Kazushi Sanada

Design of Clutch-Slip Controller for Automatic Transmission Using Backstepping

To improve the shift quality of vehicles with clutch-to-clutch gearshifts, a nonlinear controller using backstepping technique is designed for the clutch-slip control. Model uncertainties including steady-state errors and unmodeled dynamics are also considered as additive disturbance inputs, and the controller is designed such that the error dynamics is input-to-state stable. Lookup tables, which are widely used to represent complex nonlinear characteristics of engine systems, appear in their original form in the designed nonlinear controller. Finally, the designed controller is tested on an AMESim power train simulation model. Comparisons with an existing linear algorithm are given as well.

A Reduced-Order Nonlinear Clutch Pressure Observer for Automatic Transmission

For a novel type of automatic transmissions adopting clutch-to-clutch shift control technology with electro-hydraulic actuators, a clutch pressure observer method based on input-to-state stability (ISS) is proposed. Model uncertainties including steady state error and unmodelled dynamics are considered as additional disturbance inputs and the observer is designed in order that the error dynamics is input-to-state stable. Lookup tables, which are widely used to represent complex nonlinear characteristics of engine systems, appear in their original form in the designed reduced-order observer. The designed pressure observer is tested on an AMESim powertrain simulation model. Comparing with the sliding mode method, the designed pressure observer has the better performance.

A study of two-degree-of-freedom control of rotating speed in an automatic transmission, considering modeling errors of a hydraulic system

Abstract A proportional reducing valve is applied here to an automotive automatic transmission system to control shift operation. Its control system must be designed as a robust control system that considers modeling errors caused by changes in the characteristics of the valve. In this study, a braking mechanism of an automotive automatic transmission system is considered. Two-degree-of-freedom control of the rotating speed is studied, in which modeling errors due to changes in the characteristics of a proportional reducing valve are taken into account. A feedback controller is designed, based on μ synthesis, in which both changes in the characteristics of the valve and variations of a frictional coefficient are considered as uncertainties of a nominal model. Introducing a feedforward controller, a two-degree-of-freedom control system is constructed. The control system is examined through experiments using a commercial proportional reducing valve. The shift operation is precisely controlled by the control system under these fluctuating factors.

Observer-based clutch disengagement control during gear shift process of automated manual transmission

A clutch disengagement strategy is proposed for the shift control of automated manual transmissions. The control strategy is based on a drive shaft torque observer. With the estimated drive shaft torque, the clutch can be disengaged as fast as possible without large driveline oscillations, which contributes to the reduction of total shift time and shift shock. The proposed control strategy is tested on a complete powertrain simulation model. It is verified that the system is robust to the variations of driving conditions, such as vehicle mass and road grade. It is also demonstrated that the revised system with switched gain can provide satisfactory performance even under large estimation error of the engine torque.

Nonlinear feedforward–feedback control of clutch-to-clutch shift technique

To improve the shift quality of the vehicle with clutch-to-clutch gear shifts, a nonlinear feedforward–feedback control scheme is proposed for clutch slip control during the shift inertia phase. The feedforward control is designed based on flatness in consideration of the system nonlinearities, and the linear feedback control is given to accommodate the model errors and the disturbances. Lookup tables, which are widely used to represent complex nonlinear characteristics of powertrain systems, appear in their original form in the designed feedforward controller, while the linear feedback controller is calculated through linear matrix inequalities such that the control system is robust against the parameter uncertainties. Finally, the designed controller is tested on an AMESim powertrain simulation model, which contains a time-variant model of clutch actuators.

A finite Element Model of Hydraulic Pipelines Using an Optimized Interlacing Grid System

Simulation of flow and pressure variations in fluid pipelines using finite difference and finite element models can give unrealistic results, corresponding to errors in natural frequencies. A novel finite element model of hydraulic pipelines has been developed, using an interlacing grid system. The grid spacing is non-uniform and is optimized, using a genetic algorithm, to make some or all of the undamped natural frequencies of the model as close as possible to exact theoretical ones for a uniform pipe with the extreme boundary conditions of either constant pressure or no flow. Inaccuracies in the highest natural frequencies may be acceptable because of the effect of frequency-dependent friction and limited system frequency response. The optimized model gives accurate results in time domain simulation, and it allows variable properties and a variable integration step to be readily accommodated.

A method of designing a robust force controller of a water-hydraulic servo system

Abstract Robust force control of a water-hydraulic servo system is discussed. The system treated in this paper is a model of a moulding press used for a fabrication process of large-scale integration packages. The whole surface of a wafer is covered with a thin plastic layer by the press. The performance of force control is important to obtain sufficient quality. The press is driven by a ram cylinder and a water-hydraulic servo valve. Considering the uncertainty caused by the flow characteristics of the valve in the overlap region and the mechanical stiffness of the press, a method of designing a robust force controller is proposed by applying H∞ control theory. Qualitative evaluation of modelling error is the key to the design of the robust controller. The performance of the robust controller is examined using an experimental water-hydraulic servo system set-up. It is illustrated how the system responses are influenced by the weighting function parameters of H∞ control theory.

Observer-based feedback control during torque phase of clutch-to-clutch shift process

In order to improve the shift quality of Automatic Transmissions (ATs) adopting clutch-to-clutch shift technology, a feedback control strategy is proposed for the torque phase of shift process. With the estimated clutch torque, the off-going clutch is disengaged at the moment when transmitted torque is approaching zero, which contributes to the reduction of shift shock and prevention of clutch tie-up. The proposed control strategy is tested on a complete powertrain simulation model. It is verified that the system is robust to the variations of driving conditions, such as vehicle mass and road grade, etc.

A Study on Control of a Power-assisted Chair Based on Motion-sensing Concept

Generally, a power-assisting device should provide appropriate support for various physical conditions of persons who need supports. Therefore motion-sensing concept is introduced into the control system for the power-assisted chair, which is driven by a pneumatic cylinder. The concept is based on real-time modification of a desired path. The path is transformed with respect to time axis according to difference between a standard force pattern and an actual force pattern acting on a floor. This method is expected to realize more adaptive assisting. The control system was implemented to the power-assisted chair. The effect was investigated by experiment on the system

A reduced-order nonlinear clutch pressure observer for automatic transmission using ISS

For a new kind of automatic transmissions using proportional pressure valves to control the clutches directly, a clutch pressure observer design method is suggested in the concept of input-to-state stability (ISS). Model uncertainties including steady state errors and unmodelled dynamics are considered as additive disturbance inputs and the observer is designed such that the error dynamics is input-to-state stable. Lookup tables, which are widely used to represent complex nonlinear characteristics of engine systems, appear in their original form in the designed reduced-order observer. Finally, the designed pressure observer is tested on an AMESim powertrain simulation model.