A soft gripper is a type of robotic end-effector, or “hand,” designed to interact with objects using flexible, compliant materials. Unlike rigid robotic tools, these grippers are constructed from soft substances like silicone or other elastomers, allowing them to deform and conform to various shapes. This design enables a gentle touch, reducing the risk of damage to the objects they manipulate.
Mechanism of Soft Grippers
Soft grippers achieve their flexibility through their materials and actuation methods. Common materials include silicone rubber, such as Ecoflex or Dragon Skin, and thermoplastic polyurethanes (TPUs), chosen for their stretchability, durability, and tear resistance. These materials allow the gripper’s “fingers” or body to bend and twist significantly.
The primary method of operation for many soft grippers involves pneumatic actuation. Internal channels or chambers within the gripper’s soft structure are inflated or deflated with air pressure. As air enters these chambers, they expand, causing the gripper’s segments to bend or curl inward, grasping an object. Releasing the air allows the gripper to relax its grip.
Contrasting with Rigid Grippers
Traditional rigid grippers operate with precise, pre-programmed movements and exert high forces to secure objects. They are designed for specific, uniformly shaped items, often requiring reprogramming or tool changes for different tasks. This design can lead to damage when handling fragile or irregularly shaped items.
Soft grippers, in contrast, conform to an object’s unique geometry, providing a secure yet gentle hold. Their inherent compliance reduces the need for exact positioning and complex programming, making them highly adaptable to a variety of shapes and sizes. This flexibility also enhances safety when robots work alongside humans, as the soft materials absorb impact and minimize injury risk.
Practical Uses of Soft Grippers
Soft grippers are finding widespread use across various industries. In the food and beverage sector, they are employed for picking delicate produce like strawberries, tomatoes, or baked goods such as bread and pastries. Their hygienic, food-grade materials also make them suitable for handling meat, poultry, and packaging items like bottles and cans.
Manufacturing benefits from soft grippers, especially when handling sensitive components. They can safely manipulate delicate electronics, glass, or other fragile parts during assembly and sorting processes. This adaptability allows for flexible production lines where the same gripper can handle diverse products.
The medical field also leverages soft grippers for specialized tasks. These tools can assist in minimally invasive surgical procedures, allowing surgeons to grasp and manipulate delicate tissues or organs. They are also being developed for rehabilitation devices, helping patients with limited hand mobility, and for handling biological samples in laboratory settings.