Parallel robots exhibit superior precision to serial robots. They operate with reduced power consumption due to load distribution among individual motors. However, symmetrical parallel robots employing a 1T2R structure encounter challenges with parasitic movements at the end-effector, leading to control complexities and application limitations. This study aimed to downsize the robot while ensuring its operational range by employing origami techniques. Addressing the inherent weakness of origami’s stiffness, various methods of material stacking and designed joints with diverse materials and thicknesses were proposed to meet specific angle requirements for each component. The developed control model was validated through simulations and experiments, effectively minimizing parasitic movements by verifying the robot"s motion.

This paper presents a distortion compensation algorithm for cable-driven master devices. Such device has four string pots at four corners of a frame. Four cables are tied from the four corners to the center holder. When the central holder, which is a haptic grip, moves, lengths of the four cables will change. From the four cable lengths, the spatial position of the haptic grip can be estimated using triangulation. In this case, distortion such as barrel image of the image field occurs when estimating a position with an offset parallel to the plane in which the four string pots are located. The closer to the corner, the smaller the position estimate value is than the true value. After distortion phenomenon is modeled by projecting onto the ellipsoid, the position in the vertical direction of the cable plane is compensated by the corresponding value and flattened. The mean error in the x-direction position was improved by 91% from 0.7833±0.8381 mm to -0.0709±0.4341 mm. This cable-driven master device can be used as a haptic device for operating a surgical robot.