Mine Detection Robot and Related Technologies for Humanitarian Demining

Humanitarian Demining: Innovative Solutions and the Challenges of TechnologyFig 1 Mechanical demining equipmentFig 2 Tempest for brush cutterFig 3 Four legged mine detection robotFig 4 Mine detection robot cometThe total weight is about 1000kg, the size is 4m long 2

5m wide, and 0 8m high TheCOMET-Ill has 40 litter gasoline tank to continuously work for 4 hours and 700cc gasolineengine to generate DC power supply and to drive the hydraulicmotor So, the driving force is based on hydraulic pot14 MPa high pressure and theTherefore the COMet-III isra to make online mapping and trajectory planning, so thefully autordetection robot This kind of robot is the third type of deminingbased on advanced robotics, and is the futures approachensing and Access Control R&D for Humanitarian Mine Action project with our effort toHunt p a small vehicle for mine detection and clearance This small vehiclee(MHv), Specifically weoffreedom robotwhich is called as SCARAtoburied anti-personnelhave divided the project intera tasks to beooperation with Fuji Heavy Industries and Sato's group from Tohoku University, andArai's group from University of Electro-Communications has proposed a small teleoperatevehicle-based system The task of landmine detection is being undertaken by Sato's grouat Tohoku University, who are developing an array-style ground penetrating radar (SAR

e Detection Robot and Related Technologies for Humanitarian DeminingFig 13 DetectionFig 14 3-D mapping45 Trajectory Planning with 3-D ViDataThe trajectory planning is produced by the off-line Namely, at first, the 3-dimensionalfor the detection area like 1m x Im will be produced by means of the stereovision basednage processing, and then, the trajectory planning will be automatically done The targetHowever, the raw depth information from the stereovision camera contains large datavolume and also noise This large volume of data is inconvenient for the trajectory planning

Therefore, a working depth information f(r, nn)has been generated from the original depthvision camera after sampling it at a grid interval dgThus, the working depth information f(ml, z) can be written as1] and n2 are assumed integers This working depth information f(nL, n2)on the gridthe trajectory planning algorithmthe trajectory of theting point Pa of the CMDe detectionparallel to thev, and vo change the velocities of the pointground surface However, during the experiment the velocitiesDuring the trajectory planning, first the position and attitudehead aredecided on each grid point of fnm, n2); then these discrete pointeby straight lines to generate a continuous trajectory The folsatisfied during the trajectory planning1 The sensor head keeps itself approximately parallel to the ground surface

Humanitarian Demining Innovative Solutions and the Challenges of Technology3n scanningscanningFig 15 Trajector451 Decision of Attitude anglesThe target attitude angles a and a, of the sensor head that fulfill the first objectiirlier can be obtained from the depth information as the inclinations of the grourThe X, axial inclination at the grid point (nl, 12)of the ground surface is decided by the least6e is similarly decided Where ks is defined as an inclination coefficient of determinationHowever, thet attitude angles are decided inOne of the rethe movable ranges of the mechanism

Another one is the limitts bind ary between each grid point that consider the passing velocity, Dr and ty, of the pointlimits of the attitude movements er and a are shown below Where amAx shows the452 Decision of Length of Link 3Length I3 of Link 3 that fulfills the second objective stated earlier is decided with the attitudPapoint of the ball joint Po is Ps=l,de, n, d, Pe -d, -Is Where the fixed height of the pointPa is assumed to be p moreover the distance between the point p and the point pa in the

e Detection Robot and Related Technologies for Humanitarian Deminingumed to be dg Where position S at the center point S on thebottom is as follows with attitude vectors Xs and Y, on each grid pointWhere Is is defined as the distance between the point Pa and the point s At this time, all thehead's bottom kece Iugr to theurface, Therefore maximum length I3 is decided as filled above Howeve15the movable range of the mech453 Re-decision of Length of Link 3this trajectory planning targets at minefield, the length ls of Link 3 is decided againso that the sensor head does not touch the ground surface in spite of the delay is caused inach response of the LinksOn the im grid point of the trajectory that XY-stage passes, the position of theheaded to be a(, a (i)and the length of Link 3 is assumed to be b(n the present research, the Cmd does the following three operations at thetume1

Attitude changes of the sensor head3 XI and Yo axial motions by XY-stageHere the length ls(of Link 3 is decided again so that the CMD safely accommodate the timedelay caused by these three operations Here, these three operations are assud to be2 mpleted by the arrival time dy/'us, dy/uy to the next grid pointe length l(o) is decided again so that all the points on the sensor head s bottomdelay of thed However, l3() is decided in the restrictionmovable range of the mechanism and the limits of the expansions ldr and lythat consider the passing velocity, Dx and Dy, of the plimits of thelax and lay are shown below Where UMAX is assumed the maximum expansioelocity of link 3Figure 17 showenerated target trajectory at the center of the

