Controller’s Improved Processing Power Speeds Trajectory Generation
The Power PMAC machine controller from Delta Tau features a powerful CPU and a 2-GB program buffer for better computational power and trajectory generation. According to the company, the controller provides path accuracy and smoothness for improved surface quality and reduced path errors. A lookahead function algorithmically evaluates trajectories before execution, optimizing speed, acceleration and smoothness while ensuring that no previously specified acceleration or velocity limits are violated on any axis.
The controller improves parameters aimed at maintaining path fidelity, including control of the trajectory data resolution, independent control of coordinate system acceleration/deceleration times, and an axis-by-axis control of maximum motor acceleration. Also included are application-specific parameters, such as blended move corner acceleration limitation, a corner angle break point setting and a corner radius setting, for applications that are sensitive to motion control capabilities including 3D contouring, micromachining, engraving, waterjet, plasma and laser machining, for example.
For higher servo gains and improved path accuracy, the controller incorporates a variety of new tuning algorithms. A position-velocity loop setup utility enables creation of position and velocity loop filters, including single, double and low pass filters of various orders. Other tuning feature include a trajectory pre-filter utility that removes the effects of low-frequency resonances and an adaptive control function that enables the user to dial in a desired servo stiffness.
In conjunction with Cam-Sculptor software, the controller supports table-based “electronic cams” which enable development of customized cyclic optimal trajectories for one motor as a function of a second motor’s position. It also automatically calculates the necessary torque offset values and enables specification of digital outputs at different “cam-generated” zones.
While the mistakes listed here will not sound an alarm or cause a program to fail, they will cause confusion, wasted time and scrap parts.
Effectively commanding motion on most CNC machines requires more than describing how the CNC machine determines the end point position for each motion.
This perspective for a good programmer is a practical one, since the CNC operator must understand the machine's basic components, its directions of motion, and all buttons and switches available on the machine tool itself.