Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Design and Realize a Snake-Like Robot in Complex Environment

Design and Realize a Snake-Like Robot in Complex Environment Hindawi Journal of Robotics Volume 2019, Article ID 1523493, 9 pages https://doi.org/10.1155/2019/1523493 Research Article 1 1 1 1 1 Bingqi Liu, Mingzhe Liu , Xianghe Liu, Xianguo Tuo, Xing Wang, 1 2 Shibo Zhao, and Tingting Xiao State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, China Deyang Science and Technology Information Research Institute, Deyang, China Correspondence should be addressed to Mingzhe Liu; liumz@cdut.edu.cn Received 23 October 2018; Accepted 14 November 2018; Published 3 February 2019 Academic Editor: Gordon R. Pennock Copyright © 2019 Bingqi Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Aiming at high performance requirements of snake-like robots under complex environment, we present a control system of our proposed design which utilizes a STM32 as the core processor and incorporates real-time image acquisition, multisensor fusion, and wireless communication technology. We use Solidworks to optimize the design of head, body, and tail joint structure of the snake-like robot. The system is a real-time system with a simple-circuit structure and multidegrees of freedom are attributed to the flawless design of control system and mechanical structure. We propose a control method based on our simplified CPG model. Meanwhile, we improve Serpenoid control function and then investigate how dieff rent parameters aec ff t the motion gait in terms of ADAMS emulation. Finally, experimental results show that the snake-like robot can tackle challenging problems including multi- information acquisition and processing, multigait stability, and autonomous motion and further verify the reliability and accuracy of the system in our combinatory experiments. 1. Introduction Several disadvantages still exist in many cases and pro- totypes including shortcomings of mechanical structures, With the rapid development of science and technology, bionic unreliable control strategy, and algorithms [13, 14]. Therefore, robots, especially snake-like robots, have been widely used in a snake-like robot which adapts to changes in complex military, civil and space, and other eld fi s [1–5]. Robots can environment is proposed to overcome current problems in demonstrate advantages in camouafl ge and multiple degrees the snake-like robot design. In this paper, the prototype of of freedom, with which dangerous works can be completed the snake-like robot is designed in a routine of mechanical in a total and/or partial replace of people’s roles, such as design, motion control, signal acquisition, data transmission, investigation, search and rescue, patrol, pipeline inspection, simulation research, and prototype test, which owes small and space exploration. To strengthen advantages and usages volume, light weight, and multiple degrees of freedom. The of snake-like robots, many scholars have conducted active emulation experiment and prototype test adequately proved studies on the snake-like robots [6–10]. Leading Research that the stability of the snake-like robot is expected. Groups include the group led by Professor Hirsoe in Tokyo Institute of Technology (ACM R8), the robot team in 2. Overall Scheme Design Carnegie Mellon University (Uncle Sam), and the robot team in Michigan University (OmniTread). ACM R7 may bend its The snake-like robot studied in this paper mainly includes body gfi ure into a circle and rolls forward in a grass land like the mechanical structure, the control system, and the power a wheel [11]; Uncle Sam is categorized into a reconfigurable supply system (Figure 1). The mechanical structure consists genre of robots, which is extremely suitable in applications in of three modules: head, body, and tail. The control system ducts, slits, etc. [12]; OmniTread is skilled at climbing upward is composed of 3 main parts: a master control system, slave and able to crawl across pipeline with a diameter of 11 cm to control systems, and a monitoring system. The master system 24cm. is integrated in the snake head, which mainly undertakes 2 Journal of Robotics Snake-like robot Mechanical structure Control system Power supply system Snake head Snake body Snake tail Master control Slave control Monitoring Battery Voltage- module module module system system system module stabilized module Figure 1: Design diagram of the overall scheme. Figure 2: Assembly diagram of the snake-like robot. Figure 3: Design diagram of the snake body joint. the role of automatic detection of the external environment, lead to a more compact structure and high spatial degrees of and controls the slave control system by sending commands. freedom (Figure 2). Solidworks is employed to optimize the The slave control systems are distributed in body and tail, design of head, body, and tail joint structure of the snake-like completing the specific gait regulation and control. The robot. monitoring system is hosted in a phone APP, which realizes the monitor and display function of sampled information. 3.1. Snake Body Joints Design. Joint modules are modelled to The power supply system consists of a rechargeable lithium satisfy spatial requirements for lithium battery modules, the battery module and a voltage-stabilized module that meets slave control circuit boards, and the motors. The draw of the energy requirements for the entire snake-like robot. Each snake body joint is viewed by a planar figure as shown in joint incorporates such a power module in the snake-like Figure 3, where (A) is the link between the joints, to ensure robot. that the joints are to complete the angle of±135 degrees of rotation; (B1) and (B2) are horizontal and vertical motors; the two motors are integrated into a joint to narrow the snake 3. Mechanical Structure Design space to ensure the flexibility of the joints; (C) and (E) are the Traditional orthogonal structure requires orthogonal place- lithium battery and the fixed position for slave control circuit ment of joints, and each joint only has one motor [14]. board, respectively; (D) and (F) are the xfi ing holes for the This paper uses the method that requires two motors in longitudinal and transverse motors; (G) is the support for the orthogonal placement for each joint. This improvement will metal sheet of the snake body joint. Journal of Robotics 3 Figure 4: Design diagram of the snake head joint. Figure 5: Design diagram of the snake tail joint. 