Haptic Interface for Intuitive Teleoperation of Wheeled and Tracked Vehicles Tien Si Nguyen Ba Hai

7/27/2019 Haptic Interface for Intuitive Teleoperation of Wheeled and Tracked Vehicles Tien Si Nguyen Ba Hai

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Haptic Interface for

Intuitive Teleoperation of Wheeled and Tracked Vehicles

Ba-Hai Nguyen[1]

, Jee-Hwan Ryu[2]

[1]Hochiminh University of Technical Education, Vietnam

[2]

Korea University of Technology and Education, Korea

ABSTRACT

In this paper, a novel haptic interface is proposed for generalteleoperation of wheeled and tracked vehicle. The newmechanism of the proposed haptic interface shown in Fig. 1 notonly allows human operator to easily tele-operate various types oftarget vehicles including car-like vehicles, mobile robots, tracked

vehicles, but also improve the operators perception of targetvehicles operating status and its environment by introducingcornering feel in the field of vehicle teleoperation. In addition,the proposed interface enables human operators to give commandsto (or drive) target vehicle in a way which is carried out in

traditional direct control or driving. Experiments have been doneto carefully evaluate and test the performance of the proposedinterface. The results have shown that the developed haptic masterdevice is sufficient and suitable for general wheeled and tracked-

vehicle teleoperation.

KEYWORDS: human-vehicle interface, teleoperation, wheeled,tracked, vehicle, mobile robot, human-robot interface, human-robot interaction

INDEX TERMS: K.6.1 [Designing haptic interface, Teleoperationand Control, Vehicular Robotics]

1 INTRODUCTIONIn teleoperation and control of wheeled and tracked vehicles, a

human operates and controls a target vehicle from a distance. Insuch operations, the human operators can not directly navigate thetarget vehicle and percept the vehicles status as well as its

environment. Therefore, a human-vehicle interface has become acrucial mean which provides robots status and environmentsinformation to human operator for accurate and intuitiveteleoperation and control. From this point of view, it isworthwhile to examine and study a novel interface forteleoperation of wheeled and tracked vehicles (WTV). In the

paper [1], the philosophy of the proposed haptic interface hasbeen presented and the preliminary results of this research havebeen illustrated that the proposed interface can be mapped to car-like vehicle and mobile robots. The proposed a novel interface for

the teleoperation of wheeled and tracked vehicles which isintuitive, effective. And, it can be a low-cost and portable human-

vehicle interface. With the proposed interface, operators not onlyintuitively teleoperate a target vehicle because

of its steering wheel-like interface, but also conveniently set the

desired speed to the target vehicle using joystick-like acceleratingpedals. In addition, operators could percept richer and morecomprehensive information of teleoperation such as the feel of theamount of steering angle, vehicle speed, and the feel of cornering

effect (a drivers feel when vehicle travels at road corners). As theresult, operator can interact and percept in the same manner indirect control using the proposed interface. In other words, with

proposed interface, teleoperation or remote control may closer tothe normal systems in which the human operators seat in or on the

target vehicles and drive them. Accordingly, these feels are thekey to help operator in maintaining control of the vehiclefollowing a desired strategy.

Beside mentioned advantages, the proposed interface enablesnumber benefits. In particular, several matching possibilities forassigning joint-variables of proposed interface to different targetvehicles as well as new schemes of force-feedback reflection.Those advantages have distinguished this research with others in

the field of intuitive interfaces for the teleoperation of wheeledand tracked vehicles.

After the first phase of this research presented in [1], thissecond phased of this research focuses on:

Deeply study matching strategies to map the proposed

interface to various types of target vehicle.

Demonstrate the matching capability by conducting severalexperiments with various types of vehicles.

