Soft Grippers
Revolutionizing mobile manipulation by mimicking the adaptability of biological systems. Soft grippers enable AGVs to handle delicate, irregular, and varied inventory with a compliance that rigid actuators simply cannot match.
Core Concepts
Mechanical Compliance
Unlike rigid claws, soft grippers deform around the target object. This passive adaptation reduces the need for sub-millimeter positioning accuracy by the AGV.
Fluidic Actuation
Most systems utilize pneumatics or hydraulics to inflate elastomeric chambers, causing fingers to curl. This allows for lightweight end-effectors ideal for mobile robots.
Material Science
Constructed from silicones, polymers, and technical fabrics. These materials are inherently food-safe, non-conductive, and resistant to corrosion.
Universal Grasping
One gripper can handle a lightbulb, a bag of flour, and a metal pipe without changing tools. This versatility is critical for mixed-SKU logistics.
Product Safety
The inherent softness distributes force evenly across the contact surface, virtually eliminating damage to fragile goods during high-speed pick operations.
Energy Efficiency
Many soft grippers function on a "normally closed" or "jamming" principle, requiring energy only to change state, not to maintain the grip.
How It Works
Soft robotic grippers represent a departure from traditional "hard" robotics which rely on precise kinematic chains and rigid links. Instead, they leverage continuum mechanics . When pressurized air is introduced into the internal channels of the elastomer fingers, the asymmetry of the material's expansion causes the finger to bend.
This is often achieved through PneuNets (Pneumatic Networks) . The inner layer of the finger is inextensible, while the outer layer is flexible. As pressure builds, the finger curls inward, wrapping around the object.
For AGVs carrying mobile manipulators, this reduces the computational overhead. The robot doesn't need a perfect 3D model of the object; it simply needs to be close enough. The gripper's material properties handle the fine adjustments, acting as a hardware-level error dampener.
Real-World Applications
E-Commerce & Logistics
Picking varying item shapes from bins ("bin picking"). Soft grippers allow AGVs to pick a lipstick tube immediately followed by a plush toy without tool changes, increasing throughput by 40%.
Food Processing
Handling raw ingredients like dough, meat, or produce. The grippers are food-safe, easily washable, and do not bruise delicate organic items like berries or tomatoes.
Advanced Manufacturing
Moving polished or glass components. Soft silicone eliminates surface scratches that traditional metal grippers might cause, reducing scrap rates in electronics assembly.
Laboratory Automation
Manipulation of test tubes, petri dishes, and delicate glassware. AGVs can transport samples between stations with a secure yet gentle grip that accounts for wet or slippery surfaces.
Frequently Asked Questions
What is the payload capacity of a standard soft gripper?
While generally lower than rigid grippers, modern industrial soft grippers can handle payloads ranging from 2kg to 10kg depending on the design. For heavy-duty logistics, hybrid soft-rigid designs are often used to combine lifting power with compliant grasping.
How durable are the silicone fingers in an industrial environment?
Industrial-grade soft grippers are rated for millions of cycles. However, they are susceptible to cuts from sharp objects (like broken glass or sheet metal). In standard warehouse packing or food handling, they typically last 6-12 months before requiring simple modular replacement.
Do soft grippers require a compressed air supply on the AGV?
Yes, usually. However, they do not require large industrial compressors. Most mobile manipulators integrate small, onboard mini-compressors or electric vacuum pumps (24V) directly powered by the AGV's battery, keeping the form factor compact.
Can soft grippers handle wet or oily objects?
Absolutely. This is a primary advantage. The friction coefficient of silicone combined with the "form closure" (wrapping around the object) makes them superior to metal grippers for handling slick items in food processing or machining coolant environments.
How does the picking speed compare to vacuum suction cups?
Vacuum cups are generally faster for flat, uniform boxes. Soft grippers are slightly slower (actuation time 0.5s - 1.0s) but are infinitely more reliable for irregular items where a vacuum seal cannot be achieved, reducing the overall "retry" rate in the workflow.
Do I need force-torque sensors to prevent crushing items?
Generally, no. The pressure regulator sets the maximum force. Once the gripper is inflated to that pressure, it physically cannot exert more force, making it inherently safe for handling eggs or glass bulbs without complex sensor feedback loops.
Are they compatible with standard robot arms (UR, Fanuc, Kuka)?
Yes. Most commercial soft grippers come with ISO-standard mounting flanges and communication protocols (Digital I/O, Modbus, or IO-Link) making them plug-and-play with major collaborative robot (cobot) and industrial arm brands.
Can a soft gripper pick up a flat object like a coin or card?
This is a challenge for finger-based soft grippers. To address this, many designs incorporate a "fingernail" feature or combine the soft grip with a central vacuum suction cup to handle flat objects that cannot be wrapped around.
How does temperature affect performance?
Standard silicone grippers function well between -10°C and 80°C. For extreme environments (freezers or ovens), specific elastomer formulations are required to prevent the material from becoming too brittle or too soft.
What is "Granular Jamming" in soft robotics?
Granular jamming is a technique where a soft bag filled with grounds (like coffee or beads) is pressed onto an object. When air is vacuumed out, the particles jam together, causing the bag to become rigid and lock around the object's shape. It is excellent for heavy, odd-shaped items.