Descriptor modelling towards control link pneumatic robot manipulator A T–S multimodel approach

the first steps towards a robust model-based controller design for two-link manipulators usinga Takagi Sugeno multimodel descriptor form. Due to the circumstances that this form is more similar to a given original nonlinear equation as a Takagi Sugeno multimodel, it allows to reduce the conservatism of the controller design by using common matrix structures. The model-based control law here is equivalent to the well-known parallel distributedcompensation scheme. The challenge of the investigated modelling and control problem in this case is the highly nonlinear dynamics of the dual-actuator drive powered by air-pressure that interacts with the dynamics of the robot manipulator. A rticle Outline1. Introduction2. Physical system modelling2.1. Mechanical model of the manipulator dynamics2.2. Dual-Actuator model3. Reduced physical model in T –S multimodel descriptor form3.1. Reduced actuator model in descriptor form3.2. Model of the manipulator dynamics in T –S multimodel descriptor form3.3. Complete dynamic model in descriptor form4. Experimental validation of the actuator model5. Model-based controller design concept6. Simulation results7. ConclusionAcknowledgementsReferencesPurchase34 Input electrical impedance as quality monitoringsignature for characterizing resistance spotwelding Original Research ArticleNDT & E International , Volume 43, Issue 3, April 2010,Pages 200-205Shih-Fu Ling, Li-Xue Wan, Yoke-Rung Wong, Dong-Neng Li Close preview | Related articles |Related reference w ork articles Abstract | Figures/Tables | ReferencesAbstractPoor quality of resistance spot welding (RSW) often causes quality issues like structural integrity and noise in the car body assembly. Research activities for reliable monitoring methods of RSW quality have therefore been extensive. So far, most of the monitoring methods found in literature are good for off-line utilization only and thus very expensive to apply. This paper introduces into a real-time and in-situ RSW quality monitoring method, which takes the input electrical impedance of the welding system as the monitoring signature. This signature is obtained by probing and processing the input voltage and current throughout the welding process. As input impedance characterizes a dynamic system, its variation with time reveals the conditions of the welding process which result in the final weld quality. By recognizing the pattern of the real part by an artificial neural network, we demonstrate that the weld quality could be classified non-destructively and automatically. Due to the fast signal collecting and processing, the quality monitoring is finished almost in real-time, i.e., classification can be completed before the next welding process is started. Another feature of the method is being in-situ because monitoring action does not jeopardize the welding operation or alter any of the welding parameters in general.A rticle Outline1. Background2. Input impedance as monitoring signaturePurchase3. Experimental study4. Correlation between welding quality and Z in (t ) waveform5.DiscussionsReferences35Optimal manipulator design for a cucumber harvesting robot Original Research ArticleComputers and Electronics in Agriculture ,Volume 65, Issue2, March 2009, Pages 247-257 E.J. Van Henten, D.A. Van‘t Slot, C.W.J. Hol, L.G. Van WilligenburgClose preview | Related articles | Related reference w ork articles Abstract | Figures/Tables | ReferencesAbstractThis paper presents a procedure and the results of an optimal design of the kinematic structure of a manipulator to be used for autonomous cucumber harvesting in greenhouses. The design objective included the time needed to perform a collision-free motion from an initial position to the target position as well as a dexterity measure to allow for motion corrections in the neighborhood of the fruits. The optimisation problem was solved using the DIRECT algorithm implemented in the Tomlab package. A four link PPRR type manipulator was found to be most suitable. For cucumber harves ting four degrees-of-freedom, i.e . three translations and one rotation around the vertical axis, are sufficient. The PPRR manipulator described in this paper meets this requirement. Although computationally expensive, the methodology used in this research was found to be powerful and offered an objective way to evaluate and optimise the kinematic