A mechanical system has a component, which is movable under friction. An oscillating micromotion (dither) is impressed upon the component, which, if necessary, is added to a non-oscillating base motion of the component. It is provided that the micromotion (without the base motion that is additional, if necessary) is faster within a period of the oscillation in the one direction and is of shorter duration than in the opposite direction (asymmetrical dither).

Focus arrangements for laser radar and other applications provide compensation of orientation-dependent gravitational forces. A linear stage can be preloaded and provided with balanced linear encoders so that gravitational force induced pitch, yaw, and roll can be reduced, detected, or compensated. Alternatively, movable focus elements can be secured to actuator driven spring assemblies that are controlled to compensate orientation-dependent gravitational forces.

An improved actuator arrangement for operating a driven element with different actuators. The actuator arrangement comprises a first actuator that drives a driven element in a first direction via a first output member and a second actuator that drives the driven element in a second direction opposite to the first direction via a second output member. The first and second actuators are configured to work in a counter-acting manner to move the driven element in the first and second directions. An additional connecting and supporting device is connected between the first and second output members to support the output members to bear transversal forces transversal to the moving direction and/or to bear pre-load force for pre-loading the actuators.

A tilt assembly for a blind including a first tilt ring and a second tilt ring, both rotatable about a drive axis for supporting a pair of tilt ladders, an input connector rotatable about the drive axis and configured to receive a drive shaft for rotating a lift spool and the input connector, a secondary input mechanism rotatable about the drive axis and configured to receive the drive shaft for rotating the secondary input mechanism with the input connector, a main clutch mechanism for releasably connecting the first tilt ring to the input connector and configured to release connection at each of two opposite rotational orientations of the first tilt ring, and a secondary clutch mechanism for releasably connecting the second tilt ring to the secondary input mechanism and configured to release connection at each of two opposite rotational orientations of the second tilt ring.

Ratcheting shape memory alloy actuators and systems and methods including the same are disclosed herein. The ratcheting shape memory alloy actuators include a ratcheting assembly that is operatively coupled to a first bracket and a shape memory alloy element that is operatively coupled to the ratcheting assembly and to a second bracket. The first bracket is configured to be operatively coupled to a first structure, while the second bracket is configured to be operatively coupled to a second structure. The shape memory alloy element is configured to apply a motive force to the ratcheting assembly upon deformation between a first conformation and a second conformation. The ratcheting assembly is configured to utilize the motive force to selectively adjust an orientation of the first structure relative to the second structure.