Erol Uyar

Modelling of an Under-Hip Prosthesis with Ankle and Knee Trajectory Control by Using Human Gait Analysis

Abstract In this paper, depending on bipedal human walking analysis, knee and ankle joint control of special under-hip prosthesis is investigated. After the designing of the prosthesis and its parts by using SolidWorks, strength analyses under various pedestal loads are given, to ensure an optimal and convenient model. Depending on measurements of hip, knee and ankle motions by using vision techniques, bipedal human gait analysis is investigated. After these measurements using the hip motion as reference, knee and ankle joint angles are derived and calculated.The calculated values are then used to control the motions of knee and ankle joints via DC-motors so that the investigated trajectories for optimal bipedal walking could be realized. A mathematical model for bipedal walking is then executed as a combination of two serial manipulators, each having two revolute joints, in other words, having two degrees of freedom. Inverse kinematics analysis and recursive Newton-Euler computation methods are given to obtain the dynamic equations, which describe the motion of the walking system. For desired walking characteristics, knee and ankle trajectories are derived. With this novel method both ankle and knee joint positions in case of upper knee amputees can be determined and controlled for various gait instants.

Indoor Navigation and Guidance of an Autonomous Robot Vehicle by Using Wireless (ZigBee) Cummunication

In this work, a novel approach for navigation and guidance of a duo cycle autonomous robot vehicle by using ZigBee wireless control is presented. For navigation the angular position and location of the vehicle is measured intermittent by means of an electronic compass and a linear position encoder. Both measured values are then compared through a PC with the reference points of a certain trajectory, so that a given path can be followed by the vehicle autonomously. Besides navigation a self developed algorithm is integrated to the system control for possible obstacle avoidance and optimal path finding. The results of experimental testing showed the effectiveness of the proposed approach.

Design and control of a mobile manipulator with stereo vision guidance

Using vision based control, two different control types for mobile platform and manipulator is applied. Mobile platform is controlled with a hybrid visual servo controller. Its instantaneous linear velocity is controlled via position based visual servoing and its angular velocity is controlled via image based visual servoing. Manipulator motion is controlled through dynamic look and move control strategy. Control of the mobile manipulator is done by task sequencing. A task is separated into two parts: Mobile platform moves till target is placed in manipulator workspace afterwards manipulator moves to hold target. Experimental results demonstrates success of control system in autonomus positioning tasks.

Navigation and GPS based path control of an autonomous vehicle

In this work the navigation and GPS based trajectory control of an unmanned autonomous vehicle is introduced. The caterpillar tread like mobile vehicle with duo cycle drive is equipped with a mobile GPS and micro controller. To get accurate position data, a DGPS (Differential GPS) with a local base station is used. In order to let the vehicle to follow a desired trajectory, a reference path is given by using Way Points as GPS datas to micro controller, which provide the position and orientation control of the vehicle. The instant position and orientation of the vehicle in accordance to an assigned plane coordinate frame are calculated by micro controller from detected latitude and longitude values (land coordinates) of mobile GPS, which receive corrected on line datas from base station.The duo cycle vehicle is driven with geared DC motors, which are equipped with chained caterpillar tread drives, so that it can have better motion, clambering and tracking performances. Successful navigation and path following results are obtained with several experiments by various control applications.

IFAC Workshop on Advances in Control and Automation Theory for Transportation Applications Guidance and Control of an Unmanned Holonomic Robot for Transport Applications

Abstract In this work, indoor guidance and control of an autonomous holonomic transport robot vehicle via wireless (ZigBee) communication modules is presented. The vehicle modified as a mini forklift is equipped with four mecanum wheels which are separately driven with geared DC- Motors. In this configuration it has the capability of moving omnidirectional and to work even in very narrow areas. For indoor guidance and control of the autonomous unmanned vehicle (AUV), a remote control system existing of ZigBee wireless RF Modules, a PC as main controller and Ardupilot Mega (APM) microcontroller kit is implemented. Stationary PC as main controller can guide the vehicle to follow a calculated path autonomously through bilateral data transmission between APM and PC. As control data the angular position (yaw angle) is detected through integrated IMU (Inertial Measuring Unit) of APM and as second control parameter linear position is measured by an encoder. Besides navigation a self developed algorithm is integrated to the system for possible obstacle avoidance and optimal path finding. A Sharp distance sensor is used to detect distance and obstacles in the environment. Through integrated IMU and GPS system of APM the vehicle can be used for both indoor and outdoor applications. The results of experimental testing showed the effectiveness of the proposed approach.

