Electric Linear Actuator Applications
Electric linear actuators are indispensable key components in many intelligent devices, industrial automation, and mechanical equipment. They are capable of providing precise linear motion, and are widely applied in medical equipment, warehousing and logistics, agricultural machinery, and many other fields.However, linear actuator true potential can only be harnessed when we understand how to control linear actuator position accurately. This article aims to provide an in-depth understanding of the process of controlling the position of a linear actuator with potentiomete.
Electric Linear Actuator Working Principle
The basic working principle of a linear actuator is simple - by switching the positive and negative poles of a DC power source, the linear actuator can be driven to extend and retract. However, if more precise position control is required, it is necessary to utilize the built-in position feedback circuit of the linear actuator. Typically, a linear actuator is equipped with a 10K ohm potentiometer, and by measuring the output resistance or voltage of the potentiometer, the current position of the linear actuator can be accurately obtained. Let's discuss two common control methods in detail below.
Position Control Based on Resistance Measurement
The electric linear actuator usually has a five-core cable, where the red and black lines are two power lines of the electric linear actuator, and white, blue and yellow wires are the three output wires of the potentiometer. The blue and yellow wires are connected to the two terminals of the potentiometer, it is a fixed resistance value. When the linear actuator moves, the resistance value between white wire and yellow wire or white wire and blue wire changes accordingly. In this way, we can obtain the corresponding movement position of the linear actuator by measuring the resistance value. When the linear actuator is extended outwards, the resistance value between white and blue wires will decrease accordingly, and the resistance value between white and yellow wires will increase accordingly. When the linear actuator is retracted inward, the resistance value between white and blue wires will increase accordingly, and the resistance value between white and yellow wires will decrease accordingly.
When the resistance value between white wire and yellow wire is 0.8K ohms, and the resistance value between white wire and blue wire is 9.2K ohms, the linear actuator is at the 0mm position.
When the resistance value between white wire and yellow wire is 4.5K ohms, and the resistance value between white wire and blue wire is 5.5K ohms, the linear actuator is extended to the 100mm position.
When the resistance value between white wire and yellow wire is 9.1K ohms, and the resistance value between white wire and blue wire is 0.8K ohms, the linear actuator has reached the maximum stroke of 200mm.
By real-time monitoring the changes in these resistance values, we can accurately control the motion position of the linear actuator. This resistance-based detection method is simple and practical, and has a wide range of applications.
Position Control Based on Voltage Ratio
In addition to measuring resistance, we can also precisely control the position of the linear actuator by regulating the voltage ratio between the white and yellow wires.
First, provide a DC input voltage to the blue wire terminal (positive +) and the yellow wire terminal (negative-). Then, measuring the ratio of the voltage between the white wire and the yellow wire to the input voltage to obtain the corresponding motion position of the linear actuator.
When the measured the voltage between the white wire and the yellow wire is 1V, the linear actuator is at the 0mm position.
When the measured the voltage between the white wire and the yellow wire is 5.5V, the linear actuator is extended to the 100mm position.
When the measured the voltage between the white wire and the yellow wire is 11V, the linear actuator has reached the maximum stroke of 200mm.
This voltage ratio-based control method is also simple and practical. By monitoring the ratio between the white-yellow voltage and the input voltage, we can likewise obtain precise position information of the actuator.
These two control methods have their own advantages and disadvantages. The resistance detection method is simple to operate, but requires prior knowledge of the potentiometer's resistance parameters. The voltage ratio method does not require knowledge of the potentiometer parameters, but needs to provide an additional fixed voltage source. In practical applications, the appropriate scheme can be selected based on specific requirements.
In summary, regardless of which control method is adopted, by reasonably utilizing the built-in position feedback circuit of the linear actuator, we can achieve precise control of the actuator's motion position. This provides a reliable solution for the development of various intelligent devices, industrial automation, and mechanical equipment.
By sharing two common position control methods, hoping that it will be of some inspiration to your research and development in related fields. Stay tuned to our blog for more insights into the world of linear actuators and other cutting-edge technologies.
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