In a special case of type-2 fuzzy logic systems （FLS）, i.e. geometric inteIval type-2 fuzzy logic systems （GIT-2FLS）, the crisp output is obtained by computing the geometric center of footprint of uncertainly （FO...In a special case of type-2 fuzzy logic systems （FLS）, i.e. geometric inteIval type-2 fuzzy logic systems （GIT-2FLS）, the crisp output is obtained by computing the geometric center of footprint of uncertainly （FOU） without type-reduction, but the defuzzifying method acts against the corner concepts of type-2 fuzzy sets in some cases. In this paper, a PSO type-reduction method for GIT-2FLS based on the particle swarm optimization （PSO） algorithm is presented. With the PSO type-reduction, the inference principle of geometric interval FLS operating on the continuous domain is consistent with that of traditional interval type-2 FLS operating on the discrete domain. With comparative experiments, it is proved that the PSO type-reduction exhibits good performance, and is a satisfactory complement for the theory of GIT-2FLS.展开更多
The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave...The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.展开更多
The centroid coordinate serves as a critical control parameter in motion systems,including aircraft,missiles,rockets,and drones,directly influencing their motion dynamics and control performance.Traditional methods fo...The centroid coordinate serves as a critical control parameter in motion systems,including aircraft,missiles,rockets,and drones,directly influencing their motion dynamics and control performance.Traditional methods for centroid measurement often necessitate custom equipment and specialized positioning devices,leading to high costs and limited accuracy.Here,we present a centroid measurement method that integrates 3D scanning technology,enabling accurate measurement of centroid across various types of objects without the need for specialized positioning fixtures.A theoretical framework for centroid measurement was established,which combined the principle of the multi-point weighing method with 3D scanning technology.The measurement accuracy was evaluated using a designed standard component.Experimental results demonstrate that the discrepancies between the theoretical and the measured centroid of a standard component with various materials and complex shapes in the X,Y,and Z directions are 0.003 mm,0.009 mm,and 0.105 mm,respectively,yielding a spatial deviation of 0.106 mm.Qualitative verification was conducted through experimental validation of three distinct types.They confirmed the reliability of the proposed method,which allowed for accurate centroid measurements of various products without requiring positioning fixtures.This advancement significantly broadened the applicability and scope of centroid measurement devices,offering new theoretical insights and methodologies for the measurement of complex parts and systems.展开更多
In this paper,the Orlicz centroid function for log-concave functions is introduced.A rearrangement inequality of the Orlicz centroid function for log-concave functions is obtained.The rearrangement inequality implies ...In this paper,the Orlicz centroid function for log-concave functions is introduced.A rearrangement inequality of the Orlicz centroid function for log-concave functions is obtained.The rearrangement inequality implies the Orlicz Busemann-Petty centroid inequality of Lutwak,Yang and Zhang[23].展开更多
The precise acquisition of the quality characteristic parameters of large aircraft directly affects its performance characteristics.For large aircrafts such as missiles and rockets with internal fillings,traditional m...The precise acquisition of the quality characteristic parameters of large aircraft directly affects its performance characteristics.For large aircrafts such as missiles and rockets with internal fillings,traditional measurement methods involving large-angle tilting or rotation may pose safety risks.In light of the characteristics of large aircraft and in combination with existing measurement methods,we design a mass and centroid measurement method based on four-point support and small-angle tilting,and develop a set of mass and centroid testing system.This method obtains the intersection point of the gravity action line in the product coordinate system through coordinate transformation in two postures,thereby obtaining the three-dimensional centroid of the aircraft.We first elaborate on the principle of this method in detail,then introduce the composition of the equipment,and analyze the structural stress of key components.Finally,experimental verification and uncertainty analysis are carried out.Experimental verification shows that the maximum deviation of the mass measurement accuracy is less than 0.02%,the centroid measurement accuracy in the X direction is±0.15 mm,in the Y direction it is±0.21 mm,and in the Z direction it is±0.19 mm.展开更多
The problem of disturbance rejection in humanoid robots has been properly studied,with most prior work focusing on hip-ankle-stepping compliance control strategies or whole-body inverse dynamics control.This paper pre...The problem of disturbance rejection in humanoid robots has been properly studied,with most prior work focusing on hip-ankle-stepping compliance control strategies or whole-body inverse dynamics control.This paper presents an adaptive disturbance rejection balance controller based on a Variable-inertia Centroidal Model Predictive Control(ViC-MPC)approach,designed to address both minor disturbances that affect standing balance and major disturbances requiring stepping adjustments.The controller also facilitates reliable balance recovery after stepping adjustments.The humanoid robot is modeled as a spatial variable-inertia ellipsoid,representing the distribution of centroidal dynamics,with the contact wrenches optimized in real-time through a customized MPC formulation.Inspired by capturability-based constraints,we propose an adaptive dynamic stability transition strategy.This strategy is activated based on the Retrospective Horizon Average Centroidal Velocity(RHACV)and the Capture Point(CP),ensuring effective stepping adjustments and disturbance rejection.With the torque-controlled humanoid robot BHR8P,extensive simulation and experimental results demonstrate the effectiveness of the proposed method,highlighting its capability to adapt to and recover from various disturbances with improved stability.展开更多
基金Sponsored by the National Hi-Tech Program of China(Grant No. 2005AA420050)the National Key Technology R&D Program of China(Grant No.2006BAD10A0401, 2006BAH02A01)
文摘In a special case of type-2 fuzzy logic systems （FLS）, i.e. geometric inteIval type-2 fuzzy logic systems （GIT-2FLS）, the crisp output is obtained by computing the geometric center of footprint of uncertainly （FOU） without type-reduction, but the defuzzifying method acts against the corner concepts of type-2 fuzzy sets in some cases. In this paper, a PSO type-reduction method for GIT-2FLS based on the particle swarm optimization （PSO） algorithm is presented. With the PSO type-reduction, the inference principle of geometric interval FLS operating on the continuous domain is consistent with that of traditional interval type-2 FLS operating on the discrete domain. With comparative experiments, it is proved that the PSO type-reduction exhibits good performance, and is a satisfactory complement for the theory of GIT-2FLS.