Figure 1. The proposed interface

Base

Adjust

[1][email protected][2][email protected]

Steering wheel

Handles

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IEEE World Haptics Conference 201121-24 June, Istanbul, Turkey978-1-4577-0298-3/11/$26.00 2011 IEEE


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2 VEHICLE TELEOPERATION

2.1 Typical teleportation scenarios

The teleoperation of wheeled and tracked vehicles isshown in Fig. 2. By giving commands in term of speed, position,or force via haptic interface (master), a user at local side navigatesa target vehicle (slave) at remote side to a desired location. And atthe same time, he or she percepts the status or information oftarget vehicle and its environment in term of visual, hapic, audio,

and vision feedback. Based on the feedback signals, theperformance of teleoperation activities can be improved. Usually,there is a wireless network for exchanging data between themaster and slave.

Figure 2. Teleportation system of wheeled and tracked vehicles

2.2 Matching issues of vehicle teleoperation

One of the most technical difficulties in the teleoperationof wheeled and tracked vehicles is how to develop a generalintuitive interface in which users can perform the teleoperationtask easily, and the interface can be mapped to various types oftarget vehicles. It means that users operate the teleoperationsystem and percept similar feel in direct control. For example,users should see the vision in front of the target vehicle, and feelsteering force which applied to his or her hand like a conventionalsteering wheel. Accordingly, it is benefit to propose a generalinterface for the teleoperation of wheeled and tracked vehicles.And with a single proposed interface, there must be a certainmatching strategy for different types of vehicles.

2.3 General matching scheme of vehicle teleoperation

In teleoperation of WTV, several researches have proposeddifferent matching strategies which are used to map the master tothe slave. They include position-position matching strategy,

position-velocity matching strategy, and combined matchingstrategy. For instance, to map a PhanTOM to a mobile robot, the

positions of one or many joints of PhanTOM are used as referenceposition of mobile robot (position-position matching strategy).

Alternatively, the position of joints of the PhanTOM can be alsothe reference of mobile robots longitudinal velocity and angularvelocity (position-velocity matching strategy), or those matchingstrategy can be combined (combined matching strategy).

Lets consider an example of a typical and conventionalmatching strategy in which the positions of master are used as

reference velocities of left and right wheel of a mobile robot.For proposed interface shown in Fig. 3, the relationship

between human commands ( ml , and mr movement) and the

variables of mobile robot position-velocity matching strategy canbe expressed via equation 1.

=

0000

00

00

l

r

mc

mr

ml

mr

ml

k

k

&

&

(1)

where:

mlk , mrk are proportional gains.

ml , mr , mc are angles of axisleft ,and axisright , and axiscenter of the proposedinterface.

r& , l

& are angular velocities of right wheel and left

wheel of the mobile robot.

The proposed interface is matched to the robot with position-velocity strategy. It should be noticed that the axiscenter is

braked (using a HALL mode of actuator attached toaxiscenter ) in this strategy.

where:

pjxk , pjyk are proportional gains

1mp , 2mp , are angles of 1axis and 2axis of the

PhanTOM

mrX : is the translational speed of the mobile robot

mr : is the total rotation of the mobile robot.

When the proposed interface is used. the proposed interface hasthree degree of freedoms shown in Fig 1.

Figure 3. The mechanism of proposed interface;(a): overall view, (b) side view

3 VEHICLE TELEOPERATION

In general, the proposed interface can be matched to varioustypes of vehicles including differential-drive based vehicles, and

car-like vehicles. In addition, with the proposed interface a novelpossibility to match the proposed interface to differential-drivebased vehicle. This section proposes a matching strategy which

makes driving a mobile robot the same as driving a vehicle.Usually, the rotational velocity of mobile robot is controlled

based on a reference position of a masters joint. Conversely, inour proposed matching strategy, the angular position of mobilerobot is controlled based on the position of the center axis of the

proposed interface. This make driving a differential-drive based

HumanOperator

Slave(Targetvehicle)

Environment(Road, wind

etc.)

Master(Haptic

Interface)

CommunicationChannel

ml

mr

ml

mc

ml

axisleftaxisright

axiscenter

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vehicle the same as driving a vehicle. The proposed matching

strategies are possible with only the steeringwheel basedinterfaces (proposed interface and driving simulator) since there isno rotational axis in other types of masters (for instance, the

PhanTOM, Joysticks, and so on).There are four main strategies to match the proposed interface

to target vehicles called joystick-based steering with position-position mode, and joystick-based steering with position-velocitymode, and steeringwheel-based steering with position-position

mode, and steeringwheel-based steering with position-velocitymode. And operators may chose one of these when he or sheoperate a vehicle from a distance.

