CN111796525A - Model prediction control method based on exoskeleton robot mechanical arm - Google Patents
Model prediction control method based on exoskeleton robot mechanical arm Download PDFInfo
- Publication number
- CN111796525A CN111796525A CN202010889859.8A CN202010889859A CN111796525A CN 111796525 A CN111796525 A CN 111796525A CN 202010889859 A CN202010889859 A CN 202010889859A CN 111796525 A CN111796525 A CN 111796525A
- Authority
- CN
- China
- Prior art keywords
- tracking error
- exoskeleton robot
- mechanical arm
- follows
- robot mechanical
- 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.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 41
- 238000005096 rolling process Methods 0.000 claims abstract description 6
- 238000005457 optimization Methods 0.000 claims abstract description 5
- 230000033001 locomotion Effects 0.000 claims description 11
- 230000005540 biological transmission Effects 0.000 claims description 6
- 239000011159 matrix material Substances 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 4
- 230000001133 acceleration Effects 0.000 claims description 3
- 230000005484 gravity Effects 0.000 claims 1
- 230000000694 effects Effects 0.000 description 4
- 210000003141 lower extremity Anatomy 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000000418 atomic force spectrum Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 210000000689 upper leg Anatomy 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B13/00—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion
- G05B13/02—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric
- G05B13/04—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric involving the use of models or simulators
- G05B13/048—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric involving the use of models or simulators using a predictor
Landscapes
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Artificial Intelligence (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Evolutionary Computation (AREA)
- Medical Informatics (AREA)
- Software Systems (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Feedback Control In General (AREA)
Abstract
The invention discloses a model prediction control method based on an exoskeleton robot mechanical arm, and belongs to the field of exoskeleton robots. Aiming at the problem of overlarge steady-state error under the condition of time-varying disturbance and parameter uncertainty in the prior art, the invention provides a model prediction control method based on an exoskeleton robot mechanical arm, which comprises the following steps: firstly, a high-gain observer based on continuous time is provided for estimating the state and disturbance of a tracking error; then, an improved performance index is provided, which comprises a tracking error part and a control input part; and finally, obtaining a model predictive control law after the performance indexes are subjected to rolling time domain optimization. The method can meet the requirement of optimal non-offset tracking, has better steady-state performance under the condition of time-varying disturbance, and is easy to realize.
Description
Technical Field
The invention relates to the field of exoskeleton robots, in particular to a model prediction control method of a mechanical arm of an exoskeleton robot.
Background
The exoskeleton robot technology is a comprehensive technology which integrates sensing, control, information, fusion and mobile computing and provides a wearable mechanical mechanism for a person as an operator. Exoskeleton robots can find full application in civilian, military and commercial areas, for example: the walking aid can assist people with physical disabilities to walk in the civil aspect, and can assist soldiers to fight in the military aspect, and the like. Due to the complexity of the mechanical structure of the exoskeleton robot and the influence of various parameters such as friction force, accurate values of the parameters of the exoskeleton robot are difficult to obtain.
Chinese patent application, publication No. CN105955015A, published 2016, 9, 21, discloses a fuzzy control method for exoskeleton systems. The method is designed aiming at the conditions that the traditional exoskeleton is easily influenced by the external environment when the PID control is mostly adopted, and the control effect of the system is poor. After the control model is changed, the controller can better track an expected curve compared with PID (proportion integration differentiation) in fuzzy self-adaptive control, and has obvious advantages in the aspects of instantaneity, robustness and the like. But the fuzzy control rule of the method is complex and is not easy to realize.
The Chinese patent application, application No. CN105796286B, published 2016, 7, 27, discloses a control method based on a lower limb exoskeleton robot, which adds an air bag pressure sensor on the basis of a traditional lower limb exoskeleton human intention detection sensor, and reflects the acting force of a human body and an exoskeleton by measuring a signal generated by pressing an air bag by a thigh of the human body, thereby feeding back the human body movement intention and correcting the deviation of an exoskeleton control algorithm; the air bag sensor is used, and meanwhile, a flexible human-computer interface can be provided for a human body, so that the acting force of the human body and the exoskeleton robot is buffered; meanwhile, the assistance effect of the lower limb exoskeleton robot can be better evaluated by collecting the motion curve of the human body wearing the exoskeleton and the force curve of the airbag sensor. The method corrects the offset by a fuzzy controller. However, the fuzzy rule of the method is complex to make and is not easy to realize depending on expert experience.
