Kinematic Kalman Filter (KKF) for Robot End-Effector Sensing

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Soo Jeon ◽  
Masayoshi Tomizuka ◽  
Tetsuaki Katou
Keyword(s):  
Kalman Filter ◽  
High Speed ◽  
High Performance ◽  
Control Strategies ◽  
Sampling Rate ◽  
Body Motion ◽  
Vision Sensor ◽  
End Effector ◽  
Measurement Delay ◽  
Velocity Information

In control of industrial manipulators, the position from the motor encoder has been the only sensor measurement for axis control. In this case, it is not easy to estimate the end-effector motion accurately because of the kinematic errors of links, joint flexibility of gear mechanisms, and so on. Direct measurement of the end-effector using the vision sensor is considered as a solution but its performance is often limited by the slow sampling rate and the latency. To overcome these limitations, this paper extends the basic idea of the kinematic Kalman filter (KKF) to general rigid body motion leading to the formulation of the multidimensional kinematic kalman filter (MD-KKF). By combining the measurements from the vision sensor, the accelerometers and the gyroscopes, the MD-KKF can recover the intersample values and compensate for the measurement delay of the vision sensor providing the state information of the end-effector fast and accurately. The performance of the MD-KKF is verified experimentally using a planar two-link robot. The MD-KKF will be useful for widespread applications such as the high speed visual servo and the high-performance trajectory learning for robot manipulators, as well as the control strategies which require accurate velocity information.

A New Kinematic Kalman Filter (KKF) for End-Effector Sensing of Robotic Manipulators

2007 ◽  
Author(s):  
Soo Jeon ◽  
Masayoshi Tomizuka ◽  
Tetsuaki Katou
Keyword(s):  
Kalman Filter ◽  
Real Time ◽  
Sampling Rate ◽  
Accurate Estimation ◽  
Vision Sensor ◽  
Direct Drive ◽  
State Estimator ◽  
Parameter Uncertainties ◽  
End Effector ◽  
The Real

The kinematic Kalman filter (KKF) is a sensor-based state estimator which is immune to the external disturbances and the parameter uncertainties of mechanical plants. This paper extends the original idea of the KKF to a more general form as a means to enhance a real time vision sensor for the end-effector control of a robot manipulator, the performance of which is often limited by its slow sampling rate. The original one-dimensional KKF is reformulated in a higher dimensional form by incorporating the measurements from the vision sensor, accelerometers and gyroscopes. A nonlinear state space model of the kinematics of the end-effector is derived including the time delay associated with vision sensing. Then, the new KKF is formulated as a state estimator combining the inter-sample predictions with an extended Kalman filter (EKF). The paper discusses practical issues such as the real time computation to implement the EKF and the vision sensor to measure the absolute position. Experimental results are presented to confirm the benefits of the new KKF using a two-link direct drive manipulator equipped with a dual axis MEMS accelerometer, a single axis MEMS gyroscope and an end-effector mounted vision camera. The accurate estimation of the position and velocity of the end-effector from the new KKF will be useful for the real time visual-servo and the task space control of robot manipulators.

Inertial and Vision Sensor Based End-Effector Sensing and Control for Robot Manipulators

2010 ◽  
Author(s):  
H. Cheng ◽  
M. Tomizuka
Keyword(s):  
Kalman Filter ◽  
Tracking Control ◽  
Robot Manipulators ◽  
Industrial Robot ◽  
Sampling Rate ◽  
Direct Drive ◽  
End Effector ◽  
Velocity Information ◽  
Accurate Position ◽  
And Control

In the application of industrial robot manipulators, it is often desirable to obtain accurate position and velocity information regarding the end-effector. Estimations based on motor-side encoders alone are often inaccurate due to joint flexibilities and errors in the robot link kinematics. A vision based approach may also be insufficient due to its low sampling rate and image processing and transportation delay. However, with additional accelerometer measurements, a kinematic Kalman filter (KKF) can be formulated to estimate the end-effector motion accurately without encoder signals. The estimation results can be utilized for real time tracking control effectively. In this paper a multirate kinematic Kalman filter (KKF) scheme is formulated using vision and acceleration measurements from the end-effector. Estimations based on the scheme are utilized as feedback signals for tracking control. The effectiveness of the proposed approach is demonstrated by experiments on a single joint direct drive setup.

scholarly journals Propeller control strategy for coaxial compound helicopters

2018 ◽  
Vol 233 (10) ◽  
pp. 3775-3789 ◽  
Author(s):  
Ye Yuan ◽  
Douglas Thomson ◽  
Renliang Chen
Keyword(s):  
Control Strategy ◽  
High Speed ◽  
High Performance ◽  
Control Strategies ◽  
Flight Dynamics ◽  
Axial Thrust ◽  
Handling Qualities ◽  
Speed Range ◽  
Compound Helicopter ◽  
Flight Dynamics Model

