Usable Simulink Embedded Coder Target for Linux

Transcription

1 Usable Simulink Embedded Coder Target for Linux Michal Sojka, Pavel Píša Czech Technical University in Prague Faculty of Electrical Engineering Department of Control Engineering 16 th Real-Time Linux Workshop October 12, 2014 Düsseldorf, Germany M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 1 / 22

2 Motivation Not everybody is a programmer Control engineers can design control algorithms but cannot program them in C M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 2 / 22

3 Motivation Not everybody is a programmer Control engineers can design control algorithms but cannot program them in C They use tools like Simulink to simulate their algorithms They still want to run their algorithms on real hardware, not just simulations M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 2 / 22

4 Motivation Not everybody is a programmer Control engineers can design control algorithms but cannot program them in C They use tools like Simulink to simulate their algorithms They still want to run their algorithms on real hardware, not just simulations Solution: Matlab/Simulink + automatic code generation M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 2 / 22

5 Motivation Not everybody is a programmer Control engineers can design control algorithms but cannot program them in C They use tools like Simulink to simulate their algorithms They still want to run their algorithms on real hardware, not just simulations Solution: Matlab/Simulink + automatic code generation Control applications = real-time applications while (1) { read input; calculate control; write output } M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 2 / 22

6 Motivation Not everybody is a programmer Control engineers can design control algorithms but cannot program them in C They use tools like Simulink to simulate their algorithms They still want to run their algorithms on real hardware, not just simulations Solution: Matlab/Simulink + automatic code generation Control applications = real-time applications while (1) { read input; calculate control; write output } The generated code needs to run on RTOS, e.g. GNU/Linux M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 2 / 22

7 What is Simulink? Widely used tool for design and simulation of dynamic systems Commercial, non-free program a part of Matlab Developed by MathWorks In its core is a solver of differential equations Algorithm is drawn as a data-flow graph (= Simulink model) Simulink can simulate it Simulink can generate C code of the model M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 3 / 22

8 Why people use it? M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 4 / 22

9 Code generation in Simulink Example: double in1, out1; in1 = adc_read(1); out1 = sin(t) + 3 * in1; dac_write(1, out1); Sine Wave 3 Constant Pin 1 ErrFlag Analog Input Product Pin 1 ErrFlag Analog Outpu M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 5 / 22

10 Code generation in Simulink Example: double in1, out1; in1 = adc_read(1); out1 = sin(t) + 3 * in1; dac_write(1, out1); Sine Wave 3 Constant Pin 1 ErrFlag Analog Input Product Pin 1 ErrFlag Analog Outpu Simulink Coder & Embedded Coder Code generation target Template for main.c Template for Makefile I/O blocks M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 5 / 22

11 Can Simulink generate code that runs on Linux? M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 6 / 22

12 Can Simulink generate code that runs on Linux? Yes, but... M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 6 / 22

13 Problems of Simulink code generation targets for Linux Very good support for popular embedded boards (Raspberry Pi, BeagleBone,... ) M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 7 / 22

14 Problems of Simulink code generation targets for Linux Very good support for popular embedded boards (Raspberry Pi, BeagleBone,... ) Can only be installed on Windows hosts M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 7 / 22

15 Problems of Simulink code generation targets for Linux Very good support for popular embedded boards (Raspberry Pi, BeagleBone,... ) Can only be installed on Windows hosts Other Linux targets are fortunately supported via IDE Link M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 7 / 22

16 Problems of Simulink code generation targets for Linux Very good support for popular embedded boards (Raspberry Pi, BeagleBone,... ) Can only be installed on Windows hosts Other Linux targets are fortunately supported via IDE Link Uses Eclipse IDE to compile and run the code Slow! M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 7 / 22

17 Problems of Simulink code generation targets for Linux Very good support for popular embedded boards (Raspberry Pi, BeagleBone,... ) Can only be installed on Windows hosts Other Linux targets are fortunately supported via IDE Link Uses Eclipse IDE to compile and run the code Slow! Generated code uses POSIX timers POSIX timers do not guarantee real-time properties (latencies) even under preempt_rt M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 7 / 22

18 POSIX timers under preempt_rt Linux POSIX timers use signals to notify user space about their expiration Signal delivery path uses sleeping locks under preempt_rt Deferred to softirq Softirqs are: executed in the context of arbitrary task or ksoftirqd executed with random (e.g. non-real-time) priority M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 8 / 22

