Accepted Manuscripts

Technical Brief  
Tomas Poloni, Ilya Kolmanovsky and Boris Rohal-Ilkiv
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037298
In this paper, the application of an Input Disturbance Observer-based (IDO) control, based on a simple input observer previously proposed and used for engine control, is demonstrated in two case studies. The first case study is longitudinal aircraft control with unmodeled aerodynamic nonlinearities satisfying matching conditions. The second case study is the control of an inverted pendulum on a cart which corroborates the ease of integration of IDO-based control into more complex controllers in situations when the matching condition is not satisfied. Improved robustness is demonstrated on an experimental system including changing the pendulum weight which is shown to have no effect on the overall control performance. In both case studies if the IDO is not applied the control performance is poor and leads to unstable operation.
TOPICS: Weight (Mass), Control equipment, Engines, Aircraft, Pendulums, Robustness
Alireza Mousavi, Amir Hossein Davaie Markazi and Saleh Masoudi
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037296
A novel application of the Adaptive Fuzzy Sliding-Mode Control (AFSMC) to the case of an Antilock Braking System (ABS) is proposed in this paper. ABS is a system in vehicles that allows the wheels to maintain tractive contact with the road and avoid uncontrolled skidding. By using ABS, the stopping distances on dry and slippery surfaces are expected to decrease. The maximum braking force is a nonlinear function of the slip ratios of the wheels, which is sensitive to the vehicle weight and road condition. In this research, a simple low-order model of the braking dynamics is considered and un-modeled dynamics are taken as uncertainties. The robust AFSMC method is used to regulate the wheel slip ratio towards the desired value. The proposed controller employs Pulse Width Modulation (PWM) to generate the braking torque. There is no need to use any reference measured data or experimental knowledge of relevant experts to design the controller. A clear advantage is that the designed controller does not rely on the nonlinear tire-road friction model. The second Lyapunov theorem is employed to prove the closed-loop asymptotic stability. In the simulations, the multi-body dynamics method is used for modeling the longitudinal motion of SAIPA X100 and X200 vehicle platforms. Furthermore, the actuation and the switching dynamics of the braking system are taken into account. Resulting performance is compared to the conventional sliding-mode and feedback linearization methods. Analysis on the simulation results reveal the effectiveness of proposed AFSMC method.
TOPICS: Control equipment, Antilock braking systems, Dynamics (Mechanics), Braking, Roads, Wheels, Vehicles, Uncertainty, Simulation results, Tires, Feedback, Pulse width modulation, Theorems (Mathematics), Weight (Mass), Torque, Stability, Friction, Simulation, Design, Engineering simulation, Modeling
Yujiang Qiu and Shuyun Jiang
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037297
Developing a flywheel energy storage system (FESS) with permanent magnetic bearing (PMB) and spiral groove bearing (SGB) brings a great challenge to dynamic control for the rotor system. In this technical brief, a pendulum tuned mass damper is developed for 100 kg-class FESS to suppress low-frequency vibration of system; the dynamic model with four degrees of freedom is built for the FESS using Lagrange's theorem; mode characteristics, critical speeds and Unbalance responses of the system are analyzed via theory and experiment. A comparison between the theoretical results and the experiment shows that the pendulum tuned mass damper is effective, the dynamic model is appropriate, and the FESS can run smoothly within the working speed range.
TOPICS: Dynamics (Mechanics), Flywheels, Bearings, Energy storage, Magnetic bearings, Pendulums, Dynamic models, Dampers, Degrees of freedom, Rotors, Vibration, Theorems (Mathematics)
Review Article  
Sanath Alahakoon, Yan Sun, Maksym Spiryagin and Colin Cole
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037295
This paper delivers an in-depth review of the state-of-the-art of the technologies relevant to rail flaw detection giving emphasis to their use in detection of rail flaw defects at practical inspection vehicle speeds. The review not only looks at the research being carried out, but also investigates the commercial products available for rail flaw detection and their applicability for a moving vehicle rail flaw detection system. It continues further to identify the methods suitable to be adopted in a moving vehicle rail flaw detection system. Even though rail flaw detection has been a well-researched area for decades, an in-depth review summarizing all available technologies together with an assessment of their capabilities has not been published in the recent past according to the knowledge of the authors. As such, it is believed that this review paper will be a good source of information for future researchers in this area.
