rencheng zheng | Kochi University of Technology (original) (raw)
Papers by rencheng zheng
Journal of Physics: Conference Series, 2012
Potential applications for stochastic resonance have developed strongly in recent years. This pap... more Potential applications for stochastic resonance have developed strongly in recent years. This paper presents a study of an application of stochastic resonance in a mechanical system. Since a linear system cannot normally exhibit stochastic resonance, a cantilever beam with an end magnet was used to constitute a bistable nonlinear oscillator. Excited by ambient random vibration, the elastic beam undergoes a modulation of the potential well by means of a periodic excitation and flips between bistable states as a result of this. By adjusting the distance between the end magnet and a fixed magnet it is possible to drive the system controllably between bistable states. An electromagnet was used to provide the periodical parametric excitation which can result in stochastic resonance. The conditions for the occurrence of stochastic resonance are also discussed in the paper. Furthermore, simulations and experimental studies have been implemented to illustrate the application. The experimental results prove that stochastic resonance can occur, and that it can be usefully applied in such a mechanical system under specific conditions.
Journal of System Design and Dynamics, 2011
Physical Fatigue Comparison of Eco-Driving and Normal Driving
Journal of Biomechanical Science and Engineering, 2008
The kinetics analysis of ankle, knee and hip joints during gait is fundamental for rehabilitation... more The kinetics analysis of ankle, knee and hip joints during gait is fundamental for rehabilitation and clinical diagnosis but data are commonly obtained by means of the laboratory-restricted equipment such as a force plate and optical camera system, which usually require complicated computing programs and professional operation. In this study, we have developed a wearable sensor system to facilitate joint kinetics analysis to assess body movement in daily activities. The sensor system is composed of a shoe-based force sensor which measures ground reaction force (GRF) and center of pressure (CoP), and a leg-attached motion sensor consisting of three uniaxial gyroscopes units which detect lower limbs movement. This paper presents a kinetics analysis of ankle, knee and hip joints in the sagittal plane by using the sensor system on human normal level walking during whole gait phases. In order to estimate the joint kinetics, an inverse kinetics method based on the sensing signals and gait characteristics was developed. In the validation experiments with 10 subjects, joint kinetics was calculated using data synchronously measured by the sensor system and a force plate & optical camera system. The root mean square (RMS) differences of the ankle, knee and hip joints moments between the two systems in a gait cycle were (2 ± 0.34) (mean ± standard deviation) Nm, (7.2 ± 1.34) Nm and (11.2 ± 1.3) Nm, being (5.4 ± 0.7)%, (6 ± 0.32)% and (6.1 ± 0.25)% of the maximal magnitude of ankle, knee and hip joints moments respectively. The RMS differences of the ankle, knee and hip joints powers between the two systems in a gait cycle were (4.2 ± 0.4) W, (5.7 ± 2.1) W and (5.7 ± 0.3) W, being (8.4 ± 0.4)%, (4.1 ± 0.5)% and (6.4 ± 0.4)% of the maximal magnitude of joint powers respectively. The experimental results demonstrate the feasibility and effectiveness of the joint kinetics analysis using the wearable sensor system for a daily application in gait analysis.
Journal of Biomechanics, 2009
A new method using a double-sensor difference based algorithm for analyzing human segment rotatio... more A new method using a double-sensor difference based algorithm for analyzing human segment rotational angles in two directions for segmental orientation analysis in the three-dimensional (3D) space was presented. A wearable sensor system based only on triaxial accelerometers was developed to obtain the pitch and yaw angles of thigh segment with an accelerometer approximating translational acceleration of the hip joint and two accelerometers measuring the actual accelerations on the thigh. To evaluate the method, the system was first tested on a 2° of freedom mechanical arm assembled out of rigid segments and encoders. Then, to estimate the human segmental orientation, the wearable sensor system was tested on the thighs of eight volunteer subjects, who walked in a straight forward line in the work space of an optical motion analysis system at three self-selected speeds: slow, normal and fast. In the experiment, the subject was assumed to walk in a straight forward way with very little trunk sway, skin artifacts and no significant internal/external rotation of the leg. The root mean square (RMS) errors of the thigh segment orientation measurement were between 2.4° and 4.9° during normal gait that had a 45° flexion/extension range of motion. Measurement error was observed to increase with increasing walking speed probably because of the result of increased trunk sway, axial rotation and skin artifacts. The results show that, without integration and switching between different sensors, using only one kind of sensor, the wearable sensor system is suitable for ambulatory analysis of normal gait orientation of thigh and shank in two directions of the segment-fixed local coordinate system in 3D space. It can then be applied to assess spatio-temporal gait parameters and monitoring the gait function of patients in clinical settings.
