Position Sensitive Detector Sensor Research Articles

Development of a Six-Degree-of-Freedom Analog 3D Tactile Probe Based on Non-Contact 2D Sensors.

In this paper, a six-degree-of-freedom analog tactile probe with a new, simple, and robust mechanical design is presented. Its design is based on the use of one elastomeric ring that supports the stylus carrier and allows its movement inside a cubic measuring range of ±3 mm. The position of the probe tip is determined by three low-cost, noncontact, 2D PSD (position-sensitive detector) sensors, facilitating a wider application of this probe to different measuring systems compared to commercial ones. However, several software corrections, regarding the size and orientation of the three LED light beams, must be carried out when using these 2D sensors for this application due to the lack of additional focusing or collimating lenses and the very wide measuring range. The development process, simulation results, correction models, experimental tests, and calibration of this probe are presented. The results demonstrate high repeatability along the X-, Y-, and Z-axes (2.0 µm, 2.0 µm, and 2.1 µm, respectively) and overall accuracies of 6.7 µm, 7.0 µm, and 8.0 µm, respectively, which could be minimized by more complex correction models.

Vehicular Visible Light Positioning System Based on a PSD Detector.

In this paper, we explore the use of visible light positioning (VLP) technology in vehicles in intelligent transportation systems (ITS), highlighting its potential for maintaining effective line of sight (LOS) and providing high-accuracy positioning between vehicles. The proposed system (V2V-VLP) is based on a position-sensitive detector (PSD) and exploiting car taillights to determine the position and inter-vehicular distance by angle of arrival (AoA) measurements. The integration of the PSD sensor in vehicles promises exceptional positioning accuracy, opening new prospects for navigation and driving safety. The results revealed that the proposed system enables precise measurement of position and distance between vehicles, including lateral distance. We evaluated the impact of different focal lengths on the system performance, achieving cm-level accuracy for distances up to 35 m, with an optimum focal length of 25 mm, and under low signal-to-noise conditions, which meets the standards required for safe and reliable V2V applications. Several experimental tests were carried out to validate the results of the simulations.

Precision Laser Beam Path Tracking Control System for Position Measurement Using PSD Sensor

Position sensitive detector (PSD) is an optical position sensor that can measure a position of the light spot in one or two-dimensions on sensor surface. The PSD is precision semiconductor optical sensor that produces output currents related to the “Centre of mass’’ of light incident on the surface of the device used in the measurement there are many advantages including a good positioning accuracy for fast response time and very simple signal conditioning circuits. A precise control system has been designed in this paper using a new and modern algorithm with a closed-loop system to obtain accurate tracking of the position and speed of the radiation used in the measurement of the specific physical process. The proposed control model about laser beam path controlled using a new type of controller named PSD fuzzy controller with feedback through PSD sensor, also the FOC method was applied to the hybrid stepper motor to control the position and speed with four rings feedback. The algorithm will realize better rise time and less overshoot better and detailed analysis is carried out to confirm the viability of the proposed system.

Lens-less PSD measurement of flexible link deflection

Accurate measurement of change in tip position and orientation of flexible links is of substantial importance for flexible robot control applications. In this paper, a measurement system is proposed to measure the change in position and orientation at the tip of a link subjected to bending and torsion with the use of position sensitive detector (PSD) sensors for space applications. Contrary to existing methods for measuring the spatial deflection of a flexible robot, the proposed method eliminates the requirement of a fragile lens or prism to obtain the angular displacement when PSD sensors are used. Experimental results for measuring five variables are presented for a cantilever flexible link when subjected to bending and torsion under a static load, thereby demonstrating the effectiveness of the proposed method.

자율주행 이동로봇의 실시간 장애물 회피 및 안드로이드 인터페이스 구현

In this paper we present an real-time obstacle avoidance technique of autonomous mobile robot with steering system and implementation of user interface for mobile devices with Android platform. The direction of autonomous robot is determined by virtual force field concept, which is based on the distance information acquired from 5 ultrasonic sensors. It is converted to virtual repulsive force around the autonomous robot which is inversely proportional to the distance. The steering system with PD(proportional and derivative) controller moves the mobile robot to the determined target direction. We also use PSD(position sensitive detector) sensors to supplement ultrasonic sensors around dead angle area. The mobile robot communicates with Android mobile device and PC via Ethernet. The video information from CMOS camera mounted on the mobile robot is transmitted to Android mobile device and PC. And the user can control the mobile robot manually by transmitting commands on the user interface to it via Ethernet.

