An electric power steering apparatus has a steering mechanism SM having universal joints 4, 6 in a torque transmitting system, a steering toque detecting unit 14, a steering angle detecting, unit 18, a torque fluctuation detecting unit 43 for detecting a torque fluctuation due to the crossing angle α in the universal joints 4, 6 on the basis of the steering angle θ detected by the steering angle detecting unit 18 and any one of the steering torque T detected by the steering torque detecting unit, a current command value It and self-aligning torque SAT; and a current command value correcting unit 44 for correcting the current command value on the basis of the torque fluctuation detected by the torque fluctuation detecting unit 43 and the steering angle θ detected by the steering angle detecting unit 18.

Electric Power Steering Apparatus

A motion control device for a vehicle includes a braking means for applying a brake torque to each of a plurality of wheels of the vehicle, an avoidance control means for calculating a first target quantity, used for an avoidance control for applying the brake torque to each wheel via the braking means in order to avoid an emergency state of the vehicle, a stabilization control means for determining a target wheel, to which the brake torque is applied, out of the wheels and calculating a second target quantity used for a stabilization control for applying the brake torque to the target wheel in order to ensure a vehicle stability, and a brake control means for controlling the brake torque applied to a non-target wheel based on the first target quantity and controlling the brake torque applied to the target wheel based on the first and second target quantities.

Motion control device for vehicle

A review of the engineering theory and the sensing element applications of the magnetostrictive delay line (MDL) technique is presented. The state of the art of magnetic materials and effects used in sensor design is overviewed and the operation of MDLs and their basic engineering properties are discussed. The resulting position, stress and field sensors based on this technique as well as their most significant applications are demonstrated. Finally, the industrialization process and the integration of the sensors with electronic circuitry as well as their evaluation with respect to the state of the art are discussed.

http://iopscience.iop.org/article/10.1088/0957-0233/14/2/201/pdf

Magnetostrictive delay lines: engineering theory and sensing applications

The target of our project is to realise a novel traction control system for an electric vehicle with four independently controlled in-wheel-motors. In each in-wheel-motor, the optimal slip ratio control is implemented beforehand to prevent wheel slip for vehicle stability control. The optimal slip ratio control is achieved by maintaining the slip ratio to the value to give the maximum road friction. This means that the driving force of the vehicle is fixed at its maximum level. As the driving force is affected by highly nonlinear adhesion characteristics between tire and road surface, real-time generation of the optimal slip ratio is necessary while the vehicle is moving. To estimate the adhesion characteristics, only the estimation of the slope of road friction curve is enough. To this aim, in this paper, the driving-force observer is newly designed to detect the road friction coefficient and the fixed-trace algorithm is applied to the slope estimation. The effectiveness of the proposed method is confirmed by simulation and experimental data obtained by laboratory-made electric vehicle "UOT Electric March".

Road condition estimation for traction control in electric vehicle

A driving/braking force manipulation control input of a k-th wheel, which denotes one or more specific wheels among a plurality of wheels of a vehicle, is determined such that a required condition concerning a relationship among a road surface reaction force that may act from a road surface on the k-th wheel on the basis of the detected values or estimated values of a side slip angle and a friction characteristic of the k-th wheel, a feedback control input related to the driving/braking force of the k-th wheel for bringing a difference between a state amount of the vehicle and a reference state amount close to zero, a driving/braking force feedforward control input based on a drive manipulated variable supplied by a driver of the vehicle, and a k-th wheel driving/braking force manipulation control input is satisfied. This arrangement makes it possible to properly control a motion of an actual vehicle to a desired motion while properly considering the characteristics of a road surface reaction force acting from a road surface on a wheel.

Vehicle Control Device

A physical amount estimating apparatus including first outputting means for outputting a first physical amount that does not include a hysteresis characteristic, second outputting means for outputting a second physical amount that has a predetermined physical relationship to the first physical amount and includes a hysteresis characteristic, hysteresis removing means for calculating a corrected value with the hysteresis characteristic removed therefrom based on the second physical amount, and estimating means for estimating a third physical amount based on a physical relationship between the first physical amount and the corrected value.

Physical amount estimating apparatus, road surface friction condition estimating apparatus, steering angle neutral point estimating apparatus and air pressure reduction estimating apparatus

In this paper, we propose a new control strategy for an antilock braking system (ABS) to maintain the braking force at maximum. The popularization of the ABS that prevents the wheels from locking has resulted in an improvement of the vehicle stability and shortening of the braking distance. Further improvement is anticipated if the maximization of the braking force is realized. We found an interesting phenomenon in which the characteristics of the resonance system composed of the vehicle body and the wheel and road surface reflects the slip condition of the road surface. Using this phenomenon, we realized a control method for maintaining the maximum value of the braking force.

New Control Technique for Maximizing Braking Force on Antilock Braking System

A torque sensor which can detect instantaneous output torque of the engine is disposed on the output shaft of the engine, and the output signal thereof is frequency-analyzed to extract a half synchronous frequency component having a frequency equals to a half of the number of the revolutions of the engine per second and a synchronous frequency component having a frequency equals to the number of the revolutions of the engine per second, the electronic control unit (ECU) of the engine determines the misfiring mode of the engine including the number of the misfiring cylinders and the interval thereof in the firing order of the engine based on the amplitude of the frequency components and the waveform thereof, then the ECU determines the misfiring cylinders based on the determined misfiring mode and the phase angle of the frequency components of the torque sensor relative to a reference crank angle signal.

Device for determining misfiring of cylinders in multi-cylinder engines

A tire parameter estimation device that is economical and can accurately estimate tire parameters while taking into consideration both states of a vehicle and states of a road environment. A μ gradient detecting circuit detects a μ gradient on the basis of a wheel speed detected by a wheel speed detecting circuit. A gradient value comparing circuit determines a μ gradient section value μr, which is a mean value of the μ gradients from the μ gradient detecting circuit, and calculates a rate (=μr/μI) of the μ gradient mean value μr with respect to a μ gradient initial value μ. A tire temperature estimating circuit stores a table representing the relation between the rate and a tire temperature, and estimates a tire temperature corresponding to the rate calculated by the gradient value comparing circuit as the present tire temperature.

Tire parameter estimation device and road surface judgment device

PROBLEM TO BE SOLVED: To accurately estimate the friction condition of a road surface without the need for additional steering angles. SOLUTION: A slipping angle estimating means 34 estimates the slipping angle of a front wheel in accordance with a steering angle and a vehicle speed, an SAT estimating means 36 estimates SAT in accordance with steering torque and assisting torque, and a slipping angle reference value computing means 38 computes a slipping angle reference value for an estimated value for the SAT. An friction condition estimating means 40 estimates a gripping condition by utilizing the fact that the degraded gripping condition causes the slipping angle to be larger as compared with the slipping angle reference value. A steering angle neutral point and the pneumatic pressure drop of a tire are also estimated. COPYRIGHT: (C)2003,JPO

Physical quantity estimating device, road surface friction condition estimating device, steering angle neutral point estimating device and pneumatic pressure drop estimating device

Masanori Miyashita

Papers

Physical amount estimating apparatus, road surface friction condition estimating apparatus, steering angle neutral point estimating apparatus and air pressure reduction estimating apparatus

New Control Technique for Maximizing Braking Force on Antilock Braking System

Device for determining misfiring of cylinders in multi-cylinder engines

Tire parameter estimation device and road surface judgment device

Physical quantity estimating device, road surface friction condition estimating device, steering angle neutral point estimating device and pneumatic pressure drop estimating device