Abstract - This paper is concerned with the application of a robust control approach based on Sliding Mode Control (SMC) strategy with proportional integral switching surface.. in contro[r]

In this paper, the problem of robust tracking for **robot** manipulator is considered. On the basis of **sliding** **mode** **control** theory, a class of VSC controllers for robust tracking of **robot** **manipulators** is proposed under decentralized approaches. It is shown theoretically that for system with matched uncertainties, the tracking error is guaranteed to decrease asymptotically to zero and the system dynamics during the **sliding** phase can easily be shaped up using any conventional pole placement method.

system and treat each joint of the manipulator as a simple linear servomechanism as in most of industrial robots, whereby the simple controller like Independent Joint **Control** (IJC), **proportional** plus derivative (PD), or **proportional** plus **integral** plus derivative (PID) controllers are adopted. In these methods, the nonlinear, coupled and time-varying dynamics of the mechanical linkage of the **robot** manipulator have been excluded and completely ignored, or assumed as disturbances. **Manipulators** that have been controlled by this method usually move at slow speeds with unnecessary vibrations. In general, the method is only suitable for relatively slow manipulation and limited precision tasks [11]. However, when the manipulator joints are moving simultaneously and at high speed, the nonlinear coupling effects and the interaction forces between the manipulator links may affect the performance of the overall system and increase the tracking error. The disturbances and uncertainties such as variable payload in a task cycle may also reduce the tracking quality of the **robot** manipulator system [12].

Show more
13 Read more

Line follower **robot** is mobile **robot** and has been widely used in different area. The usages of mobile **robot** are to transport material form one place to another place. Other than that, mobile **robot** also has been used in military as bomb defusing. However, the development of line follower **robot** has faced some difficulties mostly to obtain stable and precise navigation. When the speed of line follower is increased, the **robot** would not be able to navigate effectively or follow the line precisely. This is due to the slow response from the sensors, unstable wheels and other disturbances. These problems would be affecting to the performances of the **robot**.

Show more
24 Read more

The demand of Flexible Base Mobile Manipulator (FBMM) has risen in recent years and the applications are many and varied. This research proposed new Combined **Sliding** **Mode** Impedance **Control** (SMIC) for FBMM using singular perturbation method. FBMM applications include robotic manipulator mounted on the mobile vehicle in space, under water or on the land. These applications include position/force **control** requirements so on welding, cleaning, machine tooling, construction, finishing and inspection. Meanwhile, assumption of rigid base is unreal for all kind of FBMM. Impact value of mobile **manipulators** depends to both base motion and links masses which cause greater vibration on the flexible base at the contact point.

Show more
The application of adaptive neural networks to **robot** manipulator is presented in Perez et al. (2012) which explain recurrent neural networks and Lyapunov function methodology. An adaptive type-2 FLC for flexible-joint **manipulators** with structured and unstructured dynamical uncertainties have introduced in (Chaoui et al., 2012). In Abdel et al. (2011), the author has proposed fuzzy partition to the state variables based on the Lyapunov synthesis. Authors in Zeinali and Notash (2010) and Ho et al. (2009) have presented a methodology that enables the designer to systematically derive the rule base of the **control**. In Kohrt et al. (2013), authors have discussed on-line robust **control** for **robot** manipulator. This paper presents a new adaptive SMC for 2DOF **robot** manipulator; an adaptive tracking controller with a PID **sliding** surface. The adaptive SMC algorithm can estimate the value of switching gain constant (K w ) and boundary

Show more
14 Read more

The maximum error of six legs for the proposed controller is about 1mm, in other words, the position tracking results of our method are relatively crude but still sufficient in the practical applications. However, although the classical FSMC controller can satisfy the trajectory tracking performance of the 6-DOF parallel **robot**, the velocity **control** results (as in Fig. 11(b)) cannot meet the requirement of robotics for medical purpose, since the **chattering** is distinct especially in high speed situations. The reason why velocity tracking performance is so concerned in this rehabilitation practice is conducted as follows. Lower limb rehabilitation robots have to be manipulated within a wide range of speeds. In practical implementations, velocity **chattering** is highly undesirable because it may impact the plant dynamics and thus result in unforeseen instabilities, which is especially destructive in the training process. However, among researches on fuzzy **sliding** **mode** **control**, only a few considered the **chattering** characteristics of the velocity tracking **control**. In papers (36-38), the systems all realized trajectory tracking in simulation or practical environment. A cascade-**control** algorithm based on **sliding** **mode** was proposed in Ref. 27 to realize the trajectory tracking **control** of a parallel **robot**. However, the system lacked direct measurements of the velocity signal, and the velocity observer was designed using the position error, which may introduce severe noises.

