Version 2
Topview of the current circuit
| Index | description |
|---|---|
| A | RISC Microcontroller ATmega8 (16MHz) |
| B | RISC Microcontroller AT90S4433 (8MHz) |
| C | Comparator LM339 |
| D | Accelerometers (SMD) ADXL202 |
| E | RS232 interface converter |
| F | 2, 5V-switching regulators 78SR105VC |
ATmega8 (16MHz, Master): This controller replaced the AT8535 because it can be driven
at 16MHz, for a better servo control. An additional operation is the communication with
the Slave-µC via the SPI-Interface.
AT90S4433 (8MHz, Slave): This µC is used to realise the Torque-Feedback. The prepared
PWM-Signal from the servomotors is beeing processed and this data gets transfered to
the Master-µC via the SPI-Interface.
LM339: These comparators prepare the fuzzy PWM-Signal from the servomotors to a
clear digital signal that can be processed by the Slave-µC. A rough overview is given
in the chart below.
TFB Measurement
The given example is valid for the used Sanwa-Servos. For the S-71 the REF-Voltage has to be connected to the noninverting and the motor signals to the inverting inputs of the comparators. The PWM Output-Signal for the Slave-µC is independent of the torque direction, because the open collector outputs of the comparators realise a wired OR-Gate. So the Slave-µC has to process the low periods of this signal.
Blockdiagram
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Version 1
Topview of the first circuit
Index
description
A
RISC Microcontroller AT90S8535
B
RS232 interface converter
C
ISP connector
D
2, 5V-switching regulators 78SR105VC
E
accelerometers (SMD) ADXL202
AT90S8535: The RISC-controller continuously drives the 12 servos via pulse width
modulated signals. Communicating via the serial interface with the PC, where a
VB program is running, the position-values for the servos get transfered. The
ISP-connector is used to programm the controller directly in the system (ISP, in system
programming).
Further information and datasheets :
www.atmel.com
Accelerometers (ADXL202): Those are used to measure the orientation of the controlling
unit (hip) to the earth's surface. In the future the moving algorythms will get
automatically improved (learnmode) and changes of the robots environment will take
affect. For now these values do not have any effect on the moving algorithms, they are
Further information and datasheets :
www.analog.com
Blockdiagram