3.2. Snake Head Joint Design. The snake head joint is the 4. Control System Design core component of the entire snake-like robot. The draw The master control system is made up of a camera module, of the snake head joint is viewed by a planar figure as a laser ranging module, a temperature-humidity sensor, an shown in Figure 4. A motor (K) is placed in the longitudinal air pressure sensor, a thermal imaging sensor, and a CO position of head joint under the premise of horizontal sensor. Among them, the camera module and the thermal movement in snake head joint. The front of the snake head imaging sensor collect environment information and human joint is streamlined to reduce the resistance of the forward perception information and display them by images. The movement and to position the camera (H). At the same time, slave control systems coordinate with the master control the snake head joint is equipped with a lighting device (I) to system to control and adjust the snake-like robot’s movement work in a dark environment. The battery (J) is installed for gaits with the ZigBee wireless transmission mode. The slave the snake head portion. control systems generate PWM signals to drive correspond- ing motors. The monitoring system is equipped with WiFi 3.3. Snake Tail Joint Design. The draw of the snake tail and Bluetooth modules as communication channels with the joint is viewed by a planar figure as Figure 5. Taking their master system, which holds control and monitor tasks in the corresponding structures into account including the laser snake-like robot (Figure 6). distance measuring sensor (L), infrared heat source sensor (M), and the master control board (O), the temperature- humidity sensor and air pressure sensor are embedded on the 4.1. Master Control System Design. The master control system master control circuit board; additionally a small portion of consists of four main modules: a core processor, a wireless space is reserved for a CO (N) sensor. For the position case communication module, a camera module, and multisensors of the tail motor, its structure is right inversed to that of the (Figure 7). The master control system receives the control head motor. commands from the monitoring system and obtains data 4 Journal of Robotics Terminal WiFi video reception App Bluetooth module Monitoring system WiFi video launch Bluetooth module Zigbee Master control system of snake-like robot Laser Temperature Air Thermal Camera CO ranging and humidity pressure imaging module sensor module sensor sensor sensor Master control system Zigbee Zigbee Zigbee Execution Execution Execution unit unit unit PWM servo PWM servo PWM servo control control control Slave control system Figure 6: Design diagram of the control system. Figure 7: Circuit diagram of the master control system. from multiple sensors through the Bluetooth module. The coordinator. Meanwhile, the master control system sends monitoring system determines the motion gait of the snake- demands to the core processor in the serial interface mode. like robot according to control demands and displays the These demands drive motors to complete the corresponding sensor parameters on the APP. The master control system gait operation. In order to facilitate the movement of snake- uses the WiFi module to communicate with the monitoring like robots and meet the power supply needs, we select the system and obtain the image information of a RGB camera 7.4V lithium battery-powered solution, through RT9193 to in real time. The system is equipped with LED lights for convert from 7.4V to 3.3V for the control circuit board; at the camera so as to obtain the high-definition image in the the same time, a diode will enable 7.4V to lower down 6V, dark environment. The CC2530 coordinator communicates to ensure reliable operation of motors (Figure 8). with the Zigbee, via the CC2541 Bluetooth module to transfer multisensor data. 4.3. Monitoring System Design. The monitoring system is developed by Java based on the Android system. The control 4.2. Slave Control System Design. The slave control system interface of the host computer is divided into two interfaces: selects STM8s003f3p6 as the core processor. The snake-like the camera real-time acquisition in the first interface; thermal robot uses 6V-powered high-torque motors supplied by the imaging, gait control, and sensor detection in the second battery with 6V, 250mAh lithium battery, to ensure that the interface. The gait control consists of vfi e gaits: serpentine snake-like robot running lasts more than one hour. The mas- locomotion, creeping, lateral displacement, tumbling, and ter control system sends wireless instructions to the CC2530 terminal node in the slave system through the CC2530 climbing (Figure 9). Journal of Robotics 5 Figure 8: Circuit diagram of the slave control system. Snake-like robot Video sources Gaits control Sensor detection Air Temperature Laser Thermal CO Camera pressure and humidity ranging imaging sensor module sensor sensor module sensor WiFi Bluetooth Bluetooth transmission transmission transmission Real-time detection and display Serpentine Lateral Creeping Tumbling Climbing Locomotion displacement Bluetooth transmission debugging and control Figure 9: Logic diagram of the monitoring system. 5. Motion Control Design Equation (2) is obtained by simplifying (1): 𝜙 =𝐴 sin(𝜔𝑡+𝐵𝑖 )+𝛾 (2) There are three controls modes for snake-like robot: gaits control (GC) based mode [15], Serpenoid control function where𝜙 is the angle between joint 𝑖 and(𝑖−1) (𝑖= (SCF) based mode [16–19], and central pattern generator 1,2...𝑛 ),𝐴 is the amplitude of the joint angle when𝛾=0 , (CPG) based mode [20–23]. SCF and CPG are key focuses 𝜔 is the joint radial frequency,𝐵 is the initial phase of the in this paper. function,𝛾 is the deflection angle of the entire system, and (𝜔𝑡+𝐵𝑖) is the phase. 