An effective nonlinear dynamic formulation to analyze grasping capability of soft pneumatic robotic gripper

Figures & data

The configuration variations and von Mises stress distribution of the SPG at different moments.

Figure 1. The structural design of a three-jaw SPG. (a) a soft pneumatic bending actuator after inflation, (b) sectional view of the actuator, (c) a base, (d) the SPG and a ball in a still state, (e) the construction and components of the SPG, (f) the SPG and the ball in grasping state.

Table 1. Description of specific parameters of the three-jaw SPG.

Detailed explanation	Parameters	Magnitude
Length of soft actuator	L	44 mm
Width of soft actuator	W	20 mm
Height of soft actuator	H	17 mm
Height of internal air chambers	H1	13 mm
Thickness of air chamber walls	t	1 mm
Length of solid section	t1	10 mm
Interval between adjacent contact walls	t2	2 mm
Length of each air chamber	t3	6 mm
Length of front air chamber	t4	8 mm
Side length of base	l	42 mm
Width of base	w	30 mm
Thickness of base	h	4 mm
External length of rectangular slot	L1	23 mm
Internal length of rectangular slot	L2	20 mm
External width of rectangular slot	W1	20 mm
Internal width of rectangular slot	W2	17 mm
External height of rectangular slot	h1	10 mm
Internal height of rectangular slot	h2	8 mm

Figure 2. The surface element of air chamber walls.

Figure 3. Closet point projection procedure.

Figure 4. The contact pair. (a) Configuration of contact pair with frictional contact, (b) Tangential slipping of the projection point m on the master surface.

Figure 5. Simulations and experiments of a single soft pneumatic actuator. (a) The proposed model’s result, (b) ABAQUS result, (c) the experimental result, (d) Comparative results.

Figure 6. The applied pressure load.

Figure 7. The configurations and von Mises stress of the SPG and displacement variations of the ball at different moments. (a) t = 0.0 s, (b) t = 0.7 s, (c) t = 3.0 s, (d) t = 4.0 s, (e) t = 5.0 s, (f) t = 6.0 s.

Figure 8. The displacement versus time of the ball in two time periods. (a) t = 0.0 s ~ 3.0 s, (b) t = 3.0 s ~ 6.0 s.

Figure 9. The ball subject to diverse forces. (a) Normal contact force, (b) Tangential frictional force, (c) Resultant force.

Table 2. Different forces in the process of uniform linear motion.

Description	Parameters	Magnitude
The gravitational force of the SPG	GSPG	0.6292 N
The gravitational force of the ball	GB	0.3685 N
The concentrated force	FC	1 N

Figure 10. The experimental equipments.

Figure 11. Grasping the ball experiment. (a) t = 0.0 s, (b) t = 0.7 s, (c) t = 3.0 s, (d) t = 4.0 s, (e) t = 5.0 s, (f) t = 6.0 s.

Figure 12. The displacement of the ball in Y direction in two time periods. (a) t = 0.0 s ~ 3.0 s, (b) t = 3.0 s ~ 6.0 s.

Figure 13. The deformation configuration and von Mises stress distribution of the SPG at t = 2.5 s.

Figure 14. The motion states of the ball and von Mises stress distribution of the SPG at (a) t = 0.0 s, (b) t = 2.0 s, (c) t = 3.0 s and (d) the displacements of the ball.