Evolving Honeycomb Pneumatic Finger In Physics Engine

The robot technology has made great progress in the past few years, and it’s widely used in industry, education, medicine and home service. However the application of the hard robots which are made of hard material and depend on the motor drive still meets many restrictions. Rigid robots cannot adapt to the environment well such as moving on the outside uneven ground, passing through the pipe and grabbing the smooth sphere. Soft robots have become a new research hotspot because of its compliance with the surroundings and friendly interactive with the environment. However, most of the soft robots are designed and fabricated by the researchers’intuition and experience, which lack of systemic theoretical analysis, such as the analysis of stress and deformation. It requires a large number of experiments to validate the assumptions. The cost of time and material of the research is very high. When in the absence of suitable materials to fabricate soft robots, the control algorithms can hardly be verified. So it’s very necessary for researchers to have a functional simulation platform.In this paper we construct a soft honeycomb pneumatic finger, which is composed of embedded honeycomb pneumatic network. It aims at grasping rigid ball through controlling the variation of its inner pressure. It overcomes the shortcoming of easily rupture and highly required of the toughness of the material. In the meantime, in order to analyze the effect of the aerodynamic changing to the shape of the finger, we also establish a theoretical model and a physical simulation model, which is as the extension part of Bullet soft dynamic simulation. In the theoretical model, we establish a pressure-shape model according to the characteristic of the deformation along with the changing pressure. In the physical simulation model, we use the form of mass-link to represent honeycomb pneumatic finger, mapping the macroscopic deformation to the microscopic changing of the link constraint, thus building the relationship among the pressure, deformation and the link constraint. We can use this simulation platform to simulate the dynamic deformation of this pneumatic finger in3D environment. We also implement the dynamical collision detection method between soft finger and rigid body.Based on this work, without the need to consider the selection and processing of materials, we can complete the analysis of the pressure-deformation of the virtual pneumatic finger. Subsequently we use the pneumatic finger without any rigid joints and motors to construct a virtual hand which is simulated with the use of open source physics engine Bullet. Through the control of inner air pressure of the pneumatic unit the finger can achieve bending and thus the virtual hand can grasp a spherical object obediently. If we apply our work in the impeccable robot simulation platform, making it supporting the simulation of soft components of robots, it will provide very useful validation and analysis tool. Finally we give the error analysis between the theoretical model and physical simulation model and the prospects of soft robot simulation platform based on our work.