Gripping and Clamping Applications With the KLA Linear Actuator
High Clamping Force and Precise Control of Gripper Fingers
The Kinitics Linear Actuator (KLA) is a shape memory alloy-based actuator that uses Bundled Wire technology to deliver high force and precision in a compact package. In a gripping or clamping application, the KLA can provide many unique advantages over other actuator technologies. Forces up to 2,000N can be generated and maintained within sub-Newton accuracy while strokes up to 8mm can be held to within 5 μm.
The KLA can be configured to work with industry standard AC or DC power sources, thus eliminating the need for pneumatic or hydraulic infrastructure. Holding current requirements are a small fraction of the actuator’s full-rated current. Additionally the KLA’s rated force can be maintained over long hold periods and is not subject to duty-based derating. A unique aspect of the KLA is that its return stroke follows a natural decay curve. Because of this behavior the actuator can tolerate brief power interruptions to maintain clamping force on the work piece.
From an electrical perspective the KLA behaves as a purely resistive device. The actuator has a broad linear region over its rated stroke length where its position is linearly proportional to power input. See Figure 1: Positional response under steady-state power.
Complex Control Made Easy
When operated in its linear region the actuator responds to modulating power in a smooth and highly predictable manner. Because the actuator acts as a resistive load, complex communication or control techniques are generally not needed in a gripping or clamping application; in most cases a simple PI control loop can be applied. Precise position control is possible through the addition of a linear sensor. Position control is also possible by monitoring the actuator’s impedance and applying it inside of a feedback loop. Extremely fine force control is possible through the use of a strain gauge permitting the application of clamping forces inside upper and lower limits as dictated by the end user.
The KLA can be easily configured with a rod that provides a pushing or pulling force, enabling outside and inside gripping and clamping applications. A through-rod can even be supplied for special arrangements. The KLA develops motion and generates force in a purely linear way, permitting its use in rigid assemblies that can effectively minimize mechanical backlash and slop. With no rotary elements present, wear surfaces can typically be reduced down to one linear rod bearing, or bushing, to handle side loading. By maintaining forces and strokes within their rated limits the actuator can provide millions of maintenance-free cycles.
For more information on using the KLA Linear Actuator for gripping or clamping, or help with your specific application, please contact us.
Linkage Style Gripper – Concept Arrangement
KLA05 Linear Actuator in ISO frame with through-rod.
Figure 1: Positional response under steady-state power