient.
The digital low pass filter is designed to suppress high frequency noise in the velocity signal with a transfer function of, where f For the filter bandwidth:
the parameters of a motor of a certain model are as follows: j =0.05 kg-cm 2 ,K t =0.9Nm/A,B=0.01Nm·s/rad,ω c =0.02,ω f And =0.01. And step 3), designing a cascade controller. And taking the control based on the hinge point space as an inner ring and taking the control based on the motion platform attitude space as an outer ring. The inner ring controller is a single-input single-output system loop formed by each supporting leg, a PID controller is adopted, and a feedback signal is measured by a linear displacement sensor. The outer ring is compensation control based on an attitude space, the actual measurement attitude is obtained through positive solution to realize the correction of the input attitude, and a PID control method is adopted. The system is positively solved, namely the space attitude of the moving platform is calculated through the length of the supporting leg, a Newton-Raphson iteration method is adopted, and the method comprises the following specific steps:
step 3.1), the distance formula between hinge points of the actuator is as follows:
Δl i =l i -l 0 (11)
wherein l i Is the i-th actuator length, g ki For the coordinates of the points after the moving coordinate system has been transformed into the stationary coordinate system, b ki As a reference frame coordinate point,/ 0 To the initial length of the actuator, Δ l i Corresponding to the expansion amount of the actuator.
And 3.2) solving the moving platform attitude by utilizing linearization processing and a Newton-Raphson iteration method. Obtained from the formulae (10), (11):
obtaining a nonlinear equation system containing six unknowns:
wherein q = [ q ] 1 ,q 2 …q 6 ] T =[x,y,z,α,β,γ] T Which respectively represent six postures of the motion platform.
Step 3.3), solving a nonlinear equation system (9). In the formula f i (q 1 ,q 2 …q 6 ) At point (q) 10 ,q 20 …q 60 ) Performing binary Taylor series expansion on the neighborhood, and obtaining the linear part of the binary Taylor series expansion:
in the formula (f) i (Q 0 )=f i (q 10 ,q 20 …q 60 ) (i =1,2 …). And obtaining a solution meeting the calculation precision through repeated approximation and iterative operation.
And 4), designing an anti-interference compensator.
Step 4.1), acquiring angular acceleration information of the actuator by adopting a state observer, and designing a strategy for compensating and controlling disturbance by observing the angular acceleration information on the basis of the angular acceleration information, wherein the design basis is a driving motor torque equation, and a specific expression of the driving motor torque equation is as follows:
angular velocity informationMeasured by a motor encoder, the output torque T of the motor e (T) is an input signal, which is sent to an execution motor by a control command, and the load torque T L And (t) is a disturbance signal and is a variable to be estimated.
Step 4.3), the system can be completely observed by the observability matrix, so the state observer is designed as follows:
whereinIs x 0 (t) estimation, G 0 For the state observer gain matrix he will &>Negative feedback back->The objective is to configure the poles of the observer to improve dynamic performance such that the error vector of the estimated state and the true state->Approaching 0 as soon as possible.
Step 4.4), the dynamic behavior of the error is:
step 4.5), solving an error equation, wherein a specific expression of the error equation is as follows:
step 4.6), considering the A-GC as a second-order system, referring to the optimal parameters of the second-order system, and designing the bandwidth f by the observer n =112Hz, and damping ratio ξ =0.707. Obtaining a gain matrix G = [959,500000 = [] T 。
And 5) based on the above, obtaining the optimal PID control parameter by applying a Zieler-Nichols PID parameter diagnosis method.
The technical means disclosed in the scheme of the invention are not limited to the technical means disclosed in the above embodiments, but also include the technical means formed by any combination of the above technical features.
