Monitor and Control of an Excavator Robot

The webpage gets a graphical facelift.

The GUI can now take in data from a file, as well as being controlled by the keyboard and mouse. This method will be used to take data from the HC11. The HC11 will write the data to a file, and then the GUI will draw the information from the file.

This post outlines the progress made in the past week, along with the goals for the current week.

Excavator Hardware (Vuk)

The following tasks were completed
• 1) brackets have been installed, and sensors have been epoxied and mounted
• 2) 1 encoder has been re-ordered
• 3)preliminary wiring has been performed (pending approval, it will be made permanent with tie wraps/electrical tape)

Goals for the current week
• 1) make wiring permanent
• 2) get standoffs for driver board and HC11
• 3) start working on powering the whole system autonomously

HC11 (Ryan)

The following tasks were completed
• 1) worked on serial communications
• 2) develop a C++ program for recieving data on the PC as well as an HC11 program to send the data.

Goals for the current week
• 1) integrate the serial communication software and use these programs to read in sensor info
• 2) convert the recieved data to joint angle for the potentiometer
• 3) convert the recieved data to degrees rotated for the encoders

GUI (Alan)

The following tasks were completed
• 1) motion problems for excavator now corrected (problems with disjointed axis of rotation)
• 2) bucket added to model
• 3) code to move stick and boom added
• 4) preliminary environment added
• 5) preliminary development plan for 2D GUI elements
• 6) cardboard acquired for physical environment

Goals for the current week
• 1) continue work on environment
• 2) research OpenGL techniques to develop the 2D GUI elements
• 3) formulate plan for integration with signals being sent from HC11

Progress has been made on actually moving the excavator realistically. Using the ‘w’ key moves the excavator forwards, and using the ’s’ key moves the excavator backwards. The ‘d’ key rotates the excavator clockwise, and the ‘a’ key rotates the excavator counterclockwise. Logic for the rotation and movement is still flawed. Only works for rotation at the beginning and then translation. Problem is associated with the excavator not rotation on it’s own axis, and rotating instead about the origin.

The boom and the stick can now be rotated and translated. The entire boom and stick can be translated in the +x, +y or +z directions with the ‘x’, ‘y’ and ‘z’ keys and in the -x, -y, or -z directions with the ‘X’, ‘Y’ and ‘Z’ keys. The boom can be rotated and when it rotates, it cause the attached stick to rotate as well. The stick can also rotate independently of the boom.

The stick can now be rotated on it’s hinge axis in both the positive and negative direction with the use of the left and right mouse buttons. It can also be translated in the x, y and z directions with the ‘x’, ‘y’, and ‘z’ keys.

This post summarizes the work done on the week beginning November 6 up until November 13

Motorola 68HC12
Ryan has completed the testing of the Motorola 68HC12 and it appears to be functioning properly. A few of the ELEC371 labs were run successfully and the output ports with LEDs were also tested.

Excavator Procurement
Vuk has sent a request to Dr. Greenspan and Dr. Korenberg about the possibility of procuring the excavator by sending it to a third party. The vendor will only ship to the United States, and the cost of procuring the excavator through other sources is much more costly. Our group is awaiting a response from Dr. Greenspan and Dr. Korenberg about the possibility of side-tracking Tech Service’s rule of shipping only to Queen’s.

Wiring Diagram
Vuk has created a preliminary wiring diagram for planning of how the excavator, sensors and boards will be wired together. This wiring diagram will aid in the design and construction of the modified excavator.

Virtual Model
Alan has completed the development of an object class. The object class represents a base class that all other objects will be built upon. From this object class a boom class and a stick class were developed. Currently both of these objects are represented as simple rectangular prisms. Work is currently be done to rotate one object around another in 3D space. The rotation were performed successfully in 2D with two 2D objects.

This post summarizes the work done on the week beginning October 13 up until November 6.

The project webpage is now online @
http://bobbleheadal.com/490project/

Virtual Model
Two 3D objects were created in 3D space, both of which are rectangular
prisms representing the stick and the boom. Both are created as objects as
part of the hierarchy to form the excavator arm. I am currently working on
logic to move the two objects in space rotating around an axis based on a
variable angle.

Excavator Procurement
Vuk has found an American distributor for the 1:12 excavator mentioned last week.
Once ordered it will be shipped to Vuk’s family in the states and either shipped here or brought up November 24. Cost is approximately $142.10.

Budget
A more detailed budget was created of parts we need to purchase now that we know which existing parts are in working order.

Equipment Testing
Ryan and Vuk tested the existing potentiometers, encoders, H-bridges mounted on the PCB and also the voltage regulation. A summary as well as details are given.

Summary:
• Both pots work but 1 can not be detached. Suggest buying 1 replacement and 1 backup.
• 2/3 encoders work correctly with square wave pulses. The 3rd encoder with the soldered ground pin does not produce the desired square wave pulses. Suggest buying 1 new encoder.
• 4 H bridges on PCB all work properly.
• Voltage Regulation on PCB works properly.

Potentiometers were tested by powering one pin with 5V, grounded 1, and reading the voltage level at the other pin with an oscilloscope. Both pots had the voltage accurately vary from 0-5V.
We did have a problem getting the ‘boom’ pot. off the old excavator, and talked to Roy about it. He agreed that it is fastened too tightly to remove without damage to the pot. We have decided to replace 1 potentiometer and also get 1 spare.

Encoders were tested by connected 1 pin to a 5V DC source, 1 to ground, and the remaining 2 to the oscilloscope. When the encoder knob was turned, square wave signal were outputted to the oscilloscope. The 2 outputs were out of phase by 45 deg and depending on cw or ccw rotation, one wave either lagged or lead the other. 2 encoders produced this desired square wave. One which was used last year and one which was not. The other which was used last year did not produce the square wave.

Voltage Regulation was tested by applying 12V DC to the PCB board and measuring the output of the voltage regulation. The output was 5V which is correct. This 5V would be used to power the HC12 and the wireless transmitters.

H bridges were tested by powering the board with 12V and applying varying voltage to the input pins while measuring the voltage at the motor output pins. All 4 were correctly amplifying the voltage.

The Wordpress Weblog and the Wikipedia for our ELEC 490 project is now online. A website will be set up in the near future to link to these two resources. The Weblog will contain a running diary of the events that take place during the development of this project. The Wikipedia will be a constantly editted resource that will describe the project.