Show more
24 Read more

A **robot** is an electro-mechanical device guided by computer programs and applications, and is a combination of mechanical engineering, electrical engineering and computer science. A **robot** is generally constructed and designed based on human and biological nature. The purpose of creating robots is to replace human work that is tiresome, repetitive, or dangerous. This could be military and police work, such as the manipulation of explosive devices or the access to places that are difficult to reach by humans, such as space (Moosavian & Papadopoulos, 2007) or the bottom of the sea (Salvador et al., 2013), due to extreme environments which humans are unable to survive. Due to the limited working space, the first robotic surgery was successfully performed by two main robots called McSleepy and DaVinci, which allowed the surgeon to work with delicate and precise hand movements of fingers that would be impossible to be done by humans alone (Science Daily, 2010).

Show more
47 Read more

In this paper, a simulink library is presented for modelling **robot** manipulator functionalities and how the trajectory will follow the end effector manipulator input and what is the difference between desired and the actual trajectories. This model based approach supports with only revolute joints and excludes the Prismatic joints. In future, the other variants like mobile robots, spherical and parallel robots can be developed. The library currently does not include blocks to perform **robot** dynamics. There are other variants of stationary robots, for example, cylindrical **robot**, spherical **robot** and parallel **robot**; and mobile robots, for example, wheel **robot** and legged **robot**, which Model Rob Library currently does not support. The main objective of this paper is to show that the model-based development approach can be successfully applied to the development of **robot** software and to motivate development of exhaustive library to cover all variants of robots.

Show more
tion **mode** transformation of a mobile **robot** with wheel-arms. The proposed method aims at transformation from a four-wheeled **mode** for high speed mobility to an inverted pendulum **mode**, which has advantages of high viewing position and small turning radius. Since the initial state of the system is far away from the target equilibrium point of the wheeled inverted pendulum system, we use a nonlinear controller based on **sliding** **mode** **control**. In contrast that the previous transformation methods cannot **control** the **robot** velocity until the **robot** body is lifted up, the proposed method can take into account the **robot** velocity from the beginning of the transformation, which enables to complete the transformation in a smaller space. To analyze the asymptotic stability of the **control** system on the **sliding** surface, we derive an invariant set in which the system state converges to the origin without going out. Furthermore, the effectiveness of the proposed method is demonstrated in both simulations and real **robot** experiments.

Show more
10 Read more

Abstract—A simple PS adaptive **integral** **sliding** **mode** controller is designed for the pitch channel linear model of supersonic missile firstly. In order to improve the performance of the proposed method, two improvements also proposed. Finally, a hybrid PISS adaptive **control** is formed which contains proportion **control**, integration **control**, the sign function adn soft function. Also nurmerical simulations are done to the testify the above theory. And it shows that both the proportion **control** and sign function **control** methods are unable to achieve a satisfactory performance for supersonic missile system. And the integration of soft function , **integral** **control** item and proportion **control** can solve the **chattering** problem and static error problem. At last, simualtion figures shows that the PISS mehtod also has a strong robustness, which is testified by increasing or decreasing air-coefficients of the missile system .

Show more
2.5 Dynamic 110del Of A Three dof Revolute Robot Manipulator 78 2.5.1 Dynamic Equation Of The Mechanical Linkage 78 2.5.2 Derivative Of The Mechanical Link Torque 85 2.5.3 Model Of The D[r]

307 Read more

According to the mechanical structure and operation principle of differential-drive two-wheeled **robot**, and aiming at the nonlinear systems with uncertainties variable structure, a trajectory tracking model based on **sliding** **mode** **control** (SMC) was designed by utilizing state vector to establish the model of system and controller. The simulating results show that **robot** can track line, circle and S shape trajectories well, which gave reasonable dynamic responses, adjustment performance, as well as perfect disturbance rejection. The system can eliminate errors according to the deviation from **sliding** surface by switching the structure of controller and is robust to external disturbance.

Show more
Electro-**hydraulic** servo (EHS) system has emerged a great interest in various engineering applications due to its advantages as an actuator in providing high forces with compact design [1]. The sophisticated design of EHS system with the versatility of electronic and **hydraulic** components offers a great performance and improvement for wide range of applications such as aircrafts [2], manufacturing machines [3], fatigue testing [4] and automotive application [5]. It is established that the EHS system can be more well-known and crucial nowadays.

