Mechanics of Motion Control Systems

With advancements in the programmable logic technologies, microprocessors, software, and power semiconductors, motion control software designers are capable of achieving more sophisticated, accurate, and reliable results. However, in order to capitalize on these software attributes, designers must choose the ideal motion control software, system technologies and components from the growing range of products and suppliers.

Making such decisions entails choosing high quality motion control system components such as; motor drives, motors, feedback sensors, and controllers and determining how they will operate together effectively. Mechanical motion control system factors determine their electronic design. Notably, human operator requirements, maintenance issues, product flow and throughput determine system mechanics that set the software and electronic requirements. An important part of the design process is to understand the mechanics of the motion systems and how they move and respond when installed on a machine. There are several options.

Mechanical actuators

Mechanical actuators main purpose is to offer a mode of converting the motion of a motor rotary into linear motion. Though some mechanical actuators have backlash, they all have finite axial and torsional stiffness levels that affect system frequency response features directly. Mechanical actuator options entails; ball screws, lead screws, rack and pinion, belt, chain or cable drives.

Linear bearings and linear guides

Linear bearings maintain a translating load that is constrained to a single freedom degree. If features technologies such as recirculating and non-recirculating rolling elements, profile shaped and round guides, hydrostatic, air and magnetic bearings as well as sliding type guides. Crucial linear bearings and guide attributes include; straightness, load capacity, smoothness, static friction, dynamic friction, rigidity, installation mounting surface preparation, and flatness.

Machine structure

Machine structure affects a motion control system in complex ways. Meaning that, a well-designed machine structure reduces the injection requirements of external disturbances through incorporating a compliant and highly damped barrier that isolates a motion control system from its surrounding environment while still maintaining a sufficiently damped and stiff structure without resonance problems. Note that, a highly static mass to reciprocating mass ratio bars motion controls systems from exciting structures they are attached to.

Other important components

Other motion control system mechanical components include; way covers that protect them against dirt and cable carriers for retaining moving cables, shock absorbers for dissipating energy when a crash occurs, and end stops for restricting travels. Note that, any movable mechanical component impact motion control system response by altering the resonance, stiffness, inertia, friction, and damping amounts.

Summary

Motion control software and systems are responsible for the motion path planning computational requirements, sequence execution, and servo loop closure. As such, a motion control software dedicated computer is programmed to execute predetermined tasks. However, motion control system designer must consider unique application requirements and mechanical components required.