structure of a robot to be used for cucumber harvesting.A rticle Outline1. IntroductionPurchase2. Methodology2.1. Definition of the optimisation problem2.2. Design specification and quantitative evaluation2.2.1. A performance criterion measuring the length of collision-free manipulator motions2.2.2. A performance criterion measuring the dexterity of the manipulator2.2.3. A performance criterion with two weighed objectives2.3. Solution of the optimisation problem3. Results3.1. Case 1—optimisation of the link type of a three link robot3.1.1. The robot work cell and task description3.1.2. Definition of the optimisation problem3.1.3. Results3.2. Case 2—optimisation of three-link PPR, PRR and PRP manipulators for four different tasks3.2.1. The robot work cell and task description3.2.2. Definition of the optimisation problem3.2.3. Results3.3. Case 3—optimisation of a single PRR manipulator design for four different tasks3.3.1. The robot work cell and task description3.3.2. Definition of the optimisation problem3.3.3. Results4. Final discussion and concluding remarks4.1. The manipulator design4.2. The methodologyAcknowledgementsReferences36Design study of an adaptive Fuzzy-PD controller forpneumatic servo system Original Research ArticleControl Engineering Practice, Volume 13, Issue 1, January2005, Pages 55-65Xiang Gao, Zheng-Jin FengClose preview| Related articles | Related reference work articlesAbstract | Figures/Tables | ReferencesAbstractThis paper presents a new adaptive Fuzzy-PD controller and researches theadaptability of the Fuzzy-PD controller for a pneumatic servo position controlsystem which has some typical characteristics of nonlinearity and time-varying.A new control algorithm for friction compensation is introduced to enhance theaccuracy of pneumatic servo position control systems by means of adjustmentof a so-called adaptive controller parameterM a. Some experiments has beenmade to show that the adaptive Fuzzy-PD controller can control the pneumaticservo system accurately.A rticle Outline1. Introduction2. Scheme of a pneumatic servo system for experiment3. Design of a Fuzzy-PD controller for pneumatic servo system3.1. Basic structure of a Fuzzy-PD controller3.2. Design of friction compensator3.3. Adjustment of the scaling factor KΔe4. Experiment results5. ConclusionReferencesPurchase37 Modelling in Modelica and position control of a 1-DoF set-up powered by pneumatic muscles Original Research ArticleMechatronics , Volume 20, Issue 5, August 2010, Pages 535-552Aron Pujana-Arrese, Anjel Mendizabal, Javier Arenas,Ramon Prestamero, Joseba Landaluze Close preview | Related articles | Related reference w ork articles Abstract | Figures/Tables | ReferencesAbstractThe characteristics of pneumatic artificial muscles – or McKibben muscles – make them of great interest for the development of robotic applications such as orthoses or certain wearable robots. In order to research the applicability of these actuators in marketable applications, an experimentalone-degree-of-freedom set-up based on pneumatic muscles manufactured by Festo was built at Ikerlan. After the detailed description of the experimental set-up, the paper presents the modelling of a pneumatic muscle in Modelica as a new component totally compatible with objects from commercial libraries, thus enabling any mechatronic device that contains pneumatic muscles to be modelled. It then offers a description of the experiments performed to identify the model in the case of real pneumatic muscles. With a view to adjusting the static model to the experimental tests, the inclusion of a new polynomial term depending on muscle contraction is proposed by the authors. The paper then shows the complete model of the experimental set-up in Dymola/Modelica. The part related to the modelling ends with a validation of the model withexperimental data. The experimental set-up is very non-linear and very difficult to control properly. As a reference, an enhanced PID controller was designed, and at the same time, a robust controller H ∞ and a sliding-mode controller based on an observer were designed and implemented. After this, a position controller based on an internal pressure loop for each pneumatic muscle was tuned up. The paper goes into detail regarding each of the four position controllersdesigned, and finally, a comparison is made by means of experimental results. PurchaseA rticle Outline1. Introduction2. Description of the 1-DoF experimental set-up3. Pneumatic