The coaxial compound configuration has been proposed as a concept for future high-performance rotorcraft. The co-axial rotor system does not require an anti-torque device, and a propeller provides axial thrust. A well-designed control strategy for the propeller is necessary to improve the performance and the flight dynamics characteristics. A flight dynamics model of coaxial compound helicopter is developed to analyze these influences. The performance and the flight dynamics characteristics in different propeller strategies were first investigated. The results show that there is an improvement in the performance in high-speed flight when the propeller provides more propulsive forces. It also illustrates that a reasonable allocation of the rotor and the propeller in providing thrust can further reduce the power consumption in the mid speed range. In other words, the propeller control strategy can be an effective method to improve the cruise-efficiency. The flight dynamics analysis in this paper includes trim and handling qualities. The trim results prove that the propeller strategy can affect the collective pitch, longitudinal cyclic pitch, and the pitch attitude. If the control strategy is designed only to decrease the required power, it will result in a discontinuity in the trim characteristics. Handling qualities are investigated based on the ADS-33E-PRF requirement. The result demonstrates that the bandwidth and phase delay results and eigenvalue results in various speed at different propeller strategies are all satisfied. However, some propeller control strategies lead to severe inter-axis coupling in high-speed flight. Based on these results, this paper proposes the propeller control strategy for the coaxial compound helicopter. This strategy ensures good trim characteristics and handling qualities, which satisfy the related requirements, and improves the flight range or the performance in high-speed flight.

scholarly journals High-Speed Handling Robot with Bionic End-Effector for Large Glass Substrate in Clean Environment

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 149
Author(s):  
Zhengyong Liu ◽  
Youdong Chen ◽  
Henan Song ◽  
Zhenming Xing ◽  
Hongmiao Tian ◽  
...  
Keyword(s):  
High Precision ◽  
Glass Substrate ◽  
High Speed ◽  
High Performance ◽  
Large Scale ◽  
Dynamic Models ◽  
Low Cost ◽  
Structure Design ◽  
End Effector ◽  
Vibration Experiment

The development of “large display, high performance and low cost” in the FPD industry demands glass substrates to be “larger and thinner”. Therefore, the requirements of handling robots are developing in the direction of large scale, high speed, and high precision. This paper presents a novel construction of a glass substrate handling robot, which has a 2.5 m/s travelling speed. It innovatively adopts bionic end-suction technology to grasp the glass substrate more firmly. The structure design is divided into the following three parts: a travel track, a robot body, and an end-effector. The manipulator can be smoothly and rapidly extended by adjusting the transmission ratio of the reducer to 1:2:1, using only one motor to drive two sections of the arm. This robot can transfer two pieces of glass substrate at one time, and improves the working efficiency. The kinematic and dynamic models of the robot are built based on the DH coordinate. Through the positioning accuracy experiment and vibration experiment of the end-effector, it is found that the robot has high precision during handling. The robots developed in this study can be used in large-scale glass substrate handling.

scholarly journals A 6-bit Low-Power High-Speed Flash ADC using 180 nm CMOS process

2014 ◽  
Vol 17 (1) ◽  
pp. 52-61
Author(s):  
Thanh Tri Vo ◽  
Trong Tu Bui ◽  
Duc Hung Le ◽  
Cong Kha Pham
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
High Speed ◽  
High Performance ◽  
Sampling Rate ◽  
Low Power Consumption ◽  
Cmos Process ◽  
Flash Adc ◽  
High Sampling Rate ◽  
Simulation Results

In this paper we present a design of Flash-ADC that can achieve high performance and low power consumption. By using the Double Sampling Rate technique and a new comparator topology with low kick-back noise, this design can achieve high sampling rate while still consuming low power. The design is implemented in a 0.18 m CMOS process. The simulation results show that this design can work at 400 MSps and power consumption is only 16.24 mW. The DNL and INL are 0.15 LSB and 0.6 LSB, respectively.

Workspace Analysis of a Hybrid-Driven Cable Parallel Mechanism

2011 ◽  
Vol 66-68 ◽  
pp. 802-806 ◽  
Author(s):  
Zi Bin ◽  
Jian Bin Cao
Keyword(s):  
Parallel Mechanism ◽  
High Speed ◽  
High Performance ◽  
Analysis Method ◽  
End Effector ◽  
Workspace Analysis ◽  
Motion Range ◽  
New Type ◽  
Main Factors ◽  
High Payload

This paper presents a new-type hybrid-driven cable parallel mechanism, which combines hybrid-driven mechanism with cable parallel mechanism, and the mechanism can not only operate with high speed, high accuracy, and high payload, but also have high performance output movement. The workspace of hybrid-driven cable parallel mechanism is characterized as the space where the end-effector can reach with tensions in all cables, and it is studied in this paper. Firstly, through the kinematic analysis, it can be derived the location equations of the end-effector. Then, the paper analyzes the main factors influencing the workspace of hybrid-driven cable parallel mechanism such as cable tension, workspace of hybrid-driven mechanism, the length of cables, and the motion range. At the end, with the location equations and constraints, the workspace is determined. Computational example is provided to demonstrate the effectiveness of the proposed analysis method.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

PHAX-SCAN: Functional integration of a Scanning Electron Microscope and an energy-dispersive x-ray analyser

1989 ◽  
Vol 47 ◽  
pp. 56-57
Author(s):  
Marc H. Peeters ◽  
Max T. Otten
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
Functional Integration ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
High Speed Analysis ◽  
Scanning Electron

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.

The bright future of digital imaging in scanning electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 768-769
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Digital Imaging ◽  
High Speed ◽  
High Performance ◽  
Mass Storage ◽  
Analog To Digital ◽  
Central Processing ◽  
Digital Imaging Technology ◽  
Scanning Electron

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.

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