Actuation & Speed reducers Flashcards
1
Q
What is an actuator?
A
Is a device used to cause something to happen. In an industrial robot it is used for moving the arm(s), the wrist(s) and the end-effector(s).
2
Q
Types (examples) of drives/actuators.
A
- Pneumatic motor
- Hydraulic / Oleodynamic motor
- Brushless motor
- Ball screw actuator
- Linear actuator
- Direct drive linear actuator
3
Q
All methods for speed reduction.
A
- Ordinary gears
- Harmonic drives
- Planetary gears
- Cycloidal reducers
4
Q
Ordinary gears for speed reduction.
A
- Stage of reduction (each with Wout = n*Win): n is the coeff. of reduction
- At the end we have Wout = n^s*Win
where s = # of stages
5
Q
Harmonic drives for speed reduction.
A
- Wave generator
- Flexible spline (hits the frame)
- Circular spline (frame)
n = (Zflex - Zcircular) / Zflex
where:
- Z = # teeth
- n = coeff. of reduction
6
Q
What are the encoders?
A
Are sensible devices that provide absolute positions or position changes.
They convert motion into electric signals.
7
Q
Difference between incremental and absolute encoders.
A
- ABS: mantains position informations when turned off
- Incremental: just provides position changes
8
Q
Pneumatic motor.
A
- Piston inside of a hollow cylinder (external compressor)
- Linear motion
- Very low precision
9
Q
Hydraulic / Oleodynamic motor.
A
- Incrompressible liquid
- Linear motion
- Good precision
10
Q
Brushless motor.
A
- Electric motor
- Revolute motion
- Very high precision
11
Q
Ball screw.
A
- Screw inside a cylinder
- Revolute to linear motion
- Low precision (?)