High speed 3D Light Source Position Detection by Combining a 2D PSD and an Ultrasonic Sensor Unit

In this paper, we proposed a high speed method for 3D object tracking which combining a 2D PSD(Position Sensitive Detector) sensor and ultra sonic sensor distance measurement unit. In recent, 2D touch panel equipped products are widely spread. Many operating interface such as a button type remote controller are replace by 2D touch panel. However, such a 2D touch panel cannot be placed easily for an non-original-panel- equiped device due to the size and shape of a 2D panel is fixed, and cannot be customized by an end user. To solve this problem, we proposed a 3D touch panel using object tracking technique. 3D touch panel provides a virtual touch on a space, the size of panel and virtually assigned buttons are not dependent on the size of the device. Moreover, intuitive operation becomes possible. Using a combination of 2D PSD sensor and ultrasonic sensor, the device can be manufactured to a very small size, and the 3D coordinates of the object’s position can be obtained in a high accuracy. The simulation results show that the proposed system contribute a good performance.

Multiple mobile robots system with network-based subsumption architecture

In this paper, a unique multiple mobile robots system is proposed to enable engineering students and engineers in the field to efficiently learn subsumption architecture and develop swarm intelligence. The subsumption architecture is known as one of the behaviour-based artificial intelligence. Each of multiple mobile robots within the system has three wheels driven by DC motors and six position sensitive detector (PSD) sensors. Network-based subsumption architecture is considered to realise a schooling behaviour by using only information from the PSD sensors. Further, a server supervisory control is introduced for poor hardware platforms with limitations of software development, i.e., the mobile robots can only behave based on the most simply subdivided reaction behaviours, i.e., reflex actions, generated from agents. Experimental results show interesting behaviour among the multiple mobile robots, such as following, avoidance and schooling.

Intensity Control of Triangulation Based PSD Sensor Independent of Object Color Variation

Intensity control of triangulation based position sensitive detector(PSD) sensor is addressed to achieve high linearity against object color variation. The controlled signal is added to the pulse amplitude modulation (PAM) signal of the PSD in order to have the beam intensity of photo diode be regulated constant. The control performance for object color variation is compared with the result when intensity control is not applied. Analytical and experimental results indicate that intensity control provides more accurate and higher linearity than that of PSD sensor without using the intensity control by using analysis and experiments.

Cooperative swarm control for multiple mobile robots using only information from PSD sensors

Recently, many studies on swarm robotics have been conducted in which the aim seems to be the realization of an ability to perform complex tasks by cooperating with each other. Future progress and concrete applications are expected. The objective of this study was to construct a cooperative swarm system by using multiple mobile robots. First, multiple mobile robots with six position-sensitive detector (PSD) sensors were designed. A PSD sensor is a type of photo sensor. A control system was considered to realize swarm behavior, such as that shown by Ligia exotica, by using only information from the PSD sensors. Experimental results showed interesting behavior among the multiple mobile robots, such as following, avoidance, and schooling. The controller of the schooling mode was designed based on subsumption architecture. The proposed system was demonstrated to high school students at OPEN CAMPUS 2010, held in Tokyo University of Science, Yamaguchi.

Vibration measurement system based on position sensitive detector

PurposeVibration measurement is needed in many industrial production processes, such as equipment monitoring, fault diagnosis, and noise analysis and eliminating and so on. The purpose of this paper is to propose a simple vibration testing system which includes the laser, the string, position sensitive detector (PSD) and the corresponding signal processing circuit.Design/methodology/approachPSD is an optical semiconductor sensor that can fast locate the luminous spot position precisely, which means that it can output different electric current according to the luminous spot at different position of its surface. Moreover, the experiment on PSD sensor using different vibration source and frequency had been carried out. Finally, the vibration waveform of the luminous spot on PSD photosurface was obtained.FindingsAccording to the experimental results, each kind of vibration parameter with different vibration source, such as vibration frequency and amplitude can be calculated.Originality/valueThe experimental results agreed with the actual parameter, which showed PSD not only had its own good qualities in the position measurement, but also had the unique superiority in the vibration measurement.

주행 오차 보정을 통한 장애물 극복 신경망 제어기 설계

An obstacle avoidance method for a mobile robot is proposed in this paper. Our research was focused on the obstacles that can be found indoors since a robot is usually used within a building. It is necessary that the robot maintain the desired direction after successfully avoiding the obstacles to achieve a good autonomous navigation performance for the specified project mission. Sensors such as laser, ultrasound, and PSD (Position Sensitive Detector) can be used to detect and analyze the obstacles. A PSD sensor was used to detect and measure the height and width of the obstacles on the floor. The PSD sensor was carefully calibrated before measuring the obstacles to achieve better accuracy. Data obtained from the repeated experiments were used to plot an error graph which was fitted to a polynomial curve. The polynomial equation was used to navigate the robot. We also obtained a direction-error model of the robot after avoiding the obstacles. The prototypes for the obstacle and direction-error were modeled using a neural network whose inputs are the obstacle height, robot speed, direction of the wheels, and the error in direction. A mobile robot operated by a notebook computer was setup and the proposed algorithm was used to navigate the robot and avoid the obstacles. The results showed that our algorithm performed very well during the experiments.

