0 −2 (b) −1 0 1 510 20 3015 Time [s] 25 f d (t) and f(t) 0 −15 −10 −5 0 10 15 5 5 10 20253015 Time [s] Parameter m e +m r d e +d r k e +k r d e k e Figure 16.14 Simulation results on the time responses of the robot’s force (the blue lines) tracking a time varying desired force (the green lines), and the parameter convergences of the feedforward controller. The environmental viscosity is set from 2 to 0.5 at the time t = 250[s] in (a) and t = 15[s] in (b). At the beginning 100(s), 250(s) to 350(s) in (a) and the beginning 4(s) in (b), the desired forces are set as noises. 0 −0.4 −0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 51020304050453525 Time [s](a) f d (t) and f(t) f d (t) f(t) 15 0 −0.4 −0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 51020304050453525 Time [s](b) f d (t) and f(t) f d (t) f(t) 15 Figure 16.15 Time responses of the force tracking control experiments of a robot interacting with its unknown dynamic environment. The experimental setup is in Figure 16.11. Here, (a) is the result when using usual constant feedforward þ PI feedback control (23), while (b) is the result of 2 D.O.F. adaptive control (41). The feedback control of (b) is used as same as that in (a). (a) Experimental result using PI control; (b) experimental result of adaptive control. Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 25 21.9.2005 9:38pm Sclera Choroid Retina Optic nerve Cornea Pupil Lens Iris Ciliary body Figure 17.1 The human eye in cross section with an enlarged section of the retina (right). The light sensitive retina covers more than half the back of the eye. Over 100 million photoreceptors convert light into neural signals that are then transmitted to the proximal visual centers by the optic nerve. The optic nerve is composed of 1 million axons from the retinal ganglion cells, which are the output cells of the retina. In outer retinal diseases, the photoreceptors are degenerated, but the inner retina cells remain and can be electrically stimulated. Figure 18.1 ELAD artificial liver system. (Courtesy of Vital Therapies Inc; San Diego, CA.) Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 26 21.9.2005 9:39pm Figure 18.6 HeartMate II rotary axial pump device. (a) (b) (c) Figure 18.7 (a) Novacor VAD, (b) cross-section of Novacor, and (c) diagrammatic representation of Novacor, (With permission from WorldHeart Corporation, Ottawa, Canada.) Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 27 21.9.2005 9:40pm Figure 18.9 MicroMed DeBakey ventricular assist device. (With permission from MicroMed Technology, Inc; Huston, TX.) Figure 18.12 The SynCardia CardioWest total artificial heart (With permission from SynCardia Systems, Inc.; Tucson, AZ.) Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 28 21.9.2005 9:41pm Figure 19.9 A stable, erect sunflower stem (left panel) depends on the pressure of internal, easily expandable hydrostat tissue (pith ¼ transparent cells in center panel) that tensions the stronger-walled surface layers of the stem giving them rigidity and stability. The well-known limp shape of wilting young plant stems (right panel) occurs when the internal, thin-walled pith tissue dehydrates, shrinks (center panel) and ceases to exert radial pressure on the surface layer under tension. Left panel shows fully hydrated sunflower stem and right panel a dehydrated stem; the center panel demonstrates volume reduction in pith during dehydration of a segment slice. Pith parenchyma acts as a hydrostat motor that provides herbaceous stems with stability and the driving force for expansion. Figure 19.13 Leaves of Venus flytraps have large, powerful motor cells in their center. The rapid expansion of these cells is modified by different extensibilities of the two adjacent surface (epidermis) layers. These anisotropic restraints turn a linear expansion into the rapid curving of the leaf and closure of the trap. This mechanism is triggered when the sensory hairs at the upper surface are repeatedly touched. Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 29 21.9.2005 9:42pm Figure 19.18 The shoots of desert plants in the Cactus and Euphorbia families often adopt the shape of pleated columns (a) a structure which allows the photosynthesizing periphery to maintain its area in spite of massive volume losses in the shoot center. Cross sections of a pleated-column shoot show increasing dehydration from upper to lower pictures (b) with a considerable volume loss of the shoot center (c) and remarkably constancy in the area of a surface that changes its shape from a convex to a concave outline. Figure 20.2 A four-legged robot called STAR (Steep Terrain Access Rover) is under development at JPL. (Courtesy of Brett Kennedy, JPL.) Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 30 21.9.2005 9:43pm Figure 20.3 The Singaporean giant ‘‘durians’’ building called the Esplanade Theater (left) has the shape of this fruit that is considered the King of fruits (right). (The photo on the right is the courtesy of Anand Krishna Asundi, Nanyang Technological University, Singapore.) Figure 20.5 Grand challenge for the development of EAP-actuated robotics. Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 31 21.9.2005 9:43pm Figure 20.6 The chain of evolution of our mimicking nature is drawn into the artificial world that we create. (Top graphics is the courtesy of David Hanson, and Human Emulation Robotics, LLC. The bottom graphics is the modification that was made by Adi Marom, Research Artifacts Center Engineering, The University of Tokyo, Japan. The robotic arm in this figure was made by G. Whiteley, Sheffield Hallam U., U.K., and photographed in the author’s lab.) Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 32 21.9.2005 9:44pm Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 33 21.9.2005 9:45pm . the author’s lab.) Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 32 21.9 .20 05 9:44pm Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color. the upper surface are repeatedly touched. Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 29 21 .9 .20 05 9:42pm Figure 19.18 The shoots of desert plants. Singapore.) Figure 20 .5 Grand challenge for the development of EAP-actuated robotics. Bar- Cohen : Biomimetics: Biologically Inspired Technologies DK3163_color plates Final Proof page 31 21 .9 .20 05 9:43pm Figure