Prototype #1 - Test Plan

Tasks

See Prototype Definitions Page for more info (some content pulled from this page)


Main elements to test (In order):

  1. Speed and acceleration :
    1. Find the ideal joint speeds and accelerations for each joint
  2. Test workspace (no load):
    1. Determine arm mobility
    2. Find the arm positions we are likely to see in the field
    3. Assess accuracy and repeatability of the arm (not mandatory)
  3. Test the torque at each joint (with and without load):
    1. Measure the torque at anticipated joint speeds, accelerations and workspace extremes 


Torque/Speed:

  • Measure torque at each joint (During assembly to ensure roughly correct torque is provided)
  • Measure max torque at each joint
  • Determine a more suitable safety factor based on recorded torque
  • Determine refined linkage lengths (if applicable)
  • Determine approximate ideal RPM for each joint
  • Time Permitting - Data set of joint torques (on average) for all expected arm calcs

Competition Tasks:

Retrieval and Delivery

  • Lifting Payload (5kg payload, rope tow) 
  • Pick something off the ground (5 cm diameter) → Screw driver?
  • Pull an object by a rope

Equipment Servicing 

  • Lift from handle (10cm long, 5cm diameter)
  • Open a drawer → There's one for testing in the bay already
  • Flip a switch → I think there's one for testing in the bay already
  • Turn a knob → I think there's one for testing in the bay already
  • Use of Allen key
  • Use a keyboard → We have one in the bay already and this would be a good opportunity to test the precision of the arm
  • Operate joystick 
  • Insert USB type A into slot

Deliverables

  • Max Torque for each joint (with load)
  • Refined safety factor
  • Refined linkage lengths
  • Ideal RPMs for each joint
  • Idea accelerations for each joint
  • Refined workspace
  • Weight (Is this relevant? Will the change in components make this obsolete?) 

Procedures

3. Measuring Torque

Each step is done twice for each joint (with and without load)

3.1 Measure Power - Voltage

  1. Plug black wire into ground on multimeter
  2. Plug red wire into volts on multimeter
  3. Turn dial on voltmeter so that it is referring to appropriate voltage measurement
    1. V is DC voltage
    2. V with the squiggle is AC voltage (for lack of a better turn)
  1. Put multimeter in parallel with motor/power supply

3.2 Measure Power - Current

  1. Plug in black wire into ground on multimeter
  2. Plug red wire into amps on multimeter
  3. Turn dial so it is on the Amperage measurement
  4. Put multimeter in series with motor/power supply

3.3 Measure Speed - Encoder

  1. Record RPMs from encoders

3.4 Calculate Torque

  1. Calculate torque using the following equations

2. Record here


Interesting Method

Came across this video and was curious. Isn't really a viable method for us

See method here