Initial Value Compensation Research Articles

An Initial Value Problem for State of Charge Estimation of Lithium‐Ion Batteries with an Adaptive Fractional‐Order Unscented Particle Filter

AbstractThis paper proposes an adaptive fractional‐order unscented particle filter (AFOUPF) with the initial value compensation (IVC) to enhance the estimation accuracy of the state of charge (SOC) for lithium‐ion batteries (LIBs). First, to correctly reflect the dynamic properties of LIBs, a fractional‐order system (FOS) with a constant phase component is constructed. Second, to discretize the FOS equation of LIBs, the Grünwald–Letnikov difference, Caputo derivative and Rieman–Liouville difference are employed to establish the corresponding difference equation. Third, a map function is applied to keep the order and SOC of the FOS within an appropriate interval. Further, an approach of IVC is provided for the AFOUPF to increase the accuracy of SOC estimation, taking into account that the accuracy of SOC estimation is impacted if the order of the FOS is relatively small in (0, 1). By utilizing the augmented vector approach, the simultaneous estimations of order, parameters, initial value, and SOC are resolved. Besides, an iterative approach that accommodates the noise covariance matrices is proposed to improve the estimation accuracy. The AFOUPF conducts an unscented transform and resampling on each particle, resulting in a high SOC estimation accuracy in complicated situations. Finally, the availability of AFOUPF is tested by several experiments.

Initial value compensation of an adaptive fractional-order unscented Kalman filter for estimating the state of charge of lithium-ion batteries

This study indicates an adaptive fractional-order unscented Kalman filter (UKF) with unknown parameters and order, which provides a higher accuracy of SOC estimation. In order to solve the problem of reduced estimation accuracy caused by the low order in the adaptive estimation, this paper adopts the augmented vector method for the initial value compensation (IVC) to reduce the impact of initial values on the estimation accuracy. Because the parameters of the LIB change with the charge and discharge of the battery use and the working conditions, and to increase the ability of the adaptive SOC estimation, this paper studies an adaptive unscented Kalman filter (AUKF) algorithm for the joint estimation of state, parameters, and order of model based on IVC. The algorithm can achieve the adaptive estimation of SOC under different working conditions. Finally, several sets of experiments are conducted under different working conditions to verify that the AUKF algorithm with IVC can achieve the effective estimation of SOC, and the adaptive effect and the estimation error of IVC on the algorithm are better than those without IVC.

State of charge estimation for lithium-ion batteries based on an adaptive fractional-order cubature Kalman filter with initial value compensation

An adaptive fractional-order cubature Kalman filter with the initial value compensation is proposed for the state of charge (SOC) estimation of a lithium-ion battery. Firstly, we build a fractional-order battery model and discretize the state equation using Grünwald–Letnikov difference. Secondly, the initial values of the states are considered as the augmented states to be estimated to weaken the influence of the initial values to the estimation effect of the SOC, and the augmented state equation containing the SOC, parameters and orders of the model and the initial values of the states is established via the augmented vector method. Then, a linear Kalman filter for the estimation of the coefficients in the measurement equation and a cubature Kalman filter for the real-time estimation of the SOC, model parameters and orders are designed. Finally, we give the formulas to estimate the noise covariance matrices by an iterative method, and test the performance of the proposed algorithm by several sets of experiments.

Negative quadrant glitch suppression control of ball‐screw‐driven stage for machine tool by friction compensation and initial value compensation

AbstractBall‐screw‐driven stages are widely used as feed systems of industrial equipment such as machine tools. Rolling friction in the stages causes a large tracking error called a quadrant glitch at a velocity reversal. Although the model‐based friction compensation reduces the quadrant glitch, it often leads to a tracking error in the direction opposite to the quadrant glitch. This study aims to present a control system that reduces both the quadrant glitch and opposite‐direction error. This is achieved by combining the model‐based friction compensation and initial value compensation. The effectiveness of the proposed control system is verified by simulations and experiments with two‐axis experimental setup.

