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Determination of injury rate on fish surface is one of the major cause for increasing quality of fish on the markets. Detecting injury fishes manually is hard work with low efficiently. An image processing method is usually considered to do this work as an online selecting method of injury area. The injury area segmentation of fish image is based on color features with Fuzzy C-means clustering and L*a*b* color space. Although there are many different color spaces. CIE L*a*b* color space of them is most used for detecting fish injury due to its uniform color distribution and is closest to the one human eye. Generally, a fish injury image has overlapped data with fish body image. The K-means clustering algorithm cannot give the good solution to segment whether pixels of the overlapped data belong to fish body or injury area. To solve this problem, this paper is to present the good solution for segmentation of fish injury image with the overlapped data from the fish body image and determine injury rate on fish surface based on Fuzzy C-means clustering and L*a*b* color space using ZED stereo camera. The proposed image processing method is tested on fishes. The experimental results show that the injury rate measured using the proposed image processing method is close to the real injury rate.

This paper presents a Kinect camera sensor-based object tracking and following system for the four wheel independent steering automatic guided vehicle (4WIS-AGV) using Kalman filter and backstepping control method. To accomplish this task, the following steps are executed: Firstly, a blue colored object is detected by the Kinect camera sensor using a color-based object detection method and its center coordinates inside the RGB image frames are obtained. The global position coordinates of the detected object and the 4WIS-AGV are obtained using Kinect depth data and NAV200 navigation system. Secondly, a Kalman filter is used to estimate the global position and velocity coordinates of the detected moving object. Thirdly, a backstepping control method using Lyapunov function is adopted for the 4WIS-AGV to perform the object following task. Finally, simulation and experiment are performed to verify the effectiveness of the proposed system. The results show that the 4WIS-AGV with Kinect camera sensor can follow the moving object well with the designed controller.

This paper introduces omni-directional walking control of a six-legged robot (6LR). The 6LR consists of its body, six legs with four links and four rotational joints. The followings are done for this task. First, the walking gait of the 6LR is chosen. Second, modeling for one leg with four links and four rotational joints of the 6LR is proposed. It is difficult and complex to get the angles of four rotational joints in the case of using inverse kinematics. To solve this problem, differential kinematics algorithm is used to generate omni-directional walking trajectory of a leg based on back-stepping control using Lyapunov stability. Finally, simulation results for walking motion of one leg of the 6LR are shown to prove the effectiveness and applicability of the proposed controller.

This paper proposes a tracking controller for obstacle avoidance of an omni-directional mobile vehicle (OMV) using potential function method through a ceiling-mounted camera system. To do this task, the followings were done. At first, for image processing, a ceiling-mounted camera system was installed to get images. The goal point and obstacles were separated and recognized by a color recognition method. Second, potential function method was proposed to generate the shortest path to avoid obstacles from the start point to the goal point. The mobile platform is a mecanum wheel omni-directional vehicle. Third, the tracking controller is designed for the OMV to track a trajectory generated by a path planning algorithm based on the backstepping method using Lyapunov function. Finally, the simulation results were presented to show the effectiveness of the proposed trajectory planning algorithm and tracking controller for obstacle avoidance of the OMV.

This paper introduces a path tracking controller for six legs control and omni-directional gaits of hexapod robot. The hexapod robot consists of its body and six legs. A leg has three links and three rotational joints. One leg is designed by forward kinematic for mathematic modeling. Path tracking controller is developed based on back-stepping control using Lyapunov stability and tracking reference trajectory of one leg with smooth and uniform velocity. A hardware control system of the hexapod robot is developed based on DSP TMS320F28335 micro-controller and AX-12A servo motors with half duplex communication. The simulation and experimental results are shown to prove the effectiveness and applicability of the applied controller. For experiment, we apply tripod gait to the hexapod robot.