muscle modelling3.1. Pneumatic muscle static model selection3.2. Static pneumatic muscle model identification experiments3.3. Pneumatic muscle model implementation in Modelica4. Modelling of the 1-DoF experimental set-up4.1. Non-linear modelling of the experimental set-up4.2. Experimental validation of the non-linear model4.3. Linear models of the experimental set-up5. Position controllers5.1. Classic PI and enhanced PID controllers5.2. H∞ controller5.3. Sliding-mode controller5.4. Internal pressure loop based controller6. Experimental results7. ConclusionsAcknowledgementsAppendix A. AppendixReferences38An integrated approach to the conceptual design anddevelopment of an intelligent autonomous mobilerobot Original Research ArticleRobotics and Autonomous Systems, Volume 55, Issue 6, 30June 2007, Pages 498-512Hakan YavuzClose preview| Related articles | Related reference w ork articlesAbstract | Figures/Tables | ReferencesPurchaseAbstractThis paper proposes a new approach to the design and development of an intelligent mobile robot and discusses the complex functional structure of such systems, providing solutions to some typical design problems. The proposed design approach provides a clearer view of the design problems from a function-oriented interdisciplinary point of view. The approach proves to be a useful tool in allowing the designer to cross the boundaries of technical disciplines and optimise the interdisciplinary system‘s components, thereby improving the overall system performance. The paper also presents a case study where it takes the design problem from the most abstract level up to the final stage, in which the developed autonomous mobile robot‘s specifications are verified and validated. The issues address ed in this paper include the design, development, systems integration, and experimental testing of the intelligent mobile robot.A rticle Outline1. Introduction2. Functional analysis of a typical mobile robot3. Proposed design and development process4. Implementation of the proposed design process5. Embodiment of functions5.1. Scheme building5.2. Model simulations6. Systems integration6.1. Functional outline of the system6.2. System integration stages7. Design verification and validation8. Conclusions Acknowledgements ReferencesVitae39 Torque, power requirement and stir zone geometry infriction stir welding through modeling andexperiments Original Research ArticleScripta Materialia, Volume 60, Issue 1, January 2009,Pages 13-16A. Arora, R. Nandan, A.P. Reynolds, T. DebRoyClose preview| Related articles |Related reference w ork articlesAbstract | Figures/Tables | ReferencesThe torque, power requirement and stir zone geometry during friction stirwelding of AA2524 aluminum alloy were modeled by solving the equations ofconservation of mass, momentum and energy. The model predictions agreedwell with the corresponding measured values for a wide range of weldingspeeds and tool rotational speeds when the heat transfer coefficient and thefriction coefficient values were adjusted.A rticle OutlineAcknowledgementsReferencesPurchase40 Validation of dynamic torque response of anelectrorheological (ER) clutch Original Research ArticleMechanical Systems and Signal Processing, Volume 20,Issue 2, February 2006, Pages 463-492K.P. Tan, R. Stanway, W.A. BulloughClose preview| Related articles | Related reference w ork articlesAbstract | Figures/Tables | ReferencesAbstractIt is now well established that using actuators, which have faster speeds ofPurchaseresponse than d.c. servomotors, can solve the positional errors of the robot arms. One of the possible robotic actuators can be an electro-rheological (ER) clutch. To justify this objective, the authors measured the output torque response of a co-axial ER clutch. However, due to the dynamic inefficiency of a torque transducer, the measured torque response is inaccurate for analytical studies. Therefore, this measured torque is signal processed by using the transfer functions of this torque sensor and a filter to yield the ER torque response. The validity of this ER torque is investigated by comparing the numerical errors between the measured torque and its inverse torque response. From the torque error analysis, it is concluded that the ER clutch can be an actuator to improve the positioning accuracies of the robot arms.A rticle Outline1. Introduction2. Experimental apparatus2.1. Basic mechanical arrangement2.2. ER fluid2.3. High-voltage power