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In this work, we present a study on seat suspension technology that integrates pneumatic muscles, marking a significant advancement in active vibration control. This innovative approach addresses the limitations of traditional suspension systems, providing enhanced comfort and adaptability. A key achievement is the development of a mathematical model for controlling horizontal seat vibration, which serves as a valuable design tool for evaluating seat suspension under various conditions and control strategies. The creation of a custom microcontroller, benchmarked against a standard from National Instruments, highlights the practical applications of this research. Positive results suggest a promising future for this technology in industrial settings, where vibration reduction is critical. The system's scalability and user-adjustable signal levels further enhance its potential for widespread industrial adoption. [ABSTRACT FROM AUTHOR]

Aiming at the system non-linearity caused by the change of load mass of seat suspension and the effective control of seat vibration, an active control system of variable mass seat suspension based on the proportional-derivative (PD) control was proposed. The proposed control system structure was based on several different controllers. The primary controller was used to evaluate the actual value of the main force that should be generated in the suspension system, and the secondary controller was used to calculate the instantaneous value of the signal that controled the active element through its reverse model. The active seat suspension system model was established, and the active seat suspension control system was designed. The robustness of seat suspension system with different load mass was verified by simulation. The controller parameters were optimized to realize the fine control of adaptive quality identification of active seat suspension. The optimized design results were compared and verifed, and the results show that the influence of mass change on the dynamic performance of active seat suspension system is significantly reduced. Under 100 kg mass load and EM3、 EM5 and EM6 excitation signals, the SEAT factor of the active system is reduced respectively by 49.81%, 20.96% and 29.85%. At the same time, the suspension stroke is reduced respectively by 4.76%, 33.87% and 18.18%. The active control system established in this paper significantly improves the performance of the seat suspension, and has better robustness to the varying load mass, which provides a reference for the research on the vibration isolation performance of the active seat suspension.

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this article, a linear quadratic regulator (LQR)-based sliding model control strategy was proposed for the commercial vehicle seat suspension system. First, the multiple degrees of freedom mechanical dynamics model of a quarter suspension system was built. Then, the LQR force command planner was designed based on mechanical dynamics to ensure driver comfort. Second, considering the mechanical dynamics augmented with hydraulic actuator dynamics, a proportional-integral sliding mode control strategy was developed to track the reference force, which was calculated by the LQR force command planner in real time. Taking the problems of noise disturbances and unavailable full states feedback into consideration, the Kalman filter and tracking differentiator were designed and integrated into the control algorithm. Finally, the quarter suspension AMESim model was built, and the proposed control strategy was implemented and verified in the AMESim-Matlab/Simulink co-simulation environment. Comprehensive simulations were carried out. The simulation results, both from time domain and frequency domain perspective, indicated that the seat ride comfort can be effectively improved with the proposed method. [ABSTRACT FROM AUTHOR]

In this work, we present a study on seat suspension technology that integrates pneumatic muscles, marking a significant advancement in active vibration control. This innovative approach addresses the limitations of traditional suspension systems, providing enhanced comfort and adaptability. A key achievement is the development of a mathematical model for controlling horizontal seat vibration, which serves as a valuable design tool for evaluating seat suspension under various conditions and control strategies. The creation of a custom microcontroller, benchmarked against a standard from National Instruments, highlights the practical applications of this research. Positive results suggest a promising future for this technology in industrial settings, where vibration reduction is critical. The system’s scalability and user-adjustable signal levels further enhance its potential for widespread industrial adoption.

This paper aims to optimize a fuzzy logic controller (FLC) active seat suspension applied to an articulated truck semi-trailer seat to improve ride comfort considering the energy consumption of the controller. The proposed truck model is a linear truck with 13 degree-of-freedom (DOF). Two objective functions are defined seat root mean square (RMS) acceleration related to ride comfort and controller RMS force pertaining to the energy consumption of the controller. The Pareto Front is obtained for these two objective functions using the multi-objective optimization method in MATLAB. The optimization is based on the Non-Dominated Sorting Genetic Algorithm (NSGA-II), which has been proposed as a powerful decision space exploration engine based on a genetic algorithm (GA) for solving a multi-objective function problem. Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), which is simple and effective, selects a set of optimal controller parameters. In addition, considering the changes of effective parameters in the truck, including trailer load and location, tyres' stiffness and the driver's mass, has been investigated to provide Monte Carlo sensitivity analysis of these parameters on objective functions. Finally, using ISO 2631-1, the ride comfort and controller required force levels before and after optimization are compared. The results of this optimization indicate a significant improvement in ride comfort and controller force which has been different in various conditions of truck speed and road classes. The results have shown that the maximum amount of improvement in ride comfort is about 25% which happens on Class-C road (at the truck speed of 60 km/h), and the control force reduction peaks at around 60%, which occurs on Class-A road (at the truck speed of 60 km/h). The simulation is validated by MSC-ADAMS software. [ABSTRACT FROM AUTHOR]

