Long Stroke Actuator with High Resolution Positioning
Linear ActuatorLinear MotorLinear StageLinear MotionElectro-mechanical actuatorLinear Stepper MotorPiezoelectric Linear Stage
The presented motor is a linear stepping motor so called Fine Stepping Piezo Actuator (FSPA) able to support large external force without losing its holding position whether powered or unpowered. FSPA are based on inertial stepper piezo motors. They are composed of four main elements: an actuator, a lever arm, a mass and a clamp. The principle of such motors is simple and relies on stick-slip effect and dissymmetrical accelerations. The Fig 1 shows the two phases needed to produce one step. First, a slow contraction of the actuator makes the mass moving, without any motion of the shaft, because of clamping friction. Then, a fast actuator expansion gives dynamic forces to mass and shaft and, because of the inertia of the mass, overcomes the friction forces. This moves the shaft into the clamp and one step is completed. By repeating this operation, stroke of several millimetres can be reached. The opposite motion is done by inversing the two sequences. This motion is called “Stepping Mode”.
HIGH RESOLUTION LINEAR CONFIGURATION
Proposed configuration is combining advantages of stepping mode, with a high resolution, irreversible, reduction mechanism. The internal structure allows decoupling high external forces from actuation mechanism. Therefore, it makes the motor compatible with high loads and high levels of vibration.