Dennis, the Telepresence Robot
The finished "robot", a treaded platform carrying a Mac laptop and iSight camera.
The robot base is a modified radio-control tank.
Access Grid Retreat, San Francisco, USA
Dennis outside one of the conference rooms. "Everybody loves a robot".
Dennis meets Arthur - View Movie (2.7MB Quicktime)
Built on the treaded chassis of a cheap remote-control tank purchased on eBay, Dennis is a prototype telepresence "robot" constructed and programmed in the short span of two weeks.
The impetus was a planned demonstration of our AGDeviceControl software at the 2005 Access Grid Retreat in San Francisco, USA. AGDeviceControl is an extensible framework for the remote control of pan-tilt-zoom cameras, projectors and custom instruments in the Access Grid. To show the flexibility of the system, and because "everyone loves a robot", we decided to build a steerable mobile Access Grid node - Dennis.
Stripping down the $50 tank to the bare chassis, we tossed away the cheap radio-control circuitry in favour of the laptop's native 802.11g wireless. Two electronic speed controllers with servo PWM inputs were connected to the left and right-tread DC motors. Interfacing these to the laptop was a Phidgets USB quad-servo controller board. The wiring was done by ANU Electronics Technician Dennis Gibson (the robot's namesake), who both reverse-engineered the original tank's electronics and then wired up the Phidgets controller allowing Darran Edmundson to focus on programming.
The chassis completed, a removable platform covered with a rubber non-slip mat was constructed to carry the laptop, a 15" Powerbook kindly loaned to us by Apple Australia. To allow the remote operator to steer the robot and interact with conference participants, an Apple iSight camera was mounted on a tiltable platform, the up-down position controlled via a third servo motor connected to the Phidget board.
Hardware list:
- Treaded chassis from cheap remote-control tank, $50
- iSight firewire camera, loaned by Apple Australia
- 12" Powerbook, loaned by Apple Australia
- 2 electronic speed controllers, $100
- Camera tilt servo, control rod, servo horn and hinges, $60
- Phidget USB quad-servo controller, $75
- Wood platform, camera post and non-slip mat, $35
- Spare battery and charger, $100
As mentioned, Dennis was created to demonstrate our AGDeviceControl software. An extension module was written that exposed a clean programming interface with commands like "SpinLeft", "MoveForward", "SteerLeft", etc. Internally, the robot implemented a finite-state-machine that hides the complicated details of talking to the phidget controller. On top of this programming interface, an intuitive graphical interface was constructed that would allow Access Grid participants worldwide to control the robot.
As part of the conference, Microsoft donated three XBox game systems as prizes for people demonstrating new and inovative Access Grid software. Dennis (the robot) won an XBox, even though he was caught sneaking up on the judging panel during their deliberations.
Lessons Learned:
- Low robot has a rodent-like feel, both in how humans interact with it and the perspective from the remote operator. Expect different reactions from something taller (but not too tall to be imposing to children).
- Interface responds differently depending on terrain texture. Moves easily on smooth floor, requires greater mouse travel on carpet for equivalent motion. This should be handled transparently.
- Consider both wide-angle lense and ability to look around easily while travelling.
- Need failsafes, no motion without continuing signal from base.
- Need a means of interacting like an arm, pincers, etc.
Copyright EDM STUDIO INC. 2006-2007