Posted to News on 23rd Jan 2009, 14:56
ERMB rotary actuators are cost-effective and versatile
Festo is launching a series of electromechanical rotary actuators that provides an excellent level of versatility. Capable of accommodating any desired angle of rotation - including a full 360deg and continuous unlimited rotary motion - the ERMB modules are said to set a new standard in rotary positioning performance. The modules feature mounting interfaces on each of their six sides and can be mounted in any position, making them easy to integrate with other axes. They also have a large-diameter hollow output shaft to facilitate the feed-through of cables and tubing. They are particularly suitable for orienting gripper units at the front end of cantilever axes, and also provide a simple low-cost means of implementing high-speed rotary positioning tables.
Festo offers three sizes of ERMB rotary modules, with maximum output torques of 3.1, 8.8 and 24Nm. The ERMB-20 measures 65 x 145mm, with a height of 54mm and weighs 850g. Despite its small form factor, the actuator can handle direct loads of up to 30kg and moments of inertia as high as 200kgcm/cm. As for the ERMB-32, it can accommodate moments of inertia as high as 3700kgcm/cm.
ERMB series rotary modules use a pretensioned toothed belt to transfer power from the motor shaft to the output pinion, resulting in smooth, low-noise operation with minimal backlash. All three models can achieve an angular velocity in excess of 30rad/s - which translates into a 180deg positioning time of less than 0.2s - with a repetition accuracy of +/-0.03deg.
Position sensing options
All ERMB series rotary modules feature a built-in homing sensor for use when indexing, and they can also be equipped with an optional sensing kit for monitoring angular displacement. The sensing kit is available with or without a protective housing to suit the application, and can be mounted on either side of the rotary module. It uses two sets of easily adjustable cams in conjunction with a pair of magnetic proximity sensors to provide digital feedback to the system controller, and offers a versatile means of implementing blocking or 'anti-crash' motion control sequences.
Festo's ERMB rotary modules are mechanically compatible with the company's range of electric and pneumatic products such as linear positioning axes and grippers, and are suitable for use with a wide range of stepper and servomotors including third-party products.
When teamed with Festo's MTR-DCI intelligent servomotors, the ERMB rotary modules provide a complete, all-in-one programmable rotary positioning system. These innovative motors incorporate gearing, together with an optical encoder and all necessary controller and power electronics, in a single, compact package, and even offer a built-in LCD option that enables the axis to be commissioned at the point of use, if required. MTR-DCI servomotors can be controlled via a variety of fieldbuses including CANopen, Profibus DP and DeviceNet and the built-in controller is capable of storing 16 motion control programs in non-volatile memory including acceleration and velocity profiles for rotational movement.
Customers can specify a rotary actuator, mounting interfaces and motor/drive combination in a single part number, to help reduce administration time and cost.
For more information go to www.festo.com/cms/en-gb_gb/2358.htm.
