What is motion control? The basic structure of motion control system

What is motion control?

Motion control (MC) is a branch of automation that uses devices such as hydraulic pumps, linear actuators or servo mechanisms to control the position or speed of a machine. The application of motion control in the field of machine tools is more complex than that in special machines, which have simpler motion forms and are usually called general motion control (GMC). Motion control is widely used in packaging, printing, textiles and assembly.

Features

The basic structure of a movement consists of:

A motion controller is used to generate trajectory points (desired outputs) and close the position feedback loop. Many controllers can also close a velocity loop internally.

A drive is used to convert the control from the motion controller (usually a speed or torque signal) into a higher power or voltage signal. More advanced drives can close the position and speed loops themselves for more precise control.

An actuator such as a hydraulic pump, pneumatic cylinder, linear actuator or motor is used to output motion.

A feedback such as a resolver or Hall effect device is used to feed the actuator position back to the position controller to close the position control loop.

Numerous mechanical components are used to convert the motion of the actuator into the desired motion, including gearboxes, shafts, ball screws, toothed belts, couplings, and linear and rotary bearings.

Typically, the functions of a motion control system include:

Speed ​​control

Point control (point to point). There are many ways to calculate a motion trajectory, which are usually based on a motion speed curve such as a triangular speed curve, a trapezoidal speed curve or an S-shaped speed curve.

Gear (or electronic cam). That is, the position of the driven shaft follows the position change of a driving shaft. A simple example is that a system contains two turntables, which rotate according to a given relative angle relationship. Electronic cam is more complicated than electronic gear. It makes the following relationship curve between the driving shaft and the driven shaft a function. This curve can be nonlinear, but it must be a functional relationship.

System composition

1. Motion controller: used to generate trajectory points (desired output) and close the position feedback loop. Many controllers can also close a velocity loop internally.

Motion controllers are mainly divided into three categories: PC-based, dedicated controllers, and PLC. PC-based motion controllers are widely used in electronics, EMS and other industries; representative industries for dedicated controllers are wind power, photovoltaics, robots, molding machinery, etc.; PLCs are favored in rubber, automobile, metallurgy and other industries.

2. Driver or amplifier: used to convert the control signal (usually speed or torque signal) from the motion controller into a higher power current or voltage signal. More advanced intelligent drivers can close the position loop and speed loop by themselves to obtain more precise control.

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

4. Feedback sensor: such as photoelectric encoder, rotary transformer or Hall effect device, used to feedback the position of the actuator to the position controller to achieve the closure of the position control loop. Many mechanical components are used to convert the motion of the actuator into the desired motion, including gearboxes, shafts, ball screws, toothed belts, couplings, and linear and rotary bearings.

Industry Analysis

Motion control is a hybrid fusion of many technologies including mechanics, machinery, and automation control. Obstacle avoidance control in the motion control of industrial robots is more about the application of industrial robots in actual production. It is also the learning and application of technology in the entire industrial background. It exercises how to adapt to the knowledge learned in real industrial production and examines the ability to fully grasp knowledge under comprehensive literacy. Nowadays, people pay more attention to innovation and logical ability, rather than the single vision and thinking method of seeing the mountain as a mountain. However, many studies are faced with time pressure, huge knowledge pressure, and the trouble of how to learn efficiently. How to build a huge amount of information in the mind and call out the required knowledge points at any time has become the focus of the technicians' learning courses, and its greatest role is to be able to summarize all the content, present a well-structured knowledge network, enhance the technicians' sense of logic, and fully grasp the industrial knowledge. When facing mechatronics problems, the acquisition of basic conditions may involve knowledge of establishing spatial coordinates, and the establishment of circuit templates may involve knowledge of kinematics. The ability to analyze the knowledge points tested in the face of problems and to skillfully apply each of these knowledge points is actually what technicians need most in their learning, and it is also the biggest challenge. At the same time, we must also attach importance to the opportunity to learn professional skills again. The improvement of talents is the progress of the entire team. Continuous further study is also a process of integrating new concepts, and the specific application in the obstacle avoidance and control activities of industrial robots is a driving force for renewal and development.

Since the designers of industrial robots design different internal structures according to different needs, the motion tracking of industrial robots is also purposefully designed and is an important part of the motion control of industrial robots. In such motion tracking designs, most of them use line detection methods to move the external trajectory. The infrared detection method is mainly based on the different properties of color reflection of different objects as the characteristic principle. This is mainly based on the use of the vehicle body to release infrared light to the outside, observe the absorbed light after refraction of the light, and analyze the external conditions based on the absorbed light. At the same time, it is also necessary to consider that the actual range of action of infrared detectors is not large and is restricted by the range of motion. This also requires the installation number and operating status of the sensor to be scientifically and reasonably set in terms of speed. At the same time, the steps of the motion tracking experiment of the industrial robot are carefully planned, and the technicians are arranged to learn and understand the experimental steps in advance to ensure the safety of the experiment and avoid accidents. Therefore, the experimental activities must be carried out under the safety of the technicians, and unexpected results must not be lost. Strive to achieve the best effect of industrial robot motion control.

Editor: Huang Fei