Journal of Intelligent & Fuzzy Systems - Volume 31, issue 6

Authors: Gong, Yanbing | Yang, Sunxin | Dai, Liangliang

Article Type: Research Article

Abstract: In order to aggregate all uncertain information of the footprint of uncertainty (FOU) and improve the speed of defuzzification for interval type-2 fuzzy sets (IT2 FS), the normal ordered weighted averaging (NOWA) weighted sampling method is proposed to transform an IT2 FS into a type-1 fuzzy set (T1 FS), whose defuzzified values closely approximate those of the expected values of all embedded T1 FSs. Compared with the existing methods, the proposed method is more simple and practical, and the result is mainly determined by the numbers and weights of random samples in each vertical slice of FOU. Finally, based on …the NOWA weighted sampling method, a new possibility degree is introduced to solve multi-attribute decision-making problems in which the attribute values take the form of interval type-2 fuzzy numbers. Show more

Keywords: Interval type-2 fuzzy set, type-reduction, normal OWA weight, sampling

DOI: 10.3233/JIFS-169176

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 2927-2933, 2016

Authors: Zhang, Cong | Zhang, Jun

Article Type: Research Article

Abstract: We discuss the interpolation strategies related to Richardson extrapolation and repeated Richardson extrapolation. We emphasize that, in most computations, the interest is in obtaining accurate solution on the current computational grid, not that on the coarse level grids on which the extrapolated solutions reside. We tackle the interpolation issue that has largely been overlooked in Richardson extrapolation related applications. We present numerical experiments to support our analysis.

Keywords: Computational grid, finite difference scheme, Richardson extrapolation, interpolation, high order solution

DOI: 10.3233/JIFS-169177

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 2935-2939, 2016

Authors: Song, Shujie | Qu, Jiwei | Li, Yining | Zhou, Wei | Guo, Kangquan

Article Type: Research Article

Abstract: In this paper, we study a four-wheel, individual steering and four-wheel, individually driven, electric chassis, named the flexible chassis. A 2-FOF nonlinear steering model for the flexible chassis is established based on the “magic formula” tire model and the Ackermann steering theorem at low speed. Also, a new control method based on the fuzzy strategy is proposed for its sideslip angle control. The left front-wheel steering angle is inputted into the simulation of the vehicle, and the left-rear wheel angle is controlled by the fuzzy controller to make the sideslip angle zero. Also, the remaining steering angle of the other …two wheels, which meet the Ackermann theorem, are adjusted. Comparisons between simulations of the front-wheel steering, four-wheel, proportional steering and the newly proposed steering indicate that the new control algorithm in this paper is effective. Show more

Keywords: Electric vehicle, fuzzy control, four-wheel independent steering, four-wheel independent driving, simulation

DOI: 10.3233/JIFS-169178

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 2941-2948, 2016

Authors: Bai, Keqiang | Luo, Minzhou | Li, Tao | Wu, Jue | Yang, Lei | Liu, Manlu | Jiang, Guanwu

Article Type: Research Article

Abstract: This paper proposes a new controller based on the torque compensation method for the control of a 7-DOF dual-arm of a humanoid robot with input saturation residual vibration of the end-effector. Through theoretical and experimental analysis, an adaptive fuzzy backstepping control strategy was designed for the 7-DOF dual-arm control system. This strategy can be used to suppress the time-varying nonlinear residual vibration of the end-effector caused by inertia variations in the serial robot. Firstly, a boundary feedback controller was designed to asymptotically stabilize the closed-loop system based on the C 0 -semigroup theory, which also proves the efficacy of the …closed-loop system solution. Lyapunov stability analysis proved that the closed-loop demonstrated globally asymptotic stability. Secondly, an adaptive fuzzy backstepping method was designed for the dynamic compensator with a tracking filter for the control system of the 7-DOF dual-arm of the humanoid robot. The primary difference between this new method and conventional methods is that the new method does not require complex computation. In addition, this method improves the limit of computing power and memory space for the controllers. Finally, the effectiveness of the torque compensation strategy and the new method’s ability to suppress the residual vibration are demonstrated via simulation and experiments. Show more

Keywords: Torque compensation, 7-DOF dual-arm of humanoid robot, input saturation, adaptive fuzzy backstepping control

DOI: 10.3233/JIFS-169179

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 2949-2957, 2016

Authors: Wang, Monan | Sun, Lei | Yang, Ning | Mao, Zhiyong

Article Type: Research Article

Abstract: In this study, a fracture-healing model based on the mechanical environment and blood supply conditions was proposed to simulate and predict the complex regenerative repair process for tissues. A three-dimensional finite element model was established to describe fracture callus mechanics based on tetrahedral units. The blood perfusion was regarded as a spatio-temporal state variable and was included into the model to simulate a revascularization process. The dynamic model described the callus mechanics and biological processes of tissue differentiation by using a combination of a finite element method and fuzzy logic. The callus healing process was simulated time-discretely by an explicit …Euler integration iterative loop over equidistant time steps and was implemented via Visual Studio 2012. Finally, the model predicted the value of interfragmentary of two groups with different axial stabilities. A comparison of the results with the experiment data indicated that the simulation results were distributed within the scope of the average deviation of the experimental data, and this corresponded well with the experiment trend and numerical value. The agreement between the simulation results and experimental results verified the accuracy of the fracture-healing model and demonstrated its advantages for simulating healing process. Show more

Keywords: Fracture healing, three-dimensional model, fuzzy rules, tissue differentiation