基金Supported by the Short-wave Infrared Camera Systems(B025F40622024)。
文摘The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.
基金supported by National Natural Science Foundation of China(No.52176122).
文摘The centroid coordinate serves as a critical control parameter in motion systems,including aircraft,missiles,rockets,and drones,directly influencing their motion dynamics and control performance.Traditional methods for centroid measurement often necessitate custom equipment and specialized positioning devices,leading to high costs and limited accuracy.Here,we present a centroid measurement method that integrates 3D scanning technology,enabling accurate measurement of centroid across various types of objects without the need for specialized positioning fixtures.A theoretical framework for centroid measurement was established,which combined the principle of the multi-point weighing method with 3D scanning technology.The measurement accuracy was evaluated using a designed standard component.Experimental results demonstrate that the discrepancies between the theoretical and the measured centroid of a standard component with various materials and complex shapes in the X,Y,and Z directions are 0.003 mm,0.009 mm,and 0.105 mm,respectively,yielding a spatial deviation of 0.106 mm.Qualitative verification was conducted through experimental validation of three distinct types.They confirmed the reliability of the proposed method,which allowed for accurate centroid measurements of various products without requiring positioning fixtures.This advancement significantly broadened the applicability and scope of centroid measurement devices,offering new theoretical insights and methodologies for the measurement of complex parts and systems.
基金Supported in part by NSFC(12071378,12461009),20XLB012,KJQN202100527,CSTB2022NSCQ-MSX0259 and KJQN202300557.
文摘In this paper,the Orlicz centroid function for log-concave functions is introduced.A rearrangement inequality of the Orlicz centroid function for log-concave functions is obtained.The rearrangement inequality implies the Orlicz Busemann-Petty centroid inequality of Lutwak,Yang and Zhang[23].
基金supported by National Natural Science Foundation of China-Youth Program(No.62303420)。
文摘The precise acquisition of the quality characteristic parameters of large aircraft directly affects its performance characteristics.For large aircrafts such as missiles and rockets with internal fillings,traditional measurement methods involving large-angle tilting or rotation may pose safety risks.In light of the characteristics of large aircraft and in combination with existing measurement methods,we design a mass and centroid measurement method based on four-point support and small-angle tilting,and develop a set of mass and centroid testing system.This method obtains the intersection point of the gravity action line in the product coordinate system through coordinate transformation in two postures,thereby obtaining the three-dimensional centroid of the aircraft.We first elaborate on the principle of this method in detail,then introduce the composition of the equipment,and analyze the structural stress of key components.Finally,experimental verification and uncertainty analysis are carried out.Experimental verification shows that the maximum deviation of the mass measurement accuracy is less than 0.02%,the centroid measurement accuracy in the X direction is±0.15 mm,in the Y direction it is±0.21 mm,and in the Z direction it is±0.19 mm.
基金supported in part by the National Natural Science Foundation of China under Grant 52575004the Beijing Natural Science Foundation under Grant L243004the National Natural Science Foundation of China under Grant 62403060.
文摘The problem of disturbance rejection in humanoid robots has been properly studied,with most prior work focusing on hip-ankle-stepping compliance control strategies or whole-body inverse dynamics control.This paper presents an adaptive disturbance rejection balance controller based on a Variable-inertia Centroidal Model Predictive Control(ViC-MPC)approach,designed to address both minor disturbances that affect standing balance and major disturbances requiring stepping adjustments.The controller also facilitates reliable balance recovery after stepping adjustments.The humanoid robot is modeled as a spatial variable-inertia ellipsoid,representing the distribution of centroidal dynamics,with the contact wrenches optimized in real-time through a customized MPC formulation.Inspired by capturability-based constraints,we propose an adaptive dynamic stability transition strategy.This strategy is activated based on the Retrospective Horizon Average Centroidal Velocity(RHACV)and the Capture Point(CP),ensuring effective stepping adjustments and disturbance rejection.With the torque-controlled humanoid robot BHR8P,extensive simulation and experimental results demonstrate the effectiveness of the proposed method,highlighting its capability to adapt to and recover from various disturbances with improved stability.