5.1. Serpenoid Control Function. Hirose proposed the Ser- According to (2), the condition𝑡= 0 and𝜙 =0̸ is penoid control function via (1) which imitates the movement not consistent with the actual requirements. Therefore, (2) is of nature snake from a long-term observation of snake transformed to guarantee𝜙 =0 and𝑡=0 as (3). behaviors [17]. −𝑡 𝜙 =(1−𝑎 )𝐴 sin(𝜔𝑡+𝐵𝑖 )+𝛾 𝑎≥1 (3) 𝑥 (𝑠)=∫ cos(𝑎 cos(𝑏𝜎+𝑐𝜎 )) As demonstrated in Figure 10, the transformation does not alter both minimum and maximum values over a long (1) time, except state differences in initial stage. This transforma- 𝑦 (𝑠)=∫ sin(𝑎 cos(𝑏𝜎+𝑐𝜎 )) tion does not affect the movement of the robot. 𝑑𝜎 𝑑𝜎 6 Journal of Robotics 1.5 The image of Eq.(2) The image of Eq.(3) Initial poin1 Initial point2 0.5 rad 0 −0.5 −1 −1.5 0 1 2 3 4 5 6 7 8 9 10 t (s) Figure 10: Contrast diagrams of the equations. CPG1 CPG2 CPGn-1 CPGn Xn-1 Yn-1 X1 Y1 X2 Y2 Xn Yn Figure 11: Convergence graph of CPG. 2.5 1.5 0.5 −0.5 −1 −1.5 −2 −2.5 −4 −3 −2 −1 0 1 2 3 4 Figure 12: Convergence graph of CPG. 5.2. CPG Control Mode. A chain network is included by 2n 𝑘 ,𝑎 ,and𝑎 are constants. CPG can converge if parameters 1 2 oscillator (Figure 11); the output of the distributed oscillator are properly choseninmodel (Figure 12). can provide movement control signals for the snake-like From Figure 13, it can be seen that the model exhibits dual robot. stable sine or cosine dynamics over time about x and y. In A single simplified CPG model is utilized to generate an the gfi ure, the red line represents the control function of the approximate sine (cosine) signal for each joint control. The lateral movement of the robot. The blue line represents the dynamics of oscillator is described by control function of the vertical movement. 𝑥 =−𝑦𝜀 6. Performance Testing and Analysis (4) 󸀠 3 𝑦 = (𝑘𝑥+𝑎 𝑦−𝑎 𝑦 ) 6.1. Simulation Test Analysis. ADAMS is used as the emu- 1 2 lation platform, and the serpentine gait mode of the snake- where x and y are the output of oscillator that will be like robot is emulated and analyzed. We discuss parameter B used as the desired oscillatory signal of each joint, where𝜀 , (amplitude of the joint angle) and how it aec ff ts the stability y Journal of Robotics 7 2 x(t) y(t) 1.5 0.5 rad 0 −0.5 −1 −1.5 −2 0 5 10 15 20 25 30 35 40 45 50 t (s) Figure 13: CPG output signal. Figure 14: Exercise states at different B values. model_3 model_3 B=PI/2 B=PI/3 PART26: PART/26 PART26: PART/26 1500.0 2500.0 2000.0 1000.0 1500.0 500.0 1000.0 500.0 0.0 0.0 −500.0 −500.0 −1000.0 −1000.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 Analysis: Last_Run Time (sec) 2016-12-14 11:32:55 Analysis: Last_Run Time (sec) 2016-12-14 12:03:42 model_3 model_3 B=PI/4 B=PI/6 PART26: PART/26 PART26: PART/26 2000.0 4500.0 1500.0 3500.0 2500.0 1000.0 500.0 1500.0 0.0 500.0 0.0 −500.0 −500.0 −1000.0 −1500.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 Analysis: Last_Run Time (sec) 2016-12-14 15:44:49 Analysis: Last_Run Time (sec) 2016-12-14 12:15:16 Figure 15: Displacement curve of dier ff ent B values. of peristaltic motion and the speed of motion based on It can be observed that motion displacement in X axe is (3), and other parameters and gaits simulation methods are chaotic over the change of B and it reaches a maximum if ignored. and only if𝐵=𝜋/3 ; on the contrary, Z motion displacement In the emulation process, let𝑎=𝑒 ,𝛾=0 ,𝜔=2𝜋 ,and increases over the decrease of B (Figure 15). 𝐴=𝜋/3 , and parameter B equates to𝜋/2 ,𝜋/3 ,𝜋/4 ,and For further strengthening the points above, our prototype 𝜋/6 , respectively. As shown in Figure 14, the corresponding machine is used to conduct the eld fi experiments and the motion gaits are directly emulated by different B values; (1) result indicates that our simulations can be well benchmarked as a case (𝐵=/𝜋2 or𝐵=𝜋/3 ), serpentine motion of our with the prototype robot’s eld fi s tests and further proves that acase𝐵=/𝜋3 and the serpentine motion is performed best robot is a better approximation to natural snakes’ movement; (2) when coming to the case𝐵=𝜋/4 ,the serpentine with our emulation results (Figure 16). motion uniformity in all joints is no longer kept; (3) for the case (𝐵=𝜋/6 ), the robot motion can be shaped in 6.2. System Test Analysis. The terminal App is able to monitor U. the snake-like robot motion by the automatic and manual Length (mm) Length (mm) Length (mm) Length (mm) 8 Journal of Robotics Figure 16: Different number of S-shape curve. Console Video sources Connect Wifi status:normal Bluetooth status:disconnected Connect Gait control: Lateral Serpentine Creeping drift Tumbling Climbing Data port selection : port1 Figure 17: Video/gaits display interface. Gait adjustment: F F F Thermal imaging sensor LSS R S R B B Serpentine Creeping Lateral drift Sensor data: CO concentration : 0ppm Laser ranging value: 1.36m Temperature and humidity value: 15 ＃ 60% Air pressure value: 960mbar Figure 18: Sensors information display interface. operation and, meanwhile through WiFi and Bluetooth, it 7. Conclusion acquires image information and multisensors’ data (Figures 17 and 18). The experimental results show that the perfor- This paper presents a design method of a snake-like robot that adapts to complex environment. By properly designing the mance of our proposed prototype machine can meet the communication requirements in a complex environment. control system, mechanical structure, and motion control, we Journal of Robotics 9 are able to emulate and test the snake-like robot. Our snake- [9] L.Douadi,D.Spinello,W. Gueaieb,and H.Sarfraz, “Planar kinematics analysis of a snake-like robot,” Robotica,vol. 32, no. like robot can achieve multistep motion control and it can 5, pp. 659–675, 2014. gather multisensors’ information in complex environment. [10] L. Pfotzer, S. Klemm, A. Roennau, J. M. Zollner ¨ , and R. Dill- It also has capacity in expansion, real-time performance, mann, “Autonomous navigation for reconfigurable snake-like and stability. The proposed design of snake-like robot is a robots in challenging, unknown environments,” Robotics and pavement to research and development of future counterparts Autonomous Systems,vol.89, pp.123–135, 