Thursday, April 30, 2009

Industrial Mechatronics Drive Unit

The Industrial Mechatronics Drive Unit (IMDU) is part of the new Mechatronic Controls Collection line of Quanser experiments. The system is 17.8 cm high, 30.5 cm long, 30.5 cm wide, and weighs 12.9 kg and, as illustrated in the image below, it has four external shafts. Two shafts are actuated through a 3:1 belt drive system with a DC Motor while the other two are passive. The position of each shaft can be measured using the high-resolution encoders. The built-in 150 W linear current controlled amplifiers that drives the DC motors are capable of supplying up to 10.0 A. So there is no need for an external amplifier.

The IMDU is a reconfigurable system and is extremely versatile. It is supplied with two inertial loads, five pulleys of different sizes, two belts, a backlash unit, and a friction unit. The inertia loads have adjustable weights: up to four can be placed and the location of each can be changed. By mounting the various pulleys on the different shafts and using the belts, a multitude of experiments can be performed. The device itself is supplied with four experiments: DC Motor Position Control, DC Motor Speed Control, Disturbance Rejection, and Haptic Knob. The IMDU can be run on a PC with the QuaRC control software through Matlab/Simulink.

The friction and backlash units can be used to add these corresponding effects to an output shaft. This permits the user to study the effects of real backlash and friction – not simulated. This lends itself well to control engineers who want to test their friction and backlash compensation or identification schemes.

To add to the list of experiments that can be performed on this device, a Web Winding Transport Module and a Multi-DOF Torsion Module are available. The web winding module can be added to the base IMDU system to convert the plant into a paper machine simulation. In this configuration, the goal is to process the paper as fast as possible without tearing the product. This is done by adjusting the tension and the rate of the spindles.

With the torsion module, the output of the motorized shaft is connected to a flexible coupling that is then connected to an inertial load (as pictured below). The challenge is to control the position of the output shaft while compensating for the joint flexibilities introduced by the torsional member. This reenacts common issues found in the real world, e.g. high-gear ratio harmonic drives.

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