supply to the ER clutch2.4. ER variables measured3. System identification tests of the torque transducer4. Prediction of ER torque response4.1. Numerical differentiation of the measured torque response4.2. Description of digital filters, the selected filter and its design4.3. Application of time shift compensation to predict ER torque response5. Validation of actual ER torque response6. Conclusions and further workReferences41Characterization of the influences of FSW tool geometryon welding forces and weld tensile strength using an instrumented tool Original Research ArticleJournal of Materials Processing Technology, Volume 203,Issues 1-3, 18 July 2008, Pages 46-57D.G. Hattingh, C. Blignault, T.I. van Niekerk, M.N. JamesClose preview| Related articles | Related reference w ork articlesAbstract | Figures/Tables | ReferencesAbstractFSW process automation is essential to making consistent and reliable frictionstir welds and this requires an understanding of how tool design can influenceprocess parameters, which in turn can provide high joint strength andperformance. Tool optimisation hinges on a better understanding of the effect oftool parameters on forces during welding, on the tool torque and tooltemperature. Important parameters include flute design (e.g. number, depth,and taper angle), the tool pin diameter and taper, and the pitch of any threadform on the pin. These influences were investigated in this study using asystematic tool profile matrix which considered the influence of four variations ofeach of these six geometric factors. Forces on the tool, applied torque andtemperature were monitored and recorded during welding of 6 mm thick5083-H321 aluminium alloy. The lateral reaction forces on each tool and therelative angle of orientation of the peak resultant force are described via abi-lobed polar plot called the ―force footprint‖ (FF). This provides visualinformation on the interaction between tool profile and the plastic stir zone,which cannot be obtained purely from force magnitude information. Keycharacteristics of the tool–weld interaction can be extracted, analysed andsummarized to provide guidance on optimum tool selection for a given set ofweld conditions.A rticle OutlinePurchase1. Introduction2. Overview of the multi-axial transducer and the force footprint (FF)3. Analysing the force footprint4. Number of flutes (A-series tools)5. Flute depth (D-series tools)6. Flute angle (F-series tools)7. Pin taper angle (T-series tools)8. Pin diameter (P-series tools)9.Thread pitch (H-series tools)10. ConclusionsAcknowledgementsReferences42Magnetic torque attitude control of a satellite using thestate-dependent Riccati equation technique OriginalResearch ArticleInternational Journal of Non-Linear Mechanics,Volume 46, Issue 5, June 2011, Pages 758-771Mohammad Abdelrahman, Insu Chang, Sang-Young ParkClose preview| Related articles | Related reference w ork articlesAbstract | Figures/Tables | ReferencesAbstractA non-linear attitude control method for a satellite with magnetic torque rodsusing the state-dependent Riccati equation (SDRE) technique has beendeveloped. The magnetic torque caused by the interaction with the Earth'smagnetic field and the magnetic moment of torque rods plays a role of thecontrol torque. The detailed equations of motion for this system are presentedusing angular velocity and quaternions. The SDRE controller is developed forthe non-linear systems which can be formed in pseudo-linear representationsusing the state-dependent coefficient (SDC) method without linearizationPurchaseprocedure. The aim of this control system is to achieve a stable attitude within 5°, and minimize the control effort. The stability regions for the SDRE controlled satellite system are estimated through the investigation of the stability conditions developed for pseudo-linear systems and the application of Lyapunov's theorem. For comparisons, the Linear Quadratic Regulator (LQR) m ethod using the solution of the algebraic Riccati equation (ARE) is also applied to thisnon-linear system. The performance of the SDRE non-linear control systemdemonstrates more robustness and stability than the LQR control system whensubjected to a wide range of initial conditions.A rticle Outline1. Introduction2. SDRE technique3. Problem statements4. Numerical simulations and discussions5. ConclusionsAcknowledgementsReferences43Multiple-surface sliding controller design for pneumaticservo systems Original Research