Accurate and Efficient Dynamics for Variable-Length Continuum Arms: A Center of Gravity Approach

To achieve their full potential, soft and compliant continuum robots must move faster and more accurately than they can today. To facilitate this, accurate and computationally efficient dynamic models are essential. While the integral Lagrangian approach can produce accurate models, it is complex and computationally intensive. In this article we propose a new dynamic model based on numerically stable modal kinematics that is both accurate and computationally efficient. The proposed model is a lumped parameter model, but one that is more accurate than prior lumped parameter models because mass locations and quantities are derived from a detailed description of the total energy in a continuum arm with continuously distributed mass. We experimentally validated the model using a pneumatic muscle-actuated continuum arm, and the proposed model successfully simulates the transient and steady-state dynamics of the prototype arm. Further, the model is also compared to the integral Lagrangian and a lumped parameter model to highlight its advantages in terms of computational efficiency and its accuracy.