Research Of Fast And High Precision Control On Electromechanical Leveling System

With recent advances in technology, the accuracy and speed requirements of leveling system are getting higher and higher. The leveling accuracy and stability of the electromechanical leveling system are much higher than the Hydraulic Leveling System for its inherent self-locking and continuous transmission function, though the hydraulic leveling system is widely used in our daily life. Compared with the hydraulic leveling system, it also has some disadvantages, such as bulky structure, low power density and low leveling speed. So the simplified and fast leveled Electromechanical Leveling System is the direction that this paper need to study and research.The electromechanical leveling system used in high precision demands is studied; Performance and support structure are analyzed. Combining with the advantages of fuzzy control and sliding mode variable structure control (SMC), fuzzy Bang-Bang control approach that used in the electromechanical leveling system is proposed by studying fuzzy control and SMC. This approach improves the leveling speed and reduces the system chattering around switch line. An electro-mechanical leveling system controller with STM32 microprocessor is designed, which control the Electromechanical Leveling System to be fast, stable and high precision. Major researches and innovations are summarized as follows:1. Physical structures of electromechanical leveling system are studied; Select the support mode and the number of leg according to the performance requirements. Power system, transmission system and speed measuring system are studied, and the mathematical model of each system is established. Nine tilting modes of Four-point supported leveling system are studied, and the relationships between the lengths of each leg with the tilt degree are given. Introduce the MEMS angle sensor for leveling system and data transfer mode of the angle sensor. Established the mathematical model of the whole electromechanical leveling system with the mathematical model of each part system and tilt-length model.2. The Bang-Bang control approach is studied, and it is introduced to electromechanical leveling system which makes the system run to the aimed position only controlled once. The motor with fixed load running with the highest speed in this process without adjusting the speed which enhanced the leveling speed and it is proved theoretically. Simulation results demonstrate the quickness and effectiveness of the approach; Fuzzy control theory is studied, and four sections fuzzy rules design approach for motor control is proposed. Simulation results show the approach is stable and effective; The poor adaptability with variable load of Bang-Bang control approach is considered; proposed variable switch lines approach which can dynamically adjust the coefficient of switch line, and this approach reduce the chattering of the system and improve system’s ability to adapt the environment. Combining the characteristics of fuzzy control, an adaptive fuzzy Bang-Bang control approach for electromechanical leveling system is proposed. The approach dynamically adjust the coefficient of switch line by fuzzy control and ensure that the Bang-Bang control control the motor run to the aimed position only start and stop once. Also this approach reduces the chattering of the system and improves system’s ability to adapt the environment. The simulation results of the electromechanical leveling system show the approach is adaptive to variable load.3. According to the requirements of the electromechanical leveling system, a Fuzzy Bang-Bang controller is designed by using STM32F103ZET6 as microprocessor. Due to the high voltage and large current when the system running, we adopt voltage isolation method, negative voltage, resistance-capacity absorb, energy control and reasonable PCB layout to improve the EMI/EMC for the controller. The controller using μC/OS operation system to schedule tasks which enhance the control ability of the microprocessor. And design the Fuzzy Bang-Bang algorithm for STM32.4. Test the controller’s ability of controlling the leveling system lifting and descending, and test the static precision of the electromechanical leveling system. And using the controller that running with the fuzzy Bang-Bang algorithm to control the leveling system leveled automatically, and the leveling accuracy is better than 0.05, which meet the design aim. And the experiment shows that the fuzzy Bang-Bang algorithm is correct and practical to electromechanical leveling system.