Tactile-sensing-based robotic grasping stability analysis

Tactile signals play a crucial role in enabling robots to successfully manipulate unfamiliar objects.For robots to grasp unknown objects securely and without causing damage,it is essential that they can analyze grasping stability in real time through tactile signals and respond promptly.This study introduces a novel method for analyzing the stability of robotic hand grasping,utilizing the Wilcoxon signed rank test.The efficacy of this method is demonstrated through its static and dynamic performance,and evaluated across a series of experiments.The findings of this research highlight the method’s ability to accurately detect when an object begins to slip from the robot’s grasp.Employing this method allows the gripper to maintain a secure hold on objects by applying the minimal necessary force.It also enables the gripper to dynamically adjust the force it applies in real time,thus preventing the object from slipping during the movement of the robotic arm.Moreover,the gripper demonstrates the ability to stably grasp objects of varied weights and with unknown characteristics,showcasing the versatility and effectiveness of the proposed method.

A Bio-inspired Mutual-hook Strategy for the Soft Finger to Improve Load-bearing Capacity and Grasping Stability

Soft grippers have great potential applications in daily life,since they can compliantly grasp soft and delicate objects.However,the highly elastic fingers of most soft grippers are prone to separate from each other while grasping objects due to their low stiffness,thus reducing the grasping stability and load-bearing capacity.To tackle this problem,inspired from the venus flytrap plant,this work proposes a mutual-hook mechanism to restrain the separation and improve the grasping performance of soft fingers.The novel soft gripper design consists of three modules,a soft finger-cot,two Soft Hook Actuators(SHAs)and two sliding mechanisms.Here,the soft finger-cot covers on the soft finger,increasing the contact area with the target object,two SHAs are fixed to the left and right sides of the finger-cot,and the sliding mechanisms are designed to make SHAs stretch flexibly.Experiments demonstrate that the proposed design can restrain the separation of soft fingers substantially,and the soft fingers with the finger-cots can grasp objects three times heavier than the soft fingers without the proposed design.The proposed design can provide invaluable insights for soft fingers to restrain the separation while grasping,thus improving the grasping stability and the load-bearing capacity.

Stability Analysis of Grasps with a Robotic Multifingered Hand

Stability is a significant property for a robot hand grasp to perform complextasks similar to human hands. The common method to investigate the stability of roboticmulti-fingered grasp system is Lyapunov direct method, but usually it is rather difficult toconstruct a proper Lyapunov function. Avoiding the hard work of constructing a Lyapunov function, wepropose the sufficient conditions for stability of the robotic grasp system.