Publications
Categories
Stiff and soft stewart platforms for active damping and active isolation of vibrations
6 January 2002
As future astronomic missions will require more and more stringent resolution requirements, the high demand for an environment clean of vibrations and disturbance appears. This also leads to the need for high precision steering devices for fine pointing of sensitive optics with the highest possible accuracy. Several methods exist to reduce vibration levels: the first consists in isolating the sensitive system from the perturbation and the second in damping the structure vibration modes. Therefore, two Stewart platforms have been designed, manufactured and tested. The first is a soft hexapod that provides 6 degree-of-freedom (DOF) active isolation and the second is a stiff hexapod that provides active damping to whatever flexible payload attached/mounted to it. In addition, both hexapods have steering capabilities.
Amélioration des performances des actionneurs APA®
19 June 2023
Increase the dynamic mass energy density and reduce the effects of inertia by playing on materials and geometry.
Strain gages sensors for high stability piezo actuators
19 June 2023
Space, military, and industrial applications require precision position sensors in order to perform closed-loop control or to monitor the state of a system. Those applications usually come with constraints such as wide thermal range, long lifetime, high stability, and compactness.
Amplified Piezo Actuator APA® with viscoelastic material for machine tool semi active damping system
8 January 2016
Modern machine tools must achieve a high precision for a better surface texture and higher flexibility for wide range of machining requirements. To fulfill these requirements, a semi-active damping system for a new generation of machine tools is proposed. The new concept is partially based on the Amplified Piezo Actuators APA® from CEDRAT Technologies. With these actuators, the dynamic behavior (stiffness and damping) of structural body components of machine tools can be controlled and adjusted to the optimum parameters. To reduce the transfer of vibrations through the active elements, a viscoelastic material was used. This article presents test results performed on the APA® with viscoelastic material. A significant reduction of the vibrational amplitude at resonance frequency was observed with additional material. The optimized quantity of viscoelastic
material reduces the full stroke of the actuator only by 10 percent. At the same time, the viscoelastic material has reduced the amplitude at resonance frequency by more than double. The designed actuator obtains a blocking force of 8.5kN. Results obtained from the tests performed on the machine tool showed significant surface texture improvement with use of the amplified piezoelectric actuator.
Amplified piezo actuators enhancement for active vibration control
7 June 2018
Amplified Piezo Actuators (APA®) from CEDRAT TECHNOLOGIES are known to be compact and especially performing in dynamic applications. The recent evolutions realized on the APA® and drive electronics allow them to address active damping better than magnetic proof mass in terms of the Force to Volume ratio above some 10Hz. The dynamic capability of the APA® has been improved thanks to preload method enhancement. Research has successfully shown the possibility to achieve a high dynamic force level similar to the static blocked force of the piezo actuator. This technical progress coupled with an amplified motion makes possible the generation of high mechanical proof mass load at relatively low frequency. It produces a force higher than 100N in a volume of Ø40x75mm within a range of [100-300Hz]. This paper presents relevant uses of APA® for active damping in machining applications. Several machining case studies are reported integrating Amplified Piezo
Actuators within the spindle head, inside the cutting tool or beside the workpiece clamp.
Cryogenic piezo characterisation and integration For Fine Steering Tip/Tilt Mechanism
19 June 2023
High precision cryogenic applications are demanding domains that require precise knowledge of component performance. In the case of active components such as piezoelectric actuators, such knowledge includes stroke, capacitance and Coefficient of Thermal Expansion (CTE). These parameters are difficult to define with precision because of the combination of small displacements and low temperature sensor compatibilities. A high stability and low sensibility test bench is required to obtain such results