2017. that will be applied in seismic search and rescue, pipeline [11] H. Komura, H. Yamada, and S. Hirose, “Development of snake- inspection, space exploration, and many other fields. It can like robot ACM-R8 with large and mono-tread wheel,” Ad- provide reference values for other bionic robots research. vanced Robotics,vol.29,no. 17,pp. 1081–1094,2015. [12] E.Ayvali,R.A.Srivatsan, L. Wang,R. Roy,N.Simaan,and Data Availability H. Choset, “Using Bayesian optimization to guide probing of a flexible environment for simultaneous registration and The data used to support the findings of this study are stiffness mapping,” in Proceedings of the 2016 IEEE International available from the corresponding author upon request. Conference on Robotics and Automation, ICRA 2016,pp. 931– 936, Sweden, May 2016. [13] K. Watanabe, M. Iwase, S. Hatakeyama, and T. Maruyama, Conflicts of Interest “Control strategy for a snake-like robot based on constraint force and verification by experiment,” Advanced Robotics,vol. The authors declare that they have no conflicts of interest. 23, no. 7-8,pp.907–937,2009. [14] T. Song, Y.lu, and Z.li, “Structural designand research of the Acknowledgments bionic snake-like robot,” Advanced Materials Research,vol. 538- 541, pp. 3034–3037, 2012. The paper is supported by the Science and Technology Sup- [15] C. Behn, L. Heinz, and M. Krug ¨ er, “Kinematic and dynamic port Program of Sichuan Province (No. 2015JTD0020) and description of non-standard snake-like locomotion systems,” the Science and Technology Support Program of Chengdu Mechatronics, vol. 37, pp. 1–11, 2016. City (No. 2015-HM01-00360-SF). [16] Z. Lu and B. Li, “Dynamics simulation analysis on serpentine swimming performance of a snake-like robot,” Jiqiren/Robot, vol.37,no. 6,pp. 748–753,2015. References [17] X.Wang,H.Jin, Y. Zhu et al.,“Serpenoid polygonal rolling [1] X.Dong, M.Raffles, S.C. Guzman, D.Axinte, and J.Kell, for chain-type modular robots: A study of modeling, pattern “Design and analysis of a family of snake arm robots connected switching and application,” Robotics and Computer-Integrated by compliant joints,” Mechanism and Machine eTh ory ,vol.77, Manufacturing, vol. 39, pp. 56–67, 2016. pp. 73–91, 2014. [18] T. Ohashi, H. Yamada, and S. Hirose, “Loop forming snake-like [2] K.Yang, T. Ge, and X.Wang,“Stability analysis ofswimming robot ACM-R7 and its serpenoid oval control,” in Proceedings of configuration of a underwater self-reconfigurable robot,” the 23rd IEEE/RSJ 2010 International Conference on Intelligent Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering Robots and Systems, IROS 2010, pp. 413–418, Taiwan, October University, vol.37,no.7,pp.891–895, 2016. [3] G. Niu, L. Wang, and G. Zong, “Attitude control based on fuzzy [19] Y. Umetani and S. Hirose, “Biomechanical Study of Serpentine logic for continuum aircraft fuel tank inspection robot,” Journal Locomotion,” in On eTh ory and Practice of Robots and Manip- of Intelligent & Fuzzy Systems: Applications in Engineering and ulators,vol.201 of CISM International Centre for Mechanical Technology, vol.29,no.6,pp.2495–2503, 2015. Sciences, pp. 171–184, Springer Vienna, Vienna, 1974. [4] M.S. Moses,R. J. Murphy, M.D.M.Kutzer,and M.Armand, [20] G. Yang, S. Ma, B. Li, and M. Wang, “An HCCPG model-based “Modeling Cable and Guide Channel Interaction in a High- 3D gait control of a snake-like robot,” Jiqiren/Robot,vol.36, no. Strength Cable-Driven Continuum Manipulator,” IEEE/ASME 6, pp. 697–703, 2014. Transactions on Mechatronics,vol. 20, no.6, pp. 2876–2889, [21] X. Wu and S. Ma, “CPG-based control of serpentine locomotion of a snake-like robot,” Mechatronics,vol.20, no.2,pp.326–334, [5] N.M.Nor and S.Ma, “Smoothtransition for CPG-based body 2010. shape control of a snake-like robot,” Bioinspiration & Biomimet- [22] Z.Wang,Q.Gao,and H. Zhao, “CPG-Inspired Locomotion ics,vol.9, no. 1,2014. Control for a Snake Robot Basing on Nonlinear Oscillators,” Journal of Intelligent & Robotic Systems,vol.85,no.2,pp.209– [6] K. Ito and H. Maruyama, “Semi-autonomous serially connected 227, 2017. multi-crawler robot for search and rescue,” Advanced Robotics, vol. 30, no. 7, pp.489–503,2016. [23] N. M. Nor and S. Ma, “A simplified CPGs network with phase oscillator model for locomotion control of a snake-like robot,” [7] X. Zang, Y. Liu, Z. Lin, C. Zhang, and S. Iqbal, “Two multi- Journal of Intelligent & Robotic Systems, vol.75,no.1, pp. 71–86, linked rescue robots: Design, construction and field tests,” Journal of Advanced Mechanical Design, Systems, and Manufac- turing, vol.10,no. 6,2016. [8] B. Ibrahimov, “Development of a Decision Making Guide for Locomotion Design for In-pipe Inspection Robots - One Step towards Open Innovation in Robotics,” IFAC-PapersOnLine, vol. 49, no. 29, pp. 77–82, 2016. International Journal of Advances in Rotating Machinery Multimedia Journal of The Scientific Journal of Engineering World Journal Sensors Hindawi Hindawi Publishing Corporation Hindawi Hindawi Hindawi Hindawi www.hindawi.com Volume 2018 http://www www.hindawi.com .hindawi.com V Volume 2018 olume 2013 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 Journal of Control Science and Engineering Advances in Civil Engineering Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 Submit your manuscripts at www.hindawi.com Journal of Journal of Electrical and Computer Robotics Engineering Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 VLSI Design Advances in OptoElectronics International Journal of Modelling & Aerospace International Journal of Simulation Navigation and in Engineering Engineering Observation Hindawi Hindawi Hindawi Hindawi Volume 2018 Volume 2018 Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com www.hindawi.com www.hindawi.com Volume 2018 International Journal of Active and Passive International Journal of Antennas and Advances in Chemical Engineering Propagation Electronic Components Shock and Vibration Acoustics and Vibration Hindawi Hindawi Hindawi Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Robotics Hindawi Publishing Corporation

Design and Realize a Snake-Like Robot in Complex Environment

Download PDF
10 pages

Loading next page...
