Load Cells are The Force Multiplier in Precision Gripping Applications
The seemingly intuitive act of grasping an object belies a complex interplay of forces that, when imprecisely measured, can lead to catastrophic failures and significant safety hazards across countless industrial and medical applications.
From the delicate touch required to manipulate a fragile semiconductor to the immense force needed to secure a heavy construction beam, accurate quantification of gripping pressures and end-effector-generated forces is not merely beneficial, but an absolute engineering imperative. The consequences of inadequate force measurement extend beyond mere inefficiency, encompassing crushing statistics related to material damage, operational downtime, and, most critically, can lead to safety issues.
Interface load cells have diverse capacities and capabilities foundational to enhancing gripping solutions across many industries. Force measurement sensor technologies provide real-time, reliable feedback on the gripping force exerted, enabling sophisticated closed-loop control systems. This level of precise measurement is critical for preventing damage to handled objects by ensuring the application of optimal force, validating ergonomic designs by quantifying user interaction forces, and ensuring operational safety by preventing over-stressing of components or inadvertent drops.
The test and measurement requirements for gripping applications are stringent. They demand high accuracy, repeatability, low hysteresis, and robust resilience to guarantee reliable performance in dynamic and varied operational environments.
Gripping Applications for Measurement Sensors
Load cells, particularly our Mini Load Cells and Load Button Load Cells, are often integrated into various gripping applications, from surgical robotics to drone lifting mechanisms. Additional industry solutions include industrial robotics, fixturing and clamps, medical devices, horticulture equipment, and general quality testing. The following highlights these types of gripping use cases.
Robotic End-of-Arm Tooling (EOAT)
In automated manufacturing and material handling, load cells mounted on robot grippers measure the force applied to parts during pick-and-place operations, assembly, and packaging. This prevents over-clamping, which could damage delicate components, and ensures a secure grip for safe transfer. For example, a low-capacity load button load cell in electronics assembly might precisely grip small circuit boards without causing fractures.
Industrial Clamps and Fixtures
It is common for miniature load cells to be incorporated into clamping mechanisms to monitor and control the holding force in machining, welding, and assembly processes. This ensures consistent part fixturing and prevents slippage or deformation due to excessive force. For instance, a high-capacity compression load cell within a vise in a CNC machining center can provide feedback to maintain the optimal clamping pressure on a workpiece.
Medical and Surgical Tools
Load cells are increasingly integrated into handheld surgical instruments and robotic surgery systems. Handheld tools like laparoscopic graspers provide surgeons with tactile feedback on the force applied to tissues, enabling delicate manipulation and preventing iatrogenic injury. In surgical robots, load cells on the robotic arms and end-effectors offer precise force control during procedures like tissue retraction, suturing, and organ manipulation, enhancing accuracy and minimizing trauma. Miniature S-type or button load cells are often employed in these applications due to space constraints and the need for high sensitivity. Review our application note: Robotic Surgery Force Feedback
Prosthetic Devices
In prosthetic hands and medical gripping tools, load cells provide sensory feedback to the user or operator, allowing for delicate manipulation and controlled force application. This is critical for tasks ranging from holding fragile instruments during surgery to enabling a prosthetic hand to grasp objects with appropriate pressure. Miniature S-type load cells are often used in such applications due to their compact size and ability to measure tension and compression. In this demonstration, you can see how using our BX8 instruction and 6-Axis multi-axis sensor, you can read the articulation forces during movement and gripping actions in real-time.
Drones and Unmanned Aerial Vehicles (UAVs)
As drones and UAVs become more sophisticated in their applications, including delivery, inspection, and potential human transport, load cells are crucial in their gripping and payload management systems. They ensure secure attachment and controlled release of payloads and can also provide feedback on the weight distribution and stability of the carried load, enhancing flight safety and operational efficiency. These weight-sensitive applications often prefer compact, lightweight load cells. Check out our solutions for testing commercial drones and parcel delivery.
Testing and Quality Control
Load cells are essential in testing various products’ grip strength and durability, from hand tools to consumer goods. They provide quantifiable data on the force required to grip and the maximum force the grip can withstand before failure. Universal load cells measuring tension and compression are well-suited for these testing scenarios.
Agriculture Systems
In automated harvesting systems, load cells on robotic grippers can detect the ripeness and fragility of fruits and vegetables, applying the precise force needed for a secure yet gentle grip, minimizing damage during harvesting.
Six Gripping Benefits of Utilizing Interface Sensor Technologies
Integrating Interface products into gripping equipment, products, machines, tools, and robotics offers several key benefits:
#1 Precise Force Control—Real-time force feedback enables accurate control of gripping pressure, preventing damage to handled objects and ensuring secure handling.
#2 Enhanced Safety—Monitoring grip force can prevent slippage of heavy or awkward items, reducing the risk of accidents and injuries. In medical applications, it minimizes the risk of tissue damage during procedures. In drone applications, it ensures secure payload attachment during flight.
#3 Improved Efficiency—Optimized gripping force can lead to faster cycle times in automated processes and reduced material waste. In surgical robotics, it can contribute to more efficient and less invasive procedures.
#5 Quality Assurance—Consistent and controlled gripping forces in manufacturing and assembly contribute to higher product quality and fewer defects. In medical device testing, they also ensure the reliability and safety of surgical tools.
#6 Data and Traceability—Load cell data can be recorded and analyzed for process optimization, quality control, and predictive maintenance. It can provide valuable data for training and procedure analysis in surgical settings and contribute to better payload management strategies in drone operations.
Interface Products Used for Gripping Test and Measurement Use Cases
Interface offers a wide array of load cells suitable for various gripping applications, including:
- LowProfile Load Cells: These are compact and versatile, ideal for applications with limited space. They offer both tension and compression measurement capabilities. Examples include the 1200 and 1500 series, often used in drone payload systems.
- Miniature Load Cells and Load Button Load Cells: These small, high-sensitivity sensors are perfect for integrating compact grippers and precisely measuring force in tight spaces. They are commonly found in surgical instruments and more miniature robotic grippers. The ConvexBT™ Load Button Load Cell is designed to improve off-axis resistance.
- S-Type Load Cells: These cells are designed to be highly accurate for tension and compression measurements. They are often used in gripping mechanisms and testing applications, and can be adapted for larger robotic surgery arms. The SSMF Fatigue Rated S-Type Load Cell is suitable for durability testing.
- Beam Load Cells: These robust sensors are ideal for higher-capacity gripping applications and can be integrated into clamping fixtures. Examples include sealed S-Beam Load Cells for demanding environments.
- Multi-Axis Load Cells: These cells can simultaneously measure forces in multiple directions, providing comprehensive data for complex gripping tasks, such as advanced robotic surgery and sophisticated drone manipulation. The 6A series measures force and torque in all six axes.
- Load Washers: These are designed to measure bolt clamping force. They are helpful in applications where secure fastening is critical for the gripping mechanism, including ensuring the stability of drone components or surgical robot joints. The LW series is used to measure bolt tension.
Engineers can develop highly effective and reliable gripping solutions for various industrial, medical, aerospace, drone, and research applications by selecting the appropriate Interface load cell based on capacity, size constraints, environmental conditions, and measurement requirements.