단일 PSD를 이용한 실시간 3차원 모션캡쳐 시스템 개발

Motion capture systems are gaining popularity in entertainment, medicine, sports, education, and industry, with animation and gaming applications for entertainment taking the lead. A wide variety of systems are available for motion capture, but most of them are complicated and expensive. In the general class of optical motion capture, two or more optical sensors are needed to measure the 3D positions of the markers attached to the body. Recently, a 3D motion capture system using two Position Sensitive Detector (PSD) optical sensors was introduced to capture high-speed motion of an active infrared LED marker. The PSD-based system, however, is limited by a geometric calibration procedure for two PSD sensor modules that is too difficult for common customers. In this research, we have introduced a new system that used a single PSD sensor unit to obtain 3D positions of active IR LED-based markers. This new system is easy to calibrate and inexpensive.

선형화 전압-거리 변환함수를 이용한 PSD 센서기반 거리계측시스템의 개발

본 논문에서는 이동로봇의 저가형 위치인식센서로 적합한 PSD(Position Sensitive Detector)센서를 이용하여 거리계측시스템을 개발하였다. PSD 센서는 거리-전압 출력이 비선형적인 단점을 가지고 있어 센서의 특성실험을 통해 선형화가 가능한 변환함수를 제안하였다. 제안한 방법을 검증하기 위하여 거리계측시스템의 하드웨어 및 소프트웨어를 구성하였다 또 피측정체의 색상 및 재질에 따른 출력특성을 실험하고 거리-전압 데이터를 측정하였다. 실측한 데이터를 바탕으로 제안한 선형화함수의 계수를 추출하였다. 마지막으로 제안한 함수에 의한 거리와 실제거리를 비교하여 시스템의 성능 및 정확성을 검증하였다. In this paper, a distance measuring system using a PSD sensor in proposed, which in suitable for low-cost localization sensor of a mobile robot. Because the distance-voltage output of PSD sensor has a non-linear property, the linearizing function is proposed through the experimental characteristics of the sensor. And the characteristics are tested and the distance-voltage data are measured in various colors and materials of object. The parameters of the proposed function are extracted by using the measured data. Finally, the performance and the accuracy of the developed system are verified according to the comparison of the distance by the proposed function with the real distance.

Signal processing algorithm of a position sensitive detector using amplitude modulation/demodulation

The signal processing algorithm for a position sensitive detector (PSD) using an amplitude modulation/demodulation algorithm is addressed in this article. Dark currents and the external noises such as daylight and fluorescent lights are eliminated by using the amplitude modulation/demodulation and a low pass filter. The proposed amplitude modulation/demodulation method for the PSD sensor is compared with a pulse amplitude modulation method (PAM). The proposed amplitude modulation method is proved to be more accurate and robust than the PAM method by using analysis and experiments. Multiple measurements technique using one PSD sensor by the amplitude modulation/demodulation is also addressed. The power variation of light source is compensated by the normalization process using a divider.

Signal Processing Algorithm for a PSD Sensor Using an Amplitude Modulation/Demodulation

The signal processing algorithm for a PSD(Position Sensitive Detector) using an amplitude modulation/demodulation algorithm is addressed in this paper. Dark currents and the external noises such as daylight and fluorescent lights are eliminated by using the amplitude modulation/demodulation and a low pass filter. The proposed amplitude modulation/demodulation method for the PSD sensor is compared with a pulse amplitude modulation method. The proposed amplitude modulation method is proved to be more accurate and robuster than the PAM method by using analysis and experiments. Multiple measurements technique using one PSD sensor by the amplitude modulation/demodulation is also addressed. The power variation of light source is compensated by the normalization process using a divider.

Real-Time Dynamic Visual Tracking Using PSD Sensors and Extended Trapezoidal Motion Planning

A real-time visual servo tracking system for an industrial robot has been implemented using PSD (Position Sensitive Detector) cameras, neural networks, and an extended trapezoidal motion planning method. PSD and directly transduces the light‘s projected position on its sensor plane into an analog current and lends itself to fast real-time tracking. A neural network, after proper training, transforms the PSD sensor reading into a 3D position of the target, which is then input to an extended trapezoidal motion planning algorithm. This algorithm implements a continuous motion update strategy in response to an ever-changing sensor information from the moving target, while greatly reducing the tracking delay. This planning method is found to be very useful for sensor-based control such as moving target tracking or weld-seam tracking in which the robot needs to change its motion in real time in response to incoming sensor information. Further, for real-time usage of the neural net, a new architecture called LANN (Locally Activated Neural Network) has been developed based on the concept of CMAC input partitioning and local learning. Experimental evidence shows that an industrial robot can smoothly track a moving target of unknown motion with speeds of up to 1 m/s and with oscillation frequency up to 5 Hz.