TOPICS: Transportation systems, Flaw detection, Rails, Vehicles, Inspection
Huan Li, Ying Huang, Guoming George Zhu and Zheng Lou
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037286
This paper presents a novel linear parameter-varying (LPV) model of an electro-hydraulic variable valve actuator for internal combustion engines that is capable of continuously varying valve timing with dual-lift. The dual-lift is realized mechanically through a hydraulic lift control sleeve; valve opening terminal and closing seating velocities are regulated using a top or bottom snubber; and opening and closing timings, as well as lift profile area, are controlled by the valve actuation timing and hydraulic supply pressure. First, nonlinear mathematical system model is developed based on the Newton's law, orifice flow equation, and fluid constitutive law, where the fluid dynamics of the actuation solenoid valve, actuation piston, passages, and orifices, that influence the engine valve profile, are considered in detail. Second, to have an LPV control-oriented model, the order of nonlinear model is reduced and subsequently transformed into an LPV model with minimal deviation by carefully considering the system nonlinearities, time delay, and time-varying parameters. Calibration and validation experiments for both nonlinear and LPV models were performed on the test bench under different operational conditions. The key time-varying parameters, the time constant of the actuation piston top pressure and the discharge coefficient, are highly nonlinear as functions of temperature-sensitive fluid viscosity and are determined using the test data through the Least-Squares optimization. With the identified and calibrated model parameters, simulation results of both nonlinear and LPV models are in good agreement with the experimental ones under different operational conditions.
TOPICS: Valve actuators, Internal combustion engines, Valves, Pistons, Fluids, Pressure, Fluid dynamics, Flow (Dynamics), Temperature, Viscosity, Engines, Hydraulic lifts, Constitutive equations, Simulation results, Solenoids, Optimization, Calibration, Delays, Discharge coefficient, Orifices
Tao Song, Fengfeng Xi, Shuai Guo, Xiao Wei Tu and Xianhua Li
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037287
A method is presented for slip analysis of a wheeled mobile manipulator. The said system consists of an industrial manipulator mounted on a mobile platform performing aircraft manufacturing tasks. Unlike tracked/legged mobile robots that may slip when negotiating slopes or climbing stairs, a wheeled mobile manipulator may slip resulting from the manipulator movement or the forces from the end-effector during riveting. Slip analysis is crucial to ensure operation pose accuracy. In this study, first a universal friction constraint is used to derive the slip condition of the system. Three cases are considered, with the first case considering the reaction force in relation to the stand-off distance between the mobile manipulator and the work piece. The second case deals with the joint speeds to investigate the effect of coupling terms including centrifugal forces and gyroscopic moments on slip. The third case deals with the joint accelerations to investigate the effect of inertia forces and moments on slip. Simulations and experiments are carried out to verify the proposed method.
TOPICS: Manipulators, Mobile robots, Riveting, Inertia (Mechanics), Friction, Stairs, Manufacturing, Centrifugal force, Simulation, Engineering simulation, Aircraft, End effectors
Technical Brief  
Sihan Xiong, Sudeepta Mondal and Dr. Asok Ray
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037288
Real-time detection and decision & control of thermoacoustic instabilities in confined combustors is a challenging task due to the fast dynamics of the underlying physical process. The objective here is to develop a dynamic data-driven algorithm for detecting the onset of instabilities with short-length time series data, acquired by available sensors (e.g., pressure and chemiluminescence), which will provide sufficient lead time for active decision & control. To this end, this paper proposes a Bayesian nonparametric method of Markov modeling for real-time detection of thermoacoustic instabilities in gas turbine engines; the underlying algorithms are formulated in the symbolic domain and the resulting patterns are constructed from symbolized pressure measurements as probabilistic finite state automata (PFSA). These PFSA models are built upon the framework of a (low-order) finite-memory Markov model, called the D-Markov machine, where a Bayesian nonparametric structure is adopted for: (i) automated selection of parameters in D-Markov machines, and (ii) online sequential testing to provide dynamic data-driven and coherent statistical analyses of combustion instability phenomena without solely relying on computationally intensive (physics-based) models of combustion dynamics. The proposed method has been validated on an ensemble of pressure time series from a laboratory-scale combustion apparatus. The results of instability prediction have been compared with those of other existing techniques.
