6.2 Result of generation of ribbon shape

The starting configuration was with the ribbon hanging straight down. Figure 14 shows a composite photograph in which the circle shape was produced. In Figure 14, the dotted white line depicts the reference shape of the ribbon (i.e., the robot trajectory), and these pictures were taken at intervals of 0.067 s. Figure 15 Toward Dynamic Manipulation of Flexible Objects by High-Speed Robot System: From Static… DOI: http://dx.doi.org/10.5772/intechopen.82521

Figure 12.

Continuous sequence of photographs of dynamic knotting. (a) t = 0.00 [sec], (b) t = 0.16 [sec], (c) t = 0.32 [sec], (d) t = 0.48 [sec], (e) t = 0.64 [sec] and (f) t = 3.20 [sec] [17].

#### Figure 13.

Desired rope configuration and joint trajectories of the robot arm. (a) Desired rope configuration, (b) Rotation axis of the upper arm, (c) Circulation axis of the upper arm and (d) Rotation axis of the lower arm [17].

shows an error between the reference circle shape and the actual ribbon shape. The error is calculated by a square root of sum of square error of each direction. As can be seen from these figures, the circle shape of the ribbon was successfully produced. We also produced a figure-eight shape, a wave shape, and a crank shape in the ribbon [18].

Figure 14. Composite photograph of shape generation [13, 18].

Figure 15. Error between reference and actual shapes [13, 18].

The error between the reference shape and the obtained shape was evaluated for each reference shape.

#### 6.3 Result of dynamic folding of a cloth

Next, we show the experimental result for dynamic folding of a cloth [14] shown in Figure 16. Figure 17 shows the trajectories of the slider and hand wrists, and Figure 18 shows the experimental data (visual information). Figure 16(a) represents the initial condition of the experiment, where the two hands grasp the cloth. Figure 16(b)–(c) shows the cloth being pulled toward the grasp position using the hand and slider motions. Figure 16(d) shows that when the hand and slider motions stop, the free end (the point far from the grasp position) of the cloth is folded by inertial force. Figure 16(e)–(f) shows grasping of the free end of the cloth using high-speed visual feedback [19]. As can be seen from the experimental results, dynamic folding of the cloth can be achieved by the two high-speed multi-fingered hands and two high-speed sliders. In addition, since the action time of the dynamic folding performed by the robot system is 0.4 s, high-speed folding can be achieved.

Toward Dynamic Manipulation of Flexible Objects by High-Speed Robot System: From Static… DOI: http://dx.doi.org/10.5772/intechopen.82521

#### Figure 16.

Continuous sequence of photographs of dynamic folding. (a) Time = 0.0 [sec], (b) Time = 0.1 [sec], (c) Time = 0.2 [sec], (d) Time = 0.3 [sec], (e) Time = 0.4 [sec] and (f) Time = 0.5 [sec] [19].

Figure 17. Trajectories of slider and hand wrist. (a) Trajectory of slider and (b) Trajectory of wrist of hand [19].

Figure 18. Experimental data of dynamic folding. (a) Area of markers and (b) Y position of markers [19].

#### 6.4 Result of rope insertion

Figures 19 and 20 show the experimental result and data during rope insertion experiment. From the experimental results, the rope is deformed by the effect of gravity in the initial state as shown in Figure 19(a), but the rope deformation could be successfully controlled to a linear shape using the high-speed rotation motion.

Figure 19.

Continuous sequence of photographs of rope insertion task. (a) Initial state, (b) Finish state, (c) 2.0 [s], (d) 2.40 [s], (e) 2.75 [s], (f) 2.82 [s], (g) 2.90 [s] and (h) 2.95 [s] [15].

Figure 20.

Experimental data of rope insertion. (a) Angular feature, (b) Angular feature error and (c) Image coordinate x-y [15].

Consequently, we achieved the rope insertion task with the proposed method, as shown in Figure 19(b).

#### 6.5 Result of pizza dough spinning

Figures 21 and 22 show the experimental result and data during pizza dough spinning experiment. It can be seen that the deformation of the pizza dough could Toward Dynamic Manipulation of Flexible Objects by High-Speed Robot System: From Static… DOI: http://dx.doi.org/10.5772/intechopen.82521

Figure 21.

Continuous sequence of photographs of pizza dough spinning. Normal camera; (a) t = 0.00 [s], (b) t = 0.33 [s], (c) t = 0.67 [s], (d) t = 1.00 [s], High-speed camera; (e) t = 0.04 [s] and (f) t = 0.12 [s] [16].

Figure 22.

Experimental data of pizza dough spinning. (a) x-position of pizza dough and (b) y-position of pizza dough [16].

be controlled to approximately a planar shape by the proposed method, and the angular acceleration of the rotation could be achieved using the high-speed finger motion with contact control by high-speed image processing.

Summarizing this section, high-speed motion and real-time visual feedback allowed us to perform dynamic manipulation of flexible objects in a rotational motion system.

## 7. Conclusion

We have proposed a new method for dynamic and high-speed manipulation of flexible objects. The proposed method includes constant, high-speed robot motion and real-time visual feedback control. The findings described in this chapter can be summarized as follows:

A. The constant, high-speed robot motion contributed to the construction of a simple deformation model of flexible objects (expressed by an algebraic equation).


Our proposed method will bring about a paradigm shift in which the flexible object strategy changes from static or quasi-static to dynamic.

In the future, we plan to demonstrate dynamic manipulations of flexible objects other than the tasks we explained in this article.
