Friday, October 06, 2006
The Planar Drive: a new concept in linear drives
ACP and D have recently launched the Cobra range of linear stepping motors which incorporate pneumatics and does away with the need for belts, screws or linear bearings.
A radical new design of linear slide looks like it will transform the market for precision XYZ movement control. ACP and D have recently launched the Cobra range of linear stepping motors which incorporate pneumatics and does away with the need for belts, screws or linear bearings. In this innovative design the stepping motor coils and magnets are fitted into the carriage.
The beam (which is also referred to as the stator) along which the carriage floats (just 15 microns off the surface) is simply a length of steel or stainless steel with notches cut into it.
The notches are filled with a polymer in order to make the beam surface smooth.
As the carriage 'floats' on a bed of air the only friction in the system is due to 'cable drag'.
The strong magnetic field keeps the carriage in place at all times and should there be a pneumatic failure the carriage immediately comes into contact with the stainless steel stator and is held in position by the magnetic forces due to the permanent magnets and magnetic field which the coils generate.
With the Cobra system vertical movement is also possible.
Use of stepping motors on linear slides (especially with long stroke lengths) has been held back in the past due to technical limitations such as the inertia of the lead screw or belt wear and often more complex and expensive servo motor systems have been used in their place.
Stepping motors have traditionally been used for light slow moving loads.
With the Cobra linear stepping motor system these are limitations of the past.
Use of pneumatics has ensured that higher maximum velocities up to 3m/sec can be achieved.
When used in combination with ACP and D's Star2000 range of low-cost stepping motor controllers the Cobra can provide step increments down to 10 microns with all the accuracy and repeatability and simplicity of a stepping motor system.
It is possible to build two stepping motors into a single carriage thus making an XY system which 'floats' over a stainless steel sheet instead of a beam.
This Cobra unit is known as a 'Planar Drive' and is pictured here.
Presently the maximum working envelope for the planar drive is 1800mm x 1800mm however it is expected that these dimensions will be increased over the next twelve months.
If required it is possible to undertake linear and circular interpolation movements using ACP and D's low-cost Goya 100 PLC in combination with the Star2000.
Another important feature of the Cobra is that (dependant upon available space) it is possible to have more than one carriage operating on the system at once.
On the linear stepping motor a number of carriages can be operated together or independently on the same beam or stator.
This is also the case for the planar drive.
If a number of robotic functions are required on a production line this important capability may well enable the total size on the line to be reduced with the obvious savings in cost and space.
Finally, prices for the linear Cobra system are extremely competitive and start at £650 for the carriage, steel beam and electronic Star2000 stepping motor controller.
A radical new design of linear slide looks like it will transform the market for precision XYZ movement control. ACP and D have recently launched the Cobra range of linear stepping motors which incorporate pneumatics and does away with the need for belts, screws or linear bearings. In this innovative design the stepping motor coils and magnets are fitted into the carriage.
The beam (which is also referred to as the stator) along which the carriage floats (just 15 microns off the surface) is simply a length of steel or stainless steel with notches cut into it.
The notches are filled with a polymer in order to make the beam surface smooth.
As the carriage 'floats' on a bed of air the only friction in the system is due to 'cable drag'.
The strong magnetic field keeps the carriage in place at all times and should there be a pneumatic failure the carriage immediately comes into contact with the stainless steel stator and is held in position by the magnetic forces due to the permanent magnets and magnetic field which the coils generate.
With the Cobra system vertical movement is also possible.
Use of stepping motors on linear slides (especially with long stroke lengths) has been held back in the past due to technical limitations such as the inertia of the lead screw or belt wear and often more complex and expensive servo motor systems have been used in their place.
Stepping motors have traditionally been used for light slow moving loads.
With the Cobra linear stepping motor system these are limitations of the past.
Use of pneumatics has ensured that higher maximum velocities up to 3m/sec can be achieved.
When used in combination with ACP and D's Star2000 range of low-cost stepping motor controllers the Cobra can provide step increments down to 10 microns with all the accuracy and repeatability and simplicity of a stepping motor system.
It is possible to build two stepping motors into a single carriage thus making an XY system which 'floats' over a stainless steel sheet instead of a beam.
This Cobra unit is known as a 'Planar Drive' and is pictured here.
Presently the maximum working envelope for the planar drive is 1800mm x 1800mm however it is expected that these dimensions will be increased over the next twelve months.
If required it is possible to undertake linear and circular interpolation movements using ACP and D's low-cost Goya 100 PLC in combination with the Star2000.
Another important feature of the Cobra is that (dependant upon available space) it is possible to have more than one carriage operating on the system at once.
On the linear stepping motor a number of carriages can be operated together or independently on the same beam or stator.
This is also the case for the planar drive.
If a number of robotic functions are required on a production line this important capability may well enable the total size on the line to be reduced with the obvious savings in cost and space.
Finally, prices for the linear Cobra system are extremely competitive and start at £650 for the carriage, steel beam and electronic Star2000 stepping motor controller.
# posted by Medical Information : 2:54 AM
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