Sc mc python examples
Contents
special command sequences that are interesting
Below are some special command that result in some interesting robot behavior. These special commands can be provided via 'do_command.py', or 'pfcmdmenu.exe', or directly in python with the method 'do_command' in the module 'pfcmd.py'.
The special command sequences below are listed in braces as comma separated values. For example for the sequence [100, 200, 300]
With do_command.py you would type: do_command.py -p <serial port> -s 100 200 300
With pfcmdmenu.exe, in the string box : 100 200 300
With python, assuming pf is an instance of pfcmd.py: result = pf.do_command('special', [100, 200, 300])
read robot status
- [104] # read SC status info
- [1101] # get motor mode
- [1106] # get encoder positions
- [1420] # get MC SM state
- [1105] # get motor velocity
- [1116] # read MC ADCs
- [1120] # get overload status values
- [230] # get IMU enable
prepare the hardware
Take the robot out of its boot mode so that it can be controlled externally. Generally the following special commands achieve this:
- [231, 0] # IMU off - to minimize possible loss of commands over the FUP
- [173,77,7] # demux statemachine to idle mode
- [170,77,17] # primary statemachine to the 'do nothing state'
- [1421, 17] # MC statemachine to a 'do nothing success state'
move robot back - fort in voltage mode
After preparing the hardware above, can use special command 1115 to command a fixed voltage across the motor:
- [1115, 1000, 0, 6] # qVq = 1000, mode = 6 (voltage
- sleep 1 sec
- [1115, -1000, 0, 6] # qVq=-1000
- sleep 1 sec
- [1115, 0,0,0] # short the motor leads
enter trajectory mode
The trajectory mode will servo the robot to the goal position. This is achieved by adjusting the sent point of a virtual spring (whos parmeters) are adjusted. The goal point for the VS is set based on diffeence equstion that produces an exponential response to a position step input.
- [1318, 100] # set goal position to 100 need to be careful to limit the goal position to valid positions!!!
- [1421, 41] # go to trajectory control mode, robot immediatly jumps!
- sleep 1 sec
- [1318, 500] # servo to position 500
python examples
########################## # BASIC CODE REQUIRE TO ESTABLISH A ROBOT CONNECTION ########################### # update the python path variable import python_paths_default import python_paths as pyenv import pfcmd # robot communication module COM_PORT = 17 # use device manager to determine port # pf = pfcmd.PFCmd(0, 0); # instance of communication module pf.connect(COM_PORT, 115200); # baudrate=115200
#################################################### # send special commands to 'prepare the hardware' #################################################### pf.do_command('special',[173, 77, 7]); pf.do_command('special',[170, 77, 17]); pf.do_command('special',[1421, 8]); pf.do_command('special',[173, 77, 6]); pf.do_command('special',[170, 77, 17]);
#################################################### # move robot with voltage mode #################################################### for i in range(0,10) : print i pf.do_command('special',[1115, 2000, 0 ,6]); time.sleep(1.0) pf.do_command('special',[1115, -2000, 0 ,6]); time.sleep(1.0) pf.do_command('special',[1115, 0]);
#################################################### # do some trajectory control ####################################################
pf.do_command('special',[1318, 0]); # set goal position pf.do_command('special',[1421, 41]); # enter trajectory mode
for i in range(0,10) :
pf.do_command('special',[1318, 500]); # change goal position time.sleep(0.5); pf.do_command('special',[1318, 50]); time.sleep(0.5);
pf.do_command('special',[1421, 17]); # back to MC idle state
pf.do_command('special',[1115, 0]); # short leads
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