The Development and Designing of Legged Robots - Literature review Example

BUILDING LEGGED ROBOTS Name Institution Instructor Course Date Table of Contents Introduction 2 Purpose Statement (Thesis) 4 Literature Review 4 Discussion 5 Design and Development 5 Programming 7 Conclusion 8 References 10 Introduction Legged robots are a type of robots, which are designed to move from one place to another. In fact, these robots are also termed as the mobile robots or walking robots. These legged robots are mostly using four legs and six legs, but there are developments which have resulted in the designing of a two legged robot which is more or less like a human being. The development of robots is one of the fascinating research topics in the fields of engineering. There have been developments in improving the design and architecture of robots. The legged robot or walking robot is one of the advancements in engineering of robots (Warnakulasooriya et al., 2012, p. 1017). Robots exist in different types depending on its application, morphology and locomotion. The development of legged robots has been majorly influenced by the lack of locomotion in previous robots. Most of the previously developed robots were not able to explore different terrain. The previous robots were designed using wheels hence could not navigate in some terrain limiting their movements and locomotion. This means that the legged robot was able to climb mountains and move up and down staircases. The success in biped robots is in the development of Topio and Nao which are biped Robots. These robots are able to sing, play and move from one place to another. However, one of the challenges in building robots was to ensure the balance of the robot especially for the two legged or biped robots. Engineers were faced with the difficulty of balancing the weight in the two legged robots while the robot was kicking as well as when the robot is walking or running. Moreover, there was also need to develop control systems that would allow users and engineers to control the robot in different strategies. With the advancement in electronic engineering, it is now promising that two legged robots can be easy to develop in terms of balance and weight (Mendez et al., 2008). Purpose Statement (Thesis) The development of robots has been focusing on developing robots with more than two legs in order to maintain balance of the robot during walking and locomotion. The purpose of this paper is to discuss the building of a simple two legged robot which is capable of walking and kicking as well as maintaining its balance (Mota et al., 2010, p. 1661). In discussing the biped, the paper will focus on key areas such as design and development and programming of the two legged robots. The various activities and processes involved in the design and development as well as programming will be discussed. This development is mainly triggered by the advancements in technologies especially in the electronic engineering. In designing the robot, the hurdles included will consist of a selection of the building materials, material thickness, materials need in joint selection and assembly tolerance. In the programming section, the paper will discuss the pseudo sequences involved in walking and kicking of the robot. Literature Review The developments in technology have resulted in the designing of more autonomous robots which are offering different benefits to human beings. According to Mendez et al (2008), developing a two legged robot is complex since the engineer has to consider the aspect of balance and control during locomotion. This is compared to the existing wheeled robots which were easy in maintaining balance during movement. The legged robots should undergo certain modifications in order to achieve gaits which are coordinated. Although the field in robot building has witnessed tremendous development, the limitations in balance and control systems have not been exploited fully (Roy & Pratihar, 2013, p. 401). With the current status of technology, it is required that biped robots should be able to walk in a straight line by following programmed commands. According to Roy & Pratihar (2013) the bipedal are designed in order to perform a variety tasks which require them to have balance. For example, these the Nao and Topio robots are used as a form of entertainment. In addition, the biped robots are used in walking legs technology to assist individual with a single leg (Mendez et al., 2008). Therefore, the earlier engineers concentrated on building robots that are programmed to walk forward as well as backwards. Due to this demand, the bipedal robots many of the methods and techniques used in development of robots have focused on the need to design natural movements which are continuous. In such cases, engineers are provided with a very wide range of research on ways of improving the movements in the robots (Mota et al., 2010, p. 1663). Moreover, the current literature has also focused on techniques which control the locomotion of the robots as well as integrating sensory information in the robots to make them more humanoid. According to Hurmuzlu et al (2004), bipedal robots are unstable and cannot maintain the posture of the robot while moving at a fast speed ort while kicking, hence the need to incorporate more electrical gadgets that will enhance stability of the robot. Moreover, the building or legged robots should involve the safety issues in cases where the robot is designed to enhance human interactions (Hurmuzlu et al., 2004, p. 1647). Discussion Design and Development The design and development of bipedal robots is focused on the use of servos for designing the walking movements. According to Czarnetzki et al (2009), previous walking movements were based on walker where the servos were rotating in a parallel manner. However, this meant that the walker did not have enough balance. The biped robot incorporates a number of servo motors which increase the level of freedom allowing human kike movements in the robot. However, this is costly and requires a lot of resources. The final design involved cost effective walking robot which had stability (Warnakulasooriya et al., 2012, p. 1018). This had two legs that are connected with three servos. In addition, there is an EyeBot