 
/lp/hindawi-publishing-corporation/design-and-realize-a-snake-like-robot-in-complex-environment-UmRVPG2MIB

References (27)

Publisher
Hindawi Publishing Corporation
Copyright
Copyright © 2019 Bingqi Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ISSN
1687-9600
eISSN
1687-9619
DOI
10.1155/2019/1523493
Publisher site
See Article on Publisher Site

Abstract

Hindawi Journal of Robotics Volume 2019, Article ID 1523493, 9 pages https://doi.org/10.1155/2019/1523493 Research Article 1 1 1 1 1 Bingqi Liu, Mingzhe Liu , Xianghe Liu, Xianguo Tuo, Xing Wang, 1 2 Shibo Zhao, and Tingting Xiao State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, China Deyang Science and Technology Information Research Institute, Deyang, China Correspondence should be addressed to Mingzhe Liu; liumz@cdut.edu.cn Received 23 October 2018; Accepted 14 November 2018; Published 3 February 2019 Academic Editor: Gordon R. Pennock Copyright © 2019 Bingqi Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Aiming at high performance requirements of snake-like robots under complex environment, we present a control system of our proposed design which utilizes a STM32 as the core processor and incorporates real-time image acquisition, multisensor fusion, and wireless communication technology. We use Solidworks to optimize the design of head, body, and tail joint structure of the snake-like robot. The system is a real-time system with a simple-circuit structure and multidegrees of freedom are attributed to the flawless design of control system and mechanical structure. We propose a control method based on our simplified CPG model. Meanwhile, we improve Serpenoid control function and then investigate how dieff rent parameters aec ff t the motion gait in terms of ADAMS emulation. Finally, experimental results show that the snake-like robot can tackle challenging problems including multi- information acquisition and processing, multigait stability, and autonomous motion and further verify the reliability and accuracy of the system in our combinatory experiments. 1. Introduction Several disadvantages still exist in many cases and pro- totypes including shortcomings of mechanical structures, With the rapid development of science and technology, bionic unreliable control strategy, and algorithms [13, 14]. Therefore, robots, especially snake-like robots, have been widely used in a snake-like robot which adapts to changes in complex military, civil and space, and other eld fi s [1–5]. Robots can environment is proposed to overcome current problems in demonstrate advantages in camouafl ge and multiple degrees the snake-like robot design. In this paper, the prototype of of freedom, with which dangerous works can be completed the snake-like robot is designed in a routine of mechanical in a total and/or partial replace of people’s roles, such as design, motion control, signal acquisition, data transmission, investigation, search and rescue, patrol, pipeline inspection, simulation research, and prototype test, which owes small and space exploration. To strengthen advantages and usages volume, light weight, and multiple degrees of freedom. The of snake-like robots, many scholars have conducted active emulation experiment and prototype test adequately proved studies on the snake-like robots [6–10]. Leading Research that the stability of the snake-like robot is expected. Groups include the group led by Professor Hirsoe in Tokyo Institute of Technology (ACM R8), the robot team in 2. Overall Scheme Design Carnegie Mellon University (Uncle Sam), and the robot team in Michigan University (OmniTread). ACM R7 may bend its The snake-like robot studied in this paper mainly includes body gfi ure into a circle and rolls forward in a grass land like the mechanical structure, the control system, and the power a wheel [11]; Uncle Sam is categorized into a reconfigurable supply system (Figure 1). The mechanical structure consists genre of robots, which is extremely suitable in applications in of three modules: head, body, and tail. The control system ducts, slits, etc. [12]; OmniTread is skilled at climbing upward is composed of 3 main parts: a master control system, slave and able to crawl across pipeline with a diameter of 11 cm to control systems, and a monitoring system. The master system 24cm. is integrated in the snake head, which mainly undertakes 2 Journal of Robotics Snake-like robot Mechanical structure Control system Power supply system Snake head Snake body Snake tail Master control Slave control Monitoring Battery Voltage- module module module system system system module stabilized module Figure 1: Design diagram of the overall scheme. Figure 2: Assembly diagram of the snake-like robot. Figure 3: Design diagram of the snake body joint. the role of automatic detection of the external environment, lead to a more compact structure and high spatial degrees of and controls the slave control system by sending commands. freedom (Figure 2). Solidworks is employed to optimize the The slave control systems are distributed in body and tail, design of head, body, and tail joint structure of the snake-like completing the specific gait regulation and control. The robot. monitoring system is hosted in a phone APP, which realizes the monitor and display function of sampled information. 3.1. Snake Body Joints Design. Joint modules are modelled to The power supply system consists of a rechargeable lithium satisfy spatial requirements for lithium battery modules, the battery module and a voltage-stabilized module that meets slave control circuit boards, and the motors. The draw of the energy requirements for the entire snake-like robot. Each snake body joint is viewed by a planar figure as shown in joint incorporates such a power module in the snake-like Figure 3, where (A) is the link between the joints, to ensure robot. that the joints are to complete the angle of±135 degrees of rotation; (B1) and (B2) are horizontal and vertical motors; the two motors are integrated into a joint to narrow the snake 3. Mechanical Structure Design space to ensure the flexibility of the joints; (C) and (E) are the Traditional orthogonal structure requires orthogonal place- lithium battery and the fixed position for slave control circuit ment of joints, and each joint only has one motor [14]. board, respectively; (D) and (F) are the xfi ing holes for the This paper uses the method that requires two motors in longitudinal and transverse motors; (G) is the support for the orthogonal placement for each joint. This improvement will metal sheet of the snake body joint. Journal of Robotics 3 Figure 4: Design diagram of the snake head joint. Figure 5: Design diagram of the snake tail joint. 