Overview

Description

The Differentiator block calculates smoothed derivative of the input.

This block is commonly used to determine the Velocity from Position, which can also be used to feed a Derivative Gain. Also you can derive Actual Acceleration from placing a Differentiator on the Actual Velocity.

The block is calculated at the update rate, determined by the Evaluate Block.

Example

This example shows how to construct a PID Filter from scratch, the Differentiator is placed on the Position Error, then fed into a Gain (the gain corresponds to Kd in a standard PID block).

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The following parameters are used to configure this block:

Ksm	Smoothing parameter. 0 = no smoothing.
Evaluate Block	This block allows you to specify whether the block executes Every Sample, Every Other Sample (Odd or Even), or Every Fourth Sample (and specify the First, Second, Third, or Fourth). This provides greater flexibility in controlling the execution of a model and to preserve performance for other areas of motion control.
User Defined Block Priority	When selected, allows you to enter a Priority Code to modify Execution Ordering of this block. For more information, see Block Execution Order and User Defined Block Priority.
Priority	For an explanation of how the Priority field is used by the MechaWare Model Downloader, see Block Execution Order and User Defined Block Priority.
User Data 0	Application-specific data. See User Data Storage.
User Data 1	Application-specific data. See User Data Storage.

Matlab/Simulink

Simulink Interface

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The Output of a Differentiator block is the derivative of the input. The derivative is passed through a smoothing filter.

The block has two user data fields (User Data 0, User Data 1) to store application-specific data for convenient storage and retrieval. See User Data Storage for details.

The block's update schedule is determined by the Evaluate Block. The following Parameter Dialog Box can be opened by double-clicking on the block in a Simulink Model:

C++ API

DIFFBlock

Declaration

Public Method

	class DIFFBlock: public virtual Block { public: // User accessible coefficients double Ksm; };
	Required Header: mechaware.h

Description

The Differentiator block calculates the smoothed derivative of the input.

long

Ksm

Smoothing parameter. 0 = no smoothing. 1 = infinite smoothing.

Methods

Block Methods