A fountain is a combination that sprays water or other liquids through a nozzle under certain pressure, forming a specific shape. Modern fountains are generally artificial landscape fountains that rely entirely on fountain equipment. The main purpose is to achieve rhythm and melody through the control of frequency converters. In musical fountains, the changes in water shapes are rich, and combined with lighting, they provide a real and intuitive aesthetic. The various swings in musical fountains allow people to feel the flexible beauty of the fountain. The radial swing is produced by a swinging mechanism set below the water surface, making the water scenery beautiful and pleasing to the eye, giving a magical feeling, which is a manifestation of the high-tech development of the times.
The position and speed changes of the swinging fountain are important factors in creating the elegant style of swinging water shapes. The position sensor of the fountain's swinging mechanism should be a waterproof non-contact positioning device. Commonly used sensors include Hall sensors induced by magnets, photoelectric sensors guided by optical fibers, or rotary position encoders attracted by magnets. For example, the positioning device of a fountain's swinging mechanism that uses a position encoder includes: a position encoder mounted on the swinging motor shaft, a high-speed counter, a control computer, and a communication interface. Since the connecting rod of the swinging mechanism generally has a large gap, to achieve precise positioning, the swinging mechanism can only reach the positioning point from one direction to ensure its repeatability. Therefore, when the swinging mechanism needs to stop, it must reach the positioning point from one direction each time.
The positioning accuracy of the swinging mechanism is affected by the motion torque and resistance torque. The motion torque is determined by the motor's power supply voltage and the speed before stopping, while the resistance torque is composed of the friction of the swinging mechanism, the speed of the water flow, and the surrounding wind force. It can be seen that these are factors that cannot be determined in advance. Therefore, to achieve precise positioning, we must change the control parameters each time. For control parameters that use motor energy consumption braking for precise positioning, there are generally two: the size of the DC braking current and the starting braking time. A more convenient method for computer control is to change the braking time.
In the control system, the motor braking time can be corrected using the detected deviation from the positioning point. Based on the statistical data of the positioning deviation of the swinging mechanism, after mathematical model calculations, the braking time is finally determined.