3.2. Snake Head Joint Design. The snake head joint is the 4. Control System Design core component of the entire snake-like robot. The draw The master control system is made up of a camera module, of the snake head joint is viewed by a planar figure as a laser ranging module, a temperature-humidity sensor, an shown in Figure 4. A motor (K) is placed in the longitudinal air pressure sensor, a thermal imaging sensor, and a CO position of head joint under the premise of horizontal sensor. Among them, the camera module and the thermal movement in snake head joint. The front of the snake head imaging sensor collect environment information and human joint is streamlined to reduce the resistance of the forward perception information and display them by images. The movement and to position the camera (H). At the same time, slave control systems coordinate with the master control the snake head joint is equipped with a lighting device (I) to system to control and adjust the snake-like robot’s movement work in a dark environment. The battery (J) is installed for gaits with the ZigBee wireless transmission mode. The slave the snake head portion. control systems generate PWM signals to drive correspond- ing motors. The monitoring system is equipped with WiFi 3.3. Snake Tail Joint Design. The draw of the snake tail and Bluetooth modules as communication channels with the joint is viewed by a planar figure as Figure 5. Taking their master system, which holds control and monitor tasks in the corresponding structures into account including the laser snake-like robot (Figure 6). distance measuring sensor (L), infrared heat source sensor (M), and the master control board (O), the temperature- humidity sensor and air pressure sensor are embedded on the 4.1. Master Control System Design. The master control system master control circuit board; additionally a small portion of consists of four main modules: a core processor, a wireless space is reserved for a CO (N) sensor. For the position case communication module, a camera module, and multisensors of the tail motor, its structure is right inversed to that of the (Figure 7). The master control system receives the control head motor. commands from the monitoring system and obtains data 4 Journal of Robotics Terminal WiFi video reception App Bluetooth module Monitoring system WiFi video launch Bluetooth module Zigbee Master control system of snake-like robot Laser Temperature Air Thermal Camera CO ranging and humidity pressure imaging module sensor module sensor sensor sensor Master control system Zigbee Zigbee Zigbee Execution Execution Execution unit unit unit PWM servo PWM servo PWM servo control control control Slave control system Figure 6: Design diagram of the control system. Figure 7: Circuit diagram of the master control system. from multiple sensors through the Bluetooth module. The coordinator. Meanwhile, the master control system sends monitoring system determines the motion gait of the snake- demands to the core processor in the serial interface mode. like robot according to control demands and displays the These demands drive motors to complete the corresponding sensor parameters on the APP. The master control system gait operation. In order to facilitate the movement of snake- uses the WiFi module to communicate with the monitoring like robots and meet the power supply needs, we select the system and obtain the image information of a RGB camera 7.4V lithium battery-powered solution, through RT9193 to in real time. The system is equipped with LED lights for convert from 7.4V to 3.3V for the control circuit board; at the camera so as to obtain the high-definition image in the the same time, a diode will enable 7.4V to lower down 6V, dark environment. The CC2530 coordinator communicates to ensure reliable operation of motors (Figure 8). with the Zigbee, via the CC2541 Bluetooth module to transfer multisensor data. 4.3. Monitoring System Design. The monitoring system is developed by Java based on the Android system. The control 4.2. Slave Control System Design. The slave control system interface of the host computer is divided into two interfaces: selects STM8s003f3p6 as the core processor. The snake-like the camera real-time acquisition in the first interface; thermal robot uses 6V-powered high-torque motors supplied by the imaging, gait control, and sensor detection in the second battery with 6V, 250mAh lithium battery, to ensure that the interface. The gait control consists of vfi e gaits: serpentine snake-like robot running lasts more than one hour. The mas- locomotion, creeping, lateral displacement, tumbling, and ter control system sends wireless instructions to the CC2530 terminal node in the slave system through the CC2530 climbing (Figure 9). Journal of Robotics 5 Figure 8: Circuit diagram of the slave control system. Snake-like robot Video sources Gaits control Sensor detection Air Temperature Laser Thermal CO Camera pressure and humidity ranging imaging sensor module sensor sensor module sensor WiFi Bluetooth Bluetooth transmission transmission transmission Real-time detection and display Serpentine Lateral Creeping Tumbling Climbing Locomotion displacement Bluetooth transmission debugging and control Figure 9: Logic diagram of the monitoring system. 5. Motion Control Design Equation (2) is obtained by simplifying (1): 𝜙 =𝐴 sin(𝜔𝑡+𝐵𝑖 )+𝛾 (2) There are three controls modes for snake-like robot: gaits control (GC) based mode [15], Serpenoid control function where𝜙 is the angle between joint 𝑖 and(𝑖−1) (𝑖= (SCF) based mode [16–19], and central pattern generator 1,2...𝑛 ),𝐴 is the amplitude of the joint angle when𝛾=0 , (CPG) based mode [20–23]. SCF and CPG are key focuses 𝜔 is the joint radial frequency,𝐵 is the initial phase of the in this paper. function,𝛾 is the deflection angle of the entire system, and (𝜔𝑡+𝐵𝑖) is the phase. 