TOPICS: Modeling, Time series, Combustion, Machinery, Dynamics (Mechanics), Pressure, Algorithms, Gas turbines, Sensors, Pressure measurement, Chemiluminescence, Combustion chambers, Physics, Testing, Statistical analysis
Technical Brief  
Chuanfeng Wang
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037284
Curve tracking control is challenging and fundamental in many robotic applications for an autonomous agent to follow a desired path. In this paper, we consider a particle, representing a fully-actuated autonomous robot, moving at unit speed under steering control in the three-dimensional (3D) space. We develop a feedback control law that enables the particle to track any smooth curve in the 3D space. Representing the 3D curve in the natural Frenet frame, we construct the control law under which the moving direction of the particle will be aligned with the tangent direction of the desired curve and the distance between the particle and the desired curve will converge to zero. We demonstrate the effectiveness of the proposed 3D curve tracking control law in simulations.
TOPICS: Particulate matter, Tracking control, Robots, Simulation, Engineering simulation, Robotics, Feedback
Noah Manring, Laheeb Muhi, Roger Fales, Viral S. Mehta, Jeff Kuehn and Jeremy Peterson
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037285
In this paper, a simple feedback linearization method is used to improve the tracking performance of a linear hydraulic-actuator. This research uses an open-centered 4-way valve to control the displacement of the hydraulic actuator, based upon an input command from the operator. In this research, the operator is modeled as a first-order system with a bandwidth frequency of 2 Hz. The feedback linearization method is used to adjust the operator input based on the measurement of fluid pressure on only one side of the actuator, and the pump pressure that supplies the valve. No other sensing is needed. Using this approach, the R-squared value for tracking a sinusoidal displacement of the actuator, and the bandwidth frequency of the actuator, are increased. Furthermore, it is shown that the feedback linearization method reduces and nearly eliminates the load dependence of the tracking response, which means that operators should have less difficulty learning how to operate the machine over a wide range of conditions, and the overall productivity of the machine should go up. In summary, the elegance of this model is found in the fact that it is very simple to implement and that the alterations in output performance are greatly enhanced.
TOPICS: Actuators, Feedback, Valves, Displacement, Pressure, Machinery, Stress, Fluid measurement, Pumps
Xuefeng Wang and Weidong Zhu
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037283
The kinematic model of an infinitely variable transmission (IVT) is introduced, and the nonlinear differential equation for the dynamic model of the IVT system with a permanent magnetic DC motor and a magnetic brake is derived. To make the average of the input speed converge to a desired constant for any input power and output load, an integral time-delay feedback combined with an open loop control is used to adjust the speed ratio of the IVT. The speed ratio for the open loop control is obtained by a modified incremental harmonic balance method. Existence and convergence of the periodic solution are proved under a condition for parameters of the IVT system, and uniqueness of the periodic solution is proved by converting the nonlinear differential equation to a new differential equation that is Lipchitz in the dependent variable and piecewise continuous in the independent variable. A time-delay variable that is an approximation of the average of the input speed is used as the feedback to control the changing rate of the speed ratio. The IVT system with the time-delay control variable can be converted to a distributed-parameter system. Thus, the Tau spectral method is used to design the time-delay feedback control so that the IVT system is locally exponentially stable. The static error from the open loop control is eliminated; the feedback control variable with time delay is smoother than that without time delay, which yields a lower control effort and more robust control design, where the time-delay variable that acts as a low-pass filter reduces the effect of the instantaneous change of the IVT system.
