A Passive Power-Based Control Strategy for pHRI Tasks With Omni-Directional Robotic Mobile Platforms

Mobile robotic platforms have gained increasing popularity across various fields; however, achieving intuitive physical interaction between these robots and humans remains an ongoing area of exploration. In this study, we proposed a novel variable admittance model designed for robotic mobile platforms. The proposed admittance model achieves the decoupling of the desired dynamics related to the intended motion direction from that of the unintentional motion, ensuring that changes in one space do not affect the other. In the unintentional space, the admittance parameters remain constant, while the inertia and damping gains along the intended motion direction are adjusted to provide compliance to the human user. The design of these variable terms was performed to ensure a consistent response, aiming to offer a perceived consistent behavior to the human user and to guarantee strict passivity under human force input, ensuring manipulation stability. In addition to theoretical proof of passivity, we validate the effectiveness and performance of the proposed control scheme through experimental results using an omni-directional robotic mobile platform.