Robotic end-effectors for manufacturing: Recent developments and future research challenges

Industrial robots excel at replicating human movements, with robotic arms mimicking the human arm and end-effectors replicating the hand. While robot arm designs offer versatility, end-effectors, typically designed for specific tasks, lack this flexibility. Despite numerous review papers focusing on specific applications or aspects of robotic end-effectors -such as agriculture, surgery, space, grinding, or control methods - a clear gap remains: the lack of a comprehensive review that integrates design, modeling, and control across diverse manufacturing applications. This paper reviews the state-of-the-art in robotic end-effectors, exploring their design variations and the enabling technologies that power them. The review categorises end-effectors based on their applications, including finishing, machining (traditional and non-traditional), additive manufacturing and grasping end-effectors. In each category we highlight the key design considerations for optimal performance. Beyond their application-specific designs, the paper explores the enabling technologies that shape end-effector capabilities. Sensors, the "eyes and ears," provide crucial information on the environment through force sensors and vision systems. Actuators, the "muscles," convert electrical signals into movement using pneumatics, hydraulics, or increasingly popular electric mechanisms. The paper concludes by discussing the modelling and control aspects of end-effectors. Kinematic, dynamic, and stiffness models are explored as crucial tools for designing and analysing these versatile tools, ensuring optimal functionality, accuracy, and efficiency. Finally, control tools act as the conductor, orchestrating the entire operation, and translating commands into real-time actions. This review emphasises the importance of end-effectors in expanding robot capabilities and highlights the intricate interplay of design and enabling technologies that drive their development.