DOI: 10.3233/JIFS-169180

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 2959-2965, 2016

Authors: Gao, Zhenhai | Wang, Jun | Hu, Hongyu | Sun, Yiteng

Article Type: Research Article

Abstract: The control mode switching strategy is a crucial part of the Adaptive Cruise Control (ACC) decision algorithm. A novel switching strategy of control mode is proposed, which is designed using an intuitionistic fuzzy set, multi-attribute decision making method (IFSMADM). At first, three modes of cruising, following and approaching are considered for the control modes of the decision algorithm for the ACC. Then, safety performance, comfort performance and economy performance are treated as the attributes needed to assess alternative sets. Furthermore, the linear weighted average method of IFSMADM is used to achieve control mode switching. Finally, the proposed algorithm is verified …based on actual road test data. Show more

Keywords: Adaptive Cruise Control (ACC), switching strategy, intuitionistic fuzzy set, multi-attribute decision making

DOI: 10.3233/JIFS-169181

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 2967-2974, 2016

Authors: Tao, Yong | Xie, Guang | Chen, Youdong | Xiong, Hegen | Liu, Hui | Zheng, Jiaqi | Gao, Jinpeng

Article Type: Research Article

Abstract: This paper proposes a quadrotor aircraft motion control method based on the combination of PID and a fuzzy control algorithm. The dynamical system of quadrotor aircrafts is modeled. Target colors are recognized and tracked based on the OpenCV. The target-following flight attitudes of the quadrotor is controlled by a fuzzy PID control algorithm. We focus on exterior, unknown, interfering factors, such as gusts, and adjust k p , k i , k d parameters online in real time. This allows the response speed of the quadrotor flight control system to increase and improves the anti-jamming capability …for the exterior non-linear factors. The simulation of the control system is accomplished with the Matlab/Simulink, and the real flight tests are based on the Parrot AR Drone 2.0 quadrotor aircraft, which verifies the effectiveness of the proposed method. The proposed method is able to improve the adaptability of the quadrotor for exterior, environmental changes, shorten the system adjustment time and improve the following accuracy of the quadrotor. Show more

Keywords: Quadrotor aircraft, machine vision, fuzzy PID control algorithm, pose control

DOI: 10.3233/JIFS-169182

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 2975-2983, 2016

Authors: Zhang, Fei | Zong, Shengyue | Li, Xiaozhan | Chen, Handan

Article Type: Research Article

Abstract: A closed-loop control system for the hydraulic gap control (HGC) that is driven by electrohydraulic servo valves is developed for practical application. Based on the mathematical model estimated by a system identification technique, the control algorithm is designed, and the fuzzy inference rules are established. The simulation and field test results of the step response and the position tracking that is carried out on the HGC system of a cold rolling mill show that when compared with the conventional PID control system, the self-tuning fuzzy PID system has the characteristics of fast response, short rise time, no lag, small overshoot, …and strong anti-interference ability. At the same time, the self-tuning fuzzy PID control algorithm can not only improve the position tracking ability of the HGC system, but can also tune the servo valve to overcome the nonlinearity of the HGC system. Show more

Keywords: System identification, hydraulic gap control, position control, self-tuning, fuzzy PID

DOI: 10.3233/JIFS-169183

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 2985-2997, 2016

Authors: Pang, Hui | Liu, Fan | Liu, Xue

Article Type: Research Article

Abstract: An enhanced variable-universe fuzzy controller design approach is proposed for a vehicle semi-active suspension system that combines the conventional universe fuzzy control algorithm with the fuzzy neural network control theory. First, a mathematical model of a vehicle suspension system is established, taking the road excitation into account. Then, a fuzzy inference unit is constructed by using a fuzzy neural network algorithm, which is able to regulate the universe of input/output variables for a fuzzy logic controller in real-time. It can also avoid the problem of excessive reliance on expert experience in selecting the contracting-expanding factors. Finally, a designed example and …its simulation analysis are conducted to verify the proposed control approach. Show more

Keywords: Semi-active suspension, variable-universe, fuzzy control, fuzzy neural network

DOI: 10.3233/JIFS-169184

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 2999-3006, 2016

Authors: Chang, En-Chih

Article Type: Research Article

Abstract: This paper describes an adaptive neuro-fuzzy (ANF) nonsingular terminal attractor (NTA) that can control output voltage in an AC power conditioner. The NTA experiences the convergence of the system trajectory to zero within finite time, and it can avoid singularity problems. However, when the estimated value exceeds or falls short of the uncertain system boundary, chattering or steady-state error problems occur. Therefore, the ANF technique is introduced as a computationally rapid and mathematically simple means of reducing the chatter and steady-state errors occurring in NTA if the estimated value of the uncertain system boundary is not met. The Lyapunov theory …proves that the proposed AC power conditioner is stable and convergent. Associating NTA with the ANF technique provides the AC power conditioner with low distortion and fast transience in the presence of various loading. Experimental results from a 1 kW prototype confirm the mathematical analyses and simulations. Because the proposed AC power conditioner offers significant advantages over the classic terminal attractor (TA)-controlled AC power conditioner in terms of complexity and ease of implementation, this paper represents a useful reference for designers of artificial intelligence. Show more

Keywords: Adaptive neuro-fuzzy (ANF), nonsingular terminal attractor (NTA), AC power conditioner, singularity problem, chattering

DOI: 10.3233/JIFS-169185

Citation: Journal of Intelligent & Fuzzy Systems, vol. 31, no. 6, pp. 3007-3012, 2016