Disclosure of Invention
1. Technical problem to be solved
Aiming at the problem of overlarge steady-state error under the conditions of time-varying disturbance and parameter uncertainty in the prior art, the invention provides a model prediction control method based on an exoskeleton robot mechanical arm, which can meet the requirement of optimal non-offset tracking, ensures better dynamic stability and is easy to realize.
2. Technical scheme
The purpose of the invention is realized by the following technical scheme.
A model prediction control method based on an exoskeleton robot mechanical arm comprises the following steps:
step 1: providing an improved performance index which comprises a tracking error part and a control input part;
step 2: providing a high-gain observer based on continuous time, and estimating the state and disturbance of a tracking error;
and step 3: and (3) combining the errors and the disturbances in the step (2), and obtaining a model predictive control law after the performance indexes in the step (1) are subjected to rolling time domain optimization.
Further, in the step 1, the method comprises the following steps:
step 101, providing a mechanical arm motion control system equation of the exoskeleton robot:
wherein u is the moment generated on the actuator shaft, d is the disturbance moment on the link shaft, and q is1To perform angular positions on the shaft, q2Angular position of the connecting rod, J1Is the moment of inertia of the actuator, J2Is the moment of inertia of the connecting rod, F1Is the coefficient of friction of the actuator, F2Is the friction coefficient of the connecting rod, K is the spring elastic coefficient, N is the transmission ratio of the transmission gear, m is the connecting rod mass, l is the connecting rod length, and g is the gravitational acceleration;
step 102, a dynamic tracking error equation of a mechanical arm motion system of the exoskeleton robot is given:
wherein q is2r(t) is a reference output signal,is a set of positive integers, b0Is the nominal value of b (t), b (t) is controlAnd (5) making a gain. e (t) is the error of the actual output from the reference output, w (t) is the sum of various unknown disturbances and uncertainties, w4(t) contains a known reference output;
step 103, providing performance indexes of a mechanical arm motion control system equation based on the exoskeleton robot:
wherein: t: (>0) Is the prediction period; u. ofr(t) is the desired steady state control input,is the weight of the tracking error; r (R)>0) Is the weight of the controller input.
Further, in the step 2, the continuous-time based high-gain observer is:
wherein the content of the first and second substances,andare all generated by an observer,/i,σiAnd τ is the adjustable observer gain.
Further, the method of estimating the tracking error system is as follows:
in step 201, a tracking error e (T + τ) at a future time is given in a prediction period T, and after taylor series expansion, the tracking error e (T + τ) can be expressed as follows:
where 0. ltoreq. tau. ltoreq.T, simply by symbolizing the estimated values of the variablesIndicating that the predicted value of the variable is signedRepresents;
in step 202, the estimated value generated by the disturbance observer is represented asThe predicted tracking error can be expressed in the form:
the control input is represented in the form:
the predicted tracking error can be expressed in the form:
wherein:
step 203, the controller input and the expected controller input at the future time are given as follows:
wherein the vectorThe method is used for correcting the interference and uncertainty existing in the traditional Taylor series expansion prediction method.
Further, combining the formulas (6), (7) and (8), the performance index in the formula (3) is rewritten as follows:
further, the process of obtaining the model predictive control law after the performance index is optimized in a rolling time domain is as follows:
will be in the formula (9)To pairCalculating the partial derivative to obtain:knowing matrixIs a positive definite matrix. Order toThe optimized control output is obtained as follows:
the model predictive control law is given in conjunction with equation (10) as follows:
To meet the practical application, the estimated valueAndare generated by an observer. And the following assumptions must be satisfied: there is a known constant L ≧ 0, m ∈ N+I.e. | w(m)(t)|≤L。
3. Advantageous effects
Compared with the prior art, the invention has the advantages that: the invention designs a continuous time model prediction control system method based on an exoskeleton robot, and by designing a model prediction control method with a nonlinear disturbance observer, optimal offset-free tracking can be realized under various disturbances. Compared with the traditional model prediction control law, the method has better steady-state performance under the condition of time-varying disturbance; meanwhile, the method provides a new performance index, and definitely analyzes the influence of the control input weight on the stability of the closed loop.
