Classification and Characteristics of Servo Motion Control System

Jan 26, 2022

Classification and Characteristics of Servo Motion Control System

As a professional provider of imported servo control solutions, we can help customers select a servo control system that meets the requirements. Our company has reached cooperation with many foreign servo control suppliers, such as B&R, BECKHOFF, WEG, NIMPEX, PARKER, SIEMENS, HEIDENHAIN, etc. Professional answers to customer needs.

1. Open loop servo system
Open-loop servo system, generally speaking, only has input and output, no feedback, and its driving components are mainly power stepper motors or hydraulic pulse motors. The essence of the working principle of these two driving elements is the transformation from digital pulses to angular displacement. It does not use position detection elements to achieve positioning, but relies on the driving device itself. The angle turned is proportional to the number of command pulses; The frequency of the given pulse is determined.
The structure of the open-loop servo system is simple and easy to control, but the precision is poor, the low speed is unstable, and the high speed torque is small. In the past, it was generally used on light-loaded or economical CNC machine tools. However, due to the development of technology and market demand, it is no longer suitable for large-scale, high-speed, high-torque, and high-precision servo systems.

2. Semi-closed loop servo system
The position detection element is not directly installed on the final moving part of the feed coordinate, but is converted through the position of the mechanical transmission part in the middle, which is called indirect measurement. That is, a part of the transmission chain of coordinate motion is outside the position closed loop, and the transmission error outside the loop is not compensated by the system, so the accuracy of this servo system is lower than that of the closed loop system.
The control structure of the semi-closed loop and the closed loop system is the same, the difference is that the closed loop system includes more mechanical transmission components, and the transmission error can be compensated. Theoretically, the accuracy can be very high. However, due to the influence of mechanical deformation, temperature change, vibration and other factors, the system stability is difficult to adjust. In addition, after the machine tool runs for a period of time, due to the wear and deformation of mechanical transmission parts and changes in other factors, it is easy to change the stability of the system and the accuracy. Therefore, more semi-closed loop systems are currently used. Only use the full-closed-loop servo system on high-precision CNC machine tools with high compactness of transmission components, stable performance, and little change in temperature difference during use.

3. Closed-loop servo system
The closed-loop servo system is an error-controlled servo system. The error of the CNC machine tool feed system is the difference between the position command output by the CNC and the actual position of the machine tool table (or tool holder). The motion actuator of the closed-loop system cannot reflect the position of the motion, so a position detection device is required. The device measures the actual displacement or the actual position, and feeds the measured value to the CNC device, compares it with the command, obtains the error, and forms closed-loop position control in turn.
Because the closed-loop servo system is feedback control, and the feedback measurement device has high precision, the error of the system transmission chain, the error of each element in the loop and the error caused by the movement can be compensated, thus greatly improving the following accuracy and positioning accuracy.

Common well-known European servo motion control system providers

B&R, Austria (B&R)
B&R is a global leader in automation technology, headquartered in Eggelsberg, Austria, founded in 1979 by Mr. Erwin Bernecker and Mr. Josef Rainer. The belief in innovation accompanies B&R's continuous growth and leads the trend of technological development. Today's B&R has established branches in 60 countries around the world, with 155 offices. B&R servo drives and inverter modules feature hard-wired or integrated safety technology for intelligent responses to hazardous situations. In addition to minimizing downtime, this greatly increases machine output. B&R servo technology is ideal for centralized and distributed architectures. Whether located in the control cabinet or directly on the machine, the product portfolio includes drive solutions for any situation.
A wide range of motors, gear units and motor/reducer combinations are available. Components developed by B&R meet the specific needs of standard and special-purpose machinery in every industry – from metalworking to food and beverage. For extremely fast delivery, you can choose from a list of standard motors.

Beckhoff Germany
Since the company was founded in 1980, Beckhoff has always adhered to PC-based control technology and developed a large number of innovative products and solutions, which is why Beckhoff has continued to grow. Early concepts from Beckhoff have become the standard for many automation technologies and have been successfully introduced into the market.
Beckhoff is based on the concept of PC control technology and the launch of the Lightbus system, Bus Terminals and TwinCAT automation software, which has a milestone historical significance in the field of automation technology. In the traditional control industry, these products have been widely accepted as high-performance solutions. EtherCAT - the real-time Ethernet solution - is a forward-looking high-end technology, a new generation of cutting-edge control concepts.

Siemens (SIEMENS):
Motion control system SIMOTION
SIMOTION plays a pivotal role in the field of motion control, it is a scalable, modular, high-performance motion control system that can be adapted to centralized or distributed machine design, and can provide various solutions based on PC, controller or drive. The high performance, high flexibility, easy engineering and quick commissioning of the system meet the unique needs of users.
Other Siemens drive technologies: Siemens provides drive technology products that are unparalleled in the world, including Siemens inverter SINAMICS, CNC system SINUMERIK, reducer, geared motor, coupling, hybrid drive and other series, as well as Siemens motor SIMOTICS, etc., covering all Torque ranges, performance classes and voltage classes.

BOSCH REXROTH:
The IndraMotion servo system from Rexroth is the system solution for fast machining centers in harsh industrial environments. Superior performance and a wide range of technical functions make it a control system capable of meeting specific requirements. Up to 64 axes can be controlled with 12 independent CNC channels, 32 of which are spindle-capable axes. The system also includes future-proof Industrial Ethernet with Sercos as well as PROFIBUS and Fast Ethernet. In addition, there is a wide range of functions for complex interpolation, axis coupling, special motion, fast input/output coupling, and more.

HEIDENHAIN, Germany:
HEIDENHAIN is a world-renowned expert in measurement and servo motion control systems. The precision measurement technology and products of HEIDENHAIN are widely used in almost all medium and high-end CNC servo system manufacturers around the world. Measurement Feedback Products, Manufacturers

Fagor Spain:
Fagor Spain is a well-known European manufacturer of CNC servo systems and measuring products, and enjoys a high reputation in China. It has won the trust and support of customers with its excellent market performance and cost-effectiveness.

French NUM:
As the second largest CNC system manufacturer in Europe, NUM has been committed to the development and research of machine tool automation and motion control for many years. For 30 years, NUM has been known worldwide for its high-precision, high-speed machining technology, close cooperation with customers, and professional technical support and service.
With more than 30 years of professional experience in the field of industrial automation CNC, specializing in providing CNC solutions and comprehensive CNC products, a European company active in the world, headquartered in Switzerland, the second largest CNC system provider in Europe, and the world's three largest professional CNC systems one of the providers.
NUM's extensive involvement in the fields includes: CNC systems, drives, motors, application software, microcomputer communications and new IT networks, while providing technical services and technical training worldwide.
NUM's main products are: Num power1000 series [1], Axium power series [2], Flexium series [3], Num drive [4], Num axis motor [5], and spindle motor.

According to your actual needs, we can provide you with high-quality European machine tool CNC servo system selection, quotation and project consulting services, looking forward to your consultation.

Ningbo OstBridge Automation Co.,Ltd is an industrial components Bridge to connect worldwide high quality hydraulic, electronic, pneumatic products to customers. We can provide industrial components from brands: REXROTH, PARKER, EATON, MOOG, SIEMENS, B&R, HEIDENHAIN, ect. With years of experiences in market, we can offer our clients the right solution for their specific demand. If you are looking for industrial components, please turn to us for advices.

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