Transactions of the Institute of Measurement and Control

Singh, Jay P; Roy, Binoy K

doi: 10.1177/0142331217727580pmid: N/A

The objectives of the paper are (i) to develop a new 4-D conservative chaotic system with hidden chaotic orbits, (ii) to design a second order adaptive time varying sliding mode control for the synchronization between two identical proposed chaotic systems in the presence of matched disturbances and (iii) to compare the performances of the proposed controller with two available controllers which have been published recently. The chaotic nature of the proposed system is validated using theoretical and numerical tools like divergence property, Lyapunov exponents, Lyapunov spectrum, bifurcation diagram, phase portrait, Poincaré map and a frequency spectrum. The new conservative chaotic system exhibits the coexistence of hidden chaotic orbits with no equilibrium point. The new system is synchronized with itself using the proposed second-order adaptive time varying sliding mode control technique in the presence of matched disturbances and by considering different initial conditions. During synchronization, the parameters of both the systems, gains of the first order and second order sliding surfaces and the gains of the switching laws are considered as unknown and estimated adaptively. Only two control inputs are used to synchronize all the four states of the system. The effectiveness of the proposed controller is compared with two available controllers for the synchronization of chaotic systems and it is found that the proposed controller performs much better than the two available controllers.

Zhao, Wanzhong; Ji, Lin; Wang, Chunyan

doi: 10.1177/0142331217727581pmid: N/A

The mainstream rollover evaluation index, lateral load transfer rate (LTR), is commonly used in the rollover control field. However, it is not instant enough to reflect the rollover tendency since it can only reflect the load transfer rate of one side wheels while single rear wheel leaves the ground first during rollover happens. In order to monitor the rollover tendency more instantly and improve the reliability of anti-rollover control system, a new evaluation index called predictive vertical tire force (PVTF) is proposed, which is based on the single vertical tire force and merges both iterative prediction and derivative prediction methods. Meanwhile, an optimization is taken to solve the contradiction between prediction time and deviation. Secondly, using the PVTF as the measurement output, an anti-rollover control system based on active steering is established in this paper. In order to achieve the desired tracking effect and anti-jamming capability, a two-way H∞ controller is adopted in the anti-rollover control system. Lastly, the simulation results of J-turn condition and NHTSA (national highway traffic safety administration) condition are conducted and the results indicate that the anti-rollover control system has strong stability and robustness. Meanwhile, benefit from the pre-warning function of PVTF, the controller is triggered earlier and the vertical tire forces of four wheels are controlled to be positive all the time, which is beneficial for handling stability.

Zhang, Dandan; Duan, Guangren

doi: 10.1177/0142331217734040pmid: N/A

In this paper, the rotating consensus tracking problem for second-order multi-agent systems with external disturbances in three-dimensional space is considered. It is assumed that only a subset of the agents is given direct access to the desired trajectory information. Based on a backstepping control technique, a distributed adaptive rotating consensus protocol, driving all followers to track the leader, is developed for the case when both the relative position and relative velocity measurements are available for feedback. Moreover, the proposed control protocol design method is also extended to the case that the relative velocities are not measured. Through Lyapunov stability analysis, it is shown that, under the proposed control protocols, all followers can track the leader rotating around a common point with and without relative velocity measurements. Simulation results are included to demonstrate the effectiveness of our schemes.

Wang, Fengchen; Wang, Decheng; Sun, Jia; Zhao, Jianzhu

doi: 10.1177/0142331217728567pmid: N/A

This paper proposes a novel intelligent optimal control strategy for crawler vehicles with semi-active suspension. The proposed control strategy aims at improving vehicle ride comfort by addressing contradictory suspension properties requirements of ride comfort and handling stability simultaneously. After establishing seven degrees of freedom dynamic model of the crawler vehicle, a comprehensive evaluation index is developed to trade off among various vehicle performances, which include ride comfort, damper thermal reliability, elastic element fatigue and handling stability. Then, using modified staged continuous tabu search (MSCTS) algorithm, the optimal control efforts of semi-active suspension, damping ratios, are determined by minimizing the cost function defined by the comprehensive evaluation index. Demonstrated by simulations with triangle convex block and random ground roughness excitations, MSCTS control strategy can successfully improve ride comfort performance and achieve the optimal comprehensive performance as well.

Chen, Shiyu; Yuan, Jianping; Wang, Zheng; Zhu, Zhanxia

doi: 10.1177/0142331217728570pmid: N/A

This paper aims to address the attitude stabilization issue of post-capture combination with underactuated actuators, measurement inaccuracy and unknown external disturbances during on-orbit servicing. A precise and practical form of underactuated attitude dynamics is proposed for the asymmetric combination with two control torques. With the adopted partial stabilization strategy, a sliding mode controller is first proposed to achieve partial stabilization of the combination against the effect of unknown external disturbances. Through the additional consideration of the measurement inaccuracy in the inertia tensor and the mass centroid, an underactuated adaptive sliding mode controller with compensation laws is proposed in presence of uncertainties and disturbances. Numerical simulations validate the effectiveness of proposed partial attitude stabilization controllers.

