Hello David and others On Thursday 27 of February 2025 17:28:16 David Jander wrote: > Request for comments on: adding the Linux Motion Control subsystem to the > kernel. I have noticed on Phoronix, that the new system is emerging. This is area where I have lot (more than 30 years) of experience at my company and I have done even lot with my studnets at university. I have big interest that this interface fits our use neeeds and offers for future integration of our already open-source systems/components. This is preliminary reply, I want to find time for more discussion and analysis (which is quite hard during summer term where I have lot of teaching and even ongoing project now). I would like to discuse even future subsystem evolution which would allow coordinates axes groups creation, smooth segments based on N-th order splines incremental attachment, the path planning and re-planning if the target changes as reaction to camera or other sensor needs etc. At this moment I have interrest if there is site which would start to collect these ideas and where can be some references added. I think that I have quite some stuff to offer. To have idea about my direction of thinking and needs of interface I would provide some references even to our often commercially sold but mostly conceived as hobby projects. Coordinated axes groups movement with incremental spline segment addition into command queue (our COORDMV componet of PXMC library) is demonstrated on old BOSCH SR 450 SCARA system. The robot has never fully worked at Skoda Auto with original BOSH control unit. But when it has been donated to Czech Technical University, we have build control unit at my copany based on Motorola 68376 MCU in around 2000 year. I have later paid one student to prepare demo in Python to demonstrate the system. You can click on video MARS 8 BigBot and Robot Bosch SR 450 Drawing Roses http://pikron.com/pages/products/motion_control.html The related python application is there https://github.com/cvut/pyrocon In the far future, I can imagine that it can connect to proposed LMC API and achieve the same results. The related control unit MARS 8 page http://pikron.com/pages/products/motion_control/mars_8.html CPU board for museum or curiosity http://pikron.com/pages/products/cpu_boards/mo_cpu1.html The firmware main application https://gitlab.com/pikron/projects/mo_cpu1/mars-mo_cpu1 which uses our PXMC motion control library https://gitlab.com/pikron/sw-base/pxmc There is basic documentation for it on its site https://pxmc.org/ https://pxmc.org/files/pxmc.pdf It is used in system less environment on the MARS 8 system and actual control at fixed sampling frequency is done in timer interrupt at 1 kHz. More such units serve our studnets to control CRS A465 robots for more than 20 years already. Their original control units have broken by age... The same library has been used in our design of HW and SW for infusion systems (MSP430 + iMX1 with RTEMS) https://pikron.com/pages/devel/medinst.html HPL systems (LPC1768 HW) http://pikron.com/pages/products/hplc/lcp_5024.html and on newer system less LPC4088 + Xilinx XC6SLX9 system used for example for more ESA and ADS projects https://www.esa.int/ESA_Multimedia/Images/2023/06/W-band_on_the_run https://github.com/esa/lxrmount https://gitlab.com/pikron/projects/lx_cpu/rocon-commander/-/wikis/lxr-lisa-com The LX_RoCoN is based on FPGA design with up to 8 IRC inputs, 16 arbitrarily assignable PWM H-bridge output, TUMBL (open source Microblaze variant) co-processor for up to four electronic commutations for PMSM, stepper or IRC equipped steppers there https://gitlab.com/pikron/projects/lx_cpu/lx-rocon The commutation ((forward + inverse) x (Park + Clarke)) by co-processor runs on PMW frequency (20 kHz), D+Q current PI, position PID and COORMV at 4 kHz. FPGA design has been started in the frame of the next thesis https://dspace.cvut.cz/bitstream/handle/10467/23347/F3-DP-2014-Meloun-Martin-prace.pdf More Linux, RTEMS, NuttX, etc. theses