Muhammad Rusydi Muhammad Razif

Two chambers soft actuator realizing robotic gymnotiform swimmers fin

This paper shows a study on two chambers soft actuator development and its application to an artificial soft actuator fin. Simulations of two chambers actuator are conducted using finite element method software and the bending angles produced are computed. Eleven designs are proposed and compared which differ in separating wall thickness, actuator thickness, fiber location, fiber materials, and rubber materials to analyze the optimal bending angle produced by the actuator. Two actuators are then fabricated and embedded at the ends of soft actuator fin to produce a traveling wave along the soft actuator fin. Soft actuator fin propels like gymnotiform swimmers and shows good linear motion.

3-D finite-element analysis of fiber-reinforced soft bending actuator for finger flexion

Towards the development of a safe, small, lightweight and human-friendly finger exoskeleton, device made from high elasticity material driven by pneumatic source; or simply known as soft actuator is currently being paid to attention. The study is to determine the optimum fiber-reinforced elastic soft actuator model to be employed in an exoskeleton for finger rehabilitation. Bending motion anticipated from a 3-D finite element actuator model is verified in the nonlinear finite element software, MARC™. The effectiveness of the proposed model is discussed based on the displacement data obtained from the large strain finite element analysis. Specific geometric properties, material properties, contact and boundary conditions related to the real experimental testing were applied to the analysis. Based on the results, the proposed model shows a good presentation of bending motion at applied pressure of 150 kPa. The behavior of bending motion which is greatly influenced by the angle of the fiber reinforced to the actuator is also discussed.

Development of Flexible Bronchoscope Device Using Soft Actuator

Flexible bronchoscope or fiber optic bronchoscope (FOB) is commonly used for airway observation in lung diagnosis because of its easy, safe, and good tolerant technique. However, during intubation, FOB may lead to get jammed due to unpassed size. A novel soft-tip FOB development using soft actuator mechanism is proposed to solve the jamming problem. The study is focused on the design, fabrication, and implementation stages. The FOB design utilized a molding system that was drawn using SolidWorks and printed using 3D printer. The FOB fabrication used the printed mold to create the soft-tip by mixing the silicone rubber with its curing agent, pouring the mixture into the mold and solidifying them into the mold. The FOB initial implementation was performed by using tube and air compressor. Fabricating two types of soft actuator twisting and bending actuator developed a flexible bronchoscope using soft actuator. The result shows that the proposed soft-tip could move close to movement requirement after standard pressure driving experiment was executed.

Determination of non-linear material constants of RTV silicone applied to a soft actuator for robotic applications

SILASTIC P-1 Silicone, a hyper elastic material, supplied by Dow Corning® is considered for the current research of the development of a soft actuator. The uniaxial tensile testing and compression testing according to ASTM standards are conducted to find its mechanical material properties. The measured stress-strain data are then applied to three kinds of constitutive non-linear models and their respective non-linear material constants are computed by least square fit. The first order Ogden model shows the better agreement with the experimental data. The mechanical properties such as ultimate tensile strength, compressive strength, shear modulus and non-linear material constants of the selected material are finally presented which will further be used for the design and analysis of the soft actuator.

Soft-amphibious robot using thin and soft McKibben actuator

This paper introduces a quadruped soft-amphibious robot using 4.0 mm diameter thin and soft McKibben actuator. The robot utilizes its leg and body bending mechanism to locomote. For each leg, three links of the actuators are arranged in parallel with fixed upper and bottom part. Then, four actuators are arranged in parallel and fixed with a thin plastic plate in between the actuators for the body motion. The elastic deformation of the plastic plate actuated by the actuators assist in the side-to-side motion of the robot mimicking the gait of the biological creature like lizard/salamander during walking motion. FEM simulation studies were performed in Marc Mentat® to evaluate the bending behaviors and validated with an experimental test. Walking experiment was tested on a flat surface and on sand using two different gaits of trot and crawl gait. On the other hand, swimming experiment was tested inside water using only crawl gait. Different input pressure and frequency were varied to study the walking behavior. The robot successfully walks on a flat and 10° incline plane with a maximum speed of 0.056 m/s using trot gait and robust to move on sand and in water using the crawl gait at 0.041 m/s and 0.022 m/s, respectively.

Non-Linear Finite Element Analysis of Biologically Inspired Robotic Fin Actuated by Soft Actuators

In this paper, a robotic fin was idealized with three rays, which are serially connected by thin flexible rubber membranes. Each ray consists a two chamber braided soft actuator operated by pneumatic pressure at the maximum of 20 kPa. The bending of the ray is achieved by alternating the supply of air to the chamber. The soft actuator bends to the right when the left chamber is pressurized and moves to the left when the right chamber is pressurized. The propulsive wave motion along the fin is thus achieved by oscillating the rays at the same frequency but in different phases. The finite element (FE) analysis was conducted in MARC®, nonlinear FE software, from which the lateral displacements of the rays and the corresponding effect on the membranes were measured. The wave amplitude of the fin was computed from the simulation results. The wave motion of the robotic fin and its corresponding pressure distributions were also observed and presented.

Numerical dynamic analysis of a single link soft robot finger

In this paper, a solid, single link soft robot finger was modeled with SILASTIC P-1 Silicone, supplied by Dow Corning®. The material is anon-linear hyper elastic, strain dependent, room temperature vulcanized (RTV) rubber. When the fingers are actuated for grasping and object manipulation, they vibrate with excessive amplitudes, which will disturb the precise positioning of the fingers. Vibration analysis through numerical simulation was conducted in ANSYS® V12. The first ten fundamental frequencies and their mode shapes were numerically computed and presented from modal analysis. The lowest natural frequency of the finger model was found to be 2.14 Hz. The dynamic stiffness of the finger model was then computed from the natural frequencies. It was found to be nonlinear in nature. The dynamic characteristics of the finger model during the excitation between 1 Hz and 1000 Hz were studied in transient analysis. The peak acceleration occurred at 9.3 Hz, while the peak velocity occurs at 3.75 Hz and 4.8 Hz with the magnitude of 0.013 mm/s.