Piezo motors
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Force Stepping Piezo Actuator : a motorised solution for high resolution positioning and external forces resistance
19 June 2023
Typical holding force of piezo motors is defined by friction force, required to make motor move. However, increase of friction force is not inconsequent for motor performances in terms of speed, max motion force and lifetime (tribology). In this paper, a new motor, offering high resolution positioning and holding position when unpowered, is presented. Based on a Stepping Piezo Actuator [1] at its core, this new design decouples the outer forces from the most sensitive parts of the motor. This allows the motor to propose a high force/mass ratio and sustain even higher forces without supply. Results obtained on prototype are presented, giving the reader the benefits of proposed technology.
FSPA and BSMA Nanometric positioning actuators for ground and space applications
19 June 2023
Many applications and more specifically space projects show need for a stable sub-micrometre positioning actuator. In order to meet this need, Cedrat Technologies has designed the new FSPA brand. This linear stepping actuator offers sub-micrometric positioning resolution along 5mm stroke combined with high actuation force (>100N) and the ability to hold its position without power.
The IASI-NG instrument is one of the key payload on-board METOP-SG which is a new meteorological satellite for Europe. The instrument is based on a Mertz interferometer and requires a very precise positioning of an optical blade used to separate the interferometer’s branches. A dedicated version of the FSPA, the Beam Splitter Mechanisms Actuator (BSMA) is then developed to achieve this nanometric positioning which is a key parameter for the overall instrument performance.
This paper firsts present the internals of both FSPA and BSMA actuators. Major design differences and their respective impact on the resulting performances are detailed. Results from the acceptance and qualification test campaigns are also presented.
Design of a dynamic tribometer applied to piezo inertia drive motors
7 November 2019
In Inertia Drive Motors, generated motion is based on stick-slip principle. Current analytical models are predictive enough to calculate qualitatively their optimal performances, such as maximal step size and speed, with relatively few input parameters. Butn they do not take into account the contact life and temporal evolution of parameters as friction factor all along lifetime of IDM. So analytical models reach their limitswhen precise predictions are necessary.
Design of a dynamic tribometer applied to piezoelectric Inertia Drive Motors – In situ exploration of stick-slip principle
19 June 2023
In Inertia Drive Motors, generated motion is based on stick-slip principle. Current analytical models are predictive enough to calculate qualitatively their optimal performances, such as maximal step size and speed, with relatively few input parameters. But, they do not take into account the contact life and temporal evolution of parameters as friction factor all along lifetime of IDM. So, analytical models reach their limits when precise predictions are necessary. This investigation aims at understand wear mechanisms to model temporal evolution of friction. Such an understanding requires the reconstitution of the contact life through the evaluation of 1st and 3rd body flows. To do so, a new IDM-representative tribometer is designed. First bodies – coated TA6V and polymer – are not see-through. They are replaced alternatively by an intermediate transparent first body to observe the contact dynamically and in-situ. Friction factor, step size and mean speed are also measured. Preliminary results shows that wear profiles from real IDM and tribometer are similar. Direct observations bring out particles of TA6V coating are firstly snatched, then moves in contact and finally trigs others particle detachments.
Thermal vacuum behaviour of a stepping piezo actuator
19 June 2023
The presented work illustrates the design of a new high force Stepping Piezoelectric Actuator (SPA) and describes its Thermal Vacuum testing as performed by ESTL, in order to investigate SPA compatibility with vacuum environment within a wide temperatures range; from +60°C down to -180°C. A dedicated test bench was designed, in order to check motor force and speed for all performed tests. Instrumentation, testing and observations about tribological behaviour of friction interface have been realized by ESTL, showing interesting perspectives.
High power density Piezo motors for critical environments
8 September 2022
Piezoelectric motors offer many advantages for applications in numerous industrial sectors. The requirements for which these solutions are developed are focused on their main advantages such as non-magnetic and radiation compatibility, high force/volume ratio, good unpowered stall force and low power consumption. Such applications are typically concerned by exotic working conditions on which the piezoelectric motors still need to improve regarding the technological readiness level.
