Micropositioning meets Mechatronics
This goniometer includes an actuator with integral motor. Height and performance requirements called for a low profile direct-drive motor system, which meant embedding a custom linear motor directly into the stage base. Compared to traditional methods, the mechatronic design approach is more of a holistic approach to product design, where the tradeoffs between different functional components (software, hardware, user interface, etc.) are carefully considered for their impact on overall performance. The goal of the process is to arrive at an optimal solution at the conclusion of product design. Mechatronic principles have been successfully deployed in numerous applications such as hard drives, robotic manipulators, temperature control, and automotive systems. Here we consider mechatronics in micropositioning stages....
Minimizing vibration
Vibrations stem from a behavior that's inherent to all mechanical structures. Under load, all structures slightly deform and act springlike, causing motion to ripple to and fro as energy waffles between kinetic and potential. Vibrations are as complex as these structures they run through, and are an intricate composite of movement, especially rotating motion, where both amplitude and frequency change dynamically with cycling deformations caused by misalignment, play, and impact forces. ...
Feedback for servos
Servomotor-powered motioncontrol systems are expected to be fast, accurate, and reliable. Yet even the most expensive servomotors can be victims of external factors degrading their performance. Leading the list is the feedback device sending position and other information back to the motor controller...
Muscles, not motors
In the last 20 years or so, researchers have developed several classes of electroactive polymers— plastics that can change shape when one applies a charge to them. Because this mechanism resembles an animal's muscle, that's what actuators based on this technology are often called. Electroactive polymer artificial muscles (EPAMs) consist of a thin layer of polymer film between two compliant electrodes. ...
Cutting curves, not corners
Highly automated sawmills are the norm in today's lumber industry. Modern lines debark, trim, cut, and saw up to 20 logs/min — depending on the type and size — with tolerances in the tenths of millimeters...
Correcting errors that never happen
For many years the standard means of controlling servoloops on motion controllers (or other devices) has been the PID loop. Back in the days of analog control the motion controller was typically a CNC device responsible for closing the proportional-gain (P) loop and, if used, the steady-state or integral gain ( I ) loop...
Operation: Shrink labeling
Labeling products is a mass-production proposition, but its complexity is only growing with increasingly diverse products in convenience, travel, and wholesale-club formats. It begins with wrapping (printed with names, company logos, and other information) that's pulled or stretched over product — whether containers of several items, or individual units such as juice, soap, or bleach bottles. Then, with shrink-wrap labeling, heat makes labels tighten onto the products. ...
Coming to grips with compliance
Q. The single issue that causes the most discussion during our motor-sizing process is compliance and stiffness. Is there a typical way of allowing for compliance? ...
Optical scanning: the Ferrari of motion control
Optical scanning can rightfully be termed the Ferrari of motion control applications because the required speed and accuracy is typically an order of magnitude or two faster than conventional motion control systems. Optical scanners control the movement of a mirror, which in turn steers a laser beam for applications such as marking characters on everything from medical products to packaged food....
Close scrutiny for thin films thanks to innovative encoders
New metrology equipment can resolve distances down to 19 nm on semiconductor wafers through use of positioning gear that incorporates special optical encoders...
Choose wisely
Brushed and brushless servo-motors are found in many diverse areas including medical, industrial, home, aerospace, defense, and robotic fields. And each application potentially requires a different motor...
Pick-and-place operations
Servo technology makes pick-and-place operations faster and more precise; integrated motion and modular programming simplify their design....
Avoiding the runaround with direct-drive rotary motion
Direct-drive rotary (DDR) systems are available in frameless, housed, and the newly developed cartridge motor format. Although many engineers are familiar with the basics of selecting conventional servo systems, the rules are a bit different when selecting a DDR system...
Asynchronous Control
The 940 PositionServo is a digital servodrive with a robust motion controller that is compatible with G-motion asynchronous gearmotors...
Pneumatic actuation basics
Pneumatic actuation plays a major role in today's world of computerized automation. It's reliable, economical, and surprisingly easy to use. Understanding pneumatics is a matter of physics. When air inside a container builds up, pressure magnitude is the same at all points within the fluid. The air also pushes out on its vessel uniformly....