Forjoystick-based steering with position-position mode, Fig.Fig. 4 shows the possibilities of matching the position of

axisleft and axisright of the proposed interface to

the angular position r and l of mobile robot. In this case, the

axiscenter is not used. Therefore, this matching strategy iscalled as a joystick-based steering with position-position mode.

This matching strategy can be expressed by:

=

000000

00

l

r

mc

mr

ml

mr

ml

k

k

(2)

where:

mlk , mrk are proportional gains.

ml , mr , mc are angles of axisleft ,

and axisright , and axiscenter of the proposedinterface.

r , l are angular position of right wheel and left


Figure 4. Joystick-based steering with position-positionmode matching strategy

For joystick-based steering with position-velocity mode,

Fig.ure 5 shows the possibilities of matching the position of

axisleft and axisright of the proposed interface to

the angular velocity r& and l& of mobile robot. In this case, the

axiscenter is not used but the positions of master treated asmobile reference angular velocities in mobile robot side.Therefore, this matching strategy is called as a joystick-basedsteering with position-velocity mode. This matching strategy can

be expressed by:

=

0000

00

00

l

r

mc

mr

ml

mr

ml

k

k

&

&

(3)

where:

r& , l

& are angular velocities of right wheel and

left wheel of the mobile robot.

Figure 5. Joystick-based steering with position-positionmode matching strategy

For steeringwheel-based steering with position-positionmode, the strategy shown in Fig. 6 can be used to map the

proposed interface to both mobile robot (with differential-drivebased steering) and car-like vehicle (single-axis based steering).In this matching strategy, the average angular position of

axisleft and axisright is mapped to the translationalvelocity (or position) of mobile robot, the angular position

axiscenter is mapped to the angular position of mobilerobot.

This matching strategy can be expressed by:

=

+

mr

r

mc

mlr

cm

mlrm X

K

K

0

02 (04)

where:

mlrK , mcK

are proportional gains

mrX : is the translational speed of the mobile robot

mr : is the total rotation of the mobile robot

ml , mr

, mc

are angles of axisleft ,

and axisright , and axiscenter of the proposedinterface.

r& , l& are angular velocities of right wheel and left


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Comparision of a joystick-based interface and proposed interface

0

5

10

15

20

25

30

1 2 3 4

Subject

Time(s)

Joystick

HuTion

(a)

Figure 10. Compare two interfaces; (a): Logitech Joystick

and proposed interface; (b): A joystick on a gamepad.

Figure 11 illustrates the comparison of the conventionalsteeringwheel-based interface with the proposed interface without

cornering feel. In this experiment, a virtual mobile robot was usedas a target vehicle. The conventional steeringwheel-basedinterface was a Logitech steering simulator with force-feedback.The force feedback in the steering simulator was based on thesteering angle. The result has shown that the exploration time wasreduced in the case of conventional interface.

Figure 11. Compare two interfaces: Conventionalsteeringwheel and proposed interface without cornering feel

This is natural since the conventional interface isintuitive and customary to human operator explained in [1].However, there is a tradeoff between the proposed interface and

the conventional interface. Once the conventional interface waschosen as master device, then there is no way to reproducecornering effect with a single steering axis. In addition, the cost,

power consumption, space occupation of conventional interfacemay be an issue in some situations.

To investigate the advantages of cornering feel in the proposedinterface, we have tried experiments in which the cornering feel isdisplayed in the proposed interface using two single joysticks

( axisleft and axisright ) and the steering angle-basedforce-feedback in conventional steeringwheel-based interface wasmaintained.

