8. Phantom Robot Connector
8.3 Using the Phantom Robot Connector
0.3 0.305 0.31 0.315 0.32 0.325
Simulation of the Effect of the Discrete Filter Implemented in the PRC
Time / (s)
Force / (N
)
Figure 8.1 Shows a force signal and its filtered version. The data used in this figure has been gathered from the actual force sensor in Section 3.3. However, the filter is simulated in Matlab under the assumptions that the force signal has a frequency of 250 Hz and that the filtered signal has a frequency of 1000 Hz.
By choosing the parameters b1, a1 and a2 such that equation 1 = 1−ab11−a2
holds and that the poles of the filter is inside the unit circle, y[k] will go towards
u[k] = u if u is a constant. The discrete filter equation and the corresponding
poles can be seen in Equation 8.2 and 8.3 respectively.
y[k] = b1u[k] + a1y[k − 1] + a2y[k − 2] (8.2)
z = a1 2 ± s a2 1 4 + a2 (8.3)
The filter used in Phantom Robot Connector has the parameters a1= 0.5, a2 = 0.3 and b1 = 0.2. The poles are z = {0.8521, −0.3521} and 1−ab11−a2 = 1
which proves that the filter is stable and that y[k] → u[k], k → ∞. A force signal filtered by the proposed filter can be seen in Figure 8.1.
8.3 Using the Phantom Robot Connector
When the Phantom Robot Connector starts, a console will appear and the user will be given three options to choose between, see Figure 8.2. The first option is to start running a virtual robot equipped with a tool that is a virtual replica of the force sensor construction in Figure 3.5. The second option is to run the program with the same virtual robot but without the tool. Both these options make the program run without any communication with the real robot. In these cases, the Phantom Robot Connector can therefore be seen as a pure virtual robot that will demonstrate how the real robot would have
Chapter 8. Phantom Robot Connector
Figure 8.2 The Phantom Robot Connector awaits the user’s choice at startup.
behaved, had it been connected. The third option in the console is to connect to the IRB140B over a network. As soon as a connection is established the main program will start. The force sensor described earlier is assumed to be attached to the IRB140B in option number three.
There are a number of different keys the user can press to control the run-time behavior of the Phantom Robot Connector. A full list is found in Appendix B. One of the things the user can activate is the painting mode, by pressing [D]. If this is activated the program will draw small blue surfaces perpendicular to the sensed force at the correct location in the 3D-space. This will work for both virtual objects in the phantom2graphic mode and for real world objects in the phantom2robot mode. If the user presses [C] all the paint is erased. There are also a lot of small visual settings that the user can activate or deactivate.
The view perspective of the virtual robot can be changed by moving around on a sphere surrounding the robot. This is done by pressing the left and right arrow keys to move around a horizontal circle and by pressing the up and down arrow keys to move around a vertical circle. Pressing the page up and page down keys will change the radius of the sphere causing the view perspective to zoom in or out. By pushing key [P], [R], [H] the program will change mode to phantom2graphic, robot2graphic or phantom2robot respectively. To change the mapping setting between free orientation and fix orientation of the TCP frame the [O] key is pushed. All settings that are activated will be highlighted in the color green.
In the phantom2graphic mode some other settings will be revealed on the screen. These are the No Obstacle, Wall and the Sphere and they are activated by pressing the [N], [W] or [S] keys respectively. As the names imply they activate the virtual wall, the virtual sphere or in the first case neither of them. The setting that is activated will as before be highlighted in green.
Some settings can only be made in a predetermined order. This is in order to avoid a strange behavior from the program. For example, the virtual ob- stacles are only available in the phantom2graphic mode. They will disappear when changing mode. The allowed combinations can be seen in figure 8.3.
On the right side of the screen the real robot angles are printed. But if the mode is set to phantom2graphic it will only show the simulated robot angles that the graphical robot are using. Below the Robot angles the force signal is expressed. Also for the force it holds that it is not the real force signal that is represented in the phantom2graphic mode. In the other modes it is the received force signal that is printed on the screen.
8.3 Using the Phantom Robot Connector
P
R
H
O
W
S
N
Z
robot2graphics phantom2robot phantom2graphics Wall Sphere No obstacle Hide/View obstacle Free orientationFigure 8.3 Depending on which mode is active, different actions can be taken.
For the full list, see Appendix B.
[ESC] will exit the program. The force sensor attached to the robot can be reset by pressing [0].