The anti-pinch function of electric sliding doors is a core design feature ensuring personnel safety. Its technical implementation relies heavily on the synergy of sensor detection, motor control algorithms, and mechanical structural protection. Current mainstream solutions construct an anti-pinch system covering the entire movement cycle through multi-dimensional perception and intelligent response, including accurate obstacle identification and dynamic adaptation to different usage scenarios.
Infrared sensors and photoelectric sensing technology form the basic perception layer of the anti-pinch function. Infrared sensors emit infrared beams and receive reflected signals, forming an invisible detection network covering the door's movement path. When the beam is blocked by an obstacle, the sensor immediately captures the signal change and transmits the data to the control module. Some high-end systems employ an array-style infrared layout, achieving millimeter-level obstacle location through the cross-coverage of multiple beams. Photoelectric sensing technology further expands the detection range, utilizing the high directivity of the laser beam to form a dynamic protective strip at the door edge, particularly suitable for high-speed sliding door scenarios.
Pressure-sensing strips and tactile feedback devices constitute the second line of defense in the anti-pinch system. Pressure-sensing strips are typically embedded in the door edge or inside the track and are made of flexible piezoelectric material. When the door comes into contact with an obstacle, the pressure change triggers a redistribution of charges within the material, generating a measurable electrical signal. This design is extremely sensitive to slight touches, even a child's finger or a thin piece of paper can be detected promptly. Some systems also incorporate tactile feedback mechanisms, using vibration or sound to alert the user to the door's status, forming a closed-loop control system of "sensing-response-feedback."
Motor current ripple detection technology analyzes motor operating parameters to determine anti-pinch properties. Brushed DC motors generate characteristic current ripples during commutation, with frequency proportional to speed and amplitude related to load. When the door encounters an obstacle, the motor speed drops sharply, causing a change in ripple frequency, while the increased load causes amplitude fluctuations. The control algorithm monitors these parameters in real time and, combined with initial calibration benchmarks, calculates the current anti-pinch force. If the detected value exceeds a safety threshold, the system immediately triggers motor reversal, with the entire response time controllable within 0.1 seconds.
Hall sensor solutions achieve precise monitoring of position and speed through changes in magnetic fields. A magnetic ring mounted on the motor shaft generates a periodic magnetic field change with rotation, and a Hall sensor converts the magnetic field strength into pulse signals. During door movement, the pulse frequency directly reflects the rotational speed, and the number of pulses corresponds to position information. When an obstacle causes the door to decelerate, the pulse period lengthens, and the control module compares real-time data with a preset model to determine whether to activate the anti-pinch program. This solution offers high positional accuracy but requires additional magnetic rings and sensors, resulting in relatively high costs.
Mechanical structural protection design provides physical redundancy for the anti-pinch system. The door edges are rounded and wrapped with elastic materials to reduce impact forces. The track system features an anti-derailment structure to ensure the door maintains a stable trajectory when encountering obstacles. Some high-end products also install anti-pinch strips at the bottom of the door, embedding conductive rubber and resistance wires to form an independent pressure detection circuit. When the strip deforms under pressure, the change in resistance triggers the anti-pinch signal; this design is particularly suitable for scenarios with high sealing requirements.
The adaptive capability of the control algorithm is key to the intelligence of the anti-pinch function. Modern systems continuously optimize the anti-pinch force threshold and response strategy through machine learning technology. The algorithm records operational data under different environmental conditions, including parameters such as temperature, humidity, and voltage fluctuations, and automatically adjusts the detection sensitivity. For example, in low-temperature environments, material shrinkage may cause changes in the anti-pinch force; the system maintains stable performance through a compensation algorithm. This adaptive mechanism significantly improves the reliability of the anti-pinch function and reduces false triggering.
Multi-technology integrated anti-pinch solutions are becoming an industry trend. High-end electric sliding door systems typically integrate multiple technologies such as infrared, pressure, and current detection, achieving complementary advantages through data fusion algorithms. For example, infrared sensors quickly identify obstacles, pressure-sensitive strips provide precise touch feedback, and current detection monitors the motor's operating status. The control module comprehensively analyzes multiple signals to make the optimal decision. This composite solution significantly improves the robustness of the anti-pinch system, enabling it to cope with complex and ever-changing real-world application scenarios.