In order to reduce the influence of ground vibration generated by tractors during driving and operation on driving stability and driver ’s ride comfort, this paper proposes a tractor active seat suspension control method based on model predictive control (MPC). Through the establishment of three degrees of freedom tractor active seat suspension model, electromagnetic actuator (linear motor) model and ground excitation input model, the inner and outer loop control strategy of linear motor active seat suspension based on outer loop MPC control and inner loop current hysteresis comparison control is proposed. The influence of MPC parameters on the vibration performance and control cost of seat suspension is compared and analyzed through experiments. The appropriate system parameters are selected through optimization analysis. The simulation and experimental results show that compared with the passive seat suspension and PID seat suspension, the tractor active seat suspension based on model predictive control improves the ride comfort and vibration reduction characteristics of the tractor, and on this basis, it reduces the energy consumption required for the seat suspension system to achieve active control, while ensuring the timeliness of MPC control.

The deterioration of ride comfort in ultra-compact vehicles has recently become an increasing concern. Active seat suspension was proposed to improve the ride comfort of ultra-compact vehicles. An active seat suspension is a vibration control device that is easily installed. The general vibration control system of the active seat suspension is fed back to the displacement and velocity by integrating the measured seat acceleration. This control has problems, such as control delay and deviation by integration. In this study, we focused on vibration control using acceleration directly. First, we established a control model that feeds back the acceleration to terminate the error occurring in the integral process and investigated the change in vibration characteristics in the case where the feedback gain of acceleration was changed. Second, the control system was analyzed to investigate the performance of the control based on the frequency characteristics. As a result, it was confirmed that the frequency response changes when the feedback gain is changed. In acceleration feedback control, ride comfort was improved by selecting a proper feedback gain because the characteristics of frequency were changed by the gain.

To reduce seat vibration caused by uneven road surfaces, the time-delay feedback control into the seat suspension system was introduced and an active seat suspension control method based on time-delay feedback was proposed in this paper. A three-degree-of-freedom (3-DOF) suspension model with time-delay feedback control was established. The time-delay independent stability region and critical stability curve of the system were derived using the method of characteristic root and stability switching. The effect of feedback control parameters on system vibration was investigated in the stability region. The seat acceleration (SA), body acceleration (BA), suspension dynamic deflection (SDD), and tire dynamic displacement (TDD) were used as multi-objective optimization functions and the optimal values of feedback control parameters were obtained based on the particle swarm algorithm (PSO) with above optimization functions. The numerical simulation was conducted to validate the proposed model. The simulated results show that the time-delay feedback control can significantly suppress the vibration response of the seat and effectively improve the suspension performance under different road excitation compared with the passive suspension. It can be seen that the active seat suspension with time-delay control significantly improve ride comfort and handling stability of the vehicle, which can be used as a reference for the active control technology of vehicle suspension. [ABSTRACT FROM AUTHOR]

Vehicle seats have a significant impact on the comfort of passengers. The development of seats is a field in which scholars are widely concerned. In this study, we add an electromagnetic levitation structure and design a new active seat suspension based on the passive seat suspension. Then, simulation research is carried out based on a C-level road surface combined with integral sliding mode control and state feedback control. The results show that both state feedback control and integral sliding mode control positively affect vehicle seat vibration reduction, and integral sliding mode control has a better anti-interference effect than state feedback control. At the same time, it is proved that the seat suspension has good working characteristics and economy. [ABSTRACT FROM AUTHOR]