248Humanitarian Demining Innovative Solutions and the Challenges of TechnologyGroundFig 16 Decision200200Fig 17, Trajecto46 Experiments ofFig

18 3-D range information of the detectioacquiren the experiment and the target trajectory is generated using themethods stated earlier Here each control input to the motor drivers of the CMD isgenerated with PID controller of feedback control system so that each expansion of theto the target trajectory Where the sampling frequency is taken as 50 HzMoreover, each gain of the PID controller is shown in Table 3, and each parameter in theajectory planning is shown in Table 4

e Detection Robot and Related Technologies for Humanitarian Deminingg 18 Detection area for experimentTable 4 Parameters of trajectory gTable 3, Gain of pid controlloFigure 19 showed the generated targettory and the resulthead's bottom in the experiment Fig 20 showed the time change of the vertical minimal gapbetween tlr head's bottom and the ground surface

Fig 20 shows not real data, buthe final data after signin the PC In addition, these spike peaks arthe discrete data like Fig 16 Moreover, the target trajectory and the response of eachexpansion of Link 1, Link 2 and Link 3 from the experiment beginning for four seconds aremm]-200-20Fig 19 Trajectory of sensor head

Humanitarian Demining: Innovative Solutions and the Challenges of TechnologyM20Fig 20 Gap between sensor hhead and ground surface(a)Li(b) LinkLink 3Fig 21

Trajectory responses of linksthe detection work and thge rha the safetthout contact with the ground surface has been achieved The safety allowance definedthis experiments Mr each link has an excellenttrajectory following performance with a small overshoot and delay respectively as shown in47 Methods of Estimating the position of Buried LandminesEstimating the position of the buried landmines with the data of landmine detection sensorsis important in detection work bdetection robots The metal detector usedresearch has a property that the frequency of the output changes before and after the metal

e Detection Robot and Related Technologies for Humanitarian Demininga fre m hehe Xh axis, anda positive value when a landmine exists on the left side from the center of the sensor headThe position of the buried landmine is estimated with the processedtput of the metal detectorThis section shows the method of estimating the buried position thatof the detection area with only one buried landmineeach X, axially scanning, the strength of the metal reaction: m; and candidate position of theburied landmine: [ ri yi] are decided with the output of the metal detector After all(Nbanning finished, the estimated position of the buried landmine is decided with eachrength of the metal reaction and each candidate position of the buried landmine as feWhere in the i scanning, the candidate position of the bilandminehe middle point of the positions in which the metal reactions pass the threshold vav]orValv along the Xb axially with keeping the output incIn addition, the strength of themi is assumed a difference between the maximum and minimum values inmed that va02 V and N=I,/yd+ 1 in this researchThe candidate positionFig 22 Definitions of the candidate position(im scanning4

8 Experimentetection area(x ly)of sands shown in Fig 18, and thelandmine detection experiments by the CMD are conducted The position of the burilandmine is estimated with acquired data of the metal detector, and effectivennd attitude control of the sensor head to landmine detection performance is verified Herethe control method is assumed same to the experiments of trajectory tracking in section 464rimental ConditionThree kinds of trajectordefined in this experiment to verify effectiveness of the gapnd attitude control to landmine detection performance and they are compared, Where Case

e Detection Robot and Related Technologies for Humanitarian DeminingGPR) Ouwill be mounted on and the mine clearance manipula2 State of the art of teleoperated mine detection by vehicle Mounted mineConventional vehited mine detector systemsachieve a detection swath typically 2-4m wide Some systems employ more than onetechnology These systems, while being very usefcomplex and inflexible A httor, on the other handle to side while moving forward toground The operafollow the groundprofile with the detectorclose to the ground without hitting the ground orIso vary the wide of sweep to suit a particular situation, and isually not limited by terrain

However the manual methodmanpower-intensive, and stressful to the operation who, as a result, can perform this taskonly for short periods at a time As well, the task is monotonous and at timesCanadian Center for Mine Action Technologies (CCMAT)obotic device capable of autonomously moving a mineetection seer natural ground surfaces including roads andse the safety of theperso

nnel performing mine detection As well, this will provide a more flexible and lessexpensIve wping surfaces such as roads and fields than systems which employstatic array of a vehicle-mounted systems Although several vehicle-mounted systems areprotected against conventional antitank mines, they still may requireehicle toneutralize antipersonnel and tilt-rod mines For the system proposed by CCMaT, therement for protection will be much reduced primarily becausenead of the vehicle without the sensor contacting the ground(GPR)and infrared and ultravioletras The vdid well in detecting antitankmines, but had difficulty identifying antipersonnel mines and proved very complicatedetection system(SAMS) The SAMsreduce the threat to deminers btely detecting, marking and allowsiebel Metal Detection Array SAMSmark, and map buried mines using a metal detection array and differential GPSlocation equipment under semi-autonomous remote control

Humanitarian Demining: Innovative Solutions and the Challenges of TechnologyFig 5 Robotic Scanner mounted on teleoperated Fig 6 Vehicle Mine Detector(VMMD)[6]another Vehicle Mounted Detection System(VMDS) The VMDS concepbased on a commercial skid steer chassis modified to incorporate a remote controlpability

The VMDS sensor package consists of a 2m wide Sciebel metal detection arrayThermal-Neutron Analysis(TNA)sensor, and an infrared sensor The meter array detectsetal objects in the vehicles path, while the TNa indicates those targets that containexplosive In testing, the meter detectioay performed extremely well The TNA foundmost AT mines, but had difficulty identifying AP mines and proved very complicated to3 Concept and Implementation of Mine Hunter Vehicle(MHV)ng in theection and clearance This small vehicle is nameder Vehicle(MHv)is equipped with mine detection sensors The general design considerations were as follows;n is easy()The weight of the main part of the vehicles is 1100kg-1500kg(4)It has an environment-proof nature, able to carry out a certain operation in the climate of(5)The vehicle can climb up and down slopes in mountain regions(6)The vehicle has durability against blasts from antipersonnel m()A reliable control device should be developedlope climbing capability, and spin turn()Durability and reliability test of an engine sy(4)Development of the axle whichily fitted withtiresty and reliability test of bulletproof equipment of an anti-personnne leve

e Detection Robot and Related Technologies for Humanitarian Demining(6)Durability and reliability test of the protection-against-dust nature which preventsasion of minute sand etc into flexible regions(7) Development of a reliable controlremote control andarm The drivediesel engine and a HST(Hydraulic Static Transmission) system Fourmendenrsached to the front right, the front left, the back right, and theback left The engine was selected to be applicable to the 2,000m high elevation inAfghanistan The left-hand sidler(front, rear) and right-hand side")have a separate hydraulic pump and the hydraulicother

Furthermore, MHV crawlers can rotate in #25 degrees centerind surfaces decreasednegotiate irregular ground and ascend and descend sloped ground Changing betweenrs and tires can be down easily by removing eight bolts, like changing a tire ofrmal car, a high-strength steel plate of 4, 5mm was attached in front with the bolts, Therotation part of the axles are bush bearings strong against shock and do not requireer in order to prevent sand and dust from invading the bearings, oil sealse attached to both sides Even if the axles are submerged in water, there will be no leakol device consists of modules which include the controller for hydraulic pressure, aproportionality electromagnetic valve driver, a remote control, image transmissionquipment, manipulator control equipment and the controller equipment of a mineailure, inderation of maintenance naturemade possible by module provision, The body became heavier as a result of strengthening,terproofing, protection against dust, and bulletproofing As a result, the targetweight limit was set to 1,600kg The engine power is 39PS, and the hydraulic pressure180kgThe designaccuracyAHV is as follows:of(2) Reduction gears were made into the plunocent rucksack system instead of a harmonic3)The sensor arm itself has a waterproof level of IP30n, the wholeressed with the jacket and waterprrder to always keep the direction of a mine detecnchronization with the(5) The SCARA arm has four-degeree-of-freeddegree-of-freedom are horizontal,one is the perpendicular, and one is the yaw of the seAlso they are driven by AcThe maximum payload is 40kg Each arm lengt

Humanitarian Demining: Innovative Solutions and the Challenges of Technology10 m/min and repetition positioning accuracy is tlmm in the horizontal direction#lmm in the perpendicular direpayload size is 400mm x 400mm x 400mm, and the SCARA arm full(8)GPR and a metal detector are installed at the tip of the SCARA arm, with gap controlused for the metal detector andused for the gPcontrol for therm control, and the mine detection sensor, Figures 7 and 8 show the field test in Sakaidty, Kagawa prefecture in March, 2006 Also, the performance of MHVMarch 2007

Croatia3到manipulatorAfter this, the controlled metal detector installation schedule on mhv is explained in detaildevelopment in theclearance system is described, focusing on the robotIn particularachieved theeasonable performance of a 6-degree of freedom robot with multi-function tool bynonlinear control based on"LOOK AT TABLE scheme or control theory scheme and alsothe master- slave hand4 Controlled Metal Detector Mounted on mine detection Roboonsidered as thereliablrs for mine detectiodetection perfthe metal detectors is highly dependent on thedistance between the sensor heads and the buried landmines Therefore, the landminece of the metal detectors could be substantially improved if the gap andhis functionbe performedwhere theheadaccurately follow the ground surface maintaining almost uniform gap between the groundsurface and the sensor heads by controlling the gap and attituheads, Fewmine detection robots that have thegnize ground surface and can control

e Detection Robot and Related Technologies for Humanitarian DeminingHowever, to the best of the knowledge of the authorssearch work has beenture that quantitatively addressed the redetection performance and controlling the gap and attitude of the sensor head to the groundmay have substantial amount of vegetatioImage-processingthe CCDoperation of the CMD in vegetated minefield inimpact with the ground can be avoided The Cmd then tracks the generated trajectectory-tracking controller so that theffectiveness and the impact related to the gap and attitude control on the mineperformance of the CMD have been demonstrated by experimental studsection 43 The description of stereovision camera has been presented in section 44 Thedescription of trajectory planning has been presentesection 45 The results ofexperiments of trajectory tracking have been presented in section 46 The results of48 The soIn view of the above, authors research group has developed a Controlled Metal Detector(CMD) having 3-DOF for any arbitrary positioning of the sensor head The CMD system cangenerate 3-D high-speed mapping of the ground surface and can generate trajectories of theG-D stereodely used for 3-D mapping and robotics(Clark, F et al

2007),(Rochaa, R et al 2005),(Xiao, D, et al 2004)ful sensing capability than other range sens42 Controlled objectof the tweactor and a 3-dof mechanicapulation mechanism drctric motors Themposed of the main body of the CMD, twoPC3-D stereotrform the two-dimensional motionthree motorized linkages(Link 1, Link 2, and Link 3) The bathe rotational motion into translation motion The gyratioin vertical direction of thelengths of the Link 1Link 2 and Link 3 The right-handed coordinate system yOt11spectively) are measured withders installed in each link the calculation methoddescribed in next section

Humanitarian Demining: Innovative Solutions and the Challenges of TechnologyThe CMD is mounted on the horizontal positioning arm of the XY-stage at the point Pthe horizontal positioning arm of the xY-stage, it is possible to make theheadtoriested with 3-D stereono metallic parts within 600 mm from the sensor head; this practically eliminates any chanceof interference on the metal detector Table i shehe specifications of the CMDXY-stageFig 9 Overview of CMD systemoder[ DC MotorLDetFig 10

Architecture of CMD systemFig 11 Configuration of CMD

e Detection Robot and Related Technologies for Humanitarian Deminingis a ditch on the ball joint Pa The geometrical relationship between the lengand the1 10 Pitch, RollTable 1 Specifications of CMDpitch angle O, roll angle ar head shown in Fig 12 In the CMD system, in orderto ensure that the sensor head follows the ground surface without any collision, theta

Then the changes in lengths I1, z are calculated from the inas shown below()and(2)(1214+2/sL sin(6 -arctanMoreover, the direct kinematics is as follows6l,“+2,l4-2le arctanWhere s andengths of links, and L12 Moreoverde vectors x yhead are defined as Xe with attitudengles 6 a4 Ground Mapping with 3-D Std Bumblebee( Point Grey Research Inc ) has beenD stereovision based ground mapping This stereovision cama parallelpecifications of thend the optical axis of the leftthe x axis and the ataken the horizontalaxis and the verticalthe leftdefined as thedinate system Od

244Humanitarian Demining: Innovative Solutions and the Challenges of Technology(a) Pitch of CMD)Roll of CMDn algorithm searches fspondence points between the lefthe right image acquired with the stereovision camera by the template matchin the right and left images as followsfBWhere the posiof correspondence points p and pon the right and left images aredefined as (a, yr),(rn, y,)As a result, geographical features information in the camera coordinate system is acquiredTherefore, depth information f(r, y) on the ground surface in the base coordinate system isgenerated with the coordinatersion

Here a photograph of the detection areaample is shown in Fig 13, and the 3-D geographical features map is shown in Fig 14Device size[mm]160(W)×40(H)×50)Weight [glBaseline [mm]Focal length [mmPixels320(H)×240(V)angle [deg]Table 2 Specifications of stereo