Fig. 12 presents the comparison of two interfaces: Conventional

steeringwheel and proposed interface with cornering feel. Thisexperiment was conducted with a virtual mobile robot. The resultshave shown that the exploration time was reduced in the case of

proposed interface with all subjects. The reduced time in proposedinterface was because of the advantage of the cornering feel whichwas a kind of warning signal sent to the human operator when therobot traveled through a road corner. In addition, the corneringforce at single joysticks assisted the driver hands to smoothly

rotates the axiscenter thereby the steering motion wasconvenient and comfortable for him or her.

Comparision of a conventional steering interface (CSI) and

proposed interface with cornering feel (PI-CF)

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7

Subject

Explorationtime(s)

CSI

PI-CF

Figure 12. Compare two interfaces: Conventional

steeringwheel and proposed interface with cornering effect

Figure 13 is the number of collisions duringteleoperation of a real mobile robot in two cases: PhanTOMOmni and the proposed interface. The result shows that thenumber of collisions is reduce when the proposed interfaceis used as the master device.

Figure 13. With proposed interface, there are fewercollisions

5 CONCLUSION AND FUTURE WORK

We have demonstrated various matching rules to match theproposed interface to various configurations of target vehicles.

These possibilities help system developers freely chose a rightmatching strategy accordance with operating conditions of thetarget vehicle which is controlled by the operator.

The proposed mechanism of mater device was designed toimprove teleoperation performance, and efficiency. The

possibility of proposed architecture has been tested in bothcomputer based semi-experiments and real-vehicle based

experiments. The results have shown that the developed interfaceis sufficient and suitable for wheeled and tracked vehicleteleoperation and control. And the proposed interface can be

mapped to various target vehicles using different matching rules

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which are benefit and easy to be applied to different types of slave

configurations.Experimental results also have shown that it is possible to

display obstacle information to human operator using the

proposed interface.In future work, numerous topics should be extended and

continued.- Study possibility of display other driving feels

beside cornering feel.

- Study mechanical design to reduce the weight ofthe proposed interface.

- Develop an embedded controller for the proposedinterface.

- Make plan to manufacture mass production, andexhibition, and commercialization.

REFERENCES

[1] Ba-Hai Nguyen, Jee-Hwan Ryu, Design of a Master Devicefor the Teleoperation of Wheeled and Tracked Vehicles.ISBN: 978-1-4244-7453-0, ICCAS2010, Seoul, Korea.

[2] Otto J. Rsch, Klaus Schilling, and Hubert Roth. Hapticinterfaces for the remote control of mobile robots. ControlEngineering Practice, Vol. 10 pp. 13091313, 2002.

[3] Terrence Fong, Charles, Thorpe, "Vehicle TeleoperationInterfaces"ISSN:0929-5593, Volume 11 , Issue 1, Pages: 9 -18, 2001.

[4] T. Fong, C. Thorpe, C. Baur, A. C. Schultz, and L. E. ParkerRobot as Partner: Vehicle Teleoperation with CollaborativeControl. In Multi-Robot Systems From Swarms toIntelligent Automata. Kluwer Academic Publishers, 2002.

[5] Hara, M. Matthey, G. Yamamoto, A. Chapuis, D. Gassert, R.Bleuler, H. Higuchi, T., Development of a 2-DOFelectrostatic haptic joystick for MRI/fMRI applications.Robotics and Automation, ICRA '09. IEEE, 2009.

[6] Mooncheol Won; Grandpierre, T.; Fleutot, G.; Parent, N. Ajoystick driving algorithm with a collision stop feature on anelectric vehicle (Cycab). Intelligent Vehicle Symposium,IEEE, 2002.

[7] J. Yuh, Design and Control of Autonomous UnderwaterRobots: A Survey. Autonomous Robots, Volume 8, Issue 1,Kluwer Academic Publishers , ISSN:0929-5593, 2000.

[8] Sangyoon Lee, Gaurav Sukhatme, Gerard Jounghyun, Kim,Chan-Mo Park, Haptic teleoperation of a mobile robot: auser study. Presence: Teleoperators and VirtualEnvironments, Pages: 345 - 365, Volume 14 , Issue 3, MITPress , 2005.

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Haptic Interface for Intuitive Teleoperation of Wheeled and Tracked Vehicles Tien Si Nguyen Ba Hai

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