5.1. Serpenoid Control Function. Hirose proposed the Ser- According to (2), the condition𝑡= 0 and𝜙 =0̸ is penoid control function via (1) which imitates the movement not consistent with the actual requirements. Therefore, (2) is of nature snake from a long-term observation of snake transformed to guarantee𝜙 =0 and𝑡=0 as (3). behaviors [17]. −𝑡 𝜙 =(1−𝑎 )𝐴 sin(𝜔𝑡+𝐵𝑖 )+𝛾 𝑎≥1 (3) 𝑥 (𝑠)=∫ cos(𝑎 cos(𝑏𝜎+𝑐𝜎 )) As demonstrated in Figure 10, the transformation does not alter both minimum and maximum values over a long (1) time, except state differences in initial stage. This transforma- 𝑦 (𝑠)=∫ sin(𝑎 cos(𝑏𝜎+𝑐𝜎 )) tion does not affect the movement of the robot. 𝑑𝜎 𝑑𝜎 6 Journal of Robotics 1.5 The image of Eq.(2) The image of Eq.(3) Initial poin1 Initial point2 0.5 rad 0 −0.5 −1 −1.5 0 1 2 3 4 5 6 7 8 9 10 t (s) Figure 10: Contrast diagrams of the equations. CPG1 CPG2 CPGn-1 CPGn Xn-1 Yn-1 X1 Y1 X2 Y2 Xn Yn Figure 11: Convergence graph of CPG. 2.5 1.5 0.5 −0.5 −1 −1.5 −2 −2.5 −4 −3 −2 −1 0 1 2 3 4 Figure 12: Convergence graph of CPG. 5.2. CPG Control Mode. A chain network is included by 2n 𝑘 ,𝑎 ,and𝑎 are constants. CPG can converge if parameters 1 2 oscillator (Figure 11); the output of the distributed oscillator are properly choseninmodel (Figure 12). can provide movement control signals for the snake-like From Figure 13, it can be seen that the model exhibits dual robot. stable sine or cosine dynamics over time about x and y. In A single simplified CPG model is utilized to generate an the gfi ure, the red line represents the control function of the approximate sine (cosine) signal for each joint control. The lateral movement of the robot. The blue line represents the dynamics of oscillator is described by control function of the vertical movement. 𝑥 =−𝑦𝜀 6. Performance Testing and Analysis (4) 󸀠 3 𝑦 = (𝑘𝑥+𝑎 𝑦−𝑎 𝑦 ) 6.1. Simulation Test Analysis. ADAMS is used as the emu- 1 2 lation platform, and the serpentine gait mode of the snake- where x and y are the output of oscillator that will be like robot is emulated and analyzed. We discuss parameter B used as the desired oscillatory signal of each joint, where𝜀 , (amplitude of the joint angle) and how it aec ff ts the stability y Journal of Robotics 7 2 x(t) y(t) 1.5 0.5 rad 0 −0.5 −1 −1.5 −2 0 5 10 15 20 25 30 35 40 45 50 t (s) Figure 13: CPG output signal. Figure 14: Exercise states at different B values. model_3 model_3 B=PI/2 B=PI/3 PART26: PART/26 PART26: PART/26 1500.0 2500.0 2000.0 1000.0 1500.0 500.0 1000.0 500.0 0.0 0.0 −500.0 −500.0 −1000.0 −1000.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 Analysis: Last_Run Time (sec) 2016-12-14 11:32:55 Analysis: Last_Run Time (sec) 2016-12-14 12:03:42 model_3 model_3 B=PI/4 B=PI/6 PART26: PART/26 PART26: PART/26 2000.0 4500.0 1500.0 3500.0 2500.0 1000.0 500.0 1500.0 0.0 500.0 0.0 −500.0 −500.0 −1000.0 −1500.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 Analysis: Last_Run Time (sec) 2016-12-14 15:44:49 Analysis: Last_Run Time (sec) 2016-12-14 12:15:16 Figure 15: Displacement curve of dier ff ent B values. of peristaltic motion and the speed of motion based on It can be observed that motion displacement in X axe is (3), and other parameters and gaits simulation methods are chaotic over the change of B and it reaches a maximum if ignored. and only if𝐵=𝜋/3 ; on the contrary, Z motion displacement In the emulation process, let𝑎=𝑒 ,𝛾=0 ,𝜔=2𝜋 ,and increases over the decrease of B (Figure 15). 𝐴=𝜋/3 , and parameter B equates to𝜋/2 ,𝜋/3 ,𝜋/4 ,and For further strengthening the points above, our prototype 𝜋/6 , respectively. As shown in Figure 14, the corresponding machine is used to conduct the eld fi experiments and the motion gaits are directly emulated by different B values; (1) result indicates that our simulations can be well benchmarked as a case (𝐵=/𝜋2 or𝐵=𝜋/3 ), serpentine motion of our with the prototype robot’s eld fi s tests and further proves that acase𝐵=/𝜋3 and the serpentine motion is performed best robot is a better approximation to natural snakes’ movement; (2) when coming to the case𝐵=𝜋/4 ,the serpentine with our emulation results (Figure 16). motion uniformity in all joints is no longer kept; (3) for the case (𝐵=𝜋/6 ), the robot motion can be shaped in 6.2. System Test Analysis. The terminal App is able to monitor U. the snake-like robot motion by the automatic and manual Length (mm) Length (mm) Length (mm) Length (mm) 8 Journal of Robotics Figure 16: Different number of S-shape curve. Console Video sources Connect Wifi status:normal Bluetooth status:disconnected Connect Gait control: Lateral Serpentine Creeping drift Tumbling Climbing Data port selection : port1 Figure 17: Video/gaits display interface. Gait adjustment: F F F Thermal imaging sensor LSS R S R B B Serpentine Creeping Lateral drift Sensor data: CO concentration : 0ppm Laser ranging value: 1.36m Temperature and humidity value: 15 ＃ 60% Air pressure value: 960mbar Figure 18: Sensors information display interface. operation and, meanwhile through WiFi and Bluetooth, it 7. Conclusion acquires image information and multisensors’ data (Figures 17 and 18). The experimental results show that the perfor- This paper presents a design method of a snake-like robot that adapts to complex environment. By properly designing the mance of our proposed prototype machine can meet the communication requirements in a complex environment. control system, mechanical structure, and motion control, we Journal of Robotics 9 are able to emulate and test the snake-like robot. Our snake- [9] L.Douadi,D.Spinello,W. Gueaieb,and H.Sarfraz, “Planar kinematics analysis of a snake-like robot,” Robotica,vol. 32, no. like robot can achieve multistep motion control and it can 5, pp. 659–675, 2014. gather multisensors’ information in complex environment. [10] L. Pfotzer, S. Klemm, A. Roennau, J. M. Zollner ¨ , and R. Dill- It also has capacity in expansion, real-time performance, mann, “Autonomous navigation for reconfigurable snake-like and stability. The proposed design of snake-like robot is a robots in challenging, unknown environments,” Robotics and pavement to research and development of future counterparts Autonomous