In this study, we proposed an origami pump actuator based pneumatic quadruped robot (OPARO). The robot was constructed with a four-leg system controlled by only two motors. Specifically, the forelegs and hindlegs are pneumatically coupled to operate simultaneously with a tendon-driven system. The forelegs simultaneously performs pumping and actuating to supply air to the hindlegs, and the hindlegs are passively actuated by the air supply from the forelegs. We conducted a series of experiments to evaluate the mobility performance of OPARO. We measured the posture of each leg and analyzed the movement to determine the operating mechanism in locomotion. The motion, gait, and repeatability of OPARO were analyzed from the experimental results. Additionally, we conducted a parametric study to determine the tendencies at different gait frequencies and motor inputs. The OPARO moves at a maximum velocity of 0.11 body length per second (10.29 mm/s). Furthermore, we evaluated the gait velocity with various gait patterns according to different duty ratios and floor surfaces. Moreover, the steering performance of OPARO was demonstrated. We found that the tendon-driven pneumatic origami pump actuator system is adequate for a quadruped robot without an external air supply system.

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In this study, a wearable multifunctional additive hand (MAH) system is proposed for enhancing the workspace and grasping capability of the human hand. The MAH system consists of a main body and three fingers, and each finger has two joints. To optimize the performance, the following five parameters are considered: finger length, number of fingers, number of joints, base frame size, and joint angle range. The MAH system is designed to assist the human hand in the inward and outward modes. In the inward mode, the finger joints of the proposed system rotate in the same direction as the finger flexion of the human hand, whereas in the outward mode, the robotic fingers of the MAH system rotate in opposite directions. The proposed system provides assistive torque and expands the workspace of the human hand in the inward mode. When the additive finger joints rotate outward, they grasp an object as a third hand. The validity of the proposed system is verified analytically by changing the design parameters, considering the workspace expansion and joint torque reduction. An alpha shape is introduced to calculate the expanded workspace volume using the proposed system. The joint torque was estimated by utilizing kinematics and the force equilibrium equation, assuming that the human hand with the MAH system holds a postulated object.INDEX TERMS Grippers and other end-effectors, human performance augmentation, multifingered hands, physically assistive devices, wearable robotics.