This paper presents a study on quantitative dynamics analysis of human lower limb using developed... more This paper presents a study on quantitative dynamics analysis of human lower limb using developed wearable sensor systems that can measure reaction force and detect the following gait phases: initial contact, loading response, mid stance, terminal stance, pre-swing, initial swing, mid swing and terminal swing. Since conventional camera-based motion analysis system and reaction force plate system require costly devices, vast space as well as time-consuming calibration experiments, the wearable sensor-based system is much cheaper. Gyroscopes and two-axis accelerometers are incorporated in this wearable sensor system. The former are attached on the surface of the foot, shank and thigh to measure the angular velocity of each segment, and the latter are used to measure inclination of the attached leg segment (shank) in every single human motion cycle for recalibration. Ground reaction forces during human walking are synchronously measured using a wearable force sensor integrated in a shoes mechanism. Finally, experiment has been performed to compare the measurement results from the wearable sensor system with the data obtained from an optical motion analysis system and a force plate. The results showed that the measurement of human lower limb orientations and reaction forces for human dynamics analysis could be reliably implemented using the wearable sensor systems.
This paper presents a study on quantitative dynamics analysis of human lower limb using developed... more This paper presents a study on quantitative dynamics analysis of human lower limb using developed wearable sensor systems that can measure reaction force and detect the following gait phases: initial contact, loading response, mid stance, terminal stance, pre-swing, initial swing, mid swing and terminal swing. Since conventional camera-based motion analysis system and reaction force plate system require costly devices, vast space as well as time-consuming calibration experiments, the wearable sensor-based system is much cheaper. Gyroscopes and two-axis accelerometers are incorporated in this wearable sensor system. The former are attached on the surface of the foot, shank and thigh to measure the angular velocity of each segment, and the latter are used to measure inclination of the attached leg segment (shank) in every single human motion cycle for recalibration. Ground reaction forces during human walking are synchronously measured using a wearable force sensor integrated in a shoes mechanism. Finally, experiment has been performed to compare the measurement results from the wearable sensor system with the data obtained from an optical motion analysis system and a force plate. The results showed that the measurement of human lower limb orientations and reaction forces for human dynamics analysis could be reliably implemented using the wearable sensor systems.
In this research, the dynamic moment arm length of legpsilas muscle-tendon groups, including Sole... more In this research, the dynamic moment arm length of legpsilas muscle-tendon groups, including Soleus (SO), Tibilis Anterior (TA), Biceps Femoris Caput Breve (BS), Glusteus (GU), Vastus (VA), Iliopsoas (IL), Gastrocnemius (GA), Rectus Femoris (RF) and Hamstring (HA), was estimated in the sagittal plane based on a wearable sensor system. The wearable sensor system for body motion analysis in daily environment was used to measure kinematical data of lower extremities during gait instead of optical camera system that is laboratory-restricted. A serious of regression equations by inputting morphological parameters of lower extremities osteology was used to calculate a muscle-tendon origin-insertion coordinates in a coordinates system of musculoskeletal model. The morphological parameters of lower extremities osteology can be easily and directly measured by in vivo human body. By integration of the kinematical data and the musculoskeletal model, an algorithm was developed to estimate dynamic muscle-tendon moment arm length not only suitable for the simple articular muscles but also for the biarticular muscles. The result suggested the method in our study is feasible to estimate dynamic muscle-tendon moment arm length in human daily activities.
This paper presents a novel approach only based on triaxial accelerometers for three-dimensional ... more This paper presents a novel approach only based on triaxial accelerometers for three-dimensional (3D) orientation of lower limb segment during real-time motion. With two coaxially placed triaxial accelerometers, the actual resultant acceleration signals containing the acceleration of gravity and lineal movement along each axis were obtained. The angle displacements for orientation of each segment were calculated based on low-pass filtered accelerometer signals without integration. To evaluate accuracy, two calculated angular displacements around z, y axes during different rotational conditions were obtained and compared with the result from a high-accuracy camera system. Only based on one kind of inertial sensor, triaxial accelerometers, the approach can be used to assess spatio-temporal gait parameters and evaluate movements of each segment of the lower limbs, and thus to objectively monitor gait function of patients in a clinical setting.
