Closed-loop Position Control of a Pediatric Soft Robotic Wearable Device for Upper Extremity Assistance

Abstract

Soft robotics hold promise in the development of safe yet powered assistive wearable devices for infants. Key to this is the development of closed-loop controllers that can help regulate pneumatic pressure in the device's actuators in an effort to induce controlled motion at the user's limbs and be able to track different types of trajectories. This work develops a controller for soft pneumatic actuators aimed to power a pediatric soft wearable robotic device prototype for upper extremity motion assistance. The controller tracks desired trajectories for a system of soft pneumatic actuators supporting two-degree-of-freedom shoulder joint motion on an infant-sized engineered mannequin. The degrees of freedom assisted by the actuators are equivalent to shoulder motion (abduction/adduction and flexion/extension). Embedded inertial measurement unit sensors provide real-time joint feedback. Experimental data from performing reaching tasks using the engineered mannequin are obtained and compared against ground truth to evaluate the performance of the developed controller. Results reveal the proposed controller leads to accurate trajectory tracking performance across a variety of shoulder joint motions.

Safely catching aerial micro-robots in mid-air using an open-source aerial robot with soft gripper

“…Third, the project uses the basic on-off control for the gripper with constant inflating rates. It is of interest to incorporate feedback control of the soft end-effector as in Mucchiani et al (2022) . Fourth, we aim to deploy the robot in outdoor or confined environments without a motion capture system, thus enabling vision guidance as in Kim et al (2016) and impact resilience as in Liu and Karydis (2021b) .…”

“…In recent years, there is a growing interest in developing nonmilitary tools to capture aerial robots in mid-air with applications to recover malfunctioning aerial robots and intercept and contain unidentified flying targets Park et al (2021). Physically catching flying robots in mid-air is challenging due to their irregular shapes and self-propulsion.…”

“…Despite the proved effectiveness, these solutions primarily focus on catching aerial robots with diagonal sizes (including propellers) over 500 mm (e.g., DJI1 Mavic Pro and Phantom 4). However, little attention is paid to capturing flying micro-robots such as Crazyflie2 2.1 with diagonal sizes around 100 mm, which are relatively more challenging to detect and intercept Park et al (2021). In addition, capturing by nets involve relative motion to targets that will inevitably create impact and possibly damage target robots.…”

Koopman Operators for Modeling and Control of Soft Robotics

“…In contrast to their rigid counterparts, soft robots have bodies made out of intrinsically soft/or extensible materials, which exhibit unprecedented adaptation to complex environments and can absorb impact energy for safe interactions with the environment, other robots, and even humans [1]. Soft robots have been applied in all aspects of robotic research, including but not limited to assistive robotics [2]- [4], grasping [5]- [7], ground mobility [8], [9], legged locomotion [10], [11], aerial robots [12] and underwater robots [13].…”

“…Due to the infinite degrees of freedom of soft robots, accurate firstprinciples-based models are hard to derive. Moreover, in most cases, system nonlinearities pose additional difficulties to controller design [4]. One way to resolve such constraints is by considering data-driven methods [35], [36].…”