Systems,vol.89, pp.123–135, 2017. that will be applied in seismic search and rescue, pipeline [11] H. Komura, H. Yamada, and S. Hirose, “Development of snake- inspection, space exploration, and many other fields. It can like robot ACM-R8 with large and mono-tread wheel,” Ad- provide reference values for other bionic robots research. vanced Robotics,vol.29,no. 17,pp. 1081–1094,2015. [12] E.Ayvali,R.A.Srivatsan, L. Wang,R. Roy,N.Simaan,and Data Availability H. Choset, “Using Bayesian optimization to guide probing of a flexible environment for simultaneous registration and The data used to support the findings of this study are stiffness mapping,” in Proceedings of the 2016 IEEE International available from the corresponding author upon request. Conference on Robotics and Automation, ICRA 2016,pp. 931– 936, Sweden, May 2016. [13] K. Watanabe, M. Iwase, S. Hatakeyama, and T. Maruyama, Conflicts of Interest “Control strategy for a snake-like robot based on constraint force and verification by experiment,” Advanced Robotics,vol. The authors declare that they have no conflicts of interest. 23, no. 7-8,pp.907–937,2009. [14] T. Song, Y.lu, and Z.li, “Structural designand research of the Acknowledgments bionic snake-like robot,” Advanced Materials Research,vol. 538- 541, pp. 3034–3037, 2012. The paper is supported by the Science and Technology Sup- [15] C. Behn, L. Heinz, and M. Krug ¨ er, “Kinematic and dynamic port Program of Sichuan Province (No. 2015JTD0020) and description of non-standard snake-like locomotion systems,” the Science and Technology Support Program of Chengdu Mechatronics, vol. 37, pp. 1–11, 2016. City (No. 2015-HM01-00360-SF). [16] Z. Lu and B. Li, “Dynamics simulation analysis on serpentine swimming performance of a snake-like robot,” Jiqiren/Robot, vol.37,no. 6,pp. 748–753,2015. References [17] X.Wang,H.Jin, Y. Zhu et al.,“Serpenoid polygonal rolling [1] X.Dong, M.Raffles, S.C. Guzman, D.Axinte, and J.Kell, for chain-type modular robots: A study of modeling, pattern “Design and analysis of a family of snake arm robots connected switching and application,” Robotics and Computer-Integrated by compliant joints,” Mechanism and Machine eTh ory ,vol.77, Manufacturing, vol. 39, pp. 56–67, 2016. pp. 73–91, 2014. [18] T. Ohashi, H. Yamada, and S. Hirose, “Loop forming snake-like [2] K.Yang, T. Ge, and X.Wang,“Stability analysis ofswimming robot ACM-R7 and its serpenoid oval control,” in Proceedings of configuration of a underwater self-reconfigurable robot,” the 23rd IEEE/RSJ 2010 International Conference on Intelligent Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering Robots and Systems, IROS 2010, pp. 413–418, Taiwan, October University, vol.37,no.7,pp.891–895, 2016. [3] G. Niu, L. Wang, and G. Zong, “Attitude control based on fuzzy [19] Y. Umetani and S. Hirose, “Biomechanical Study of Serpentine logic for continuum aircraft fuel tank inspection robot,” Journal Locomotion,” in On eTh ory and Practice of Robots and Manip- of Intelligent & Fuzzy Systems: Applications in Engineering and ulators,vol.201 of CISM International Centre for Mechanical Technology, vol.29,no.6,pp.2495–2503, 2015. Sciences, pp. 171–184, Springer Vienna, Vienna, 1974. [4] M.S. Moses,R. J. Murphy, M.D.M.Kutzer,and M.Armand, [20] G. Yang, S. Ma, B. Li, and M. Wang, “An HCCPG model-based “Modeling Cable and Guide Channel Interaction in a High- 3D gait control of a snake-like robot,” Jiqiren/Robot,vol.36, no. Strength Cable-Driven Continuum Manipulator,” IEEE/ASME 6, pp. 697–703, 2014. Transactions on Mechatronics,vol. 20, no.6, pp. 2876–2889, [21] X. Wu and S. Ma, “CPG-based control of serpentine locomotion of a snake-like robot,” Mechatronics,vol.20, no.2,pp.326–334, [5] N.M.Nor and S.Ma, “Smoothtransition for CPG-based body 2010. shape control of a snake-like robot,” Bioinspiration & Biomimet- [22] Z.Wang,Q.Gao,and H. Zhao, “CPG-Inspired Locomotion ics,vol.9, no. 1,2014. Control for a Snake Robot Basing on Nonlinear Oscillators,” Journal of Intelligent & Robotic Systems,vol.85,no.2,pp.209– [6] K. Ito and H. Maruyama, “Semi-autonomous serially connected 227, 2017. multi-crawler robot for search and rescue,” Advanced Robotics, vol. 30, no. 7, pp.489–503,2016. [23] N. M. Nor and S. Ma, “A simplified CPGs network with phase oscillator model for locomotion control of a snake-like robot,” [7] X. Zang, Y. Liu, Z. Lin, C. Zhang, and S. Iqbal, “Two multi- Journal of Intelligent & Robotic Systems, vol.75,no.1, pp. 71–86, linked rescue robots: Design, construction and field tests,” Journal of Advanced Mechanical Design, Systems, and Manufac- turing, vol.10,no. 6,2016. [8] B. Ibrahimov, “Development of a Decision Making Guide for Locomotion Design for In-pipe Inspection Robots - One Step towards Open Innovation in Robotics,” IFAC-PapersOnLine, vol. 49, no. 29, pp. 77–82, 2016. International Journal of Advances in Rotating Machinery Multimedia Journal of The Scientific Journal of Engineering World Journal Sensors Hindawi Hindawi Publishing Corporation Hindawi Hindawi Hindawi Hindawi www.hindawi.com Volume 2018 http://www www.hindawi.com .hindawi.com V Volume 2018 olume 2013 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 Journal of Control Science and Engineering Advances in Civil Engineering Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 Submit your manuscripts at www.hindawi.com Journal of Journal of Electrical and Computer Robotics Engineering Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 VLSI Design Advances in OptoElectronics International Journal of Modelling & Aerospace International Journal of Simulation Navigation and in Engineering Engineering Observation Hindawi Hindawi Hindawi Hindawi Volume 2018 Volume 2018 Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com www.hindawi.com www.hindawi.com Volume 2018 International Journal of Active and Passive International Journal of Antennas and Advances in Chemical Engineering Propagation Electronic Components Shock and Vibration Acoustics and Vibration Hindawi Hindawi Hindawi Hindawi Hindawi www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018 www.hindawi.com Volume 2018

Journal

Journal of Robotics – Hindawi Publishing Corporation

Published: Feb 3, 2019

There are no references for this article.