Drawings
FIG. 1 is a block diagram of a model predictive control method implementation proposed by the present invention;
FIG. 2 is a schematic view of an exoskeleton-based robotic arm;
FIG. 3 is a graph of q in the case of system uncertainty and external interference2The output curve of (a);
FIG. 4 is q of FIG. 3 after enlargement in 0-15 seconds2The output curve of (1).
Detailed Description
The invention is described in detail below with reference to the drawings and specific examples.
Examples
As shown in fig. 1, the invention discloses a model prediction control method for an exoskeleton robot mechanical arm, comprising the following steps:
step 1: the improved performance index comprises a tracking error part and a control input part, and comprises the following specific steps:
step 101, a motion control system equation of a mechanical arm of the exoskeleton robot is given:
as shown in fig. 2, in the schematic diagram of the exoskeleton robot mechanical arm, u is the moment generated on the actuator shaft, d is the disturbance moment on the link shaft, and q is1To perform angular positions on the shaft, q2Angular position of the connecting rod, J1Is the moment of inertia of the actuator, J2Is the moment of inertia of the connecting rod, F1Is the coefficient of friction of the actuator, F2Is the friction coefficient of the connecting rod, K is the spring elastic coefficient, N is the transmission ratio of the transmission gear, m is the connecting rod mass, l is the connecting rod length, and g is the gravitational acceleration;
step 102, a dynamic tracking error equation of a mechanical arm motion system of the exoskeleton robot is given:
wherein q is2r(t) is a reference output signal,is a set of positive integers, b0Is the nominal value of b (t), b (t) is the control gain, e (t) is the error of the actual output from the reference output, w (t) is the sum of various unknown disturbances and uncertainties, w (t) is the sum of the various unknown disturbances and uncertainties4(t) contains a known reference output;
step 103, providing performance indexes of a motion control system equation based on the mechanical arm of the exoskeleton robot:
wherein T: (>0) Is the prediction period; u. ofr(t) is the desired steady state control input,Q(>0) is a weight of the tracking error, R: (>0) Is the weight of the controller input.
Step 2: designing a high-gain observer based on continuous time to estimate the state and disturbance of a tracking error, and specifically comprising the following steps of:
first, a continuous-time based high-gain observer is given:
wherein the content of the first and second substances,andare all generated by an observer,/i,σiAnd τ is the adjustable observer gain.
Next, the method of estimating the tracking error system is as follows:
step 201, a tracking error e (T + τ) at a future time is given in a prediction period T, and after Taylor series expansion, the tracking error e (T + τ) can be expressed in the following form
Where 0. ltoreq. tau. ltoreq.T, simply by symbolizing the estimated values of the variablesIndicating that the predicted value of the variable is signedRepresents;
in step 202, the estimated value generated by the disturbance observer is represented asThe predicted tracking error can be expressed in the form:
the control input is represented in the form:
the predicted tracking error can be expressed in the form:
wherein:
step 203, the controller input and the expected controller input at the future time are given as follows:
wherein the vectorThe method is used for correcting the interference and uncertainty existing in the traditional Taylor series expansion prediction method.
And 3, combining the errors and the disturbances in the step 2, and obtaining a model predictive control law after the performance indexes are subjected to rolling time domain optimization, wherein the method specifically comprises the following steps:
first, the performance index in the formula (3) is rewritten in the following form in combination with the formulas (6), (7), and (8):
finally, the method for obtaining the model predictive control law after the performance indexes are optimized by the rolling time domain is as follows:
knowing matrixIs a positive definite matrix. Order toThe optimized control output is obtained as follows:
the model predictive control law is given in conjunction with equation (10) as follows:
To meet the practical application, the estimated valueAndare generated by an observer. And the following assumptions must be satisfied: there is a known constant L ≧ 0, m ∈ N+I.e. | w(m)(t)|≤L。
As shown in fig. 3 and 4, q in case of system uncertainty and external interference2The dotted line, the broken line and the dotted line represent that the system parameters have values of 10%, 20% and 30%, respectivelyUncertainty, black line is a parameter of the actual system. It can be seen from the figure that the output can be quickly restored to the set value even under the conditions of uncertainty and interference, and the excellent effect of the method is reflected.
