Mechanical Bull

 This project was a good refresher in electrical component design. I remember that this was a mechanical bull that was donated to the University Rodeo Club without a controller. It was pointed out that this was not a hydraulic driven practice device but driven by motors. Upon further investigation of the bull, I found that the motors were DC motors. 


Now, my background in the electrical field had taught me a lot of things. But I had not come across too many DC motors, this was also before Tesla became popular. I knew that DC motors had almost instant torque and the voltage could be inverted quickly to reverse rotation, which was desirable in this application.

Testing

Before I could even think about ordering parts for a complete controller, I needed to test the equipment. So I ordered the reverse speed drive. I set up a test bench for the drive, then hooked up 240V to the unit and tested each of the motors. Videos of the test are below.

    The Bucking motion of the bull.

 

   The rotation of the bull.                

Parts

After a successful test of the motors, the drive for the bucking motion was ordered it was a variable speed drive.  

It was also decided that the budget for the controller would be under $500. The cost was taken up by the drives, more than half of the project costs. the rest would be off the shelf hardware from Home Depot. This included the enclosure, receptacles, wire, terminal strip, and terminal hardware. I also ordered some momentary switches, a 240V contactor, and a safety stop switch. 

Planning

I needed to come up with a schematic for troubleshooting proposes in the future. One of the techniques would be to check voltages at various testing points, so I had to localize a location to test voltages to each of the components. Voltages could be verified to this point without expensive components coming into any danger.

Fabrication

Next, I started by mounting the drives in the enclosure so that I could design component placement of the smaller parts.


I then started making terminations to the terminals of the drives then to the strip using the forks. This process took a while because I wanted to make sure that my wiring would look great and would also help in the troubleshooting process if the need ever arises.


Holes were drilled for the receptacles to connect to the enclosure, the boxes housing the receptacles were mounted onto the enclosure as well. The motors were wired to plugs that would connect to twist lock receptacles. The incoming 240V was hardwired to the terminal block so that it could be distributed to the two drives. 


In the above pictures, the drives and connected to the potentiometer. I also have the emergency stop button connected to the contactor relay. 

In Motion

When power is applied to the controller, it first terminates to the strip, goes to the contactor. I also decided that it would be a single throw double pole, so that the incoming line could be split at the contactor terminal and the output side of the contactor terminals would go to separate drives. It was also determined that amperage would have to be stable on each leg of the contactor. 

The user would push a green momentary switch, that activated the contactor. provided power for the drives, and the drives would be controlled with the potentiometers. If an emergency situation arose, the user could cut power off by activating the emergency off switch that would deactivated the contactor. Then the receptacles could also be disconnected to make sure power was fully off.

Below: the creator (Hansen) with the bull controller.

Testing

After rigorous testing with dummies (sacks of sand and gravel) we were confident to try human candidates with the NTU Rode Club. Below is a small collection of the many tests of the initial power up.




I feel that this project has help trained many students in a controlled environment, preventing them from getting seriously injured at an event by showing them expectations of riding an animal. 

According to the sponsor, the was a great help and later that school year helped students become high ranking riders in their categories (Bull riding, saddle bronc, and bareback riding).


Comments

Post a Comment

Popular posts from this blog

Joule Thief

Image
A joule thief is essentially a way to "squeeze" as much power out of a "dead" battery. Meaning that batteries that were outputting low voltages could be used in light load applications. In theory, the system is a oscillating voltage booster. Using the transistor to switch the LED on and off at a high frequency, that the human eye cannot detect the on and off switching. In this project, I was in a electronics class learning about components on a circuit board, transformers, toroids, and at the time transistors. I had found an old circuit board laying around the lab from an older computer.  Parts I started desoldering some of the components that were familiar: a toroid, a 2N3904 transistor, resistors, and an LED.  I also found strips of solid wire at 2 foot lengths.  Soldering material was available at our lab. A power supply was also available. Planning Although I had this mapped out in my mind, I made a diagram of the circuit to make sure that if I had any other dis...
Read more

Augmented Reality (AR) Proof of Concept (POC)

Image
 This is a short summary of the research and design aspect of prototyping apps for possible use in military programs. Although the following was a culmination of weeks of research on my own time, the applications of AR are still countless. The Project Many projects start with the, "Why", and "How". So the reason I wanted to build this project was for my own gratification, to understand some of the concepts of AR development and to use Unity 3D. I would have liked to see our soldiers or maybe even regular people, to check on situations in their surroundings by interpreting data and stimuli into a very condensed but readable display. I know that I am not the only one to think of "Iron Man" when it comes to situational awareness displays. But what if we were wearing VR googles with cameras? Could we use those cameras to take in information that we were otherwise blind to? The ability to use a VR headset and pay attention to the world would be pretty awesome. ...
Read more