Transactions of the Institute of Measurement and Control

Wang, Nan; Lin, Weiyang; Yu, Jinyong; Zhang, An; Ye, Chao

doi: 10.1177/0142331216674068pmid: N/A

In this paper, an observer-based sliding mode controller is proposed for a high-accuracy motion plant to suppress the disturbances and improve the tracking performance. In particular, a two time-scale separation technology, which can recover the disturbance state in a faster time scale, is utilized to compensate the disturbances and improve the system robustness. The parameter identification is carried out to obtain the model coefficients with a high fitting rate. Such an identified model can allow the engineers to tune the controller’s gains highly enough when the system suffers from the measurement noises. Instead of the traditional low-pass filter, a differentiator is introduced for the velocity signal prediction and its discrete-time version is provided to attenuate the noises effect. To verify the effectiveness of the proposed approach, an adaptive robust control law is compared with the proposed one in terms of dynamic positioning error, robustness and rapid signal tracking, and the superiority and advantages can be illustrated by the experimental results.

Chen, Zheng; Pan, Ya-Jun; Gu, Jason; Forbrigger, Shane

doi: 10.1177/0142331216679500pmid: N/A

Multilateral teleoperation systems, which are extended from the traditional bilateral teleoperation, have become subject to increasing attention in current years, with increasing industrial requirements, such as the remote operation of larger objects and more complex tasks. In this paper, a general multilateral teleoperation control problem is discussed, in which n masters remotely control n slaves through delayed communication channels. A novel communication structure is proposed to satisfy the multiple master–slave communication requirement, in which weighting coefficients are chosen freely to perform the weighted effects of different masters or slaves. Power-based time-domain passivity control is subsequently developed for the complex multiple master–slave communication channel, to achieve the passivity of multilateral teleoperation systems under time delay. Experiments on a teleoperation system with two masters and two slaves are described; the results verify the effectiveness of the proposed control scheme.

Li, Minhan; Kang, Rongjie; Geng, Shineng; Guglielmino, Emanuele

doi: 10.1177/0142331216685607pmid: N/A

Continuum robots are suitable for operating in unstructured environments owing to their intrinsic compliance. This paper presents a novel tendon-driven continuum robot equipped with two modules and a compliant backbone formed by helical springs. Each module is driven by four parallel arranged tendons to implement a redundant actuation system that guarantees dexterous motions of the robot. A position feedback controller for the continuum robot is then developed, and a quadratic programming algorithm is incorporated into the controller to achieve a smooth configuration of the robot. Experiments results show that the control method has good trajectory tracking performance against external disturbances.

Banthia, Vikram; Maddahi, Yaser; Zareinia, Kourosh; Liao, Stephen; Olson, Tim; Fung, Wai-Keung; Balakrishnan, Subramaniam; Sepehri, Nariman

doi: 10.1177/0142331216687021pmid: N/A

This paper reports technical design of a novel experimental test facility, using haptic-enabled teleoperation of robotic manipulators, for live transmission line maintenance. The goal is to study and develop appropriate techniques in repair overhead power transmission lines by allowing linemen to wirelessly guide a remote manipulator, installed on a crane bucket, to execute dexterous maintenance tasks, such as twisting a tie wire around a cable. Challenges and solutions for developing such a system are outlined. The test facility consists of a PHANToM Desktop haptic device (master site), an industrial hydraulic manipulator (slave site) mounted atop a Stewart platform, and a wireless communication channel connecting the master and slave sites. The teleoperated system is tested under different force feedback schemes, while the base is excited and the communication channel is delayed and/or lossy to emulate realistic network behaviors. The force feedback schemes are: virtual fixture, augmentation force and augmented virtual fixture. Performance of each scheme is evaluated under three measures: task completion time, number of failed trials and displacement of the slave manipulator end-effector. The developed test rig has been shown to be successful in performing haptic-enabled teleoperation for live-line maintenance in a laboratory setting. The authors aim at establishing a benchmark test facility for objective evaluation of ideas and concepts in the teleoperation of live-line maintenance tasks.

Feng, Zhang

doi: 10.1177/0142331217697373pmid: N/A

The problem considered in this paper is the robust integrated translation and rotation control for spacecraft rendezvous in unstructured environments. The pursuer spacecraft considered is equipped with a single main thruster, capable of only providing thrust along one axis of the body frame, and attitude control actuators, capable of providing manoeuvrability in three axes of the body frame. The formulated coupled translational and rotational dynamics of the spacecraft with various uncertainties performs an under-actuated highly nonlinear system. A technical state transformation is then proposed to transform the coupled dynamics into a cascaded nonlinear system with the first subsystem being a linear perturbed system. This special cascaded nonlinear structure inspires the synthesization of the eigenstructure assignment parametric technique and the backstepping philosophy to guarantee not only robust closed-loop stability but also a robust trajectory tracking performance in the presence of various system uncertainties coming from unstructured environments. Moreover, rigorous closed-loop stability analysis is undertaken by using singular perturbation theory. Finally, a space interception is used to demonstrate the effectiveness of the proposed control scheme.

