D2.1 Requirements and Specification - CORBYS
D2.1 Requirements and Specification - CORBYS
D2.1 Requirements and Specification - CORBYS
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<strong>D2.1</strong> <strong>Requirements</strong> <strong>and</strong> <strong>Specification</strong><br />
motors.<br />
An example of a smart fluidic actuator is the Rotary Elastic Chambers – Actuator developed at IAT in<br />
Bremen. The modules comprise very few fully integrated components with matched mechanical <strong>and</strong><br />
electrical interfaces: fluidic vane motor, sensors, control elements, as well as an electronic unit <strong>and</strong> control<br />
algorithms.<br />
Figure 36: Rotary Elastic Chambers – Actuator (IAT<br />
Bremen)<br />
With integrated control unit<br />
144<br />
Figure 37: Flexible Fluidic actuator (AIA KIT, Karlsruhe)<br />
Shows the working principle of the vane motor<br />
Another fluidic actuator principle has been presented by Festo AG. The “fluidic muscle” provides a linear<br />
type of actuation, but does not include a control unit within the actuator.<br />
Other smart actuator solutions are mostly based on electromagnetic motors. The motor techniques used here<br />
are stepper motors, brushed DC motors <strong>and</strong> permanent magnet synchronous motors.<br />
Dimensioning an appropriate electromagnetic motor for a given application influences the choice of the motor<br />
technique. The most important criteria are housing size, weight, scalability, price, delivery st<strong>and</strong>ards but also<br />
costs resulting from motor control electronics <strong>and</strong> software. Depending on the motor choice the expenditure<br />
on drive control can be very different. Therefore some advantages <strong>and</strong> disadvantages of the named motors<br />
techniques are explained. It must be considered that smart actuators in most cases are also being used for<br />
measurement of actual data like position, speed, temperature <strong>and</strong> motor current.<br />
14.2.1 DC motor<br />
Until some years ago mechanically commutated DC motors had been used for highly dynamical servo drives.<br />
The negative features of this motor technique are based on the principle design where the rotating coil is<br />
centred inside the motor housing <strong>and</strong> heat is unable to dissipate appropriately. In addition the mechanical<br />
commutation limits the stall current but also the current at higher rotation speed because of brush fire. Low<br />
cost DC motors have limited life time because of brush wear. Brush fire can cause high frequency noise<br />
causing trouble in the power supply of other components connected.<br />
14.2.2 Stepper motor<br />
Stepper motors are an inexpensive alternative for small power drives (