The invention and its embodiments have been described above schematically, without limitation, and the invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The representation in the drawings is only one of the embodiments of the invention, the actual construction is not limited thereto, and any reference signs in the claims shall not limit the claims concerned. Therefore, if a person skilled in the art receives the teachings of the present invention, without inventive design, a similar structure and an embodiment to the above technical solution should be covered by the protection scope of the present patent. Furthermore, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. Several of the elements recited in the product claims may also be implemented by one element in software or hardware. The terms first, second, etc. are used to denote names, but not any particular order.
Claims (6)
1. A model prediction control method based on an exoskeleton robot mechanical arm is characterized by comprising the following steps:
step 1: providing an improved performance index which comprises a tracking error part and a control input part;
step 2: a high-gain observer based on continuous time is provided, and the state and disturbance of a tracking error system are estimated;
and step 3: and (3) combining the errors and the disturbances in the step (2), and obtaining a model predictive control law after the performance indexes in the step (1) are subjected to rolling time domain optimization.
2. The method for model predictive control based on exoskeleton robot mechanical arms as claimed in claim 1, wherein the step 1 comprises the following steps:
step 101, providing a mechanical arm motion control system equation of the exoskeleton robot:
wherein u is the moment generated on the actuator shaft, d is the disturbance moment on the link shaft, and q is1To perform angular positions on the shaft, q2Angular position of the connecting rod, J1Is the moment of inertia of the actuator, J2Is the moment of inertia of the connecting rod, F1Is the coefficient of friction of the actuator, F2The friction coefficient of the connecting rod, K is the elastic coefficient of the spring, N is the transmission ratio of the transmission gear, m is the mass of the connecting rod, 1 is the length of the connecting rod, and g is the gravity acceleration;
step 102, providing a dynamic tracking error equation of the exoskeleton robot mechanical arm motion system:
wherein q is2r(t) is a reference output signal,is a set of positive integers, b0Is the nominal value of b (t), b (t) is the control gain, e (t) is the error of the actual output from the reference output, w (t) is the sum of various unknown disturbances and uncertainties, w (t) is the sum of the various unknown disturbances and uncertainties4(t) contains a known reference output;
step 103, providing performance indexes of the motion control system equation of the exoskeleton robot mechanical arm:
4. The method for model predictive control based on exoskeleton robot mechanical arms as claimed in claim 1 wherein in step 2, the method for estimating the tracking error system is as follows:
in step 201, a tracking error e (T + τ) at a future time is given in a prediction period T, and after taylor series expansion, the tracking error e (T + τ) can be expressed as follows:
where 0 is more than or equal to tau is less than or equal to T, and the estimated value of the variable is signedIndicating that the predicted value of the variable is signedRepresents;
in step 202, the estimated value generated by the disturbance observer is represented asThe predicted tracking error can be expressed in the form:
the control input is represented in the form:
the predicted tracking error can be expressed in the form:
wherein:
step 203, the controller input and the expected controller input at the future time are given as follows:
6. the method for model predictive control based on an exoskeleton robot mechanical arm as claimed in claim 1, wherein in step 3, the method for obtaining the model predictive control law after optimization is as follows:
matrix arrayIs a positive definite matrix, such thatThe optimized control output is obtained as follows:
the model predictive control law is given in conjunction with equation (10) as follows:
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202010889859.8A CN111796525B (en) | 2020-08-28 | 2020-08-28 | Model prediction control method based on exoskeleton robot mechanical arm |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202010889859.8A CN111796525B (en) | 2020-08-28 | 2020-08-28 | Model prediction control method based on exoskeleton robot mechanical arm |
Publications (2)
Publication Number | Publication Date |
---|---|
CN111796525A true CN111796525A (en) | 2020-10-20 |
CN111796525B CN111796525B (en) | 2022-12-02 |
Family
ID=72834459