Negative Quadrant Glitch Suppression Control of Ball-screw-driven Stage for Machine Tool by Friction Compensation and Initial Value Compensation

Negative Quadrant Glitch Suppression Control of Ball-screw-driven Stage for Machine Tool by Friction Compensation and Initial Value Compensation

Full adaptive Kalman filters for nonlinear fractional-order systems containing unknown parameters and fractional-orders

In this study, full adaptive Kalman filters are designed for continuous-time nonlinear fractional-order systems (FOSs) containing unknown parameters and fractional-orders. First, the estimated FOS is discretized using the Grünwald–Letnikov difference method to transform the fractional-order differential equation into a difference equation. Then, in terms of the nonlinear function contained in the investigated system, the Taylor expansion formula is adopted to linearize the discretized equation. Based on the method of augmented vector, an augmented state equation is established by state equations, unknown parameter equations, and fractional-order equation to achieve the state estimation. Besides, the sigmoid function is brought to ensure that the estimation of the fractional-order is performed in a suitable range. Because the covariance matrices of noises are difficult to be measured in physical systems, we also concern the problems on the state estimation, parameter estimation, and fractional-order estimation under the cases that the covariance matrix of process noise is unknown or the covariance matrix of measurement noise is unknown. Considering that the initial value can produce an error of state estimation and parameter identification for the FOS defined under the Caputo sense, the augmented vector method is used to achieve the initial value compensation. Finally, the effectiveness of the proposed algorithms is validated by four examples.

Initial-value compensation of a proportional–integral–derivative controller for non-overshooting motion

This article presents a proportional–integral–derivative controller design for monotonic, non-overshooting output responses of a class of second-order plants that do not need to be initially at res...

A rate-based robust queue management system through multi-loop internal model controller with initial value compensation

An efficient congestion control approach should gain weighted fairness and also robustness against external disturbances. Moreover, variations in the number of active sources cause a network to operate as a switched system in which the initial values affect the transient response. The main contribution of this article is to design a rate-based adaptive robust queue management contemplating the initial value compensation (IVC). The congestion is avoided via Two-Degree-of-Freedom Internal Model Control protocol as a robust procedure. The utilisation factors are designated according to the delay of each source (weighted fairness) in which the sources will use the maximum value of the bottleneck capacity (maximum utilisation). On the other hand, the number of the users is determined adaptively and effects of non-zero initial values are eliminated through a protocol called IVC. Simulation results through Network Simulator 2 and Simulink software confirm the analytical results and the efficacy of the proposed method.

Mode Switching Feedback Compensation Considering Rolling Friction Characteristics for Fast and Precise Positioning

This paper presents a mode switching feedback (FB) compensation methodology based on rolling friction models for the fast and precise positioning of table drive systems. Rolling friction in the table drive mechanisms behaves as a nonlinear elastic component in the micro displacement region and deteriorates the position settling performance with slow responses. Effects of the rolling friction on the positioning, therefore, should be compensated to provide the desired control performance. The authors have already proposed a rolling friction model-based friction compensation scheme to improve the slow settling responses. The conventional approach, however, could not suppress vibratory settling responses due to unknown model errors and/or plant perturbations, and there still remains the performance deterioration in the positioning accuracy to be solved. In this research, therefore, a novel mode switching FB compensation considering the rolling friction properties is applied to provide the desired settling performance with well-suppression of both vibratory response and slow response. The feature of the proposed approach is that the vibratory and slow responses at the settling are handled as an initial value response of the FB control system in the micro displacement region and can be suppressed in a mode switching control manner on the basis of initial value compensation frameworks utilizing the elastic characteristic of the rolling friction. The proposed approach has been verified by numerical simulations and experiments using a prototype of industrial table positioning devices.