Electro-**hydraulic** actuator (EHA) systems have grown to be one of the most popular actuators in modern applications for several decades. EHA systems can be found easily in production assembly lines, robotics, automotive, aircraft, submarine operations, mining processes, etc. This is due to the fact that EHA systems have fast and smooth response characteristics and high power density. EHA systems also have excellent capability in positioning that gives a significant influence to the above applications especially in position tracking **control** issues. However, as introduced in Yao et al. (2000), EHA systems exhibit highly nonlinear behaviours, such as nonlinear servo valve flow-pressure characteristics, variations in **control** volumes, dead-band, stiffness, internal leakage, and associated friction. Apart from the nonlinear natures, parametric uncertainties, uncertain nonlinearities and disturbances also become large extent of EHA systems. Hence, consideration on these issues to obtain more accurate model in the modelling of EHA systems is essential.

Show more
43 Read more

In addition, parameter estimation has been identified as one of the ways, through which the accuracy of MSMC can be improved. Hybrid optimization is quite well-known in many application [11][12]. Several studies have proposed the combination of GSA and PSO it was through such studies, it was learnt that the combination of PSO and GSA is capable of providing improved results for general mathematical functions [13][14]. However, both have looked into the generic algorithms and it has yet to be specifically applied to estimate the parameters of MSMC controller for mismatched disturbance system such as an electro-**hydraulic** actuator such as the case in the present study[15][14]. More importantly, no studies, at least to the knowledge of the researcher, have considered looking into parameters estimation for MSMC to enhance its accuracy and performance.

Show more
The study of fault tolerant **control** (FTC) has received much attention in the last decade. Many different schemes have been proposed, ranging from active to passive **control** methods [1], with applications running the gamut from large scale petrochemical plants to automotive and aerospace systems [2]. The work in [1], [2], [3], [4] provides an excellent literature review on the different schemes used for FTC including different applications; however, research into FTC has been significantly driven by problems encountered in the safety critical aerospace industry. This is due to the practical requirement for increasing safety as well as lowering operational costs. Many different FTC methods, specific to aircraft applications, have been proposed including linear approaches (e.g. H ∞ [5], LQG [6], model-following [7], multiple model [8], model predictive **control** [9]), and nonlinear approaches (e.g. nonlinear dynamic inversion [10], backstepping [11], neural networks [12], **sliding** **mode** [13]). Some of these methods have attracted the attention of industry and have been further tested and evaluated in order to assess their potential for future applications and implementations on aircraft (see for example the European study on state-of-the-art FTC by the GARTEUR AG-16 group [14] and the recent ADDSAFE project [15]). However many of these proposed FTC schemes are based on linear plant representations and are therefore only valid in the vicinity of the designed trim point. Therefore, one of the main challenges for practical implementation, especially for aircraft, is to ensure good performance for a wide range of operating conditions. Some of the linear based designs can be extended to handle variations in operating conditions (see for example, gain scheduling and linear parameter varying (LPV) schemes [16], [17]), but direct nonlinear methods such as nonlinear dynamic inversion (NDI) and backstepping provide equally viable alternatives – with many benefits compared to the extended linear cases. One obvious benefit is the direct exploitation of the well known aircraft equations of motion, which provide good and consistent performance throughout the flight envelope.

Show more
17 Read more

In order to make the spherical underwater **robot** better finish the task of underwater operation, the good **control** system and **control** method are essential. Researchers have proposed a variety of motion **control** methods, and the **control** algorithms of underwater which have been applied: PID **control**, improved PID **control**, fuzzy **control**, adaptive **control**, **sliding** **mode** **control**, neural network **control**, robust **control**, and some combination of these **control** algorithms. **Sliding** **mode** **control** (SMC), which is robust to model uncertainty and to parameter variations, and it has good disturbance rejection features. There have been a wide variety of applications of it [4,5,6,7,8,9,10,11] . However, it inherits a discontinuous **control** action and hence **chattering** phenomena will take place when the system operates near the **sliding** surface. Sometimes this discontinuous **control** action can even cause the system performance to be unstable. Fuzzy **Control** (FC) has supplanted conventional technologies in many applications. One major property of fuzzy logic is its ability to express the amount of ambiguity in human thinking. Therefore, when the mathematical model of the process does not exist, or exists but with uncertainties, FC is an alternative way to deal with the unknown process. However, the huge number of fuzzy rules for high-order systems makes the analysis complex [12,13,14,15] . The system used in this paper is a combination of fuzzy **control** and the **sliding** **mode** **control**.

Show more
1. Soon, C. C., Ghazali, R., Jaafar, H. I. and Hussein, S. Y. S., 2015. "Optimizing PID Controller for an Electro-**hydraulic** Servo System via Gradient Descent Technique," Proceedings of Mechanical Engineering Research Day 2015 (MERD'15), 31 Mac, Melaka, Malaysia. (Indexed by Thomson Reuters, Web of Science)

24 Read more