We investigated whether there is a correlation between the comfort felt by occupants and the comfort estimated from biological information obtained by experiments to improve the ride quality of an ultra-compact vehicle. A single frequency in the vertical direction can help to estimate occupant comfort. However, we hypothesized that the study of a single frequency was insufficient. We oscillated the occupants with vibrations containing multiple vibration frequencies and obtained biometric information. The vibration frequency was set based on the difference in ride quality felt by humans. Biometric information was obtained using a cerebral hemodynamic meter and electrocardiogram. Acquiring multiple types of biometric information helps to more accurately estimate the psychological state. After the experiment, we obtained a subjective evaluation of comfort against vibrations using the visual analog scale (VAS). The biometric information obtained by the experiment was cluster-analyzed, and experimental participants with similar characteristics of the biometric information were grouped. Multiple regression analysis was performed based on the values of the typical biometric information of the cluster. Comfort was estimated from biometric information using multiple regression analysis. A correlation was confirmed between measured and estimated VAS scores. [ABSTRACT FROM AUTHOR]

The combination of dynamic vibration absorber and partial state feedback with time-delay is called delayed resonator. In order to suppress the seat vibration caused by uneven road surface and improve ride comfort, the delayed resonator is applied to the seat suspension to realize active control of the seat suspension system. The dynamic model of the half-vehicle suspension system is established, and the time-delay differential equation of the system under external excitation is solved by the precise integration method. The root mean square of the time-domain vibration response of seat displacement, seat acceleration and vehicle acceleration are selected as the objective function. Then, the optimal time-delay control parameters are obtained by particle swarm optimization algorithm. The frequency sweeping method is used to obtain the critical time-delay value and time-delay stable interval of the system. Finally, an active seat suspension model with delayed resonator is established for numerical simulation. The results show that the delayed resonator can greatly suppress the seat vibration response regardless of the road simple harmonic excitation or random excitation. Compared with dynamic vibration absorber, it has a better vibration absorption effect and a wider vibration reduction frequency band. [ABSTRACT FROM AUTHOR]

We investigated whether there is a correlation between the comfort felt by occupants and the comfort estimated from biological information obtained by experiments to improve the ride quality of an ultra-compact vehicle. A single frequency in the vertical direction can help to estimate occupant comfort. However, we hypothesized that the study of a single frequency was insufficient. We oscillated the occupants with vibrations containing multiple vibration frequencies and obtained biometric information. The vibration frequency was set based on the difference in ride quality felt by humans. Biometric information was obtained using a cerebral hemodynamic meter and electrocardiogram. Acquiring multiple types of biometric information helps to more accurately estimate the psychological state. After the experiment, we obtained a subjective evaluation of comfort against vibrations using the visual analog scale (VAS). The biometric information obtained by the experiment was cluster-analyzed, and experimental participants with similar characteristics of the biometric information were grouped. Multiple regression analysis was performed based on the values of the typical biometric information of the cluster. Comfort was estimated from biometric information using multiple regression analysis. A correlation was confirmed between measured and estimated VAS scores.

In this work, the dedicated test stand was applied to investigate the human body–vehicle seat system. The particular signals were measured by accelerometers placed on the seat and the human head. The horizontal vibrations were applied as the input to the system. As an alternative to the classical Fourier approach, the wavelet transfer function was introduced to describe the effectiveness of particular seat suspension. The human head reaction was investigated as the system output. [ABSTRACT FROM AUTHOR]

To obtain the static shape of the continuous steel plate and vibration characteristic, we performed the analysis of the multi-body dynamics in which the continuous steel plate was discretized in many solid bodies. The shape of the steel plate obtained by the measurement experiment was agreement with the static shape of the steel plate obtained by the analysis. Then, dynamical analysis was performed when white noise input to the steel plate. It was confirmed that the vibration could be suppressed when the electromagnets were installed in consideration of the static shape of the steel plate. [ABSTRACT FROM AUTHOR]

In the current automobile industry, the demand for ultra-compact vehicles as a means of transportation for elderly people and other travelers, has been increasing. The effect of vibration on the ride comfort of these vehicles is significant because of their small size and low weight. The vibration will increase the discomfort perceived by persons in the vehicle. Therefore, it is necessary to develop a vibration control system for safe and comfortable driving. To improve ride comfort, this research group proposed an active seat suspension using a voice coil motor at the seat section of the vehicle. In this study, the influence of jerk on the psychological state, which was obtained from bioinstrumentation, was investigated. [ABSTRACT FROM AUTHOR]

