The heart of NavDrive is a MPC555 PowerPC™ processor.

• Floating point
• Socketed
• 448 KBytes on chip EEPROM
• Intelligent IO subsystems
• 2 MByte of synchronous burst RAM with no wait states
• Mode selector switch with 4 inputs
• Dual binary rotary switches
• External Reset
• Three status LEDs

NavDrive provides an extensive interface for controlling two motors using external amplifiers.

The following features are provides by the motor interface:

• Interface for two encoders with index pulses TTL or RS-485
• Amplifier setpoints using 16 bit D/A, step direction, or PWM
• Six analog inputs for current, voltage, and temperature sensing
• Six isolated digital inputs for limit / home sensing
• Two watch dog enabled digital outputs for amplifier enable
• Two watch dog enabled digital outputs for power relays
• All analog IO are conditioned with instrumentation amps

NavDrive's Inertial Subsystem consists of a three axis gyroscope and accelerometer.

Specs:

• Uses three Analog Devices ADXRS300 MEMS Gyros
• Angular velocity digitized by three differential 16 bit A/Ds
• Gyroscope bandwidth set at 10Hz
• Temperature outputs digitized by 10 bit A/Ds
• Uses three Analog Devices ADXL202E MEMS Accelerometers
• Accelerometer bandwidth set at 20Hz
• Acceleration digitized using 16 bit PWM counters.

NavDrive creates all the power supply voltages it needs using a single 12V input. It can also supply power to external devices such as encoders, radio modems and GPS.

Power Supply Specs:

• Input 24V to 8V at 4.2 Watts or 350mA at 12V
• Reverse polarity and ESD protected
• Remote power on signal and CPU controlled shutdown
• Power supply voltage measurement
• Battery backup for CPU and RAM keep alive power
• Extra high voltage sense input for amplifier power

The Ultrasonic Interface consists of a driver and receiver section for four transducers.

Driver and Receiver Specs:

• Capable of driving piezo transducers at 120V p-p
• Impedance tunable to match transducer
• Up to 45KHzUses using the MPC555 TPU to generate output burst
• Nonlinear impedance to accommodate single transmitter/ receivers
• Tunable high gain amplifier and bandpass filter
• Uses the MPC555's TPU to track four echoes for each sensor
• Advanced dynamic thresholding for short and long distances

Navdrive has two RS-232 serial ports and one CAN bus port.

One of the RS-232 ports can be configured with TTL drivers for interfacing with various GPS modules.

Additionally switched power supply pins are provided so a GPS and radio modem can be powered off when not in use. This power supply can be configured to use the on-board 5V supply or use the external (12V) supply to the board.

The CAN bus is ideal for using NavDrive as part of a larger control system.

NavDrive incorporates a three axis compass using Honeywell's HMC1001 and HMC1002 magnetic sensors.

Specifications for the Compass

• ±2 Gauss maximum range
• Digitalization using 10 bit A/D
• Software controlled 3A Set / Reset pulse

NavDrive is a system of hardware and software that can control a tracked or steered mobile robot. NavDrive hardware consists of a complete set of IOs for control of two servo axis, electronics for ultrasonic ranging, GPS interface, gyros, compasses, accelerometers, power supplies, and processor power to take advantage of the sensors. NavDrive can be part of a larger control system or receive direct commands using CAN bus, RS-232, or the 5 channel PWM input for off-the-shelf radio controls.

You can buy separate processors, sensors, and power supplies, but it will cost you more... and think of all wiring.

We also have the software. to make it all work together.

Please use the picture of the board on the left to see information about each section.