In the end, we established close-to real-time control of the robot that is intuitive, versatile, and can record movements for later playback.
Force Sensing Tool
We decided to purchase the SpaceMouse Compact by 3DConnexion which is a wired six-dimensional space mouse. This mouse has a high degree of accuracy and sensitivity with a translational tracking of 250 inc/mm and rotational tracking of 170 inc/degree. With respect to the speed at which the mouse can record movement, its maximum rate of increment is 13,500 inc/sec.
Labview – Control Interface
The purpose of the LabVIEW programs is to establish communication between the space mouse (user) and the robot using a series of programs and subprograms. An overall program flow chart is shown above. LabView is also responsible for interpenetrating the space mouse input to create a movement vector that will be sent to the FANUC robot. These position values are sent to the FANUC via register values.
Scaled Filtered Variable Magnitude Directional Control
This was the final control system that we created to process in inputs from the space mouse. This system operates off of the changes in the values of the space mouse every third of a second. Each direction or rotation is scaled down to move between 0 and 10 millimeters, or 0 and 1 degrees respectively. Our final controller also has a low pass filter that analyzes the final movement values we are passing and zeros out values of inconsequential nature. Additionally, if the right button of the space mouse is depressed, the scale of movement is dramatically decreased to between 0 and 1 millimeter in the x, y and z directions and between 0 and 0.1 degrees.
Effective Control of the FANUC Robot
The FANUC Robot runs a program which takes the register value sent to the robot from the LabVIEW code, adds them to the robot’s current position, and transfers these updated values into a position register which the robot then moves to.
There are two main safety features of the FANUC Robot. First, it is located within a steel and plastic enclosure with a single door. There is a sensor on the door frame that stops all movement if the door is opened.
Secondly, the FANUC Robot has Dual Check Safety (DCS) features. This allows for a “safe space” where the robot is free to move. Once it goes outside of the designated space, it faults out and will not allow the user to move the robot further outside of the space.