Initial Friction Compensation Using Rheology-Based Rolling Friction Model in Fast and Precise Positioning

This paper presents an initial friction compensation by a disturbance observer which is designed on the basis of a rolling friction model (RFM) for the fast and precise positioning of ball-screw-driven table systems. Rolling friction in the table drive mechanism behaves as a nonlinear elastic component in the microdisplacement region, deteriorating the fine settling performance. The effects of the rolling friction on the positioning, therefore, should be compensated to provide the desired control performance. In the compensator design, a feedback control with a disturbance observer allows the plant system to behave as a nominal one with a robust stability and compensates for the effects of nonlinear friction on the positioning performance. The disturbance observer, however, inherently includes an estimation delay at the starting motion due to low-pass filters and delay components. In this paper, therefore, an RFM is adopted as an initial value compensation of the disturbance observer to compensate for the initial friction behavior, providing the delay-free estimation. The proposed compensation method has been verified by numerical simulations and experiments using a prototype for industrial positioning devices.

Improvement of Settling Performance by Mode-Switching Control With Split Initial-Value Compensation Based on Input Shaper

This paper presents a novel initial-value-compensation (IVC) technique for mode-switching-control approaches in the fast and precise positioning of mechatronic systems. Parameter perturbations in plant mechanism and/or actuator generally deteriorate the positioning performance. In order to realize the desired positioning performance with robust property against the perturbations, the mode-switching control with the IVC is one of the promising approaches, where the timing of the mode switching and the time interval of the IVC critically affect the compensation performance. However, the shortening in the IVC operation interval causes an increase in the input amplitude, which leads to deterioration of the positioning performance due to saturation in control input. In this paper, therefore, a split IVC based on input-shaping techniques is applied to prevent the input amplitude from being saturated and to provide adaptiveness and robustness against unknown parameter perturbations. The effectiveness of the proposed approach has been verified by experiments using a prototype of galvanoscanners.

Initial value compensation with additional input considering optimization of control input

AbstractThis paper presents a novel method of initial value compensation (IVC) with additional input by considering the optimization of control input. IVC has been used to improve the control performance of various control systems with different initial values. Essential subjects, however, have still remained: in the conventional IVC approaches, the increases in the amplitude and number of high‐frequency components of the control input that accompany an increase in the control bandwidth could not be avoided. In this research, therefore, an optimization approach for control input is applied under the constraints of the conventional IVC approach. The effectiveness of the proposed approach has been verified by numerical simulations and experiments using a prototype. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(2): 63‐73, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21026

パーソナルモビリティロボットの走行切換制御

The present paper introduces a novel standing-up control strategy based on Initial Value Compensation (IVC) for a Personal Mobility Robot (PMR). PMRs, which are wheeled-inverted-pendulum-type mobility-assist devices, offer the following advantages: (1) they can turn at a point; (2) they can maintain a level seating posture on a slope; and (3) they have a smaller footprint than conventional electric wheelchairs with four wheels. On the other hand, the user must maintain the posture of the PMR by using additional assist wheels on the ground when mounting/dismounting the PMR and working while seated on the PMR. In order to satisfy these requirements, we propose the following approach. First, the PMR accelerates to lift its assist wheels off the ground and determines whether the assist wheels are in contact with the ground. The feedback controller is then switched to wheeled-inverted-pendulum mode using the proposed IVC. The proposed IVC is designed such that the transient responses are improved and the amplitude of the control input and the jerk component are suppressed, in order to reduce the shock felt by the driver. The effectiveness of the proposed approach has been verified by conducting numerical simulations and experiments using a prototype PMR.

134 セミアクティブニーボルスターを用いた乗員下肢保護制御系設計

This paper presents control system design for occupant lower extremity protection in the event of a frontal car crash. A semi-active knee bolster is used to protect occupant lower extremities. The semi-active knee bolster varies the damping coefficient of the knee bolster. The control system design of the semi-active knee bolster is based on a design method of an active knee bolster. LQI (Linear Quadratic Integration) control with an initial value compensation input is applied. We obtain an optimal reference signal of the contact force between the knees and the instrument panel by considering characteristics of the semi-active actuator and the closed loop control system. The control system of the semi-active knee bolster follows the reference signal of the contact force. The protective control system with the semi-active knee bolster is effective for reducing the femur load, verified by carrying out simulations.