In this paper, an active seat suspension system that is robust to uncertainties and unknown road profiles is designed using a state and disturbance observer. The controller which needs the measurement of just the seat frame position is analyzed with a 4-degree-of-freedom biodynamic model of the passenger for performance and stability. The proposed scheme is validated by simulation for a variety of road profiles under various uncertainties and compared with passive suspension, linear quadratic regulator-based active seat suspension, and conventional active cabin suspension using the evaluation norms set by ISO-2631. The proposed scheme is seen to be robust to uncertainties in seat frame suspension, passenger mass, and cabin suspension. [ABSTRACT FROM AUTHOR]

Drivers of heavy trucks are exposed to large amounts of vibration which can lead to serious health risks. Many suspension systems/methods can be used to isolate these transmitted vibrations, such as vehicle suspension systems, cabin suspension systems and seating suspension systems. The central idea of the work is to identify the research gaps and raise our future research questions in this specific area. The novelty of this paper is proposing a model predictive controller for active vibration control of seating suspension systems. A systematic literature review of the existing work of the vibration control of seating suspension systems has been conducted. Various control techniques that are used in the seating suspension systems have been summarized and evaluated. This paper focusses on the biodynamic model of the driver and seat for the first step needed in the design of the seating suspension system. Then, it illustrates the different types of the system vibration controls and their performance evaluation methods. At the end, the paper details several active seating suspension systems including their actuation system structures and control algorithms which are used in the heavy vehicle trucks. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the fuzzy control theory and optimal control theory， an integrated variable gain LQR(linear quadratic regulator)control method based on fuzzy control for vehicle active suspension and seat active suspension is proposed. Based on the establishment of "car-chair" three-degree-of-freedom dynamics model， taking the vertical acceleration of vehicle body and seat vertical acceleration as the control target and the dynamic displacement of the wheel and the range of vehicle suspension motion less than the specified value as the constraint conditions， the vehicle suspension and seat suspension variable gain LQR controller is designed， and the simulation experiment analysis and the comparison with Matlab/Simulink are carried out， whose results indicate that this control method has better control effect on seat suspension and vehicle suspension， and the validity and feasibility of the integrated variable gain LQR control method are verified， which could provide a reference for the future research of suspension system control. [ABSTRACT FROM AUTHOR]

Bioinstrumentation has been used in the automotive industry to evaluate the ride comfort level of different vehicles. However, there have been no studies attempting to incorporate bioinstrumentation in the controls. In this paper, we propose a ride comfort control system using the psychological state of the driver as estimated through bioinstrumentation. To evaluate the psychological state of the driver, we use the driver's heart rate variability, which allows us to calculate the R-R interval and the LF/HF, the values of which reflect the activities of the autonomic nervous system. In this paper, we investigated the usefulness of a ride comfort control system using adequate bioinstrumentation and switching criterions for the system. As the results indicate, the drivers become relaxed when using the ride comfort control system as based on their psychological state. Moreover, the drivers become more relaxed when using LF/HF as the switching criterion for ride comfort. [ABSTRACT FROM AUTHOR]

In the following paper, the dynamic modeling of a horizontal seat suspension which uses pneumatic muscles for the purpose of active vibration control is discussed. An original control system structure is proposed in order to improve the vibro-isolation properties of a horizontal seat suspension system. The presented control system design is based on inverse models of the pneumatic muscles and the primary controller that calculates the desired active force. By using the configurable control algorithm developed in this paper, it is possible to achieve a significant reduction in vibrations transmitted into the human body with just a slight increasing of the suspension travel. The active seat shows improved performance over the passive system in the 1–10 Hz frequency range. The results presented in this paper are useful in selecting the horizontal vibration control system for improving the comfort of a drive. [ABSTRACT FROM AUTHOR]

This paper presents a novel, simple and reliable control strategy for an active seat suspension, intended for use in a vehicle, which attenuates the harmful low-frequency vertical vibration at the driver’s seat. An advantage of this strategy is that it uses measurable preview information from the vehicle suspension. The control force is calculated from this preview information and controller gains obtained by optimising an objective function using a genetic algorithm (GA) approach. The objective function optimises ride comfort in terms of the Seat Effective Amplitude Transmissibility factor, taking into account constraints on both the allowable seat suspension stroke and actuator force capacity. This new controller is evaluated using both simulation and experimental tests in both the frequency and time domains. The simulation model is based upon a linear quarter vehicle model and a single degree of freedom seat suspension. Experimental tests are performed using a multi-axis simulation table and an active seat suspension. Finally, the performance of the active seat suspension is analysed and compared to a passive system, demonstrating significant acceleration attenuation of more than 10 dB across a broad frequency range. Consequently, this has the potential to improve ride comfort and hence reduce the driver’s fatigue using a reliable and cost-effective control method. [ABSTRACT FROM AUTHOR]

