Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Mitsubishi Denki K.k.

Shigeki Ohtagaki

Shunichi Wada

Shozo Takizawa

Kazunori Miura

Takayuki Kifuku

Tadao Tanaka

Yuji Takatsuka

Minoru Tatemoto

Mitsuhiko Harara

Yasutaka Taniguchi

Hiroshi Nishimura

Katsuhiko Ohmae

Susumu Zeniya

Norihiro Yamaguchi

Kazushi Kimura

Mitsunori Maruyama

Hirosi Watanabe

Tetsuya Terada

Kouji Mitsuhata

Hideyuki Tanaka

Masahiko Kurishige

Noriyuki Inoue

Kazumichi Tsutsumi

Takahiro Okanoue

Masanori Takagi

Yasuaki Hata

Kenji Hayase

Yoshihiro Tsuda

Kazuo Kikuta

Mitsuhiko Hara

Conventionally, there was a problem that in cases when it is difficult to place a temperature sensor in the vicinity of a heat-generating portion, overheating could not be prevented. Disclosed is an electric power steering control system including a torque sensor for detecting steering force of a steering system; a motor current determination unit for determining the motor current based on the steering force detected by the torque sensor; a temperature sensor for detecting an ambient temperature; a coefficient setting unit for setting a coefficient in accordance with the detected temperature obtained by means of the temperature sensor; a motor current detection unit for detecting a motor current being passed to a motor; a maximum current limit value calculation unit for calculating a maximum current limit value based on the detected current and the coefficient; a current limiting unit for selecting the smaller value between the motor current determined by the motor current determination unit and the maximum current limit value calculated and outputting this as a target current; and a motor current control section for passing the target current to the motor in such a way that the motor current is equal to the detected current, whereby a motor current limit being set according to temperature is applied.

Electric power steering control system

A road surface reaction torque detector has a low-pass filter element whose time constant is determined in accordance with a vehicle speed that is detected by a vehicle steed detector and a motor rotation speed that is detected by a motor rotation speed detector. A road surface reaction torque estimation value is obtained in such a manner that the road surface reaction torque detector performs low-pass filter processing on steering shaft reaction torque signal that is outputted by a steering shaft reaction torque signal outputting means. As a result, an accuracy of estimation of road surface reaction torque is improved.

Electric power steering control apparatus

A control apparatus for a motor-driven power steering system of a motor vehicle includes a steering angular information detecting means ( ) for detecting steering angular information of a steering mechanism ( ), a controller ( ) for controlling a motor current on the basis of the steering angular information and magnitude and direction of a steering torque, an electric motor ( ) operatively coupled to the steering mechanism ( ) for generating a steering assist torque (Ta) corresponding to the motor current, the assist torque being applied to a steering wheel, a motor-rotational information detecting means ( ) for detecting rotational information of the electric motor ( ), and an abnormality decision means ( ) designed to make decision that the steering angular information detecting means ( ) is abnormal when a difference between the steering angular information and the motor rotational information is not smaller than a reference value preset for comparison of both the information.

Control apparatus for motor-driven power-steering system of motor vehicle

Disclosed is a power steering system which involves no dedicated equipment, no increase in cost, and no such hardware operation for correction as the mounting of an adjusting resistor. The power steering system includes an external device which outputs an arbitrary torque signal in an error measurement mode, and an electric power steering control device which detects the torque signal, computes the differential between the detected torque value and a reference torque value, stores the differential as a torque correction value, and, in the actual control mode, uses the detected torque value after correcting it by the torque correction value, whereby it is possible to perform reading error correction on a software basis and to expedite and automate the correction.

Power steering system

In conventional electric power steering apparatus, a problem exists in that whether or not there is any failure in drive inhibiting means may be erroneously judged, and that it is impossible to judge whether or not a drive inhibition signal is normal. A steering torque detected by a torque sensor and a motor current outputted by motor drive means using a motor drive signal formed by CPU based on the steering torque are inputted to drive inhibiting means . The drive inhibiting means outputs a drive inhibition signal and a drive inhibition switch signal based on the relation between the inputted two signals. CPU detects that there is a failure in the drive inhibiting means based on the outputted signals. Upon detecting a failure, a control is conducted so that the motor current is set to 0.

Electric power steering apparatus

Electric power steering system

A method of detecting the angle of rotation of a DC motor includes the steps of: driving the DC motor with a predetermined torque for a predetermined period of time which is selected so that the angular acceleration of the DC motor is substantially constant during the above period of time; and calculating the angle of rotation of the DC motor from the driving time period and the voltage generated by the DC motor after the driving of the DC motor is stopped. This method makes it possible to accurately detect the angle of rotation and the load torque using an apparatus having a simple structure.

Method of detecting the angle of rotation and load torque of a DC motor,

A control apparatus for a motor-driven power steering system of a motor vehicle controls the steering system such that a steering torque required to be applied by a driver is prevented from increasing abruptly or steeply even when generation of an assist torque applied to the steering system for assisting the driver in steering operation is to be stopped. The control apparatus includes an operation stop decision mechanism (111, 112, OR) for deciding whether or not an operation stop command is to be issued for stopping control operation for the motor-driven power steering system, a torque detecting mechanism (16, 113) for detecting a steering torque transmitted from an input shaft (21a) to an output shaft (21c) of a steering column (21) of the motor-driven power steering system, and an assist torque control mechanism (114, 116, 117, 118, 13) for updating an assist torque applied by an electric motor (20) to the output shaft (21c) with an assist torque control quantity determined on the basis of a detected torque value outputted from the torque detection mechanism (16, 113), wherein upon issuance of the operation stop command by the operation stop decision mechanism (111, 112, OR), the assist torque control mechanism stops application of the assist torque, provided that the detected torque value is lower than a predetermined value inclusive thereof.