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN202010889859.8A Active CN111796525B (en) | 2020-08-28 | 2020-08-28 | Model prediction control method based on exoskeleton robot mechanical arm |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN111796525B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114721258A (en) * | 2022-02-21 | 2022-07-08 | 电子科技大学 | Lower limb exoskeleton backstepping control method based on nonlinear extended state observer |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109648564A (en) * | 2019-01-15 | 2019-04-19 | 西安科技大学 | A kind of control method of the multiple degrees of freedom flexible articulated mechanical arm system based on hierarchical structure MPC |
CN111152225A (en) * | 2020-01-15 | 2020-05-15 | 北京科技大学 | Uncertain mechanical arm fixed time trajectory tracking control method with input saturation |
CN111290273A (en) * | 2020-02-18 | 2020-06-16 | 湖州和力机器人智能科技有限公司 | Position tracking optimization control method based on exoskeleton robot flexible actuator |
-
2020
- 2020-08-28 CN CN202010889859.8A patent/CN111796525B/en active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109648564A (en) * | 2019-01-15 | 2019-04-19 | 西安科技大学 | A kind of control method of the multiple degrees of freedom flexible articulated mechanical arm system based on hierarchical structure MPC |
CN111152225A (en) * | 2020-01-15 | 2020-05-15 | 北京科技大学 | Uncertain mechanical arm fixed time trajectory tracking control method with input saturation |
CN111290273A (en) * | 2020-02-18 | 2020-06-16 | 湖州和力机器人智能科技有限公司 | Position tracking optimization control method based on exoskeleton robot flexible actuator |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114721258A (en) * | 2022-02-21 | 2022-07-08 | 电子科技大学 | Lower limb exoskeleton backstepping control method based on nonlinear extended state observer |
CN114721258B (en) * | 2022-02-21 | 2023-03-10 | 电子科技大学 | Lower limb exoskeleton backstepping control method based on nonlinear extended state observer |
Also Published As
Publication number | Publication date |
---|---|
CN111796525B (en) | 2022-12-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN111281743B (en) | Self-adaptive flexible control method for exoskeleton robot for upper limb rehabilitation | |
JP7375754B2 (en) | Control device, control method, and control system | |
Jin et al. | The adaptive Kalman filter based on fuzzy logic for inertial motion capture system | |
US20120109872A1 (en) | Wireless motion sensor network for monitoring motion in a process, wireless sensor node, reasoning node, and feedback and/or actuation node for such wireless motion sensor network | |
CN110877333A (en) | Flexible joint mechanical arm control method | |
Musavi et al. | Adaptive fuzzy neuro-observer applied to low cost INS/GPS | |
CN111496796B (en) | Mechanical arm trajectory tracking control method and device based on instruction filter | |
CN111796525B (en) | Model prediction control method based on exoskeleton robot mechanical arm | |
CN111781841B (en) | Limited time model prediction control method based on exoskeleton robot | |
Asad et al. | Backstepping-based recurrent type-2 fuzzy sliding mode control for MIMO systems (MEMS triaxial gyroscope case study) | |
CN111716360B (en) | Fuzzy logic-based flexible joint mechanical arm sampling control method and device | |
CN111856945B (en) | Lower limb exoskeleton sliding mode control method based on periodic event trigger mechanism | |
Kuzdeuov et al. | Neural network augmented sensor fusion for pose estimation of tensegrity manipulators | |
CN112621714A (en) | Upper limb exoskeleton robot control method and device based on LSTM neural network | |
Bae et al. | Biped robot state estimation using compliant inverted pendulum model | |
Huo et al. | Impedance modulation control of a lower-limb exoskeleton to assist sit-to-stand movements | |
CN105912013A (en) | Model-free self-adaptive control method for attitude of assembled spacecraft | |
CN112008726B (en) | Composite finite time control method based on exoskeleton robot actuator | |
CN111965979B (en) | Limited time control method based on exoskeleton robot actuator | |
CN112947123B (en) | Exoskeleton robot tracking control method and system for inhibiting multi-source interference | |
Wang et al. | Neural network predictive control of swing phase for a variable-damping knee prosthesis with novel hydraulic valve | |
CN111403019B (en) | Method for establishing ankle joint artificial limb model, model-free control method and verification method | |
Chiou et al. | A Novel Wearable Upper-Limb Rehabilitation Assistance Exoskeleton System Driven by Fluidic Muscle Actuators | |
CN111983925A (en) | Generalized dynamic prediction control method based on exoskeleton robot | |
Ding et al. | Robust and Safe Control of a Knee Joint Orthosis |
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 |