Pretty cool arm control. We went from joysticks to this ‘arm’ which is attached to a human arm…to control the bot arm…much more intuitive to control. The human ‘arm’ has pots on the wrist (controls up/down wrist), elbow and two on the shoulder: one to control the upper arm and the other to control turret rotation. The ‘arm’ has a joystick handle for the hand to grasp and use buttons to enable/disable the arm and also to enable/disable turret rotation. In addition, joystick is available ‘just in case’. There is a cable that runs from the back of the vest to the OI and splits to two of the game ports for button and pot input and also LED status lights implemented on the joystick handle.
We saw several examples of arm control in the regionals using the same concept both laying flat on plexiglass as well as standing up. We went the next step and just attached it to a human.
Wow.
Our team has the same basic arm design as you, with an azimuth turet, a shoulder, an elbow, and a wrist. (Our design picks up the tubes with 3 fingers)
We that too, and we built a prototype but we went with a joystick in the end because we didn’t have time.
Great job!
The PID control had already been written and tweaked by a student before we took on the human ‘arm’ control concept. The turret control was tweaked several times to reduce the amount of human arm movement: a lookup table was created to remove the large ‘dead band’ due to the victors and overcoming inertia/friction…we associated slight arm movement to higher power values and then ramped it up in increments of 2, then 3, then 5.
The larger headache we had were pots slipping on the shafts. We went through several iterations of fastening and ended up with vinyl tubing and baling wire to allow for flexibility between the shaft and the pot. On the arm we used set screws to set the pot shaft in to position.
Unfortunately we did not win any FIRST awards for this as the proof of ‘goodness’ is in the use of the control on the field. The drive team did not have much practice time with the arm before WMR. At BMR we were mainly (only?) a defensive bot.
That being said we were recognized by several teams at WMR with team-provided awards for the innovative arm design. So…yes…we did receive the recognition of our peers…which is very appreciated.
Your arm controler was absolutely amazing! Our pit was right in front of the practice field at West Michigan. I could not help but wonder what would happen to the robot if your operator had to sneeze! We use a pot on our arm with a really slick coupling. It has a a shaft collar on both ends and a spiral of the same material with maybe a dozen spirals like a spring between them. Since we started using this we have not blown a pot and have not have any problems with the feedback (knock on wood). The coupling also gives flexability between the shaft and pot. All I know about them is that we purchased them from McMaster for about $30 a piece and that they can be found under ‘shaft collars.’ They look like they are made of black plastic.
OMG. I was actually thinking about using my own arm to control our robot’s arm this year but I didn’t think of it till the plane ride home after our last regional. The only problem with that though was we have a third moving joint on our arm which moves back and forth kind of and we didn’t think we could figure out that part out.
I just checked the team list for championship and I so wish I saw you guys on that list. This is one innovative controller I have seen through the whole time I have been involved with FIRST. Congratulations, and I hope to see you at some offseason events.
**Autonomous: ** The vest/arm hang on the OI board. At the end of autonomous the operator walks up, puts the vest over hear head (and safety glasses) and slides her arm in to the supports…the velcros the straps. In the meantime the driver starts to move the bot.
Sneezing or something: A concern we had was getting distracted and turning to talk to someone, etc. Just like driving a car, and sneezing, care must be taken. The arm disable button could be pressed on the onset of the sneeze…if the operator had their wits about them. If not…then the robot arm would move the same way the human arm did durign the sneeze…and then would move to the position the human arm was in ‘after’ the sneeze.
In our pit area and the practice area we set up orange cones around our work cell/area and warned people to not enter the area. We also called ‘clear’ when the arm was enabled…and completely cleared the area when the turret was to be used.
If she sneezes it autonomously hangs 8 ringers… in the code we call it ‘A.Baker’. Getting the accelerometer and gyro to set-up to detect that took hours. Unfortunately, now she only has a raspy cough.
Seriously though, there is an enable/disable button on the handle in her hand as well as buttons to rotate the wrist CW/CCW. FYI… the $60 bionic arm also controls turret rotation.
More info… (Mark and I are playing off each other’s posts)…
LEDs on the joystick handle attached to the arm:
Red only (arm disabled)
Green only (arm enabled)
Red and Green (arm enabled and turret enabled)
Buttons:
enable/disable arm
enable/disable turret
rotate wrist left
rotate wrist right
We looked at using the tophat to control the wrist…but the position of the tophat was not ergonomically ‘good’…and we ran out of time to do more work on the arm to make it usable.
