What's New in LabVIEW Control Design and Simulation Module 8.5

For more than 20 years, the National Instruments LabVIEW graphical development environment has offered tools to develop and deploy industrial controllers. By combining the NI LabVIEW PID Control Toolkit with the LabVIEW Real-Time and LabVIEW FPGA modules, you can easily implement industrial-grade PID control algorithms. But LabVIEW also has the software libraries you need to analyze physical plants and design and deploy model-based controllers. In this paper, examine some of the new features that the LabVIEW 8.5 Control Design and Simulation Module adds to the LabVIEW software platform.

Product Merge

With previous versions of LabVIEW, engineers conducted plant analysis and control design and implementation using the LabVIEW Control Design Toolkit and performed offline simulation and system implementation with the LabVIEW Simulation Module. To offer a more efficient tool for these tasks, NI has merged these two products into one single module – the LabVIEW Control Design and Simulation Module.

With this module, you can analyze physical plant models that you can obtain both through first principles or using the LabVIEW System Identification Toolkit. It includes a complete suite of analysis functions such as time domain step response or frequency domain body plots. Before deploying, you can simulate both controllers and plants using the simulation loop (see Figure 1), and you can deploy these simulations to real-time targets directly for rapid control prototyping or hardware-in-the-loop applications. The LabVIEW 8.5 Control Design and Simulation Module combines tools for model predictive control and analytical proportional integral derivative control as well as offers increased LabVIEW MathScript support.

Figure 1. Simulation Loop

Model Predictive Control (MPC)[JG1] 

Traditional feedback controllers adjust control action in response to a change in the output setpoint of the plant. Model predictive control (MPC), now included in the LabVIEW Control Design and Simulation Module, is a technique that engineers use to construct controllers that can adjust the control action before a change in the output setpoint actually occurs. This predictive ability, when combined with traditional feedback operation, enables a controller to make adjustments that are smoother and closer to the optimal control action values.

Analytical Proportional Integral Derivative (PID) Control

Finding the proper values for PID controller gains is a process known as tuning the controller. Typically an ad-hoc process, PID tuning involves trial and error. But with the LabVIEW Control Design and Simulation Module, you have the libraries to find sets of PID gain values automatically for a given user model, which ensures system closed-loop stability. You can also input minimum gain and phase margin values to specify the optional performance constraints on the PID controller

Figure 2. Stable Set Boundary for a Third-Order System[JG2] 

Increased LabVIEW MathScript Support

LabVIEW MathScript adds math-oriented, textual programming to LabVIEW. Like graphical programming, you can use LabVIEW MathScript to define the custom software you develop using LabVIEW. Working with LabVIEW, you can choose a textual or graphical approach or a combination of the two. The LabVIEW Control Design and Simulation Module seamlessly integrates into LabVIEW MathScript, adding control-related textual-based math functions. The LabVIEW 8.5 Control Design and Simulation Module expands LabVIEW MathScript integration by adding 18 new functions to increase your control on system construction and connection.

Figure 3. LabVIEW MathScript Node with Control Design Function Calls

Statechart Module Integration

The statechart model of computation offers embedded designers a sophisticated way to tackle event-based programming. Statecharts are especially useful for programming event-response applications such as intricate user interfaces and advanced state machines used to implement dynamic system controllers, machine control logic, and digital communications protocols. By combining the LabVIEW Statechart Module with simulation loops, you can implement hybrid discrete-event and discrete/continuous time systems all in one single environment.

Figure 4. Simulation Loop with Integrated Statechart

Conclusion

With the LabVIEW Control Design and Simulation Module, you can decrease time from development to deployment by closing the gap between control design and controller implementation.

Learn more about LabVIEW Control Design and Simulation Module in the following link

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