<4D6963726F736F667420576F7264202D20C7CEE1C7D520E6C7EDC7E320E6E4E6D1203135342D313434> 1 Al-Khwarizmi Engineering Journal Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, March, (2018) P.P. 145- 155 Design of Hybrid Neural Fuzzy Controller for Human Robotic Leg System Ekhlas H. Karam* Ayam M. Abbass** Noor S. Abdul-Jaleel*** *, **Department of Computer Engineering/ University of Al-Mustansyria ***Department of Electrical Engineering/ University of Al-Mustansyria *Email: ekhlashameed@yahoo.co.uk **Email: ayammohsen@yahoo.com ***Email: mail_ns1@yhoo.com (Received 10 January 2017; accepted 7 August 2017) https://doi.org/10.22153/kej.2018.08.007 Abstract In this paper, the human robotic leg which can be represented mathematically by single input-single output (SISO) nonlinear differential model with one degree of freedom, is analyzed and then a simple hybrid neural fuzzy controller is designed to improve the performance of this human robotic leg model. This controller consists from SISO fuzzy proportional derivative (FPD) controller with nine rules summing with single node neural integral derivative (NID) controller with nonlinear function. The Matlab simulation results for nonlinear robotic leg model with the suggested controller showed that the efficiency of this controller when compared with the results of the leg model that is controlled by PI+2D, PD+NID, and FPD-ID controllers. Keywords: Fuzzy proportional derivative controller, Matlab simulation results, Nonlinear differential leg model, PID controller, single node neural controller. 1. Introduction The classical robots are commonly used for industrial automation and use in applications that are remote from human life and activities. However, recently the usage of robots has been changed from industrial applications to helpful for human robot system. With increasing aging societies, robots that used to support human in his activities in daily environments such as in offices, homes, school and hospitals are expected. Particularly, because of anthropomorphism, helpful design for humanity, application of positioning and movement, and so on, powerfully expected to manufacture of humanoid robots [1]. Present control techniques to locomotion of robotic legged depends on centralized planning and path follow or corresponding motion pattern. Central control is not available to the robotic help devices that make integration with humans, and correspond to predefined patterns strongly limits from user ability. By difference, biological systems show big legged ability even when the system of the central nervous is separated from spinal cord that belong to these legged, pointing that feedback controls of neuromuscular is harnessed for encoding stability, compatibility, and maneuverability into robotic legged systems [2]. Currently, control systems design is done by a big number of requirements caused by augmentation of competition, requirements of environment, energy and the costs of components and the request for robustness, system of error tolerance. These considerations introduce extra Ekhlas H. Karam Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 145- 155 (2018) 146 needs for effective process modeling techniques. Several systems are not agreeable to traditional modeling approaches, caused when the precision is not found, about the system having formal knowledge, caused from strong behavior for nonlinearities, big degree of suspicion, or variance characteristic of the time [3]. Neural networks and fuzzy logic systems are recently used for different control problems with acceptable results. Both the neural networks and fuzzy logic systems are general approximations caused several adaptive control strategies for nonlinear systems that used fuzzy logic systems, or neural networks have been introduced to get more control performance [4]. As two important strategies of artificial intelligence, fuzzy logic systems and Artificial Neural Networks (ANNs) have several applications in different fields such as availability of product, control systems, diagnostic, observation, etc. They developed and became better throughout the years for adaptation of the rising requirements and the develop of technology. While these two controllers have been frequently used together, explain that the concept of a fusion began to take shape [5]. The neuro-fuzzy system is more efficient and more effective than either neural network or fuzzy logic system which has been widely applied in control systems, pattern recognition, medicine, expert system, and etc. The advantage of this controller is the dealing with it more quickly than other traditional controllers [6]. Different types of neuro-fuzzy have been shown in the literature. These types can be determined depend on the structure of the neuro- fuzzy, the fuzzy model used, and the learning algorithm taken. On the first hand, corresponding to the neuro-fuzzy structure and learning algorithm, the most usually used and successful technique is the feed-forward and recurrent structure model using the BP learning algorithm. On the other hand, according to the fuzzy model taken, two types of fuzzy models are merged with a neural network to form a neuro-fuzzy. These two models are familiar as Takagi and Sugeno model and the Mamdani-model. However, Mamdani-model based NNF represent more obvious neuro-fuzzy systems compared with TS- model based NNF [7]. A simple hybrid neural fuzzy controller is designed in this paper for human robotic leg model, this controller consist from single node neural integral derivative (NID) controller and single input single output fuzzy proportional derivative (FPD) controller with nine rules. The details for this design will be explained in the sections of this paper. 2. Human Robotic Leg Mathematical Model The human robotic leg can by modeled depend on the relation between the input torque that generated by the muscle of the leg and the output of the angular rotation around the hip joint [8]. A simplified human robotic leg cylindrical model is shown in Fig. 1. Fig. 1. Human a robotic leg cylindrical model [9]. The parameters of Fig. 1 are defined by Table 1. Table 1, The parameters of human robotic leg model. The nonlinear equation of the dynamic model for the robotic human leg can be written as follows [9, 10]: � ������ � � ���� � � � � �� � ����� … (1) Where: Mg �� sinθ is the component of weight, D ��� is the damping torque and "� �� ��� # is the inertia torque. The state space for Eq. (1) is: Symbol Description values Tm torque supplied by DC motor D viscous damping 0.1Nms/ra d J inertia around the hip joint 0.4 kgm2/s2 M mass of the leg 1 kg g acceleration due to gravity creates a nonlinear torque 9.81 L the length of the leg and the weight can be determine as L/2 0.5m Ekhlas H. Karam Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 145- 155 (2018) 147 $%&'%�' ( � ) 0 1 ,� &-& ./ �0 � �%&� , "10 #2 3 %&%�4 � ) 0& 0 2 �� 5 � 61 07 3%&%�4 … (2) Where: x1, x2 is robotic leg angular position and velocity respectively. Eq. (1) can be linearized for small angle approximation, the � variation is small; therefore sinθ can assume equal � (i. e. sinθ � �� so Eq. (1) becomes: � ������ � � ���� � � �� � ����� … (3) The linear transfer function of Eq. (3) is given by: ��8� 9�8� � : ; 8�<=; 8<>?@�; … (4) With parameter given by Table 1, Eq. (4) becomes: ��8� 9�8� � �.B8