Active seat suspensions can be used to reduce the harmful vertical vibration of a vehicle’s seat by applying an external force using a closed loop controller. Many of the controllers found in the literature are difficult to implement practically, because they are based on using unavailable or difficult and costly measurements. This paper presents both simulation and experimental studies of five novel, simple, and cost-effective control strategies to be used for an active seat suspension in order to improve ride comfort at low frequencies below 20 Hz. These strategies use available and measurable feedforward (preview) information states from the vehicle secondary suspension, as well as feedback states from the seat suspension, together with gains optimised to minimise the occupant vibration. The gains were optimised using a genetic algorithm (GA), with a fitness function based on the seat effective amplitude transmissibility (SEAT) factor. Constraints on the control force and the seat suspension stroke were also included in the optimisation algorithm. Simulation and laboratory experimental tests were carried out to assess the performance of the proposed controllers according to the ISO 2631-1 standard, in both the frequency and time domains with a range of different road profiles. The experimental tests were performed using a multi-axis simulation table (MAST) and a physical active seat suspension configured as a hardware-in-loop (HIL) simulation with a virtual linear quarter vehicle model (QvM). The results demonstrate that the proposed controllers substantially attenuate the vertical vibration at the driver’s seat compared with both a passive and a proportional-integral-derivative (PID) active seat suspension and thus improve ride comfort together with reducing vibration-linked health risks. Moreover, experimental results show that employing both feedforward information and feedback vehicle body and seat acceleration signals in the controller provides isolation performance gains of up to 19.5 dB over the human body sensitivity frequency range and improves the ride comfort in terms of the SEAT factor and the weighted root mean square (RMS) seat acceleration by at least 25% when compared with a passive system, irrespective of vehicle forward speed. [ABSTRACT FROM AUTHOR]

Drivers of heavy trucks are exposed to large amounts of vibration which can lead to serious health risks. Many suspension systems/methods can be used to isolate these transmitted vibrations, such as vehicle suspension systems, cabin suspension systems and seating suspension systems. The central idea of the work is to identify the research gaps and raise our future research questions in this specific area. The novelty of this paper is proposing a model predictive controller for active vibration control of seating suspension systems. A systematic literature review of the existing work of the vibration control of seating suspension systems has been conducted. Various control techniques that are used in the seating suspension systems have been summarized and evaluated. This paper focusses on the biodynamic model of the driver and seat for the first step needed in the design of the seating suspension system. Then, it illustrates the different types of the system vibration controls and their performance evaluation methods. At the end, the paper details several active seating suspension systems including their actuation system structures and control algorithms which are used in the heavy vehicle trucks.

In this paper, a disturbance observer based Takagi-Sugeno (TS) fuzzy controller is proposed for an active seat suspension; both simulations and experiments have been performed verifying the performance enhancement and stability of the proposed controller. The controller incorporates closed-loop feedback control using the measured acceleration of the seat and deflection of the suspension; these two variables can be easily measured in practical applications, thus allowing the proposed controller to be robust and adaptable. A disturbance observer that can estimate the disturbance caused by friction, model simplification, and controller output error has also been used to compensate a H ∞ state feedback controller. The TS fuzzy control method is applied to enhance the controller’s performance by considering the variation of driver’s weight during operation. The vibration of a heavy duty vehicle seat is largest in the frequency range between 2 Hz and 4 Hz, in the vertical direction; therefore, it is reasonable to focus on controlling low frequency vibration amplitudes and maintain the seat suspensions passivity at high frequency. Moreover, both the simulation and experimental results show that the active seat suspension with the proposed controller can effectively isolate unwanted vibration amplitudes below 4.5 Hz, when compared with a well-tuned passive seat suspension. The active controller has been further validated under bump and random road tests with both a 55 kg and a 70 kg loads. The bump road test demonstrated the controller has good transient response capabilities. The random road test result has been presented both in the time domain and the frequency domain. When with the above two loads, the controlled seat suspensions root-mean-square (RMS) accelerations were reduced by 45.5% and 49.5%, respectively, compared with a well-tuned passive seat suspension. The proposed active seat suspension controller has great potential and is very practical for application as it can significantly improve heavy duty driver’s ride comfort. [ABSTRACT FROM AUTHOR]

