Development of a 3D Printed Soft Parallel Robot

This paper reports on design, fabrication, and kinematics modeling of a 3D printed soft parallel robot equipped with soft pneumatic actuators. Soft robotics is an emerging field of research which facilitates safe human machine interface. Soft elastomeric actuators made through molding process are one of the key elements of soft robotic systems. However, molding process is tedious and time consuming making the fabrication process undesirable. Recently reported 3D printed soft pneumatic actuators pave the way for manufacturing of novel soft actuators and robots with complex geometries. The current work can be considered as a proof of concept for 3D printing of a soft parallel robot. The robot consists of two soft pneumatic actuators that are connected to two passive links by mean of flexible hinges. The robot has two degrees of freedom and can be used in planar manipulation tasks. Moreover, a number of robots can be configured to operate in a cooperative manner to increase the manipulation dexterity. Application of parallel mechanism instead of serial mechanism introduce several advantages including: reduction of the adverse effect of inertial disturbances, better control on overall stiffness of the robot structure, and elimination of pneumatic tubing which is needed for actuation of sequential actuators in a serial mechanism. Although the proposed robot has two degrees of freedom, the design strategy can be extended to three-dimensional robots with more degrees of freedom. The robot can be 3D printed in different scales using polymers with different stiffnesses to facilitate different manipulation tasks and payloads. Since, the robot is made of soft material it can safely cooperates with humans in wide range of medical and industrial tasks. The soft robot is 3D printed using Form 2 printer and Elastic resin. It has been shown that the orientation of the robot structure with respect to the build plate is key parameter in printing process to make sure that the uncured polymers will naturally flow out of the robot cavities. In order to, actuate the robot it is connected to two syringe pumps to control the motion of the soft actuators. A kinematic model is developed to simulate the motion of robot end-effector. Through application of the kinematic model it has been shown that the robot is capable of following any planar trajectories within its workspace. Future work involves development of static and dynamic model of the soft robot to more accurately predict the robot interaction with its environment and also develop advanced control system for robust position control of the robot.