Achieve distributed motion control in a modular pick and place machine.
Create motion control architecture that simplifies programming, provides fast pick & place transfers, and supports multiple motor types.
Feature / Function
Board (or Card) based
# of Axes
4 per unit
Point-to-point, multi-axis point-to-point
Motion Control Solution
An implementation using Prodigy® Stand-Alone Motion Cards for each of the modular units in the Pick & Place machine resolves several issues. The three axes for the pick & place gantry benefit from S-curve motion profiles for smooth operation and feed-forward control for faster system performance. Utilizing the downloadable programming capabilities enables the motion cards to off-load the motion programming execution from the PC host allowing it to focus on running the overall system application and eliminates the need for a PC host controlling each modular unit.
C-Motion Development Software
PMD Corp.'s C-Motion® command library can be used to develop code that runs on the motion card independently of a host PC, freeing the host PC to focus on other machine application software. C-Motion is the foundation from which the programming code is developed. It enables machine designers to quickly program motion into demanding applications using standard C/C++ programming. A suite of software tools is provided with the Prodigy Motion Cards in addition to C-Motion to facilitate the creation and downloading of the programs within a PC environment. These include a programming editor, compiler, download utility and debugging tool.
S-Curve Motion Profiling for reduced vibration
Adding S-curve motion profiles can substantially reduce vibration over trapezoidal profiles. This translates to significantly faster transfer speeds. Often, only a small amount of "S" (transition between acceleration and no acceleration) can substantially reduce induced vibration. The form of the s-curve will depend on the desired performance required. Prodigy Motion Cards which include the Magellan® Motion Processor can also provide trapezoidal, velocity contouring, and electronic gearing motion profiles as alternatives to s-curve profiles.
Adding feed-forward velocity and acceleration to the position loop minimizes the tracking error without having to increase the PID gains. This minimizes the risk of making the control loop unstable when trying to maximize performance of the system. In a Pick & Place application this will allow for faster motion profiles and therefore higher throughput in each module.
Multi-motor type support
Prodigy supports multiple motor types, DC brush, Brushless DC, and stepper, and also pulse & direction amplifiers. Each axis on a card can be a different motor type, e.g., Brushless DC with lead screw or linear motor. This allows for optimized motor selection in the system for both cost and performance. Because of this, the system could be simplified using linear motors doing away with the need for a dual encoder configuration. The configurations below show three Brushless DC motors and one with a step motor controlled from one Prodigy Motion Control card.
You may also be interested in:
- Optimize Control of Syringe Dispensing Application
- Field Oriented Control (FOC) - A Deep Dive
- Use Torque FeedForward to Get More from Your Motion Controller
- S-Curve Motion Profiles - A Deep Dive
- Servo Tuning Deep Dive: Black art, rocket science, or walk in the park?