controller at the hip which enhances freedom of movement. In this design, the robot was able to kick and walk as well as maintain its balance. This is because; the three serves in the design provided the robot with flexibility as the robot was moving. In this biped, the EyeBot was used as the brain of the robot in controlling the movements of the robot. The EyeBot was located on top of the hip of the robot which also served as the payload. In giving the robot light weight, aluminium sheets of 2 mm thickness are used (Tickoo et al., 2007, p. 48). This provided the robot with flexibility and strength required. In enhancing stability of the robot, Solid Edge was used in enhancing successful motion control. This is useful in distributing the weight of the robot with the body mass, the height and distance between the robot’s legs (Czarnetzki et al., 2009, p. 840). Additionally, the angular motion is a factor to be considered in attaining balance and stability and counter balancing during kicking. This was attained by placing the servos in the hips and knees in a similar configuration as in human beings. Therefore, each servo was calibrated in order to accommodate angular movements in the robot. The joints were rotated by interfacing the EyeBot with the servo motors. However, this posed a problem since the motors were drawing a high amount of energy from the EyeBot since there were six servo motors. In solving this problem, the EyeBot was programmed in such a way that it controls the powering of the servos. In addition, a power circuit in the EyeBot 5 was used to control the motion of the robot (Warnakulasooriya et al., 2012, p. 1019). Figure 1. Illustration of a biped (Warnakulasooriya et al., 2012). Programming The challenge in building a biped robot was to programme the robot for movement and kicking. In this case, there are various pseudo code which were use including the following (Warnakulasooriya et al., 2012, p. 1020). Moving the robot to staring position Wait for go button to be pressed Read values for the servo to move to the next position and read speed value Move from current servo value to new servo values Repeat step 4 in all servos Once stopped, release servo handles In terms of programming the robot, the EyeBot was programmed in order to control the motion and kicking in the robot. In addition, the EyeBot was programmed in making sure that the powering of the six servos in the robot is controlled by the EyeBot in order to minimize current consumption in the robot. The initial servo rotation serves as the initializer for the robot to move. The walking and kicking movements of the biped robot is triggered by pressing the button which initializes the walking cycle of the robot. To achieve this, the biped robot was programmed with a wait key. The robot is programmed in such a way that, as soon as the robot is triggered to walk by pressing the GO button, the robots program is able to read in all the six angles of the servo. Additionally, the servo is programmed in a way that it’s able to detect the maximum speed for movement. Mendez et al (2008) argues that the in moving 60 degrees the servo takes around 2.0 seconds. This means that the values of the time taken to obtain the maximum magnitude of the servo can be calculated from the previous magnitude value (Mendez et al 2008). Moreover, the functional routine of the angular input takes a desire motion of the servo. In obtaining the total time required for movement, it is necessary to determine the difference between the time taken for the servos and desire time and add it to the movements. This is referred as the wait time which in most cases is not added to the middle of the movement. The wait time is added as a segment such that the robot starts to move at a slow speed before gaining momentum and move a maximum speed. In finishing its time segments, the robot slows down again depending on the calculated magnitudes. Therefore, a parabolic time movement is used which is more or less similar to the leg movements (Warnakulasooriya et al., 2012, p. 1021). Conclusion The development and designing of robots are one of the fascinating research topics in the fields of engineering. There have been developments in improving the design and architecture of robots. The legged robot or walking robot is one of the advancements in engineering of robots. Robots exists ion different types depending on its application, morphology and locomotion. The biggest challenge in developing biped robots is creating the balance of the robot while walking and kicking. This paper has explained the developmental design of a bipedal articulating walking robot. In this robot, balance is maintained while the robot performs it kicking and walking functions. Development of bipedal robots is focused on the use of servos for designing the walking movements. The main programming point was the EyeBot which served as the brain of the robot. It was also used in controlling the energy consumption of the robot. In developing and signing the robot, practical problems were identifies in order to achieve the balance of the biped robot. References Czarnetzki, S., Kerner, S., & Urbann, O., 2009. Observer-based dynamic walking control for biped robots. Robotics and Autonomous Systems, 57, pp. 839-845 Hurmuzlu, Y., Gnot, F., & Brogliato, B., 2004. Modelling, stability and control of biped robots – A general framework. Automatica, vol. 40, no. 10, pp. 1647-1664. Mendez, F., Alfonso, A., Schaefer, T., Crawford, D., & Tosunoglu, S., 2008. Inverse Stability Analysis of Biped Robot, Proceedings of ECTC, ASME Early Career Technical Conference. Mota, Y., Filho, A, Pina, A., 2010. Research on Bipedal Robots Applied to Society. Proceedings of the 9th Brazilian Conference on Dynamics Control and their Applications, pp. 1660-1665. Roy, S., & Pratihar, D., 2013. Dynamic modeling, stability and energy consumption analysis of a realistic six-legged walking robot. Robotics and Computer-Integrated Manufacturing, vol. 29, pp. 400–416. Tickoo, S., Maini, D., & Raina, V., 2007. CATIA V5R16 for engineers and designers. New Delhi: Dreamtech Press Warnakulasooriya, S., Bagher, A., Sherburn, N., & Shanmugavel, M., 2012. Bipedal Walking Robot-ADevelopmental Design. Procedia Engineering, vol. 41, pp. 1016 – 1021. Read More