One of the biggest problems with soft robots is precisely the fact that they are soft. Indeed the softer they are, the less force they can exert on the environment. Researchers have proposed a number of stiffening methods, but all of them have drawbacks, such as locking the shape of the device in a way that precludes further adjustments. In this paper we propose a stiffening method inspired by the internal structure of the mammalian penis. The soft actuation chamber is divided into small compartments that trap the actuation fluid, leading to locally amplified pressure increase under certain conditions. At the same time, the proposed solution does not affect the actuation mechanism, allowing the actuator to be adjusted in one direction just as if it was in non-stiffened mode, while offering a stiff response in the opposite direction. Our prototype achieves an increase in stiffening of approximately a factor of two. The paper describes the concept, the mathematical justification of the working principle, the prototype design, its implementation and our experimental results.

Many modern roboticists take inspiration from biology to create novel robotic structures, including those that are modeled after the octopus. This paper advances this trend by creating soft robots modeling the complex motion patterns of octopus tentacles employing a bio-mimetic approach. The proposed octopus robot is entirely made from soft material and uses a novel fluidic actuation mechanism that allows the robot to advance forward, change directions and rotate around its primary axis. The paper presents the robot's design and fabrication process. An experimental study is conducted showing the feasibility of the proposed robot and actuation mechanism.

The human hand is a complex structure. It is strong but precise. It consists of a very complex mechanical structure that enables the hand to adapt and efficiently handle objects of various shapes, weights and textures. Today's prosthetic devices, struggling to provide similar functions, become overly complex and expensive. They are composed of multiple, precise parts, including miniaturised actuators and sensors as well as complex control, to satisfy the manipulation tasks required. In this paper we propose a soft pneumatic hand that adapts passively to the handled object due to its mechanical compliance. It is pressure driven and enables individual fingers to be controlled independently for dexterity or in groups when a synergistic finger movement is needed. The hand has a truly anatomical shape, is easy to replace and cheap in production. The design can be easily adjusted in terms of shape and size in order to fit each individual user. The paper presents the design, manufacturing technology, current control system and preliminary tests of the hand's capabilities.

Soft robotic structures might play a major role in the 4thindustrial revolution. Researchers have successfully demonstrated advantages of soft robotics over traditional robots made of rigid links and joints in several application areas including manufacturing, healthcare and surgical interventions. However, soft robots have limited ability to exert higher forces when it comes to interaction with the environment, hence, change their stiffness on demand over a wide range. One stiffness mechanism embodies tendon-driven and pneumatic air actuation in an antagonistic way achieving variable stiffness values. In this paper, we apply a beam-mechanics-based model to this type of soft stiffness controllable robot. This mathematical model takes into account the various stiffness levels of the soft robotic manipulator as well as interaction forces with the environment at the tip of the manipulator. The analytical model is implemented into a robotic actuation system made of motorised linear rails with load cells (obtaining applied forces to the tendons) and a pressure regulator. Here, we present and analyse the performance and limitations of our model.

The constantly increasing amount of machines operating in the vicinity of humans makes it necessary to rethink the design approach for such machines to ensure that they are safe when interacting with humans. Traditional mechanisms are rigid and heavy and as such considered unsuitable, even dangerous when a controlled physical contact with humans is desired. A huge improvement in terms of safe human-robot interaction has been achieved by a radically new approach to robotics - soft material robotics. These new robots are made of compliant materials that render them safe when compared to the conventional rigid-link robots. This undeniable advantage of compliance and softness is paired with a number of drawbacks. One of them is that a complex and sophisticated controller is required to move a soft robot into the desired positions or along a desired trajectory, especially with external forces being present. In this paper we propose an improved soft fluidic rotary actuator composed of silicone rubber and fiber-based reinforcement. The actuator is cheap and easily manufactured providing near linear actuation properties when compared to pneumatic actuators presented elsewhere. The paper presents the actuator design, manufacturing process and a mathematical model of the actuator behavior as well as an experimental validation of the model. Four different actuator types are compared including a square-shaped and three differently reinforced cylindrical actuators.

MRI compatibility, which often is a requirement for the new medical soft robot projects, greatly reduces available actuation methods and sensors. An example of such project is STIFF-FLOP, which aims to develop a soft silicone manipulator actuated by pressure. The current arm construction and method of actuation cause several undesirable effects, which pose problems for actuation and sensing. In this paper, the authors identify the source of those negative effects and propose improvements over the current construction to eliminate or limit their influence. The new construction concept is tested and compared with the current one. Possible ideas for further development are also proposed.