Hu, Lili; Wang, Xinyong; Li, Hongmin

doi: 10.1177/0142331217707368pmid: N/A

This paper investigates the primary problem of distributed consensus for Euler–Lagrange systems networked by using non-uniform sampling information with probabilistic transmission delay. In a real-world application, the information is likely to be exchanged in a discrete-time interval manner. Employing sampled-data information can save the energy cost and reduce the communication network burden. For the reasons given above, sampling control is applied in this paper. Meanwhile, we focus on the study of non-uniform sampling information exchanges in the communication network which is described in this paper. In order to verify the distributed consensus of Euler–Lagrange systems, matrix theory, algebraic graph theory and Lyapunov stability theory are applied. A distinctive feature of this paper is that the transmission delay is defined as the probability of time-varying delay. A numerical simulation is given to demonstrate the benefits and effectiveness of the proposed schemes.

Shen, Wei; Su, Xiaoyu; Pang, Yu; Zhao, Ruihan

doi: 10.1177/0142331217707369pmid: N/A

In this paper, a new kind of rule called Active Regulating Common Pressure Rail (ARCPR) for hydraulic system is presented. Especially, the main focus is to improve the control performance for the swing hydraulic system with the parametric uncertainties and time delay effect caused by employing ARCPR. Firstly, the traditional CPR is introduced and the energy saving potential is analyzed. Then, the mathematical model of the displacement regulating system and swing driving system is presented. Moreover, the displacement regulating system model is simplified by considering the parametric uncertainties and time delay condition. Furthermore, a robust controller is designed to meet the system requirements. Finally, a simulation based on standard working condition is conducted and the result shows the control performance can meet the practical requirement well.

Wang, Jialiang; Ding, Jianli; Cao, Weidong; Li, Quanfu; Zhao, Hai

doi: 10.1177/0142331217713837pmid: N/A

Recently, the quad-rotor helicopter has gained increasing attention owing to its very good flexibility, its ability to execute various flight missions even in harsh environments. The quad-rotor helicopter can implement different fight attitudes, which is attributed to the effective control of the motor speed about four propellers. In order to make the quad-rotor helicopter can better finish flight mission, the performance of flight stability then becomes particularly important. A neural network fuzzy control algorithm is proposed in this paper so as to guarantee the stability performance of the quad-rotor helicopter. The proposed algorithm is based on the neural network, which keeps the self-organization and self-learning ability, besides this, it utilizes the strong impression ability of constitutive knowledge as to the fuzzy logic. The proposed control scheme aims to implement good abilities such as describing qualitative knowledge, strong learning mechanism and direct processing about quantitative data of the quad-rotor helicopter. In the practical flight process of the quad-rotor helicopter, while the deviation of position and attitude information become larger, fuzzy control is adopted so as to shorten the overshoot and adjustment time. On the other hand, if the deviation of position and attitude become relatively smaller, neural network PID control will be used so as to reduce the error. Experimental results show that the proposed neural network fuzzy control algorithm exhibits good performance in the flight process of the quad-rotor helicopter.

Sun, Zhenxing; Li, Shihua; Wang, Jiegao; Zhang, Xinghua; Mo, Xiaohui

doi: 10.1177/0142331217719956pmid: N/A

With the development of digital signal processes, the relative differences of PMSM single loop in control periods between the speed loop and current loops are becoming smaller or even vanishing. Therefore, cascade control schemes seem to be unnecessary. In addition, considering the effects of disturbances and the variety of moments of inertia, this paper proposes a scheme using an adaptive non-cascade control method to design the controller, which merges speed loop and q-axis current loop into one single loop. First, an extended state observer (ESO) is employed to estimate the disturbances of the system. The estimated value is used in the feedforward compensation design to improve the capability of system anti-disturbance. Then, considering the performance degradation caused by inertia change, an adaptive control scheme is developed. By using inertia identification technology, the feedforward compensation gain can be tuned automatically according to the identification value. Several groups of simulations and experiments are carried out and the results demonstrate the effectiveness of the proposed scheme.

Su, Qingyu; Zhu, Haichao; Li, Jian

doi: 10.1177/0142331217746626pmid: N/A

In this paper, the H∞ control problem for linear state-constrained switched systems via the improved mode-dependent average dwell time method is investigated. Using this proposed method, which considers different decay rates of a Lyapunov function related to an active subsystem on the basis of whether there is saturation or not, the resulting minimum admissible mode-dependent average dwell time is smaller than that of the traditional average dwell time method, which assumes a constant decay rate, regardless of whether there is saturation or not. Thus, this method is less conservative than the traditional average dwell time method. In addition, this paper outlines the design of the state feedback controller of the switched systems, which guarantees that the closed-loop linear state-constrained switched system is globally asymptotically stable and obtains a weighted L2 gain. The availability and applicability of the proposed method are shown by the application of a boost converter.