Position control of a seesaw like platform by using a thrust propeller

This paper presents the design and position control of a seesaw like supported beam which angular motion is measured by an encoder and controlled by the draft force of a propeller at end of the beam. After the general mechanical design and modelling the system, dynamic equations and parameters are investigated and all parts are drawn in SolidWorks, so that the real weights and inertias for the simulation of the motion and a real implementation with reasonable control application could be done. Classic control algorithms such as P, PI, Pd and PID are applied to the real model with various parameters and the obtained results are compared. On the other hand a MATLAB model of the system is derived and simulation results of this model are then compared with real implementation results. Very closed results approved the success of the model with real implementation.

Indoor Navigation and Guidance of an Autonomous Robot Vehicle with Static Obstacle Avoidance and Optimal Path Finding Algorithm

Abstract This work, presents an application for static obstacle avoidance and optimal path finding of an autonomous robot vehicle with navigation and control. Angular position and location of the vehicle is measured intermittent by means of an electronic compass sensor and a linear position encoder for the navigation purposes. Vehicle movements and orientation is controlled real time by a stationary computer. Besides navigation a self developed algorithm is integrated to the system for static obstacle avoidance and optimal path finding. An environmental map to detect the static obstacle positions are pre-defined and different maps depended on working area are evaluated by using a suitable computer program. To guide the vehicle to a given target, an optimal path calculation algorithm is applied. During high level control operations are executed by the computer, low level operations are made by a microcontroller to minimize time depended errors. The results and simulations of experimental testing showed the effectiveness of the proposed approach for navigation applications.

Control and Navigation of an Autonomous Mobile Robot with Dynamic Obstacle Detection and Adaptive Path Finding Algorithm

Abstract In this work, a novel approach for navigation, guidance and control of a duo cycle autonomous robot vehicle with dynamic obstacle avoidance and adaptive path finding algorithm is presented. Real time control and simulation of vehicle movements and orientation is made by a stationary computer. In addition, a self developed algorithm is integrated to the system for dynamic obstacle avoidance and adaptive path finding. Sub-optimal paths to the given target point are calculated simultaneously according to dynamic environment with a written algorithm program. Low level control operations are made by microcontroller to minimize time depended errors. Mobile computer is used to collect laser measurement data and provides the communication between vehicle and control station (stationary pc). Laser measurement sensor is used for simultaneous obstacle detection and environment mapping so that an adaptive like path finding can be realized. The simulations and experimental results showed the effectiveness of the proposed approach for navigation applications with adaptive path finding algorithm.

Dynamic Analysis and Computer Aided Control of a Tripod Parallel Manipulator

Abstract In this paper, modeling, dynamic analysis and position control of a 3-PUU translational parallel manipulator (TPM) is investigated. After the general mechanical design of the manipulator all parts are drawn and modeled in SolidWorks, and a simulation of the motion in three dimensional space is made. For dynamic analysis relevant equations are derived from geometrical relations of the model and finally the forward and inverse kinematic solutions of the non-linear model are developed by using a MATLAB iteration algorithm. Furthermore the transfer functions of the position control system with a block diagram are derived and a control simulation with use of MATLAB Simulink is made. Simulation results are compared with real time system responses and satisfactory results are obtained

Modelling and Kinematic Analysis of a Built Up Linear Delta Robot

In this paper kinematic analysis of a 3-PUU translational parallel manipulator (TPM) is made by creating the forward and inverse Kinematic solutions. For a given position, control of the end effecter is then realized by using the calculated inverse kinematic parameters as reference values. For kinematic analysis relevant equations are derived from geometrical vector relations. For the forward and inverse kinematic solutions of the non-linear model a MATLAB based iterative algorithm is developed and the inverse kinematic solutions of limbs, are then used to control the end effecter position through screw rails which are driven by DC motors. After the general mechanical design of the manipulator all parts are drawn and modelled in SolidWorks, and a simulation of the motion in three dimensional space is made. To support the reliability of calculated parameters through inverse kinematic solutions, results are compared with the values of SolidWorks based simulation model of the manipulator. Furthermore a real position control with use of feed back encoders is applied and the evaluated results are compared with the results of a simulation model. Very similar and satisfactory results are obtained with both simulation and real application.