Interference protection device and method for hydraulic support and cutting part of shearer

An interference protection method for a hydraulic support and a cutting part of a shearer comprising the following steps:

• step (1) setting a threshold d of a minimum distance from a second ultrasonic transducer on the hydraulic support to first ultrasonic transducers on the shearer when the shearer gets close to the hydraulic support to a threshold 1, and setting a threshold d of a minimum distance from the second ultrasonic transducer on the hydraulic support to the first ultrasonic transducers on the shearer when the shearer moves away from the hydraulic support to a threshold 2;
• and also setting a time threshold as tthreshold;
• step (2) using an external single-chip microcomputer to control the first ultrasonic transducers and flash lamps on the shearer to simultaneously run and turn off, wherein the first ultrasonic transducers and the flash lamps are turned on at a regular interval of T=1 s;
• step (3) letting i be 0;
• step (4) performing the step (5) if a receiver on the hydraulic support receives an optical signal sent by the flash lamps;
• otherwise, performing the step (6);
• step (5) performing steps (7) to (11) if the second ultrasonic transducer on the hydraulic support receives an ultrasonic signal sent by the first ultrasonic transducers on the shearer;
• otherwise, performing the step (4);
• step (6) recording duration for which the receiver on the hydraulic support fails to receive the optical signal sent by the flash lamps as tfailure;
• and if tfailure is greater than tthreshold, performing the step (3);
• otherwise performing the step (4);
• step (7) letting i be i+1;
• step (8) recording a time point ti at which the receiver receives the optical signal, and a time point t′i at which the second ultrasonic transducer on the hydraulic support receives the ultrasonic signal;
• step (9) calculating a difference between the time points at which the second ultrasonic transducer and the receiver on the hydraulic support respectively receive the ultrasonic signal and the optical signal:
• Δti=t′i−ti;
• step (10) calculating a distance from the second ultrasonic transducer on the hydraulic support to the first ultrasonic transducer on the shearer:
• di=v·Δti, wherein v is a velocity of sound;
• step (11) if i>2, performing the step (12);
• otherwise, performing the step (13);
• step (12) if di≤di−1, performing the step (13);
• otherwise, performing the step (15);
• step (13) recording a current status as a status of the shearer being close to the hydraulic support, and comparing the calculated distance di from the second ultrasonic transducer on the hydraulic support to the first ultrasonic transducer on the shearer with the set threshold 1 of d;
• and if di is less than the set threshold 1 of d, performing the step (14);
• otherwise, performing the step (4);
• step (14) sending out, by a hydraulic support control computer, a signal to control a guard plate to retract, and performing the step (4);
• step (15) recording a current status as a status of the shearer being away from the hydraulic support, and comparing the calculated distance di from the second ultrasonic transducer on the hydraulic support to the first ultrasonic transducer on the shearer with the set threshold 2 of d;
• and if di is greater than the set threshold 2 of d, performing the step (16);
• otherwise, performing the step (4);
• and
• step (16) sending out, by the hydraulic support control computer, a signal to control the guard plate to extend, and performing the step (4).