In this work, a disturbance observer and state observer based terminal sliding mode (TSM) controller with acceleration data fusion is proposed for the active control of a seat suspension. In practical applications, the driver's body and the friction forces are difficult to be accurately described with a mathematical model; for this reason, the proposed controller is designed based on a model simplified from a 6-degree-of-freedom (6-DOF) seat-driver model with nonlinear friction. The disturbance observer and state observer are designed together with Linear Matrix Inequality (LMI) method. For improving the observer's performance, a complementary filter is applied to fuse the estimation of the seat suspension velocity from the acceleration measurement and the state observer. The proposed controller is validated using simulations with various bump excitations applied, and the conventional state feedback TSM controller is implemented for comparison. The proposed controller is also implemented in a practical active seat suspension prototype, and a well-tuned commercial heavy duty vehicle seat suspension is applied for comparison. The power spectral density (PSD) value and ISO 2631–1 standard are used to evaluate the active seat suspension system's performance under random vibration. Both the simulation and the experimental results indicate that with the proposed controller, the vibration magnitude caused by a rough road can be greatly reduced, and the driver ride comfort is greatly improved. [ABSTRACT FROM AUTHOR]

Active seat suspension has been proposed to improve ride comfort for ultra-compact mobility. Regarding the ride comfort of passengers due to vertical vibration, the authors have confirmed from biometry measurements that reduction of the vibration acceleration does not always produce the best ride comfort for passengers. Therefore, heart rate variability that can quantitatively reflect stress is measured in real time, and a control method was proposed that feeds back to active suspension and confirms its effectiveness by fundamental verification. In this paper, we will confirm the influence of the vibration stress on the psychological state of the occupant by the masking method.

Active seat suspensions can be used to reduce the harmful vertical vibration of a vehicle’s seat by applying an external force using a closed loop controller. Many of the controllers found in the literature are difficult to implement practically, because they are based on using unavailable or difficult and costly measurements. This paper presents both simulation and experimental studies of five novel, simple, and cost-effective control strategies to be used for an active seat suspension in order to improve ride comfort at low frequencies below 20 Hz. These strategies use available and measurable feedforward (preview) information states from the vehicle secondary suspension, as well as feedback states from the seat suspension, together with gains optimised to minimise the occupant vibration. The gains were optimised using a genetic algorithm (GA), with a fitness function based on the seat effective amplitude transmissibility (SEAT) factor. Constraints on the control force and the seat suspension stroke were also included in the optimisation algorithm. Simulation and laboratory experimental tests were carried out to assess the performance of the proposed controllers according to the ISO 2631-1 standard, in both the frequency and time domains with a range of different road profiles. The experimental tests were performed using a multi-axis simulation table (MAST) and a physical active seat suspension configured as a hardware-in-loop (HIL) simulation with a virtual linear quarter vehicle model (QvM). The results demonstrate that the proposed controllers substantially attenuate the vertical vibration at the driver’s seat compared with both a passive and a proportional-integral-derivative (PID) active seat suspension and thus improve ride comfort together with reducing vibration-linked health risks. Moreover, experimental results show that employing both feedforward information and feedback vehicle body and seat acceleration signals in the controller provides isolation performance gains of up to 19.5 dB over the human body sensitivity frequency range and improves the ride comfort in terms of the SEAT factor and the weighted root mean square (RMS) seat acceleration by at least 25% when compared with a passive system, irrespective of vehicle forward speed.

