Development of high performance servo drive/anti drive mechanism for backlash removal
Keywords: 1 Degree of freedom Platform, Backlash Removal, System Modelling. Abstract: In electromechanical drives, there is always a backlash between any pair of gears. Because of this, it is almost impossible to realize a high accuracy and high performance drive. However such drives are crucial in today’s modern electromechanical systems. A high performance drive/anti-drive servo mechanism is developed to eliminate the effect of backlash. The concept utilizes redundant unidirectional drives to assure positive coupling of gear meshes at all times. Based on this concept, a methodology for enumeration of admissible redundant-drive backlash free mechanism has been established. The angular displacement is achieved as a difference of two torques. These torques can be controlled by a high performance control system. A controller model will be designed to move a single degree of freedom platform up to a desired span with a payload.
Development of a 2 degrees of freedom tracking system: design and fabrication of platform
This paper reports the design and fabrication of an innovative 2-DOF robotic platform for precision pointing and image-based tracking applications. Conventionally, such platforms have very simple structures but have various associated limitations. One such problem is the generally imbalanced structure due to the placement of the elevation actuator on moving base. This design causes a lot of problems when platform is operated at high angular velocities. This paper, however, proposes a new design that is balanced in structure and very light due to placement of both actuators in the stationary base, hence finding its applications in high speed tracking problems. This thing in return has caused coupling between the two degrees of freedom. However, it is a kinematics problem and can be resolved easily in the control algorithm.
An edge based visual tracking for target within complex environment
In this paper, a visual tracking system is proposed. The whole system is divided into two parts. The first part is the detection of the target and the second part is the trajectory filtering. To detect the target in the image, we use the method based on the distribution of edges. In this method, the template is edge based, and the distribution of edges of the image is extracted, so that the two are convolved to find the location of the target. The method is more reliable than the traditional template matching in the complicated scene. After finding the target in the image, we will control the camera platform to keep the target at the center of the image. The location of the target in the world coordinate frame is first transformed to the orientation relative to the camera whereby a tracking algorithm based on the IMM (interacting multiple model) algorithm is developed. The algorithm estimates the angular velocity and the angular acceleration of the target relative to the camera, which along with some error information in the images are used for control of the camera platform. Finally, a number of experiments are conducted to validate the developed visual tracker.