Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations JAE on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
servo motors
- Thread starter Flatbush
- Start date
Servo refers to a type of control "closed loop". There are also servo vavles and servo linear motors. The thing that makes a servo system is some type of positioning feedback device that will allow a servo controller to stop the motion at a set position or reverse and go back the a set position if it has over shot the set position. The cruise control in a car is a servo system which tries to maitain a set position (speed) while going up and down hills.
The feedback on a servo motor is usally a encoder or resolver which is attached to the back of the motor rotor and produces a number of pulses or sine waves per revolution of the motor. You then command the controller to rotate the motor x pulses, which it does then holds that position until told otherwise. The type of voltage waveform mostly used is a constant amplitude square wave that is modulated by the pulse width(PWM). The algorithm (formula) used by the contoller has 3 basic factors. Proportional Gain which causes increases power in proportion to the position error, Integral Gain which increases over time and Derivative Gain which acts as a damper.
Servo motors are very high preformance motors with a built in feedback device.
If you go to different servo mfg websites they will usally have more detailed info. Some of the mfgs are Baldor, Allen Bradley, Yaskawa, Sanyo-Denki, Baumuller, Kollmorgen and pacsi.
Hope this helps
Barry
The feedback on a servo motor is usally a encoder or resolver which is attached to the back of the motor rotor and produces a number of pulses or sine waves per revolution of the motor. You then command the controller to rotate the motor x pulses, which it does then holds that position until told otherwise. The type of voltage waveform mostly used is a constant amplitude square wave that is modulated by the pulse width(PWM). The algorithm (formula) used by the contoller has 3 basic factors. Proportional Gain which causes increases power in proportion to the position error, Integral Gain which increases over time and Derivative Gain which acts as a damper.
Servo motors are very high preformance motors with a built in feedback device.
If you go to different servo mfg websites they will usally have more detailed info. Some of the mfgs are Baldor, Allen Bradley, Yaskawa, Sanyo-Denki, Baumuller, Kollmorgen and pacsi.
Hope this helps
Barry
jbartos
Electrical
- Jan 15, 2000
- 6,440
Suggestion: Visit
for servo basics
for servo basics
jbartos
Electrical
- Jan 15, 2000
- 6,440
Suggestion: Visit
for PID and Servo
for PID and Servo
jbartos
Electrical
- Jan 15, 2000
- 6,440
Suggestion: Actually, the servo is covered wery well on Web. Also, it is a popular area to study at various educational levels. Visit
(for servo systems)
(for Robust Optimal Servo Controller)
etc. for more info
(for servo systems)
(for Robust Optimal Servo Controller)
etc. for more info
jbartos
Electrical
- Jan 15, 2000
- 6,440
Suggestion: Actually, the servo is covered wery well on Web. Also, it is a popular area to study at various educational levels. Visit
for servo basics
for PID and Servo
(for servo systems)
(for Robust Optimal Servo Controller)
etc. for more info
Servo hardware is available over
and type Servo Systems under Product or Service, which will return 139 companies to approach to
Alternately,
type Motors: Servo that will return 232 companies to approach to
and
type Drives: Servo that will return 146 companies to approach to
for servo basics
for PID and Servo
(for servo systems)
(for Robust Optimal Servo Controller)
etc. for more info
Servo hardware is available over
and type Servo Systems under Product or Service, which will return 139 companies to approach to
Alternately,
type Motors: Servo that will return 232 companies to approach to
and
type Drives: Servo that will return 146 companies to approach to
Plenty of useful stuff !! I have little experience with servo motors myself - I am currently trying to replace a 6-pole servo and having lots of fun, the motor insists on going in the wrong direction. I've re-programmed the controller to the best of my ability (it's in Italian!) with a simple direction command (MD=0 fwd MD=1 reverse) but it still goes the wrong way !!! AGggggghhhhh
analogkid2digitalman
Electrical
Dazmac-
Is it a brushed servo, if so make sure power polarity is correct. Also check polarity of +/-10 position command signal if applicable.
Is it a brushed servo, if so make sure power polarity is correct. Also check polarity of +/-10 position command signal if applicable.
On the servo going reverse, two things to check.
That the motor is compatable with the drive. Unless the feedback is clocked the way the drive expects it to be it won't work.
If this is an old DC servo with a tach it need to be the right polarity also.
Barry
That the motor is compatable with the drive. Unless the feedback is clocked the way the drive expects it to be it won't work.
If this is an old DC servo with a tach it need to be the right polarity also.
Barry
Thanks guys, spent 2 solid days on it (apart from stopping to talk to production managers who ask how it's going- why do they do that ?)
Furhter details, a brushless drive, resolver.
As I said, I found a command in the controller for direction (MD), then slept on it last night and went in this morning, looked again at the application code and jumping out at me was XR=0 -- Resolver direction ! changed this and hey presto!
Tried the drive and it ran 1/4 speed, spent all day messing with tweeks to the application before working out new resolver is 14-bit, the old one was 12-bit !
Changed resolver settings in initialisation routine and it runs like a dream!
Furhter details, a brushless drive, resolver.
As I said, I found a command in the controller for direction (MD), then slept on it last night and went in this morning, looked again at the application code and jumping out at me was XR=0 -- Resolver direction ! changed this and hey presto!
Tried the drive and it ran 1/4 speed, spent all day messing with tweeks to the application before working out new resolver is 14-bit, the old one was 12-bit !
Changed resolver settings in initialisation routine and it runs like a dream!
- Status
Similar threads
- Question
- Locked
- Question