Modeling and simulation of spider’s walking

Abstract

Currently robot designers are ever more inspired by nature to develop and design legged robots to mimic the walking style of insects over uneven and rough surfaces. In this work, walking behavior and method of a kind of spider Araneus diadematus are investigated. Image processing techniques are used to obtain kinematic parameters of the spider’s legs. The positions of defi ned points on the spider’s legs were recorded in terms of time. After extracting the necessary data, a linkage mechanism of the legs was designed. By using the position of defi ned points on spider’s legs as input to our model and implementation of trigonometric relations, parameters such as angle, angular velocity, and angular acceleration of each link were obtained. Then, a model of linkage mechanism for the spider’s legs in SIMULINK environment of MATLAB was created. By allocating mechanical properties of linkages such as mass and moment of inertia to the model, quantities of torque in joints, which were needed for producing the traversed path of spider’s legs, were obtained. These quantities can be used for selection and control of actuators in the novel robotic system in order to mimic the spider’s walking style. Today there exist many challenges to fabricate robots that mimic insect’s movements. The reason behind this requirement is that wheeled robots are unable to go over different obstacles like uneven surfaces. Wheeled robots have higher effi ciency in terms of energy consumption and their control is also easy. On the other hand, legged robots due to the fact that they can move over uneven surfaces that are closer to human’s real world environment would be more effective. Based on these advantages, the tendency of engineers towards fabrication of legged robots which are inspired from insect walking has noticeably increased. In this regards, several investigations on different insects such as cockroaches [1–15], ants [16–21], and crickets [22–30] have been carried out. Mean while another insect which has shown a higher level of fland performance during walking, has been the spider which has high mobility over uneven and irregular surfaces. Note that the animals move the greatest distance while using minimum energy [31]. Therefore, it is very important to carry out an accurate study on the spider’s walking and its mobility. Also it is crucial to determine and analyze parameters involved in its movements in order to develop the model for fabrication of legged robots. In this paper, fi rst the traversed path of the spider’s legs will be investigated. Then, the position of defi ned points on the spider’s legs and parameters relating to its movement will be determined using image processing methods. By using this data as input to an equivalent linkage mechanism of spider’s legs and employing trigonometric relations, the angle between each linkage with respect to horizontal axis will be obtained. Then, by using numerical derivation, the quantities for angular velocity and angular acceleration of the linkages will be calculated. Finally, a model of the mechanism in SIMULINK environment of MATLAB will be developed. By giving obtained parameters to this model and having mechanical properties of each link such as moment of inertia and mass, the spider’s walking will be simulated and legged robot which can mimic spider’s walking style will be developed. By implementing sensors in each joint of model in SIMULINK environment, quantities of torque in the joints which are required to traverse the path of spider’s legs can be obtained.