ArticleMechatronics, Volume 18, Issue 9, November 2008, Pages506-512Yi-Chang Tsai, An-Chyau HuangClose preview| Related articles | Related reference w ork articlesAbstract | Figures/Tables | ReferencesAbstractA multiple-surface sliding controller (MSSC) is proposed for pneumatic servosystems with variable payload and mismatched uncertainties. The system isfirstly modeled by a non-autonomous dynamic equation with consideration of thePurchasevalve dynamics. Various nonlinearities and bounded uncertainties are then lumped into two bounded functions to represent the system equation into a formal form for the design of the MSSC so that the mismatched uncertainties can be properly compensated. The closed loop system is proved to have asymptotically stable performance by using the Lyapunov stability theory. Experimental results show that the proposed algorithm is able to give good performance regardless of the uncertainties and time-varying payload.A rticle Outline1. Introduction2. Modeling of the pneumatic servo system2.1. Proportional valve2.2. Pneumatic cylinder2.3. Payload2.4. State equation of the pneumatic servo system3. Controller design4. Experimental results5. ConclusionsReferences44 Simulating the damage accumulation in aircraft bleed system ducts joined by laser and arc welding processes Original Research ArticleProcedia Engineering, Volume 10, 2011, Pages 1321-1326S.M. Carvalho, C.A.R.P. Baptista, M.S.F. LimaClose pr eview| PDF (694 K) | Related articles | Related reference w ork articles Abstract | ReferencesAbstractThe engine bleed system transports the hot air from the motor to the aircraft systems.Among the various materials suited for use in this system, pure titanium stands out because of its favorable characteristics. The pneumatic system components are subject to cyclic stresses leading to possible failures. The occurrence of fatigue failures in arc welded ducts lead us to develop and test an alternative welding process using a fibre laser of 2 kW in order to join titanium components for the aircraft bleed system. The lower thermal input ofthis process results in reduced dimensions of the weld beads and lower residual stressesand distortions when compared to the conventional arc welding. During the weldingdevelopment stage, the best results were obtained at 200 W for a welding speed of 2 m/min.In order to assess the performance of welded joints, cyclic pressurization tests at theworking temperature of 350 °C and maximum pressure of 150 psi were conducted in thepneumatic workbench aimed at simulating the aging process suffered by the pneumaticsystem ducts. The microstructure and mechanical properties of the specimens weredetermined and the performances of laser beam and arc welded joints were compared.45The influence of welding parameters on the jointstrength of resistance spot-welded titaniumsheets Original Research ArticleMaterials & Design, Volume 28, Issue 2, 2007, Pages420-427Nizamettin KahramanClose preview| Related articles |Related reference w ork articlesAbstract | Figures/Tables | ReferencesAbstractIn this study, commercially pure (CP) titanium sheets (ASTM Grade 2) werewelded by resistance spot welding at different welding parameters and underdifferent welding environments. The welded joints were subjected totensile-shearing tests in order to determine the strength of the welded zones. Inaddition, hardness and microstructural examinations were carried out in order toexamine the influence of welding parameters on the welded joints. The resultsshowed that increasing current time and electrode force increased the tensilePurchaseshearing strength and the joints obtained under the argon atmosphere gave better tensile-shearing strength. Hardness measurement results indicated that welding nugget gave the highest hardness and the heat affected zone (HAZ) and the base metal followed this. The argon gas used during the welding process was seen to have no influence on the hardness values. Microstructural examinations revealed that the deformations took place in the welding zone during welding. The twinning took place in the grains. High electrode force andhigh weld cycles, were used during the welding, increased the twinning.A rticle Outline1. Introduction2. Experimental prodecure3. Results and discussion3.1. Tensile-shearing test3.2. Hardness measurement3.3. Microstructure4. ConclusionAcknowledgementsReferences46Mixed-reality environment for frictional parametersidentification in servo-pneumatic