The core technologies of stage machinery are the key to achieving safe, precise, and flexible movement of stage equipment; they primarily encompass aspects such as mechanical transmission, automation control, and multi-device coordination. In the context of stage machinery, "lifting transmission" refers to a technical system that utilizes specific mechanical structures and power systems to drive stage equipment in a vertical direction. Its core function is to convert power into controllable vertical motion, thereby meeting the demands of theatrical performances regarding spatial transformation, special effects realization, equipment positioning, and performer staging.
Common lifting transmission methods employed in stage machinery include rigid chain drives, flexible rack drives, screw jack drives, large-screw drives, chain drives, wire rope drives, and scissor-lift drives. Rigid chain drives are suitable for use in relatively shallow foundation pits; they are characterized by high transmission efficiency, high load capacity, high precision, and relatively high operating speeds. However, they entail stringent manufacturing requirements and high production costs, and are primarily utilized in applications such as lifting orchestra pits. Flexible rack drives utilize an assembly-type rack that is capable of bending in a single direction to form a lifting mechanism. Screw jack drives offer high load capacity, possess inherent self-locking properties (preventing back-driving), and provide high precision; however, they are characterized by low operating speeds, low transmission efficiency, and high noise levels. Consequently, they are predominantly used in systems requiring medium-to-low speeds, high loads, and high precision - such as lifting stages where safety requirements are paramount. Large-screw drives are suitable for shallow foundation pits; they operate at relatively low speeds, generate significant noise, and impose stringent protection requirements on the control system. They are primarily applied in lifting orchestra pits and retractable seating systems. Chain drives boast high transmission efficiency and are suitable for long-distance, medium-to-high speed, and heavy-load applications; however, they are prone to generating noise and vibration during high-speed operation and entail higher maintenance costs. They are primarily utilized in applications such as main stage lifting systems. Wire rope drives offer a dynamic load-bearing efficiency of approximately 85% and demonstrate exceptional resistance to impact loads, making them suitable for long-distance and high-speed transmission. Nevertheless, they exhibit lower transmission precision and require periodic maintenance; they are primarily utilized for applications such as lighting battens, scenery battens, and single-point hoists. Scissor-lift drives are suitable for shallow foundation pits; their operating speed and noise levels vary depending on the accompanying transmission mechanism. They possess relatively weak resistance to horizontal forces but offer moderate production costs, making them primarily suitable for applications such as small lifting platforms.
The PLC-based automation control systems for stage machinery represent the cutting edge of technological development in the field, with the entire system designed around a modular architecture. At its core, the system utilizes PLCs - such as the Siemens S7-200 series - as primary controllers, employing the MODBUS bus protocol to ensure highly reliable communication. Industrial-grade photoelectric encoders serve as the system's sensors. Key functionalities include the precise control of stage battens and similar equipment - enabling free vertical movement, positioning, and stopping - as well as the ability to set upper and lower travel limits and specific positioning points at any location along the travel path. The system supports the configuration of over 100 distinct scenes within a single performance; each scene is capable of simultaneously controlling multiple battens. Furthermore, the system features an automatic learning and correction mechanism for positioning errors, ensuring an operational accuracy of less than 1 cm. System highlights include flexible configuration options, exceptional reliability, comprehensive multi-level fault diagnostics, and a triple-redundant limit protection system, all managed through an intuitive graphical user interface.
Multi-motor synchronous control technology constitutes one of the core pillars of modern stage automation, as a wide array of stage equipment - including lift platforms, lighting battens, and more - necessitates the synchronized operation of multiple motors. To address the specific synchronization requirements of lift platforms, lighting battens, and similar devices during live performances, the system employs an "electronic virtual master axis" control algorithm as its central synchronization engine. Typically, this system utilizes Siemens PLCs as main controllers, MM440 variable frequency drives (VFDs) for motor actuation, and photoelectric encoders for position sensing. Communication is facilitated via robust, real-time distributed control networks - such as Profibus-DP - thereby enabling the rapid, precise, and safe synchronized operation of various stage devices.