Control apparatus for motor-driven power steering system of motor vehicle

A motor driving apparatus which makes it possible to continue a suppressed power supply to an electric motor even when a detected value (Id) of a current flowing to an H-bridge circuit indicates abnormality, to thereby prevent occurrence of shock in a system in which the motor is employed as a drive source. The apparatus includes a current detecting device (12) for detecting an electric current (I) flowing to an H-bridge circuit (1), and a control device (20) which includes an abnormality decision device (24) for determining abnormality of the detected current value (Id) outputted from the current detecting device (12). When the detected current value (Id) indicates abnormality, both of the ones (Q1; Q4) of the transistors (Q1; Q2 and Q3; Q4) inserted at the side of the power supply source (3) and the ground (GND), respectively, are driven under the PWM control.

Motor driving apparatus

A suspension control system includes: a vehicle speed sensor for providing a signal representing a vehicle speed, a vehicle body behavior variation detecting device for detecting variations in behavior of a vehicle body, and a vehicle speed deciding device for calculating a vehicle speed from the signal provided by the vehicle speed sensor to compare the vehicle speed with a predetermined vehicle speed. The control system further includes a vehicle body behavior variation counter for counting vehicle body behavior variations for a predetermined period of time according to an output of the vehicle body behavior variation detecting device, a damping force changing device for changing a vehicle body suspension damping force at least in three steps and a damping force determining device for determining a damping force according to the vehicle speed decided by the vehicle speed deciding device and the number of vehicle body behavior variations counted by the vehicle body behavior variation counter, to apply an instruction signal to the damping force changing device, so that, when the vehicle speed decided by the vehicle speed deciding device is equal to or higher than a first predetermined vehicle speed, and when the number of vehicle body behavior variations counted by the vehicle body behavior variation counter is equal to or higher than a first predetermined value, the damping force changing device operates to increase the damping force to an increased value and to maintain the damping force at the increased value.

Suspension control system

A suspension control system having a suspension unit between a wheel and a body of a vehicle, a fluid supply device for supplying a fluid to the suspension unit, a fluid discharge device for discharging the fluid from the suspension unit, an amplitude measurement device for measuring the amplitude of vertical vibrations of the vehicle body, a threshold value setting device for setting a threshold value of the amplitude of vertical vibrations, a controller for cancelling expansion and contraction of the suspension unit by controlling the fluid supply and the fluid devices when the amplitude of vertical vibrations is equal to or larger than the threshold value, a counter for counting the number of times the fluid supply and fluid discharge devices are controlled by the controller in a predetermined time period, and a threshold value changing device for setting, when the number of times counted by the counter is equal to or larger than a reference number, the threshold value in the threshold value setting device to a value equal to or smaller than an upper limit but larger than a value to which the threshold value was set at a preceding time, and for setting the threshold value to a value equal to or larger than a lower limit but smaller than the value at the preceding time, when the counted number of times is smaller than the reference number.

Suspension control system using a variable threshold value to limit the

In a suspension control device, vertical acceleration detecting means detects an acceleration of a vehicle body in a vertical direction. A spring constant and damping force changing means for the suspensions of the vehicle body is provided. A vertical acceleration differential value measuring means measures the differential value of an output signal of the vertical acceleration detecting means which is larger than a predetermined level. A vertical acceleration period measuring means measures the magnitude and period of vibration of the output signal of the vertical acceleration detecting means. A first damping force and spring constant holding and setting means estimates a frequency of vibration of the vehicle body from the output signal of the vertical acceleration differential value measuring means, operating on the frequency thus estimated. A second damping force and spring constant holding and setting means operates on the frequency of vibration of the vehicle body which is obtained from the output signal of the vertical acceleration period measuring means. A spring constant and damping force changing control unit which, in accordance with the outputs of the first and second damping force and spring constant holding and setting means, changes the outputs of the spring constant and damping force changing means to desired levels simultaneously for the front and rear wheels, and maintains the outputs thus changed for a predetermined period of time.

Suspension control device

A suspension control system for a motor vehicle, includes a vertical accelerating detector for detecting a vertical acceleration of a vehicle body; a damping force changing device for switching suspension damping forces for the front and rear wheels of the vehicle body at least in three steps; a vertical acceleration differential value measuring device for measuring a differential value of an output signal of the vertical acceleration detector; and a damping force hold determining device for setting, according to an output of the vertical acceleration differential value measuring device, damping forces for the front and rear wheels to soft level simultaneously or setting damping forces for the rear wheels only to soft level and maintaining the damping forces.

Damping force control system for vehicle suspension

A rear differential gear allows to be locked by a differential gear lock switch at speeds less than a first set vehicle speed, prohibited from being locked at speeds greater than or equal to the first set vehicle speed, and automatically unlocked if the locked state elapses a predetermined period of time at speeds greater than or equal to a second set vehicle speed that is greater than the first set vehicle speed. Therefore, it can prevent reduction in driving stability due to the under-steering in a turning, even if a driver has forgotten unlocking the locked rear differential gear by operating the differential gear lock switch in a rear differential lock controller.

Growing community of inventors

Tokyo, Japan

Shigeki Ohtagaki