Throughout history, there have been industrial applications that require a load or force measurement within a system that involves either linear electric or hydraulic smart actuators. To accomplish the load measurement in these applications involved one of two main solutions: hydraulic smart actuators and electric smart actuators.
An open loop measurement system has been used by controlling the voltage and current sent to the actuator rotational servo motor. This method of force value calculation can have error percentages over 15-20%. Errors can occur due to both friction and the condition of the actuator.
Various industries are increasingly requiring much more precise measurement of load and force within their actuator systems. This can be accomplished using a strain gauge based load cell method of force measurement creating a Smart Linear Actuator. Placement of strain gauge based load cells either externally or internally within the actuator can provide precise force measurements within an accuracy of under +/- 1%. Rugged load cells can measure the force an actuator applies within the system or an external force acting upon the system. Various load cell outputs of mv/V, 4-20mA, 0-5VDC, J1939 CANbus, etc. send a signal that then allows the increase of power to the electric actuator servo motor or the hydraulic valve to properly adjust to the required level of force.
This article can also be seen featured on manufacturingtomorrow.com.