Rapid Controller Prototyping at the SUPSI...

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


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)


dsPIC

• 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


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


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

code

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


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


Other useful links

• www.rtai.org• www.osadl.org• robertobucher.dti.supsi.ch/• www.dti.supsi.ch/~smt/laboO4.html

http://www.rtai.org/


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