The closed-loop step become motion control scheme of one

The closed-loop step become motion control scheme of one
You are familiar with the traditional way of stepping motor control. If adopted feedback device or senseless control way, can for safety, reliability and precision higher demand movement control applied to rotary joints provide a more economical choice.
Most based on the step motor sports system are running in the open loop condition. Therefore to provide low cost solutions. In fact, step into the system is the only one not need feedback position control ability has the movement of the technology. But when stepping motor driven by the open loop way of loading, steps and actual step instructions in between the potential lost synchronization.
Closed loop control as traditional stepping motor control of supplement, for a higher safety and reliability of the product quality or the application to
rotary union provide cost-effective option. Feedback device or some indirect parameter examination way in this kind of stepping system "closed loop", in order to verify/control out-of-step, testing motor stall, and ensure a more effective torque output. Recently, stepping closed-loop control (CLC) in intelligent motion system structure distributed also play a role.
Feasible closed-loop control method and its advantages
There are several technologies can be used for step motor position, velocity, and/or torque closed-loop control. According to the control of increasing degree arrangement, these technologies include: Step back emf project. (emf) detection and all the servo control (see "closed-loop control methods", adding that the).
National Instruments (NI) company industrial control product manager Rahul Kulkarni mentioned a few to the closed loop stepping control of reason and apply occasions:
"No parameters to adjust; The system is easy to build, can generally do free maintenance.
"In the continuous motion is allowed in the use of breakpoint trigger cameras or data collection equipment.
Second-ranking position control overshoot, on some occasions this overshoot is not allowed, for example nano fabrication or semiconductor processing.
In the end correct position deviation movement.
The last one, although need according to system load and inertia asked to
fiber optic rotary joint choose appropriate size of stepping motor, but may not need so strict. "In practical work, if your application to the path or track without the strict requirements, you can slightly reduce motor specifications and grades to save costs. This is a closed loop stepping control can play a role in the first place." Unlearn said.
NI Company all the motion controller-NI 733 x (can only be used for stepping) and NI 734 x and high performance module NI 735 x (step/servo) -can be configured to step on to closed-loop control. According to his explanation, in CLC mode, stepping shaft with orthogonal encoder or analog input to the position and speed feedback.
Balder electric company thinks. The step motor is simple, cheap to make it become a location to load control ideal choice. Balder electric motor company product manager John Mazurkiewicz explained, use the step motor reasons include: the operation is simple (usually in the open loop state used); owing to accept digital pulse input and become easy and other equipment interface; low cost, because generally don't need feedback device.
However, the open loop running will bring out-of-step risk, and not cause orientation. "People perceive the mistake happened in the production line, often have a lot of defective goods," he said. "In addition, when moving a heavy load and make more step motor in maximum torque work near, and in order to improve productivity and improve the acceleration, have higher out-of-step stall risk." Increasing feedback to avoid the traditional step motor these limits.
The closed-loop stepping motor can use low cost encoder, this is relative to those in the servo system for the use of the encoder, and this leads to a further advantage: "Usually, stepping applications that use the oil encoders, and you don't need to electronic commutation feedback signal." Mayacaceae added.
According to Baldor point of view, CLC step motor light load and very short mobile particularly effective. Typical industrial applications include CNC system, process control and printing and packaging system of the X-Y table and the rotating positioning equipment.
Parker Hannifin/Compumotor company zero velocity stability requirement and position calibration of the request occasions recommend using closed loop stepping movement. "Stepping motor can well meet the requirements, and the demand is the current mainstream needs." Project manager John Walewander said. Parker had no sensor technology had a lot of investment, and has developed a patent of digital technology, it does not need additional devices external were needed for the closed-loop task, which replaced the motor of the feedback device.