Hybrid System Analysis and Control of a Soft Robotic Gripper with Embedded Proprioceptive Sensing for Enhanced Gripping Performance

Abstract

Soft robots are considered to have infinite degrees of freedom based on their structural compliance, providing high adaptability to the environments, and recent study has focused mostly on advancement of their physical designs for increasing the adaptability. However, interaction itself with the environment has not been taken into serious account in previous studies despite the importance in applications. A soft robot as a hybrid system described by both discrete and continuous states is considered and a method of analysis for enhanced manipulation is proposed. The method is tested with a soft gripper composed of a pneumatic bending actuator and an embedded soft sensor for a task of object gripping. The optimum sensor location on the actuator based on the calibration map obtained from the actuator characterization is first determined. Using the sensor information, the interaction with the environment (i.e., object) classified into four discrete states is understood. In addition, a control strategy to find the best position to grip the object based on the estimated states is developed. The gripper is able to successfully complete the task using the proposed method for three test scenarios with different initial conditions and control parameters. Finally, the results are demonstrated with supporting videos.

Modeling and Control of a Soft Robotic Fish with Integrated Soft Sensing

“…This study combines the pneumatically actuated system presented in Jusufi et al [44] with the strain sensors used in Park et al [45,46] and implements closed-loop control of swimming using entirely soft sensors and actuators. Time-lapse sequence images of the robotic fish undulatory locomotion are provided in Figure 1.…”

Assisting Forearm Function in Children With Movement Disorders via A Soft Wearable Robot With Equilibrium-Point Control

“…Another direction is developing an analytical model via hybrid dynamical systems theory to understand the stability bounds in terms of the equilibrium-point controller parameters. A similar model has been applied to proprioceptive soft grippers ( Park et al, 2021 ). Additionally, a more comprehensive study with human participants, including the participation of control subjects, would provide further opportunities for understanding the device’s influence on muscle coordination, skill acquisitions, and object manipulation.…”

“…To the degree possible, in order to minimize space, complexity, and manufacturing cost, it is desirable to minimize the need for sophisticated electromechanical sensors, motivating new techniques for perception. In fact, inherent compliance can be leveraged for proprioception, that is, an intrinsic sense of the kinematic configuration, thereby reducing the need for other sensor modalities ( Wirekoh et al, 2019 ; Chen W.-H. et al, 2020 ; Park et al, 2021 ). Since external forces change the volume (therefore the internal pressure) of the actuator, a pressure sensor can readily detect the interaction.…”

Body Caudal Undulation Measured by Soft Sensors and Emulated by Soft Artificial Muscles

“…This makes them especially suitable for measuring movements that are inspired by animal locomotion and performed by soft robotic platforms and to detect contacts made by external environments, as demonstrated by artificial proprioceptors ( Wirekoh et al. 2019 ; Park et al. 2020 ) and mechanoreceptors ( Kim et al.…”