led by me there https://gitlab.fel.cvut.cz/otrees/org/-/wikis/theses-defend More information often about RT, motion control there https://gitlab.fel.cvut.cz/otrees/org/-/wikis/knowbase Back to the GNU/Linux Experiment to run our PXMC library on Linux, demonstration on Raspberry Pi, AM4300, Xilinx Zynq with DC and PMSM motors https://gitlab.com/pikron/projects/pxmc-linux The HW with small FPGA implementing IRC, 3x PWM and current ADC commanding and collection which is connected to Raspberry Pi by SPI there https://gitlab.com/pikron/projects/rpi/rpi-mc-1 It is intended for demonstration to enthusiasts, not for industry. (I am not happy to see H2 filling stations controlled by RPi today...) But the same code can be run on Xilinx Zynq with DC motor peripheral https://gitlab.fel.cvut.cz/canbus/zynq/zynq-can-sja1000-top/-/tree/master/system/ip/dcsimpledrv_1.0 and PMSM peripheral https://gitlab.fel.cvut.cz/canbus/zynq/zynq-can-sja1000-top/-/tree/master/system/ip/pmsm_3pmdrv1_to_pins but there are even more advanced option even for Linux. The TUMBL coprocessor has been replaced by small RISC-V developed in the frame of our Advanced Computer Architectures course by my studnets https://gitlab.fel.cvut.cz/otrees/fpga/rvapo-vhdl and the 3 phase motor peripheral has been combined with this coprocessor on Zynq, So PREEMP_RT Linux (or even RETMS) can deliver D and Q PWM values to shared memory and coprocessor takes care about commutation at 20 kHz, then collects A, B, C currents and convert them at 20 kHz to D Q and filters them to deliver cumulative sum and accumulated samples count to the slower Linux control loop. But ARM core can access peripherals directly as well for debugging purposes etc. The Linux, RTEMS application source https://gitlab.fel.cvut.cz/otrees/fpga/rvapo-apps/-/tree/master/apps/rvapo-pmsm co-processor firware source https://gitlab.fel.cvut.cz/otrees/fpga/rvapo-vhdl/-/blob/main/software/c/firmware_fresh/firmware.c The 3-phase peripheral can be synthesized even by fully open source tool chain to iCE40 and PMSM motor control has been demonstrated even on cheap ICE-V Wireless (ESP32C3+iCE40)) with SW running NuttX https://gitlab.fel.cvut.cz/otrees/risc-v-esp32/ice-v-pmsm We have tatgets for the most of these peripherals under Linux and NuttX for pysimCoder https://github.com/robertobucher/pysimCoder Some examples ow pysimCoder is used by independed company there https://www.youtube.com/@robots5/videos It is on NuttX, but on RPi and Zynq it works even better on GNU/Linux. So in general, I think that we have large portfolio of building blocks which would allow to build motion, robotic controllers, communications etc. and I would be happy if they are reused and even some project conceived together with others to join the forces. It would be ideal if the all motion control related resources and links could be somehow collected that wheel is not reinvented unnecessarily. The most of my code is Mozilla, GPL etc... I have right to relicence my company stuff if the license does not fit. On the other hand, I do not intend to follow such offers as of one well funded chip related association, which offered us to relicense all to them with no retain of any control and additional right and they would not take care about the valuable project at all no looking for funding etc... no promise for developmet etc... So there are some limits. Best wishes, Pavel Pavel Pisa phone: +420 603531357 e-mail: pisa@xxxxxxxxxxxxxxxx Department of Control Engineering FEE CVUT Karlovo namesti 13, 121 35, Prague 2 university: http://control.fel.cvut.cz/ personal: http://cmp.felk.cvut.cz/~pisa company: https://pikron.com/ PiKRON s.r.o. Kankovskeho 1235, 182 00 Praha 8, Czech Republic projects: https://www.openhub.net/accounts/ppisa social: https://social.kernel.org/ppisa CAN related:http://canbus.pages.fel.cvut.cz/ RISC-V education: https://comparch.edu.cvut.cz/ Open Technologies Research Education and Exchange Services https://gitlab.fel.cvut.cz/otrees/org/-/wikis/home
