|Heitz Automotive Testing LLC||
The Heitz System 4 consists of a power supply and programmable servo actuators for Steering, Throttle and Brakes, which can operate independently or in combination. Each servo actuator is sufficiently powerful, fast and accurate for any existing or proposed testing protocol.
A compact "Battery/Electronics Box" has up to four plug-in trays for Power, Steer, Brakes, and Throttle.
Each actuator tray has its own CPU and interface connectors for USB, SD card, RS232, and CAN. Each actuator can be controlled independently by external or internal programs, or a program in one tray can control other trays. Steer, throttle and braking can also be controlled directly by analog commands from an external source. The EPROMS of Sprint 3 have been replaced by SD card for direct USB programming, with greatly expanded capabilities.
The Steer, Brake, and Throttle trays differ only in detail. Plug-in modules for CPU, eight-channel A/D, 6 channel D/A, servo amplifier, counters, and isolation amplifier are the same in each tray. For connector interface and front panel inputs and outputs the modules are the same but the connections are different.
Each tray has BNC connectors for relevant input/output signals. Each BNC signal is galvanically isolated to prevent ground loops.
SD Cards / Direct USB Programming
Test programs may reside on removable SD card or in internal flash memory. SD cards may also contain the vehicle identification and configuration and other test information, with write protection that can provide some assurance of program integrity over time as did the old EPROMS. Some organizations prohibit SD cards for reasons of security. In this case the SD card slot can be left open, and programs can be loaded into flash memory using the USB port.
System 4 is designed to be an integral part of an autonomous vehicle control system. The “External” connector on the power supply panel has direct analog commands to the steering throttle and brakes. A USB connector provides additional interface.
The Abort input uses a signal from a radio link from a test observer. Abort causes full braking and dropped throttle. Steer can be programmed for either hold constant or return to straight ahead.