TOPICS: Stability, Design, Delays, Feedback, Nonlinear differential equations, Dynamic models, Brakes, Kinematics, Low-pass filters, Errors, Differential equations, Robust control, Approximation, Engines, Motors, Stress
Qinghua Meng, Chunjiang Qian and Pan Wang
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037266
The paper presents a lateral motion stability control method for an electric vehicle driven by four in-wheel motors subject to time-variable high speeds and uncertain disturbances caused by severe road conditions, siding wind forces and different tire pressures. In order to tackle the uncertain disturbances, an almost disturbance decoupling method (ADD) using sampled-data output feedback control which is more suitable for computer implementation is proposed based on the domination approach. The proposed controller can attenuate the disturbances' effect on the output to an arbitrary degree of accuracy. Simulation results under different speeds by MATLAB show the effectiveness of the control method.
TOPICS: Stability, Motors, Electric vehicles, Feedback, Wheels, Wind, Matlab, Roads, Simulation results, Tires, Computers, Control equipment
Mohammad Saleh Tavazoei and Hamed Taghavian
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037268
BIBO stability of distributed-order LTI systems with uncertain order weight functions and uncertain dynamic matrices is investigated in this paper. The order weight function in these uncertain systems is assumed to be totally unknown lying between two known positive bounds. First, some properties of stability boundaries of fractional distributed-order systems with respect to location of eigenvalues of dynamic matrix are proved. Then, on the basis of these properties it is shown that the stability boundary of distributed-order systems with the aforementioned uncertain order weight functions is located in a certain region on the complex plane defined by the upper and lower bounds of the order weight function. Thereby, sufficient conditions are obtained to ensure robust stability in distributed-order LTI systems with uncertain order weight functions and uncertain dynamic matrices. Numerical examples are presented to verify the obtained results.
TOPICS: Weight (Mass), Stability, Uncertain systems, Eigenvalues
Majid Moradi Zirkohi
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037269
In this paper, a simple model-free controller for electrically driven robot manipulators is presented using function approximation techniques (FAT) such as Legendre polynomials (LP) and Foureier series (FS). According to the orthogonal functions theorem, LP and FS can approximate nonlinear functions with an arbitrary small approximation error. From this point of view, they are similar to fuzzy systems and can be used as controller to approximate the ideal control law. In comparison with fuzzy systems and neural networks, LP and FS are simpler and less computational. Moreover, there are very few tuning parameters in LP and FS. Consequently, the proposed controller is less computational in comparison with fuzzy and neural controllers. The case study is an articulated robot manipulator driven by permanent magnet DC motors. Simulation results verify the effectiveness of the proposed control approach and its superiority over neuro-fuzzy controllers.
TOPICS: Manipulators, Control equipment, Fuzzy logic, Permanent magnets, Approximation, Artificial neural networks, Errors, Function approximation, Motors, Polynomials, Simulation results, Theorems (Mathematics)
Richard Meyer, Scott Johnson, Ray A. DeCarlo, Steve Pekarek and Scott Sudhoff
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037270
This paper investigates the supervisory-level, fault tolerant control of a 2004 Prius powertrain. The fault considered is an inter-turn short circuit (ITSC) fault in the traction drive (a surface mount permanent magnet synchronous machine (SPMSM) for which its rotor is part of the vehicle's driveline). ITSC faults are caused by electrical insulation failures in the stator windings where part of a phase winding remains functional while the remaining decoupled windings form a self contained loop. Because the permanent magnets on the rotor (driveline) shaft are able to induce very large eddy currents in this self contained loop if its rotational velocity is left unchecked, the maximum allowable driveline speed, and consequently vehicle speed, must be reduced to avoid exceeding the drive's operational thermal limits during a fault. A method for detecting these ITSC faults and the induced eddy current in a SPMSM using a moving horizon observer (MHO) is reviewed. These parameters then determine which previously computed, fault level dependent SPMSM input-output power efficiency map and maximum safe operating speed is utilized by the supervisory-level controller. The fault tolerant control is demonstrated by simulating a Prius over a 40~s drive velocity profile with fault levels of 0.5\%, 1\%, 2\%, and 5\% detected at the midpoint of the profile. For comparison, the Prius is also simulated without a traction motor fault. Results show that the control reduces vehicle velocity upon detection of a fault to an appropriate safe value.
