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Command Velocity

Mechaware API Documentation > Input

Overview

Overview

Description

The Command Velocity block is an Input block that is a source for Command Velocity data. The output from the Command Velocity block is the Axis Command Velocity value, updated as determined by the Evaluate Block.

The Command Acceleration block is often used to generate an Acceleration Feed Forward.

Example

In the following example, the Command Velocity block is used and sent into a Gain block, this Gain block is often called Kvff – the Velocity Feed Forward Gain. This gain helps account for the mass or inertia of a mechanical system.


The following parameters are used to configure this block at load time:

 
Axis Number

The number of the axis which is the source of the velocity data. This number may be absolute or linked to the Model Number.

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) or background. 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

cmdVelo1

The sim (opt) input is an input which only relates to simulation.

Note: This input is only used when simulating within Simulink and is ignored when the model is downloaded to a controller.

By supplying a value from a Simulink source or a trajectory generator that passes the value through the model, will allow you to see how the system responds given a Command Velocity. Additionally, allows you to to generate a torque command with a PIV system or BiQuad Block and simulate Velocity Feed Forwards or Friction Feed forwards.

The Output of the Command Velocity block is the Axis Command Velocity value. This block has no inputs.

The Axis Number of the axis providing the velocity data is determined by the Axis Number parameter. This number can be absolute or linked to the model number.

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:

cmdVelo2

 

C++ API

TCVELBlock

Declaration

Public Method

  
class TCVELBlock: public virtual Block
{
public:
	// User accessible coefficients
};
 

Required Header: mechaware.h

Description

The Command Velocity block is used to connect the inputs of a model

Methods

Block Methods

See Also

Memory
 Torque Output
Noise Generator MemoryOut
Actual Position Memory Out User Buffer
Command Position Scope
Position Error Feedback
Memory User Buffer Reset Status
Command Acceleration Test In
Command Velocity Test Out

 

 
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