Motion Control

Achieving Positioning Accuracy Goals

The task of choosing the correct mix of motion control components for a successful servo positioning system involves a combination of art, science, and experience. It also includes a little luck, but luck is not needed when you fully comprehend the principle of operation, accuracy, resolution, and repeatability of each component in the system.

Posted in: Articles, Motion Control, Stability control, Flight control actuators, Flight control actuators, Parts, Spacecraft

Alternatives to Keyways in Motion Systems

The age-old tradition of using shaft keys in mechanical drives has served the power transmission industry well for many years. When appropriately sized, it guarantees that virtually no relative motion can take place between a shaft and its respective shaft hub in a unidirectional continuous motion application. Today’s increasing demands for speed, precision, and small size have changed the standard for shaft locking devices, and challenged motion components manufacturers to develop new methods of keyless shaft locking for dynamic loading. As motors and drives become increasingly capable of rapid acceleration and rotary positioning accuracy in smaller and smaller packages, backlash, stress distribution, and balance have all needed to be addressed in shaft locking devices, in many cases rendering the shaft key obsolete.

Posted in: Articles, Motion Control, Fittings, Parts, Driveshafts, Transmission gears

QC Lasers Improve Hazardous Gas Monitoring

The measurement of gases associated with industrial processing/emissions monitoring has become increasingly important as the need to improve efficiencies in process control has increased, and legislation governing emissions has come into force. Gases including NOx, SOx, CO2, CO, NH3, and H2O commonly are used to assess processes such as combustion and quenching, while many fall under emissions legislation resulting from the Kyoto agreement.

Posted in: Features, ptb catchall, Articles, Motion Control, Photonics, Lasers, Lasers, Emissions measurement, Gases

AC Drives Provide Precise Control Critical to Next-Generation Test Stands

Direct Torque Control (DTC) is widely used as a method for controlling AC motors in many demanding applications. It is a unique method for controlling AC motors. In pulse-width modulation (PWM) drives, the output frequency and voltage are the primary control reference signals for the power switches, rather than the desired torque in/of the motor shaft. For those who are not familiar with inverter technology, the DTC principle can be illustrated most accurately via this mechanical analogy: the continuous calculation of the best angle at which to rotate a shaft, with a given arm length and the forces available. These electrical “force vectors” are generated with the help of semiconductor switches called Integrated Gate Bipolar Transistors (IGBT).

Posted in: Articles, Motion Control, Switches, Switches, Driveshafts, Electric drives, Torque converters, Test equipment and instrumentation

The Air Bearing Advantage in High-Precision Positioning

All moving objects possess six degrees of freedom — three linear and three rotary. The task of a linear motion guideway is to eliminate, as closely as possible, five of these degrees of freedom, leaving a single rotary or linear axis of motion. Air bearings are the purest and highest-performance means of defining linear or rotary motion, and have substantial advantages over conventional mechanical guideways. These advantages become more pronounced as the desired resolution increases, and many aspects of high-precision positioning are uniquely enhanced when air bearing guideways are chosen.

Posted in: Articles, Motion Control, Bearings

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