Sunset Dynamics was tasked to devise a winch and multi-axis track system for an acrobatic theater performance that allowed performers to fly. They needed an affordable solution with a quick development time to coordinate the winch/track systems. After extensive research Sunset Dynamics found their complete solution in the Rabbit’s BL2600 Single-Board Computer.
The winches are very important for the success of the show. Performers and those involved heavily depend on the winches accuracy and timing to compliment the shows overall effect.
Each winch/track system is tied to an Ethernet based network along with a PC that provides the motion cues. Each winch is programmed to recognize instructions sent by the PC to orchestrate movements throughout the performance. "This system is engineered to fly a 250-pound load, up to 5-feet per second, with 70 ft cable drum capacity and positioning precision of +/- 0.01 in," says Ryan Niemi, owner of Sunset Dynamics.
Sunset Dynamics uses the BL2600 Single-Board Computer to perform very important control, monitoring, and reporting functions. The company chose the BL2600 since it was a complete cost-effective solution. "Our solution before was to set up a PC with custom PCI card containing the various I/O functions," says Niemi, "but it's not too convenient to have a PC sitting next to each winch, 120 feet up on a catwalk somewhere." Mr. Niemi decided to move to a custom in-house PLC system. "PLC allowed the complete control package to fit in a small enclosure at the winches," Mr. Niemi admitted and revealed some limitations,"One very significant stumbling block with the PLC approach is it’s very difficult to achieve hard real-time control in which specific tasks or operations happens at a know interval or point in time." Other factors such as inconvenient PLC programming, limited performance, and long development cycles, forced Sunset Dynamics to look for alternatives. Luckily they came across the BL2600.
"BL2600, there’s really no question that it’s the best solution for our application and slightly less expensive than we could’ve built our own motion control boards for anyway," said Mr. Niemi. What would take several components and long development time has been condensed into a quick-to-market solution. The BL2600 is feature rich and provides plenty options. "The ability of the BL2600 to output +/- 10 V was a significantly important feature for motion control, " says Niemi, "The variable frequency drivers take +/- 10 V input as a speed and/or torque input." The analog inputs also provide a means to take measurements, such as temperature, to help cool the winch down using a heat sink system. Other features, such as high current outputs and ethernet capabilities, allow the BL2600 to directly power relays and cooling systems as well as to keep real time control via a network. The plethora of serial ports provided Mr. Niemi with an array of options such as monitoring the status of the motor and connecting an operator interface for preliminary setup. Rather than having several different components controlling different things, the BL2600 is a complete package that maintains all functions from the board itself.
Manufacturers of motion control and consulting groups, like Sunset Dynamics, need to develop solutions quickly for their clients. Some of these performance groups are heavily dependent on these machines for stunning visual imagery. For Niemi, Dynamic C has been very instrumental in helping him bring his solution to quick development, "Compared with brewing up our own motion control board and producing the firmware from scratch, the established code base included with Dynamic C allowed very rapid software development." Dynamic C and its vast software libraries enable customers such as Niemi to quickly develop complete functionality as well as implement changes before or during a show. With these quick turn around times the show will go on.
The Rabbit 3000 processor provides Sunset Dynamics the power needed to run the "flight" software smoothly. One feature that Mr. Niemi liked is the quadrature decoder that is built into the Rabbit 3000. "The quadrature decoder allows (almost) direct interfacing of rotary quadrature encoders on the motor and cable drum spindle shaft to measure position," says Mr Niemi, "the decoder can handle sufficiently high speed so that we’re able to measure positions down to 0.01inches while moving at 5 feet per second." The Rabbit 3000 processor provides the reliability and relative accuracy to make sure the performers are in the right place at the right time.
Sunset Dynamics plans to produce a small production batch of the motion systems with BL2600 at the helm. With the price drop, Mr. Niemi is confident that Rabbit’s BL2600 is the complete cost-effective solution for his applications. Sunset Dynamics is located in Klamath Falls, OR .