TOPICS: Machinery, Control equipment, Eddies (Fluid dynamics), Engines, Motors, Permanent magnets, Energy efficiency, Rotors, Vehicles, Circuits, Failure, Hybrid electric vehicles, Insulation, Stators, Traction, Winding (process), Surface mount packaging
Cong Wang, Minghui Zheng, Zining Wang, Cheng Peng and Masayoshi Tomizuka
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037265
Vibration suppression is of fundamental importance to the performance of industrial robot manipulators. Cost constraints, however, limit the design options of servo and sensing systems. The resulting low drive-train stiffness and lack of direct load side measurement make it difficult to reduce the vibration of the robot's end-effector and hinder the application of robot manipulators to many demanding industrial applications. This paper proposes a few ideas of iterative learning control (ILC) for vibration suppression of industrial robot manipulators. Compared to the state-of-the-art techniques such as the dual-stage ILC method and the two-part Gaussian Process Regression method, the proposed method adopts a two-degree-of-freedom structure and gives a very lean formulation as well as improved effects. Moreover, in regards to the system variations brought by the nonlinear dynamics of robot manipulators, two robust formulations are developed and analyzed. The proposed methods are explained using simulation studies and validated using an actual industrial robot manipulator.
TOPICS: Vibration suppression, Manipulators, Iterative learning control, Nonlinear dynamics, Stiffness, Trains, End effectors, Servomechanisms, Simulation, Stress, Design, Vibration
Xinyi Ge, Jeffrey L. Stein and Tulga Ersal
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037271
This paper focuses on Norm-Optimal Iterative Learning Control (NO-ILC) for Single-Input-Single-Output (SISO) Linear Time Invariant (LTI) systems and presents an infinite time horizon approach for a frequency-dependent design of NO-ILC weighting filters. Because NO-ILC is a model based learning algorithm, model uncertainty can degrade its performance; hence, ensuring Robust Monotonic Convergence (RMC) against model uncertainty is important. This robustness, however, must be balanced against convergence speed and steady state error. The weighting filter design approaches for NO-ILC in the literature provide a limited design freedom to adjust this trade-off. Moreover, even though qualitative guidelines to adjust the trade-off exist, a quantitative characterization of the trade-off is not yet available. To address these two gaps, a frequency-dependent weighting filter design is proposed in this paper and the robustness, convergence speed and steady state error are analyzed in the frequency domain. An analytical expression characterizing the fundamental trade-off of NO-ILC with respect to robustness, convergence speed and steady state error at each frequency is presented. Compared to the state of the art, a frequency-dependent filter design gives increased freedom to adjust the trade-off between robustness, convergence speed, and steady state error, because it allows the design to meet different performance requirements at different frequencies. Simulation examples are given to confirm the analysis and demonstrate the utility of the developed filter design technique.
TOPICS: Design, Errors, Filters, Robustness, Steady state, Iterative learning control, Tradeoffs, Uncertainty, Engineering design processes, Simulation, Algorithms
Design Innovation Paper  
Mingwei Sun, Zhiqiang Gao, Zenghui Wang, Yuan Zhang and Zengqiang Chen
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037267
This paper demonstrates that the Coulomb friction, the most difficult part of friction to be compensated because of its discontinuity with respect to the velocity, can be precisely compensated without either its mathematical model or a velocity measurement, as commonly required in the literature. Instead, the necessary information needed in the friction compensation is obtained in real time from an extended state observer in the context of a common proportional-derivative motion control system, using the proposed linear reference compensation scheme. The robustness of the observer design to the time-delay uncertainty resulting from model reduction is thoroughly investigated, which illustrates the extent to which a high bandwidth can be employed to achieve favorable dynamic performance. Finally, numerical examples are provided to validate the proposed method.