Real‐time compensation for positioning performance using on‐line parameter identification and initial value compensation

AbstractVariations and/or uncertainties in environments of mechatronic systems, such as electrical/mechanical parameter changes and nonlinear components, generally deteriorate the motion control performance. In our research, the fast and precise position settling performance for parameter variations in positioning devices can be improved by techniques of an on‐line parameter identification and an initial value compensation. The proposed technique allows the positioning systems to be adaptive and robust for unknown parameter variations. The effectiveness of the approach has been verified by numerical simulations and experiments using a prototype. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(2): 40–49, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20926

2P1-C10 パーソナルモビリティロボットの初期値補償に基づく走行切換制御

The present paper introduces a novel standing-up control strategy using Initial Value Compensation (IVC) for a Personal Mobility Robot (PMR). Personal mobility robots, which are wheeled inverted pendulum type mobility-assist devices, have the advantages of a small turn radius, maintaining a level seating posture on a slope, and a small footprint as compared to conventional electric wheelchairs with four wheels. On the other hand, the user must maintain the posture of the PMR by the use of additional assist wheels on the ground when mounting/dismounting and working from the PMR. In order to achieve these requirements, we propose the following approach. First, the PMR accelerates to lift its assist wheels off the ground and detects whether the assist wheels are in contact with the ground. The feedback controller is then switched to wheeled inverted pendulum mode using the proposed IVC. The proposed IVC is designed to improve the transient responses and suppress the amplitude of the control input and the jerk component for reducing the shock to the driver. The effectiveness of the proposed approach has been verified by numerical simulations and experiments using a prototype PMR.

転がり摩擦特性を考慮した有限ステップ整定初期値補償による位置決め整定時の遅い応答抑制

転がり摩擦特性を考慮した有限ステップ整定初期値補償による位置決め整定時の遅い応答抑制

A Linear Matrix Inequality Approach to Initial Value Compensation for Mode Switching Control in Hard Disk Drive Servo Systems

In switching from the track-seeking or track-jumping control mode to the track-following control mode in hard disk drives, initial values of the feedback controller are tuned such that the transient response is improved. We present a simple initial value compensation (IVC) method using linear matrix inequalities (LMIs) instead of the conventional method that uses a Lyapunov equation. The LMIs include conditions for improving the transient response performance in the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -norm sense and minimizing the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">infin</sub> norm of the closed-loop system in order to reduce the controlled outputs such as plant states, tracking error, and control efforts. We obtain optimal initial values of the controller by solving an optimization problem with constraints represented by only one LMI. We verified the feasibility of the method by using a series of simulations.

Controller‐Switching Strategy for HDD Servo Systems with Measurement Errors and Constraints on State and Control Variables

AbstractThe head‐positioning control system of a hard disk drive (HDD) must enable precise positioning and high‐speed access. Mode switching control (MSC) has widely been used to meet these control requirements. One of the issues with MSC is how to determine the controller‐switching strategy, which needs decisions on the controller's switching conditions and its initialization. We propose a method that utilizes initial value compensation (IVC) to determine the initial state of the controller. Although mode switching is non‐linear, transient responses can be improved if the control system takes the initial state response after mode switching into consideration. IVC, which is based on this, can improve the transient response after mode switching. We also propose a method, which is based on the concept of a maximal output admissible set, of determining the switching conditions. It takes pointwise‐in‐time constraints and measurement errors in the plant's initial state into consideration. Experimental evaluations of the switching‐control strategy we propose were undertaken with a 2.5‐inch form‐factor HDD. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley &amp; Sons, Inc.

Initial Value Compensation Using Additional Input for Semi-Closed Control Systems

This paper presents a novel initial value compensation (IVC) using an additional input for semi-closed control systems. The authors have already proposed the IVC approach using the additional input for residual vibration suppression in the fast and precise positioning control. In the approach, however, an essential subject has remained, i.e., the positioning control in the load side could not satisfy the required performance because the systems have been constructed under the assumption of a semi-closed control system. An improvement of the control performance in load position, therefore, is discussed in this paper, where the appropriate assignments of poles and zeros in IVC are ensured, considering the transfer functions of position in both sensor and load for the control initial values. The effectiveness of the proposed approach has been verified by numerical simulations and experiments using a prototype.