Jackbot

Stuff that's good to know or useful for development. We need to do testing to determine these.

Steering Torque - We measured this by putting the long arm on the servo, connecting the pull scale to the end of the arm, and trying to turn the servo while holding the scale. With our previous setup, we read 6 newtons. The best we were able to get with a stamp program that just reads serial data and outputs PWM is 10N. After measuring this, we decided to add an IC (FT639) which we give a duty cycle via a serial packet and it constantly outputs the appropriate PWM. We could not get the dedicated servo IC to work so we connected the steering servo to the pid2, an AVR microcontroller, so that it sends a continous control signal on the PWM output pin. After remeasuring the torque, we found that we consistently get 11-12 newtons and it can now steer to a new location white idle.

Steering Speed - Time it takes from when we issue a steering command to when the wheels stop moving. This is related to the last one. It's probably more directly useful. We should probably measure this with the load of the robot, on pavement and grass and maybe other surfaces, and both while stopped and while moving

FPS we can process - On X61, currently runs around 40 fps with an image as the source and with a little bit of enlargement going on. With the camera and some more noisy images, it dropped to around 20 fps at worst. It's much slower on the original laptop. with the camera, it visibly freezes periodically. This might be due to garbage collection. These numbers are the current state; we're actively working on this code and they're likely to change.

Reflex Time - Time from when what the camera sees changes to when the motors react.

The following table is old. There are some updated measurements in a spreadsheet in our docs directory.