Active Seat Research Articles

Neural networks-based adaptive dynamic surface control for vehicle active suspension systems with time-varying displacement constraints

This paper addresses controlling of displacements of vehicle active suspension systems with an active seat suspension and a human-body model. A neural networks-based dynamic surface control strategy is constructed for the active suspension systems. Specifically, asymmetric time-varying barrier Lyapunov functions are applied to ensure that the displacements of vehicle active suspensions do not violate their time-varying constraint bounds. Neural networks are used to approximate unknown functions in the active suspension systems and their basis function properties are employed to deal with functions with non-strict form. Dynamic surface control technique is used to reduce the complexity of the controller. Advantages of the control strategy are substantiated by two simulation examples.

Active Control of Uncertain Seat Suspension System Based on a State and Disturbance Observer

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.

A Systematic Literature Review of Various Control Techniques for Active Seat Suspension Systems

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.

A comparison of anti-whiplash seats during low/moderate speed rear-end collisions

Objectives: The Insurance Institute for Highway Safety (IIHS) rates automotive seats as good, acceptable, marginal, and poor on their abilities to prevent whiplash injuries during rear-end collisions. The goal of this study was to compare the performance of some good- and poor-rated seats at speed changes below 16 km/h where some whiplash injuries occur.Methods: A BioRID II anthropometric test device (ATD) underwent rear-end collisions from 2 to 14 km/h while seated on one of two Volvo Whiplash Prevention seats (WHIPS), a Saab Active Head Restraint seat (SAHR), or a General Motors High Retention seat (GMHR). The WHIPS and SAHR seats were rated good whereas the GMHR seat was rated poor by the IIHS. The ATD’s kinematics, kinetics and three neck injury criteria were evaluated across the range of collision severities.Results: Most of the head and torso kinematics, kinetics and injury criteria exhibited graded responses with increasing collision severities. Only head extension angle remained relatively similar across all speed changes. Differences between the good- and poor-rated seats were most apparent in the upper neck loads and moments, and head retraction for speed changes greater than 6 km/h.Conclusions: The relatively similar occupant responses across all seats could explain the marginal reductions in whiplash injury risk between good- and poor-rated seats in field studies. Further research into the design of anti-whiplash devices is required to better understand the link between occupant response and injury, and to better mitigate the risk of whiplash injuries during rear-end collisions.

Improvement of Ride Comfort on Unpaved Road Using Active Seat Suspension

Improvement of Ride Comfort on Unpaved Road Using Active Seat Suspension

Active seat suspension for ultra-compact vehicles: experimental consideration on vibration control system using feedback of acceleration

Active seat suspension for ultra-compact vehicles: experimental consideration on vibration control system using feedback of acceleration

Active Seat Suspension for Ultra-Compact Mobility

Active Seat Suspension for Ultra-Compact Mobility

Active Seat Suspension for Ultra-Compact Mobility (Analytic Consideration on Actuator for Vibration Control)

Active Seat Suspension for Ultra-Compact Mobility (Analytic Consideration on Actuator for Vibration Control)

Ride Comfort Control System of Active Seat Suspension by Using Psychological Measurement

Ride Comfort Control System of Active Seat Suspension by Using Psychological Measurement

Performance, Movement, Posture, and Perceived Discomfort in Active vs. Static Seating

Active seating designs may enable users to move more frequently, thereby decreasing physiological risks associated with a sedentary lifestyle. In this preliminary study, two active seating designs (QOR360, Ariel; QOR360, Newton) were compared to a static chair (Herman Miller, Aeron) to understand how active vs. static seating may affect task performance, movement, posture, and perceived discomfort. This within-subjects experiment involved n = 11 student participants who sat upon each of the three chairs for 20 minutes while performing a series of computer-based tasks. Participants showed increased trunk movement while also reporting higher levels of perceived discomfort in the two active chair conditions. There was no significant difference in either posture or fine motor task performance between the active and static conditions. Future research may benefit from additional physiological measurements along with a wider variety of tasks that require seated users to make postural adjustments.

Upgrading seat suspension of tractor Belarus 1221

Ways to reduce vibrations at the tractor operator’s workplace in the unit with a trailer by improving the design of the suspension cushioning system are considered. Analysis of existing types of suspension systems shows that the most effective, in terms of reducing vibration loading, are active and semi-active systems. To reduce the vibration level at the tractor operator’s workplace in an aggregate with a trailer, an active seat suspension design has been developed. It includes a system of sensors and actuators that allow the current stiffness and damping of structural elements to be highly efficient in controlling the tractor operator’s workplace. To assess the effective use of the developed design, and compare it with the efficiency of the serial seat suspension, road tests were carried out. The tractor-transport unit in the tractor Belarus-1221 and the trailer 2PTS-4.5 with the serial and experienced suspension design were chosen as the object of research. During the field tests, the acceleration values were determined for the operator’s seat, the cab floor, the front and rear axles of the tractor. The test results showed that the developed technical solution allows reducing the vibration acceleration levels by 12-18% in comparison with the serial design.

A Review of Low-Frequency Active Vibration Control of Seat Suspension Systems

As a major device for reducing vibration and protecting passengers, the low-frequency vibration control performance of commercial vehicle seating systems has become an attractive research topic in recent years. This article reviews the recent developments in active seat suspensions for vehicles. The features of active seat suspension actuators and the related control algorithms are described and discussed in detail. In addition, the vibration control and reduction performance of active seat suspension systems are also reviewed. The article also discusses the prospects of the application of machine learning, including artificial neural network (ANN) control algorithms, in the development of active seat suspension systems for vibration control.

