Since its first prototype built in August 1999, RHex robots have gone through several design iterations and improvements. This page summarizes key aspects of each of these design iterations and provides the related relevant links.
The version numbers we adopt below are all based on the incorporated features. Note that due to the fact that there are several groups working on different aspects of RHex, possibly on different machines, some of the actual robots may not be fully compatible with the features that a particular RHex version requires.
RHex
1.0
RHex 1.0 introduces an improved frame, half-circle legs, new electronics and wireless capabilities
RHex
0.2
RHex 0.2 incorporates the mechanical improvements of RHex 0.1 and introduces inertial sensing hardware.
- Sensing
- Two dual-axis accelerometers for measuring body acceleration in three dimensions
- Three rate gyros to obtain body angular velocity
RHex
0.1
This version of RHex builds on top of RHex 0.0 with many mechanical improvements. All the computational architecture, controllers, actuation and sensing as well as the electronics remain the same.
- Mechanical specifications
- Body dimensions: 0.47x0.20x0.12 m, ground clearance: 0.13m
- Leg design: More compliant, 4 bar linkage legs. Length: 0.17m
- Total weight: ? g
RHex
0.0
RHex 0.0 is the original prototype RHex (also known as RP-0). The following list is a summary of RHex 0.0 features.Details on RHex 0.0 design can be found here (password required).
- Mechanical specifications
- Body dimensions: 0.53x0.20x0.15 m, ground clearance: 0.10m
- Leg design: Heat shaped Delrin rods with soft feet. Length: 0.175 m
- Total weight: 7247 g
- Electrical characteristics
- Power source: 2 * 2.2 Ah @ 12 V lead acid batteries. Autonomous endurance: 48 mins standby, 8 mins running
- Power circuitry: Double-ended filtered PWM motor drives with 15A continuous max current. Voltage control mode.
- Actuation and sensing
- Six 20W DC brushed motors with 33:1 gearheads. Maximum output torque per leg: 3.614 Nm (50% eff.)
- Six optical encoders coupled to the motor shafts
- Six channels of remote control input
- Battery current and voltage measurement.
- Control software
- DOS operating system on a 486DX100 CPU
- Local PD control loop for each leg closed at 1KHz in software
- All leg coordination and behaviors implemented onboard, with directional commands from the R/C unit.
- Behaviors
- Basic alternating tripod gait.
- Walking forward and backward with differential turning
- Turning in place
- Walking upside down (no automatic detection)
- Basic alternating tripod gait.