Sliding mode

Figure 5.39 The three modes of crack surface displacement (a) opening mode (b) sliding mode and (c) tearing mode.

Fig. 3. A sphere model (a) illustrates the tip paths encountered during the lateral manipulation on a fcc(lll) metal surface, (b) Single atom manipulation signals taken on a Ag(lll) surface show a sudden transition from various pulling modes to a sliding mode at = 30° [5],...

An intriguing finding from this experiment is the observation of a sudden transition from the pulling mode to the sliding mode when the atom is manipulated along the [211] direction of Ag(lll) surface. 

This detailed picture of the movement of the atom during manipulation was achieved with the aid of simulations [6]. The atom moves in a local potential minimum on the surface. This potential is the sum of the surface potential and the tip potential. The surface potential can be expressed by the migration barrier while the tip potential describes the direct interaction via chemical or electrostatic forces. The local potential minimum is not identical with the adsorption site, in the limit of close tip-atom separation this minimum always resides below the tip resulting in the sliding mode. The atom is slowly pushed/pulled by the tip out of the adsorption site until it jumps into the next local potential minimum. The jump to the next potential minimum proceeds on a timescale of picoseconds [7,8] whereas typical tip speeds are of the order of 0.5-2.5nm/s. 

The first term is symmetric in 0, while the second is skew symmetric and they repre nt the opening Mode I and sliding Mode II of crack loading, respectively. Mode I is essentially that for loading normal to the crack, while Mode II is that for shear loading. Since Mode I is by far the most common, we shall confine our attention to the first term which is usually expressed as ... 

Figure 7. Polymer chain in contact with a free interface the chain loops formed between the contact points are supposed to exhibit a sliding-mode motion.

The interleaving of the two flow paths proposed by Nunes is illustrated in the plan view showninFig. 3.12. Similar macrostructures have been observed in welds of dissimilar metals (Ref 23). The occurrence of stick-slide modes due to the interface between the weld tool and the work-piece would explain the origin of interleaving. The residue of the straight-through current metal flow predominates on the RS and the upper... 

Susceptibility to interlaminar failure is a major weakness of advanced laminated composite materials. It can occur by in-plane shearing (i.e., sliding) (mode II). and out-of-plane shearing (i.e.. tearing) (mode III) as well as by tensile (mode I) deformation. Mode II loading is of particular interest, as values have been shown to correlate with compression after impact data [142.143]. which is required for such purposes as civil aircraft certification. 

Here, we limit our attention to scenarios where 0, which essentially eliminates combinations of materials with comparable—but not identical—stiffness. Note that is identically zero for identical materials. When jS 0 the crack tip fields are analogous to those in a homogenous material (i.e., the crack tip stresses scale as Oy 1 / ) and Kj and Kjj dictate the contributions of opening and sliding displacements, respectively (or normal and shear stresses). If 0, the opening and sliding modes are coupled and crack advance criteria require additional parameters [31,32],... 

Durfee, W.K. and DJ. DiLorenzo, Sliding mode control of FNS knee joint motion. Abstr. First World Cong. Biomech., 1990,2 329. 

Smicker. D. Van Smaalen. S.V. de Boers. J.L. Haas. C. Harris. K.D.M. Observation of the sliding mode in incommensurate intergrowth compounds Brillouin scattering from the inclusion compound of urea and heptadec-ane. Phys. Rev. Lett. 1995, 74. 734. 

Vertical contact-separation Contact-sliding mode... 

Control system Drive control Sliding mode control... 

This entry presents feed drive control systems used in modem CNC machine tools. Considering the rigid body motion of the feed drive, widely used control algorithms such as P-Pl and PID control are being introduced. At last, the sliding mode control algorithm is presented and its performance against the conventional PID control is shown. 

Sliding Mode Control Algorithm In contrast to the conventionally used P-Pl and PID control algorithms, a more robust sliding mode control algorithm has been introduced to... 

The experimental results are presented in Fig. 3. It clearly indicates that the weU-tuned sliding mode controller (SMC) gives significantly less contouring and tracking errors as compared to a standard PID controller. 

Altintas Y, Erkorkmaz K, Zhu W-H (2000) Sliding mode controller design for high speed drives. Ann CIRP 49(l) 265-270... 

Sliding Mode Control for Path Tracking of Underground Mining Articuiated Dump Truck... 

An autonomous controller for an underground mining truck is presented in this paper. The controlled truck is an articulated type with 4 electric drive motors. Dynamic model of this truck including steering and 4-wheel differential control is setup. A sliding mode control law is proposed for asymptotically stabilizing the truck to a desired trajectory. It is shown that the proposed scheme is robust to bounded external disturbances. Experimental results on Hardware-in-the-loop demonstrate the effectiveness of accurate tracking capability and the robust performance of the proposed scheme. 

SLIDING MODE CONTROL FOR TRACKING OF DUMP TRUCK... 

While n is the dimension of state variables, x is an n-dimension column vector, C is -dimen-sion row vector of control law. SMC should drive system to the sliding mode surface s = 0. 

Aslam, J., S. Qin, and M.A. AM, 2014, Fuzzy sliding mode control algorithm for a four-wheel skid steer vehicle Journal of Mechanical Science and Technology, v. 28, p. 3301-3310. 

Korayem, M.H., H. Tourajizadeh, M. Jalali, and E. Omidi, 2012, Optimal path planning of spatial cable robot using optimal sliding mode control International Journal of Advanced Robotic Systems, v. 9. 

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