Variable Speed Control Strategy And Experimental Study Of Long-wall Shearer

At present China is a big country of coal consumption, the total coal consumption accounts for 70% of China's overall fossil energy consumed. Shearer is one of the key equipments in coal production. The cutting unit, as one of the widely used drum shearer's main working part, is made up of driving motor, gear transmission mechanism and rotary drum. As the coal rock's cutting properties are complicated and changeable, the cutting unit load is strongly random, fluctuated and shocked, and because the drum's rotary speed is unadjustable, these two factors make the cutting unit the easiest failure prone part of the shearer, and also lead to a bad adaptability on working condition. But the dangerous and deep coal mining unmanned operation developing trend requires a far more reliable cutting unit with better working condition adaptability, this makes it meaningful to study the shearer's working characteristics, so the way that can reduce the drum's and cutting unit's load while the productivity is also maintained could be figured out.According to the 4th task of The National Major Basic Research Program of China(973 Program, Grant No. 2014CB046304), the investigations in this paper includes the followings:1. Based on the analysis of the influence factors of the shearer's drum load and productivity, two speed control strategies of the shearer are proposed to reduce load of the drum and the cutting unit transmission system. To verify the effectiveness of the two proposed shearer speed control strategies, a simplified pure torsional model of the cutting unit is developed and the simulation is carried out. At the same time, because the shearer cutting unit is a system with a large moment of inertia, so the effect of inertia on the dynamic load of the transmission system in the speed adjusting process is studied to optimize the proposed shear speed control strategies.2. In order to verify the proposed shear speed control strategies by testing, a test bench was designed and set up, besides a real time control system based on dSPACE is also developed. Based on that, the basic performances testing of the test bench is carried out firstly.3. To reduce the similar inertia torque interference caused by the test bench's inertia in the flywheel's speed variable process, a method of feed-forward control combined with fuzzy PI is proposed to improve loading precision and response performance of the test bench loading system. After the model simulation has verified the effectiveness of the proposed test bench loading system control method, the proposed loading system control method is applied to the real test bench. The followed experiment results indicate that the proposed loading system control method can eliminate the interference of additional moment of inertia generated in the flywheel's variable speed process and load accuracy and response speed are also improved, making the test bench meets requirements of the test.4. Based on the optimized test bench, the mechanical and electrical dynamic characteristics tests of the cutting unit are studied. The results show that the mentioned shearer speed control strategies can reduce the load of the drum and cutting transmission system under the mutation load with its productivity maintained as high as possible.