There are many instances of helical mechanisms that are used to efficiently grasp different objects with various shapes and sizes in nature. Inspired by the helical grasping in the nature, we proposed a helical bistable soft gripper with high load capacity and energy saving. An off-the-shelf bistable steel shell (BSS) as the stiff element was inserted into a 3D printing soft helical exoskeleton to achieve coiling around and holding the objects without energy consumption. Two air pouches were designed as the actuator to control the transition between the two stable states. To facilitate gripper design, a simplified model of the gripper was conducted, and the geometric parameters of the gripper are listed in a table for reference. The transition pressures between the two stable states were experimentally characterized. Moreover, we conduct experiments to demonstrate the capability of the gripper in two working modes. The gripper exhibits coiling diameters ranging between 40 mm and 60 mm and is successfully attached to various slender objects of different geometries with a maximum holding force of 92.67 N (up to 135.1 times of its mass) in hanging mode. Finally, the gripper was integrated into a robot arm and successfully grasped different objects, and the maximum grasping weight is 221.6 g in the grasping mode.

The robot-assisted endovascular catheterization system (RAECS) has the potential to address some of the procedural challenges and separate interventionalists from the X-ray radiation during the endovascular surgery. However, the employment of robotic systems is partly changing the natural gestures and behavior of medical professionals. This paper presents a RAECS that augments surgeon's motions using the conventional catheter as well as generates the haptic force feedback to ensure surgery safety. The magnetorheological fluids based haptic interfaceexperiment is proposed to measure the actions of the operator and provide the haptic force. The slave catheter manipulator is presented to actuate the patient catheter in two degrees of freedom (radial and axial direction). In addition, a force model is provided to characterize the kinematics of the catheter intervention. Afterward, the “pseudocollision” and “real collision” are utilized to descript the catheter tip–vessel interaction. Thein vitroresults are presented, which demonstrate that catheter-based haptic force feedback has a benefit for improving catheterization skills as well as reducing the cognitive workload of operators.