Types of MechaWare Blocks
There are four types of MechaWare blocks: I/O, Computational,
Data File, and Advanced.
Input/Output Blocks
Input / Output blocks are used to pass data to and from
the Filter Objects. The filter algorithm can read data from any Axis Object
and can write data to any Motor Object. The ability to access multiple
data locations with the Input/Output blocks makes the design of MIMO (multi
Input, multi Output) control algorithms possible. I/O blocks require a
specific format for data entry, the format is the block tag followed by
the desired axis number.
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Input/Output Blocks
|
|
Block
|
Type
|
Tag
|
| Actual Position |
Input |
ACTUAL |
| Axis |
Input |
AXIS |
| Command Position |
Input |
COMMAND |
| Error |
Input |
ERROR |
| Constant |
Input |
CONSTANT |
| TC Vel |
Input |
AXIS |
| TC Acc |
Input |
AXIS |
| Noise |
Input |
NOISE |
| Scope |
Output |
SCOPE |
| Output |
Output |
OUTPUT |
In the example above, the block uses the
actual position from Axis 3 as feedback.
Computation Blocks
Computational blocks support basic mathematical operations,
biquad filters, and matrix computation. Each block will generate a single
output from a single or multiple inputs, depending on the block's functionality.
|
Computation Blocks
|
|
Block
|
Tag |
Use
|
Parameters
|
| Gain |
GAIN |
Constant gain |
K |
| Matrix Gain |
MATRIXGAIN |
Vector product with sum |
Length, Coeff[] |
| Differentiator |
DIFF |
Derivative with smoothing |
Ksm |
| Integrator |
PID |
Integration |
Ki |
| PID |
PID |
Proportional, Integral, Derivative |
Kp, Ki, Kd, Imax, Drate |
| PIV |
PIV |
Proportional, Integral, Velocity |
|
| Feedforward |
FF |
Four types of feedforward |
Kaff, Kvff, Kpff, Kfff |
| BiQuad |
BIQ5 |
Double precision observer |
Length, Coeff[] |
| Sp_BiQuad |
BIQ |
Single precision observer |
Length, Coeff[] |
| Observer |
OBS2 |
Double precision observer |
Length, Coeff[] |
| Observer |
OBS |
Single precision observer |
Length, Coeff[] |
| Clip |
CLIP |
Clip to limits |
Limit, Offset |
| Sum |
SUM |
Multi-input sum |
nSum, Coeff[] |
| Multiplication |
MULT |
Multi-input product |
nMult |
| Division |
DIV |
Multi-input quotient |
nDiv |
| Sine |
SIN |
Sine |
None |
| Cosine |
COS |
Cosine |
None |
Biquad/Observer Block Data File Format
Biquad and Observers Blocks are defined in two ways. In the MATLAB workspace they are defined by a MechaWare biquad/observer structure. This structure is then used to create biquad and observer text files that are used to load block parameters to the ZMP or XMP controller.
The observer and the biquad blocks are defined in the discrete time domain. Mechaware structures include z-transform and difference equation descriptions of the blocks.
Biquad Structures
Z Domain
Difference Equations
Biquad Structure |
Element |
Description |
| OBS.b |
B(z): transfer function numerator |
| OBS.a |
A(z): transfer function denominator |
| OBS.A |
State transition matrix |
| OBS.B |
Input state matrix |
| OBS.C |
Output coupling matrix |
| OBS.D |
Input to Output coupling matrix |
| OBS.Ts |
Sample Rate |
| OBS.sys |
Matlab LTI object |
Observer Structures
Z Domain
Difference Equations
Observer Structure |
Element |
Description |
| OBS.b1 |
B(z): ufb(z)/u(z) numerator |
| OBS.a1 |
A(z): ufb(z)/u(z) denominator |
| OBS.b2 |
B(z): ufb(z)/ymeas(z) numerator |
| OBS.a2 |
A(z): ufb(z)/ymeas(z) denominator |
| OBS.A |
State transition matrix |
| OBS.B |
Input state matrix |
| OBS.C |
Output coupling matrix |
| OBS.D |
Input to Output coupling matrix |
| OBS.Ts |
Sample Rate |
| OBS.sys |
Matlab LTI object |
Advanced Blocks (currently
not supported)
In the future, complex controls functions will be incorporated
into MechaWare blocks.
Examples:
Scara Robot Block
Gearing and Camming Blocks
2 Dimensional Look-up Tables
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