Claims (2)
1. An anti-interference electric six-degree-of-freedom parallel mechanism control method is characterized by comprising the following steps:
step 1), the actuator is a linear guide rail type actuator driven by a permanent magnet synchronous servo motor, the transmission part of the actuator is a ball screw, the screw transmission part is simplified into an ideal model, and the screw transmission part is equivalent to a mathematical model considering the rigidity, the damping and the rotational inertia of the screw transmission part:
step 1.1), obtaining a torque balance equation according to the transmission characteristics of the screw rod, wherein the torque balance equation is as follows:
wherein, J L Calculating the total moment of inertia of the motor for the mechanical transmission part, B L Calculating the total viscous damping coefficient, T, to the motor for the mechanical transmission part L (T) is the load torque, T m (t) is motor output torque, θ L (t) is the screw output rotation angle;
step 1.2), according to a screw rod rigidity formula, a screw rod driving torque is expressed as follows:
T m =K L [θ e -θ L ]
wherein, T L (t) is the output torque of the motor, K L For converting the mechanical transmission part into the total rotational stiffness, theta, of the output shaft of the linear actuator e (t) is the motor output rotation angle, θ L (t) is the screw output rotation angle;
step 1.3), the relationship between the expansion amount of the linear actuator and the output displacement of the screw shaft is as follows:
wherein,θ L (t) is the motor output rotation angle, P h For transmission lead, X L Is the linear displacement of the screw rod;
step 2), modeling a permanent magnet synchronous servo motor;
step 2.1), a driving motor torque model is established, the model adopts a permanent magnet synchronous servo motor, and the torque equation process expression is as follows:
T e (t)=K t i q (t)
wherein, T e (T) is the electromagnetic torque of the machine, T L (t) load torque, J moment of inertia, K t Is a torque constant, i q (t) is the q-axis stator current; b is the damping coefficient of the motor, theta e (t) is the motor output rotation angle;
step 2.2), establishing a driving motor control model; the servo motor of the system is a speed ring structure, the speed controller is a PI controller, and a current ring is used as an inner ring of the speed ring controller;
the closed loop transfer function of the current loop is equivalent to a first-order inertia link, omega c Current loop bandwidth:
the transfer function of the motor current to the electromagnetic torque is:
MI(s)=K t i q (t)
wherein, K t Is the motor torque constant, i q (t) is the q-axis current;
the electromagnetic torque to motor speed transfer function is:
j moment of inertia and B damping coefficient;
the digital low pass filter is designed to suppress high frequency noise in the velocity signal with a transfer function of, where f For the filter bandwidth:
step 3), designing a cascade controller; taking control based on a hinge point space as an inner ring and taking control based on a motion platform attitude space as an outer ring; the inner ring controller is a single-input single-output system loop formed by each supporting leg, a PID controller is adopted, and a feedback signal is measured by a linear displacement sensor; the outer ring is compensation control based on an attitude space, the actual measurement attitude is obtained through positive solution to realize the correction of the input attitude, and a PID control method is adopted; the system is positively solved, namely the space attitude of the moving platform is calculated through the length of the supporting leg, and the method adopts a Newton-Raphson iterative method for calculation;
step 4), designing a state observer based on the acceleration information of the actuator, and compensating the external disturbance;
and 5) based on the above, obtaining the optimal PID control parameter by using a Zieler-Nichols PID parameter diagnosis method.
2. The method for controlling the anti-interference electric six-degree-of-freedom parallel mechanism according to claim 1, wherein the detailed steps of the step 4) are as follows:
step 4.1), acquiring angular acceleration information of the actuator by adopting a state observer, and designing a strategy for compensating and controlling disturbance by observing the angular acceleration information on the basis, wherein the design basis is a driving motor torque equation, and the specific expression is as follows:
angular velocity informationMeasured by motor encoderTo obtain the output torque T of the motor e (T) is an input signal, which is sent to an execution motor by a control command, and the load torque T L (t) is a disturbance signal which is a variable to be estimated;
y(t)=Cx(t)
Step 4.3), the system can be completely observed by the observability matrix, so the state observer is designed as follows:
whereinIs an estimate of x (t), G is the state observer gain matrix, which he will ≦>Negative feedback back->The purpose of the method is to configure the pole of the observer, improve the dynamic performance and enable the error vector of the estimated state and the real stateApproaching 0 as soon as possible;
