The difference between motor control and motion control

From the point of view of concern, motor control (here refers to servo motors) is mainly concerned with controlling one or more parameters in the rotation, speed, and position of a single motor to reach a given value. The main focus of motion control is to coordinate multiple motors to complete the specified motion (synthetic trajectory, synthetic velocity), focusing on trajectory planning, velocity planning, kinematic transformation; For example, the CNC machine tool should coordinate the XYZ axis motor to complete the interpolation action.

Motor control is often used as a part of the motion control system (usually a current ring, working in torque mode), more focus on the control of the motor, generally including position control, speed control, torque control three control rings, generally no planning ability (some drivers have simple position and speed planning ability).

Motion control is often for products, including mechanical, software, electrical and other modules, such as robots, drones, motion platforms, etc., is a real-time control management of the position and speed of mechanical moving parts, so that it can move according to the expected trajectory and specified motion parameters.

Some of the contents of the two are overlapping: the position ring/speed ring/pitch ring can be implemented in the driver of the motor, and can also be implemented in the motion controller, so the two belong to the easy to confuse.

1. Basic structure composition

The basic architectural components of a motion control system include:

Motion controller: Used to generate track points (expected output) and close position feedback loops. Many controllers can also close a speed loop internally.

Motion controllers are mainly divided into three categories, which are PC-Based, special controller, PLC. PC-Based motion controllers are widely used in electronics, EMS and other industries. The representative industries of special controllers are wind power, photovoltaic, robots, molding machinery and so on; PLC is favored in rubber, automotive, metallurgy and other industries.

Driver or amplifier: A signal used to convert a control signal (usually a speed or torque signal) from a motion controller into a higher power current or voltage signal. The more advanced intelligent drive can close the position loop and speed loop itself for more precise control.

Actuator: such as a hydraulic pump, cylinder, linear actuator or motor, used to output motion.

Feedback sensors, such as photoelectric encoders, rotary transformers or Hall effect devices, are used to feedback the position of the actuator to the position controller to achieve closure of the position control ring.

A wide range of mechanical components are used to convert the motion form of the actuator into the desired motion form, including gear boxes, shafts, ball screws, toothed belts, couplings, and linear and rotating bearings.

Second, from the motion controller to see the motion control

The emergence of motion control is more conducive to electromechanical control solutions, such as the CAM and gear used to require mechanical structure, now can use electronic CAM, electronic gear to achieve, eliminating the mechanical realization process of backtravel, friction and wear.

Mature motion control products not only need to provide path planning, forward-looking control, motion coordination, interpolation, kinematics forward and inverse solutions, and drive motor command output, but also need to have engineering configuration software (such as SIMOTION's SCOUT), syntax interpreters (not only referring to their own language, And includes IEC-61131-3 PLC language support), simple PLC functions, PID control algorithm implementation, HMI interactive interface, fault diagnosis interface, advanced motion controller can also achieve security control.

Third, the development trend of motor control

According to the market research report released by MarketsandMarkets, the global motion control market in 2022 (including spare parts: AC motors, motors, motion controllers, AC drives, electronic drives; Applications: Packaging, Material Handling, Metalworking, Conversion, Positioning) is expected to reach $22.84 billion, growing at a 5.5% CAGR between 2016 and 2022.

As far as motion controllers are concerned, with the expansion of industry applications, China's motion control market has gradually matured, and most downstream machinery industries such as machine tools, engraving machines, semiconductors, industrial robots, EMS, and material handling have achieved good development. Especially in the lithium battery, industrial robots, semiconductors, EMS and other industries, Europe, the United States and Japan motion control manufacturers outstanding performance, with a strong comprehensive competitive advantage.

Because the goal of motion control is to complete the production line process to manufacture products, in the middle of the motion control process, in fact, is not the most important, but how to correctly meet the requirements in real time, is the most important function; In addition, various products now have higher and higher precision requirements, more and more stringent requirements for the process, and motion control is real-time and accurate, to achieve optimization, it is necessary to integrate a variety of related technologies, such integration is regarded as the most difficult control technology.

Dedicated controllers will remain the dominant motion controller type in the industrial robotics industry for some time. The PC-Based motion control market in the semiconductor industry has developed steadily, with a growth rate of about 17%. The increased demand for machine vision capabilities in the logistics industry has led to a gradual increase in the PC-Based proportion. In the traditional printing machinery is still dominated by PLC motion controller, the application of PC-Based motion controller has just started, and it is used more in the emerging digital printing machinery, and will increase slightly in the future.

Source: Operations Control CMCIA