Onboard PC, Heading Correction Gyro | Pioneer 2TM, 3TM specs

ActivMedia Robotics

Onboard PC

Communication between the onboard PC and the H8S microcontroller is RS232 serial through the respective COM1 (Windows) or /dev/ttyS0 (Linux) and internal HOST ports. Set the HostBaud FLASH communication rate to match the PC client-software’s serial port rate.

Beginning with AROS version 1.6, the RI pin 9 on the HOST port initializes to low and goes high when the batteries discharge to below 11 VDC. We use the genpowerd software under Linux to detect that low-power signal and automatically shut down the PC. Windows PCs are a bit more problematic.

The Windows genpowerd-like ups.exe program requires a dedicated serial port and prefers to use the CTS line to indicate low power. Accordingly, we jumper the RI signal of HOST COM1 to the CTS signal pin of the adjacent COM2 port of the onboard PC for the feature. For convenience, the Versalogic VSBC8 PC found onboard most recent Pioneer 2s shares its 20-pin connector on the PC's motherboard with COM1 and COM2. So, to implement Windows ups.exe-enabled low-power shutdown, we jumper pin 8 (COM1 RI) to pin 16 (COM2 CTS) on that VSBC8 serial connector. Use a similar strategy for other implementations; the UPS configuration dialog lets you select COM1-4.

Once the port is wired, start up Windows and, as Administrator, go to the Start:Settings:Control Panel:Power Options dialog and select the UPS tab. Click Select and in the UPS Selection dialog, select COM2 (or other) port, Generic manufacturer, and Custom model. Then click Next.

In the UPS Interface Configuration On: COM2 dialog, check the Power Fail/On Battery and its related Position options. Uncheck to disable the Low Battery and UPS Shutdown options. Then click Finish to save the settings and close the dialog. Click OK or Apply to enable the UPS shutdown programs.

Change a registry value so that the PC shuts down one minute instead of two minutes after low-power notification by the controller: Use regedit and navigate to

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\UPS\Config. Change the ShutdownOnBatteryWait dword value to 1 (from 2).

Use the AROS client maintenance command #250 to test your genpowerd or ups.exe setup. Send the COMshutdown command #250 with an integer argument of 1 to simulate the low battery condition, in which AROS issues warnings first, then disconnects from the client after about a minute and sets the PC-shutdown signal on RI. An argument of 2 forces the computer shutdown signal (RI high); 0 cancels the shutdown/test. Resetting the controller cancels shutdown, too, unless battery power really is very low.

Put the controller into maintenance mode and fix your onboard PC settings if the computer falsely engages genpowerd or ups.exe.

Heading Correction Gyro

With the new rate-gyro accessory, your client software may detect and compensate for robot heading changes that aren't detected by the wheel encoders, such as from slipping wheels. AROS version 1.8 and later supports the gyro via its attachment to the AN6 and AN7 analog-to-digital input ports on the H8S microcontroller.

AROS collects 10-bit (0-1023) gyro rate and 8-bit (0-255) temperature data and will, upon request, send the collected data to a connected client in a new GYROpac (type=0x98) server information packet for processing. Analysis of the gyro data and subsequent