1D1-4 Ride comfort control system using psychophysiological measurement (Experimental consideration using active seat suspension)

1D1-4 Ride comfort control system using psychophysiological measurement (Experimental consideration using active seat suspension)

Development of a multiaxis active seat mount to mitigate helicopter aircrew whole-body vibration exposure

This article presents the development and evaluation of a proof-of-concept multiaxis and actively controlled helicopter seat mount for aircrew whole-body vibration reduction. The multiaxis seat mount is designed to be installed between the helicopter seat floor and the seat supporting structure to minimize the impact on crashworthiness requirements of the helicopter seat. The design involves multiple miniature force actuators to counteract the vibrations of the seat frame and occupant transmitted from the helicopter floor in three orthogonal directions. The actuators are controlled by an adaptive feedforward filtered-x least mean square algorithm to cancel the helicopter floor vibration input. The prototype active seat mount design was tested in various configurations with a shaker table providing representative Bell-412 helicopter vibration inputs. Test results demonstrated that the vibrations of the seat frame and mannequin occupant body were suppressed simultaneously, and the major N/rev harmonic peaks of the occupant’s whole-body vibration were reduced by more than 20 dB. This demonstrated that the multiaxis active seat mount design can mitigate the whole-body vibration exposure of the helicopter aircrew to improve their ride quality and reduce adverse health effect.

Active Seat for Ultra-Compact Mobility with Voice Coil Motor (Fundamental Consideration on Design Method of Motors Considering Control of Vibration)

Active Seat for Ultra-Compact Mobility with Voice Coil Motor (Fundamental Consideration on Design Method of Motors Considering Control of Vibration)

Active Seat Suspension for Ultra-Compact Mobility

Active Seat Suspension for Ultra-Compact Mobility

Active Seat Suspension for Ultra-Compact Mobility

Active Seat Suspension for Ultra-Compact Mobility

Control of a multiple-DOF vehicle seat suspension with roll and vertical vibration

In this paper, the control of roll vibration and vertical vibration of a seat suspension caused by uneven road under both sides of tyres is studied. The heavy duty vehicles are generally working under severe conditions, where the uneven road can cause roll vibration and vertical vibration of the vehicle body and can have an effect on seat suspension. The conventional single-degree of freedom (single-DOF) seat suspension can only isolate the vertical vibration while the roll vibration will be totally transferred to the driver's body. The high magnitude of driver body's lateral acceleration caused by roll vibration will influence drivers' health and have a negative effect on ride comfort. A two-layer multiple-DOF active seat suspension, which has a z-axis DOF in the bottom layer and a roll DOF in the top layer, is proposed in this paper. A non-singular terminal sliding controller is designed to control the top-layer to reduce the lateral acceleration and roll acceleration by tracking a desired roll angle. An H∞ controller with disturbance compensation is applied to control the bottom-layer for vertical vibration isolation. Both controllers use the variables which can be measured or estimated in the practical application as feedback signals. Two inertial measurement units (IMUs) MPU9250 are used in order to estimate the rotary angles of the top and base platforms of the two-layer multiple-DOF active seat suspension. The effectiveness of the seat suspension and control method is validated by both simulations and experiments. A single-DOF active seat suspension and a well-tuned conventional passive one are applied for comparison. Based on ISO 2631, the vibration total value of frequency weighted root mean square (FW-RMS) acceleration of the multiple-DOF active seat surface has 29.8% and 23.6% reductions for evaluating its influence on health and ride comfort, respectively, when compared with the single-DOF active one. The proposed vibration isolation method can effectively reduce the whole body vibration (WBV) of heavy duty vehicle drivers, and it shows high potential for practical application.

Experimental Assessment of a Controlled Slippage Magnetorheological Actuator for Active Seat Suspensions

Passive air springs are the golden standard in heavy vehicle seat suspensions, as they provide economical means to isolate drivers from road disturbances. They are nevertheless likely to expose drivers to vibration levels higher than recommended by the ISO-2631-1 standard over a typical 8-h shift. Although existing commercial active seat suspensions have proven their superiority over passive suspensions, practical limitations such as cost or lack of overall dynamic performance have slowed down their widespread adoption. Controlled slippage magnetorheological (MR) actuators are a promising alternative because they offer a dynamic performance similar to direct-drive motors in a packaging and cost similar to economical geared motors. This paper is the first to experimentally assess the overall closed-loop performance of an active seat suspension powered by a controlled slippage MR actuator including vibration attenuation, power consumption, and seat travel. Unlike semiactive MR actuators such as MR dampers that have been extensively studied, controlled slippage MR actuators are fully active and offer a significantly better performance for rough road conditions. The active seat was tested in a laboratory on a vibrating platform recreating the floor acceleration profile of a dump truck rolling on a quarry road. The seat was also tested on an actual highway truck rolling on a roadway. Results show that with a linear–quadratic–Gaussian controller, the proposed active suspension effectively reduces floor vibrations by a factor of 2–3, while using an average power consumption of 86 W and having an average relative travel range of 1–10 mm root mean square. These results fall in line with commercially available active seat suspensions.

Ride Comfort Control System Considering Physiological and Psychological Characteristics: Effect of Masking on Vertical Vibration on Passengers

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.