Rapid Controller Prototyping at the SUPSI...

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DTI / ISEA / LSM / Titolo principale della presentazione

Rapid Controller Prototyping at the SUPSI laboratory

Prof. Roberto BucherSUPSI - ISEA – SMT

Manno 9.05.2014

Outline

• The mechatronics laboratory at SUPSI• The SUPSI Rapid Control Prototyping System• Linux RT systems and other targets• The Computer Aided Control System Design environments• The CAN bus approach• Examples• Conclusions

Introduction – SUPSI Labor Place

The Control Design Loop

The RCP system

• A general purpose PC• Different OS's with real-time features• Different CACSD environments including a code generator• Plants built on commercial CAN bus capable devices• A physical CAN bus interface

The RCP system

CACSD: Matlab/SimulinkScicoslabScilab/xCosPython/gEDA

OS: Linux RTAILinux Preempt-RT

The RCP system

RCP methods

• Design of the controller in the CACSD environment (Matlab, Scilab, Scicoslab, Python)

• Hybrid (discrete controller, continous plant) simulation of the controller with the dynamic model of the plant

• Substitute the model of the plant with sensors and actuators blocks

• Substitute the scopes with RT scopes• Generate and compile the code• Verify the controller on the real plant

RCP methods

The RT targets

The Linux RTAI project

• Hard real-time extension to the Linux OS• Project from Dipartimento di Ingegneria Aerospaziale del Politecnico di Milano• SUPSI is involved in project since 2002 (first automatic generation of a kernel

task from a Simulink block diagram)• Free Open Source Software (FOSS) • Same PC for the controller design, for the hard real-time controller task and

for the soft real-time monitoring task• Hard real-time in kernel and user space• RTAI API• Distributed control through the net_rpc modul• Latency: < 15 µs on modern HW• Typical sampling frequencies: 1 ... 10 kHz

RTAI projects

http://www.gb.nrao.edu/43m/

http://www.inrialpes.fr/sed

RTAI projects

http://www.alma.nrao.edu/

RTAILab

RTAI-XML

http://www.rtaixml.net/realtime-suite

RTAI-XML

http://www.rtaixml.net/realtime-suite

The Linux Preempt-RT project

• Real-time extension to the Linux OS (Ingo Molnar - RedHat, Thomas Gleixner - Pengutronix)

• Free Open Source Software (FOSS) • Same PC for the controller design, for the real-time controller

task and for the monitoring task (browser)• real-time in user space• POSIX API• Latency: < 50 µs on modern HW• Typical sampling frequencies: 100 ... 1000 Hz• IBM - WebSphere Real Time (Java RT)

Linux with preempt_rt

www.osadl.org

XML Browser from Klaus Weichinger

http://bioe.sourceforge.net/

Linux ARM systems (with rt_preempt patch)

• C-Code• MPLABX project• dsPIC 33FJ64MC810• dsPIC 33FJ64MC804

The CACSD Environments

Matlab / Simulink / RTW

• Matlab for solving the control design algorithms• Simulink for hybrid simulation• Real Time Workshop for C-Code generation• Linux RTAI as RT target

– RTAI.tlc + RTAI.tmf developed at SUPSI with Dipartimento di Ingegneria Aerospaziale del Politecnico di Milano (DIAPM)

• Commercial licences! (quite expensive)

Matlab/Simulink/RTW

disksRT.cdisksRT.hdisksRT_data.c....

rtai.tmf

disksRT.mk

Matlab/Simulink/RTW

rtai.tmf

disksRT.mk

Mathworks libs RTAI and custom libs

Matlab/Simulink/RTW

rtai.tmf

disksRT.mk

Mathworks libs

RT standalone executable

RTAI and custom libs

CACSD – Matlab / Simulink / RTW

• Matlab / Simulink are “de facto” THE TOOLS in education

CACSD – Matlab / Simulink / RTW

• Matlab / Simulink are “de facto” THE TOOLS in education

• But...– What happens wenn our (ex-) students have to develop

advanced control systems in little companies?– Mathworks commercial licenses are too expensive for

most little companies!

Scicoslab

• Developed by INRIA Rocquencourt• Fork of the scilab project• Scicos for hybrid simulation• Modelica extension (bond graphs)• Original code generator modified by Roberto Bucher for embedding

in target• Integration with Linux RTAI, Linux preempt_rt and dsPIC embedded

systems possible• Not open source but free

• Next version should be called NSP

Scilab / xCos

• Developed by INRIA Rocquencourt• Xcos for hybrid simulation• Modelica• Original code generator modified by Roberto Bucher for

embedding in target• Integration with Linux RTAI and Linux preempt_rt possible

(CTI project 13910.1 PFIW-IW)• Cecill licence (like GPL licence)

Scicoslab (or scilab+Xcos)

disksRT.c....

rtai.tmf

Makefile

disksRT.c....

rtai.tmf

Makefile

Scicos libs RTAI and custom libs

disksRT.c....

rtai.tmf

Makefile

Scicos libs

RT standalone executable

RTAI and custom libs

Python

• Project started at Centrum Wiskunde & Informatica in the Netherlands (1989)

• Control Toolbox from Richard Murray (Caltech)• Additional functions from Roberto Bucher (SUPSI) for

– Correcting some bugs in Control Toolbox– Solving complex control tasks– Adding hybrid simulation– Code generation (Linux with preempt_rt now)

