Advanced service robots and flexible production lines demand more versatile grippers than conventional ones. The traditional industrial gripper with two set of pin arrays fails to grasp some objects. This paper presented a novel universal gripper with concentric rotation pin array, CRPA gripper. It is capable of grasping various objects with only one actuator, which drives two sets of multiple concentric rings rotate at opposite directions. Analytical model of force transmission is built. Simulation results verify the feasibility of the gripper design. A functional prototype validates the predicted performance.

This paper proposes a soft robot hand with pin-array structure and self-adaptive function, CTSA-II hand, where CTSA is the Cluster tube self-adaption. The CTSA-II hand is designed with a quite concise struc ure and consists of bases, a pin array, a spring array, and a membrane. When the CTSA-II hand grasps an object, the pins will slide along the trajectory to conform to the profile of the object under the reaction force applied by the object, and thus the outer membrane will form a specific shape, and then the vacuum drives the CTSA-II hand to grasp the object. Theoretical analysis shows that the CTSA-II hand can generate enough grasping force and get good stability. Moreover, the optimization of its structure is achieved by studying the effects of specific parameters. The capture experimental results of the prototype show that the CTSA-II hand can realize self-adaptive grasping of different sizes and shapes with a high degree of fit and a high success rate. A series of research experiments show the influence of various factors on the grasping force, which verifies the results of the theoretical analysis with the CTSA-II hand. Compared to the traditional robot hand, the CTSA-II hand has good crawl performance, concise structure, small volume, and easy assembly.

Robot hand is the device used for robots to interact with the environments, it has many potential applications. Traditional robot hands cannot translate their finger end along a straight line, which makes them not suitable for grasping thin objects on a flat surface. In order to overcome the bottleneck of traditional hands and enlarge the application possibility of robot hands, this paper develops a novel hybrid grasping modes hand with the variable geometrical structure (called VGS hand). The hand consists of 4-DOF (degree of freedom), two actuators and two fingers. It can perform both linear-parallel and self-adaptive grasping modes. Kinematics, dynamics, and contact forces analysis are conducted to provide a theoretical reference for the design. A prototype was manufactured for grasping experiments; the results of the experiments indicate that the hand has a good grasping performance and can meet dierent application requirements.

Based on the motion principle of bionic earthworms, we designed and fabricated a novel crawling robot driven by pneumatic power. Its structure is divided into four segments, and its motion process is periodic with high stability. Due to the pneumatic suction cups mounted on its feet, it is able to crawl on smooth horizontal, inclined, or vertical walls. On this basis, we designed a novel underactuated steering mechanism. Through the tendons on both sides and the springs installed on the side of the robot, we accurately controlled the steering motion of the robot. We analyzed the steering process in detail, calculated the influence of external parameters on the steering process of the robot, and simulated the trajectory of the robot in the steering process. The experimental results validated our analysis. In addition, we calculate the maximum thrust that each segment of the robot can provide, and determine the maximum load that the robot can bear during climbing motions.

Purpose – Underactuated fingers are adapted to generate several grasping modes for different tasks, and coupled fingers and self-adaptive fingers are two important types of them. Aiming to expand the application and increase adaptability of robotic hand, this paper aims to propose a novel grasping model, called coupled and indirectly self-adaptive (CISA) grasping model, which is the combination of coupled finger and indirectly selfadaptive finger. Design/methodology/approach – CISA grasping process includes two stages: first, coupled and then indirectly self-adaptive grasping; thus, it is not only integrated with the good pinching ability of coupled finger but also characterized with the high flexibility of indirectly self-adaptive finger. Furthermore, a CISA hand with linkage-slider, called CISA-LS hand, is designed based on the CISA grasping model, consisting of 1 palm, 5 CISA-LS fingers and 14 degrees of freedom. Findings – To research the grasping behavior of CISA-LS hand, kinematic analysis, dynamic analysis and force analysis of 2-joint CISA-LS finger are performed. Results of grasping experiments for different objects demonstrate the high reliability and stability of CISA-LS hand. Originality/value – CISA fingers integrate two grasping modes, coupled grasping and indirectly self-adaptive grasping, into one finger. A double-linkage-slider mechanism is designed as the switch device.