Unified Kinematic and Dynamical Modeling of a Soft Robotic Arm by a Piecewise Universal Joint Model
This work addresses the problem of improving modeling accuracy for soft robotic arms in robotics, offering a more effective solution for handling external forces and gravity, though it is incremental relative to existing methods.
The paper tackled the challenge of accurately modeling soft robotic arms under external forces and gravity by developing a unified kinematic and dynamical model based on a piecewise universal joint approach, achieving maximum position and rotation errors 6.7x and 4.6x lower than the widely used Piecewise Constant Curvature model.
The compliance of soft robotic arms renders the development of accurate kinematic & dynamical models especially challenging. The most widely used model in soft robotic kinematics assumes Piecewise Constant Curvature (PCC). However, PCC fails to effectively handle external forces, or even the influence of gravity, since the robot does not deform with a constant curvature under these conditions. In this paper, we establish three-dimensional (3D) modeling of a multi-segment soft robotic arm under the less restrictive assumption that each segment of the arm is deformed on a plane without twisting. We devise a kinematic and dynamical model for the soft arm by deriving equivalence to a serial universal joint robot. Numerous experiments on the real robot platform along with simulations attest to the modeling accuracy of our approach in 3D motion with load. The maximum position/rotation error of the proposed model is verified 6.7x/4.6x lower than the PCC model considering gravity and external forces.