step 4.4), the dynamic behavior of the error is:
step 4.5), solving an error equation, wherein a specific expression of the error equation is as follows:
and 4.6) considering the A-GC as a second-order system, and calculating a gain matrix by referring to the optimal parameters of the second-order system.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202010207104.5A CN111293949B (en) | 2020-03-23 | 2020-03-23 | Control method of anti-interference electric six-degree-of-freedom parallel mechanism |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202010207104.5A CN111293949B (en) | 2020-03-23 | 2020-03-23 | Control method of anti-interference electric six-degree-of-freedom parallel mechanism |
Publications (2)
Publication Number | Publication Date |
---|---|
CN111293949A CN111293949A (en) | 2020-06-16 |
CN111293949B true CN111293949B (en) | 2023-04-11 |
Family
ID=71019810
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN202010207104.5A Active CN111293949B (en) | 2020-03-23 | 2020-03-23 | Control method of anti-interference electric six-degree-of-freedom parallel mechanism |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN111293949B (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104142692A (en) * | 2014-06-26 | 2014-11-12 | 陕西高华知本化工科技有限公司 | Six-degree-of-freedom motion platform |
CN109917657A (en) * | 2019-04-15 | 2019-06-21 | 鲁东大学 | Anti-interference control method, device and the electronic equipment of dynamic positioning ship |
-
2020
- 2020-03-23 CN CN202010207104.5A patent/CN111293949B/en active Active
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104142692A (en) * | 2014-06-26 | 2014-11-12 | 陕西高华知本化工科技有限公司 | Six-degree-of-freedom motion platform |
CN109917657A (en) * | 2019-04-15 | 2019-06-21 | 鲁东大学 | Anti-interference control method, device and the electronic equipment of dynamic positioning ship |
Non-Patent Citations (1)
Title |
---|
陈保秀等.基于优化算法的六自由度气浮台垂向控制.《计算机仿真》.2018,第35卷(第9期),第315-319页. * |
Also Published As
Publication number | Publication date |
---|---|
CN111293949A (en) | 2020-06-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN111152225B (en) | Uncertain mechanical arm fixed time trajectory tracking control method with input saturation | |
CN110531707B (en) | Friction model improvement and dynamic parameter identification method of SCARA robot | |
CN104260107B (en) | The method of a kind of implementation space mechanical arm flexible joint compensation of gear clearance | |
CN109062052A (en) | Quadrotor drone integral sliding mode control method based on extended state observer | |
CN102385342B (en) | Self-adaptation dynamic sliding mode controlling method controlled by virtual axis lathe parallel connection mechanism motion | |
CN110007594B (en) | Self-adaptive robust sliding mode control method of series-parallel robot for automobile electrophoretic coating and conveying | |
CN108762096A (en) | A kind of control-moment gyro frame system Disturbance Rejection method cascading extended state observer based on Discrete Nonlinear | |
CN101846975A (en) | Servo system self-adaptive robust controller with dynamic frictional compensation | |
Wen et al. | The study of model predictive control algorithm based on the force/position control scheme of the 5-DOF redundant actuation parallel robot | |
CN107065562B (en) | Anti-interference synchronous sliding mode control method of series-parallel automobile electrophoretic coating conveying mechanism | |
CN110649845B (en) | Photoelectric turntable position tracking control method based on robust generalized predictive control | |
Deng et al. | Adaptive inverse control for gripper rotating system in heavy-duty manipulators with unknown dead zones | |
CN106100469B (en) | Implementation method based on adaptive motor servo system robust position controller | |
CN108459605A (en) | Trajectory Tracking Control method based on AGV system | |
CN114536334A (en) | High-order sliding mode anti-interference control method for flexible mechanical arm system | |
CN110597051A (en) | Stewart stable platform control method based on RBF neural network | |
CN111673742A (en) | Industrial robot trajectory tracking control algorithm | |
CN112643670A (en) | Flexible joint control method based on sliding-mode observer | |
CN111208735B (en) | Low-switching gain robust super-spiral sliding mode control method for coating conveying mechanism | |
CN111805536A (en) | Self-adaptive sliding mode control method for fruit sorting parallel robot mechanism considering coupling effect | |
CN115576341A (en) | Unmanned aerial vehicle trajectory tracking control method based on function differentiation and adaptive variable gain | |
CN115268369A (en) | Gantry machine tool movable beam cross coupling control method | |
CN114024473B (en) | Anti-interference compound control method of permanent magnet synchronous motor servo system based on backlash compensation | |
Zhao et al. | Backstepping designed sliding mode control for a two-axis tracking system | |
CN111293949B (en) | Control method of anti-interference electric six-degree-of-freedom parallel mechanism |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PB01 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant |