基于慧魚(yú)組件的多功能物料運(yùn)輸車機(jī)器人設(shè)計(jì)起升機(jī)構(gòu)結(jié)構(gòu)部分設(shè)計(jì)【履帶式災(zāi)害救援機(jī)器人設(shè)計(jì)】,履帶式災(zāi)害救援機(jī)器人設(shè)計(jì),基于慧魚(yú)組件的多功能物料運(yùn)輸車機(jī)器人設(shè)計(jì)起升機(jī)構(gòu)結(jié)構(gòu)部分設(shè)計(jì)【履帶式災(zāi)害救援機(jī)器人設(shè)計(jì)】,基于,組件,多功能,物料,運(yùn)輸車,機(jī)器人,設(shè)計(jì),機(jī)構(gòu),結(jié)構(gòu),部分,部份,履帶式,災(zāi)害 1 Robot e kinematic analyzed ol , and DOI: obots, 1 more ous posed, dif bombs, orbit endangered H208511H20852. So, it is expected that mobile robots, whether autonomous or tele-operative, play a more important role in dif- ferent fields of human life. However, in a mobile robotic system, dynamic based dynamics, research Aftershocks secondary and while collaborative robots their building man being victims communications thermal, less, mechanism is addressed. Then, the robot control system is de- scribed. Finally, slip coefficients are identified and validated by various tests to improve the system tracking performance. in manuscript by Journal Downloaded 02 Dec 2009 to 222.190.117.200. Redistribution subject to ASME license or copyright; see http:/www.asme.org/terms/Terms_Use.cfm forces affect the motion of the base and the manipulators, on the action and reaction principle. Therefore, kinematics, and control of such systems have received extensive attention H2085125H20852. Earthquake is a natural incident, which threatens human life. occurring a while after the main earthquake cause collapses and may take victims away from the search rescue personnel. In order to minimize the risks for rescuers, increasing victim survival rates, exploiting fielding teams of robots is a good alternative. The mission for the and their operators would be to find victims, determine situation, and then report their findings based on a map of the H208516,7H20852. This information will immediately be given to hu- rescue teams. Further expectations of rescue robots such as able to autonomously search collapsed structures, finding and ascertain their conditions, delivering sustenance and to the victims, and emplacing sensors H20849acoustic, seismic, etc.H20850 are ongoing research subjects. Neverthe- the basic capability of rescue robots is their maneuverability ResQuake has great capabilities for moving in unstructured envi- ronment, on rough trains, and even climbing stairs, with a user- friendly operative interface. Its performance has been demon- strated in the rescue robot league of RoboCup 2005 in Osaka, Japan, achieving the second best design award, RoboCup 2006 in Bremen, Germany, achieving the best operator interface award, and RoboCup 2008 in Suzhou, China, achieving the second best award for mobility. 2 Mechanism Design There are three major categories of search and rescue robots in terms of their locomotion system, i.e., wheeled, tracked, and 1 Corresponding author. Contributed by the Mechanism and Robotics Committee of ASME for publication the JOURNAL OF MECHANICAL DESIGN. Manuscript received July 21, 2008; final received May 7, 2009; published online July 20, 2009. Review conducted Ashitava Ghosal. Fig. 1 ResQuake in different conditions; left folded tracks, right extended tracks climbing up a ramp uneven surface of Mechanical Design AUGUST 2009, Vol. 131 / 081005-1Copyright 2009 by ASME S. Ali A. Moosavian Associate Professor e-mail: moosaviankntu.ac.ir Arash Kalantari Graduate Student e-mail: Hesam Semsarilar Graduate Student e-mail: Ehsan Aboosaeedan Graduate Student e-mail: Ehsan Mihankhah Graduate Student e-mail: Advanced Robotics and Automated Systems (ARAS) Laboratory, Department of Mechanical Engineering, Khaje Nasir Toosi University of Technology, P.O. Box 19395-1999, Tehran 19991 43344, Iran ResQuake: Rescue The design procedur analysis, manufacturing improvement are discussed. fined, and various mechanisms Choosing the appropriate detailed to develop each component is sented. Then, the contr the master processor slip coefficients of tracks system tracking performance. cue robot leagues. H20851 Keywords: mobile r slippage estimation Introduction Mobile manipulators, which consist of a platform and one or manipulators, have an unlimited workspace. Therefore, vari- legged, wheeled, tracked, and flying systems have been pro- and successfully put into practice. Such systems are used in ferent kinds of fields such as fire fighting, forestry, deactivating toxic waste cleanup, transportation of materials, space on- services, and similar applications in which human health is A Tele-Operative of ResQuake as a tele-operative rescue robot and its dynamics procedure, control system, and slip estimation for performance First, the general task to be performed by the robot is de- to form the basic structure of the robot are discussed. mechanisms, geometric dimensions, and mass properties are and dynamic models for the system. Next, the strength of to finalize its shape, and the mechanism models are pre- system is briefly described, which includes the operators PC as the laptop installed on the robot as the slave processor. Finally, are identified and validated by experimental tests to improve the ResQuake has participated with distinction in several res- 10.1115/1.3179117H20852 tele-operative, locomotion mechanisms, control architecture, in destructed areas, which thoroughly depends on their locomo- tion system and their dimensions. Various rescue robots were de- signed and manufactured so far H208518,9H20852. This paper presents an illustrative description of the ResQuake project at Khaje Nasir Toosi University H20849KNTUH20850, as shown in Fig. 1. First, designing procedure for the locomotion mechanism will be detailed, and the system dimensions and related parameters are determined. Next, the system kinematics and dynamics is dis- cussed, and the sequence of stress analysis for each member of the legged flat due climbing T move systems smaller H20849 modeling the quires expensive. the comotion vented mechanism while rain. cue ronment, ceilings situations, the pends passageway ways destructed up of Fig. same of 081005-2 Downloaded 02 Dec 2009 to 222.190.117.200. Redistribution subject to ASME license or copyright; see http:/www.asme.org/terms/Terms_Use.cfm robots. Wheeled robots could be considered for searching areas. Developing the autonomy for these systems is easier to their simple dynamics. A wheeled robot is also capable of obstacles with a height smaller than their wheels. racked robots are used mostly because of their great ability to on uneven terrains. Figure 2 shows wheeled and tracked facing the same obstacle H20849stairH20850. It can be seen that a tracked robot has the same capability. Legged robots usually possess high degrees of freedom DOFsH20850, and thus, high maneuverability. Consequently, dynamics and stability of such systems is more complicated than former types. Besides, implementation of such systems re- numerous actuators and sensors, so their control is more It should be also mentioned that with a combination of two wheeled and legged mechanisms, advantages of both lo- systems can be preserved while shortcomings are pre- H2085110H20852. In a hybrid wheel-legged mechanism, wheeled can support the weight of the legged mechanism, the legged mechanism can move the robot on a rough ter- Regardless of the type of locomotion system, the size of a res- robot is also an important issue. In a destructed indoor envi- some obstacles may exist such as collapsed walls or that cannot be easily passed by usual systems. In such the robot should search for a bypass or a way between obstacles rather than climbing over them; that definitely de- on its size. A relatively small robot can easily pass a narrow and continue its search. It should be noted that stair- are an inseparable part of an indoor environment. Whether or not, a rescue robot should have the ability to climb and down stairways in order to search the whole area. In order to compromise between the two contradictory aspects providing a small robot with high maneuverability, a tracked 2 Two types of locomotion systems encountering the obstacle Fig. 3 a Minimum length for tracks radius of a simple track robot / Vol. 131, AUGUST 2009 mechanism has been developed for ResQuake. This mechanism includes a main body H20849baseH20850 with two expandable tracks H20849armsH20850. This arrangement enables the robot to resize depending on the situation it encounters. Accordingly, these tracks should have a minimum length to prevent loosing its balance, and having a steady movement on successive stairs without extra vibrations, as shown in Fig. 3H20849aH20850. On the other hand, lengthy tracks such as those of a simple track robot will require a wide area for turning, as shown in Fig. 3H20849bH20850, which is rarely available in a destructed environment. 2.1 Expandable Tracks (Arms). The structure shown in Fig. 4 enables the robot to expand the length of its tracks to pass through obstacles. On the other hand, when the robot is going through narrow passages and needs to be rather small, the front tracks can be folded. This helps with reducing the turning radius as well. Folding arms was the original idea, developed to over- come the aforementioned contradiction. This concept has been improved to a system with two pairs of arms at both sides of the vehicle, as shown in Fig. 4H20849bH20850, to reduce the length of the robot with folded arms while the expanded length fulfills other requirement. Another advantage would be the symmetry of the structure, which enables the robot to move equivalently in both forward and backward directions. This ar- the robot and b minimum turning Fig. 4 a Preliminary design of just front tracks arm and b improved design with two pairs of arms front and rear Transactions of the ASME rangement width order H20849 stretched traction. increase of simply second dependent. configurations such these arm, chain main chain, be attached placed does main mechanism will gap track the small Fig. robot Journal Downloaded 02 Dec 2009 to 222.190.117.200. Redistribution subject to ASME license or copyright; see http:/www.asme.org/terms/Terms_Use.cfm facilitates turning in a confined space. Next, the arms are placed in the same plane to reduce the robot H20849Fig. 5H20849aH20850H20850. Finally, another joint is added to each arm in to use an extra area between the arms when they are folded, Fig. 5H20849bH20850H20850. Therefore, the tracks on each side of the robot are into three parallel planes, which provide a more efficient Adding four independent H20849activeH20850 joints to the system would the number of actuators and consequently the total price the system. Therefore, a planetary gear set has been used to transmit the power of the main joint of each arm to its joint. So, rotation of the two parts for each arm will be The gear ratio is obtained, considering two desirable of the arms; H20849iH20850 fully stretched and H20849iiH20850 fully folded, that the arms can move, based on a desired plan between two configurations H20849Fig. 6H20850. As shown in Fig. 6, for a H9266/2 rad rotation of the main part of the second part should rotate more than H9266 rad. The gear with such performance should be a planetary gearbox. The part of the first arm plays the role of the arm in the planetary which is directly powered by a motor. The sun gear should attached to the main body of the robot, and the planet gear is to the second part of the arm. A pair of medium gears is between the sun and the planet where the diameter of gears not exceed a given threshold, which is the diameter of the wheels of the tracks H20849Fig. 7H20850. Another advantage of this is that the center distance of the two joints of the arm remain constant during its rotation. This enables us to fill the between the main track, and the arm with another track. This is used to transmit power from the main part of the tracks to second part on the arm. Helical gears are chosen for the planetary gear set, due to their backlash and higher strength of gear tooth comparing with 5 a Making the tracks collinear to reduce the width of and b final mechanism chosen for the tracks Fig. 6 The path for motion of the arms Fig. 7 Planetary gear chain of Mechanical Design spur gears H2085111,12H20852. The angular velocity of the arm should be less than 24 rpm. The motors output velocity is 3000 rpm. Hence, the velocity ratio between the motor and the link should be ap- proximately 1000. A combination of a three stage planetary gear- box H20849constructed right at the motor shaft where the angular veloc- ity is relatively highH20850 with a ratio of 3:1 at each stage, and a worm gear set with a ratio of 30:1 provides the desirable ratio in a limited available space H20849Fig. 8H20850. A dc motor drives the tracks at each side of the robot. 2.2 Tracks. The traction of the locomotion system strongly depends on the friction between the track pieces and the surface on which the robot moves. Therefore, the material and the shape of the track pieces are of great importance H2085113H20852. On the other hand, the tracks should also bear a reasonable tension. Designed tracks are made of two main parts. A basis of chain-sprocket pro- vides the system with sufficient tensile strength, and tooth shaped pieces made of latex fills the gap between the chain and the sur- face to create the required friction. Metal chains have been modi- fied by replacing pins of the standard chain with longer pins, and the latex grousers are mounted directly on them. Figure 9 shows modified chains and how the grousers are mounted on these pins. One of the most important problems caused by base movement, when the system undergoes a fast maneuver or tries to climb a slopped terrain, is the instability problem or tipping over H2085114H20852. Noting this, two major advantages are obtained by including a suspension mechanism. The suspension system was designed by containing two sur- faces on the main body, and then attaching them by a revolute joint H20849Fig. 9H20850. A pair of linear springs limits the angle of rotation and makes the system remain at a desired position when no extra forces are applied. It should be mentioned that the use of dampers Fig. 8 Final designed arrangement for the arms Fig. 9 Top: latex pieces fixed on the chain; bottom: basic structure of the suspension system AUGUST 2009, Vol. 131 / 081005-3 was the springs. mechanisms, components dard parts. the merous not used dimensions summarized 3 can in tioned the coordinate 11 lows: Parameter C CL C d d d d Gap1 Gap2 H H L L 081005-4 Downloaded 02 Dec 2009 to 222.190.117.200. Redistribution subject to ASME license or copyright; see http:/www.asme.org/terms/Terms_Use.cfm not needed because the friction of the sliding bearings used as so-called joints was enough to limit any extra shaking of the 2.3 Final Dimensions. Finishing the design of locomotion the dimensions are to be determined. Some of the like metal chains and sprockets are available as stan- parts, so that other dimensions should match their counter- Besides, the overall size of the robot and the formulas on gear chains must be considered in the calculations. Since nu- equations govern these factors, an optimized solution is reachable by manual calculations. Thus, MATLAB has been to find the desired values from a set of equations. The main considered in this procedure are shown in Fig. 10 and in Table 1. Kinematics Analysis A mobile rigid platform has three DOF in a flat plane, which be defined either in the body coordinate frame c:H20853x,y,H9278H20854,or the inertial coordinate frame C:H20853X,Y,H9272H20854. It should be men- that the body coordinate frame is fixed to the main body of robot with the x axis along with the tracks, while the inertial frame is fixed to the plane of motion as shown in Fig. H2085115,16H20852. The direct kinematics is developed in the main frame as fol- Table 1 Dimensional parameters of robot Value H20849mmH20850 Description m 292.1 Center to center distance of main sprockets 127 Center to center distance of link a 106.2 Center to center distance of arm sprockets G1 43.9 Pitch diameter of the sun gear G2 43.9 Pitch diameter of the first medium gear G3 41.6 Pitch diameter of the second medium gear G4 39.3 Pitch diameter of the planet gear 5 Gap between folded arm and main body 9 Gap between folded arms track 14 Height of track parts total 260 Height of the robot total F 400 Length of the robot with folded arms total O 760 Length of the robot with open arms Fig. 10 Main lengths for determining / Vol. 131, AUGUST 2009 H20849X ,Y ,H9272H20850 =H9024H20849H9275 r ,H9275 l H20850H208491H20850 which relates the velocity components of the main body to the angular speeds of the right and left tracks. The speed of the right track is calculated by V r = rH9275 r H208491i r H20850 = rH9275 r i r H208492H20850 where r is the driving wheel radius, H9275 r is the angular speed, and i r is the slip coefficient of the right track that is defined as i r = V t V rr V t =1 V rj V t H208493H20850 where V t is the theoretical speed, and V rr is the real speed of the right track. Equations H208492H20850 and H208493H20850 can be similarly rewritten for the left track. On the other hand, the velocity components for a point like F on the robots axis of symmetry can be obtained as x = cbH20851H9275 r i r +H9275 l i l H20852 y = l G H9278 cbH20851H9275 r i r +H9275 l i l H20852 tanH20849H9251H20850 H9278 = cH20851H9275 r i r H9275 l i l H20852H208494H20850 where b is equal to the half width of the robot, c is a constant equal to r/2b, and H9251 is the slip angle of the robot, which has a the other dimensions Fig. 11 The robot moving on a circular path Transactions of the ASME nonzero value in the presence of side slippage. Lateral or side slippage happens mainly due to the centrifugal force exerted to the robot when moving on a curved path with a relatively high speed. Maximum ceed Besides, results robot glected, It terclockwise the From Replacing which grated configuration tion Substituting sented where Keeping rotation It second Journal Downloaded 02 Dec 2009 to 222.190.117.200. Redistribution subject to ASME license or copyright; see http:/www.asme.org/terms/Terms_Use.cfm longitudinal speed of the chosen platform does not ex- 0.3 m/s, which will result in a negligible centrifugal force. the design of the tracks treads, as explained in Sec. 2.2, in a large lateral friction force, which in turn helps the to not slip laterally. Therefore, the lateral slippage is ne- and Eq. H208494H20850 is rewritten as x = cbH20851H9275 r i r +H9275 l i l H20852H208495aH20850 y = l G H9278 H208495bH20850 H9278 = cH20851H9275 r i r H9275 l i l H20852H208495cH20850 should be mentioned that Eq. H208495cH20850 yields a positive H9278 for coun- rotations. These components can be transferred into inertial frame F as X = x cos H9278 y sin H9278 H208496aH20850 Y = x sin H9278+ y cos H9278 H208496bH20850 H9278 =H9278 H208496cH20850 Eq. H208496H20850 we can write Y cos H9278 X sin H9278= y H208497H20850 from Eq. H208495H20850 in Eq. H208497H20850, yields X sin H9278+ Y cos H9278 l G H9278 =0 H208498H20850 describes a nonholonomic constraint. It cannot be inte- analytically to result in an algebraic constraint between the variables of the platform, namely x, y, and H9278. Equa- H208498H20850 can be written in the matrix form AH20849qH20850q =0 H208499aH20850 A = H20851 sin H9278 cos H9278 l G H20852 H208499bH20850 Eq. H208495H20850 into Eq. H208496H20850, direct kinematics can be pre- as d dtH20900 X Y H9272 H20901 = J H20875 H9275 r H9275 l H20876 H2084910H20850 J isa3H110032 Jacobian matrix as J = H20900 ri r 2 H20873cos H9278 2l G sin H9278 B H20874 ri l 2 H20873cos H9278+ 2l G sin H9278 B H20874 ri r 2 H20873sin H9278+ 2l G cos H9278 B H20874 ri l 2 H20873sin H9278 2l G cos H9278 B H20874 r B i r r B i l H20901 H2084911H20850 the first two equations of Eq. H2084910H20850 and displaying the matrix explicitly, we can write H20875 X Y H20876 = H20875 cos H9278 sin H9278 sin H9278 cos H9278 H20876 H20900 ri r 2 ri l 2 ri r l G B ri l l G B H20901 H20875 H9275 r H9275 l H20876 H2084912H20850 can be seen that if in Eq. H2084912H20850, l G is set to be equal to zero, the matrix will be singular. This is because all points for of Mechanical Design which l G =0