19 Is there better code generation target? Yes ERT_LINUX M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 9 / 22

20 ERT_LINUX code generation target Goal: Minimalist target which reuses as much Simulink code as possible (not that easy) No Eclipse needed Uses clock_nanosleep() for timing External mode Works both natively and with cross-compiling M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 10 / 22

21 ERT_LINUX I/O support MF624: PCI data acquisition card Digital IO, Analog IO, PWM out Counters (can be used for PWM input!) Incremental encoder input Based on UIO driver no syscall overhead M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 11 / 22

22 ERT_LINUX I/O support MF624: PCI data acquisition card Digital IO, Analog IO, PWM out Counters (can be used for PWM input!) Incremental encoder input Based on UIO driver no syscall overhead CAN bus transmit/receive Some support for Raspberry Pi M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 11 / 22

23 ERT_LINUX I/O support MF624: PCI data acquisition card Digital IO, Analog IO, PWM out Counters (can be used for PWM input!) Incremental encoder input Based on UIO driver no syscall overhead CAN bus transmit/receive Some support for Raspberry Pi No Comedi yet M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 11 / 22

24 Applications/demos M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 12 / 22

25 PMSM motor simulation Hardware-in-the-loop (HIL) simulation Linux, preempt_rt Motor & fault simulation PC MF624 I/O card Interface board Infineon TriBoard running a motor control algorithm CAN bus USB (serial line, JTAG,...) PC Linux, CAN CAN attacks PC Infoneon Device Access Server (DAS) Analysis of how does security influences safety PMSM motor 20 khz Hand-written motor control algorithm runs on real hardware Message authentication on CANbus + brute force attacks M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 13 / 22

26 Robot with parallel kinematic structure I 4 DC motors, 4 incremental encoders, other I/Os I Presented at Embedded world 2014 I Sampling period 1 ms but complex computations I More reliable that previously used Windows target M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 14 / 22

27 Motor control on Raspberry Pi Final task for students of our real-time course: Create software motor controller on an embedded PowerPC board with VxWorks Can the same be implemented on Raspberry Pi with Linux? M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 15 / 22

28 M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 16 / 22

29 Hardware Motor Power Supply DIR HI DRV HI DRV Raspberry Pi P1 PWM GPIOs IN LO DRV DC MOTOR IN LO DRV CHA CHB IRC As simple as possible Four NOR gates (SN74HCT02) H-bridge (L6203) M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 17 / 22

30 Incremental encoder (IRC) processing The most demanding part IRC signal: 0 20 khz Every edge generates an interrupt (up to 80 k interrupts/sec) Kernel driver to calculate the position M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 18 / 22

31 Incremental encoder (IRC) processing The most demanding part IRC signal: 0 20 khz Every edge generates an interrupt (up to 80 k interrupts/sec) Kernel driver to calculate the position Sustainable IRQ frequency up to 32 khz Further improvement: Use of ARM FIQ M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 18 / 22

32 IRC processing details Hard IRQ IRQ threaded handler Raspberry Pi GPIOs CHA CHB IRC Position calculation works better if derived from the order of IRQs than from the signal values read in the handler. FIFO run queue preserves order! M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 19 / 22

33 Demo: Raspberry Pi motor controller 0 double uint8 onv sfircinput int32 0 RESET To int IRC0 IRC-display Convert double IRC int32 to Real IRC-scope 0 Position Request double Position double Pos Trajectory double double w r RSTs red I Opt. PSD Controller P Subsys PSD -Kdouble Anti Windup Active Output Range u I double Manual PWM double Manual PWM Control PWM PWM-display double PWMwDirOutpu PWMwDir M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 20 / 22

34 Demo: Raspberry Pi & CAN M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 21 / 22

35 Conclusion ERT_LINUX target works Used in several applications Does not suffer from serious problems as original MathWorks code generation targets. Limited support for I/Os Blocks for Comedi are on our todo list It might be possible to use our target with other I/O blocks (e.g. from MathWorks) M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 22 / 22

36 Conclusion ERT_LINUX target works Used in several applications Does not suffer from serious problems as original MathWorks code generation targets. Limited support for I/Os Blocks for Comedi are on our todo list It might be possible to use our target with other I/O blocks (e.g. from MathWorks) Thank you! M. Sojka, P. Píša Usable Simulink Embedded Coder Target for Linux RTLWS16 22 / 22