Journal of Physics: Conference Series, 2012
Potential applications for stochastic resonance have developed strongly in recent years. This pap... more Potential applications for stochastic resonance have developed strongly in recent years. This paper presents a study of an application of stochastic resonance in a mechanical system. Since a linear system cannot normally exhibit stochastic resonance, a cantilever beam with an end magnet was used to constitute a bistable nonlinear oscillator. Excited by ambient random vibration, the elastic beam undergoes a modulation of the potential well by means of a periodic excitation and flips between bistable states as a result of this. By adjusting the distance between the end magnet and a fixed magnet it is possible to drive the system controllably between bistable states. An electromagnet was used to provide the periodical parametric excitation which can result in stochastic resonance. The conditions for the occurrence of stochastic resonance are also discussed in the paper. Furthermore, simulations and experimental studies have been implemented to illustrate the application. The experimental results prove that stochastic resonance can occur, and that it can be usefully applied in such a mechanical system under specific conditions.
Journal of System Design and Dynamics, 2011
Physical Fatigue Comparison of Eco-Driving and Normal Driving
Journal of Biomechanical Science and Engineering, 2008
The kinetics analysis of ankle, knee and hip joints during gait is fundamental for rehabilitation... more The kinetics analysis of ankle, knee and hip joints during gait is fundamental for rehabilitation and clinical diagnosis but data are commonly obtained by means of the laboratory-restricted equipment such as a force plate and optical camera system, which usually require complicated computing programs and professional operation. In this study, we have developed a wearable sensor system to facilitate joint kinetics analysis to assess body movement in daily activities. The sensor system is composed of a shoe-based force sensor which measures ground reaction force (GRF) and center of pressure (CoP), and a leg-attached motion sensor consisting of three uniaxial gyroscopes units which detect lower limbs movement. This paper presents a kinetics analysis of ankle, knee and hip joints in the sagittal plane by using the sensor system on human normal level walking during whole gait phases. In order to estimate the joint kinetics, an inverse kinetics method based on the sensing signals and gait characteristics was developed. In the validation experiments with 10 subjects, joint kinetics was calculated using data synchronously measured by the sensor system and a force plate & optical camera system. The root mean square (RMS) differences of the ankle, knee and hip joints moments between the two systems in a gait cycle were (2 ± 0.34) (mean ± standard deviation) Nm, (7.2 ± 1.34) Nm and (11.2 ± 1.3) Nm, being (5.4 ± 0.7)%, (6 ± 0.32)% and (6.1 ± 0.25)% of the maximal magnitude of ankle, knee and hip joints moments respectively. The RMS differences of the ankle, knee and hip joints powers between the two systems in a gait cycle were (4.2 ± 0.4) W, (5.7 ± 2.1) W and (5.7 ± 0.3) W, being (8.4 ± 0.4)%, (4.1 ± 0.5)% and (6.4 ± 0.4)% of the maximal magnitude of joint powers respectively. The experimental results demonstrate the feasibility and effectiveness of the joint kinetics analysis using the wearable sensor system for a daily application in gait analysis.
Journal of Biomechanics, 2009
A new method using a double-sensor difference based algorithm for analyzing human segment rotatio... more A new method using a double-sensor difference based algorithm for analyzing human segment rotational angles in two directions for segmental orientation analysis in the three-dimensional (3D) space was presented. A wearable sensor system based only on triaxial accelerometers was developed to obtain the pitch and yaw angles of thigh segment with an accelerometer approximating translational acceleration of the hip joint and two accelerometers measuring the actual accelerations on the thigh. To evaluate the method, the system was first tested on a 2° of freedom mechanical arm assembled out of rigid segments and encoders. Then, to estimate the human segmental orientation, the wearable sensor system was tested on the thighs of eight volunteer subjects, who walked in a straight forward line in the work space of an optical motion analysis system at three self-selected speeds: slow, normal and fast. In the experiment, the subject was assumed to walk in a straight forward way with very little trunk sway, skin artifacts and no significant internal/external rotation of the leg. The root mean square (RMS) errors of the thigh segment orientation measurement were between 2.4° and 4.9° during normal gait that had a 45° flexion/extension range of motion. Measurement error was observed to increase with increasing walking speed probably because of the result of increased trunk sway, axial rotation and skin artifacts. The results show that, without integration and switching between different sensors, using only one kind of sensor, the wearable sensor system is suitable for ambulatory analysis of normal gait orientation of thigh and shank in two directions of the segment-fixed local coordinate system in 3D space. It can then be applied to assess spatio-temporal gait parameters and monitoring the gait function of patients in clinical settings.