Mondal, Ujjwal; Sengupta, Anindita; Dey, Naiwrita

doi: 10.1177/0142331217729202pmid: N/A

This paper is concerned with the development of a Modified Finite Dimensional Repetitive Control (MFDRC) system. Conventional FDRC is modified through parameterization of the controller using co-prime factorization. The proposed method of controller design specifies the input output characteristics beforehand, ensuring highly accurate tracking and disturbance rejection property of the system subjected to periodic reference input. Another problem is the stabilization issues in the input–output and the disturbance rejection characteristics of a conventional repetitive control system with respect to the periodic reference input owing to have infinite number of poles in the transfer function of it. It is desirable that the transfer functions from both the reference input and the disturbance to the output have a finite number of poles and that will be taken care of in the proposed scheme of MFDRC design depicted in this paper. The performance of designed controller has been validated in steps applied to a laboratory based servo system. Comparisons are done using conventional PID controller, FDRC-based PID controller and MFDRC to show advantage, disadvantage or limitation of applied control scheme.

Bettayeb, Maamar; Al–Saggaf, Ubaid Muhsen; Djennoune, Said

doi: 10.1177/0142331217729425pmid: N/A

This paper deals with the design of a fractional-order chaotic secure communication scheme. On the emitter side, a fractional-order Chua’s system is used as the drive system to generate the encrypted message signal. The input secret message is modulated in the chaotic dynamics by inclusion rather than being directly added to the chaotic signal on the transmission line. A single channel is used for transmission of the encrypted signal. At the receiver side, a step-by-step sliding mode fractional-order chaotic observer subject to unknown input is proposed as the response system to obtain robust synchronization between the emitter and the receiver. After chaos synchronization is achieved at the receiver side, an estimation of the state variables is obtained and the plaintext is recovered. Finite-time convergence of both state and unknown input estimation errors is established. The efficiency of this proposed secure communication scheme is illustrated by numerical simulations.

Liu, Zengjun; Wang, Lei; Wang, Wei; Song, Tianxiao

doi: 10.1177/0142331217729203pmid: N/A

Rotating modulation technique is a mature method that has been widely used in the rotational inertial navigation system (RINS). Tri-axis RINS has three gimbals, and the Inertial Measurement Unit can rotate along three directions to modulate the inertial devices’ errors, so that the navigation accuracy of the system can be greatly improved. However, the outputs of attitudes are easily affected by the non-orthogonal angles of gimbals, which should be accurately calibrated and compensated. In this paper, the effects of the non-orthogonal angles on the attitudes are discussed detailed and simulations based on Matlab are conducted to verify that firstly; then, a self-calibration method based on the outputs of the fiber optic gyroscope and photoelectric encoder is proposed. Experimental results in a real tri-axis RINS show that the attitude outputs accuracy are improved from 150” to less than 10”, which verify the practicability of the calibration method proposed in this paper.

Zhu, Rusong; Yin, Guofu; Tang, Gengsheng; Wang, Hai; Zhang, Shuangxi

doi: 10.1177/0142331217728569pmid: N/A

Temperature control in a cryogenic wind tunnel is the key to realizing finely controlled Reynolds number close to true flight. This study deploys the L1 adaptive control methodology to ensure the total temperature profile of the cryogenic wind tunnel tracks a specified reference trajectory. After introducing a non-linear model of a cryogenic wind tunnel and a linear temperature model, a linear–quadratic–Gaussian (LQG) controller is implemented as the baseline controller. The L1 adaptive controller with piecewise constant adaptive law is used as an augmentation to the baseline controller to cancel the matched and unmatched uncertainties within the actuator’s bandwidth. By introducing two modifications to the standard L1 adaptive controller, which are the transportation delay modelling in the state predictor and the non-linear state dependent filter, the L1 adaptive controller improves the performance of the baseline controller in the presence of uncertainties in temperature control, guaranteeing proper stability and delay margin. The simulation results and analysis demonstrate the effectiveness of the proposed control architecture. The main contribution of this paper lies in the first applications of L1 adaptive control to the wind tunnel control problem and the non-linear state dependent filter in L1 adaptive control structure.

Wei, Wei; Cheng, Han-miao; Li, Fan; Tang, Deng-ping; Xia, Shui-bin

doi: 10.1177/0142331217729747pmid: N/A

When sampling analog signal, the electronic transformer generally produces a fixed phase error that will compromise the measurement accuracy and require a phase shift method for correction. In this paper, we propose a digital phase shift method based on least squares fitting algorithm and derive the recursion formula of digital phase shift. The simulation has also been done to analysis its performance. The result shows that the method has high phase shift resolution and precision. By applying the method to an electronic transformer based on Rogowski coil, we have experimentally verified the feasibility and validity of the method.