olefud wrote:Tommy Cookers wrote:the electric or electromechanical actuator must have springing in parallel for it to control the dynamic response
so it will need to be rather capable in both force capacity and bandwidth
and can beyond its nominal bandwidth be allowed some managed 'free' backdriving ie on severe/high frequency bumps
in any parallel system there will be force differences ie some conflict (in this case between the actuator and the springs)
this happens in conventional suspension (that's what dampers do), and in the F1 Active
there's no easy way out, strut compliance must be manageable by the millisecond, this demands both power and bandwidth
a low-power electromechanical system will give mostly uncontrolled Newtonian damping
The voice coil has inherent, rate-progressive damping in that movement of the coil in the magnet gap generates current in the coil. Of course, as with hydraulic dampers, the energy would have to be sunk somewhere, perhaps as rectified current to a battery.
from experience I can say that any motor or actuator with a permanent field will resist backdriving from an external load
that resistance will small if the motor is in open circuit, much larger otherwise and so can easily be continuously varied
if the system ideally manages the resistance we have achieved what conventionally could be called ideal damping ?
but backdriving eg compression can be faster by open circuiting than the system being energised to drive itself in compression
uniquely servo motors/actuators have electromagnetic time constants much lower than even their electromechanical time constants
giving systems with eg a phase response eg suitable for retaining stability at very high forward path gain
necessary to be in the same capability ballpark as servo hydraulics
for various reasons other motors/actuators have larger armature inductance etc and high electromagnetic time constants
and so will be relatively poor at doing the job of their servo equivalents