• Python Software Foundation License (PSFL) (like BSD)

gEDA tools

• Open source tool for generating block diagram• Custom blocks are possible• From schematics it is possible to generate a netlist• A python tool translate the netlist into python blocks for code

generation (C-Code)

Python / gEDA

* Spice netlister for gnetlistDISP 2 4 3 nin:3,nout:0,printBlkSRV nin:0,nout:0,rtxmlServerBlk,Signals Plot1: 'Sig1 Sig2',Signals Plot 2: 'Sig1',Signals Plot 3: 'Sig2',Additional XML Par: '<PAR></PAR>',HTTP port: 3141OUTPOS 4 nin:1,nout:0,rtxmlSigBlk,Signals Name: 'Sig2',Default Value: 0.0OUTREF 2 nin:1,nout:0,rtxmlSigBlk,Signals Name: 'Sig1',Default Value: 0.0ENC2 4 nin:0,nout:1,maxon_EncBlk,Device ID: 0x02,Resolution: 500ENC1 3 nin:0,nout:1,maxon_EncBlk,Device ID: 0x01,Resolution: 500MOTOR 7 nin:1,nout:0,maxon_MotBlk,Device ID: 0x01,Prop. gain: 8000,Integ. gain: 4000CTRFBK 7 6 nin:1,nout:1,dssBlk,System: gss_out,Initial conditions: 0SAT 5 7 nin:1,nout:1,saturBlk,Upper saturation:3000,Lower saturation: -3000B1 1 6 5 nin:2,nout:1,sumBlk,Gains: [1,1]REF 2 nin:0,nout:1,squareBlk,Amplitude: 4,Period: 10,Width: 5,Bias: 0,Delay: 0CTRIN 2 3 4 1 nin:3,nout:1,dssBlk,System: gss_in,Initial conditions: 0.END

Python / gEDA

from supsictrl.RCPblk import *

DISP = printBlk([2, 4, 3])SRV = rtxmlServerBlk( 'Sig1 Sig2', 'Sig1', 'Sig2', '<PAR></PAR>', 3141)OUTPOS = rtxmlSigBlk([4], 'Sig2', 0.0)OUTREF = rtxmlSigBlk([2], 'Sig1', 0.0)ENC2 = maxon_EncBlk([4], 0x02, 500)ENC1 = maxon_EncBlk([3], 0x01, 500)MOTOR = maxon_MotBlk([7], 0x01, 8000, 4000)CTRFBK = dssBlk([7],[6], gss_out, 0)SAT = saturBlk([5],[7],3000, -3000)B1 = sumBlk([1, 6],[5], [1,1])REF = squareBlk([2], 4, 10, 5, 0, 0)CTRIN = dssBlk([2, 3, 4],[1], gss_in, 0)

blks = [DISP, SRV, OUTPOS, OUTREF, ENC2, ENC1, MOTOR, CTRFBK, SAT, B1, REF, CTRIN]fname = 'disksRT'genCode(fname, 0.01, blks)genMake(fname,'rt.tmf')

Interfacing the real plants

CAN Bus interface - Motivation

• Teaching environment based on tools found in industry• COTS components (multiple vendors)• Simplified maintenance and reduced costs• Easy expendability and flexibility of didactic activities

CAN bus – the 4-tier implementation

• Combination of– Different CAN devices

– Different CACSD environments

– Different CAN interfaces

• Combination of– Different CAN devices

– Different CACSD environments

– Different CAN interfaces

Complexity for specific SW interfaces unmanageable

Structured approach

95% same code

Different CAN interfaces

Message dispatcher

devicespecific

PhysicalLayer

interface

CACSDspecific

layersimulink

ScicosXcos

python

Example – Disks And Spring

Inverted Pendulum

Delta haptic manipulator

Other projects

Labo example

Example – Disks and spring

Model identification

Controller

Controller in compact form

Matlab + Simulink

Scicoslab + Modelica

Python implementation

Code generation

• Find the right block sequence• Generate the C code with 3

functions:– Init

• Initialization– ISR

• Outputs update• States update

– Termination

continous time systems discrete time systems

Block Diagram for simulation

Block diagram for RT execution

Python / gEDA / RT execution

from supsictrl.RCPblk import *

DISP = printBlk([2, 4, 3])SRV = rtxmlServerBlk( 'Sig1 Sig2', 'Sig1', 'Sig2', '<PAR></PAR>', 3141)OUTPOS = rtxmlSigBlk([4], 'Sig2', 0.0)OUTREF = rtxmlSigBlk([2], 'Sig1', 0.0)ENC2 = maxon_EncBlk([4], 0x02, 500)ENC1 = maxon_EncBlk([3], 0x01, 500)MOTOR = maxon_MotBlk([7], 0x01, 8000, 4000)CTRFBK = dssBlk([7],[6], gss_out, 0)SAT = saturBlk([5],[7],3000, -3000)B1 = sumBlk([1, 6],[5], [1,1])REF = squareBlk([2], 4, 10, 5, 0, 0)CTRIN = dssBlk([2, 3, 4],[1], gss_in, 0)

blks = [DISP, SRV, OUTPOS, OUTREF, ENC2, ENC1, MOTOR, CTRFBK, SAT, B1, REF, CTRIN]fname = 'disksRT'genCode(fname, 0.01, blks)genMake(fname,'rt.tmf')

Conclusions

• Investment of resources !– Gain of experience

– Gain of knowledges

• Appreciated by the students• Forms students with reusable skills• Easy to maintain and to develop• Synergies with research activities

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