system OriginalResearch ArticleSimulation Modelling Practice and Theory, Volume 17,Issue 10, November 2009, Pages 1575-1586A. Saleem, C.B. Wong, J. Pu, P.R. MooreClose preview| Related articles | Related reference w ork articlesAbstract | Figures/Tables | ReferencesAbstractThis paper outlines a method to identify the friction parameters forPurchaseservo-pneumatic systems using a mixed-reality environment. To acquire system friction parameters accurately can be extremely difficult once the servo-system has been assembled because of its highly nonlinear nature, which causes a great difficulty in servo-pneumatic system modelling and control. In this research, a mixed-reality environment has been employed to determine the friction parameters effectively and efficiently through online identification. Traditionally, friction parameters identification can be performed manually or automatically using traditional optimization methods or modern ones such as neural networks. The advantages of the proposed method are the high accuracy in the estimated parameters, its simplicity and its speed. An experimental case study has been conducted and the results showed the accuracy and effectiveness of the proposed method.A rticle OutlineNomenclature1. Introduction2. Component-based modelling2.1. Valve module2.2. Tubing module2.3. Actuator module2.4. Load module3. Component-based simulation approach4. ―Mixed-reality‖ environment for friction parameters identification4.1. Experimental setup4.2. Simulation environment4.3. Friction parameters identification method5. Case study: PIDVF controller scheme6. Conclusions and future workReferences47Speed sensorless direct torque control of IMs with rotor resistance estimation Original Research ArticleEnergy Conversion and Management, Volume 46, Issue 3, February 2005, Pages 335-349Murat Barut, Seta Bogosyan, Metin GokasanClose preview| Related articles | Related reference w ork articlesAbstract | Figures/Tables | ReferencesAbstractDirect torque control (DTC) of induction motors (IMs) requires an accurateknowledge on the amplitude and angular position of the controlled flux inaddition to the information related to angular velocity for velocity controlapplications. However, unknown load torque and uncertainties related tostator/rotor resistances due to operating conditions constitute major challengesfor the performance of such systems. The determination of stator resistance canbe performed by measurements, but methods must be developed for estimationand identification of rotor resistance and load torque. In this study, an EKFbased solution is sought for determination of the rotor resistance and loadtorque as well as the above mentioned states required for DTC. The EKFalgorithm used in conjunction with the speed sensorless DTC is tested undereleven scenarios comprised of various changes made in the velocity referencebeside the load torque and rotor resistance values assigned in the model. Withno a priori information in the estimated states and parameters, it has beendemonstrated that the EKF estimation and sensorless DTC perform quite well inspite of the uncertainties and variations imposed on the system.A rticle Outline1. Introduction2. Extended mathematical model of the IMPurchase3. Development of the EKF algorithm4. Speed sensorless DTC system5. Simulation results and observations 5.1. Observations5.1.1. Operation under constantand constant/linear velocity references 5.1.2. Operation under linear and constant/linear velocity references5.1.3. Operation in the low velocity region, with no load references5.1.4. Operation with linear velocity reference and linear tL5.1.5. Operation under reversal of velocity reference5.1.6. Operation under R r ′=2R r n ′ (constant velocity reference/load torque)5.1.7. Uncertainties captured in constant t L6. ConclusionAcknowledgementsReferences48 Bi-bellows: Pneumatic bending actuator Original Research ArticleSensors and Actuators A: Physical , Volume 167, Issue 2,June 2011, Pages 484-494Yoel Shapiro, Alon Wolf, Kosa GaborClose preview | Related articles | Related reference w ork articles Abstract | Figures/Tables | ReferencesAbstractWe present a compliant single degree-of-freedom pneumatic actuator with large bending capabilities. Several actuator designs are compared and validatedagainst the suggested actuation model. Repeatability, some dynamic properties and the affect of external loads are examined as well.A rticle Outline1. IntroductionPurchase。