This paper presents a study on quantitative dynamics analysis of human lower limb using developed... more This paper presents a study on quantitative dynamics analysis of human lower limb using developed wearable sensor systems that can measure reaction force and detect the following gait phases: initial contact, loading response, mid stance, terminal stance, pre-swing, initial swing, mid swing and terminal swing. Since conventional camera-based motion analysis system and reaction force plate system require costly devices, vast space as well as time-consuming calibration experiments, the wearable sensor-based system is much cheaper. Gyroscopes and two-axis accelerometers are incorporated in this wearable sensor system. The former are attached on the surface of the foot, shank and thigh to measure the angular velocity of each segment, and the latter are used to measure inclination of the attached leg segment (shank) in every single human motion cycle for recalibration. Ground reaction forces during human walking are synchronously measured using a wearable force sensor integrated in a shoes mechanism. Finally, experiment has been performed to compare the measurement results from the wearable sensor system with the data obtained from an optical motion analysis system and a force plate. The results showed that the measurement of human lower limb orientations and reaction forces for human dynamics analysis could be reliably implemented using the wearable sensor systems.
This paper presents a study on quantitative dynamics analysis of human lower limb using developed... more This paper presents a study on quantitative dynamics analysis of human lower limb using developed wearable sensor systems that can measure reaction force and detect the following gait phases: initial contact, loading response, mid stance, terminal stance, pre-swing, initial swing, mid swing and terminal swing. Since conventional camera-based motion analysis system and reaction force plate system require costly devices, vast space as well as time-consuming calibration experiments, the wearable sensor-based system is much cheaper. Gyroscopes and two-axis accelerometers are incorporated in this wearable sensor system. The former are attached on the surface of the foot, shank and thigh to measure the angular velocity of each segment, and the latter are used to measure inclination of the attached leg segment (shank) in every single human motion cycle for recalibration. Ground reaction forces during human walking are synchronously measured using a wearable force sensor integrated in a shoes mechanism. Finally, experiment has been performed to compare the measurement results from the wearable sensor system with the data obtained from an optical motion analysis system and a force plate. The results showed that the measurement of human lower limb orientations and reaction forces for human dynamics analysis could be reliably implemented using the wearable sensor systems.
In this research, the dynamic moment arm length of legpsilas muscle-tendon groups, including Sole... more In this research, the dynamic moment arm length of legpsilas muscle-tendon groups, including Soleus (SO), Tibilis Anterior (TA), Biceps Femoris Caput Breve (BS), Glusteus (GU), Vastus (VA), Iliopsoas (IL), Gastrocnemius (GA), Rectus Femoris (RF) and Hamstring (HA), was estimated in the sagittal plane based on a wearable sensor system. The wearable sensor system for body motion analysis in daily environment was used to measure kinematical data of lower extremities during gait instead of optical camera system that is laboratory-restricted. A serious of regression equations by inputting morphological parameters of lower extremities osteology was used to calculate a muscle-tendon origin-insertion coordinates in a coordinates system of musculoskeletal model. The morphological parameters of lower extremities osteology can be easily and directly measured by in vivo human body. By integration of the kinematical data and the musculoskeletal model, an algorithm was developed to estimate dynamic muscle-tendon moment arm length not only suitable for the simple articular muscles but also for the biarticular muscles. The result suggested the method in our study is feasible to estimate dynamic muscle-tendon moment arm length in human daily activities.
This paper presents a novel approach only based on triaxial accelerometers for three-dimensional ... more This paper presents a novel approach only based on triaxial accelerometers for three-dimensional (3D) orientation of lower limb segment during real-time motion. With two coaxially placed triaxial accelerometers, the actual resultant acceleration signals containing the acceleration of gravity and lineal movement along each axis were obtained. The angle displacements for orientation of each segment were calculated based on low-pass filtered accelerometer signals without integration. To evaluate accuracy, two calculated angular displacements around z, y axes during different rotational conditions were obtained and compared with the result from a high-accuracy camera system. Only based on one kind of inertial sensor, triaxial accelerometers, the approach can be used to assess spatio-temporal gait parameters and evaluate movements of each segment of the lower limbs, and thus to objectively monitor gait function of patients in a clinical setting.