This paper introduces a tracking controller for Automatic Guided Vehicles (AGV) to track a desired trajectory. The use of the nonlinear Lyapunov technique provides robustness for load disturbance and sensor noise. Based on kinematic model, a trajectory tracking controller of AGV is proposed. System stability is verified by Lyapunov stability. A laser sensor device NAV200 is used to detect the AGV position in door environment in real-time. For simulation and experiment, software and hardware are described. The AGV consists of 4 wheels with two passive wheels and two driving wheels. A controller is developed based on industrial computer. The effectiveness of the proposed controller is proved by simulation and experimental results.

In this paper, a sliding-mode observer is applied to control an AC induction motor. First, the modeling of AC induction motor is presented. After that, a sliding mode observer is proposed to estimate the motor speed, the rotor flux, the angular position of the rotor flux and the motor torque from monitored stator voltages and currents. The proposed sliding mode observer provides very good performance for both low and high speed motor operation. Furthermore, the proposed system is robust in motor losses and load variations. The proposed observer does not uses complicated observer gains and it is easy to setup for different types of motor. The convergence of the proposed observer is obtained using the Lyapunov theory. Hardware and software for experiment of the AC induction motor drive are introduced. The experimental results illustrate that fast torque and speed response with small torque ripples can be achieved. The proposed control scheme is suitable to the application fields that require high performance of torque response such as electric vehicles.

This paper proposes an optimal control method for a 10 degree of freedom (DOF) biped robot with stable walking gait. The biped robot is modeled as a 3D inverted pendulum. From dynamic model of the 3D inverted pendulum and under the assumption that center of mass (COM) of the biped robot moves on a horizontal constraint plane, zero moment point (ZMP) equations of the biped robot depending on the coordinate of the center of the pelvis link obtained from the dynamic model of the biped robot are given based on the DdasiaAlembertpsilas principle. A walking pattern is generated based on ZMP tracking control systems that are constructed to track the ZMP of the biped robot to zigzag ZMP reference trajectory decided by the footprint of the biped robot. An optimal tracking controller is designed to control the ZMP tracking control system. From the trajectory of the COM of the biped robot and an arc reference input of the swinging leg, the inverse kinematics solved by the solid geometry method is used to compute the angles of each joint of the biped robot. The simulation and experimental results show the effectiveness of this proposed control method.

A nonlinear constrained model predictive control (NCMPC) method is presented for the control of the dissolved oxygen in a bio-reactor system using Hammerstein model. The control of dissolved oxygen as output is accomplished by adjusting the stirrer speed as input. The proposed controller is compared with the Nonlinear Model Predictive Control(NMPC) method without input constraints. The simulations and experiments are implemented. A control system based on microprocessor PIC16F877 is developed to implement the experiments. The simulation and experimental results show that the performance of the input stirrer speed with input constraints is better than that without input constraints. The effectiveness of the proposed controller is shown through simulations under the known disturbance and variable set-point tracking.

Locomotion employed by legged land quadruped is a complex process. It requires the coordination of multiple degrees of freedom. In addition, locomotion control is complex because it requires: adapting to terrain, optimizing the gait, trying to satisfy multiple constraints, therefore, designing of quadruped robot must determine several related factors, which influences the result of the robot. Among of them, the two most important factors are: the mechanical structure and leg configuration; method of locomotion and the control system. This paper proposes a new approach for designing quadruped robot based on the skeleton of dog and the two above factors: simple mechanical structure and leg configuration are designed to simplify the operation of actuator; quadruped robot can be walked and run in a bounding gait with a simple control system.

This paper considers the control system design for a mobile inverted pendulum via sliding mode technique. Firstly, a linear system is described in order to facilitate the development of an efficient control system. Secondly, sliding mode controllers are developed for stabilizing and tracking this system. Thirdly, the controllers have been implemented on a PIC microcontroller board. Additionally, the simulations were given to prove the validity of the proposed controllers.

This paper proposed a sliding mode control method for a two-wheel welding mobile manipulator to track a smooth 3D curved welding path. To design a tracking controller, the tracking errors are defined between the welding point of the torch and the reference point moving at a specified constant welding speed on the welding path. A sliding surface is set up and a control law is proposed for stabilization of the sliding surface. The simulations are performed to show the effectiveness of the proposed controller.