Module nri::optoforce

Service to read data from the OptoForce sensor

Optoforce drivers

The driver SDK shipped by Optoforce is crap. The example barely compiles, depends on Qt (for serial port access of all things), and core dumps the first time it is run (after that it freezes instead). The precompiled GUI application actually runs, which is a major step up, but it was compiled with an absolute path to the fonts directory in someone's home directory, so it requires a symlink under /home or an LD_PRELOAD library to display any characters. With that minor annoyance fixed, it shows numbers and plots that confirm the sensor works! It can even log values to a file, which may be useful for sanity checks later. But this isn't really good enough for our use case, unless we did some terrible hack such as starting the GUI to write to a file and having the NRI supervisor tail the file.

Luckily, third-party drivers exist. A quick search found liboptoforce, out of ETH Zurich, freely available on Github. I installed the software from their PPA. (The source is in a git submodule. Unfortunately building it requires ETH Zurich's own build system, called ReMake, which I also checked out into a submodule, but I can't get that to build, so I can't build liboptoforce either. Therefore, PPA it is.) I was able to compile the example program and it shows numbers from the sensor!

The ETH Zurich package includes a configuration program, which can set the sensor sample speed (among other things), and a statistics program which can measure it (among other things). Unfortunately, when to set to 1 kHz (the maximum) the sensor sends readings at only 500 Hz. This is probably still enough for us. A calibration program is also included, which will be useful for zeroing the sensor.

• Commands to install liboptoforce: $ sudo apt-add-repository ppa:ethz-asl/drivers $ sudo apt-get update $ sudo apt-get install liboptoforce*
• To compile and run the sample program: $ sudo apt-get install libboost-{system,thread,signals,chrono,program-options}-dev $ cd liboptoforce/src/bin $ make $ ./configure -d /dev/ttyACM0 -s 1000 $ ./statistics -d /dev/ttyACM0 -s $ ./dump_readings -d /dev/ttyACM0 -s $ ./calibrate -d /dev/ttyACM0

Reexports

use std::prelude::v1::*;

use super::comms::{Controllable, CmdFrom};

use std::sync::mpsc::{channel, Sender};

Structs

Optoforce