計測自動制御学会東北支部 第 213 回研究集会 (2003.12.12)
資料番号 213-12

Modular Platform for a Bilateral Master/Slave Manipulator forHydraulic Machines.
Eric Rohmer, Takayuki Takahashi, Eiji Nakano
Tohoku University
キーワード : computer integration, modular architecture, hydraulic machines, master-slave, force
feedback

連絡先 : 〒 982 仙台市青葉区荒巻字青葉 01 東北大学大学院 情報科学研究科 中野・高橋研究室
ROHMER Eric, Tel.: (022)217-7025 Fax.: (022)217-7023 E-mail: eric@robotics.is.tohoku.ac.jp

1.

INTRODUCTIONa new architecture for civil engineering machines must take into account the following

Civil engineering machines like excavators, de-constraints:

molition machines and other special concrete
injection machines are commonly used in con-• manoeuvrability of the machines: howstruction sites because a lot of building tasks

to cope with the complex system of levers

require large forces. All these machines have inand the complexity of the tasks,

common that they own a tool (bucket, grind-• interoperability: how to add remote con-ing tool, concrete injection gun, etc.) linked totrol features to the machines, replace aa n Degrees of Freedom (DOF) hydraulic armreal machine by a virtual one, etc.,

driven by hydraulic cylinders. To learn how• diversity: how to deal with the diﬀerent

to use each kind of machines, the user must

kind of civil engineering machines.

be well trained as he has to manipulate eachlink of the arm separately using a complex sys-

In this paper, we present a solution based

tem of lever. In order to get coordination andon a new software architecture. This archi-

to be able to work quickly and accurately, thetecture is based on the integration of a com-worker needs several years of training. More-puter system using a modular approach. In theover, in some cases like concrete injection orﬁrst part, we show how we answer the prob-building destruction work, the user inside thelem of manoeuvrability using a master/slave

machine is exposed to danger due to the risk

force feedback control system. In the secondof falling crumbles.

part, we describe the communication process

Regarding these problems, the design of

between the diﬀerent parts of the system. Finally, we show advantages and applications of–1–

the user have no feedback about the forces apBoom

Dipperplied to his tool at the end of the arm. ItCabine

has been proved that an assembly task, for instance, can usually be completed much faster
when the operator has a feel for the forces andtorques caused by contact 3) . And in case

BucketFig. 1 Motion of the bucket in a straight pathof a destruction of a house, in Japan, somenew ecological rules constrain the civil engi-

the proposed platform, like the use of diﬀerent

neering companies to separate concrete, iron,kind of manipulators of virtual system simula-and wood from the heap of rubble. It becomestors.

much easier to sort those materials while grinding the building than sorting them from the2.

Manoeuvrability enhancement
rubble. with a force feedback the user couldof the machines

2.1

The classical approachknow in which pile to drop what he just tookout of the building.

At a ﬁrst point, one should notice that conventional control device of hydraulic machines isState-of-art of solutions using robotics

corresponding to two (or more) levers directly

This concept of using robotic ﬁeld to solve theconnected to the valves that controls the pres-problem of the control system for hydraulicsure in each cylinders. The user controls eachjoints that means that each parts of the exca-machines has been widely studied by Nakano
et al.1) and Lawrence et al.2) . They suggest

vator separately. In other words, the user isto :controlling the position and orientation of thetool in joint mode. The tool control is thenvery diﬃcult, because this control is not in-• replace the system of levers by a more ergonomic and instinctive manipulator (Fig.
2 ),tuitive. Each lever can operate two types ofcommand (for an excavator: right lever com-

• use a master/slave architecture to put

mands boom/bucket, and left lever commands

intelligence between the manipulator (mas-cabin/dipper). In case of a backhoe, in or-ter) equipped by encoders on each artic-

der to build a slope (Fig. 1 ), the operator

ulations and the hydraulic arm (slave)

has to move the bucket, the dipper and theequipped by linear encoders on each cylin-boom simultaneously. To keep the bucket inders in order to control directly the toola special orientation to the ground, it is nec-

(with diﬀerent kind of control policies likeessary to move both of the lever in a diﬃcult

position, speed,etc. in diﬀerent mode likegradually changing diagonal motion, in order

Cartesian, slope, etc.),

to control the three gradually changing angles
for a smooth motion. The second point is that–2–• make the system bilateral, in order to
add a force feedback feature (need of ad-ditional pressure sensors on the cylinders– We want to display information fromor torques sensors on the tool for thethe master and slave manipulatorsslave manipulator to have an endpoint• A modular design in order to deal withsensing, and motors on the master to trans-

several master and slave conﬁgurations

mit force on the user’s hand.