TOPICS: Friction, Coulombs, Velocity measurement, Uncertainty, Motion control, Design, Delays, Robustness, State estimation
Neng Wan, Weiran Yao and Mingming Shi
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037211
External perturbations and actuator faults are two practical and significant issues that deserve designers' considerations when synthesizing the controllers for spacecraft rendezvous. With these constraints, a composite robust fault-tolerant control scheme, which consists of an integral sliding mode (ISM) auxiliary controller and a guaranteed cost fault-tolerant controller, is proposed in this paper for thrust-limited rendezvous in near-circular orbits. External disturbances are attenuated by a reliable ISM auxiliary controller; while an improved guaranteed cost fault-tolerant controller is adopted to stabilize the nominal rendezvous system with actuator faults. Comparisons with previous works as well as a more practical and challenging simulation example are presented to verify the advantages of our composite control scheme.
TOPICS: Composite materials, Thrust, Space vehicles, Control equipment, Actuators, Simulation
Ido Halperin, Grigory Agranovich and Yuri Ribakov
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037168
Semi-active systems provide an attractive solution for the structural vibration problem. A useful approach, aimed to simplify the control design, is to divide the control system into two parts: an actuator and a controller. The actuator generates a force that tracks a command which is generated by the controller. Such approach reduces the complexity of the control law design as it allows for complex properties of the actuator to be considered separately. In this study, the semi-active control design problem is treated in the framework of optimal control theory by using bilinear representation, a quadratic performance index and a constraint on the sign of the control signal. The optimal control signal is derived in a feedback form by using Krotov's method. To this end, a novel sequence of Krotov functions which suits the multi-input constrained bilinear-quadratic regulator problem is formulated by means of quadratic form and differential Lyapunov equations. An algorithm is proposed for the optimal control computation. A proof outline for the algorithm convergence is provided. The effectiveness of the suggested method is demonstrated by numerical example. The proposed method is recommended for optimal semi-active feedback design of vibrating plants with multiple semi-active actuators.
TOPICS: Control systems, Control equipment, Actuators, Algorithms, Design, Optimal control, Vibration, Computation, Feedback, Signals
Milad Jalali, Amir Khajepour, Shih-ken Chen and Bakhtiar B. Litkouhi
J. Dyn. Sys., Meas., Control   doi: 10.1115/1.4037166
In this paper, a new approach is proposed to deal with the delay in vehicle stability control using model predictive control (MPC). The vehicle considered here is a rear-wheel drive electric (RWD) vehicle. The yaw rate response of the vehicle is modified by means of torque vectoring so that it tracks the desired yaw rate. Presence of delay in a control loop can severely degrade controller performance and even cause instability. The common approaches for handling delay are often complex in design and tuning or require an increase in the dimensions of the controller. The proposed method is easy to implement and does not entail complex design or tuning process. Moreover, it does not increase the complexity of the controller, therefore the amount of online computations is not appreciably affected. The effectiveness of the proposed method is verified by means of CarSim/Simulink simulations as well as experiments with a rear-wheel drive electric SUV. The simulation results show that the proposed method can significantly reduce the adverse effect of the delay in the control loop. Experimental tests with the same vehicle also confirm the effectiveness of this technique. Although this method is applied to a vehicle stability control, it is not specific to a certain class of problems and can be easily applied to a wide range of model predictive control problems with known delays.
TOPICS: Delays, Electric vehicles, Yaw, Vehicles, Control equipment, Stability, Design, Wheels, Predictive control, Simulation results, Engineering simulation, Computation, Torque, Dimensions, Simulation

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