In the current automobile industry, the demand for ultra-compact vehicles as a means of transportation within a local area for elderly people, for example, for shopping, has been increasing. The effect of vibration of such vehicles on ride comfort is significant because of their small size and light weight, and it increases the discomfort perceived by persons in the vehicle. Moreover, ultra-compact vehicles frequently travel over alleys and unpaved roads; therefore, the ride comfort of ultra-compact vehicles is expected to deteriorate because of bumps, rough roads, and small obstacles. To solve this problem, we have proposed active seat suspension that can be installed in ultra-compact electric vehicles. Thus far, we have examined the control performance of this system and its practicality in terms of ride comfort, with the aim of reducing the vibration acceleration of the seat surface. To improve the ride comfort of vehicles, in addition to reducing the vibration acceleration of the seat surface, it is also necessary to control the vibration on the basis of the ride comfort perceived by drivers such as to reflect the mood and mental state at the time. Most studies have not focused on the psychological and physiological effects of active seat suspension on the ride comfort of ultra-compact vehicles. In this study, we carried out an outdoor traveling experiment and examined the effect of vertical vibrations on ride comfort by evaluating physiological and psychological information.

This paper presents the design, fabrication and testing of an innovative active seat suspension system for heavy-duty vehicles. Rather than using conventional linear actuators, such as hydraulic cylinders or linear motors, which need to be well maintained and are always expensive when high force outputs are required, the proposed seat suspension system directly applies a rotary motor in order to provide the required active actuation, without changing the basic structure of the existing off-the-shelf seat suspension. A gear reducer is also applied to amplify the output torque of the motor so that a high output torque can be achieved using a low rated power motor. A static output feedback H1 controller with friction compensation is designed to actively reduce seat vibration. Experiments are carried out to test the fabricated suspension prototype. The experimental results show that this type of seat suspension can achieve greater ride comfort in the frequency range of 2-6 Hz than a passive seat suspension. The newly designed active seat suspension is much more cost effective and can be suitable for heavy-duty vehicles. [ABSTRACT FROM AUTHOR]

Nowadays, ultra-compact electric vehicles have been increasingly demanded under the influence of environmental problem and the aged society. The ultra-compact electric vehicles are possible to travel on poor condition roads, such as narrow and unpaved roads. Thus, the ride comfort of the vehicles is expected to deteriorate when the ultra-compact electric vehicles travel on such road. Then it is important to reduce vibration of the vehicle. To solve these problems, we suggest active seat suspension that can be installed in ultra-compact electric vehicles. In this paper, we focused on the electrooculogram when fall from the bump of roadway boundary. [ABSTRACT FROM AUTHOR]

Based on the integrated models of ‘vehicle-seat-people'， an integrated vehicle seat and suspension robust H∞ integrated control strategy was proposed by using linear matrix inequalities (LMI) technique. An H∞ state feedback controller of integrated vehicle seat and suspension was designed， with the PSD of vertical body acceleration chosen as the controlled outputs and the limits of dynamic suspension deflection， relative dynamic tire load， and integrated control force chosen as the constrained outputs. The MATLAB simulation was employed in the paper， and the simulation results confirm the feasibility and effectiveness. The analysis results provide a fundamental basis for the study of active control suspension system. [ABSTRACT FROM AUTHOR]

In recent years human-machine interaction attracts scientific community attention because of human quality and health issues. Driver seat should be designed so that it would ensure occupational health as well as increase work efficiency. The aim of this research is to maintain seat height at constant level with regard to chassis excitation at different levels of frequency and amplitude by means of new design of pneumatic actuation circuit. Sinusoidal function was used for base vibration since almost all of excitation functions can be derived from it. System response shows in low frequency/high amplitude and high frequency/low amplitude chassis vibration, transmissibility decreased about 60% and 40% compared to solid suspension respectively. [ABSTRACT FROM AUTHOR]

To improve riding comfort of driver's seat, we have proposed active suspension system for heavy duty truck. In this study, the control mechanism of the active seat suspension was designed for a small vehicle such as community car with using the optimal control method. The operability improvement for senior citizens, the vibration isolation for babies and the riding comfort improvement on the unpaved road can be expected. In order to examine the effectiveness of the system, experiments were performed. [ABSTRACT FROM AUTHOR]

Active seat suspension has been proposed to improve ride comfort for ultra-compact mobility. Regarding the ride comfort of passengers due to vertical vibration, the authors have confirmed from biometry measurements that reduction of the vibration acceleration does not always produce the best ride comfort for passengers. Therefore, heart rate variability that can quantitatively reflect stress is measured in real time, and a control method was proposed that feeds back to active suspension and confirms its effectiveness by fundamental verification. In this paper, we will confirm the influence of the vibration stress on the psychological state of the occupant by the masking method. [ABSTRACT FROM AUTHOR]