2.2and communication mediums (see section

Integration of an intelligent module

3 advantages and applications of the proposed plate-form)

In our research we introduce the concept of intelligent module between the manipulator (called3.

master manipulator) and the hydraulic arm

Interoperability between thediﬀerent components of thesystem(called slave manipulator). This module is acomputer system (with a variable complexity:

The intelligent module concept allows to haveone or many communicating computers), anddiﬀerent features like an easy master and slave

has the following characteristics :replacement, a remote control feature, building site management, etc. . But we can see• It is an interface between master andthat for all of them, the intelligent module haveslave manipulator. We need to abstract

to be able to manage communication (hard-a communication layer (see section 2 In-

ware and software) between the diﬀerent parts

teroperability between the diﬀerent com-

: master manipulator/ computer system, slave

ponents of the system)

manipulator / computer system, and comput-• It owns a virtual image (geometry, spec-ers inside the computer system. We need theniﬁcations, current angular conﬁguration

to abstract a communication layer. In this re-etc.) of both master and slave manipu-

search the idea is to :lator, updated at each time step• consider the master and the slave manipulators as two modules linked to the• Computation capabilities as:

intelligent module.
– Forward, Inverse, Velocity Kinematics etc. are required to be computedfor the management of the bilateralcontrol of master and slave manipulators.

So the concept ofslave module is a real (or a simulation ofthe) slave manipulator linked to an independent process called slave process.
The master module is a real (or a simulation of the) master linked to a indepen-– We need enhanced capabilities indent process master process. And the in-order to let the user select diﬀer-telligent module is system of computers

ent working mode to help him in his(or only one computer) where a control

task (Cartesian, slope, pattern, etc.

management process (brain process) andmode)

master and slave processes are running.

–3–

So each module have his own communi-

4.2

cation layer, that allows to have a remote

Simulation system

control of the hydraulic machine.

We developed a simulation system:• have an abstracted communication layer:• advantages: with the simulation system– each components of each modules

we can test diﬀerent conﬁguration andare communicating with each othersimulate the connection to any kind ofusing an IO manager, what ever theslave or master manipulators. For exam-communication medium is: TCP/IP

ple we can test the system on a hydraulic

Ethernet based communication ( canmachine that does not exist like a two

be WIFI), serial line, a bus connectedarms one, and plug two masters (virtualto a FPGA card or a PCI card , etc.

or real) to test the ergonomic of the system.

– the communication protocol is normalized (data packetization / un-• speciﬁcations: for the dynamic calcula-packetization)

tion, the Open Dynamic Engine classes
are used 4) , and OpenGL for the 3D dis-That allows an easy interchangeability

playing 5) .

of masters and slaves manipulators and4.
4.1

Validation of the platform

modularity of the architecture(Fig. 3 ).

• Tested master manipulators: we did suc-

Advantages and applicationsof the proposed platform

cessfully test a new kind of master ma-

Characteristics of the plate form

5 DOF Komatsu excavator, adding Carte-nipulator called mono-lever, on a virtual

sian, and slope mode with force reﬂectThe platform characteristics are:ing.

• Object Oriented Platform: coded in C++

Results

languageThanks to the modular system we did test many
• multi OS: the processes can be compiled
to run on windows, Unix/Linux

ter manipulator or a real one (plugged to a• Modular system: the processes can be

FPGA+sh4 connected to the intelligent module through a serial port), controlling a virtual

run on one or diﬀerent computers
An architecture example is shown in (Fig. 4 )The slave process is running in an embedded
computer and the master and brain process are
running on a remote computer. The intelligent
module is then composed on two computerscommunicating through a wireless LAN.

diﬀerent conﬁgurations, using a virtual mas-slave. We used an intelligent module composedby one to three computers communicated witheach other through the LAN. This modularsystem allowed us to test many characteristics
like delay in the system,force feedback accuracies, ergonomic of some manipulators, etc.

–4–

5.

Conclusion

This integration opens to civil engineering work,
the way of teleoperation, task helping numerically control, possibility to train the worker
on a simulator.

It allows us to change thetopology of the master/slave system by easily
deports the brain in a powerful remote computer. The well known concept of Computer
Integrated Manufactory can be translated tothe management of building-sites.

参考文献
1) E. Nakano, N. Tsuda, K. Inoue, K.
Kayaba, H. Kimura, T. Matsukawa, Development of an Advance Way of Improvement of the Maneuverability of a Backhoe
Machine, 9th ISARC, June 3 - 5, 1992,
Tokyo, JAPAN2) P.D. Lawrence, B. Sauder, U. Wallersteiner, and J. Wilson, ”Teleoperation offorest harvesting machines,” in Robotics
in Forestry, (Vaudreuil, Quebec), pp. 3639, September 1990
3) D. Stokic, M. Vukobratovic, and D. Hristic, Implementation of a force feedback inmanipulation robots, International Journal of Robotics Research, vol. 5, pp. 66-67,
Spring 1986.
4) http://opende.sourceforge.net/5) http://www.opengl.org/–5–Fig. 2

Ergonomic master manipulator using Cartesian mode

Master Module

Slave ModuleIntelligent Module
Brain Process
Master Image

7DOF PA10

Slave image...
Outside the excavator

WLAN

WLAN

OROR
serialIntelligent module

Fig. 4sh4 + fpga

Serial port

IPC

Slave Module

bus

FPGAbusslave simulation

Processes:
masterBrainCamera

Inside the excavator

FPGAUSB

5DOF komatsu
IO
managerModularity of the architecture

Processes:
slave

CameraSlave
Process
PCI, FPGA, ...

Fig. 3

FK Slave

LAN or Loopback

master simulation

LAN or Loopback

serial, FPGA, ...

IO
manager

IK Slave

FK master...

lever kind master

IK masterIO Manager

MasterProcess

IO Manager

monolever kind masterany kind of master manipulator

Master Module

Remotely controlled work

–6–